Pfizer reports promising results with monthly obesity injection

Pfizer’s experimental obesity drug shows promising results in a mid-stage clinical trial. Studies indicate that the drug leads to significant weight loss when administered once monthly, CNBC reports.

The company reported that in patients with obesity or overweight participating in Phase 2 of an ongoing study, a body weight reduction of up to 12.3% compared to placebo was recorded at week 28. In an analysis of all enrolled patients, regardless of whether they discontinued treatment, the weight reduction reached up to 10.5%.

According to Pfizer data, no plateau in effect was observed after switching from weekly to monthly dosing, suggesting that weight loss may continue into the later stages of the study, which will continue until week 64.

The results provide early indications that the injectable therapy can be administered less frequently than currently available drugs without compromising efficacy. This could prove to be a significant advantage for Pfizer as it seeks to enter a market dominated by weekly injections from Eli Lilly and Novo Nordisk, as well as Novo’s new daily pill.

While it remains unclear to what extent Pfizer might capture market share from established competitors, the potential for monthly administration may offer a more convenient alternative for patients.

“These top-line results confirm the potential of PF′3944 as a monthly therapy with competitive efficacy,” said Dr. Jim List, Pfizer’s Chief Medical Officer for Internal Medicine.

The company plans to launch up to 10 Phase 3 clinical trials with the drug, known as PF′3944, as early as this year. During prepared remarks for the company’s financial report, Chief Scientific Officer Chris Boshof indicated that modeling shows the possibility of achieving up to 16% weight loss at week 28 with a higher monthly dose in late-stage trials.

The news of the clinical results was announced on the same day Pfizer published its fourth-quarter financial results, which exceeded analyst expectations. Nevertheless, the company’s shares fell by nearly 3% in pre-market trading.

The injectable drug is an ultra-long-acting GLP-1 agonist designed to remain active in the body longer compared to existing therapies such as Wegovy. Pfizer is developing the medication for both weekly and monthly administration, including combinations with other therapies targeting various gut hormones.

Within the study, patients initially received weekly injections for 12 weeks before switching to monthly dosing. The goal was to determine if weight loss could be maintained with less frequent administration and if higher monthly doses were tolerable.

The treatment was generally well-tolerated, with the most common gastrointestinal adverse reactions being mild to moderate. Pfizer reported that no new safety concerns were identified.

The company has selected two monthly maintenance dosing regimens—low and medium—which will be tested in Phase 3. During Phase 2, a total of five patients discontinued treatment due to adverse reactions during the weekly phase, and another five after switching to monthly administration.

In a separate mid-stage study conducted last year, Metsera, the company from which Pfizer acquired the drug, reported that the highest dose led to an average weight loss of 14.1% after 28 weekly applications.