Viking drug maintains up to 97% weight loss on less frequent dosing

Shares of Viking Therapeutics surged in premarket and early trade after the company released topline results on its experimental obesity drug VK2735. Patients who moved from weekly injections to every-other-week dosing had maintained up to 97 percent of the weight they had already lost. Roche had released data the same day on its own obesity shot and Eli Lilly was breaking ground on a Houston manufacturing plant; neither matched the lift in Viking. The company set a conference call for 8:00 a.m. ET to walk through the full readout.

The Phase 2 maintenance trial enrolled 180 people with obesity and no related health conditions. They were randomized to one of four doses of VK2735 or to placebo and took weekly injections for 21 weeks, then stepped down to biweekly or monthly shots for another 12. The doses under test were 15.0, 17.5, 20.0, and 22.5 milligrams once a week, titrated upward from 1.25 milligrams at Week 1 through Weeks 13 and 14.

Induction alone moved the scale. After 21 weeks of weekly dosing the 15-milligram cohort had lost 16.3 percent of body weight, the 17.5-milligram group 17.8 percent, the 20-milligram group 18.7 percent, and the 22.5-milligram group 17.1 percent. Placebo lost 0.1 percent. The differences carried a p-value below 0.0001 against both baseline and placebo. Loss ran progressive in every active arm; nothing in the 21-week window suggested a plateau.

By the same checkpoint the combined VK2735 arms had already cleared the usual clinical thresholds in bulk. Ninety-eight percent of treated participants reached at least 5 percent weight loss, 90 percent reached 10 percent, 65 percent reached 15 percent, and 32 percent reached 20 percent. On placebo the same marks stood at 13 percent, zero, zero, and zero.

The maintenance window ran twelve more weeks. Monthly dosing kept up to 90 percent of prior weight loss. Patients switched to placebo retained only 61 percent over the same stretch. Every-other-week dosing maintained up to 97 percent of prior weight loss after 12 weeks.

An exploratory arm stayed on the weekly 17.5-milligram schedule. After 33 weeks those participants averaged about 21.7 percent loss from baseline, against a 0.3 percent gain on placebo. The data gave no signal of a plateau.

Brian Lian, Ph.D., chief executive officer of Viking Therapeutics, located the result in the molecule’s behavior in the body. Half-life is the time it takes for half a dose to clear the system. Pharmacokinetics is how a drug is absorbed, distributed, and eliminated. “The results of our innovative maintenance dosing study continue to demonstrate the significance of VK2735’s unique and differentiated half-life and PK profile, which appear to enable an effective new approach to achieving and maintaining the weight loss goals of patients living with obesity,” Lian said.

VK2735 is a dual agonist of the GLP-1 and GIP receptors. Those incretin pathways slow the emptying of the stomach and blunt appetite, the same broad mechanism now reshaping obesity care. Earlier weight-loss drugs were pulled for serious harms; even the successful weekly shots still collide with gastrointestinal side effects and the ordinary difficulty of staying on treatment month after month.

In this maintenance study the gut stayed quiet. One participant stopped for side effects during the induction phase, one in the every-other-week arm, and three in the monthly cohort. Gastrointestinal adverse-event rates through the twelve-week step-down window were comparable to placebo.

Lian put the tolerability beside the dosing result. “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. “Importantly, tolerability during the maintenance phase was excellent, with treated cohorts demonstrating GI-related adverse event rates that were similar to placebo.”

Louis Aronne, MD, FACP, former president of The Obesity Society and professor of metabolic research at Weill-Cornell Medical College, cast the maintenance numbers as a practical shift for the people writing the prescriptions. “These results are important as they provide a basis for improved dosing flexibility for both clinicians and their patients,” he said. “The cardiometabolic benefits of maintaining 75% or more of a patient's weight loss are becoming clearer, and these results demonstrating robust maintenance with reduced and less frequent doses are supportive of maintaining people within that margin through either monthly or every-other-week administration. Flexibility for patients and providers is paramount for achieving treatment persistence leading to the long-term benefits of weight control and these results are an important step in that direction.”

Same-day notes from the Street ran positive. Leerink Research analyst Thomas Smith called the data “stellar,” writing that they “build on [VK2735’s] potentially differentiated profile,” potentially allowing the drug to overcome some of the adherence issues associated with GLP-1 medications for obesity. Truist’s Gregory Renza measured the release against a crowded field. “The print clears our bar, drawing a healthy balance of inbounds with the data a point of interest among a dense obesity landscape… Tolerability came in clean, which we view as the piece that de-risks the step-down construct. 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,” Renza wrote.

Vomiting stayed in the single digits. The late-stage injectable rosters were already full. VANQUISH-1, the larger Phase 3 trial of injectable VK2735, had enrolled about 4,500 participants. VANQUISH-2 had enrolled about 1,000. Both studies had completed enrollment as of November 2025 and were testing weekly doses only up to 17.5 milligrams. Phase 3 is the late confirmatory stage of clinical testing, run at a scale large enough to show whether a medicine’s benefits and risks hold outside the earlier, smaller trials and to support a decision on approval.

The oral formulation moved on a different timetable. After discussions with the FDA, Viking expected the tablet version of VK2735 to enter Phase 3 in the fourth quarter of 2026. The dual agonist was in development as both a subcutaneous injection and a pill for metabolic disorders including obesity.