Ionis digs into phase 3 data ahead of Alnylam showdown

Ionis has sole control of the asset having been jilted by GlaxoSmithKline in August.

Ionis Pharmaceuticals has shared a closer look at phase 3 data on inotersen in patients with hereditary TTR amyloidosis (hATTR). The antisense drug triggered a 20-point improvement against a score of neuropathy impairment, laying a marker for the upcoming showdown with Alnylam.

Carlsbad, California-based Ionis posted top-line data from the trial in May. Back then, Ionis said the trial linked the transthyretin-targeting antisense drug to a statistically significant improvement in mean neuropathy impairment score—known as mNIS+7—after 15 months but didn’t discuss the numbers. 

Now, Ionis has disclosed a 20-point mNIS+7 improvement and accompanying 0.00000004 p value. Those involved with the study think the improvement is clinically meaningful. 

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“A 20-point benefit in mNIS+7 is unprecedented and could mean the difference between the ability to walk and being confined to a wheelchair for patients suffering from this debilitating and fatal disease,” Annabel Wang, M.D., an associate professor of neurology at the University of California and an investigator in the NEURO-TTR trial, said in a statement.

Ionis also trumpeted the fact the change in mNIS+7 reached statistical significance after eight months. That figure could play an important role in the coming months and years as Ionis seeks to paint inotersen as a better bet for hATTR patients than Alnylam’s patisiran, which came through its own phase 3 test last month.

RELATED: Alnylam’s patisiran hits all endpoints in critical phase 3

Alnylam is yet to present a close look at data from its trial. That is set to change at an ATTR meeting in Paris early next month that will provide an early yardstick for which company is likely to prevail. Alnylam’s presentation is scheduled for 11:00 a.m. Ionis will take the stage at 11:20 a.m.

For people seeking to read the tea leaves, the safety slides will hold as much interest as those on the efficacy of the rival drugs. Ionis’ stock has been rocked repeatedly by reports of low platelet levels and other serious side effects. Ionis has maintained that inotersen has a manageable risk profile, a position it again adopted for the latest data drop without providing safety data from the trial to support its position.  

The biotech is closing in on the day it has to make this argument to regulators. Ionis plans to file for approval before the end of the year. And, having been dropped by GlaxoSmithKline in August, it has sole control of the asset as it navigates the final few turns of the race to market.