Viking Therapeutics (VKTX) Delivers Great VK2735 Results: Here's a Word of Caution

The recent maintenance trial results from Viking Therapeutics (NASDAQ: VKTX) led to a surge in the share price. In its aftermath, management announced a $275 million common stock offering and $225 million in convertible senior notes to support the development of its drug pipeline. The trial results are exciting and further support management's VK2735 program, but investors should note that the trial did not include VK2735 in oral form, so there's still a question mark around it.

Viking Therapeutics maintenance trial results

VK2735 is a GLP-1 and GIP agonist in development to treat obesity and patients with obesity and type 2 diabetes. Following favorable Phase 2 data, it's already in Phase 3 trials in subcutaneous (injectable) form, and management expects to start Phase 3 trials for VK2735 in oral form this year.

Viking's drug candidate has two key advantages that could enable it to build a profitable niche in the highly competitive weight-loss treatment market, currently dominated by Eli Lilly and Novo Nordisk. Specifically, the Phase 2 (subcutaneous) data suggest that VK2735 generates rapid weight loss compared with peers. In addition, VK2735 is being developed as a dual formulation, in which an initial rapid weight-loss dose in subcutaneous form can be followed by more convenient oral VK2735 dosing.

The market was excited by the recent maintenance trial results, which showed some very impressive weight loss results in the initial stage (patients on the initial weekly 21-week 17.5 mg dose had a 17.8% reduction in weight) and also in the maintenance phase (patients shifting to the biweekly 12-week 17 mg dose maintained 97% of the weight loss generated at the 21-week stage).

Those are impressive results. But here's the thing: These results pertain only to subcutaneous dosing, not to the oral formulation.

An oral maintenance study is coming

The oral VK2735 maintenance dose is arguably more important, as it differentiates the drug and would encourage patients to take VK2735 subcutaneously, knowing they could seamlessly switch to an oral formulation to maintain weight loss.

However, doubts were cast on the potential of the dual formulation strategy after the release of disappointing safety and tolerability data from the Phase 2 VK2735 oral trial (Venture-Oral) in August 2025. For example, in the Venture-Oral trial, 20% of treated patients withdrew due to an adverse event (primarily gastrointestinal).

That said, the Phase 2 trial was relatively short, at just 13 weeks, and may have involved an overly aggressive titration. Clearly, there's an opportunity to design the Phase 3 trial with the tolerability data from Phase 2 in mind. Indeed, CEO Brian Lian told investors at a Morgan Stanley conference (courtesy of S&P Global Market Intelligence) that they would come "down a little bit in dose in the Phase 3 study," and be "reducing the tablet size, reducing the tablet count and really kind of on the middle of that dose response curve from the Phase II, which had gone up to 120 mg."

In addition, Viking Therapeutics investors will get a read, although not a definitive one, on VK2735 oral in the second part of the maintenance trial, which management said will begin imminently. Lian said the oral doses in the maintenance study would be 17.5 mg, 27.5 mg, and 35 mg. Based on the Phase 2 weight-loss trial, these appear to be relatively low doses, which could improve tolerability as maintenance doses.

Where next for Viking Therapeutics?

The maintenance trial update is good news, and the capital raise was well-received. Still, investors need to be mindful that the oral data from the second part of the maintenance trial is also extremely important for the stock and its potential as a dual-formulation strategy.

Lee Samaha has no position in any of the stocks mentioned. The Motley Fool has positions in and recommends Eli Lilly and Novo Nordisk. The Motley Fool recommends Viking Therapeutics. The Motley Fool has a disclosure policy.