Watch out Alnylam/Ionis: Pfizer’s positive PhIII tafamidis data makes drug a new rival

Pfizer $PFE reported out some good news from a late-stage trial testing its drug tafamidis against a rare condition that leads to heart failure. The positive results of the Phase III study have both Alnylam $ALNY and Ionis $IONS investors squeamish, as it could be competition for patisiran and inotersen.

Brenda Cooperstone

The Pfizer trial, called ATTR-ACT, tested its drug tafamidis in patients with transthyretin cardiomyopathy, an inherited condition in which proteins don’t fold into their normal shapes correctly. The misfolding makes them build up and cause damage to the nerves, heart, and other organs. In the trial, the drug met its primary endpoint, Pfizer said, and demonstrated a statistically significant reduction in the combination of all-cause mortality and frequency of cardiovascular-related hospitalizations compared to placebo at 30 months.

Following news on the data, Alnylam stock fell 5%, potentially on fear of an upcoming rival as the pharma company is also pursuing a cardiomyopathy application for patisiran. And Ionis, which owns a majority stake in its spinout Akcea (which is developing inotersen for the same condition), also sank 5%.

Pfizer landed tafamidis when it acquired FoldRx in a buyout back in 2010 as it pushed into the rare disease field. Like other pharma companies, Pfizer was lured by the prospect of big returns for drugs that meet an urgent need in tiny patient populations.

Pfizer tested the drug in a rare neurodegenerative disease called TTR-FAP, but got rejected by the FDA in 2012 after trying to gain approval with only one trial as proof of the drug’s efficacy. Tafamidis was approved in 40 countries — including the EU in 2011 — however. It sells under the brand name Vyndaquel.

In a statement earlier this year, Pfizer said it’s still working on a way forward in the US for tafamidis in TTR-FAP.

“As a leader in TTR amyloidosis, Pfizer Rare Disease continues to partner with the FDA regarding a potential path to approval for tafamidis for TTR-FAP, as we hope to achieve the objective of providing TTR-FAP patients living in the United States with the same treatment option as those patients living in many other parts of the world.”

For now, tackling transthyretin cardiomyopathy gives the drug a new avenue for revenue generation in the US. Brenda Cooperstone, SVP and chief development officer in Pfizer’s rare disease unit, had this to say about the recent Phase III data:

These topline results are important for people with transthyretin cardiomyopathy and bring us one step closer to realizing the potential for a new treatment for those in desperate need. Pfizer Rare Disease has been at the forefront of improving the understanding of transthyretin cardiomyopathy, and we thank the patients who participated in the trial and their families, as well as the physicians and investigational sites that contributed to this important study. We look forward to sharing the detailed results of the study with the cardiovascular community and discussing these data with health authorities to determine an appropriate regulatory path forward.


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Research Scientist - Immunology
Recursion Pharmaceuticals Salt Lake City, UT
Director of Operations
Atlas Venture Cambridge, MA

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