Patisiran, which is intended for the rare and progressive disease hereditary ATTR amyloidosis with polyneuropathy, is “the first ever positive Phase 3 results for an RNAi therapeutic, marking the potential arrival of an entirely new class of medicines,” said Alnylam ALNY, +52.04% Chief Executive John Maraganore.

The Wednesday news is a “big win for ALNY and RNAi,” especially after Alnylam halted a hemophilia drug’s development earlier this month and was forced to discontinue another Drug last fall, said Leerink Partners analyst Paul Matteis.

The results also appear to be a best-case scenario for the company, he said, noting that the safety data overall look “clean and sufficient to quell any concerns of revusiran,” which was discontinued last fall after patient deaths.

Individuals with ATTR amyloidosis have abnormal proteins in their body that can then damage bodily functions, affecting the heart and nervous and gastrointestinal systems.

Safety issues were also largely similar between the therapy and the placebo, except for mild-to-moderate peripheral edema, or swelling in the arms and legs, and infusion-related reactions, both of which were more commonly seen in patients on patisiran.