Viking Therapeutics Shares Rose 35.67% After VK2735 Maintenance Results

The September 22 move

Viking Therapeutics shares closed September 22, 2026, at $40.85, up $10.74, or 35.67%, from the previous session. The move followed Viking’s announcement of positive topline results from a study of less-frequent maintenance injections of its investigational obesity drug VK2735. The same-day release and reported market reaction identify the readout as the catalyst, although its precise contribution to the share-price change cannot be measured.

Trading volume reached 40.86 million shares, compared with 5.01 million on September 21, when the stock closed at $30.11. Viking also filed the results announcement with the Securities and Exchange Commission on September 22. The price and volume figures establish the scale of the response during the session; they do not measure how investors valued any individual study result.

What the maintenance study found

VK2735 is an investigational dual GLP-1/GIP receptor agonist that Viking is developing in injectable and oral formulations. In the approximately 180-person, randomized, double-blind, placebo-controlled VK2735-102 study, adults with obesity received 21 weeks of weekly injections. The study then assessed maintenance regimens over 12 weeks. Its stated objectives concerned safety, tolerability and pharmacokinetics; weight-change measures were exploratory endpoints.

At the end of weekly treatment, Viking reported approximately 16% to 19% mean weight loss across VK2735 dose groups, versus approximately 0% with placebo. The maintenance results measured how much of that earlier weight loss participants retained after their dosing schedules changed. Those percentages describe retained weight loss, rather than the share of participants who maintained it.

Participants assigned every-other-week injections retained an average of 90% of their earlier weight loss as a combined group. The highest-result individual every-other-week regimen retained 97%. The combined monthly group retained 85%, while its highest-result individual regimen retained 90%. Participants switched from active treatment to placebo retained 61%. The combined-group averages are the broader figures for each reduced-frequency schedule; individual maintenance regimens generally had efficacy groups of 10 to 16 participants.

A separate exploratory group of 13 participants continued 17.5 mg weekly injections through week 33. Viking reported 21.7% mean weight loss from baseline in that group. Viking also reported that gastrointestinal adverse-event rates during the 12-week maintenance period were not meaningfully different from placebo. These findings provide information on the regimens studied over that period; the readout does not establish how long the reported maintenance or tolerability would persist.

The placebo-controlled results support further testing of less-frequent injections after weekly treatment. Dosing flexibility could affect VK2735’s competitive position in obesity treatment, an interpretation described by Leerink Research analyst Thomas Smith. The study did not test whether a reduced injection schedule improves real-world adherence or whether VK2735 performs better than another obesity drug.

The development questions ahead

Viking’s larger injectable trials address a separate question. In its July 2026 corporate update, the company said the fully enrolled Phase 3 VANQUISH-1 and VANQUISH-2 trials would assess body-weight change against placebo after 78 weeks of once-weekly VK2735. The 12-week maintenance readout does not supply those trials’ efficacy or safety outcomes, and the cited update established no specific results date.

The next questions for maintenance dosing are whether weight-loss retention and tolerability persist beyond 12 weeks and whether the findings hold in larger, more medically varied populations. Viking has also described plans to study oral dosing in a second part of the maintenance study. Those results remain outstanding.

Viking said in July that it expected to initiate a Phase 3 trial of oral VK2735 in the fourth quarter of 2026. That timetable was a company plan, and the September maintenance results concerned injections after weekly treatment. The oral trial’s start and eventual results remain separate developments to assess.

MacroShed Markets is informational analysis, not investment advice.