Rhythm Pharmaceuticals' Oral Obesity Drug Shows Promise in Phase 2 Trial

Rhythm Pharmaceuticals has made significant strides in its efforts to develop an oral treatment for obesity, with its phase 2 trial of bivamelagon hitting its primary endpoint. The results have sparked investor interest, sending the company's stock up by 26%.

Trial Results and Comparison to Existing Treatment

The phase 2 trial involved 28 participants with acquired hypothalamic obesity, a condition resulting from injury to the hypothalamus. Patients were randomized to receive one of three doses of bivamelagon, an MC4R agonist, or a placebo. After 14 weeks of oral dosing, the study revealed dose-dependent BMI reductions of up to 9.3% in the treatment group, compared to a 2.2% increase in the placebo arm.

These results are comparable to data from previous trials of setmelanotide, Rhythm's injectable treatment marketed as Imcivree. Phase 2 and 3 trials of setmelanotide reported BMI reductions of 9.7% and 10.5% after 12 and 16 weeks of treatment, respectively.

Safety Profile and Future Development

The safety profile of bivamelagon appears promising, with only one patient discontinuing treatment due to rectal bleeding. Three patients in the treatment group and one in the placebo group reported mild, localized hyperpigmentation. Notably, the lack of significant hyperpigmentation was cited as a strength of bivamelagon when Rhythm licensed the drug candidate from LG Chem last year.

Rhythm is addressing potential compliance issues related to the current dosage form, which requires patients to swallow three large pills daily. The company is developing a new, smaller tablet to improve patient adherence.

CEO David Meeker, M.D., indicated that Rhythm is in discussions with the FDA regarding the initiation of a phase 3 trial, potentially starting next year. The company is hoping for a six-month double-blind period but expects to need one year of safety data.

Strategic Positioning and Market Outlook

Rhythm is positioning bivamelagon as part of a two-pronged approach to next-generation obesity treatments. Alongside the oral medication, the company is developing RM-718, a weekly subcutaneous MC4R agonist. Meeker expressed confidence that patients will prefer these new options over the current daily injectable, Imcivree, even when generic competitors enter the market.

The positive trial results and strategic development plans have resonated with investors, with Rhythm's stock opening up 26% at $82.18 in early trading following the announcement.