<PAGE>
Exhibit 99.1
DRAFT RELEASE
VERTEX PHARMACEUTICALS ANNOUNCES ITS INTENTION TO REDEEM ITS 5% CONVERTIBLE
SUBORDINATED NOTES DUE 2007
CAMBRIDGE, MA, SEPTEMBER 8, 2000 -- Vertex Pharmaceuticals Incorporated (Nasdaq:
VRTX) today announced that it expects to mail on or after September 15, 2000 a
notice to call for redemption in October 2000 its $175 million aggregate
principal amount of 5% Convertible Subordinated Notes due 2007. Prior to the
redemption date, holders may convert their Notes into Vertex Common Stock. Based
on the current market price of its Common Stock, Vertex expects that holders of
the Notes will choose to convert their Notes into Common Stock rather than
accept redemption.
Upon redemption, Vertex will pay holders of the Notes $1,000 per $1,000
principal amount of Notes, plus accrued interest. In addition, Vertex will pay a
"make-whole" payment of $82.14 per $1,000 principal amount of Notes
(approximately $14.4 million in total) to all holders of the Notes on the notice
date, including holders who convert their Notes prior to the redemption date.
The "make-whole" payment will result in Vertex recognizing a one-time charge of
approximately $14.4 million in the third quarter of this year. Holders are
entitled to convert the Notes into shares at a conversion price of $40.32 per
share, or approximately 24.8 shares of Common Stock per $1,000 principal amount
of Notes, after adjustment for the two-for-one stock split of Vertex Common
Stock paid in the form of a stock dividend on August 23, 2000.
If all of the Notes are converted, Vertex will issue approximately 4.3 million
shares of Common Stock, increasing the Company's total shares outstanding to
approximately 58.4 million shares. If none of the Notes are converted, Vertex
will make an aggregate redemption payment of $175 million, plus accrued
interest, in addition to the $14.4 million total "make-whole" payment.
Vertex Pharmaceuticals Incorporated discovers, develops and markets small
molecule drugs that address major unmet medical needs. Vertex has eight drug
candidates in clinical development to treat viral diseases, inflammation,
cancer, autoimmune diseases and neurological disorders. Vertex has created its
pipeline using a proprietary, information-based approach to drug design that
integrates multiple technologies in biology, chemistry and biophysics, aimed at
increasing the speed and success rate of drug discovery. Vertex's first approved
product is Agenerase(TM) (amprenavir), an HIV protease inhibitor, which Vertex
co-promotes with Glaxo Wellcome.
Page 5 of 8 pages
<PAGE>
Vertex Pharmaceuticals Incorporated
Vertex Announces its Intention to Redeem its 5% Convertible Subordinated Notes
Due 2007
September 8, 2000
Page 2
The foregoing information regarding Vertex's intention to call for redemption
and the expected conversion of its Convertible Subordinated Notes is forward
looking. While management makes its best efforts to be accurate in making
forward-looking statements, any such statements are subject to risks and
uncertainties that could cause actual results to vary materially. Risk factors
include the possibility that Vertex's Common Stock price could decrease
substantially, affecting the Company's decision to call the Notes for redemption
or the decisions of investors whether to convert the Notes prior to redemption.
Investors are directed to consider other risks and uncertainties discussed in
Vertex documents filed with the Securities and Exchange Commission.
This press release is not Vertex's notice of redemption under the indenture
governing the Notes. Vertex is not obligated to redeem the Notes or make the
"make-whole" payment to any holder until the notice of redemption is mailed to
holders of the Notes in accordance with the indenture.
Vertex's press releases are available at WWW.VPHARM.COM, or by fax-on-demand at
(800) 758-5804 -- Code: 938395.
# # #
VERTEX CONTACTS:
Lynne H. Brum, Vice President, Corporate Communications, (617) 577-6614 or
Michael Partridge, Associate Director, Corporate Communications (617) 577-6108
or Katie Burns, Manager, Investor Relations, (617) 577-6656
Page 6 of 8 pages
