AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON MAY 9, 2002 REGISTRATION NO. 333-81745 ================================================================================ SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 --------------------------------- POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-3 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 ---------- TRIANGLE PHARMACEUTICALS, INC. (Exact name of Registrant as Specified in Its Charter) Delaware 56-1930728 (State or Other Jurisdiction of (I.R.S. Employer Incorporation or Organization) Identification No.) ---------- 4 University Place, 4611 University Drive, Durham, North Carolina, 27707 (919) 493-5980 (Address, Including Zip Code, and Telephone Number, Including Area Code, of Registrant's Principal Executive Offices) ---------- Chris A. Rallis President and Chief Operating Officer TRIANGLE PHARMACEUTICALS, INC. 4 University Place, 4611 University Drive, Durham, North Carolina 27707 (919) 493-5980 (Name, Address, Including Zip Code, and Telephone Number, Including Area Code, of Agent for Service) ---------- COPY TO: Rachel Mandell, Esq. Senior Corporate Counsel TRIANGLE PHARMACEUTICALS, INC. 4 University Place 4611 University Drive Durham, North Carolina 27707 (919) 493-5980 ---------- DEREGISTRATION OF SHARES Triangle Pharmaceuticals is filing this post effective amendment to deregister, as of the date hereof, 1,700,000 shares of Triangle Pharmaceuticals' common stock remaining unsold at the conclusion of the offering described in the registration statement on Form S-3 (Reg. No. 333-81745). The shares were being offered by selling stockholders of Triangle Pharmaceuticals. SIGNATURES Pursuant to the requirements of the Securities Act, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-3 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Durham, State of North Carolina, on the 9th day of May, 2002. TRIANGLE PHARMACEUTICALS, INC. By: /s/ Chris A. Rallis --------------------------------------- Chris A. Rallis President and Chief Operating Officer Pursuant to the requirements of the Securities Act, this Registration Statement has been signed by the following persons in the capacities and on the dates indicated: Signature Title --------- ----- /s/ Chris A. Rallis Director, President and Chief Operating Officer May 9, 2002 --------------------------------------- (Principal Executive Officer) Chris A. Rallis /s/ Robert F. Amundsen, Jr. Executive Vice President and Chief Financial May 9, 2002 --------------------------------------- Officer (Principal Financial and Accounting Robert F. Amundsen, Jr. Officer) /s/ Anthony B. Evnin Director May 9, 2002 --------------------------------------- Anthony B. Evnin /s/ Standish M. Fleming Director May 9, 2002 --------------------------------------- Standish M. Fleming /s/ Dennis B. Gillings Director May 9, 2002 --------------------------------------- Dennis B. Gillings /s/ Henry G. Grabowski Director May 9, 2002 --------------------------------------- Henry G. Grabowski /s/ Stewart J. Hen Director May 9, 2002 --------------------------------------- Stewart J. Hen /s/ Jonathan S. Leff Director May 9, 2002 --------------------------------------- Jonathan S. Leff /s/ George McFadden Director May 9, 2002 --------------------------------------- George McFadden /s/ James L. Tyree Director May 9, 2002 --------------------------------------- James L. Tyree