The stock price of BridgeBio plunged 15% Thursday as Pfizer’s reported decision to withdraw a tafamidis patent in the European Union triggered fears of earlier generic entry in the blockbuster transthyretin amyloid cardiomyopathy (ATTR-CM) market.
During a hearing with the EU patent office, Pfizer decided to withdraw a patent coded EP3191461B1, which covers specific crystalline solid forms of tafamidis used in Vyndaqel (known as Vyndamax in the U.S.), according to a Feb. 5 note from Jefferies analysts.
While a three-member panel agreed that the patent was inventive, it questioned the patent’s novelty, according to Jefferies.
A Pfizer spokesperson confirmed to Fierce Pharma Friday that the so-called ’461 tafamidis polymorph patent was revoked by the European Patent Office on Feb. 5.
Through its partner Bayer, BridgeBio sells the direct rival small-molecule ATTR-CM treatment Beyonttra, known as Attruby in the U.S. Investors now fear that Pfizer’s setback could open the door for generic competition as early as 2028, putting pricing pressure on BridgeBio just three years into its drug’s launch.
While Pfizer’s patent strategy around tafamidis has largely been unclear, some investors have held the belief that a loss of market exclusivity will arrive in 2035, at least in the U.S. According to the FDA Orange Book, Vyndamax has a patent coded 9770441 governing the crystalline solid forms of tafamidis that extends into August 2035.
Thanks to an orphan market exclusivity, the ATTR-CM indication of Vyndaqel is protected from generic entry in the EU until February 2030, the Pfizer spokesperson said. The drug’s tafamidis compound patent has supplementary protection certifications lasting until November 2026 in most countries in Europe, according to the spokesperson.
Availability of generics to an established drug player is “typically a headwind to reimbursement, especially in European markets, where you have comparability pricing,” Leerink Partners analyst Mani Foroohar, M.D., said in a recent interview with Fierce on the ATTR-CM market.
Also known as reference pricing, the method allows EU members to benchmark costs among similar products.
But BridgeBio investors overreacted to the Pfizer news, according to analysts at Jefferies and Evercore ISI.
“Today’s news has zero impact on Attruby’s baseline assumptions, which already include [tafamidis] generic entry in Dec 2028,” the Evercore team, led by Cory Kasimov, wrote in a Feb. 5 note, adding that “there is no risk of earlier generic entry” per BridgeBio.
Kasimov and colleagues called Pfizer’s move a “strategic withdrawal” that provides “no legal precedent” because there wasn’t any regulatory ruling. They labeled the BridgeBio sell-offs “highly overdone and disconnected from fundamentals.”
Despite Pfizer’s decision to withdraw the ’461 patent, Attruby is becoming a first-line ATTR-CM option that could be differentiated from Vyndamax, Jefferies analyst Andrew Tsai said in his note.
For now, Tsai has arrived at 2034 peak sales of $4 billion to $5 billion for Attruby, assuming linear year-over-year growth without any acceleration from the med’s current growth momentum. For its part, Kasimov’s team argued that projected $3 billion revenue post-2028 in a “large ATTR-CM market may prove conservative.”
As the EU’s pricing policy compares similar drugs, any generic entry concerns would be irrelevant if Attruby could prove itself differentiated from Vyndamax.
That’s exactly the strategy BridgeBio is pursuing. The company has been digging into biochemical studies, data from clinical trials and real-world evidence to shore up Attruby’s profile.
“We continue to focus on differentiating [Attruby] as a best-in-class, first-line stabilizer,” BridgeBio CEO Neil Kumar, Ph.D., said in a November 2025 interview with Fierce.
He pointed to early separation of treatment effect between Attruby and placebo in BridgeBio’s phase 3 clinical trial compared with tafamidis in Pfizer’s trial. Patients who switched from tafamidis to Attruby in an open-label extension study also experienced greater stabilization of the TTR protein, which is known to offer certain cardiovascular benefits.
Kumar further noted that Attruby is the only ATTR-CM drug that has shown it could reduce not only the frequency of atrial-fibrillation-related hospitalization but also the incidence of new-onset afib events in ATTR-CM patients who had no prior history of afib, according to a phase 3 post hoc analysis.
Eventually, as Foroohar noted in his previous interview with Fierce, Attruby’s position will depend on the data that it can produce and whether payers will accept them as differentiated. While many physicians accept Attruby as a better stabilizer than tafamidis, Kumar said the question is still, “how much does that incremental stabilization get me in terms of less death and less hospitalization?”
The evidence BridgeBio provided so far has been extensive and supportive of Attruby, but it still lacks a prospective, head-to-head clinical trial. Since the two drugs are already very effective, to definitively show one is better than the other would require a large and lengthy study that Kumar said a company like BridgeBio can’t afford.
Editor’s note: This story was updated with additional details from a Pfizer spokesperson.