Positive interim analysis from ENVISION study of givosiran to treat acute hepatic porphyria.- Alnylam Pharma

Alnylam Pharmaceuticals, Inc. has announced positive topline results from the interim analysis of the ENVISION Phase III Study of givosiran, an investigational RNAi therapeutic targeting aminolevulinic acid synthase 1 (ALAS1) for the treatment of acute hepatic porphyria (AHP). The pre-specified interim analysis was based on lowering of urinary ALA levels as a surrogate biomarker that is reasonably likely to predict clinical benefit.

Results of the interim analysis showed that givosiran treatment was associated with a statistically significant reduction in urinary ALA levels in acute intermittent porphyria (AIP) patients, relative to placebo (p less than 0.001). The Company plans to discuss these data and the regulatory path forward with the FDA, and, pending the outcome of those discussions, intends to file a New Drug Application (NDA) at or around year-end 2018 in support of a potential Accelerated Approval.

The interim analysis had a data cut-off date of August 22, 2018 and included 43 patients with AHPs (41 patients with AIP, one with variegate porphyria [VP], and one with hereditary coproporphyria [HCP]) who were on study for at least three months. As of the data cut-off date, there were no deaths, and serious adverse events (SAEs) were reported in 22 percent (5/23) of givosiran patients and 10 percent (2/20) of placebo patients. One patient (4 percent) on givosiran discontinued treatment due to an increase in liver transaminase � which resolved � that was greater than eight times the upper limit of normal (ULN), a protocol-defined stopping rule. There were no treatment discontinuations in the placebo group.

Alnylam continues to dose patients in the ongoing ENVISION study, where enrollment was completed ahead of schedule with 94 AHP patients. The Company expects to report topline full study results of the primary endpoint � the annualized attack rate after six months of treatment � in early 2019.