CAMBRIDGE, Mass. — August 5, 2025 — Leads & Copy — Flare Therapeutics Inc. (FlareTx) has dosed the first patients in its Phase 1B clinical trial evaluating FX-909, a first-in-class orally available small molecule inhibitor of PPARG, for treating locally-advanced or metastatic urothelial cancer (UC). The trial, identified as NCT05929235, is further detailed at clinicaltrials.gov.
The Phase 1B expansion study marks a milestone in improving the treatment of advanced urothelial cancer with FX-909, according to Doug Manion, M.D., FRCP (C), Chief Executive Officer and Board Member. The company is screening for patients with high PPARG expression, characteristic of the luminal lineage, which accounts for approximately 65% of advanced UC cases. The PPARG inhibitor approach in this patient population represents a step toward addressing the disease at its source, expanding the therapeutic landscape to directly target the cell of origin and address the underlying disease biology.
FX-909 has achieved clinical proof-of-concept in a Phase 1A study as a monotherapy, based on pre-specified criteria, with data presentation expected at a scientific conference in 2025. The Phase 1B study will evaluate safety and efficacy to determine the recommended Phase 2 dose in a biomarker-defined population, enrolling approximately 40 patients in total.
Efficacy data in a biomarker-defined population at the recommended Phase 2 dose is expected in the first quarter of 2026.
Advanced urothelial cancer (UC) is an aggressive form of bladder cancer, representing about 25% of all bladder cancers diagnosed each year. It is notably difficult to treat, with over 50% of patients experiencing disease progression within six to nine months of first-line chemotherapy. Luminal tumors, characterized by high PPARG expression, comprise approximately 65% of advanced urothelial cancers. Novel approaches such as PPARG inhibition are emerging as promising strategies to improve outcomes for patients that have UC with high PPARG expression. It is estimated that the United States alone, there are approximately 14,000 new cases of advanced urothelial cancer with high PPARG expression diagnosed each year, based on the portion of luminal subtypes and overall incidence data.
Flare Therapeutics is focused on drugging transcription factors. The company’s lead program, FX-909, is initially being developed for locally advanced or metastatic urothelial cancer. The second lead program, FX-111, is a novel and highly differentiated potent and selective degrader for ARON, with broad potential across prostate cancer at all stages. FX-111 is undergoing Investigational New Drug (IND)-enabling studies for initial development for the treatment of metastatic castration-resistant prostate cancer (mCRPC).
Contacts:
Sarah McCabe
investorrelations@flaretx.com
media@flaretx.com
Source: Flare Therapeutics Inc.
