Safety worries mar good efficacy data for Alnylam's givosiran

Following mixed results in a clinical study, Alnylam Pharmaceuticals (Nasdaq: ALNY) lost ground in pre-market trading on Wednesday, ticking down nearly 3% in morning trading.

The RNAi therapeutics specialist announced that the ENVISION Phase III study of givosiran, an investigational treatment for acute hepatic porphyria (AHP), met its primary efficacy endpoint and the majority of secondary endpoints.

However, analysts Mani Foroohar and Rick Bienkowski of SVB Leerink warned in a research note that the safety profile was “materially worse than expected.”