Viking begins study of less frequent VK2735 dosing for weight-loss maintenance
A company-run test of reduced-frequency dosing could show whether fewer injections can hold weight loss, but no data are available yet and VK2735 is not approved.
Viking Therapeutics has begun testing whether its experimental obesity drug VK2735 can maintain weight loss with less frequent dosing. The company started a Phase 1 dose-ranging study in October 2025 that explores "the feasibility of various VK2735 maintenance dosing regimens," including dosing every other week and once a month rather than weekly [1].
VK2735 is a dual agonist of the GLP-1 and GIP receptors, the same two hormone pathways targeted by tirzepatide (sold as Mounjaro and Zepbound). It is not approved for any use. Viking is developing it both as a subcutaneous injection and as an oral tablet [1].
In a quarterly update dated July 29, 2026, Viking said the maintenance study "continued to progress" and that results are expected "later this quarter," which places the readout in the third quarter of 2026 [1]. The company has not disclosed how many people are enrolled, which doses are being tested, how long participants are followed, or how maintenance is defined. No weight-loss results from this study have been reported [1].
Chief executive Brian Lian said the study is "designed to explore the effects of various maintenance regimens, including monthly and every other week dosing, to help us identify and optimize the individualized and long-term care often required to achieve and sustain a healthy weight" [1].
Viking's rationale is that flexible dosing over the long term "may improve treatment persistence" after people reach their weight-loss goals. The company also argues that staying on the same compound, in either tablet or injectable form, "may reduce the potential for undesired side effects compared with options that involve switching between different therapeutic agents" [1].
What is known about VK2735 so far comes from earlier trials. In the Phase 2 VENTURE study, adults with obesity who received 13 weekly doses had mean body weight reductions of up to 14.7% from baseline, with no signs of plateau, and the drug was described as safe and well tolerated, with most side effects mild or moderate [1]. Final results were published in January 2026 in Obesity, the journal of The Obesity Society [1].
Viking's Phase 3 VANQUISH-1 and VANQUISH-2 trials of the injectable are fully enrolled. VANQUISH-1 enrolled about 4,500 patients by November 2025, roughly five months after it began; VANQUISH-2 finished enrolling about 1,000 patients in the first quarter of 2026. Participants received weekly doses of 7.5 mg, 12.5 mg, 17.5 mg, or placebo for 78 weeks. The primary measure is percent change in body weight versus placebo after 78 weeks of treatment [1].
Viking also plans to start Phase 3 trials of an oral VK2735 tablet in the fourth quarter of 2026 [1]. In earlier oral testing, once-daily doses produced mean body weight reductions of up to 12.2% after 13 weeks, and up to 80% of treated participants lost at least 10% of their body weight, compared with 5% of those on placebo [1].
Viking reported $502 million in cash as of June 30, 2026, and said it appointed Hubert Chen as chief medical officer during the second quarter [1].
Why it matters for patients
People taking GLP-1 and dual GLP-1/GIP medicines for weight loss currently follow a fixed injection schedule, and the drugs are generally used long term rather than for a short course. If a lower dosing frequency could hold weight loss, it might mean fewer injections and less disruption over years of treatment. But that is exactly what this study is trying to find out, and the answer is not yet available. A Phase 1 trial is also an early-stage test, so even positive results would not by themselves prove the approach works.
Whether insurers or pharmacy benefit managers would cover a less frequent dosing schedule, and whether it would change cost, has not been reported [1]. The company has not said whether the goal includes reducing side effects, and no safety data from the maintenance study have been disclosed [1].
What happens next
- Maintenance-dosing results: expected in the third quarter of 2026; as of July 29, 2026, the company said it expected to report them "later this quarter" [1].
- Oral VK2735 Phase 3 trials: expected to begin in the fourth quarter of 2026 [1].
- VANQUISH Phase 3 primary results: measured after 78 weeks of treatment; a date has not been disclosed [1].
Sources
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