Viking Therapeutics (NASDAQ:VKTX) reported top-line results from a maintenance dosing study of VK2735, its dual GLP-1/GIP receptor agonist candidate for obesity, showing that participants retained much of their initial weight loss after transitioning from weekly treatment to every-other-week or monthly dosing schedules.
The study enrolled 180 adults with a body mass index of at least 30 and no other comorbidities. Participants were randomized across 11 treatment groups. During a 21-week induction period, patients received weekly subcutaneous VK2735 doses ranging from 15 mg to 22.5 mg, or placebo. They were then transitioned for 12 weeks to maintenance regimens that included weekly, every-other-week, monthly or placebo dosing.
Weight Loss During Induction
At week 21, weekly VK2735 dosing produced weight loss ranging from approximately 16% to 19%, compared with approximately 0% for placebo. All VK2735 dose groups separated from placebo beginning at week four, with reported p-values of less than 0.0001 for each dose level versus placebo.
Across the combined VK2735 treatment groups, Viking said:
- 98% of participants achieved at least 5% weight loss;
- 90% achieved at least 10% weight loss;
- 65% achieved at least 15% weight loss; and
- 32% achieved at least 20% weight loss.
By comparison, 13% of placebo participants achieved at least 5% weight loss, while no placebo participants reached the 10%, 15% or 20% thresholds at week 21.
Participants who continued on a 17.5 mg weekly dose throughout the 33-week study reached 21.7% weight loss from baseline, or 22% placebo-adjusted weight loss, according to the company. Lian said no plateau was observed at week 33.
Less Frequent Maintenance Dosing
Among participants switched from weekly dosing to every-other-week VK2735 treatment, the mean proportion of initial weight loss retained at week 33 ranged from 83% to 97%. That compared with 61% weight-loss retention among participants transitioned from 17.5 mg weekly VK2735 to placebo. Viking reported p-values below 0.01 for each every-other-week cohort versus placebo.
For participants switched to monthly dosing, mean retention of initial weight loss ranged from 82% to 90%, compared with 61% in the placebo-transition group. The company also reported p-values below 0.01 for each monthly maintenance cohort versus placebo.
Lian said the maintenance regimens represented dose reductions of as much as 85% for some participants, while still demonstrating a maintenance effect. He added that Viking has not yet selected doses for its planned extension studies and is awaiting feedback from the U.S. Food and Drug Administration on dose selection and frequency.
Tolerability and Development Plans
Viking said discontinuations due to adverse events during the induction period were low. The company reported that gastrointestinal adverse events, including nausea, vomiting, diarrhea and constipation, were generally consistent with its prior Phase II VENTURE study, despite a faster two-week titration schedule in the maintenance study compared with the three-week schedule used previously.
During the every-other-week and monthly maintenance periods, Viking said treatment-emergent adverse events and gastrointestinal events were generally low and not meaningfully different from placebo. Lian said the findings support the company’s view that VK2735’s pharmacokinetic profile, including an extended half-life, could provide dosing flexibility.
Dr. Lou Aronne, former president of The Obesity Society, said less frequent dosing could potentially help treatment persistence, which he characterized as important for long-term weight management. He also cautioned that comparisons with other therapies are limited because this was a smaller, earlier-stage study rather than a large Phase III trial.
Viking is currently conducting two fully enrolled Phase III trials of subcutaneous VK2735: VANQUISH-1 in adults with obesity and VANQUISH-2 in adults with obesity and type 2 diabetes. The company expects results from those trials in 2027. It also plans to begin two Phase III studies of an oral VK2735 formulation, designed to mirror the subcutaneous VANQUISH trials.
Lian noted that the results are preliminary top-line data and that Viking has not yet received or fully evaluated all study data. The company expects final results later this year and may present additional details at future medical meetings.
About Viking Therapeutics (NASDAQ:VKTX)
Viking Therapeutics, Inc is a clinical-stage biopharmaceutical company focused on developing therapies for metabolic and endocrine disorders. The company’s research programs target conditions including obesity, nonalcoholic steatohepatitis (NASH), metabolic dysfunction-associated steatohepatitis (MASH), dyslipidemia and other disorders involving hormone regulation and metabolism.
Viking’s lead program is VK2735, an investigational dual agonist of the glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) receptors being developed in injectable and oral formulations for obesity and related metabolic conditions.
