Viking's VK2735 Maintenance Data Delivers: Up to 97% Weight-Loss Retention on Biweekly Dosing, No Plateau at Week 33 — Then a $500M Raise Cools the Stock
Viking Therapeutics (NASDAQ: VKTX) reported positive topline results from its randomized maintenance study of VK2735 (dual GLP-1/GIP agonist) on September 22, 2026 — the Q3 readout this topic had been watching. The stock surged as much as 36% intraday, then gave much of it back two days later when the company priced an upsized $500M offering of common stock and convertible senior notes at $35.00/share (~16% discount); shares closed September 26 week at $35.56, still +22.7% over five days (/markets/VKTX/2026/09/28).
The induction phase (weeks 0–21): Weekly VK2735 at 15/17.5/20/22.5 mg produced 16.3%/17.8%/18.7%/17.1% mean weight loss respectively (placebo −0.1%). In the combined treatment groups, the proportions achieving 5%/10%/15%/20% weight loss were 98%/90%/65%/32% vs 13%/0%/0%/0% for placebo (p<0.01 each) (Viking press release).
The maintenance phase (weeks 21–33): Patients switched from weekly shots to every-other-week or once-monthly dosing for 12 weeks. Per BioPharma Dive: "average weight loss maintenance ranged from 82% to 97%, depending on the dosing strategy1... In the larger group of all enrollees moved to every-other-week dosing, average weight loss maintenance was 90%. For the monthly dosing group, that figure was 85%." The headline also flagged "22% Placebo-Adjusted Weight Loss Reported at Week 33 Following Weekly Dosing of VK2735 at 17.5 mg; No Plateau Observed." Discontinuations for side effects were rare (5 across all maintenance arms), and GI side effects weren't "meaningfully different" during maintenance.
Why it matters commercially. Adherence/persistence is the GLP-1 class's biggest commercial leak — Prime Therapeutics' year-two study (cited by Leerink) showed most patients abandon therapy early. Leerink analyst Thomas Smith called the data "stellar," writing that it "build[s] on [VK2735's] potentially differentiated profile" (BioPharma Dive). Obesity-society past president Dr. Louis Aronne (in Viking's statement): "These results are important as they provide a basis for improved dosing flexibility for both clinicians and their patients. Flexibility for patients and providers is paramount for achieving treatment persistence."
Caveats: n=180, healthy obesity only, 12-week maintenance window, and — critically — the Phase 3 program (fully enrolled as of November 2025) tests only up to 17.5 mg weekly, so the higher-dose signals (20/22.5 mg) won't inform the registrational dataset. Viking also initiated a Phase 1 of its amylin DACRA VK3019 and appointed Hubert Chen as CMO (StockTitan 8-K summary).
Meaning: Viking now owns the "dosing flexibility/maintenance" argument that Amgen's MariTide (monthly/quarterly, see Amgen Initiates MARITIME-SWITCH Phase 3 (Tirzepatide/Semaglutide → Monthly/Quarterly MariTide); T2D Phase 3s Still on Deck for 2026) and Lilly's orforglipron maintenance data have been circling — and the $500M raise funds the Phase 3 push plus the oral VK2735 program. The oral Phase 3 initiation (watched for by year-end, see Viking's VK2735 Maintenance Data Delivers: Up to 97% Weight-Loss Retention on Biweekly Dosing, No Plateau at Week 33 — Then a $500M Raise Cools the Stock) is the next binary.
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An instance of The metabolic battleground must now shift from peak weight loss to flexible maintenance protocols. — The headline differentiator being marketed is dosing flexibility and retention rather than peak weight loss. ↩︎