New data were presented from a GlaxoSmithKline (GSK)-sponsored study (APV30005) that evaluated the long-term efficacy and tolerability of Telzir (fosamprenavir), a new protease inhibitor, in treatment-naive HIV infected adults. The preliminary data showed sustained HIV suppression and improved immunological status over 96 weeks in patients receiving Telzir with ritonavir (RTV) once-daily in combination with other anti-HIV drugs, according to a GSK release.

The presentation was made at the XV International AIDS Conference (IAC) in Bangkok, Thailand. "We are encouraged by the interim analyses of 96-week data that suggest the potency and safety demonstrated by Telzir/RTV at 48 weeks (SOLO2 study) may be sustained long-term in treatment-naïve
HIV patients," said Doug Manion, vice president of HIV clinical development and medical affairs at GSK.

APV30005 is a follow-up study partially comprised of patients previously enrolled in SOLO, a 48-week phase III clinical trial. A total of 210 patients who completed SOLO and achieved and maintained undetectable viral load levels through at least 48 weeks of treatment subsequently enrolled in the follow up study. These patients continued to receive Telzir dosed with RTV once a day in combination with abacavir and lamivudine. Of these patients, 115 have so far completed 96 weeks of therapy before the deadline for data collection and were included in the interim analysis presented today at IAC.

Of 113 patients for whom lab data were available at 96 weeks, 96 per cent (n=109) had undetectable levels of HIV (as measured by plasma HIV-1 RNA <400 copies per ml of blood), and 86 per cent (n=97) had a viral load below 50 copies/ml of blood at 96 weeks. At 96 weeks, patients experienced a median increase in CD4+ cells of 263 cells/mm3 indicating continued immunological improvement. No selection for protease resistant mutations was observed in any patients with virological failure who completed the 96 weeks of follow-up.

The treatment regimen was well-tolerated, and no new safety concerns were identified over the time period in the study. Diarrhoea (9%) and nausea (7%) were the most common grade 2-4 drug-related adverse events reported over the full study period. In APV30005, only four additional patients discontinued the study due to an adverse event.

In summary, these data demonstrate that long-term treatment with Telzir/RTV resulted in sustained virological suppression, continued immunological improvement, and no selection of protease inhibitor resistance over 96 weeks in this interim analysis. Telzir/RTV was well- tolerated with few discontinuations due to adverse events.

In treatment-naive patients, Telzir/RTV has been studied in clinical trials as once daily with RTV or twice daily with or without RTV. All of the regimens studied have a low pill burden (4 tablets/day) without dietary or water restrictions, which may support long-term adherence to therapy in HIV-infected patients. Telzir was co-discovered by GSK and Vertex Pharmaceuticals.