Amgen said its experimental weight loss injection helped patients lose up to 20% of their weight on average after a year in a critical mid-stage trial. The company said it did not observe a plateau, which indicates the potential for further weight loss beyond 52 weeks.

Amgen's experimental drug MariTide led to an average weight loss of up to 20% in a year-long mid-stage trial of nearly 600 people who were overweight or obese, the company said on Tuesday.

After a research note raised potential safety concerns with Amgen's lead obesity candidate, the company defended its drug and has asked the journal to issue a correction and add in the finalized data.

Upcoming data from a mid-stage study of Amgen's experimental weight-loss drug MariTide will shed light on how well it might measure up against the popular GLP-1 drugs sold by Eli Lilly and Novo Nordisk .