First Amendment To Stockholders Rights Agreement

Exhibit A


FIRST AMENDMENT
TO
TRIANGLE PHARMACEUTICALS, INC.
STOCKHOLDER RIGHTS AGREEMENT


This First Amendment (the "AMENDMENT") to the Triangle Pharmaceuticals, Inc. Stockholder Rights Agreement (the "AGREEMENT") dated as of June 2, 1999, by and between Triangle Pharmaceuticals, Inc., a Delaware corporation (the "COMPANY"), and Abbott Laboratories, an Illinois corporation ("PURCHASER"), is made and entered into as of the 30th day of July, 2002. Capitalized terms used herein that are not otherwise defined herein shall have the meanings given them in the Agreement.


RECITALS


WHEREAS, in connection with Purchaser's acquisition of certain shares of Common Stock of the Company in June 1999, the Company and Purchaser entered into the Agreement to provide Purchaser with certain rights related to the Common Stock issued to Purchaser and certain other matters, as described therein;


WHEREAS, the Company and Purchaser now desire to amend and supplement the Agreement in the manner set forth below;


WHEREAS, Section 8.1 of the Agreement provides that the Agreement may be amended by a written agreement of the Company and Purchaser;


NOW, THEREFORE, in consideration of the above and the mutual covenants described below, the Company and Purchaser hereby agree to amend the Agreement as follows:


1. Section 1.2 "COMPANY REGISTRATION" is hereby deleted and replaced in its entirety as follows:


Section 1.2 REGISTRABLE SECURITIES. "Registrable Securities" include
such portion of the Shares which have not previously been registered or
otherwise sold to the public.


2. Section 1.3 "UNDERWRITING" shall be deleted in its entirety.


3. Section 3.3 "RIGHT OF FIRST REFUSAL" is hereby deleted and replaced in its entirety as follows:


3.3 RIGHT OF FIRST REFUSAL.


In the event Purchaser desires to transfer any or all of its
Restricted Securities (i) in a private transaction or block sale to a buyer
who is engaged in business in the pharmaceutical or biotechnology
industries or, to the knowledge of Purchaser, is acting in concert with or
on behalf of another party who is engaged in business in either of those


industries, (ii) to a buyer who, to the knowledge of Purchaser after
reasonable inquiry, has filed publicly any notice or form with the SEC of
its intent to hold or acquire the Company's securities with the purpose of
changing or influencing control of the Company, which shall include seeking
representation on the Company's Board of Directors, or (iii) in a block
trade to a "qualified institutional buyer," as that term is defined in Rule
144A promulgated under the Securities Act ("QIB"), who is not a buyer under
(i) or (ii) and which block trade, when combined with the number of the
Company's securities sold or otherwise transferred by Purchaser within the
preceding ninety (90) days, exceeds 2.5% of the Company's then outstanding
Common Stock, Purchaser must deliver a notice in writing to the Company
("Notice") by overnight mail stating (A) its bona fide intention to sell or
transfer such securities, (B) the total number of such Restricted
Securities to be sold or transferred (including Restricted Securities
within the Section 5.1 volume limitations that constitute part of the
proposed sale or transfer), (C) the price, if any, for which Purchaser
proposes to sell or transfer such Restricted Securities, and (D) the name
of the proposed purchaser or transferee (except for a Notice provided in
connection with (iii) above, in which case no proposed buyer need be
identified). In the event the proposed transfer is partially or completely
in exchange for assets other than cash, then such assets shall be deemed to
have a cash value in the amount determined by the Company's Board of
Directors in its sole good faith opinion, in which case such cash value
ascertained by the Board, when added to any cash to be exchanged and then
divided by the number of Restricted Securities to be transferred, shall be
deemed the price per security set forth in the Notice.


The Company shall then have an exclusive, irrevocable option (the
"Company Option"), at any time within ten (10) business days of receipt of
the Notice, to purchase some or all of the Restricted Securities to which
the Notice refers at the price per security specified in the Notice (as
determined above). The Company shall exercise the Company Option by written
notice signed by an officer of the Company and delivered or mailed to the
Purchaser (the "Company Settlement Notice"), which notice shall specify the
time, place and date for settlement of such purchase, such date to be not
more than three (3) business days after the date of the Company Settlement
Notice.


On or before the third business day after the date of the Company
Settlement Notice, the Purchaser must deliver to the Company all
certificates or other related documentation for the securities being
acquired by the Company which are not already in the Company's custody,
together with proper assignments in blank of the Restricted Securities with
signatures properly guaranteed and with such other documents as may be
required by the Company to provide reasonable assurance that each necessary
endors ...