Patrick Temple-West in New York Published September 14 2026 A resurrected class of obesity drug can help patients cut their weight without suffering the gastrointestinal side effects associated with the blockbuster drugs that lead the market. Corbus Pharmaceuticals, a Massachusetts-based biotech, has reported its daily pill delivered similar weight loss to Eli Lilly’s tablet Foundayo, but with fewer problems such as vomiting, nausea and constipation, in an early-stage trial of more than 200 obese people. The results, published on Monday, could herald a revival for a class of weight-loss drugs known as CB1 blockers, which were previously associated with severe psychological side effects.

The trial’s success opens a potential new front in the multibillion-dollar race to produce an obesity pill as effective as blockbuster GLP-1s, including Foundayo and Novo Nordisk’s Wegovy pill, but with less nausea and vomiting. CB1 drugs target receptors in the body that control how the body stores food as fat and play a role in controlling appetite. While trials have shown these drugs are successful in reducing weight, they have been largely abandoned by big pharmaceutical companies.

A version by French pharma group Sanofi was approved by the EU in 2006, but withdrawn two years later after the European Medicines Agency found the risk of psychiatric disorders roughly doubled in patients taking the pill compared with those taking a placebo. Novo Nordisk abandoned development of its own version of the compound in August after poor trial results, taking a DKr4bn writedown. In 2024, Novo reported mild to moderate psychiatric side effects associated with its CB1 testing, results that disappointed investors and sent the company’s shares down.

Corbus said it had fixed the original problems with CB1 blockers by preventing its own compound from travelling into the brain. “This initial data seems to indicate that our CB1-targeting drug has comparable weight-loss efficacy to the commercially available oral GLP-1s while delivering a very differentiated GI tolerability profile with markedly less vomiting and nausea,” Yuval Cohen, chief executive at Corbus, said in an interview. In its initial trial, Corbus tested people for 12 weeks and said people lost an average of 5 per cent of their body weight when adjusted for the placebo group. Eli Lilly has said people on its pill have lost the same amount at 12 weeks, increasing to about 10 per cent at their highest dosage at 72 weeks.

Eli Lilly’s pill was approved in April following Novo Nordisk’s oral drug, which won approval in early 2026. So far, US doctors have written more prescriptions for Novo’s pill than Lilly’s, industry data show. But Lilly has an advantage over Novo in US sales of injected diabetes and obesity drugs.

Pills comprise nearly 20 per cent of the obesity market versus jabs, according to Morgan Stanley research. Corbus is entering an increasingly crowded market for weight-loss treatments. It is competing with about a dozen other pills in various testing stages, including from Astra Zeneca as well as start-ups such as Kailera.

However the weight-loss opportunity for pharma companies remains immense. About 40 per cent of US adults are obese, according to government data. The global sales of obesity drugs could hit $105bn by 2030, according to Goldman Sachs.