Pfizer takes a step back in weight-loss race

Driving the news: The pharma giant took a step back on that front, announcing on Friday it was pulling the plug on Phase 3 studies for its twice-daily version of danuglipron, its oral weight-loss drug candidate.

• Pfizer's shares closed down 5.1%, and are now off over 50% from their peak, when the company's COVID vaccine drove revenue to record heights.
• Of note: This is Pfizer's second setback in the space this year, having abandoned development of lotiglipron, an experimental obesity and diabetes pill, in June.

Between the lines: Pfizer said a clinical trial of danuglipron showed the formulation was effective at shedding pounds, reporting a 13% body weight reduction at 32 weeks, though those results are smaller than those seen in trials of similar rival drugs.

• The bigger issue was the high rates of side effects; although they were "mild," they caused more than half the patients in the trial to drop out.
• Up to 73% experienced nausea, nearly half experienced vomiting, and 1 in 4 reported diarrhea.

Yes, but: Pfizer still believes there's a future for danuglipron, just in a different formulation that it hopes will be more tolerable.

• "We believe an improved once-daily formulation could play an important role in the obesity treatment paradigm, and we will focus our efforts on gathering the data to understand its potential profile," said Mikael Dolsten, the company's chief scientific officer of R&D, in a statement.

The bottom line: While Pfizer regroups, Eli Lilly and Novo Nordisk's lead remains unchallenged in what could be a $100 billion weight-loss drug market.

Go deeper: The big question about obesity drugs: Can people ever stop taking them?