Novo's Triple Threat Obesity Drug Just Entered the Ring

Novo has been playing defense for months. In late February, CagriSema posted 23% mean weight loss over 84 weeks in the primary analysis of its Phase 3 trial, which sounds impressive until you learn that Lilly's Zepbound hit 25.5% in the same head-to-head study. CagriSema didn't just lose; it failed the statistical test for non-inferiority, meaning it couldn't even prove it was "close enough."

That stung. Analysts started questioning whether Novo could compete in the next generation of obesity drugs. Lilly's stock surged. Novo's looked shaky.

UBT251 changes the conversation. Losing nearly 20% of body weight in 24 weeks is a blazing pace. CagriSema took 84 weeks to reach a similar number. Of course, cross-trial comparisons are notoriously unreliable (different patients, different designs, different everything), but the trajectory caught people's attention.

Martin Holst Lange, Novo's chief scientific officer, highlighted UBT251's "differentiated clinical profile and safety and tolerability profile." Translation: this drug doesn't just work differently; it seems to work well and patients can tolerate it.

The Lilly Problem Isn't Going Away

Before Novo pops any champagne, there's a heavyweight in the other corner. Lilly's own triple agonist, retatrutide, has shown up to 28.7% weight loss in trials. That's a staggering number, potentially rivaling what bariatric surgery achieves. One Wall Street analyst described retatrutide's data as "raising the bar" for the entire field.

Lilly also has tirzepatide already dominating the market. The tirzepatide franchise — combining Mounjaro and Zepbound sales — became the world's best-selling drug in 2025, surpassing even Merck's blockbuster cancer drug Keytruda. And Lilly is pushing an oral version, orforglipron, toward expected FDA approval in 2026.

Novo isn't out of ammunition, though. Oral Wegovy was approved in December 2025, and a higher-dose injectable version (7.2 mg, with 18.7% weight loss over 72 weeks) awaits an FDA decision in early-to-mid 2026. The company's pipeline is deep; it's just a question of whether any of these drugs can match Lilly's efficacy numbers.

What Happens Next

UBT251's Phase 2 trial was conducted in Chinese patients, and United Laboratories plans to move into Phase 3 in China. Meanwhile, Novo has its own global Phase 1b/2a trial running with about 330 patients, with topline results expected in 2027. A separate Phase 2 trial in type 2 diabetes is planned for the second half of 2026.

The detailed Phase 2 data will be presented at a medical congress later this year. That presentation will matter enormously, because the headline numbers only tell part of the story. Investors and clinicians will want to see dose-response curves, dropout rates, and how the gastrointestinal side effects compare to existing drugs at equivalent weight loss levels.

Meanwhile, in Oncology: A $1.7 Billion Handshake

While obesity grabbed the spotlight, another deal worth watching landed the same week. Astellas and Vir Biotechnology struck a partnership worth up to $1.7 billion to develop VIR-5500, a T-cell engager targeting PSMA in prostate cancer.

Vir gets $335 million upfront (including $240 million in cash and a $75 million equity investment at a 50% premium), plus up to $1.37 billion in milestones and double-digit royalties on sales outside the U.S.

The early clinical data explains why Astellas wrote such a big check: 82% of patients saw their PSA levels cut in half, and 53% experienced a 90% or greater reduction. VIR-5500 uses something called "dual-masking" technology, which keeps the drug inactive until it reaches the tumor. Think of it like a grenade with two safety pins; it won't go off until it's exactly where it needs to be.

Vir expects to start Phase 3 in 2027, with dose-expansion cohorts in earlier-stage prostate cancer launching in Q2 2026.

The Bottom Line

Novo's Triple G data is genuinely exciting, but it's also genuinely early. Phase 2 in 205 patients is a proof of concept, not a finish line. The real test comes when UBT251 faces larger, longer, more diverse trials, and eventually, a direct comparison to whatever Lilly brings to the table.

The obesity drug war is entering its most intense phase yet. Novo just proved it has a credible next-generation contender. Whether that's enough to close the gap with Lilly is the multibillion-dollar question that won't be answered until 2027 at the earliest. For now, the scoreboard reads: advantage Lilly, but the game's not over.