Alnylam's RSV drug candidate misses primary endpoint in Ph IIb

Leading USA-based RNAi therapeutics firm Alnylam Pharmaceuticals (Nasdaq: ALNY) yesterday announced disappointing top-line results from a Phase IIb trial with ALN-RSV01 for the treatment of respiratory syncytial virus (RSV) infection in lung transplant patients.

The study missed the primary endpoint of reduced new or progressive bronchiolitis obliterans (BOS) in an “intent-to-treat” (ITTc) analysis of confirmed RSV infected patients (p=0.058), but achieved statistically significant reductions in prospectively defined analyses of ITTc patients with their “last observation carried forward” (LOCF) with a p-value of 0.028, and of ITTc patients treated “per protocol” (PP) with a p-value of 0.025. In all analyses, ALN-RSV01 treatment was associated with a clinically meaningful treatment effect, with a reduction of over 50% in the incidence of day 180 BOS as compared with placebo.

Will discuss next steps with US and European regulators