The biotech's stock is having its best day in more than two years on a data point that says more about durability than about how much weight patients lost in the first place.
Viking Therapeutics shares surged more than 25% Tuesday, putting the stock on pace for its biggest one-day gain since February 2024, after the company reported new data suggesting patients on its experimental obesity treatment can maintain most of their weight loss even after cutting back on how often they take it.
In the study, patients who switched from weekly to every-other-week dosing of VK2735 kept off an average of 90% of the weight they had initially lost. Those who moved to a once-monthly maintenance dose retained an average of 85% of their loss, compared with roughly 61% retention in a placebo group over the same period. Citi analyst Geoff Meacham called the finding notable less for the headline weight-loss number than for what it implies about long-term use: "The efficacy is impressive, though preserving these reductions with fewer injections provides the more differentiated finding."
The result builds on earlier data showing patients lost between 16% and 19% of their body weight after 21 weeks on VK2735, putting it in the same range as rival treatments from Eli Lilly and Novo Nordisk. VK2735 targets the same hormone receptors as Lilly's Zepbound and Mounjaro and is administered as a once-weekly injection, with an oral version also in development.
The maintenance-dosing angle matters commercially because it speaks directly to one of the biggest open questions in the obesity-drug market: whether patients can eventually step down to less frequent, less burdensome dosing without losing the benefit, a factor that could shape both pricing and long-term adherence across the entire drug class. Shares of Eli Lilly and Novo Nordisk, the two companies whose market lead Viking is chasing, each slipped modestly on the day, a sign investors are treating Viking's data as a genuine, if still early-stage, competitive threat rather than background noise.