AI-Discovered Drug Rentosertib Enters Phase III for Lung Fibrosis

Insilico Medicine has dosed the first patients in GENESIS-IPF-3, a Phase III trial testing rentosertib for idiopathic pulmonary fibrosis. The milestone marks the first time a drug discovered through generative AI has advanced to a randomized, double-blind, placebo-controlled Phase III study of this scale—320 patients across 47 sites in China, with treatment extending 52 weeks.

The trial's primary endpoint measures annual decline in forced vital capacity, a standard lung function metric that will determine whether Phase IIa signals translate to meaningful clinical benefit. According to details first reported by PR Newswire, Peking Union Medical College Hospital and Shanghai Pulmonary Hospital enrolled their first participants on the same day.

Why it matters

Rentosertib targets TNIK, a kinase with no established connection to fibrosis before Insilico's AI platform identified it. The two FDA-approved IPF drugs—pirfenidone and nintedanib, both cleared in October 2014—work through different mechanisms, leaving this pathway unexplored in approved therapies. If the Phase III data supports the dose-dependent efficacy trend published in Nature Medicine in 2025, rentosertib could offer the first new mechanism of action for IPF in over a decade.

Trial design and timeline

Lead investigator Professor Zuojun Xu estimates three to four years from Phase III initiation to potential approval under favorable conditions. With a 52-week treatment window, primary readout data is unlikely before late 2027. The FDA granted rentosertib Orphan Drug Designation in February 2023, though the drug remains investigational with no regulatory approval in any jurisdiction.

A 2026 Nature Biotechnology study reported consistent reductions in biological age markers across six independent aging clocks, providing secondary data that could support label expansion discussions if the primary endpoint succeeds. That evidence remains observational rather than interventional.

Financial position changes risk profile

Insilico reported $106 million in revenue for the first half of 2026, a 287% year-over-year increase, and posted its first profitable half-year since its December 2025 Hong Kong Stock Exchange listing. Adjusted net profit exceeded $51 million. The company has announced out-licensing and co-development deals totaling approximately $7.3 billion in contract value this year.

This financial structure differs from typical biotech Phase III economics. Funding a multi-year trial through licensing revenue rather than equity raises or debt changes the sustainability equation, particularly for a company that must maintain operations through a three-to-four-year development runway before potential approval.

What comes next

The 47-site Chinese enrollment will test whether Insilico's AI-driven target identification translates to clinical efficacy at scale. IPF affects approximately 100,000 people in the United States and has limited treatment options that slow but do not reverse disease progression. A successful Phase III would validate both the specific drug and the broader premise that generative AI can identify novel therapeutic targets in established disease areas.

Details of the trial initiation were first reported by PR Newswire.