Ionis Pharmaceuticals shares fell over 8% in pre-market trade after the company said a phase 3 study of inotersen in patients with familial amyloid polyneuropathy met both primary endpoints but that adverse events were seen more commonly with inotersen. The company said that over the 15-month period of the study, inotersen-treated patients achieved statistically significant benefit compared to placebo. It said statistically significant differences were also observed for both endpoints at eight months.
Ionis said that two key safety findings were observed during the study that required changes to the monitoring schedule and that three serious adverse events of thrombocytopenia were observed in inotersen-treated patients while two patients recovered and one patient died due to intracranial hemorrhage. “One additional inotersen-treated patient discontinued treatment due to non-serious thrombocytopenia,” Ionis said. “Four inotersen-treated patients discontinued treatment due to a renal observation; two patients met a predefined renal stopping rule and two experienced serious renal adverse events, one of whom experienced chronic renal insufficiency. One placebo-treated patient also met a predefined renal stopping rule.”