Exhibit 11.1 Triangle Pharmaceuticals, Inc. (A Development Stage Company) Computation of Net Loss Per Common Share (In thousands, except per share amounts) Three Months Six Months Three Months Six Months Ended Ended Ended Ended June 30, 1998 June 30, 1998 June 30, 1997 (1) June 30, 1997 (1) ------------- ------------- ----------------- ----------------- Historical weighted average shares outstanding ....... 23,425 21,725 18,135 17,859 ---------------- ---------------- ---------------- ---------------- Shares used in computing net loss per common share .... 23,425 21,725 18,135 17,859 ================ ================ ================ ================ Net Loss ................... $ (14,256) $ (30,664) $ (5,617) $ (9,161) ================ ================ ================ ================ Basic and diluted net loss per common share ......... $ (0.61) $ (1.41) $ (0.31) $ (0.51) ================ ================ ================ ================ - ---------- (1) The weighted average shares outstanding used in the calculation of net loss per common share have been restated to reflect the adoption of Statement of Financial Accounting Standards No. 128, "Earnings Per Share" and its interpretation by Securities and Exchange Staff Accounting Bulletin No. 98.