Indirect comparisons between BridgeBio’s Attruby and Pfizer’s tafamidis products showed a numerical survival benefit with the biotech’s drug.
BridgeBio’s transthyretin amyloidosis drug Attruby elicited notable improvements in survival and hospitalization rates, pointing to its potential “superiority” over competing products from Pfizer, analysts say.
In the Phase 3 ATTRibute-CM study, BridgeBio enrolled more than 630 patients with transthyretin amyloidosis cardiomyopathy (ATTR-CM), who were randomly assigned to receive either Attruby or placebo. An additional analysis of the trial, conducted by the Mater Misericordiae University Hospital in Ireland, employed anchored matching to indirectly compare Attruby to Pfizer’s tafamidis, marketed as Vyndaqel or Vyndamax.
Results of this matched analysis, disclosed Monday, showed that patients on Attruby had a 34% decrease in cardiovascular hospitalization versus tafamidis—an effect that was statistically significant. Attruby also lowered the risk of all-cause mortality (ACM) by 28% versus Pfizer’s product, though this benefit fell short of significance.
These findings provide “a glimpse of Attruby’s [potential] superiority in ATTR-CM,” analysts at Jefferies told investors in a note on Monday afternoon, “although cross-trial comparisons are a key caveat.” There are no direct head-to-head studies comparing Attruby to the tafamidis products.
Jefferies is expecting more than $3 billion in peak sales for Attruby given the current competitive landscape in ATTR-CM, but the analyst concedes that this estimate is “moot if Attruby proves differentiated” against Pfizer.
Aside from the indirect comparison against tafamidis, BridgeBio on Monday also presented biomarker data for Attruby, touting a significant increase in serum transthyretin while simultaneously minimizing variability in levels of the protein, which are two dynamics associated with ACM mortality risk, according to Jefferies.
Designed to be taken orally, Attruby is a transthyretin stabilizer that binds to the transthyretin protein and slows its breakdown, a process that otherwise drives the pathologic formation and accumulation of plaques across various organs in patients with ATTR-CM.
Attruby was approved in November 2024, putting it nearly five years behind the tafamidis franchise, which secured regulatory clearance in 2019. Last year, the tafamidis products hit nearly $1.7 billion in revenue worldwide, a 9% year-on-year increase. Attruby, meanwhile, clocked revenues of $362.4 million.
Pfizer has secured a few more years of market exclusivity for its tafamidis line. Last month, the pharma announced that it has reached settlement agreements with three generics manufacturers—Dexcel Pharma, Hikma Pharmaceuticals and Cipla—to keep their copycat products off the U.S. market through June 1, 2031. This patent extension could be worth as much as $6 billion for Pfizer.
