SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

                                    FORM 10-Q

            [X] QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF
                      THE SECURITIES EXCHANGE ACT OF 1934

                For the quarterly period ended September 30, 1998

                                       OR

            [ ] TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF
                       THE SECURITIES EXCHANGE ACT OF 1934

   For the transition period from ____________________ to ____________________

                         Commission File Number 0-14656

                              REPLIGEN CORPORATION
             (exact name of registrant as specified in its charter)

               Delaware                                          04-2729386
     (State or other jurisdiction of                          (I.R.S. Employer
    incorporation or organization)                           Identification No.)

           117 Fourth Avenue
         Needham, Massachusetts                                     02494
(Address of principal executive offices)                          (Zip Code)

       Registrant's telephone number, including area code: (781)-449-9560

 ------------------------------------------------------------------------------
(Former name, former address and former fiscal year, if changed since last
report.)

Indicate by check mark whether the registrant (1) has filed all reports required
to be filed by Section 13 or 15 (d) of the Securities Exchange Act of 1934
during the preceding 12 months (or for such shorter period that the registrant
was required to file such reports), and (2) has been subject to such filing
requirements for the past 90 days. Yes [X]   No    .
                                       ---     ---

Indicate the number of shares outstanding of each of the issuer's classes of
common stock, as of October 31, 1998.

Common Stock, par value $.01 per share                           18,001,785
- --------------------------------------                        ----------------
            Class                                             Number of Shares




                              REPLIGEN CORPORATION

                                      INDEX



                                                                                                        PAGE
                                                                                                        ----
                          PART I. FINANCIAL INFORMATION
                                                                                                   

Item 1.  Financial Statements

         Condensed Consolidated Balance Sheets as of September 30, 1998 and
         March 31, 1998                                                                                   3

         Condensed Consolidated Statements of Operations for the Three and Six Months
         Ended September 30, 1998 and 1997                                                                4

         Condensed Consolidated Statement of Cash Flows for the Six Months Ended
         September 30, 1998 and 1997                                                                      5

         Notes to Condensed Consolidated Financial Statements                                             6

Item 2.  Management's Discussion and Analysis of Financial Condition and Results
             of Operations                                                                                7

                      PART II. OTHER INFORMATION

Item 1.  Legal Proceedings                                                                               10

Item 2.  Changes in Securities
         None

Item 3.  Defaults Upon Senior Securities
         None

Item 4.  Submissions of Matters to a Vote of Security Holders                                            11

Item 5.  Other Information
         None

Item 6.  Exhibits and Reports on Form 8-K                                                                11

    (a)  Exhibits

         27.1              Financial Data Schedule

    (b)  Reports on Form 8-K
         None

Signature                                                                                                12

Exhibit Index                                                                                            13

Exhibits                                                                                                 14



                                       2


PART I. FINANCIAL INFORMATION

ITEM I. FINANCIAL STATEMENTS

                              REPLIGEN CORPORATION
                      CONDENSED CONSOLIDATED BALANCE SHEETS
                                   (Unaudited)



     ASSETS                                                            September 30, 1998      March 31, 1998
                                                                       ------------------      --------------
                                                                                          
Current assets:
  Cash and cash equivalents                                             $  4,099,874            $  4,725,544
  Accounts receivable                                                        460,719                 212,857
  Inventories                                                                727,495                 670,818
  Prepaid expenses and other current assets                                   77,113                 156,228
                                                                        ------------            ------------
    Total current assets                                                   5,365,201               5,765,447

Property, plant and equipment, at cost:
  Equipment                                                                  810,858                 770,512
  Furniture and fixtures                                                      61,376                  40,563
  Leasehold improvements                                                     460,318                 442,528
                                                                        ------------            ------------
                                                                           1,332,552               1,253,603
  Less: accumulated depreciation and amortization                            726,303                 594,719
                                                                        ------------            ------------
                                                                             606,249                 658,884

Other assets, net                                                             88,472                  88,472
                                                                        ------------            ------------
                                                                        $  6,059,922            $  6,512,803
                                                                        ============            ============


                      LIABILITIES AND STOCKHOLDERS' EQUITY

                                                                                          
Current liabilities:
  Accounts payable                                                      $    111,921            $    100,719
  Accrued expenses                                                           365,498                 254,312
  Unearned income                                                                 --                  33,332
                                                                        ------------            ------------
     Total current liabilities                                               477,419                 388,363
Commitments and contingencies
Stockholders' equity:
  Preferred stock, $.01 par value --
    authorized -- 5,000,000 shares --
    outstanding -- none                                                           --                      --
  Common stock, $.01 par value --
   authorized -- 30,000,000 shares--
   outstanding -- 18,001,785 shares at September
   30, 1998 and March 31, 1998                                               180,017                 180,017
  Additional paid-in capital                                             130,264,048             130,264,048
  Accumulated deficit                                                   (124,861,562)           (124,319,625)
                                                                        ------------            ------------
     Total stockholders' equity                                            5,582,503               6,124,440
                                                                        ------------            ------------

                                                                        $  6,059,922            $  6,512,803
                                                                        ============            ============


          See accompanying notes to consolidated financial statements.


                                       3


                              REPLIGEN CORPORATION
                 CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS
                                   (Unaudited)



                                                   Three Months Ended                      Six Months Ended
                                                   ------------------                      ----------------

                                            September 30,      September 30,       September 30,       September 30,
                                            -------------      -------------       -------------       -------------
                                                1998               1997                1998                1997
                                                ----               ----                ----                ----
                                                                                           
Revenues:
  Research and development                  $     470,032      $     166,085       $    738,438        $    424,369
  Product                                         197,010            257,202            426,149             539,385
  Investment income                                57,491             68,428            119,182             115,106
  Other                                            37,648             11,613             70,836              99,975
                                            -------------      -------------       ------------        ------------
                                                  762,181            503,328          1,354,604           1,178,835
                                            -------------      -------------       ------------        ------------

Costs and expenses:
  Research and development                        464,955            350,544            931,025             714,201
  Selling, general and administrative             354,311            315,352            711,243             622,208
  Cost of products sold                           141,991             79,233            254,273             227,818
                                            -------------      -------------       ------------        ------------
                                                  961,258            745,129          1,896,541           1,564,227
                                            -------------      -------------       ------------        ------------

Net loss                                    $    (199,077)     $    (241,801)      $   (541,937)       $   (385,392)
                                            =============      =============       ============        ============

Basic and diluted net loss per share        $       (0.01)     $       (0.02)      $      (0.03)       $      (0.02)
                                            =============      =============       ============        ============


Basic and diluted weighted average             18,001,785         16,001,785         18,001,785          16,001,785
common shares outstanding                   =============      =============       ============        ============



     See accompanying notes to condensed consolidated financial statements.


                                       4


                              REPLIGEN CORPORATION
                 CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS
                                   (Unaudited)



                                                                    Six Months Ended September 30,
                                                                    ------------------------------
                                                                        1998               1997
                                                                    -----------        -----------
                                                                                 
Cash flows from operating activities:
   Net loss                                                         $  (541,937)       $  (385,392)
   Adjustments to reconcile net loss to net cash
   used in operating activities -
     Depreciation and amortization                                      131,586            120,692
     Compensation charge from stock options                                  --             17,475

Changes in assets and liabilities -
   Accounts receivable                                                 (247,862)           266,388
   Inventories                                                          (56,677)          (110,928)
   Prepaid expenses and other current assets                             79,115             50,129
   Accounts payable                                                      11,202           (104,635)
   Accrued expenses                                                     111,186           (145,972)
   Unearned income                                                      (33,332)          (100,002)
                                                                    -----------        -----------
     Net cash used in operating activities                             (546,719)          (392,245)
                                                                    -----------        -----------
Cash flows from investing activities:
   Decrease in marketable securities                                         --             55,211
   Purchases of property, plant and equipment, net                      (78,951)           (98,667)
   Decrease in restricted cash                                               --             50,087
                                                                    -----------        -----------
      Net cash (used in) provided by investing activities               (78,951)             6,631
                                                                    -----------        -----------

Net decrease in cash and cash equivalents                              (625,670)          (385,614)
Cash and cash equivalents, beginning of period                        4,725,544          3,465,881
                                                                    -----------        -----------
Cash and cash equivalents, end of period                            $ 4,099,874        $ 3,080,267
                                                                    ===========        ===========


          See accompanying notes to consolidated financial statements.


                                       5


                              REPLIGEN CORPORATION
              NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS
                                   (Unaudited)

1.    Basis of Presentation

            The condensed consolidated financial statements included herein have
      been prepared by Repligen Corporation (the "Company" or "Repligen"),
      pursuant to the rules and regulations of the Securities and Exchange
      Commission for quarterly reports on Form 10-Q and do not include all of
      the information and footnote disclosures required by generally accepted
      accounting principles. These financial statements should be read in
      conjunction with the audited financial statements and notes thereto
      included in the Company's Form 10-K for the year ending March 31, 1998.

            In the opinion of management, the accompanying unaudited financial
      statements include all adjustments consisting of only normal, recurring
      adjustments necessary to present fairly, the consolidated financial
      position, results of operations and cash flows. The results of operations
      for the interim periods presented are not necessarily indicative of
      results to be expected for the entire year.

            The preparation of financial statements in conformity with generally
      accepted accounting principles requires management to make estimates and
      assumptions that affect the reported amounts of assets and liabilities and
      disclosure of contingent assets and liabilities at the date of the
      financial statements and the reported amounts of revenues and expenses
      during the reporting period. Actual results could differ from those
      estimates.

2.    Net Loss Per Share

            The Company has adopted Statement of Financial Accounting Standards
      (SFAS) No. 128, Earnings per Share, effective December 15, 1997. SFAS No.
      128 establishes standards for computing and presenting earnings per share
      and applies to entities with publicly held common stock or potential
      common stock. The Company has applied the provisions of SFAS No. 128,
      retroactively to all periods presented. Basic and diluted net loss per
      share represents net loss divided by the weighted average number of common
      shares outstanding during the period. The dilutive effect of the potential
      common shares consisting of outstanding stock options and warrants is
      determined using the treasury stock method in accordance with SFAS No.
      128. Diluted weighted average shares outstanding at September 30, 1998 and
      1997 excluded the potential common shares from warrants and stock options
      because to do so would be antidilutive for the periods presented. At
      September 30, 1998, there are 1,042,000 options outstanding with a
      weighted average exercise price of $1.34 and 2,832,000 warrants
      outstanding with a weighted average exercise price of $3.97.

3.    Cash Equivalents

            The Company accounts for investments in accordance with SFAS No.
      115, Accounting for Certain Investments in Debt and Equity Securities. The
      Company considers all highly liquid investments with a maturity of three
      months or less at the time of acquisition to be cash equivalents. Included
      in cash equivalents at September 30, 1998 and 1997 are $972,000 and
      $280,000 of cash and money market funds and approximately $3,128,000 and
      $2,800,000 of commercial paper, respectively.

4.    Inventories

            Inventories are stated at the lower of cost (first-in, first-out) or
      market and consist of the following:


                                       6




                                                        September 30,            March 31,
                                                            1998                   1998
                                                     -----------------      -----------------
                                                                          
            Raw materials and work-in-process            $ 514,114              $ 388,727
            Finished goods                                 213,381                282,091
                                                         ---------              ---------
                 Total                                   $ 727,495              $ 670,818
                                                         =========              =========


            Work in process and finished goods inventories consist of material,
      labor, outside processing costs and manufacturing overhead.

5.    Comprehensive Income

            Effective January 1, 1998, the Company adopted SFAS No. 130
      Reporting Comprehensive Income, effective January 1, 1998. SFAS No. 130
      establishes standards for reporting and display of comprehensive income
      and its components in financial statements. Comprehensive income includes
      all changes in equity during a period except those resulting from
      investments by owners and distributions to owners. The comprehensive net
      loss is the same as net loss for all periods presented.

6.    New Accounting Standards

            In April 1998, the AICPA issued Statements of Position 98-5
      Reporting on the Costs of Start-up Activities (SOP 98-5). SOP 98-5
      requires all costs associated with the pre-opening, pre-operating and
      organization activities to be expenses as incurred. The Company will adopt
      SOP 98-05 beginning January 1, 1999. Adoption of this statement will not
      have a material impact on the Company's consolidated financial position or
      results of operations.

ITEM 2.   MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND
          RESULTS OF OPERATIONS

Cautionary Statement Regarding Forward-Looking Statements

            Statements in this Quarterly Report on Form 10-Q as well as oral
      statements that may be made by the Company or by officers, directors or
      employees of the Company acting on the Company's behalf, that are not
      historical facts constitute "forward-looking statements" within the
      meaning of the Private Securities Litigation Reform Act of 1997. Such
      forward-looking statements involve known and unknown risks, uncertainties
      and other factors that could cause the actual results of the Company to be
      materially different from the historical results or from any results
      expressed or implied by such forward-looking statements. The Company's
      future operating results are subject to risks and uncertainties and are
      dependent upon many factors, including, without limitation, the Company's
      ability to (i) meet its working capital and future liquidity needs, (ii)
      successfully implement its strategic growth strategies, (iii) understand,
      anticipate and respond to rapidly changing technologies and market trends,
      (iv) develop, manufacture and deliver high quality, technologically
      advanced products on a timely basis to withstand competition from
      competitors which may have greater financial, information gathering and
      marketing resources than the Company, (v) obtain and protect licensing and
      intellectual property rights necessary for the Company's technology and
      product development on terms favorable to the Company, and (vi) recruit
      and retain highly talented professionals in a competitive job market.
      Further information on potential factors that could affect the Company's
      financial results are included in filings made by the Company from time to
      time with the Securities and Exchange Commission included in the section
      entitled "Risk Factors" contained in the Company's Annual Report on Form
      10-K for the fiscal year ended March 31, 1998 (File No.000-14656).


                                       7


Overview

            Repligen Corporation ("Repligen" or the "Company") develops new
      drugs for cancer, organ transplant and autoimmune diseases. The Company
      applies proprietary methods for the synthesis of libraries of chemical
      compounds designed to block or stabilize pharmaceutically important
      interactions between proteins and other macromolecules. To date, this type
      of interaction has only been accessible with complex natural products or
      protein pharmaceuticals both of which are difficult to develop, administer
      to patients and manufacture.

            Repligen is applying its technology to collaborations with
      pharmaceutical company partners and to the discovery of proprietary drug
      leads. The leading proprietary drug discovery program at the Company is
      the development of novel inhibitors of angiogenesis or new blood vessel
      growth which is essential for solid tumor growth and in certain ocular
      diseases. This program is based on the Company's patented, high throughput
      screening assays designed to detect inhibitors of the growth factors which
      drive angiogenesis and proprietary libraries of compounds designed to
      mimic the natural cell surface ligands of these growth factors. In initial
      preclinical studies, a compound identified from these libraries inhibited
      angiogenic growth factors in vitro and in vivo at non-toxic doses.

            The Company has also developed a biopharmaceutical (protein) product
      (CTLA4-Ig) which acts to selectively block unwanted immune responses in
      organ transplant and other diseases. Initial clinical evaluation of this
      product in bone marrow transplant patients has been carried out by
      investigators at the Dana-Farber Cancer Institute. The objective of this
      study is to determine if CTLA4-Ig can block Graft Versus Host Disease
      ("GVHD"), an immune response which can occur when a bone marrow donor is
      genetically "mismatched" with the recipient. The Dana-Farber investigators
      have reported that ex vivo treatment of bone marrow from a genetically
      "mismatched" family member substantially reduced GVHD in eleven bone
      marrow transplant recipients.

            In July 1998, Repligen filed a complaint relating to a United States
      patent which was issued in 1995 to Bristol-Myers Squibb Corporation (see
      Legal Proceedings). The Company believes that the patent which is the
      subject of the lawsuit does not restrict Repligen from developing CTLA4-Ig
      for use in bone marrow transplants. The Company has filed its own patents
      related to compositions of matter and methods of use of CTLA4-Ig.

            Repligen also develops, manufactures and markets products for the
      production of protein pharmaceuticals (biopharmaceuticals) by affinity
      chromatography. The Company currently markets a line of products for the
      production of monoclonal antibodies intended for human clinical use based
      on a recombinant form of Protein A, a naturally occurring affinity ligand.
      The Company believes that its chemical libraries may be the source of
      additional affinity ligands for biopharmaceutical manufacturing.

Results of Operations

Revenues

            Total revenues for the three month period ended September 30, 1998
      and 1997 were approximately $762,000 and $503,000, respectively, an
      increase of approximately $259,000 or 51%. This increase was largely
      attributable to increased research and development revenue. Year to date
      total revenues increased approximately $176,000, or 15%, to $1,355,000 at
      September 30,1998 from September 30,1997.

            Research and development revenues for the three month period ended
      September 30, 1998 were approximately $470,000 compared to $166,000 in the
      comparable fiscal 1998 period. Revenues for


                                       8


      the quarter ended September 30, 1998 also include a licensing fee received
      from Neocrin, Inc. pursuant to an agreement to license certain of
      Repligen's technology. In the first six months of fiscal 1999, the Company
      recorded research and development revenues totaling $738,000 consisting of
      approximately $377,000 from contracted research and development programs
      and $361,000 from licensing arrangements. In the first six months of
      fiscal 1998, the Company recorded research and development revenues
      totaling $424,000 of revenue with approximately $264,000 from contracted
      research and $160,000 from licensing arrangements.

            Product revenues for the three month period ended September 30, 1998
      and 1997 were approximately $197,000 and $257,000, respectively, a
      decrease of $60,000 or 23% in the area of product sales. During fiscal
      1998, the Company had a significant order to supply reagents for
      contracted research.

            Investment income for the three and six month periods ended
      September 30, 1998 were $57,000 and $119,000, respectively, compared with
      $68,000 and $115,00 over the comparable periods in fiscal 1998. An
      increase in higher average funds available for interest is offset by the
      sale of common stock held as an investment that took place during the
      second quarter of fiscal 1998.

            Other revenues for the three month period ended September 30, 1998
      were approximately $38,000 as compared to $12,000 in the comparable period
      ended September 30, 1997. Other revenues for the six month period ended
      September 30, 1998 decreased from the six month period ended September 30,
      1997 primarily due to the sale of equipment held by the Company reported
      as other income in fiscal 1998.

Expenses

            Total expenses for the three month periods ended September 30, 1998
      and 1997 increased approximately $216,000 or 29% to $961,000 from $745,000
      and increased 21% or approximately $333,000 to $1,897,000 from $1,564,000
      for the six months ended September 30, 1998 and 1997, respectively.

            Research and development expenses for the three months ended
      September 30, 1998 and 1997 were approximately $465,000 and $351,000. For
      the first half of fiscal 1999, research and development expenses were
      approximately $931,000, or 30% higher than the comparable period in fiscal
      1998. This increase reflects increased staffing in research and
      development as the Company expands its investment in proprietary drug
      discovery programs.

            Selling, general and administrative expenses for the three and six
      month periods ended September 30, 1998 were approximately $354,000 and
      $711,000, respectively, which reflects an increase of approximately
      $39,000 and $89,000, respectively, from the comparable fiscal 1998 period.
      This increase is attributable to increased costs in patent, legal and
      shareholder services.

            Cost of products sold for the three month and six month periods
      ended September 30, 1998 were approximately $142,000 and $254,000,
      respectively, as compared to $79,000 and $228,000 for the three and six
      month periods ended September 30, 1997. Cost of products sold in the three
      months ended September 30, 1998 and 1997 were 72% and 31% of product
      revenues. This decrease is attributable to a change in product mix of
      protein A and reagent sales. In the six month periods ended September 30,
      1998 and 1997, cost of products sold was 59% and 42%. This increase is
      largely attributable to increased inventory reserves because of increased
      inventory levels and the introduction of new protein A products.

Liquidity and Capital Resources

            The Company's total cash and cash equivalents decreased to
      $4,100,000 at September 30, 1998 from $4,726,000 at March 31, 1998. This
      decrease of $626,000 reflects net losses incurred during the six month
      period ended September 30, 1998 of approximately $542,000, an increase in


                                       9


      accounts receivable of $248,000 and capital expenditures of $79,000 offset
      in part by the increase in accrued expenses of $122,000 and decrease of
      prepaid expenses and other current assets of $79,000. Working capital
      decreased to $4,888,000 at September 30, 1998 from $5,377,000 at March 31,
      1998.

            The Company has entered into agreements with a number of
      collaborative partners and licensees. Under the terms of these agreements,
      generally, the Company may be eligible to receive research support,
      additional milestones or royalty revenue if the focus of these
      collaborations continue to clinical evaluation and commercialization. The
      Company cannot be assured of the continuation of these collaborations and
      any future payments.

            The Company has funded operations primarily with cash derived from
      the sales of its equity securities, revenue derived from research and
      development contracts, product sales and investment income. While the
      Company anticipates that its cost of operations will increase in fiscal
      1999 as it continues to expand its investment in proprietary product
      development, the Company believes it has sufficient cash equivalents and
      marketable securities to satisfy its working capital and capital
      expenditure requirements for the next twenty-four months. Should the
      Company need to secure additional financing to meet its future liquidity
      requirements, there can be no assurances that the Company will be able to
      secure such financing, or that such financing, if available, will be on
      terms favorable to the Company.

Year 2000

            The Company has undertaken an initial review of its information
      technology computer systems and believes that the Year 2000 problem does
      not pose significant operational problems to its information technology
      systems. The majority of the Company's software and computer equipment has
      been purchased within the last five years from third-party vendors who
      have already provided upgrades intended to bring their products into Year
      2000 compliance. The Company has begun to address the small number of
      internal systems that are not yet Year 2000 compliant, and expects full
      compliance by the end of 1999. The Company currently believes that the
      costs of addressing these issues will not have a material adverse impact
      on the Company's financial position.

            The Company has also recently begun interviewing third parties,
      vendors and suppliers of the Company to determine their exposure to Year
      2000 issues, their anticipated risks and responses to those risks. To
      date, those vendors that have been contacted have indicated that their
      hardware or software is or will be Year 2000 compliant in time frames that
      meet the Company's requirement. However, the Company intends to continue
      to assess its exposure to Year 2000 noncompliance on the part of any of
      its material vendors and there can be no assurance that their systems will
      be Year 2000 compliant.

            The Company does not have a contingency plan in the event Year 2000
      compliance cannot be achieved in a timely manner. A contingency plan will
      be developed immediately upon completion of the Company's Year 2000
      compliance assessment.

Item 1.  LEGAL PROCEEDINGS.

            On July 17, 1998, Repligen filed a complaint at the United States
      District Court for the District of Massachusetts in Boston, Massachusetts
      (the "Complaint"). The Complaint relates to a United States patent which
      was issued in 1995 to Bristol-Myers Squibb Corporation (the "BMS Patent")
      which claims a method of treating immune system diseases with CTLA4-Ig.
      The Complaint seeks to correct the inventorship on the BMS Patent and
      seeks unspecified monetary damages. If successful in its claims, a
      licensor of Repligen will be named as an inventor on the BMS Patent which
      will give Repligen and Bristol-Myers Squibb shared rights to the patent.
      There can be no assurances that the litigation will conclude in a result
      beneficial to the Company. The failure of the litigation may restrict the
      Company's ability to commercialize CTLA4-Ig for certain applications.


                                       10


Item 4.  SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS.

            The Company's Annual Meeting of Stockholders (the "Annual Meeting")
      was held on September 10, 1998. At the Annual Meeting, the stockholders of
      the Company: (i) elected five members to the Board of Directors and (ii)
      ratified the selection of Arthur Andersen LLP as the independent auditors
      of the Company for the fiscal year ending March 31, 1999.

            The Company had 18,001,785 shares of Common Stock of the Company
      issued and outstanding and entitled to vote as of the close of business on
      June 22, 1998, the record date established by the Board of Directors for
      the Annual Meeting. At the Annual Meeting, holders of a total of
      13,498,572 shares of Common Stock or approximately 74% of all stockholders
      entitled to vote were present in person or represented by proxy. The
      following sets forth the information regarding the results of the voting
      at the Annual Meeting:

Proposal 1. Election of Directors:

      Directors                      Shares Voting       Shares Voting
                                       In Favor             Against
                                     -------------       -------------
      Robert J. Hennessey*            13,420,397             78,175
      Alexander Rich, M.D.*           13,368,096            130,476
      Paul Schimmel, Ph.D.*           13,374,176            124,396
      Walter C. Herlihy, Ph.D.*       13,389,222            109,350
      G. William Miller*              13,351,921            146,651

* Incumbent

Proposal 2. Ratification of Selection of Arthur Andersen LLP as independent
            auditors:

      Shares voting in favor:         13,432,122
      Shares voting against:              34,335
      Abstention:                         32,115

Item 6.  EXHIBITS AND REPORTS ON FORM 8-K

(a) Exhibits

               EXHIBIT                               DESCRIPTION
               -------                               -----------

                 27.1                           Financial Data Schedule

(b) Reports on Form 8-K
      No current reports on Form 8-K were filed by the Company during the
      quarter covered by this report.


                                       11


                                    SIGNATURE

      Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned, thereunto duly authorized.


                                                  REPLIGEN CORPORATION
                                                  (Registrant)


Date: November 13, 1998                           By: /s/ Walter C. Herlihy
                                                      --------------------------
                                                      Chief Executive Officer

                                                      Principal Financial and
                                                      Accounting Officer


                                       12


                      REPLIGEN CORPORATION AND SUBSIDIARIES
                                  EXHIBIT INDEX

EXHIBIT NO.                       DESCRIPTION                         PAGE
- -----------                       -----------                         ----

27.1                         Financial Data Schedule                  14


                                       13