EXHIBIT 99.1
                              FOR IMMEDIATE RELEASE

Contact: Michael Gury                                       Jodi Amendola
         IMS HEALTH Communications                     TriZetto Communications
         (203) 222-4230                                   (480) 657-9966

         Jack Walsh                                       Ethan Denkensohn
         IMS HEALTH Investor Relations Relations          TriZetto Investor
         (203) 222-4250                                    (212) 213-0006

IMS HEALTH AND TRIZETTO TERMINATE MERGER AGREEMENT NEW STRATEGIC ALLIANCE
INCLUDES TRIZETTO'S ACQUISITION OF ERISCO; PLUS HEALTHWEB AND DATA AGREEMENT
WITH IMS HEALTH

WESTPORT, CT and NEWPORT BEACH, CA, May 16, 2000 -- IMS HEALTH (NYSE:RX) and The
TriZetto(R) Group, Inc. (Nasdaq:TZIX) today jointly announced a strategic
alliance under which TriZetto will acquire Erisco Managed Care Technologies, a
subsidiary of IMS HEALTH, for TriZetto stock. Further, IMS HEALTH and TriZetto
will enter a technology and data partnership. The alliance supersedes the merger
of the two companies announced March 29,2000, which has been terminated by the
consent of both Boards of Directors.

      TriZetto is a leading provider of vertical, Internet-enabled application
services and business portals to the healthcare industry. IMS HEALTH is the
world's leading provider of information solutions to the pharmaceutical and
healthcare industries. The new agreement calls for issuance of TriZetto stock in
exchange for Erisco, a leading provider of technology solutions supporting 70
million managed care lives worldwide. Based on TriZetto's closing price on May
16, 2000, of $24.00, IMS HEALTH would receive approximately 10.63 million
TriZetto shares, representing 30.1% on a fully diluted pro forma basis, valuing
Erisco at $255 million. The transaction is structured with a customary collar
between a $21 TriZetto stock price, below which IMS HEALTH receives 12.1 million
TriZetto shares, and a $29 TriZetto stock price, above which IMS HEALTH receives
8.8 million shares. The final exchange ratio will be determined by TriZetto's
average daily price for the 15 trading days ending on the third day prior to the
closing date, which is expected in August/September 2000.

      IMS HEALTH and TriZetto will remain separate, independently traded public
companies.

      As part of the Erisco transaction, TriZetto's Board of Directors will
include an IMS HEALTH representative. IMS HEALTH has also committed to enter a
business contract for TriZetto's HealthWeb(SM) product and technology services.
The HealthWeb Internet portal, augmented with TriZetto's ASP technology, will
facilitate an acceleration





of IMS HEALTH's Internet strategy. Access to new information sources will enable
the development of future IMS HEALTH products.

      "This new approach retains the strategic benefits of the original
transaction in a simpler form designed to be more attractive to shareholders,"
said Victoria R. Fash, president and CEO of IMS HEALTH. "We are committed to the
IMS HEALTH business strategy, facilitated by our new partnership with TriZetto."

      "We are very pleased to have developed a strong strategic relationship
with IMS HEALTH while accelerating the ASP model which has successfully driven
our industry leading position," said Jeffrey H. Margolis, TriZetto chairman and
CEO. "Erisco extends TriZetto's ability to provide the widest selection of
applications to our customers on a pre-integrated basis. TriZetto will maintain
its vendor neutral approach to the market, generating revenue from Erisco
through licensing and offering Erisco Facets(TM) and Facts on an ASP basis,
together with our other best-of-class 3rd party offerings. Erisco's strong
positive cash flow will fuel the growth of our ASP business."

      Separately, IMS HEALTH reaffirmed its intent to spin-off Strategic
Technologies, a unit of IMS HEALTH. Strategic Technologies, the global market
leader in customized Pharmaceutical Relationship Management (PRM) solutions,
helps pharmaceutical companies achieve maximum return on their sales and
marketing investments. The Strategic Technologies spin-off will be structured as
a tax-free distribution to shareholders, anticipated to be complete in July
2000.

      "We are re-affirming the IMS HEALTH year 2000 growth rate guidance of 15
percent constant dollar revenue growth, and 20 percent EPS growth, on a
post-transaction basis," said James Malone, chief financial officer of IMS
HEALTH.

      The TriZetto acquisition of Erisco is subject to SEC regulatory clearance,
Hart-Scott Rodino approval and approval of TriZetto shareholders.

      For a copy of investor kits related to this announcement, click here.
< http://www.imshealth.com/html/iik/tzixrx.htm >

      The TriZetto Group, Inc. is a leading provider of vertical,
Internet-enabled application services and business portals for the healthcare
industry. As an application services provider, TriZetto hosts software for a
predictable monthly fee, saving customers significant time, money and
frustration. HealthWeb, its Internet portal, assists healthcare administrators
and professionals in performing their routine tasks and facilitates
information-exchange and e-commerce among all key healthcare participants:
providers, health plans and employers and health-plan members. Additional
information is available at http://www.trizetto.com.

      IMS HEALTH is the world's leading provider of information solutions to the





pharmaceutical and healthcare industries. With $1.4 billion in 1999 revenue, IMS
HEALTH operates in over 100 countries. IMS HEALTH is the largest pharmaceutical
manufacturer information partner, with over 40 years experience in the industry.
Key products and services integral to customer day-to-day operations include:
market research for prescription and over-the-counter pharmaceutical products;
sales management information to optimize sales force productivity;
pharmaceutical relationship management solutions for sales and marketing
decision-making; and technology systems and information services that support
managed care organizations. Additional information is available at
http://www.imshealth.com.

      # # # This press release may contain forward-looking information
(statements that are not historical facts and relate to future performance) that
involves risks and uncertainties. The forward-looking statements are made
pursuant to the Safe Harbor provisions of the Private Securities Litigation
Reform Act of 1995. These forward-looking statements may include statements
about future net revenues, profits, and financial results, the market for
TriZetto's services, future service offerings, client and partner relationships,
and TriZetto's operational capabilities. Actual results may differ materially
from those stated in any forward-looking statements based on a number of
factors, including the effectiveness of TriZetto's implementation of its
business plan, the market's acceptance of TriZetto's services, risks associated
with management of growth, reliance on third parties to supply key components of
TriZetto's services, attraction and retention of employees, variability of
quarterly operating results, including the effects of the client purchasing
patterns due to Year 2000 issues, competitive factors, risks associated with
acquisitions, changes in demand for third party products or solutions, which
form the basis of TriZetto's service offerings, and risks associated with
rapidly changing technology, as well as the risks identified in TriZetto's SEC
filings.

      This press release includes statements which may constitute
forward-looking statements made pursuant to the safe harbor provisions of the
Private Securities Litigation Reform Act of 1995. Although IMS HEALTH believes
the expectations contained in such forward-looking statements are reasonable, it
can give no assurance that such expectations will prove correct. This
information may involve risks and uncertainties that could cause actual results
of IMS HEALTH to differ materially from the forward-looking statements. Factors
which could cause or contribute to such differences include, but are not limited
to (i) the risks associated with operating on a global basis, including
fluctuations in the value of foreign currencies relative to the U.S. dollar, and
the ability to successfully hedge such risks, (ii) to the extent IMS HEALTH
seeks growth through acquisitions and joint ventures, the ability to identify,
consummate and integrate acquisitions and ventures on satisfactory terms, (iii)
the ability to develop new or advanced technologies and systems for its
businesses on time and on a cost-effective basis, (iv) regulatory, legislative
and enforcement initiatives, particularly in the areas of medical privacy and
tax, and (v) deterioration in economic conditions, particularly in the
pharmaceutical, healthcare or other industries in which IMS HEALTH's customers
operate. Additional information on factors that may affect the business and
financial





results of the Company can be found in filings of the Company made from time to
time with the Securities and Exchange Commission.

      WE URGE INVESTORS AND SECURITY HOLDERS TO READ THE PROXY STATEMENT OF
TRIZETTO RELATING TO THE TRANSACTION DESCRIBED ABOVE, WHEN IT BECOMES AVAILABLE,
BECAUSE IT WILL CONTAIN IMPORTANT INFORMATION. WHEN THIS AND OTHER DOCUMENTS
RELATING TO THE TRANSACTION ARE FILED WITH THE U.S.
SECURITIES AND EXCHANGE COMMISSION, THEY MAY BE OBTAINED FREE AT THE SEC'S WEB
SITE AT www.sec.gov. YOU MAY ALSO OBTAIN EACH OF THESE DOCUMENTS (WHEN THEY
BECOME AVAILABLE) FOR FREE FROM TRIZETTO BY DIRECTING YOUR REQUEST TO THE
INVESTOR RELATIONS CONTACT PERSONS IDENTIFIED BELOW.

      ADDITIONAL INFORMATION AND WHERE TO FIND IT

      TriZetto plans to file with the Securities and Exchange Commission (the
"SEC") and to mail to stockholders of TriZetto a Proxy Statement containing
information about the transaction described above. Investors and security
holders are urged to read the Proxy Statement and other documents filed with the
SEC carefully when they are available. The Proxy Statement and other filings
will contain important information about TriZetto, Erisco, the acquisition, the
persons soliciting proxies relating to the acquisition, their interests in the
acquisition, and related matters. Investors and security holders will be able to
obtain free copies of these documents through the website maintained by the SEC
at http://www.sec.gov. Investors will be able to obtain copies of the documents
free of charge from TriZetto by calling Investor Relations, telephone: (480)
657-9966. In addition to the Proxy Statement, TriZetto files annual, quarterly
and special reports, proxy statements and other information with the SEC. You
may read and copy any reports, statements or other information filed by TriZetto
at the SEC public reference rooms at 450 Fifth Street, N.W., Washington, D.C.
20549 or at any of the SEC's other public reference rooms in New York, New York
and Chicago, Illinois. Please call the SEC at 1-800-SEC-0330 for further
information on the public reference rooms. TriZetto's filings with the SEC are
also available to the public from commercial document-retrieval services and at
the Web sit maintained by the SEC at http://www.sec.gov.

      INVESTORS SHOULD READ THE PROXY STATEMENT CAREFULLY WHEN IT BECOMES
AVAILABLE BEFORE MAKING ANY VOTING OR INVESTMENT DECISIONS. NOTHING HEREIN SHALL
CONSTITUTE AN OFFER OR ANY SECURITIES FOR SALE.

      TriZetto and its directors and executive officers, who may be considered
participants in this transaction, and certain other members of management and
employees may be soliciting proxies from TriZetto's stockholders in favor of
approval and adoption of the issuance of shares in connection with the merger
agreement. Information




concerning the participants in the solicitation will be set forth in the Proxy
Statement when it is filed with the SEC. In addition, information about
TriZetto's directors and executive officers is set forth in TriZetto's Annual
Report on Form 10-K for the year ended December 31, 1999, which is filed with
the SEC.