AstraZeneca's Phase 3 Heart Disease Trial Hits, Teeing Up Pfizer Showdown in Japan

AstraZeneca has the data to mount an attack on Pfizer’s dominance of a heart disease market. Friday, the Anglo-Swedish drugmaker reported positive top-line results from a phase 3 trial of acoramidis in Japan, teeing it up to file for regulatory approval in the country.

Acoramidis, a TTR stabilizer, is already being reviewed by regulators in the U.S., where it is closing in on an approval in the heart disease transthyretin amyloid cardiomyopathy (ATTR-CM) that is tipped to drive blockbuster sales. BridgeBio Pharma is behind the push to bring acoramidis to market in the U.S., but AstraZeneca holds the Japanese rights. 

Alexion bought the Japanese rights to the candidate from Eidos Therapeutics, now part of BridgeBio, for $25 million upfront in 2019. The next year, Alexion began a phase 3 study in Japan and accepted a $39 billion buyout bid from AstraZeneca.  

Now, AstraZeneca has shared an update on the open-label phase 3 trial, reporting that the data “showed consistency” with the global results BridgeBio posted last year. The results were consistent with the larger data set across survival, cardiac-related hospitalizations, the six-minute walk test and quality of life at 30 months.

AstraZeneca is yet to share data from the clinical trial, with the results being held back for an upcoming medical meeting, but the comment about consistency with the BridgeBio study suggests it has the evidence to claim a piece of the Japanese ATTR-CM market. Pfizer won approval for tafamidis, the ATTR-CM therapy that it sells as Vyndaqel, Vyndamax and Vynmac, in Japan in 2019. 

Tafamidis sales (PDF) hit $3.3 billion in 2023, up 36% year on year, but Japan is a small part of the mix. The product generated sales of $251 million in Pfizer’s “developed rest of world” region, which covers Japan, Canada, South Korea, Australia and New Zealand, last year. Sales in that region fell 12% on an operational basis, but Pfizer has plans to drive growth.

Talking to investors on a quarterly results conference call this week, Alexandre de Germay, Pfizer’s chief international commercial officer at Pfizer, said (PDF) the ATTR-CM diagnosis rate in Japan is half that of France and the U.S. Pfizer has hatched a plan for increasing the diagnosis rate.

AstraZeneca could benefit from Pfizer’s efforts if it fulfills its ambition of bringing acoramidis to market in Japan and may also benefit from the comparatively slow start tafamidis has made in the country. Last year, analysts warned that Pfizer’s tafamidis was “quite entrenched” and “might be difficult to displace,” but those concerns may be less relevant in the relatively immature Japanese market.