Zafgen Weight Loss Drug Shows Promise in First Human Test
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to get either a low, medium, or high dose of the new drug, or a placebo. The treatment was given as an intravenous infusion twice a week, for four weeks. Patients were allowed to eat normally, and weren’t counseled to combine drug treatment with exercise—which is often done in other studies, and can muddy up the final results. People in this Zafgen-sponsored study had a body-mass index of 32 to 45.
Researchers saw the best results at the highest of the three doses—0.9 milligrams per square meter of body surface area. People taking the Zafgen drug lost about 3.1 percentage points more of their body weight than those on a placebo after the first month, researchers said. Interestingly, scientists also saw progress on other important secondary measurements in the study. Hunger declined. So did the amount of triglyceride fats in the blood, along with so-called “bad” LDL cholesterol.
Sharp-eyed watchers of the obesity drug field might wonder what the big deal is about 3.1 percentage points of extra weight loss over placebo. The FDA, after all, has said it wants to see obesity drugs deliver an average of 5 percentage points of improved weight loss over placebo. But the FDA’s threshold is something developers need to reach after a full year of study. When Vivus and Orexigen’s drugs were compared with placebos after just their first month of study, Hughes says, they typically only offered a little more than 1 percentage point of weight loss advantage over placebo. So if Zafgen’s drug can continue at its current pace of weekly weight loss, it could help patients drop 20 to 40 percent of their weight in a six to nine month course of therapy, Hughes says.
That, of course, will need to be proven in further studies. Zafgen is already working on plans for a bigger, mid-stage clinical trial to confirm the weight loss results, Hughes says. The company has also reformulated its product into a more convenient form, an injection that can deliver the drug just under the skin, instead of via an IV infusion.
Zafgen envisions testing its drug in patients with the most severe forms of obesity—people with body mass indexes of 35 and above—and it’s likely to be the kind of thing taken under a doctor’s close supervision, Hughes says. Animal studies suggest the drug ought to work as well in men as it does in women, but Zafgen’s first study only enrolled women because they represent two-thirds of all severely obese people, and about 80 to 90 percent of that group that actually seeks medical treatment, Hughes says.
The company has enough cash to keep operating through this year, and to get its important Phase 2 clinical trial started, Hughes says. Zafgen is considering whether to develop the drug more on its own, or to seek help from a partner.
There’s no doubt this will give Hughes something of substance to talk about next week at the mother of all biotech partnering meetings—the JP Morgan Healthcare Conference in San Francisco. Hughes, not surprisingly, was keeping all his options open when asked about the future business strategy around this compound.
“Within a few months, we’ll know best path forward for the program,” he says.