New HIV drug on the block

By Dr. Ananya Mandal, MDJul 22 2010

Johnson and Johnson’s experimental HIV drug rilpivirine or TMC278, a non-nucleoside reverse transcriptase inhibitor (NNRTI), is being developed for use in combination therapy for treating the human immunodeficiency virus (HIV) that causes AIDS. Two clinical trials with the drug has shown that although its effectiveness was same as the existing anti-HIV drugs, its side effects were fewer. On the flip side nearly twice as many patients failed to respond to treatment with the new drug.

Clinical evidence

According to the trial results from ECHO and THRIVE studies, 84.3 percent of HIV patients treated with TMC278 and Truvada (tenofovir and emtricitabine) achieved undetectable levels of the virus compared to 82.3 percent of patients treated with Atripla (Combination of tenofovir and emtricitabine and efavirenz) or similar drugs after 12 months of treatment. Drop outs were 2% among patients on TMC278 compared to 7.2 percent of the Sustiva (efavirenz) group. The results were revealed at the International AIDS Conference in Vienna on Thursday. As for serious side effects, 16 percent of TMC278 group and 31 percent of the Sustiva group suffered from side effects including psychiatric and neurologic problems. But the data also showed 9 percent of TMC278 patients experienced virologic failure compared to 4.8 percent of Sustiva-treated patients. This virological failure is concerning for experts since it could mean that the virus was mutating, making it resistant to other drugs in the same class.

Market

J&J has signed a deal with U.S. biotech company Gilead Sciences to develop a fixed dose combination of Gilead's Truvada and rilpivirine. At present Gilead has a once-daily pill, Atripla, that combines Truvada with Sustiva (A Bristol-Myers Squibb drug containing efavirenz). The combination is not making profits and loses its patent protection in the next few years. Under the deal with J&J, Gilead would keep up to 30 percent of TMC278 sales. In addition to the potential TMC278/Truvada combination, Gilead is developing a “Quad” pill that includes a component drug belonging to a new class of medicines called integrase inhibitors, designed to block genetic information needed for HIV to reproduce. At present an integrase inhibitor called Insentress has been developed by Merck & Co and it sold $752 million last year. GlaxoSmithKline has another of these in line.