Expanded access program for Merck & Co's MK-0518

A worldwide expanded access program for HIV/AIDS patients with limited or no treatment options has been announced by US drug major Merck & Co with respect to its investigational HIV integrase inhibitor MK-0518, now in Phase III development. Program enrollment will begin in the next few months, pending regulatory review and approvals.

"Making MK-0518 available to those who would like access to this investigational drug but who are unable to participate in the clinical studies underscores our commitment to patients," said Peter Kim, president of Merck Research Laboratories.

MK-0518 belongs to a new class of investigational antiretroviral therapy agents called integrase inhibitors that inhibit the insertion of the HIV viral DNA into human DNA. Integrase is one of three HIV enzymes - reverse transcriptase, protease and integrase - required by the virus to reproduce, explains Merck, adding that drugs are available that inhibit the functions of the protease and reverse transcriptase enzymes but, to date, there are no approved drugs that target the integration stage of the HIV-1 lifecycle.