Puretech’s Gelesis flunks the FDA’s key measure of success for weight loss treatments

PureTech portfolio company Gelesis says that their weight loss treatment failed a key measure of success in a pivotal trial but plans to try to hustle this along for a regulatory filing in any case with a hit on a co-primary endpoint measuring how many patients as a group were able to hit weight-loss goals measured by investigators.

On the one hand, 58% of the overweight subjects consuming its hydrogel capsule treatment dubbed Gelesis100 lost at least 5% of their body weight, compared to 42% of the placebo group. For the 10% mark, the split was 20% to 12%. But the treatment failed to break a minimal standard of efficacy, falling short of a 3% mean difference in weight loss with the placebo group.

Yishai Zohar, Gelesis CEO

The statement from Gelesis didn’t actually say what the mean difference was, with company executives holding that back for a scientific conference. Gelesis is run by Yishai Zohar, the husband of Puretech chief Daphne Zohar.

That outcome presents PureTech and the Gelesis crew with a thorny situation. A slate of three new weight drugs hit the market a few years ago after achieving the FDA standard of a 5% minimum mean difference in weight loss with placebos. They made it to the market, eventually, but then failed to gain much traction with only marginal evidence of efficacy.

While Gelesis would be touting some kind of advantage over exercise and dieting, it would presumably also try and present this as a safer alternative to what’s available now — if regulators give it a thumbs up.

Frank Greenway, the principal investigator in the GLOW study, had this to say:

As a physician, knowing that the majority of my patients could achieve clinically meaningful weight loss without some of the safety trade-offs makes me excited about this potential new approach.

Cambridge, MA-based PureTech is traded {LSE: PRTC} on the London exchange and was flashing a small gain by midday UK time, which later turned red.

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