Complete 18-Month Data from Ongoing Phase 2 OLE Study with Patisiran in Development for the Treatment of Hereditary TTR-Mediated Amyloidosis with Polyneuropathy (hATTR-PN)

We reported results from our ongoing Phase 2 open-label extension (OLE) study with patisiran at the 68th Annual Meeting of the American Academy of Neurology (AAN), held April 15 – 21, 2016 in Vancouver, British Columbia, Canada.  Complete 18-month data (N=27) from the study provided continued evidence that patisiran has the potential to halt neuropathy progression in patients with hATTR-PN (also known as familial amyloidotic polyneuropathy, or FAP), showing a mean 0.8-point decrease in mNIS+7, which compares favorably to an estimated increase in mNIS+7 of 22 to 26 points at 18 months based upon analysis of historical data sets in untreated hATTR-PN patients with similar baseline neurologic impairment. Patisiran administration was also associated with a statistically significant, approximately 77% median improvement in nerve fiber density as read histologically in a blinded manner from distal thigh sweat gland biopsy samples.

Further, in the first reported exploratory analysis of its kind, the degree of TTR knockdown observed in patients was shown to correlate with improvement in mNIS+7 scores, supporting the therapeutic hypothesis that reduction of mutant and wild-type TTR may be associated with potential halting of neuropathy progression in patients with hATTR-PN.

Importantly, patisiran was found to be generally well tolerated out to 25 months of treatment.  There were no drug-related severe adverse events (SAEs), and the majority of reported adverse events (AEs) were mild to moderate.  The most common drug-related or possibly drug-related AEs were flushing (22.2%) and infusion-related reactions, or “IRRs” (18.5%). All IRRs and drug-related flushing AEs were mild in severity and did not result in any discontinuations.  In addition, there were no clinically significant changes in liver function tests, renal function tests, or other laboratory or hematologic parameters, including platelets.

We believe these data bring us one step closer in solidifying patisiran’s potential as an innovative medicine for hATTR-PN, a progressive, debilitating disease with few treatment options.  We look forward to the continued advancement of patisiran as we strive to bring this novel investigational RNAi therapeutic to market and to improve the lives of patients with this devastating disease.