What happened

Shares of Bridgebio Pharma (BBIO 0.32%), a biotechnology company, are getting crushed after the company reported a disappointing trial failure. Investors mourning the end of the acoramidis program have hammered the stock 70.7% lower as of 11:11 a.m. ET on Monday.

So what 

Acoramidis is an experimental treatment that stabilizes a transport protein called transthyretin before it breaks up and leads to heart damage. Bridgebio Pharma stock is tanking today because a phase 3 trial with acoramidis and transthyretin mediated cardiomyopathy (ATTR-CM) patients suggests it doesn't improve outcomes nearly as well as the competition.

Investor watching a stock price fall.

Image source: Getty Images.

Vyndamax, a transthyretin stabilizer from Pfizer (PFE 0.05%) that the FDA approved to treat ATTR-CM patients in 2019, is already generating blockbuster sales. Today's disappointing results suggest acoramidis doesn't have a chance at challenging Vyndamax's lead in this niche. Six-minute walking test scores for patients treated with acoramidis declined by nine meters after 12 months of treatment. The placebo group declined by only seven meters.

Now what

This trial flop looks like a case of poor patient selection during the enrollment process. Vyndamax significantly improved six-minute walking test scores for ATTR-CM patients, but these were very different patient populations. At 12 months the average score in the placebo group had dropped by around 60 meters, not seven.

Regardless of the reasons for the flop, the data reported today can't be unseen. That means Bridgebio will most likely relegate acoramidis to a back burner. Luckily, Bridgebio has at least four clinical-stage pipeline catalysts beyond acoramidis expected in 2022 that could help the biotech stock recover from today's losses.