Triple Therapies For HIV Provide Encouraging Data

Merck & Co and Abbott Laboratories have presented promising data for antiretroviral therapy based on existing reverse transcriptase inhibitors and their new protease inhibitors Crixivan (indinavir sulfate) and Norvir (ritonavir). The results were reported at the Third Conference on Retroviruses and Opportunistic Infections in Washington DC, USA, last week.

The new data was very well-received, sparking share price gains for Merck and Abbott as well as other firms involved in AIDS treatment, such as Glaxo Wellcome, even though the data comes from a preliminary analysis of two small studies. However, it comes at a time of considerable optimism in the AIDS arena with the first launch of a protease inhibitor, Hoffmann-La Roche's Invirase (saquinavir) at the end of 1995, and good combination therapy data from using GW's Retrovir (zidovudine) in combination with its new Epivir (lamivudine) drug (Marketletters December 18 & 25 and July 10).

NDA Filed For Crixivan Immediately after the presentation, Merck filed for approval of Crixivan in the USA. The dossier should be reviewed by the FDA's Antiviral Drugs Advisory Committee on March 1. At a satellite symposium held at the beginning of the conference, Emilio Emini, executive director of antiviral research at Merck Research Laboratories, described preliminary data from two new clinical studies of Crixivan 800mg/day as part of triple therapy for HIV. The first three-arm trial compared Crixivan alone, zidovudine plus lamivudine and the combination of all three drugs in HIV-positive patients who had previously been treated with zidovudine.