Pfizer execs talk Metsera obesity drug

Pfizer made one thing clear this week: It’s officially back in the obesity race. 

The drugmaker is laser-focused on bringing to market treatments from its $10 billion acquisition of the obesity biotech Metsera. On Tuesday, it released promising phase two trial data on one injection, called PF′3944, that’s furthest along in development. 

The experimental drug drove solid weight loss when taken once a month in a mid-stage trial – offering early evidence that the injection can be administered less frequently than existing drugs without sacrificing efficacy. That could be a boon to Pfizer after it faced several setbacks in trying to win a slice of a market dominated by weekly injections from Eli Lilly and Novo Nordisk, along with Novo’s new daily pill. 

Patients with obesity or who are overweight lost up to 12.3% of their weight compared with placebo at week 28 in the ongoing phase two study. The company said no plateau was observed after patients transitioned to monthly dosing, which suggests that continued weight loss is expected as the study continues through week 64.

But investors are still looking for the full data from that trial, which is slated to be presented at a medical conference in June. Pfizer also plans to start 10 phase three studies on the injection, with the goal of achieving the first of several potential approvals in 2028. 

I talked to Pfizer CEO Albert Bourla and other top execs about the data this week and the company’s broader obesity strategy. Here’s what they had to say.

List said that’s one of the selling points of the company’s injection: it can serve as a more convenient maintenance treatment for patients to switch to. 

“If you say, listen, I can give you one of these drugs. This one, you’ll take once a week for the rest of your life. But this other one, you’ll take once a week, and you could also switch it to once a month. Which one do you want?” List said. “It’s always going to be the one with more options. 

He added that “weekly doesn’t work for everybody,” since some patients need to travel and can’t keep their injections refrigerated.

Bourla said people who have been taking weekly injections are also more likely to switch to another shot rather than an oral option. 

“The oral will be for people, but they didn’t start with the needle,” he said. “So as a result, I think the monthly or longer products will probably become a standard, and we are the first and hopefully the best.” 

“We’re expecting to get even more weight loss with that combination than we get with this GLP-1 alone,” he said. 

Amylin is hormone co-secreted with insulin in the pancreas to suppress appetite and reduce food intake. Amylin treatments have a similar effect to GLP-1s like Lilly’s Zepbound and Mounjaro, but some analysts and researchers say it could be easier for patients to tolerate and help them preserve lean muscle mass. 

Pfizer on Tuesday said early data showed that the two drugs together caused an additive weight loss of 5% when compared to placebo at day 8. Amylin alone also showed weight loss of 8.4% at day 36.  

Both drugs are ultra-long-acting, meaning they are engineered to remain active in the body for longer than existing treatments like Novo’s Wegovy and can be taken once a month. 

Pfizer plans to share more data on the amylin drug during the medical conference in June. List said the company is advancing the product into phase two trials in the first half of this year. 

Chief Scientific Officer Chris Boshoff told CNBC that the vast majority of patients will prefer an injection, and “obviously, being monthly will be preferable over weekly, and likely three-monthly maybe better than monthly.”

But List said it’s still early days for that drug.

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