Viking Therapeutics shares rose about 21%, to $36.47, by 10:39 a.m. ET Tuesday, up from Monday’s close of $30.11, after the company reported top-line results from a small study of its obesity drug VK2735. In the company-reported findings, people who had lost weight on weekly injections kept most of it off after switching to monthly or every-other-week doses.
What the study did
The study, called VK2735-102, is a randomized, double-blind, placebo-controlled trial in about 180 adults with obesity, defined as a body mass index of 30 or higher. According to Tuesday’s release, for the first 21 weeks participants were randomly assigned to weekly injections of VK2735 or placebo. (When Viking announced in January that enrollment was complete, it described a 19-week first phase.) VK2735 is what Viking calls a dual agonist of the GLP-1 and GIP receptors; doses were increased over time to 15, 17.5, 20 or 22.5 milligrams. After 21 weeks, participants lost about 16% to 19% of their body weight across the dose groups, compared with about 0% on placebo.
Then came a 12-week “maintenance” phase, through Week 33. Participants were switched to injections every other week, injections once a month, continued weekly dosing (a smaller, exploratory group), or placebo, to see how much of the Week 21 weight loss they kept. The company says the study’s stated goals were safety, tolerability and drug levels in the blood; weight change itself is described as an exploratory endpoint, not the trial’s main measure.
What the numbers show
Participants who switched to placebo during maintenance kept 61% of their Week 21 weight loss by Week 33 (27 people). Those switched to every-other-week dosing kept 90% of it, combining three dose arms with results of 83%, 90% and 97% (the 97% figure is from just 12 people taking a 10-milligram dose every other week). Those switched to monthly dosing kept 85%, combining arms that ranged from 82% to 90% (the 90% figure is from 11 people taking 17.5 milligrams monthly). Both combined groups did better than placebo by a statistically significant margin, according to the company.
A separate, smaller group of 13 people stayed on weekly 17.5-milligram dosing through Week 33; they had lost 21.7% of their body weight from baseline, versus a 0.3% weight gain on placebo — the basis for the release’s headline “22% placebo-adjusted” figure.
On safety during the maintenance phase, among people on every-other-week dosing, 1 of 37 stopped treatment early because of an adverse event, and nausea occurred in 2 of 37 (5%), described as mild. Among people on monthly dosing, 3 of 66 (5%) stopped treatment early, 1 of them (2%) because of an adverse event, and nausea occurred in 3 (4.5%), all mild. Viking says the rates of gastrointestinal adverse events in the treated groups were “similar to placebo.”
What the numbers don’t show
These are top-line, company-reported results that have not been peer-reviewed, and some of the dose arms behind the highest headline figures — the 97% and 90% numbers — involved as few as 11 or 12 people. Weight change was an exploratory endpoint in this study, not its primary goal. The results say nothing about Viking’s separate Phase 3 trial, VANQUISH-1, which finished enrolling about 4,650 patients in November 2025 and has no announced readout date.
Viking’s release quotes Louis Aronne, described as a former president of The Obesity Society, saying, “These results are important as they provide a basis for improved dosing flexibility for both clinicians and their patients.” The release discloses, in a footnote, that Aronne is a paid consultant to Viking.
The market
VKTX traded at $36.47 at 10:39 a.m. ET Tuesday, up about 21% from Monday’s $30.11 close. Earlier that morning, around 8 a.m. ET, a Yahoo Finance/Stocktwits report had put the stock up 38% in premarket trading. At the same 10:39 a.m. ET time, shares of Eli Lilly (LLY) were essentially flat, at $1,168.60 versus Monday’s $1,164.89 close, and Novo Nordisk’s American depositary receipts (NVO) were also little changed, at $39.73 versus $39.80.
What’s next
Viking says it plans an “upcoming part 2” of the study to test maintenance dosing with an oral, pill version of VK2735; the company has not given a date. The separate Phase 3 trial, VANQUISH-1, has no announced readout date.