Chennai Patent Office has lately issued an Indian Patent No. 212400 for antiretroviral drug Raltegravir against the mail-box application no. 868/CHENP/2004 claiming priority from US provisional application dated October 26, 2001. Last year in October, Merck’s received the market approval for Raltegravir by the US Food & Drug Administration. Globally marketed as Isentress, Raltegravir (earlier known as MK-0518) belongs to a new class of HIV drugs, integrase inhibitors, and is invented by Italian scientists working at Istituto di Ricerche di Biologia Molecolare P. Angeletti (IRBM), Rome-based drug discovery research center for human viral diseases and cancers.