AstraZeneca and Ionis Pharmaceuticals have breezed past another marker on the route to approval of eplontersen, revealing that the challenger to Alnylam’s Amvuttra and Onpattro improved outcomes in a rare disease out to 66 weeks.
Last year, AstraZeneca, which paid Ionis $200 million upfront for rights to its ligand-conjugated antisense candidate, reported that a phase 3 trial in hereditary transthyretin-mediated amyloid polyneuropathy (ATTRv-PN) hit three co-primary endpoints at an interim 35-week analysis. The partners raced the data to regulators and recently secured a December 2023 approval decision date from the FDA.
In parallel, the collaborators have continued to track participants in the phase 3 study. The latest update shows statistically significant changes on the co-primary endpoints seen at the interim analysts persisted out to 66 weeks.
The co-primary endpoints looked at the concentration of serum transthyretin—the protein that drives the rare health condition—a measure of neuropathic disease progression and a patient-reported quality of life questionnaire. AstraZeneca and Ionis shared some of the numbers behind the hits on co-primary endpoints last year, but the latest update is devoid of data. Safety was consistent with the 35-week data.
Publication of 35-week and 66-week data is planned for next month. The presentation at the American Academy of Neurology Annual Meeting could shed light on how competitive eplontersen will be against rival therapies.
Alnylam already sells two products, Amvuttra and Onpattro, for the treatment of polyneuropathy caused by hereditary ATTR. Sales of Onpattro, the older drug, hit $558 million last year, but hundreds of patients have now switched to Amvuttra. Sales of the newer drug were $94 million in its first year on the market.
A recent filing for FDA approval of Onpattro in the cardiomyopathy of ATTR amyloidosis could open up a bigger market for Alnylam. Strong uptake of Pfizer’s Vyndaqel products in cardiomyopathy drove sales of the family of medicines up to $2.4 billion last year. Alnylam and AstraZeneca, which is running a phase 3 trial in the cardiomyopathy indication, are both working to launch challengers for the blockbuster niche.