Protagonist Therapeutics is taking aim directly at Eli Lilly's next-generation obesity treatment with a newly announced drug that uses the same mechanism.
Late Monday, Protagonist said it selected a drug it calls PN-477 to move into clinical testing. Like the experimental Eli Lilly drug, retatrutide, PN-477 mimics three hormone receptors — GLP-1, GIPR and GCGR — to curb hunger and improve blood sugar markers.
The company says its drug could be the best in the class. It has demonstrated "absolute and relative activity against all three hormone receptors in clinical testing," Protagonist Therapeutics Chief Executive Dinesh Patel said in a statement.
"PN-477 is specifically engineered to be orally stable with attention to the relative balance of potencies against the three receptors to potentially leverage their beneficial effects on weight loss and optimal body composition by mitigating their adverse effects," he said.
Protagonist stock is forming a cup-with-handle base with a buy point at 57.70, MarketSurge shows. The biotech stock has a strong IBD Digital Relative Strength Rating of 90. This means Protagonist Therapeutics stock ranks in the leading 10% of all stocks when it comes to 12-month performance.
Protagonist Therapeutics Takes On The Leaders
The two leading drugs in the obesity market are Novo Nordisk's Wegovy and Eli Lilly's Zepbound. Wegovy mimics the GLP-1 hormone, while Zepbound targets GLP-1 and GIPR. But there are no triple-targeting drugs on the market — yet.
"While GLP-1 agonists have dominated the market thus far, there remains a broad opportunity for novel therapeutics with better body weight loss, higher ratio of fat to lean mass loss, tolerability and additional beneficial effects in obesity-related comorbidities," Protagonist's Patel said.
Protagonist Therapeutics will begin testing PN-477 in people in the second quarter of 2026. The firm is looking at its obesity treatment as a daily pill or a weekly shot.
Obesity Market Is Getting Crowded
Both markets are getting plenty of attention these days. Wegovy and Zepbound are weekly shots. But a bevy of marquee names including Novo, Lilly, Roche, AstraZeneca, Pfizer and Merck are working on daily pills. Others, like Viking Therapeutics and Amgen, are taking a dual approach. Viking's VK2735 is similar to Zepbound. It mimics GLP-1 and GIPR. MariTide, from Amgen, mimics GLP-1 and blocks GIPR.
"A triple GLP-1, GIP, GCG receptor agonist peptide that offers weight loss on par with the best injectable treatments options, as well as the optionality provided by both oral and injectable routes of administration, would be an important therapeutic breakthrough and represents another potential blockbuster drug opportunity for Protagonist," Patel said.
But Protagonist Therapeutics is coming from far behind. According to ClinicalTrials.gov, Eli Lilly expects to wrap its Phase 3 study of retatrutide in obesity treatment in April 2026. Viking is currently running a study of its pill. That's expected to wrap up this August.
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