Roche’s new weight loss candidate has the efficacy the Swiss pharma was looking for. But it also comes with a high rate of side effects that have plagued the drug category.
On Tuesday, the drug developer shared more details from a Phase 1b study that had an interim readout earlier this year. In the updated results, Roche said that patients on the 22 mg dose of the drug had an average weight loss of 18.9% at 24 weeks.
But the treatment, a GLP-1/GIP drug called CT-388, also had high rates of vomiting and nausea as patients worked up to the highest dose. During that 12-week period, more than 80% of patients experienced nausea and 75% reported vomiting. Those figures fell during a 12-week maintenance period to 54.2% and 33.3%, respectively.
Roche acquired CT-388 through its $2.7 billion deal for Carmot Therapeutics last year, which jump-started the company in obesity. There’s also CT-996, a pill-form drug from the deal that has caught investors’ eyes and is slated to have more data on Wednesday.
Tuesday’s Roche data were reported at the European Association for the Study of Diabetes annual meeting. In addition to the side effect and 24-week results, Roche said that CT-388’s 22 mg dose had an average weight loss of 12.4% at 12 weeks, and an 8 mg cohort had mean weight loss of 10.2% at the same point. The study was conducted out of a single site in Mexico.
Eli Lilly and Novo Nordisk have so far dominated the market for the new weight loss drugs, and their injected medicines have rapidly become blockbusters that are in so much demand the companies have struggled to make enough of them. Drugmakers like Roche are betting that a next wave of medicines will be pills that are more convenient for patients and easier to manufacture at greater scale. But in the increasingly competitive field, side effects — often vomiting, nausea and other forms of gastrointestinal discomfort — have become a growing point of differentiation, and in some cases led to the failure of programs.
Starting at a lower dose and titrating slower are “expected to further improve tolerability, as demonstrated with other incretin-based therapies,” Roche said. But the company also believes that the data warrant testing a higher dose in longer trials that have longer titration. More studies are already in the works, with a Phase 2 study recently initiated and plans that are ongoing for a Phase 3 study.
That new mid-stage study is planning to recruit some 450 patients and test five doses of CT-388. The primary endpoint of weight loss will be tested at the 48-week mark, twice as long as the 24-week point in the Phase 1b study.