Viking reports early VK2735 results testing less frequent weight-maintenance injections

Viking Therapeutics on September 22 reported preliminary results suggesting its investigational obesity drug VK2735 could preserve substantial weight loss with less frequent injections after an initial weekly treatment period. The findings address a practical drug-development question: whether treatment can become less burdensome once patients have lost weight.

According to the company, participants switching to every-other-week injections maintained up to 97% of their earlier mean weight loss over 12 weeks; those switching to injections every four weeks maintained up to 90%. These are sponsor-reported findings from an exploratory study, with limited follow-up.

### What the maintenance results measure

Participants had obesity, with a baseline body mass index of at least 30. After 21 weeks of initial treatment, the study tested different maintenance schedules. The combined every-other-week group included 37 participants and retained 90% of earlier mean weight loss, compared with 61% among 27 participants assigned to placebo.

Retention of earlier weight loss is a different measure from percentage reduction in starting body weight. Nor does a group average establish that every participant maintained the same benefit.

Viking previously described the maintenance program as an exploratory phase 1 study. Its development rationale was to test whether more flexible treatment schedules could support continued therapy. That is a hypothesis about treatment use as well as drug activity: demonstrating weight maintenance under study conditions does not establish that patients will remain on treatment longer in routine care.

### Earlier evidence supports activity, with limits

VK2735 targets the GLP-1 and GIP receptors. A separate, peer-reviewed phase 2 study, VENTURE, provides evidence of its weight-loss activity but does not validate the new maintenance schedules.

Published in Obesity in January 2026, VENTURE randomized 176 adults to weekly injections of VK2735 or placebo. Participants had obesity, or overweight with a weight-related condition; people with diabetes were excluded. The primary endpoint was percentage change in body weight after 13 weeks.

Mean weight reductions across active-treatment groups ranged from 9.1% to 14.7%, compared with 1.7% with placebo. The trial was funded by Viking. Its short duration and predominantly White, female population constrain conclusions about longer-term treatment and broader populations. Twenty-four participants discontinued treatment early, most commonly because of adverse events.

Those findings help establish why maintenance deserves testing. They cannot show which later treatment interval offers the best balance of efficacy, tolerability and convenience.

### Why sustained treatment matters

The maintenance problem is already documented for another drug in this class. In the peer-reviewed SURMOUNT-4 trial, reported online in December 2023, 670 adults who completed an initial tirzepatide treatment period were randomized to continue treatment or switch to placebo for another 52 weeks.

During that randomized period, participants continuing tirzepatide lost an additional 5.5% of body weight on average, while those switched to placebo gained 14.0%. The study demonstrates why researchers distinguish achieving weight loss from sustaining it. It does not establish that VK2735 will behave identically, or that less frequent treatment is equivalent to continued weekly therapy.

For healthspan research, the remaining questions extend beyond the scale. Longer trials must establish whether a maintenance strategy preserves clinically meaningful benefits, how adverse events evolve and whether results generalize to patients with different health conditions. A convenient schedule would be useful only if its benefits remain durable and its risks acceptable. The current evidence supports further investigation without establishing improvements in physical function, cardiovascular outcomes or longevity.