The 60-week trial recruits 450 patients and runs until 2028
Novo Nordisk has launched a late-stage trial testing smaller doses of its Wegovy pill, seeking the lowest maintenance dose that still keeps weight off.
The OASIS-5 study began on August 12 and runs until 2028, according to a US clinical trials database reported by Reuters.
It will test lower strengths of the daily maintenance dose against a current approved long-term dose of 25 milligrams.
"Having a broader range of maintenance doses could provide greater flexibility in treatment and optimising the patient experience," Novo said in an emailed statement to Reuters.
The 60-week trial will recruit 450 adult participants who have previously struggled to lose weight, with a body mass index of 30 or above, or 27 with a weight-related health issue.
The main goal is to test whether lower doses of oral semaglutide produce more weight loss than a placebo, with waist size, other health benefits, and side effects tracked as secondary goals.
Novo has not specified the dose strengths being tested.
The Wegovy pill is also approved at 1.5 mg, 4 mg, and 9 mg.
Patients have already been taking lower-than-approved doses on their own, driven by the high cost and side effects of GLP-1 medicines.
"People are using low dosages of these products... they just decide on their own," Novo chief executive Mike Doustdar told Reuters last week, noting that patients often seek health benefits beyond weight loss.
He expects market segmentation to prevent a winner-take-all battle with Eli Lilly.
Lilly did not immediately respond to a Reuters request for comment on whether it plans to test smaller doses of its oral drug Foundayo, which has lowest approved doses of 0.8 mg and 2.5 mg.
Novo is working to recover ground lost to Lilly in an obesity drug market projected to exceed US$100bn by 2030, Reuters reported.
The Wegovy pill brought in second-quarter sales of 3.22bn Danish crowns (US$499.89m).
Gastrointestinal side effects, including nausea, constipation, diarrhoea, and vomiting, remain the most commonly reported drawback of incretin-based therapies, the Financial Times reported.
One London-based advertising executive who took Mounjaro told the paper she felt mild nausea within 20 minutes of her first injection, and had stomach pain, bad breath, and burping even while microdosing at 0.25 mg.
Most leading candidates in development target receptors for amylin, a pancreatic hormone that promotes satiety by binding to different parts of the brain than GLP-1 drugs do, according to the Financial Times.
Zealand Pharma is developing petrelintide with Roche, which licensed the candidate last year in a deal worth up to US$5.3bn.
Mid-stage results in March showed average weight loss of 10.7 percent after 42 weeks with side effects similar to placebo, and shares in the Danish biotech fell by a third because the result trailed the up to 25 percent achievable with existing drugs.
Novo's semaglutide has already lost patent protection this year in Canada, India, China, Brazil, and Turkey, the Financial Times reported.
Its CagriSema combination delivered average weight loss of 22.7 percent and was submitted to the US Food and Drug Administration in December.
Lilly's retatrutide delivered 28 percent after 80 weeks at the highest dose, the largest of any medicine so far, though 11 percent of patients discontinued because of side effects.
