Merck integrase inhibitor making progress too
Merck & Co presented results of a phase II study of an integrase inhibitor called MK-0518 at the European AIDS Clinical Society conference in Dublin last October.
In the double-blin study 35 treatment-naive individuals were given one of four doses of MK-0518 as monotherapy (100 mg, 200 mg, 400 mg, 600 mg) or placebo twice daily for 10 days. Patients at baseline had HIV-RNA of at least 5,000 copies/mL and CD4 counts of at least 100 cells/mm
Results demonstrated a 1.7 to 2.2 log copies/ml reduction in HIV-RNA across all MK-0518 treatment groups (a decline of 98 percent from baseline) and a 0.2 log copies/mL reduction for placebo (p
MK-0518 therapy was generally well tolerated. The most common adverse experiences (AEs) were headache, fatigue and dizziness; these were similar between the MK-0518 and the placebo groups. There were no discontinuations due to AEs and no serious AEs1.
Based on these results, a 48-week dose-ranging trial of MK-0518 versus efavirenz - a non-nucleoside reverse transcriptase inhibitor - in combination therapy has begun in treatment-naïve patients.
A potential anti-HIV integrase inhibitor is to be explored further in clinical trials, the drugs company Gilead Sciences has announced.
Encouraging results from a phase I/II clinical study to find the most effective dose of the integrase inhibitor, which has the laboratory name GS 9137 (formerly JTK-303), has led Gilead to design larger phase II and phase III clinical trials. Gilead plans to present the results from the dose escalation study at a scientific conference later this year.
In the first half of 2006, the safety and efficacy of three once-daily doses of GS 9137 (20mg, 50mg and 125mg) boosted by 100mg of the protease inhibitor ritonavir will be examined in the phase II study.
“We are encouraged by the significant viral load reduction observed in HIV-infected patients in the phase I/II study in which the 50mg dose, in combination with ritonavir as a boosting agent, showed antiviral activity similar to the most potent protease inhibitors,” said Norbert Bischofberger of Gilead, “we are working quickly to finalise the protocol design so we may initiate larger phase II and phase III studies.”
Gilead acquired exclusive development and commercialisation rights for GS 9137 in all countries except Japan from Japan Tobacco in 2005.
More information
For more information on integrase inhibitors click here.
For a factsheet explaining the stages of clinical trials, click here.