NEW HAVEN, Conn., Jan. 31, 2008 (PRIME NEWSWIRE) -- Achillion Pharmaceuticals, Inc. (Nasdaq:ACHN), a leader in the discovery and development of small molecule drugs to combat the most challenging infectious diseases, today announced positive safety and efficacy results from two ongoing Phase 2 clinical trials studying elvucitabine in patients infected with Human Immunodeficiency Virus (HIV). Elvucitabine, Achillion’s HIV product candidate, is an L-cytosine nucleoside analog reverse transcriptase inhibitor (NRTI) that has previously demonstrated potent antiviral activity against HIV, including strains resistant to other NRTIs.