<Page> ---------------------------- OMB APPROVAL ---------------------------- OMB Number: 3235-0060 Expires: May 31, 2000 Estimated average burden hours per response.....5.00 ---------------------------- UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported) November 30, 2001 ------------------------------ TRIANGLE PHARMACEUTICALS, INC. - -------------------------------------------------------------------------------- (Exact name of registrant as specified in its charter) DELAWARE 000-21589 56-1930728 - ----------------------------- --------------------------- ---------------------- (State or other jurisdiction (Commission (IRS Employer of incorporation) File Number) Identification No.) 4 University Place, 4611 University Drive, Durham, North Carolina 27707 - -------------------------------------------------------------------------------- (Address of principal executive offices) (Zip Code) Registrant's telephone number, including area code (919) 493-5980 ----------------------------- - -------------------------------------------------------------------------------- (Former name or former address, if changed since last report) <Page> Item 5. Other Events. On November 30, 2001, Triangle Pharmaceuticals entered into a Master Loan and Security Agreement with Wells Fargo Equipment Finance, Inc., a copy of which is attached hereto as Exhibit 10.1. and is incorporated herein by reference Item 7. Financial Statements, Pro Forma Financial Information and Exhibits. (c) Exhibits. The following documents are filed as exhibits to this Report: 10.1 Master Loan and Security Agreement dated November 30, 2001 between Triangle Pharmaceuticals, Inc. and Wells Fargo Equipment Finance, Inc. SIGNATURES Pursuant to the requirements of the Securities Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized. Triangle Pharmaceuticals, Inc. --------------------------------------------- (Registrant) December 7, 2001 /s/ Robert F. Amundsen, Jr. - ------------------------------- --------------------------------------------- Date (Signature) Name: Robert F. Amundsen, Jr. Title: Executive Vice President & Chief Financial Officer