Pfizer's Monthly Obesity Drug PF'3944 Shows Promising Mid-Stage Results
Pfizer has announced positive results from a mid-stage trial of its experimental obesity drug, PF'3944, which was acquired through Metsera. The drug demonstrated significant weight loss when administered once monthly, positioning it as a potential new option in the competitive weight-loss market.
Key Trial Results
Patients with obesity or who were overweight experienced up to a 12.3% weight reduction from baseline, compared to a placebo, at week 28 of the ongoing Phase 2 study. When including all patients, regardless of discontinuations, the weight loss was up to 10.5%.
The study indicated no plateau in weight loss after patients transitioned to monthly dosing, suggesting potential for continued reduction through the study's duration.
A Convenient Monthly Option
The prospect of a monthly injection could offer a more convenient treatment option for patients, differentiating it from existing weekly injections offered by companies like Eli Lilly and Novo Nordisk.
"These results support PF'3944's potential as a competitive monthly treatment." — Dr. Jim List, Pfizer's chief internal medicine officer.
Future Development & Potential
Pfizer plans to initiate 10 Phase 3 trials for PF'3944 this year. Chris Boshoff, Pfizer's Chief Scientific Officer, indicated that modeling suggests a higher monthly dose, planned for late-stage trials, could achieve 16% weight loss at week 28.
Drug Mechanism and Dosing
PF'3944 is an ultra-long-acting GLP-1 drug, designed for extended activity in the body. It is being developed for both weekly and monthly injection, as well as in combination with other treatments.
The Phase 2 trial involved an initial 12-week period of weekly injections before patients switched to once-monthly dosing.
Safety and Tolerability
The drug was generally well tolerated by patients. Most gastrointestinal side effects reported were mild or moderate, consistent with other GLP-1 class drugs. No new safety issues were identified.
Pfizer selected two monthly maintenance dosing regimens (low and medium) for further testing in Phase 3 trials. Ten patients discontinued treatment due to side effects across the weekly and monthly phases of the Phase 2 trial.
Market Reaction and Prior Data
These trial results were released on the same day Pfizer reported fourth-quarter earnings and revenue that exceeded expectations. Despite the positive drug news, Pfizer's shares decreased nearly 3% in premarket trading following the announcements.
A separate mid-stage trial last year, conducted by Metsera, had previously shown the highest dose of the injection resulted in an average weight loss of up to 14.1% after 28 weekly doses.