The new drug is part of the second generation of weight-loss pills under development by companies including Eli Lilly and Novo Nordisk that will offer patients a more convenient alternative to injections.

Some analysts expect the weight-loss drug market, currently dominated by Novo Nordisk’s Wegovy and Eli Lilly’s Zepbound, to be worth more than US$150 billion in annual sales by the early 2030s.

Pfizer last year said it was focusing on the development of the reformulated version of danuglipron after it scrapped the twice-daily version because most patients dropped out of its mid-stage trial with high rates of side effects such as nausea and vomiting.

It had already dropped another daily weight loss drug, called lotiglipron, due to safety concerns as it raised levels of liver enzymes in some patients.

Shares of Pfizer rose 3.7% to US$29.30 in premarket trading.

The shares closed at US$28.35 on Wednesday and have lost more than half of their value since hitting US$61 in December 2021, due to a steep drop in sales of its Covid products and investor worries over its pipeline including lotiglipron.

Pfizer said on Thursday that early study results supported once-daily dosing, with no liver enzyme elevations observed in more than 1,400 healthy adult volunteers.

GLP-1s, originally developed for type 2 diabetes, mimic the action of the GLP-1 hormone to regulate blood sugar, slow digestion, and suppress appetite.

Other companies working on next-generation weight loss drugs include Amgen and Viking Therapeutics.

Sales of Pfizer’s Covid-19 vaccine and pill have fallen drastically from their peak during the pandemic, putting pressure on CEO Albert Bourla to drive growth through newer drugs.

The company on Tuesday announced that chief scientific officer Mikael Dolsten would step down after a more than 15-year stint with Pfizer.