As filed with the Securities and Exchange Commission on August 10, 2001
                                                      Registration No. 333-50906

- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                ---------------
                         POST-EFFECTIVE AMENDMENT NO. 1
                                       TO
                                    FORM S-1
                                       ON
                                    FORM S-3
                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933

                                ---------------
                                  Curis, Inc.
             (Exact name of Registrant as specified in its charter)
                                ---------------

                                                  
          Delaware                   2836                     04-3505116
      (State or other
      jurisdiction of
      incorporation or   (Primary Standard Industrial      (I.R.S. Employer
       organization)     Classification Code Number)    Identification Number)


                               61 Moulton Street
                         Cambridge, Massachusetts 02138
                                 (617) 503-6500
         (Address, including zip code, and telephone number, including
            area code, of registrant's principal executive offices)
                                ---------------
                              Doros Platika, M.D.
                            Chief Executive Officer
                               61 Moulton Street
                         Cambridge, Massachusetts 02138
                                 (617) 503-6500
 (Name, address, including zip code, and telephone number, including area code,
                             of agent for service)

                                With copies to:

    Steven D. Singer, Esq.                      James R. Tanenbaum, Esq.
      Hale and Dorr LLP                           Anna T. Pinedo, Esq.
       60 State Street                       Stroock & Stroock & Lavan LLP
 Boston, Massachusetts 02109                        180 Malden Lane
        (617) 526-6000                          New York, New York 10038
                                                     (212) 806-5400
                                ---------------
   Approximate date of commencement of proposed sale to the public: As soon as
practicable after this Registration Statement becomes effective.

   If any of the securities being registered on this form are to be offered on
a delayed or continuous basis pursuant to Rule 415 under the Securities Act of
1933, check the following box. [X]

   If this form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, check the following box and
list the Securities Act registration statement number of the earlier effective
registration statement for the same offering. [_]

   If this form is a post-effective amendment filed pursuant to Rule 462(c)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering. [_]

   If this form is a post-effective amendment filed pursuant to Rule 462(d)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering. [_]

   If delivery of the prospectus is expected to be made pursuant to Rule 434,
check the following box. [_]
                                ---------------
   THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE OR
DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT
SHALL FILE A FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS REGISTRATION
STATEMENT SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(A) OF
THE SECURITIES ACT OF 1933, AS AMENDED, OR UNTIL THE REGISTRATION STATEMENT
SHALL BECOME EFFECTIVE ON SUCH DATE AS THE SECURITIES AND EXCHANGE COMMISSION,
ACTING PURSUANT TO SAID SECTION 8(A), MAY DETERMINE.
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------


                              [LOGO APPEARS HERE]

                                5,200,000 Shares

                                  Common Stock

   The selling stockholders intend to sell 5,200,000 shares of our common
stock. We will not receive any of the proceeds from the sale of shares by the
selling stockholders. The common stock is traded on the Nasdaq National Market
under the symbol "CRIS." The last reported sale price of the common stock on
the Nasdaq National Market on July 31, 2001 was $6.20 per share.

   The selling stockholders have acquired the offered shares directly from us
in a private placement. The selling stockholders may sell the shares at prices
determined by the prevailing market price for the shares or in negotiated
transactions. The selling stockholders may also sell the shares to or with the
assistance of broker-dealers, who may receive compensation in excess of their
customary commissions.

           Investing in our common stock involves significant risks.
                    See "Risk Factors" beginning on page 3.

                               ----------------

   Neither the Securities and Exchange Commission nor any state securities
commission has approved or disapproved of these securities or passed upon the
accuracy or adequacy of this prospectus. Any representation to the contrary is
a criminal offense.

                               ----------------

                 The date of this Prospectus is August  , 2001.


                               TABLE OF CONTENTS


                                                                          
   PROSPECTUS SUMMARY.......................................................   1
   RISK FACTORS.............................................................   3
   SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS........................  14
   USE OF PROCEEDS..........................................................  14
   SELLING STOCKHOLDERS.....................................................  15
   PLAN OF DISTRIBUTION.....................................................  16
   LEGAL MATTERS............................................................  18
   EXPERTS..................................................................  18
   ADDITIONAL INFORMATION...................................................  18
   WHERE YOU CAN FIND MORE INFORMATION......................................  18
   INCORPORATION BY REFERENCE...............................................  19


                               ----------------

   We have not authorized anyone to provide you with information different from
that contained or incorporated by reference in this prospectus. The selling
stockholders are offering to sell, and seeking offers to buy, shares of our
common stock only in jurisdictions where offers and sales are permitted. The
information contained in this prospectus is accurate only as of the date of
this prospectus, regardless of the time of delivery of this prospectus or of
any sale of our common stock. Unless the context otherwise requires, references
in this prospectus to "Curis," "we," "us," and "our" refer to Curis, Inc. and
its subsidiaries.


                               PROSPECTUS SUMMARY

   This summary highlights important features of this offering and the
information included or incorporated by reference in this prospectus. This
summary does not contain all of the information that you should consider before
investing in our common stock. You should read the entire prospectus carefully,
especially the risks of investing in our common stock discussed under "Risk
Factors."

                                     Curis


            
 Our Business: We intend to be a leader in the emerging field of regenerative
               medicine, which seeks to improve, restore or preserve the normal
               function of tissues and organs by harnessing the body's inherent
               ability to repair damage caused by disease, trauma or age. By
               applying our knowledge of how genes function (functional
               genomics) and our knowledge of how cells develop into
               specialized adult tissues (developmental biology), we believe we
               will be able to activate cellular development pathways to
               promote repair and promote normal tissue and organ function, and
               inhibit abnormal growth pathways to treat certain types of
               cancer.


           We began operations on July 31, 2000 upon the completion of the
           merger of Creative BioMolecules, Inc., Ontogeny, Inc. and
           Reprogenesis, Inc. Each of these three companies made important
           contributions to the combined strength of our business. At the time
           of the merger, those contributions included the following:


                              
          Ontogeny:              Validated developmental biology and functional
                                 genomic discovery engine

          Reprogenesis:          Clinical development, regulatory affairs, quality
                                 assurance, manufacturing, biomaterials and tissue
                                 engineering
                                 expertise

          Creative BioMolecules: Lead product awaiting regulatory review and
                                 significant antibody and developmental biology
                                 intellectual property


           Our product development pipeline includes a product which has been
           approved in Europe and Australia and is under regulatory review in
           the United States; a product in late-stage clinical development;
           multiple early clinical and advanced preclinical products; and a
           discovery engine that combines functional genomics, use of adult
           stem cells, and developmental biology across multiple therapeutic
           areas. By harnessing the body's inherent ability to repair damage
           caused by disease, trauma or age, we believe the products in our
           development pipeline have the potential to change the way
           degenerative disease, cancer and other disorders associated with
           loss of normal function are treated.


           
 Our Address: Our principal executive offices are located at 61 Moulton Street,
              Cambridge, Massachusetts 02138. Our telephone number is (617)
              503-6500. Our website is located at www.curis.com. Information
              contained in our website is not a part of this prospectus.


                                       1



                                  The Offering


                    
 Selling Stockholders: The selling stockholders are accredited investors that
                       have acquired the shares of our common stock being
                       offered by this prospectus on December 20, 2000 in a
                       private placement.

 Common Stock Offered: All of the 5.2 million shares being offered by this
                       prospectus are being sold by the selling stockholders.
                       We do not know when or in what amounts the selling
                       stockholders may offer their shares for resale.

                       We will not receive any proceeds from the sale of shares
 Use Of Proceeds:      in this offering.


                                       2


                                  RISK FACTORS

   An investment in our common stock involves a high degree of risk. You should
carefully consider the following information about these risks, together with
the other information contained in this prospectus, before you decide to
purchase our common stock. If any of the following risks actually occur, our
business, results of operations and financial condition would likely suffer. In
these circumstances, the market price of our common stock could decline, and
you may lose all or part of your investment. Please read "Special Note
Regarding Forward-Looking Statements."

Risks Related to Our Business, Industry, Strategy and Operations

   We are dependent on collaborative partners for the development and
commercialization of many of our products. Any failure or delay by these
partners in developing or commercializing our products could eliminate
significant portions of our anticipated product pipeline.

   Our strategy for development and commercialization of many of our products
depends upon the formation of collaborations and strategic alliances. We have
entered into strategic alliances with Stryker Corporation, Micromet AG, Elan
Corporation, plc, Aegera Therapeutics Inc. and other companies, and plan to
enter into additional alliances. If the products developed as a result of these
alliances are not approved for commercial sale in the United States and/or
throughout the rest of the world, our royalty revenues will be diminished and
our business will be materially and adversely affected. In addition, we may not
be able to establish new collaborations and strategic alliances necessary to
develop and commercialize products based upon our research efforts, or to
establish such arrangements on terms favorable to us. We have limited control
over the amount of resources and the schedule of product development in our
collaborations with strategic partners and may not be able to control the
efforts that any future strategic partners may devote to their respective
programs with us. The timing and amount of any future royalties and
manufacturing revenues with respect to product sales and product development
under such collaborative arrangements will therefore depend on the level of
commitment, timing and success of such collaborative partners' efforts.
Accordingly, we cannot predict the success of current or future strategic
alliances.

   As we proceed with our research and development efforts, we regularly review
opportunities to establish new collaborations, joint ventures and strategic
alliances to develop, commercialize, manufacture and market products in our
development pipeline. If we determine it is necessary to establish certain new
collaborations, joint ventures, or strategic alliances and we are unable to
establish favorable arrangements to commercialize our products, we may elect to
limit funding for some products in our development pipeline.

   We have not commercialized any products to date, and if we do not
commercialize any products we will not be profitable.

   Even though Stryker has recently received approval to market OP-1 in Europe
and Australia, to date, we have not commercialized the types of products that
we or our collaborative partners are and will be developing. Many of these
types of products may require additional research and development, clinical
trials and/or regulatory resources and/or expertise prior to any commercial
sale.

   We currently have no products for sale by us or our collaborative partners.
Stryker has indicated that it may begin to sell OP-1 in Europe and Australia by
the end of 2001. If, however, we or our collaborative partners are not
successful in developing and commercializing additional products in the United
States and globally, we will not become profitable.


   We face substantial competition, which may result in others discovering,
developing or commercializing products before or more successfully than we do.

   The products that we will be developing compete with existing and new
products being created by pharmaceutical, biopharmaceutical, biotechnology and
medical device companies, as well as universities and other research
institutions. Many of our competitors are substantially larger than we are and
have substantially

                                       3


greater capital resources, research and development staffs and facilities than
we have. Efforts by other biotechnology or pharmaceutical companies could
render our programs or products uneconomical or result in therapies superior to
those that we develop. Furthermore, many of our competitors are more
experienced in product development and commercialization, obtaining regulatory
approvals and product manufacturing. As a result, they may develop competing
products more rapidly and at a lower cost. These competitors may discover,
develop and commercialize products which render non-competitive or obsolete the
products that we or our collaborative partners are seeking to develop and
commercialize.

   Other companies are engaged in the research and development of proteins for
various applications. We believe that other biopharmaceutical companies also
are developing proteins, primarily growth factors, for use in the local repair
of orthopaedic and skeletal defects and in other indications. In addition, a
number of other companies are pursuing traditional therapies that may compete
with our products, including bone grafts and electrical stimulation devices for
the repair of orthopaedic and other skeletal defects.

   In the field of tissue engineering and the treatment of damaged or diseased
tissue, we compete with several companies that are developing various tissue
replacement products. In addition, a number of biotechnology, pharmaceutical
and medical device companies are developing other types of products as
alternatives to tissue replacement/augmentation for a variety of indications.

   For example, vesicoureteral reflux is a pediatric disorder of the urinary
tract involving the backflow of urine from the bladder to the kidneys.
Vesicoureteral reflux is currently treated in the United States either by
surgery or with antibiotics; however, a number of other bulking agents, such as
bovine dermal collagen, a substance derived from the skin of cows, synthetic
materials and other biomaterials (such as dextranomer beads in a hydrogel), are
being evaluated for use in its treatment. Deflux, which in 2000 was recommended
for approval by an advisory panel for FDA for use in the United States and is
already approved for use outside of the United States, is an example of a
competing bulking agent. If Deflux were to be approved by the FDA, our
Chondrogel product may be materially adversely impacted.

   In the area of cardiovascular medicine, several approaches are currently
being developed by major medical device, pharmaceutical and biotechnology
companies to reduce restenosis or the re-narrowing of treated blood vessels,
associated with current cardiovascular therapies. These approaches include,
among others, local and systemic drug therapy, locally delivered radiation,
gene therapy, and improved stents and stenting techniques.

   In addition, research in the fields of stem cells, developmental biology and
functional genomics is highly competitive. Our competitors in the field of stem
cells include, among others, Advance Tissue Sciences, Inc., Bresagen, Ltd.,
Geron Corporation, Incara Pharmaceuticals Corporation, StemCells, Inc. and
Titan Pharmaceuticals, Inc., as well as other private companies and major
pharmaceutical companies. Our competitors in the field of developmental biology
include, among others, Amgen, Inc., Chiron Corporation, Exelixis, Inc.,
Genentech, Inc. and Geron Corporation, as well as other private companies and
major pharmaceutical companies. Competitors in the genomics area include, among
others, public companies such as Axys Pharmaceuticals, Inc., Genome
Therapeutics Corporation, Human Genome Sciences, Inc., Incyte Pharmaceuticals,
Inc., Millennium Pharmaceuticals, Inc. and Myriad Genetics, Inc., as well as
private companies and major pharmaceutical companies. We also compete with
universities and other research institutions, including those receiving funding
from the federally funded Human Genome Project. A number of entities are
attempting to identify and patent rapidly randomly sequenced genes and gene
fragments, typically without specific knowledge of the function of such genes
or gene fragments. In addition, we believe that certain entities are pursuing a
gene identification and characterization and product development strategy based
on positional cloning. Our competitors may discover, characterize and develop
important inducing molecules or genes in advance of us. We also face
competition from these and other entities in gaining access to DNA samples used
in our research and development projects. We expect competition to intensify in
genomics research and developmental biology as technical advances in the field
are made and become more widely known.

   We rely on our strategic partners for support in our disease research
programs and intend to rely on our strategic partners for preclinical
evaluation and clinical development of our potential products and manufacturing
and marketing of any products. Some of our strategic partners are conducting
multiple product

                                       4


development efforts within each disease area that is the subject of our
strategic alliance with them. Our strategic alliance agreements may not
restrict a strategic partner from pursuing competing internal development
efforts. Any of our product candidates, therefore, may be subject to
competition with a potential product under development by a strategic partner.

   Public attitudes towards stem cell research may negatively affect regulatory
approval or public perception of our products.

   Our strategy for the development and commercialization of several of our
product candidates will depend in part on our collaboration with Aegera
Therapeutics, which involves stem cell research. Public acceptance of the use
of stem cell research in the development of new cell-based therapies for the
prevention or treatment of human diseases may negatively affect our ability to
execute on this part of our strategy. Public attitudes towards our business may
be influenced by claims that stem cell research is unsafe or unethical, and
cell therapy may not gain the acceptance of the public or the medical
community. Adverse effects in the field of cell therapy that have occurred or
may occur in the future also may result in greater governmental regulation of
our product candidates and potential regulatory delays relating to the testing
or approval of our product candidates.

   The use of certain human stem cells gives rise to ethical, legal and social
issues regarding the appropriate use of these cells. In the event that our
research related to human stem cells becomes the subject of adverse commentary
or publicity, the market price for our common stock could be significantly
harmed.

   The market may not be receptive to our products due to their use of new
technologies or cost. Such a lack of reception could limit our sales of these
and future products.

   The commercial success of our products that are approved for marketing will
depend upon their acceptance by patients, the medical community and third-party
payors. OP-1, a biological device being developed by our strategic partner
Stryker, is a new form of treatment for orthopaedic reconstruction, and will
require a change from the current standard of care. Chondrogel, currently being
developed for the vesicoureteral reflux indication, is based on the new
technology of tissue engineering. These products may never gain commercial
acceptance among physicians, patients and third-party payors, even if necessary
marketing approval is obtained. We believe that recommendations and
endorsements by physicians will be essential for market acceptance of our
products.

   In addition, Chondrogel is an autologous cell-based product, meaning that a
patient's own cells are used to treat a medical condition. Chondrogel may be
more costly than other competitive bulking products because each cell batch
must be handled individually. Therefore, traditional scale-up technologies are
not applicable in our manufacturing process. We may not be able to manufacture
products that will be cost effective or, if we can, our products may not
receive commercial and market acceptance.

   Our growth could be limited if we are unable to attract and retain key
personnel and consultants.

   Our success is substantially dependent on our ability to attract and retain
qualified scientific and technical personnel for the research and development
activities we conduct or sponsor. If we lose one or more of the members of our
senior management or other key employees or consultants, our business and
operating results could be seriously harmed. Only a limited number of the
members of our senior management or other key employees, including Doros
Platika, M.D., our President and Chief Executive Officer, Andrew Uprichard, our
Executive Vice President and Chief Operating Officer, and Danial Passeri, our
Senior Vice President, Corporate Development and Stratigic Planning have
entered into employment agreements that provide for severance payments if they
are terminated without cause.

   Our anticipated growth and expansion into areas and activities requiring
additional resources or expertise, such as regulatory affairs, compliance,
manufacturing and marketing, will require the addition of new key personnel.
The pool of personnel with the skills that we require is limited. Competition
to hire from this limited pool is intense, and we may not be able to hire,
train, retain or motivate such additional personnel.

                                       5


   If we fail to obtain an adequate level of reimbursement for our future
products or services by third-party payors, there may be no commercially viable
markets for our products.

   The availability of reimbursement by governmental and other third-party
payors affects the market for any pharmaceutical product. These third-party
payors continually attempt to contain or reduce the costs of healthcare by
challenging the prices charged for medical products. In some foreign countries,
particularly the countries of the European Union, the pricing of prescription
pharmaceuticals is subject to governmental control. We may not be able to sell
our products profitably if reimbursement is unavailable or limited in scope or
amount.

   In both the United States and some foreign jurisdictions, there have been a
number of legislative and regulatory proposals to change the healthcare system.
Further proposals are likely. The potential for adoption of some or all of
these proposals affects or will affect our ability to raise capital, obtain
additional collaborative partners and market our products.

   If we or our collaborative partners obtain marketing approval for our
products, we expect to experience pricing pressure due to the trend toward
managed health care, the increasing influence of health maintenance
organizations and additional legislative proposals.

   We could be exposed to significant risk from liability claims if we are
unable to obtain insurance at acceptable costs or otherwise protect ourselves
against potential product liability claims.

   We may be subjected to product liability claims that are inherent in the
testing, manufacturing, marketing and sale of human health care products. These
claims could expose us to significant liabilities that could prevent or
interfere with the development or commercialization of our products. Product
liability claims could require us to spend significant time and money in
litigation or to pay significant damages. Product liability insurance is
generally expensive for biopharmaceutical companies such as ours. Although we
maintain limited product liability insurance coverage for the clinical trials
of our products, it is possible that we will not be able to obtain further
product liability insurance on acceptable terms, if at all, and that our
present insurance levels and insurance subsequently obtained will not provide
adequate coverage against all potential claims.

Risks Relating to Financing

   We have incurred substantial losses, we expect to continue to incur losses
and we may never achieve profitability.

   We expect to incur substantial operating losses for the foreseeable future.
We currently have no material sources of revenue from product sales or license
fees. It is uncertain when, if ever, we will develop significant revenue
sources or become profitable, even if we are able to commercialize products. In
addition, because certain of our product candidates consist of living cells,
they may be more expensive to manufacture than conventional therapeutic
products.

   We expect to increase our spending significantly as we continue to expand
our research and development programs, expand our clinical trials, apply for
regulatory approvals and begin commercialization activities. As a result, we
will need to generate significant revenues in order to achieve profitability.
We cannot be certain whether or when this will occur because of the significant
uncertainties that affect our business.

   We may require additional financing, which may be difficult to obtain and
may dilute your ownership interest in us.

   We will require substantial funds to continue our research and development
programs, including clinical trials of our product candidates, and to
manufacture and market any products that are approved for commercial sale. Our
future capital requirements will depend on many factors, including the
following:

  . continued progress in our research and development programs, as well as
    the magnitude of these programs;

                                       6


  . the resources required to initiate and then successfully complete our
    clinical trials for Chondrogel, Vascugel, Cur-61414 and other product
    candidates;

  . the time and costs involved in obtaining regulatory approvals for
    Chondrogel, Vascugel, Cur-61414 and other product candidates;

  . the cost of manufacturing and commercialization activities;

  . the cost of any additional facilities requirements;

  . the timing, receipt and amount of milestone and other payments from
    collaborative partners such as Stryker;

  . the timing, payment and amount of milestone license, royalty payments,
    research funding and royalties due to licensors of patent rights and
    technology used to make, use and sell our product candidates;

  . the timing, receipt and amount of sales revenues and royalties from our
    potential products in the market; and

  . the costs involved in preparing, filing, prosecuting, maintaining and
    enforcing patent claims and other patent-related costs, including
    litigation costs and the costs of obtaining any required licenses to
    technologies.

   We estimate that it will cost at least $60 million to fund our operations
until the end of 2002. At June 30, 2001, we had cash, cash equivalents and
marketable securities of approximately $59 million, and with additional
revenues from corporate partnerships and other revenues, we believe we will
have sufficient capital resources to fund our operations into 2003. We may seek
additional funding through collaborative arrangements and public or private
financings. However, the biotechnology market is highly volatile and, depending
on market conditions and the state of our research, development and
commercialization programs, additional financing may not be available to us on
acceptable terms or at all. If we fail to obtain such additional financing, our
ability to continue all of our research, development, commercialization,
manufacturing and marketing activities may be significantly diminished.

   If we raise additional funds by issuing equity securities, further dilution
to our then existing stockholders will result. In addition, the terms of the
financing may adversely affect the holdings or the rights of our stockholders.
If we are unable to obtain funding on a timely basis, we may be required to
significantly curtail one or more of our research or development programs. We
also could be required to seek funds through arrangements with collaborative
partners or others that may require us to relinquish rights to certain of our
technologies, product candidates or products which we would otherwise pursue
independently.

Risks Relating to Clinical and Regulatory Matters

   If our clinical trials are not successful, we will not be able to complete
development and market or commercialize our products.

   In order to obtain regulatory approval for the commercial sale of our
product candidates, we will be required to complete extensive preclinical
studies as well as clinical trials in humans to demonstrate the safety and
efficacy of our products. We have limited experience in conducting clinical
trials and rely at times on contract research organizations and collaborative
partners for their performance and management.

   We cannot assure you that clinical trials of OP-1, Chondrogel, Vascugel or
other product candidates under development will be sufficient to obtain
regulatory approvals for the indications being studied. Furthermore, the timing
and completion of the current and planned clinical trials for Chondrogel and
Vascugel, Stryker's current and planned clinical trials of OP-1, as well as
clinical trials of other products, depend on, among other factors, the numbers
of patients required for approval and the rate at which those patients are
enrolled. In our clinical

                                       7


trials, more than the anticipated number of patients could be required and
enrollment may not proceed at the predicted rate. Any increase in the number of
patients or decrease in recruitment rates may result in increased costs,
program delays or both. Also, these products may not be effective in treating
any of our targeted disorders or may prove to have undesirable or unintended
side effects, toxicities or other characteristics that may prevent or limit
their commercial use.

   Progress in the area of orthopaedic reconstruction and dental applications
is within the exclusive control of Stryker. Even though Stryker has received
approval for the commercialization of OP-1 in Europe and Australia, our
business could be adversely affected if Stryker is unable to obtain FDA
approval for the commercialization of OP-1 in the United States. For example,
Stryker filed a Pre-Market Approval (PMA) application for OP-1, which was
accepted by the FDA in June 1999. On January 29, 2001, Stryker announced that
it had received a not-approvable letter from the FDA regarding its PMA for OP-
1. As reported by Stryker, the deficiencies cited in the letter relate
primarily to the lack of statistical equivalence as compared to the control
treatment of autograft in the clinical trial for tibial nonunions. The FDA has
recommended that Stryker conduct a new study. As shown by the Stryker example,
the timing of the regulatory process is unpredictable and it is uncertain
whether or when approvals will be obtained from the FDA or other regulatory
agencies for any use of OP-1.

   We could also experience delays in our preclinical trials of any of our
product candidates, unfavorable results in any development program, failure to
obtain regulatory approval for the commercialization of any of our products or
failure to achieve market acceptance of any approved products. Any of these
events would have a negative impact on our ability to market a product.

   The development process necessary to obtain regulatory approval is complex,
costly and lengthy and we may not obtain necessary regulatory approvals.

   We and our collaborative partners must obtain regulatory approval for
ongoing development activities and before marketing or selling any of our
products. We may not receive regulatory approvals to conduct clinical trials of
our products or to manufacture or market our products. In addition, regulatory
agencies may not grant approvals on a timely basis or may revoke or
significantly modify previously granted approvals. Any delay in obtaining, or
failure to obtain, approvals could adversely affect the marketing of our
products and our ability to generate product revenue.

   The process of obtaining FDA and other required regulatory approvals is
lengthy and expensive. The time required for FDA and other clearances or
approvals is uncertain and typically takes a number of years, depending on the
complexity and novelty of the product. The process of obtaining FDA and other
required regulatory approvals for many of our products is further complicated
because some of these products use non-traditional or novel materials in non-
traditional or novel ways, and the regulatory officials have little precedent
to follow. We have only limited experience in filing and prosecuting
applications for the conduct of clinical studies and for obtaining marketing
approval. Any delay in obtaining or failure to obtain required clearance or
approvals would reduce our ability to generate revenues from the affected
product. We also plan to rely significantly on contract research organizations
and collaborative partners as we build internal capabilities.

   Our analysis of data obtained from preclinical and clinical activities is
subject to confirmation and interpretation by regulatory authorities, which
could delay, limit or prevent regulatory approval. Any regulatory approval to
market a product may be subject to limitations on the indicated uses for which
we may market the product. These limitations may restrict the size of the
market for the product and affect reimbursement by third party payors.

   We also are subject to numerous foreign regulatory requirements governing
the design and conduct of the clinical trials and the manufacturing and
marketing of our future products outside of the United States. The approval
procedure varies among countries and the time required to obtain foreign
approvals often differs from that required to obtain FDA approvals. Moreover,
approval by the FDA does not ensure approval by regulatory authorities in other
countries, and vice versa.

   Our ability to conduct preclinical research is also subject to new and
evolving regulations governing the use of human and embryonic tissues for
isolating new growth factors and genes which may be useful in

                                       8


identifying and developing new therapeutic product candidates. Our ability to
conduct critical research on which our future development activities are based
could be restricted or delayed depending on the outcome of pending rulemaking
proceedings governing the use of these tissues and the collection of related
genetic information.

   Even if we obtain marketing approval, our products will be subject to
ongoing regulatory oversight which may affect our ability to successfully
commercialize any products we develop.

   Even if we receive regulatory approval of a product, the approval may be
subject to limitations on the indicated uses for which the product is marketed
or contain requirements for costly post-marketing follow-up studies. After we
obtain marketing approval for any product, the manufacturer and the
manufacturing facilities for that product will be subject to continual review
and periodic inspections by the FDA and other regulatory authorities. The
subsequent discovery of previously unknown problems with the product, or with
the manufacturer or facility, may result in restrictions on the product or
manufacturer, including withdrawal of the product from the market.

   If we fail to comply with applicable regulatory requirements, we may be
subject to fines, suspension or withdrawal of regulatory approvals, product
recalls, seizure of products, operating restrictions, and criminal prosecution.

   We may not be able to comply with other governmental regulations, which
could subject us to penalties and otherwise result in the limitation of our
operations.

   In addition to comprehensive regulation by the FDA, we are subject to
regulation under the Occupational Safety and Health Act, the Environmental
Protection Act, the Toxic Substances Control Act, the Research Conservation and
Recovery Act, regulations administered by the Nuclear Regulatory Commission,
national restrictions on technology transfer, import, export and customs
regulations and certain other local, state or federal regulation. From time to
time, other federal agencies and congressional committees have indicated an
interest in implementing further regulation of biotechnology applications. We
are not able to predict whether any such regulations will be adopted or
whether, if adopted, such regulations will apply to our business, or whether we
would be able to comply with any applicable regulations.

   Our research and development activities involve the controlled use of
hazardous materials and chemicals. Although we believe that our safety
procedures for handling and dispersing of such materials comply with all
applicable laws and regulations, we cannot completely eliminate the risk of
accidental contamination or injury from these materials.

Risks Relating to Product Manufacturing, Marketing and Sales

   We have limited manufacturing capabilities and may be unable to expand our
manufacturing capabilities as required to meet demand for our products.

   We have limited experience or capabilities in large-scale commercial
manufacturing of any of our product candidates. Our current facilities and
staff are inadequate for commercial production and distribution of products.
Our marketing plan for Chondrogel may involve in-house manufacturing of this
product. We may not be able to attract, train and retain the required personnel
or to expand our manufacturing capability to manufacture commercial quantities
of Chondrogel or any of our other products in a timely manner. Our
manufacturing scale-up efforts may not be successful, and we may not be able to
establish or maintain reliable, high-volume manufacturing capabilities at
commercially reasonable costs on a timely basis, or at all. In addition,
potential efforts to contract for manufacture of Chondrogel may not be
successful.

   Delays in obtaining regulatory approval of our manufacturing facility and
disruptions in our manufacturing process may delay or disrupt our
commercialization efforts.

                                       9


   Before we can begin commercially manufacturing our product candidates, we
must obtain regulatory approval for our manufacturing facility and process.
Manufacturing of our product candidates must comply with the regulations of the
FDA and with foreign regulatory authorities, including current good
manufacturing practices (cGMP). The cGMP regulations provide a framework that
describe the minimum practices, facilities and controls to be used for the
manufacture, processing, packing and holding of a medicinal product to assure
that the product meets the established requirements for safety and
effectiveness and govern manufacturing methods, quality control and
documentation policies and procedures. In complying with cGMP and foreign
regulatory requirements, we will be obligated to expend time, money and effort
in production, record keeping and quality control to assure that the product
meets applicable specifications and other requirements. If we fail to comply
with these requirements, we would be subject to possible regulatory action and
may be limited in the jurisdictions in which we are permitted to sell our
product candidates.

   We have no sales and marketing experience or infrastructure, which could
impair or delay our ability to commercialize our products.

   We have no sales, marketing and distribution experience or infrastructure.
We plan to develop small specialty sales, marketing and distribution
capabilities for the sale, marketing and distribution of Chondrogel and other
specialty products. However, we may not be able to successfully develop this
sales, marketing and distribution capability. With respect to all of our other
products which address larger markets, we plan to rely significantly on sales,
marketing and distribution arrangements with third parties for the products
that we are developing until we are able to develop more significant internal
sales, marketing and distribution capabilities. We may have limited or no
control over the sales, marketing and distribution activities of our present or
future collaborative partners. Our future revenues may be materially dependent
upon the success of the efforts of these third parties.

   In determining whether to perform sales, marketing and distribution
functions ourselves, we face a number of risks, including:

  . not being able to attract and build a significant marketing staff or
    sales force;

  . the cost of establishing a marketing staff or sales force may not be
    justifiable in light of any product revenues; and

  . the failure of our direct sales and marketing efforts to be successful.

Risks Relating to Intellectual Property

   We may not be able to obtain patent protection for our discoveries and we
may infringe patent rights of third parties.

   The patent positions of pharmaceutical and biotechnology companies,
including us, are generally uncertain and involve complex legal, scientific and
factual questions.

Our success depends in significant part on our ability to:

  . obtain patents;

  . protect trade secrets;

  . operate without infringing upon the proprietary rights of others; and

  . prevent others from infringing on our proprietary rights.

   Patents may not issue from any of the patent applications that we own or
license. If patents do issue, the allowed claims may not be sufficiently broad
to protect our technology. In addition, issued patents that we own

                                       10


or license may be challenged, invalidated or circumvented. Our patents also may
not afford us protection against competitors with similar technology. Because
patent applications in the United States have been maintained in secrecy until
patents issue, third parties may have filed or maintained patent applications
for technology used by us or covered by our pending patent applications without
our being aware of these applications.

   We may not hold proprietary rights to some patents related to our proposed
products. In some cases, these patents may be owned or controlled by third
parties. As a result, we or our collaborative partners may be required to
obtain licenses under third-party patents to develop and commercialize some of
our proposed products or services. If licenses are not available to us on
acceptable terms, we or our collaborative partners will not be able to develop
and commercialize these products or services.

   If we are not able to keep our trade secrets confidential, our technology
and information may be used by others to compete against us.

   We also rely significantly upon unpatented proprietary technology,
information, processes and know-how. We seek to protect this information
through confidentiality agreements with our employees, consultants and other
third-party contractors as well as through other security measures. These
confidentiality agreements may be breached, and we may not have adequate
remedies for any such breach. In addition, our trade secrets may otherwise
become known or be independently developed by competitors.

   We may become involved in expensive patent litigation or other intellectual
property proceedings which could result in liability for damages or stop our
development and commercialization efforts.

   There have been substantial litigation and other proceedings regarding the
complex patent and other intellectual property rights in the pharmaceutical and
biotechnology industries. We may become a party to patent litigation or other
proceedings regarding intellectual property rights.

   Situations in which we may become involved in patent litigation or other
intellectual property proceedings include:

  . initiation of litigation or other proceedings against third parties to
    enforce our patent rights;

  . initiation of litigation or other proceedings against third parties to
    seek to invalidate the patents held by these third parties or to obtain a
    judgment that our products or services do not infringe the third parties'
    patents;

  . participation in interference or opposition proceedings to determine the
    priority of invention if our competitors file patent applications that
    claim technology also claimed by us;

  . initiation of litigation by third parties claiming that our processes or
    products or the intended use of our products infringe their patent or
    other intellectual property rights; and

  . initiation of litigation by us or third parties seeking to enforce
    contract rights relating to intellectual property which may be important
    to our business.

   The cost to us of any patent litigation or other proceeding, even if
resolved in our favor, could be substantial. Some of our competitors may be
able to sustain the cost of such litigation or proceedings more effectively
than we can because of their substantially greater financial resources. If a
patent litigation or other intellectual property proceeding is resolved
unfavorably to us, we or our collaborative partners may be enjoined from
manufacturing or selling our products and services without a license from the
other party and be held liable for significant damages. Moreover, we may not be
able to obtain required licenses on commercially acceptable terms or any terms
at all, and we could be liable for lost profits if we are found to infringe a
valid patent, and treble damages if we are found to have willfully infringed
such patent rights. Patent cases

                                       11


frequently involve highly complex scientific matters, and each party has the
right to seek a trial by jury. Accordingly, litigation results are highly
unpredictable and we or our collaborative partners may not prevail in any
patent proceeding.

   Uncertainties resulting from the initiation and continuation of patent
litigation or other proceedings could damage our ability to compete in the
marketplace. Patent litigation and other proceedings may also absorb
significant management time and expense.

   If we breach any of the agreements under which we license or acquire
intellectual property from others, we could lose intellectual property rights
that are important to our business.

   We are a party to intellectual property licenses and agreements that are
important to our business and expect to enter into similar licenses and
agreements in the future. These licenses and agreements impose various
research, development, commercialization, sublicensing, royalty,
indemnification, insurance and other obligations on us. If we fail to comply
with these requirements, we could lose intellectual property rights that are
important to our business.

   If licensees or assignees of our intellectual property rights breach any of
the agreements under which we have licensed or assigned our intellectual
property to them, we could be deprived of important intellectual property
rights and future revenue.

   We are a party to intellectual property out-licenses, collaborations and
agreements that are important to our business and expect to enter into similar
agreements with third parties in the future. Under these agreements, we license
or transfer intellectual property to third parties and impose various research,
development, commercialization, sublicensing, royalty, indemnification,
insurance, and other obligations on them. If a third party fails to comply with
these requirements, we generally retain the right to terminate the agreement,
and to bring a legal action in court or in arbitration. With respect to the
agreement with Stryker regarding OP-1 and agreement with Micromet regarding our
single chain antibody technology, the assignment of intellectual property is
irrevocable in the event of a breach of the agreement. Accordingly, it may be
more difficult to enforce our rights under these agreements in the absence of
litigation.

Risks Related to Our Common Stock

   We expect that our stock price will fluctuate significantly.

   Our common stock is listed on the Nasdaq National Market under the ticker
symbol "CRIS." The stock market, particularly in recent years, has experienced
significant volatility particularly with respect to biopharmaceutical and
biotechnology based stocks. The volatility of biopharmaceutical and
biotechnology based stocks often does not relate to the operating performance
of the companies represented by the stock. Factors that could cause such
volatility in the market price of the common stock include:

  . announcements of the introduction of new products by us or our
    competitors;

  . market conditions in the biotechnology sectors;

  . rumors relating to us or our competitors;

  . litigation or public concern about the safety of our potential products;

  . actual or anticipated variations in our quarterly operating results;

  . deviations in our operating results from the estimates of securities
    analysts;

  . adverse results or delays in clinical trials;


                                       12


  . FDA or international regulatory actions; and

  . general market conditions.

   If stockholders do not receive dividends, stockholders must rely on stock
appreciation for any return on their investment in us.

   We have not declared or paid cash dividends on any of our capital stock. We
currently intend to retain earnings, if any, for future growth and, therefore,
do not anticipate paying cash dividends in the future. As a result, only
appreciation of the price of the common stock will provide a return to
investors.

   We have anti-takeover defenses that could delay or prevent an acquisition
and could adversely affect our stock price.

   Provisions of our certificate of incorporation, our bylaws and Delaware law
may have the effect of deterring unsolicited takeovers or delaying or
preventing changes in control of our management, including transactions in
which our stockholders might otherwise receive a premium for their shares over
then current market prices. In addition, these provisions may limit the ability
of stockholders to approve transactions that they may deem to be in their best
interest. Our certificate of incorporation permits the board of directors to
issue preferred stock without stockholder approval. In addition to delaying or
preventing an acquisition, the issuance of a substantial number of preferred
shares could adversely affect the price of the common stock.

   Our certificate of incorporation provides for staggered terms to be served
by the board of directors which makes it difficult for stockholders to change
the composition of the board of directors in any one year. In addition, our
bylaws restrict the ability of stockholders to call a special meeting of the
stockholders. These provisions may have the effect of preventing or delaying
changes in control of our management.

                                       13


              SPECIAL NOTE REGARDING FORWARD-LOOKING INFORMATION

   This prospectus includes and incorporates forward-looking statements within
the meaning of Section 27A of the Securities Act and Section 21E of the
Securities Exchange Act. All statements, other than statements of historical
facts, included or incorporated in this prospectus regarding our strategy,
future operations, financial position, future revenues, projected costs,
prospects, plans and objectives of management are forward-looking statements.
The words "anticipates," "believes," "estimates," "expects," "intends," "may,"
"plans," "projects," "will," "would" and similar expressions are intended to
identify forward-looking statements, although not all forward-looking
statements contain these identifying words. We cannot guarantee that we
actually will achieve the plans, intentions or expectations disclosed in our
forward-looking statements and you should not place undue reliance on our
forward-looking statements. Actual results or events could differ materially
from the plans, intentions and expectations disclosed in the forward-looking
statements we make. We have included important factors in the cautionary
statements included or incorporated in this prospectus, particularly under the
heading "Risk Factors", that we believe could cause actual results or events
to differ materially from the forward-looking statements that we make. Our
forward-looking statements do not reflect the potential impact of any future
acquisitions, mergers, dispositions, joint ventures or investments we may
make. We do not assume any obligation to update any of our forward-looking
statements.

                                USE OF PROCEEDS

   We will not receive any proceeds from the sale of shares of our common
stock by the selling stockholders.


                                      14


                              SELLING STOCKHOLDERS

   We are registering all 5.2 million shares covered by this prospectus on
behalf of the selling stockholders named in the table below. We issued all of
the shares to the selling stockholders in December 2000 in a private placement
pursuant to purchase agreements signed in November 2000. We have registered the
shares to permit the selling stockholders and their pledgees, donees,
transferees or other successors-in-interest that receive their shares from the
selling stockholders as gifts, partnership distributions or other non-sale
related transfers after the date of this prospectus to resell the shares when
they deem appropriate.

   The following table sets forth the name of each of the selling stockholders,
the number of shares owned by each of the selling stockholders as of July 31,
2001, the number of shares that may be offered under this prospectus, and the
number of shares of common stock to be owned by each of the selling
stockholders after this offering is completed. Percentage of ownership is based
on 32,216,261 shares of common stock outstanding on July 31, 2001. The number
of shares in the column "Number of Shares Being Offered" represent all of the
shares that each selling stockholder may offer under this prospectus.



                          Shares of Common Stock                     Shares of Common Stock to
                               Owned as of                                 be Owned After
                              July 31, 2001         Number of Shares       the Offering**
                          ---------------------------  of Common     ------------------------------
Name of Selling                                       Stock Being
Stockholder                 Number      Percentage   Offered Hereby     Number        Percentage
- ---------------           ------------- ---------------------------- --------------- --------------
                                                                      
Ashton Partners
 L.L.C. ................            --          --          --                   --            --
BayStar Capital, LP.....        168,750          *      168,750                  --            --
BayStar International,
 LTD. ..................         56,250          *       56,250                  --            --
Bridgewood Capital
 Partners, LP...........            --          --          --                   --            --
Carmignac Technologies
 Fund...................            --          --          --                   --            --
Crestwood Capital
 International, Ltd. ...            --          --          --                   --            --
Crestwood Capital
 Partners, LP...........            --          --          --                   --            --
Crestwood Capital
 Partners II, LP........            --          --          --                   --            --
DAS Consulting Inc. ....          5,000          *        5,000                  --            --
The DCF Life Sciences
 Fund Limited...........        185,000          *      100,000               85,000            *
DCF Partners, L.P. .....        350,000        1.1%     300,000               50,000            *
Deephaven Private
 Placement Trading,
 Ltd. ..................            --          --          --                   --            --
DWS Investment..........        425,000        1.3%     425,000                  --            --
Equity Portfolio, a
 series of IDS Life
 Series Fund, Inc. .....            --          --          --                   --            --
Essex Global Life
 Sciences Fund..........            --          --          --                   --            --
Essex Global Life
 Sciences Fund II, LP...            --          --          --                   --            --
Essex Woodlands Health
 Ventures Fund IV,
 L.P. ..................        745,085        2.3%     175,000              570,085          1.8%
The FMG Bio-Med Hedge
 Fund, Ltd. ............            --          --          --                   --            --
Framlington Health
 Fund...................        400,000        1.2%     400,000                  --            --
James C. Kelly..........            --          --          --                   --            --
KCM Biomedical L.P. ....            --          --          --                   --            --
KCM Biomedical Offshore
 Fund, Ltd. ............            --          --          --                   --            --
Meriken Nominees Ltd. ..            --          --          --                   --            --
Moore Global
 Investments, Ltd. .....            --          --          --                   --            --
MRM Life Ltd. ..........            --          --          --                   --            --
Munder Framlington
 Health Fund............        400,000        1.2%     400,000                  --            --
Narragansett I, LP......            --          --          --                   --            --
Narragansett Offshore,
 Ltd. ..................            --          --          --                   --            --
Permal Essex Global
 Healthcare Ltd. .......            --          --          --                   --            --
Remington Investment
 Strategies, L.P. ......            --          --          --                   --            --
UBS O'Connor LLC f/b/o
 UBS Global Arbitrage
 Master Limited.........            --          --          --                   --            --
United Capital
 Management, Inc. ......            --          --          --                   --            --
Veredus Market Neutral
 Fund L.P. .............            --          --          --                   --            --
Veredus Partners L.P....            --          --          --                   --            --
Vulcan Ventures Inc. ...      2,318,663        7.2%     750,000            1,568,663          4.9%
Zeke, LP................            --          --          --                   --            --

- --------
*  Less than one percent.
** Assumes, for purposes of this table, all shares offered pursuant to this
   prospectus are actually sold.

                                       15


   We do not know when or in what amounts a selling stockholder may offer
shares for sale. The selling stockholders may not sell any or all of the shares
offered by this prospectus. Because the selling stockholders may offer all or
some of the shares pursuant to this offering, and because there are currently
no agreements, arrangements or understandings with respect to the sale of any
of the shares, we cannot estimate the number of the shares that will be held by
the selling stockholders after completion of the offering. However, for
purposes of this table, we have assumed that, after completion of the offering,
none of the shares covered by this prospectus will be held by the selling
stockholders.

   Except for Vulcan Ventures Inc., none of the selling stockholders named
above has held any position or office with, or has otherwise had a material
relationship with, us or any of our subsidiaries within the past three years.
Ms. Kunath, a director of Curis since February 2000, has served as
biotechnology portfolio manager for Vulcan Ventures since 1992.

                              PLAN OF DISTRIBUTION

   The selling stockholders may sell the shares from time to time. The selling
stockholders will act independently of us in making decisions regarding the
timing, manner and size of each sale. The sales may be made through the
automated quotation system of the Nasdaq National Market on the facilities of
any national exchanges on which the common stock is then traded or, at prices
and at terms then prevailing or at prices related to the then current market
price, or in privately negotiated transactions. The selling stockholders may
effect these transactions by selling the shares to or through broker-dealers.
The shares may be sold by one or more of, or a combination of, the following:

  . a block trade in which the broker-dealer will attempt to sell the shares
    as agent but may position and resell a portion of the block as principal
    to facilitate the transaction;

  . purchases by a broker-dealer as principal and resale by a broker-dealer
    for its account under this prospectus;

  . an exchange distribution in accordance with the rules of an exchange;

  . ordinary brokerage transactions and transactions in which the broker
    solicits purchasers; and

  . in privately negotiated transactions.

   To the extent required, this prospectus may be amended or supplemented from
time to time to describe a specific plan of distribution. If the plan of
distribution involves an arrangement with a broker-dealer for the sale of
shares through a block trade, special offering, exchange distribution or
secondary distribution or a purchase by a broker or dealer, the amendment or
supplement will disclose:

  . the name of each selling stockholder and of the participating broker-
    dealer(s);

  . the number of shares involved;

  . the price at which the shares were sold;

  . the commissions paid or discounts or concessions allowed to the broker-
    dealer(s), where applicable;

  . that a broker-dealer(s) did not conduct any investigation to verify the
    information set out or incorporated by reference in this prospectus; and

  . other facts material to the transaction.

   From time to time, a selling stockholder may transfer, pledge, donate or
assign its shares of common stock to lenders or others and each of such persons
will be deemed to be a "selling stockholder" for purposes of this prospectus.
The number of shares of common stock beneficially owned by the selling
stockholder will decrease as and when it takes such actions. The plan of
distribution for the selling stockholders' shares of common stock sold under
this prospectus will otherwise remain unchanged, except that the transferees,
pledgees, donees or

                                       16


other successors will be selling stockholders hereunder. The selling
stockholders may enter into hedging transactions with broker-dealers in
connection with distributions of the shares or otherwise. In these
transactions, broker-dealers may engage in short sales of the shares in the
course of hedging the positions they assume with selling stockholders. The
selling stockholders also may sell shares short and redeliver the shares to
close out short positions.

   The selling stockholders may enter into option or other transactions with
broker-dealers which require the delivery to the broker-dealer of the shares.
The broker-dealer may then resell or otherwise transfer the shares under this
prospectus. The selling stockholders also may loan or pledge the shares to a
broker-dealer. The broker-dealer may sell the loaned shares, or upon a default
the broker-dealer may sell the pledged shares under this prospectus.

   In effecting sales, broker-dealers engaged by the selling stockholders may
arrange for other broker-dealers to participate in the resales. Broker-dealers
or agents may receive compensation in the form of commissions, discounts or
concessions from selling stockholders. Broker-dealers or agents may also
receive compensation from the purchasers of the shares for whom they act as
agents or to whom they sell as principals, or both. Compensation as to a
particular broker-dealer might be in excess of customary commissions and will
be in amounts to be negotiated in connection with the sale. Broker-dealers or
agents and any other participating broker-dealers or the selling stockholders
may be deemed to be "underwriters" within the meaning of Section 2(11) of the
Securities Act in connection with sales of the shares. Accordingly, any
commission, discount or concession received by them and any profit on the
resale of the shares purchased by them may be deemed to be underwriting
discounts or commissions under the Securities Act. Because selling stockholders
may be deemed to be "underwriters" within the meaning of Section 2(11) of the
Securities Act, the selling stockholders will be subject to the prospectus
delivery requirements of the Securities Act. In addition, any securities
covered by this prospectus that qualify for sale under Rule 144 promulgated
under the Securities Act may be sold under Rule 144 rather than under this
prospectus. The selling stockholders have advised us that they have not entered
into any agreements, understandings or arrangements with any underwriters or
broker-dealers regarding the sale of their securities. There is no underwriter
or coordinating broker acting in connection with the proposed sale of shares by
the selling stockholders.

   The shares will be sold only through registered or licensed brokers or
dealers if required under applicable state securities laws. In addition, in
some states the shares may not be sold unless they have been registered or
qualified for sale in the applicable state or an exemption from the
registration or qualification requirement is available and is complied with.

   Under applicable rules and regulations under the Exchange Act any person
engaged in the distribution of the shares may not simultaneously engage in
market making activities with respect to our common stock for a period of two
business days prior to the commencement of the distribution. In addition, each
selling stockholder will be subject to applicable provisions of the Exchange
Act and the associated rules and regulations under the Exchange Act, including
Regulation M, which provisions may limit the timing of purchases and sales of
shares of our common stock by the selling stockholders. We will make copies of
this prospectus available to the selling stockholders and have informed them of
the need to deliver copies of this prospectus to purchasers at or prior to the
time of any sale of the shares.

   We will bear all costs, expenses and fees in connection with the
registration of the shares. The selling stockholders will bear all commissions
and discounts, if any, attributable to the sales of the shares. The selling
stockholders may agree to indemnify any broker-dealer or agent that
participates in transactions involving sales of the shares against specific
liabilities, including liabilities arising under the Securities Act. The
selling stockholders have agreed to indemnify specific persons, including
broker-dealers and agents, against specific liabilities in connection with the
offering of the shares, including liabilities arising under the Securities Act.

   We have agreed to maintain the effectiveness of this registration statement
until the earlier of 24 months from the effective date or the date on which the
shares purchased in the private placement may be resold without registration by
reason of Rule 144(k) promulgated under the Securities Act. The selling
stockholders may sell all, part or none of the shares offered by this
prospectus.

                                       17


                                 LEGAL MATTERS

   The validity of the shares of our common stock offered by this prospectus
were passed upon for us by Hale and Dorr LLP, Boston, Massachusetts.

                                    EXPERTS

   The consolidated financial statements incorporated in this prospectus by
reference to the Annual Report on Form 10-K of Curis for the year ended
December 31, 2000 have been so incorporated in reliance upon the report of
Arthur Andersen LLP, independent public accountants, given on the authority of
said firm as experts on auditing and accounting.

   The consolidated financial statements of Creative BioMolecules, Inc.,
predecessor to Curis, as of December 31, 1999 and for each of the two years in
the period ended December 31, 1999 incorporated in this prospectus by reference
to the Annual Report on Form 10-K of Curis for the year ended December 31,
2000, as filed with the Securities and Exchange Commission on March 30, 2001,
have been audited by Deloitte & Touche LLP, independent auditors, as stated in
their report (which report expresses an unqualified opinion and includes an
emphasis paragraph referring to the merger agreement with Ontogeny, Inc. and
Reprogenesis, Inc. to form Curis), and have been so incorporated in reliance
upon the report of such firm given upon their authority as experts in
accounting and auditing.

                             ADDITIONAL INFORMATION

   We have filed with the Securities and Exchange Commission a Registration
Statement on Form S-3 under the Securities Act with respect to the common stock
offered by this prospectus. This prospectus, which is a part of the
registration statement, does not contain all of the information set forth in
the registration statement. For further information about us and the common
stock offered by this prospectus, we refer you to the registration statement
and the exhibits and schedules filed as a part of the registration statement.
Statements contained in this prospectus as to the contents of any contract or
other document filed as an exhibit to the registration statement are not
necessarily complete. If a contract or document has been filed as an exhibit to
the registration statement, we refer you to the copy of the contract or
document that has been filed. The registration statement, including exhibits,
may be inspected without charge at the principal office of the Commission in
Washington, D.C. and copies of all or any part of which may be inspected and
copied at the public reference facilities maintained by the Commission at 450
Fifth Street, N.W., Judiciary Plaza, Room 1024, Washington, D.C. 20549, and at
the Commission regional offices located at Citicorp Center, 500 West Madison
Street, Suite 1400, Chicago, Illinois 60661-2511 and 7 World Trade Center,
Suite 1300, New York, New York 10048. Copies of such material can also be
obtained at prescribed rates by mail from the Public Reference Section of the
Commission at 450 Fifth Street, N.W., Washington, D.C. 20549. You may obtain
information on the operation of the public reference room by calling the
Commission at 1-800-SEC-0330. In addition, the Commission maintains a website
at http://www.sec.gov that contains reports, proxy and information statements
and other information regarding registrants that file electronically with the
Commission.

   We are subject to the information and reporting requirements of the
Securities Exchange Act of 1934, as amended, and, in accordance therewith, we
are required to file annual and quarterly reports, proxy statements and other
information with the Commission. These reports, proxy statements and other
information are available for inspection and copying at the Commission public
reference rooms and the Commission's website referred to above.

                      WHERE YOU CAN FIND MORE INFORMATION

   We file annual, quarterly and special reports, proxy statements and other
information with the Securities and Exchange Commission. You may review any
document we file at the Commission's public reference room at Judiciary Plaza,
450 Fifth Street, N.W., Washington, D.C. 20549 or Seven World Trade Center,
13th Floor,

                                       18


New York, New York 10048 or Citicorp Center, 500 West Madison Street, Suite
1400, Chicago, Illinois 60661. Please call the Commission at 1-800-SEC-0330 for
further information on the operation of the public reference rooms. Our
Commission filings can also be reviewed by accessing the Commission's internet
site at http://www.sec.gov, which contains reports, proxy and information
statements and other information regarding registrants that file electronically
with the Commission.

   You should rely only on the information or representations provided in this
prospectus. We have not authorized anyone to provide you with different
information. We are not making an offer of the common stock covered by this
prospectus in any state where the offer is not permitted. You should not assume
that the information in this prospectus is accurate as of any date other than
the date on the front of the document.

                INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

   The SEC allows us to "incorporate" into this prospectus information that we
file with the SEC in other documents. This means that we can disclose important
information to you by referring to other documents that contain that
information. The information incorporated by reference is considered to be part
of this prospectus. Information contained in this prospectus and information
that we file with the SEC in the future and incorporated by reference in this
prospectus automatically updates and supersedes previously filed information.
We incorporate by reference the documents listed below and any future filings
we made with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Securities
Exchange Act of 1934, prior to the sale of all the shares of common stock
covered by this prospectus.

   (1) Our Annual Report on Form 10-K for the year ended December 31, 2000,

   (2) Our Quarterly Report on Form 10-Q for the quarter ended March 31, 2001,

   (3) Our Current Report on Form 8-K filed on January 31, 2001,

   (4) Our Current Report on Form 8-K filed on July 2, 2001,

   (5) Our Current Report on Form 8-K filed on July 5, 2001,

   (6) All of our filings pursuant to the Exchange Act after the date of filing
the initial registration statement and prior to the effectiveness of the
registration statement, and

   (7) The description of our common stock contained in our Registration
Statement on Form 8-A declared effective on June 19, 2000.

   You may request a copy of these documents, which will be provided to you at
no cost, by contacting:

                     Curis, Inc.
                     61 Moulton Street
                     Cambridge, MA 02138
                     Attention: George A. Eldridge
                     Telephone: (617) 503-6500


                                       19


                PART II. INFORMATION NOT REQUIRED IN PROSPECTUS

Item 14. Other Expenses of Issuance and Distribution.

   The following table sets forth the various expenses to be incurred in
connection with the sale and distribution of the securities being registered
hereby, all of which will be borne by the Registrant (except any commissions
and expenses incurred by the selling stockholders for brokerage, accounting,
tax or legal services or any other expenses incurred by the selling
stockholders in disposing of the shares). All amounts shown are estimates
except the Securities and Exchange Commission registration fee.


                                                                 
   Filing Fee--Securities and Exchange Commission.................. $ 13,825.00
   Legal fees and expenses.........................................  100,000.00
   Accounting fees and expenses....................................   65,000.00
   Printing, EDGAR formatting and mailing expenses.................   50,000.00
   Miscellaneous expenses..........................................   13,175.00
                                                                    -----------
     Total expenses................................................ $242,000.00
                                                                    ===========


Item 15. Indemnification of Directors and Officers.

   Article SIXTH of the Registrant's Certificate of Incorporation provides, in
general, that no director shall be personally liable to the Registrant or to
any of its stockholders for monetary damages arising out of such director's
breach of fiduciary duty as a director of the registrant, except to the extent
that the elimination or limitation of such liability is not permitted by the
General Corporation Law of the State of Delaware ("Delaware Corporation Law"),
as the same exists or may hereafter be amended.

   Article EIGHTH of the Registrant's Certificate of Incorporation provides, in
general, that the Registrant shall indemnify each person who was or is a party
or is threatened to be made a party to any threatened, pending or completed
action, suit or proceeding, whether civil, criminal, administrative or
investigative (other than an action by or in the right of the registrant), by
reason of the fact that such person is or was, or has agreed to become, a
director or officer of the registrant, or is or was serving or has agreed to
serve, at the request of the Registrant, as a director, officer or trustee of,
or in a similar capacity with, another corporation (including any partially or
wholly owned subsidiary of the registrant), partnership, joint venture, trust
or other enterprise (including any employee benefit plan), against expenses
(including attorneys' fees), judgments, fines and amounts paid in settlement
actually and reasonably incurred in connection with any such action, suit or
proceeding to the maximum extent permitted by the Delaware Corporation Law and
further provides that the foregoing right of indemnification shall in no way be
exclusive of any other rights of indemnification to which any such director or
officer may be entitled, under any by-law, agreement, vote of directors or
stockholders or otherwise.

   Section 145(a) of the Delaware Corporation Law provides, in general, that a
corporation shall have the power to indemnify any person who was or is a party
or is threatened to be made a party to any threatened, pending or completed
action, suit or proceeding, whether civil, criminal, administrative or
investigative (other than an action by or in the right of the corporation),
because the person is or was a director or officer of the corporation. Such
indemnity may be against expenses (including attorneys' fees), judgments, fines
and amounts paid in settlement actually and reasonably incurred by the person
in connection with such action, suit or proceeding, if the person acted in good
faith and in a manner the person reasonably believed to be in or not opposed to
the best interests of the corporation and if, with respect to any criminal
action or proceeding, the person did not have reasonable cause to believe the
person's conduct was unlawful.

   Section 145(b) of the Delaware Corporation Law provides, in general, that a
corporation shall have the power to indemnify any person who was or is a party
or is threatened to be made a party to any threatened, pending or completed
action or suit by or in the right of the corporation to procure a judgment in
its favor

                                      II-1


because the person is or was a director or officer of the corporation, against
any expenses (including attorneys' fees) actually and reasonably incurred by
the person in connection with the defense or settlement of such action or suit
if the person acted in good faith and in a manner the person reasonably
believed to be in or not opposed to the best interests of the corporation.

   Section 145(g) of the Delaware Corporation Law provides, in general, that a
corporation shall have the power to purchase and maintain insurance on behalf
of any person who is or was a director or officer of the corporation against
any liability asserted against the person in any such capacity, or arising out
of the person's status as such, whether or not the corporation would have the
power to indemnify the person against such liability under the provisions of
the law.

Item 16. Exhibits.



 Exhibit
 Number  Description
 ------- -----------
      
   3.1   Restated Certificate of Incorporation of Curis, Inc. (previously filed
         as an exhibit to the Joint Proxy Statement Prospectus on Form S-4 of
         Curis, Inc. (File No. 333-32446) and incorporated herein by
         reference).

   3.2   Certificate of Designations of Curis, Inc.

   3.3   Amended and Restated By-laws of Curis, Inc. (previously filed as an
         exhibit to the Registration Statement on Form S-1 of Curis, Inc. (File
         No. 333-50906) and incorporated herein by reference).

   5.1   Opinion of Hale and Dorr LLP (previously filed as an exhibit to the
         Registration Statement on Form S-1 of Curis, Inc. (File No. 333-50906)
         and incorporated herein by reference).

  23.1   Consent of Arthur Andersen LLP.

  23.2   Consent of Deloitte & Touche LLP.

  23.3   Consent of Hale and Dorr LLP, included in Exhibit 5.1 filed herewith
         (previously filed as an exhibit to the Registration Statement on Form
         S-1 of Curis, Inc. (File No. 333-50906) and incorporated herein by
         reference).


                                      II-2


Item 17. Undertakings.

   Item 512(a) of Regulation S-K. The undersigned Registrant hereby undertakes:

   (1) To file, during any period in which offers or sales are being made, a
post-effective amendment to this Registration Statement:

     (i) To include any prospectus required by Section 10(a)(3) of the
  Securities Act of 1933, as amended (the "Securities Act");

     (ii) To reflect in the prospectus any facts or events arising after the
  effective date of this Registration Statement (or the most recent post-
  effective amendment thereof) which, individually or in the aggregate,
  represent a fundamental change in the information set forth in this
  Registration Statement. Notwithstanding the foregoing, any increase or
  decrease in the volume of securities offered (if the total dollar value of
  securities offered would not exceed that which was registered) and any
  deviation from the low or high end of the estimated maximum offering range
  may be reflected in the form of prospectus filed with the Commission
  pursuant to Rule 424(b) if, in the aggregate, the changes in volume and
  price represent no more that 20 percent change in the maximum aggregate
  offering price set forth in the "Calculation of Registration Fee" table in
  the effective Registration Statement; and

     (ii) To include any material information with respect to the plan of
  distribution not previously disclosed in this Registration Statement or any
  material change to such information in this Registration Statement;

provided, however, that paragraphs (1)(I) and (1)(ii) do not apply if the
information required to be included is a post-effective amendment by this
paragraphs is contained in periodic filed by the Company pursuant to Section 13
or Section 15(d) of the Securities Exchange Act of 1934, as amended (the
"Exchange Act"), that are incorporated by reference in this Registration
Statement.

   (2) That, for the purposes of determining any liability under the Securities
Act, each post-effective amendment that contains a form of prospectus shall be
deemed to be a new registration statement relating to the securities offered
therein, and the offering of such securities at the time shall be deemed to be
the initial bona fide offering thereof.

   (3) To remove from registration by means of a post-effective amendment any
of the securities being registered which remain unsold at the termination of
the offering.

   Item 512(b) of Regulation S-K. The Registrant hereby undertakes that, for
purposes of determining any liability under the Securities Act, each filing of
the Registrant's annual report pursuant to Section 13(a) or 15(d) of the
Exchange Act (and, where applicable, each filing of an employee benefit plan's
annual report pursuant to Section 15(d) of the Exchange Act) that is
incorporated by reference in this Registration Statement shall be deemed to be
a new registration statement relating to the securities offered therein and the
offering of such securities at the time shall be deemed to be the initial bona
fide offering thereof.

   Item 512(h) of Regulation S-K. Insofar as indemnification for liabilities
arising under the Securities Act may be permitted to directors, officers and
controlling persons of the Registrant pursuant to the indemnification
provisions described herein, or otherwise, the Registrant has been advised that
in the opinion of the Securities and Exchange Commission such indemnification
is against public policy as expressed in the Securities Act and is, therefore,
unenforceable. In the event that a claim for indemnification against such
liabilities (other than the payment by the Registrant of expenses incurred or
paid by a director, officer or controlling person of the Registrant in the
successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the Registrant will, unless in the opinion of its counsel the
matter has been settled by controlling precedent, submit to a court of
appropriate jurisdiction the question whether such indemnification by it is
against public policy as expressed in the Securities Act and will be governed
by the final adjudication of such issue.

                                      II-3


                                   SIGNATURES

   Pursuant to the requirements of the Securities Act of 1933, as amended, the
Registrant has duly caused this Post-Effective Amendment No. 1 on Form S-3 to
Registration Statement on Form S-1 to be signed on its behalf by the
undersigned, thereunto duly authorized, in the city of Cambridge, Commonwealth
of Massachusetts, on August 10, 2001.

                                          Curis, Inc.

                                          By:  /s/ Doros Platika
                                             ----------------------------------
                                          Name: Doros Platika
                                          Title: President and Chief Executive
                                           Officer


                                      II-4


   Pursuant to the requirements of the Securities Act of 1933, this Post-
Effective Amendment No. 1 on Form S-3 to Registration Statement on Form S-1 has
been signed by the following persons in the capacities and on the dates
indicated.



              Signature                          Title                   Date
              ---------                          -----                   ----

                                                            
          /s/ Doros Platika            Chief Executive Officer      August 10, 2001
______________________________________  (principal executive
            Doros Platika               officer)
                                        and Director

                  *                    Vice President and Chief     August 10, 2001
______________________________________  Financial Officer
          George A. Eldridge            (principal financial and
                                        accounting officer)

                  *                    Director                     August 10, 2001
______________________________________
            Susan B. Bayh

                  *                    Director                     August 10, 2001
______________________________________
         Martyn D. Greenacre

                  *                    Director                     August 10, 2001
______________________________________
            Ruth B. Kunath

                  *                    Director                     August 10, 2001
______________________________________
         James R. McNab, Jr.

                  *                    Director                     August 10, 2001
______________________________________
          Douglas A. Melton

                  *                    Director                     August 10, 2001
______________________________________
          Michael Rosenblatt

                  *                    Director                     August 10, 2001
______________________________________
            James R. Tobin




                                                            
          /s/ Doros Platika                                         August 10, 2001
______________________________________
  Doros Platika, as Attorney-in-Fact



                                      II-5


                                 EXHIBIT INDEX



 Exhibit
 Number  Description
 ------- -----------
      
   3.1   Restated Certificate of Incorporation of Curis, Inc. (previously filed
         as an exhibit to the Joint Proxy Statement Prospectus on Form S-4 of
         Curis, Inc. (File No. 333-32446) and incorporated herein by
         reference).

   3.2   Certificate of Designations of Curis, Inc.

   3.3   Amended and Restated By-laws of Curis, Inc. (previously filed as an
         exhibit to the Registration Statement on Form S-1 of Curis, Inc. (File
         No. 333-50906) and incorporated herein by reference).

   5.1   Opinion of Hale and Dorr LLP (previously filed as an exhibit to the
         Registration Statement on Form S-1 of Curis, Inc. (File No. 333-50906)
         and incorporated herein by reference).

  23.1   Consent of Arthur Andersen LLP.

  23.2   Consent of Deloitte & Touche LLP.

  23.3   Consent of Hale and Dorr LLP, included in Exhibit 5.1 filed herewith
         (previously filed as an exhibit to the Registration Statement on Form
         S-1 of Curis, Inc. (File No. 333-50906) and incorporated herein by
         reference).