The stakes are getting even higher for the fight between Eli Lilly and Novo Nordisk for supremacy in the multibillion-dollar obesity market.

Lilly on Friday quietly registered a new phase 3b trial on clinicaltrials.gov. The study, coded SURMOUNT-5, will pit Lilly’s Mounjaro against Novo’s Wegovy in patients with obesity or overweight with weight-related health conditions.

The trial aims to enroll 700 participants from 61 sites in the U.S., Canada, South America and several European countries, according to the post. The study is currently expected to officially start next Friday and last for about 78 weeks, with an estimated primary completion date in February 2025.

On the study’s primary endpoint, investigators will compare the percentage weight changes between the two drugs by week 72 from baseline. However, it’s not immediately clear whether Lilly is designing SURMOUNT-5 as a superiority study to show Mounjaro is better than Wegovy or just to show noninferiority. Other secondary measurements include the percentage of patients who’ve achieved certain magnitude of weight loss.

Lilly didn’t immediately respond to a Fierce Pharma request for comment by publication time.

The new study comes as both drugs gained much fanfare with the help of anecdotal adoption by Hollywood stars, an unexpected promotion by Twitter owner, Elon Musk, and viral spread on social media. Surging demand drove both drugs into months of shortage, which was just recently resolved.

The huge unmet need in weight management has spurred megablockbuster sales projections. Last fall, analysts at UBS projected that Mounjaro could reach a jaw-dropping $25 billion in peak sales with uses in both diabetes in obesity, although other more cautious analysts have put the potential at or below $10 billion.

In a report in November, Cowen analysts estimated that the global obesity drug sales could reach $30 billion by 2030, with Novo and Lilly leading the charge. An earlier Morgan Stanley research put the number at $50 billion.

Reference:https://www.fiercepharma.com/pharma/heavyweight-obesity-fight-lilly-launches-mounjaro-head-head-trial-against-novos-wegovy