Viking Therapeutics’ VK2735 met Truist’s “best-case scenario,” with robust weight loss that was largely maintained when patients transitioned to less frequent dosing. Viking’s stock popped more than 30% on Tuesday.
Viking Therapeutics’ injectable GLP-1/GIP dual agonist elicited 17.7% weight loss after 21 weeks—and the efficacy held up under less frequent dosing regimens, supporting the candidate’s potential in a maintenance setting.
The Phase 1 topline readout “landed in the best-case scenario we had framed,” Truist Securities analysts wrote in a note Tuesday morning, “with wk 33 depth, retention and tolerability all clearing our bar.” Meanwhile, analysts at William Blair said the new data achieved a “maintenance trifecta,” retaining weight loss with benign tolerability and demonstrating weekly dosing indicative of a differentiated profile.
William Blair had previously anticipated these data as “the most impactful catalyst in 2026” for Viking. The company’s stock was trading up nearly 24% to $37.49 when the market opened on Tuesday.
The placebo-controlled study randomized around 180 adults with obesity to receive weekly doses of VK2735 or placebo for 21 weeks. At that time point, patients taking 17.5 mg of VK2735 lost an average of 17.7% of their body weight. Participants were transitioned to a range of maintenance dosing options including monthly, every other week, or weekly subcutaneous injections of the treatment or placebo.
Up to 97% of weight loss was maintained following a transition to every other week dosing for three months compared to 61% mean weight loss maintenance for the placebo cohort, Viking reported Tuesday. Up to 90% weight loss was maintained after participants transitioned to monthly dosing for the same period of time. An exploratory control arm that continued receiving weekly doses of VK2735 saw 21.7% weight loss compared to 0.3% weight gain for placebo comparators.
“Weight loss in this cohort was progressive through 33 weeks of treatment with no plateau observed,” Viking said in its announcement, adding that the 22% weight loss could improve over time.
“Due to the progressive nature of observed weight loss, the company believes that continued weight loss is likely to be observed with longer-term once-weekly dosing, as suggested by results from the exploratory control cohort in the maintenance phase,” the company said.
As for safety, rates of gastrointestinal-related adverse events were comparable to placebo during the 12-week maintenance dosing period, according to the press release.
Truist in its note also pointed to “clean” tolerability. “GI events through the maintenance window were not meaningfully different from pbo, with vomiting in the single digits across both step-down regimens and no moderate or severe nausea reported,” the analysts said. Truist views this result “as the piece that de-risks the step-down construct.”
For his part, Viking CEO Brian Lian indicated that Tuesday’s results support a maintenance strategy.
“We believe this dose-ranging study clearly demonstrated the potential viability of novel, extended dosing approaches for maintenance following induction with an incretin-based therapy,” he said in a prepared statement.
Viking’s VK2735 program—which also includes a pill form of the candidate—has been highly anticipated by analysts.
In June, William Blair analyst Andy Hsieh in an email to BioSpace named VK2735 as one of the obesity hopefuls likely to catch up to frontrunners Eli Lilly and Novo, with a chance to potentially overtake Boehringer Ingelheim’s a GLP-1/glucagon dual agonist licensed Zealand Pharma.
A Phase 2 trial of the oral form of VK2735 failed to excite investors in August 2025, showing 10.9% placebo-adjusted weight loss at 13 weeks. While the results were largely in line with other oral weight loss candidates, the market reacted to the safety profile: 20% of patients treated with oral VK2735 dropped out of the study due to side effects, compared with 13% of those on placebo. Viking’s stock crashed by around 40% following the readout.
