Viking Therapeutics starts Part 2 of VK2735 trial testing oral maintenance dosing after injectable weight loss

Viking Therapeutics said on October 6, 2026 that it has started Part 2 of an exploratory maintenance dosing study of VK2735, its experimental dual GLP-1/GIP receptor agonist. The new portion tests whether people who lose weight on weekly injections can keep that weight off by switching to an oral tablet or to less frequent shots ^[1].

The trial is randomized, double-blind and placebo-controlled, and enrolls about 195 adults with obesity (BMI of 30 or higher) who are otherwise healthy ^[1]. Everyone starts the same way: weekly subcutaneous doses of VK2735 or placebo for 21 weeks. After Week 21, participants move to one of several maintenance options — daily oral doses, weekly oral doses, monthly subcutaneous doses, every-other-week subcutaneous doses, or placebo ^[1].

The stated objectives are safety, tolerability and the drug's pharmacokinetic profile, which describes how the drug moves through the body. Weight change is an exploratory endpoint only, measured both from baseline and from Week 21 to the end of the study at Week 33 ^[1]. In other words, this study is not designed to prove that any one maintenance regimen preserves weight loss.

How this fits with Part 1

Viking began the two-part maintenance program in 2025 ^[1]. Part 1 was described as a Phase 1 trial in roughly 180 adults with obesity, with a 19-week weekly injection period followed by maintenance regimens and a final visit at Week 31 ^[2][3]. The company's descriptions of Part 1's maintenance arms shifted slightly over time: the October 2025 announcement listed monthly subcutaneous, daily oral and weekly oral dosing plus placebo ^[2], while the January 2026 enrollment-completion release listed weekly, every-other-week and monthly subcutaneous dosing along with daily oral, weekly oral and placebo ^[3].

Viking said in April 2026 that Part 1 data were expected in the third quarter of 2026 ^[4], and the October 2026 release states that positive top-line results from Part 1 were "recently announced" for subcutaneous maintenance regimens ^[1]. Specific Part 1 numbers — such as how much weight was regained or maintained on each schedule — have not been disclosed in this announcement ^[1].

Chief Executive Brian Lian said the company is "eager to continue this study with the initiation of Part 2, which will explore multiple regimens, both oral and subcutaneous, with the potential to provide greater optionality and flexibility to best align with a patient's individual weight loss journey" ^[1]. Viking has argued that using the same molecule in pill and injection form may avoid problems that can come with switching between different drugs ^[3][4].

Why it matters for patients

Most approved obesity medicines are taken indefinitely at a steady dose. Semaglutide is sold as Ozempic, Rybelsus and Wegovy; tirzepatide is sold as Mounjaro and Zepbound ^[1]. A "start with a shot, maintain with a pill" approach is a different model, and if it works it could matter for people who dislike needles, who travel, or who struggle to stay on weekly injections. Lian framed the goal as adherence, saying flexibility and optionality are "key to increasing adherence to treatment and improving long-term weight management" ^[1].

The practical caveats are large. VK2735 is not approved in any form, in any country, and this maintenance study is exploratory, small and short — 33 weeks total, with about 195 participants ^[1]. It compares dosing schedules in healthy adults with obesity, not in people with the range of medical conditions seen in routine care. Whether oral maintenance holds weight off as well as continued injections has not been established.

What happens next

Viking expects to report results from Part 2 in 2027 ^[1].

Separately, two Phase 3 trials of subcutaneous VK2735 are fully enrolled: VANQUISH-1, with about 4,500 adults without type 2 diabetes who have obesity (BMI of 30 or higher) or are overweight (BMI of 27 or higher) with at least one weight-related condition, and VANQUISH-2, with about 1,000 adults with type 2 diabetes who have obesity or are overweight ^[1]. Earlier company statements had put the VANQUISH-2 target at roughly 1,100 patients ^[2][3]. Both studies randomize participants to weekly VK2735 at 7.5 mg, 12.5 mg or 17.5 mg, or placebo, for 78 weeks, with percent change in body weight at 78 weeks as the primary endpoint ^[1][4].

Viking also said in April 2026 that it planned to begin a Phase 3 trial of the oral VK2735 tablet for obesity in the fourth quarter of 2026, following an end-of-Phase 2 meeting with the FDA in December 2025 ^[4].