Biopharma pushes beyond GLP-1s, weight loss at ObesityWeek 2026

From Nov. 14 through 17, some of the country’s leading weight loss experts and biopharma companies with metabolic assets will gather in Washington, DC, for this year’s ObesityWeek, the annual scientific congress run by The Obesity Society.

“Heading into ObesityWeek, the giants Novo and Lilly will be mainly continuing to roll out their messaging as their challengers, both large and small, strive to gain attention with new or updated data from their pipeline contenders,” Jennifer Lilla, senior operations director at the market research firm CardioVascular Resource Group, told BioSpace over email.

Lilla is particularly excited about the next generation of offerings, many of which aim to improve the quality of weight loss and patients’ persistence on treatment. “Obesity Week is increasingly filled with novel preclinical and early clinical data, some of which represent potential up-and-coming mechanisms,” she said, pointing to emerging pathways to control weight, such as myostatin modulation and ALK7 inhibition.

“Poster sessions are often lively and data-rich, and ObesityWeek 2026 looks to be the same,” Lilla continued.

Of all the emerging pathways, “the next hot target” in obesity is amylin, as BMO Capital Markets’ Evan Seigerman said during a BioSpace webinar in September. While the currently dominant GLP-1 drugs—such as Novo’s Wegovy and Eli Lilly’s Zepbound—are effective, they don’t work equally for everyone and can carry tolerability issues such as nausea, vomiting, constipation and other gastrointestinal side effects.

In contrast, many experts believe that amylin could offer a safer alternative while also providing treatment options to more patients and helping others break through weight-loss plateaus.

“GLP-1s changed everything. And nothing,” Antoine Pivron, vice president of Withings Health Solutions, said in an email interview. While the drug class brought impressive weight loss numbers, the industry has now started to look for more, he continued, pointing to other key metrics such as how much of the weight lost is due to fat versus muscle.

“Weight was always the easiest signal to capture, not the most important one,” Pivron said.

These themes will take center stage at ObesityWeek.

Powerhouses face off in amylin arena

Novo will arrive at ObesityWeek with posthoc analyses of the Phase 3 REDEFINE 1 study, scheduled from Saturday through Monday, looking at the physical and psychosocial effects of CagriSema, as well as zeroing in on certain patient populations based on baseline body mass index and complications, Rodman & Renshaw told investors in an Oct. 28 note.

REDEFINE 1 tested CagriSema—a two-drug combo consisting of GLP-1 drug semaglutide and amylin analog cagrilintide—in patients with obesity or who are overweight and also have at least one weight-related comorbidity. REDEFINE 1 primarily assessed patients’ relative change in body weight and the percentage of participants achieving at least a 5% reduction in body weight.

Data released in December 2024 showed an average weight loss of 22.7% at 68 weeks in CagriSema-treated patients versus 11.8% and 16.1% in comparators given cagrilintide or semaglutide alone, respectively. Those on placebo lost 2.3% of their weight at this time point.

Despite the superior weight loss, investors were expecting weight reduction on CagriSema to hit 25% and were thus underwhelmed by these findings, sending the pharma’s shares down more than 20% the day of the readout.

Also bringing amylin data to ObesityWeek is Lilly, which is working on an asset called EloraTZP that combines the pharma’s GLP-1/GIP dual agonist tirzepatide with the amylin analog eloralintide.

On Saturday evening, the pharma will present preclinical data for this combo, demonstrating that in rats induced to have obesity, eloralintide used alongside tirzepatide resulted in stronger suppression of food intake than either drug given alone.

But Lilly has also generated clinical data for EloraTZP. Phase 2b data in September demonstrated average weight loss of up to 23.3% at 48 weeks in patients on EloraTZP, as compared with 14.8% with tirzepatide and 3% with placebo. Aside from hitting the primary endpoint of superior weight reduction over placebo, EloraTZP likewise led to better sugar control than tirzepatide alone or placebo.

This efficacy , however, came with safety tradeoffs. Across all EloraTZP doses tested, 10.8% to 27% of patients dropped out due to adverse events, versus 0% to 10.8% across different doses of eloralintide alone. Tirzepatide monotherapy and placebo had respective dropout rates of 2.9% and 16.7%.

Advancing a seemingly more tolerable amylin option are Roche and Zealand Pharma, which are collaborating on petrelintide. The partners in March touted “placebo-like tolerability” for petrelintide in the Phase 2 ZUPREME-1 study, with 4.8% of patients treated with the highest dose of petrelintide dropping out due to side effects, as compared with 4.9% for those on placebo.

But while the investigational drug was well tolerated, its efficacy results left analysts disappointed. The April readout presented weight loss data at 48 weeks, showing a 10.7% average reduction in the petrelintide group versus 1.7% in placebo.

Roche and Zealand will present posthoc subgroup analyses of ZUPREME-1 on Sunday afternoon at ObesityWeek, as well as results from a study that co-administered petrelintide with the pharma’s GLP-1/GIP dual agonist eniceptide.

“The amylin class will sort along a frontier of efficacy against tolerability,” Rodman & Renshaw wrote on Oct. 28. “Lilly sits at the high end of both which suggests a population willing to accept higher discontinuation for more weight loss, while petrelintide’s placebo-like tolerability positions it for patients who stop incretin therapy due to nausea and GI disturbance.”

Novo’s edge, meanwhile, is time, the firm said. The Danish powerhouse is closest to market, with a potential FDA approval for CagriSema as early as the fourth quarter. If approved, Novo “will set the first regulatory and pricing reference for the class before either Lilly or Roche reaches their respective Phase 3 readout,” Rodman & Renshaw said.

Quality, persistence as key battlegrounds

“Amylin is the science story. Weight loss quality is the real story,” said Withings’ Pivron.

On Saturday evening, Biohaven will present Phase 2 data for its myostatin/activin pathway inhibitor taldefgrobep alfa, an investigational therapy designed to reduce body weight while preserving lean muscle. Biohaven in March completed enrollment into a Phase 2 study of taldefgrobep alfa, testing weekly and monthly doses of the drug versus placebo in patients with obesity or who are overweight, looking primarily at the total change in weight over 24 weeks. Fat mass and lean mass are secondary endpoints.

There have been no data reveals yet from this mid-stage study, but Peter Ackerman, senior vice president of clinical development at Biohaven, told BioSpace in June that taldefgrobep alfa is meant to overcome the loss of lean muscle, a common stumbling block of GLP-1 therapies.

“If you can shut down both the myostatin and activin signaling pathway, we believe that you can optimize lean mass growth and optimize the reduction in fat mass,” he said. “We believe that we can bring higher quality of weight loss.”

Also presenting muscle-preservation data at ObesityWeek is Wave Life Sciences, according to an Oct. 28 note from Leerink Partners. Wave is working on the siRNA therapeutic WVE-007, which is designed to knock down the INHBE protein. Loss-of-function mutations in the gene encoding INHBE have been linked to better body composition. Wave’s presentation is scheduled for Sunday afternoon.

Wave will present interim Phase 1 data from the Phase 1/2a INLIGHT study at ObesityWeek. A readout in March showed that a 240-mg dose of the drug resulted in a 14.3% reduction in visceral fat at six months—a significant improvement from baseline. Participants receiving that dose saw a 5.3% drop in total fat and a 2.4% increase in lean muscle at that timepoint. In the higher 400-mg group, however, participants lost just 5% visceral fat and 1% of total fat, while also losing 0.2% lean mass. Wave’s shares crashed 54% in the wake of the data drop.

But these preliminary weight loss figures aren’t the trial’s primary endpoint, according to a clinical trials database. Rather, the main goal of the study was to demonstrate WVE-007’s safety. Wave said that WVE-007 was generally safe and well tolerated across treatment groups, including the even higher 600 mg dose, with no treatment discontinuations or serious treatment emergent adverse events.

Wave’s presentation at ObesityWeek “could provide an opportunity to share the 600 mg Phase 1 data expected in 4Q26,” Leerink wrote on Oct. 28. Findings from the Phase 2a portion of INLIGHT are expected by next year.

Aside from weight loss quality, Pivron contended that treatment persistence is also a crucial metric that is increasingly attracting attention. “Across the industry, roughly half of patients are gone within six months,” he said.“The question used to be ‘how fast can we hit the weight-loss target?’ Now it’s ‘do results hold, and are we reducing total cost of care or just adding a new cost line?’”

On this front, Leerink pointed to Rhythm Pharmaceuticals, which is set to present final Phase 3 data for its melanocortin 4 receptor agonist Imcivree (setmelanotide) on Monday afternoon in acquired hypothalamic obesity. Imcivree was approved for this indication in March, supported by data from the late-stage TRANSCEND trial, which found an 18.4% placebo-adjusted reduction in body mass index at 52 weeks.

“The 2-year data should provide greater clarity on the durability of treatment benefit, long-term safety and tolerability, and treatment persistence,” the firm said in its note. All of these “are critical to assessing setmelanotide’s long-term commercial potential.”