• Viking is testing whether VK2735 can shift patients from weekly weight-loss injections to monthly maintenance dosing.
• The completed study tested every-other-week doses up to 10 mg and monthly doses reaching 22.5 mg; results remain due this quarter.
• Viking considers 75% retention of patients’ initial weight loss a decent maintenance benchmark.

Viking Therapeutics (VKTX) is looking to challenge Big Pharma’s obesity leaders with a potentially strong differentiator: a treatment that could move patients from weekly injections during active weight loss to just one shot a month for long-term maintenance.

But CEO Brian Lian said monthly VK2735 must clear a crucial test beyond keeping weight off: patients need to tolerate the larger, less-frequent doses without nausea, vomiting, and other gastrointestinal side effects returning. “Because if you maintain but everybody vomits, no one is going to want to take the drug,” Lian said at Morgan Stanley’s 24th Annual Global Healthcare Conference. 

Viking has completed the maintenance study and reaffirmed that results are expected this quarter. VKTX stock fell over 1% on Monday, logging its fifth straight session in the red. 

Viking Tests A Monthly Future For VK2735

VK2735 is a dual GLP-1/GIP receptor agonist in the same class as Lilly’s Tirzepatide. Its nine-day half-life could allow patients to receive fewer injections after reaching their target weight. “We thought, well, maybe you can dose once a month,” Lian said. “The PK from the Phase 2 indicated, yeah, maybe that is possible.”

Participants received weekly VK2735 before transitioning at week 21 to every-other-week or monthly dosing through week 33. Viking tested 5-mg, 7.5-mg and 10-mg doses every other week, with monthly doses reaching 22.5 mg. Another arm remained on 17.5 mg weekly.

Could Monthly Dosing Restart GLP-1 Side Effects? 

GLP-1-related nausea, vomiting, constipation and diarrhea typically emerge early and ease over time. The unanswered question is whether waiting a month between large doses effectively restarts that cycle. “If you don't take a dose for a month and then you take that high dose, are you going to trigger all the same GI adverse events?” Lian said. “I can see it either way.”

Drug levels could fall enough over 30 days for the next injection to cause a sharp exposure increase. Alternatively, VK2735’s long half-life could maintain meaningful levels throughout the month. “Which of those wins, I don't know,” Lian said.

This makes tolerability potentially more important than the headline maintenance result. “If you can show decent tolerability through the maintenance period, it's really important, I'd say almost more important than the maintenance effect,” he said.

The Key Numbers Viking Wants From VK2735 

Lian said retaining at least 75% of patients’ initial weight loss may preserve the cardiometabolic benefits achieved during weekly treatment. “If we can, after 12 weeks, keep people within 75% of the weight loss that they had achieved at week 21, I think that would be of interest,” he said.

Viking will also watch whether patients remaining on 17.5 mg weekly continue losing weight without reaching a plateau. “Regardless of the magnitude at week 33, what does the slope look like?” Lian said. “Is the slope continuing negative without evidence of a plateau?”

VK2735 previously produced 14.7% mean weight loss after 13 weeks at 15 mg. Viking hopes the longer 17.5-mg arm will exceed that result, but Lian cautioned that it includes only 15 patients. “Hard to know how that's going to predict a 4,000-patient study,” he said.

Viking Takes On Lilly, Novo And Pfizer 

Promising maintenance regimens could enter a 52-week extension of Viking’s Phase 3 Vanquish program. “We would like to, if we see interesting data in the maintenance study, bring one, two, three arms into that extension study,” Lian said.

Vanquish-1 and Vanquish-2 are fully enrolled, with results expected in the second half of 2027. Viking also plans to start two Phase 3 trials of oral VK2735 in the fourth quarter, giving it weekly, monthly and pill-based possibilities around the same molecule.

The competition is intensifying. Lilly and Novo dominate the obesity market, while Pfizer entered through its $10 billion Metsera acquisition and is separately pursuing a monthly injection.

Still, Viking says it does not need to match Big Pharma’s scale. “We don't need 40% market share to be successful,” Lian said. “We can have a much smaller portion of the market and really have a successful franchise.”

How Do Retail Traders Feel About VKTX?

On Stocktwits, retail sentiment for VKTX jumped to ‘bullish’ from ‘neutral’ levels a week ago amid an 819% surge in 24-hour message volumes.

One user said, “Classic BL, under promise & overdeliver. But I'll say it. Manifest it really. Vk2735 SC 17.5mg is definitely gonna hit 15% WL. Maybe even knock it out of the park at 18% WL.”

Another user said, “$VKTX Been saying for 2yrs since '25 that NVO should BO VKTX with minimum $15B+ BO bid or at the very least partner VK2735 rn in the EU/ROW.”

VKTX stock has risen 27% over the past year. 

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