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March 5 (Reuters) - Roche ROG.S said on Thursday its experimental obesity drug, coming from a partnership with Zealand Pharma ZELA.CO, helped patients lose up to 10.7% of their body weight in a mid-stage study.

In the 493-patient trial, the patients on the drug, petrelintide, lost far more weight over 42 weeks than those given placebo, who reported a 1.7% decline.

Roche gained access to petrelintide through a collaboration and licensing deal signed with Denmark's Zealand Pharma last year, giving the Swiss drugmaker shared development rights to the amylin-based obesity therapy.

The weight-loss drug market is surging, with biotech firms racing to win their share in a sector dominated by popular treatments Novo Nordisk's Wegovy NOVOb.CO and Eli Lilly's LLY.N Zepbound.

Unlike Wegovy and Zepbound — which target the GLP-1 hormone to reduce appetite — amylin-based drugs, such as petrelintide, activate receptors in the brain and slow gastric emptying with the potential for less severe side effects and preservation of muscle.

The mid-stage data from Zealand's study follows promising results for Lilly's amylin-mimicking drug candidate, eloralintide, announced in November.

Lilly's eloralintide helped patients lose as much as 20.1% of their weight in a mid-stage study after 48 weeks.

Analysts have previously estimated that weight loss in the range of 12% to 13% after adjusting for placebo would make Zealand's petrelintide competitive with Lilly's eloralintide.

Female participants in the trial lost considerably more weight than male participants, Roche said, though it did not provide specific figures.

A second mid-stage study in people with obesity or overweight and type 2 diabetes is expected to report results in the second half of 2026.

Genentech also plans to begin a separate study later this year testing petrelintide in combination with another experimental therapy, CT-388.