Ionis safety issues are a win for Alnylam

Dive Brief:

  • Ionis Pharmaceuticals’ stock dropped pre-market on Monday morning after the company announced Phase 3 data that showed some worrisome safety issues.
  • The biotech unveiled results from the Phase 3 NEURO-TTR study of inotersen, also known as IONIS-TTRRx, in patients with familial amyloid polyneuropathy (FAP).
  • The study showed inotersen achieved statistically significant results compared with placebo on both the modified Neuropathy Impairment Score +7 (mNIS+7) and the Norfolk Quality of Life Questionnaire-Diabetic Neuropathy (Norfolk QoL-DN).

Dive Insight:

While the study can be seen as a success because it hit both primary endpoints, the safety data that was spelled out by the company bothered investors and will likely make approval harder to obtain.

According to Ionis, there were two safety issues that occurred during the trial. As seen previously, three patients experienced severe thrombocytopenia; two of those patients recovered and the third died of an intracranial hemorrhage. A fourth patient discontinued the study due to the thrombocytopenia issue.

Something to note: the drug was previously put on clinical hold in April 2016 by the Food and Drug Administration due to a safety issue with thrombocytopenia, or severe declines in platelet counts, causing partner GlaxoSmithKline to push away from the collaboration.

The other, unexpected safety issue that cropped up was with renal problems. Four patients on the drug discontinued the study due to the problem.

The safety issues pushed the company to enhance safety and monitoring protocols in the study. All the adverse events occurred before the changes to the study.

Ionis emphasized 80% of patients completed the study and 95% of those patients participated in the open-label extension study.

Ionis plans to submit an application to the FDA and GSK still holds an option to license the drug after reviewing the data and the completion of the submission.

While Ionis stock fell in early morning trading, competitor Alnylam Pharmaceuticals, which is developing a similar drug dubbed patisiran, gained almost 17%. While Alnylam has reported safety issues of its own for patisiran, the strength of the efficacy for the Ionis drug helps to validate the approach. 

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Filed Under: Clinical Trials
Top image credit: Dollar Photo Club