Ian McGowan, from Gilead Sciences, reported data from study 902 in which PMPA (administered once daily) was simply added onto ongoing therapy for individuals. This data was previously reported at ICAAC in September. More details of this study are available on NATAP web site in ICAAC Highlights Reports.

He reported data first from study 901 which was a 4-week, placebo controlled, dose ranging study in treatment na´ve and experienced patients.

Three doses were given: 75 mg, 150 mg, and 300 mg, all once daily. For the experienced group receiving the highest dose of 300 mg there was a ľ1.06 log reduction, while the treatment-na´ve group experienced a ľ1.51 log reduction.

Three PMPA once daily doses were given in study 902: 75, 150, or 300 mg. The median time on study is now 37 weeks with a range of 32-60 weeks.  The patients had about 4.5 years of prior treatment experience. The mean baseline CD4 and viral load in the 300 mg dose arm (n=55) was 378 and 3.74 log (5,500 copies/ml). 91% were male.

Baseline NRTI Resistance (n=187). The study group was very treatment experienced. 6% of patients had no NRTI mutations at baseline. About 60% of patients had PI mutations. 35% had NNRTI mutations. 43% had high AZT resistance with 3TC resistance (M184V). 24% had high AZT resistance. 19% had low AZT resistance with the M184V (3TC) mutation.

Viral Load Response.  There was a dose dependent response with a mean of 0.75 log drop in 300 mg group at week 24. Over the course of the study they did not see a significant CD4 rise in any arms.

Nephrotoxicity.  The incidence of serious adverse events: 3/28 (11%) in placebo arm, 5/53 (9%) in 75 mg arm, 8/51 (16%) in 150 mg arm, 3/54 (6%) in 300 mg arm. Grade 1 creatinine toxicity is a rise above 0.5 mg/dL So far they have not observed any rises above 0.5 mg in serum creatinine in the 300 mg group except for a few fluctuations.