Shares of Viking Therapeutics went vertical on Tuesday after the San Diego drugmaker released new trial data showing its experimental obesity treatment does something rival shots have struggled to prove: keep the weight off.

Viking Therapeutics (NASDAQ: VKTX) has spent the past two years as one of biotech's most-watched "GLP-1 pretenders" — a smaller player trying to carve out space in a market Novo Nordisk and Eli Lilly have used to become two of the most valuable healthcare companies on Earth. Tuesday's rally pushed the stock to its highest level in months.

The stock spiked as much as 39% intraday, according to trading data reported Tuesday, with other outlets clocking gains ranging from roughly 27% to 36% depending on the exact moment measured — the kind of single-day pop that turns an obscure mid-cap biotech into a Wall Street headline overnight.

What the Data Actually Showed

The trial focused on VK2735, Viking's dual GLP-1/GIP receptor agonist, in a maintenance study testing whether patients could hold onto weight they'd already lost. According to results detailed by GuruFocus, patients who'd initially lost weight on a weekly regimen for 21 weeks — shedding between 16% and 19% of their body weight, versus roughly 0% for those on placebo — kept off about 97% of that loss even when switched to less frequent dosing, with only mild side effects reported.

A DIRECT SHOT AT NOVO NORDISK AND ELI LILLY'S DOMINANCE

That durability question — whether patients regain weight once they cut back on injections — has dogged the entire GLP-1 category, dominated by Novo Nordisk's Wegovy and Eli Lilly's Zepbound. Analysts noted the data pressures both incumbents, since a drug that holds its effect with fewer doses could be both cheaper and more appealing to patients tired of weekly injections.

Viking says it now plans to push an oral version of VK2735 into Phase 3 trials by the end of 2026, a step that — if successful — could let the company skip the injection format altogether and compete for the pill-form obesity market that both Lilly and Novo are also racing to develop.

The move came the same day broader markets rallied, with the Nasdaq pushing toward its first record close since June on a renewed chipmaker rally, falling oil prices and a stronger-than-expected ADP employment report. But for weight-loss investors, Viking's single-stock surge was the story of the day — and rivals' shares will be watched closely for any reaction when markets open Wednesday.