Gammagard Liquid 10%: Phase III data

Top-line data from the double-blind, North American Phase III GAP trial (Study 160701) in 390 patients with mild to moderate AD showed that both 200 and 400 mg/kg doses of IV Gammagard given every 2 weeks missed the co-primary endpoints of reducing functional decline as measured by ADAS-Cog scores and of preserving functional abilities as measured ADAS-ADL scores from baseline to 18 months vs. placebo. Specifically, mean ADAS-Cog scores increased from baseline to 18 months by 8.9 points in the low-dose Gammagard arm and by 7.4 points in the high-dose Gammagard arm vs. 8.4 points in the placebo arm (p>0.1 for both). For the ADAS-Cog endpoint, higher scores indicate greater impairment. Mean ADCS-ADL scores decreased from baseline to 18 months by 12.4 points in the low-dose Gammagard arm and by 11.4 points in the high-dose Gammagard arm vs. 11.4 points in the placebo arm (p>0.1 for both). For the ADAS-ADL endpoint, lower scores indicate greater impairment. Low- and high-dose Gammagard also missed the secondary endpoint of improving 3MS scores from baseline to 18 months vs. placebo. Specifically, mean 3MS scores decreased from baseline to 18 months by 15.3 points in the low-dose Gammagard arm and by 12.1 points in the high-dose Gammagard arm vs. 13.5 points in the placebo arm (p>0.1 for both). For the 3MS endpoint, lower scores indicate greater impairment.

Although pre-specified subgroup analyses were not powered for significance, Baxter said that high-dose Gammagard showed a positive numerical difference in ADAS-Cog and 3MS scores vs. placebo. In patients with moderate AD, mean ADAS-Cog scores increased by 9.6 points in the high-dose Gammagard arm vs. 12.9 points in the placebo arm (p=0.083) and mean 3MS scores decreased by 14 points in the high-dose Gammagard arm vs. 18.1 points in the placebo arm (p=0.067). In patients with mild to moderate AD who were carriers of the apolipoprotein E epsilon 4 (APOE4) genotype, mean ADAS-Cog scores increased by 7.4 points in the high-dose Gammagard arm vs. 8.8 points in the placebo arm (p>0.1) and mean 3MS scores decreased by 10.6 points in the high-dose Gammagard arm vs. 14.9 points in the placebo arm (p=0.012). Gammagard was well tolerated. Additional data will be presented at the Alzheimer's Association International meeting in Boston in July. ...