FX-909 Shows Biomarker-Driven Activity in Advanced Urothelial Cancer
Key Clinical Summary:
- Design/Population: Phase 1A dose-escalation study of FX-909, a first-in-class oral PPARG inhibitor, in 46 heavily pretreated patients with advanced metastatic urothelial carcinoma, most of whom had received prior enfortumab vedotin and anti-PD-L1 therapy.
- Key Outcomes: Tumor regressions were observed in 18 of 26 patients with high PPARG expression (TPS ≥60%), including confirmed and unconfirmed partial responses. ctDNA reductions were seen in the majority of evaluable PPARG-high patients, supporting biologic activity.
- Clinical Relevance: These findings provide clinical proof-of-concept for targeting PPARG, a master regulator of luminal lineage, and support biomarker-driven development of FX-909 in PPARG-high urothelial carcinoma, with randomized expansion and combination studies underway.
Matthew Galsky, MD, Mount Sinai Medical Center, New York, New York, discusses results from a phase 1 study evaluating FX-909, a first-in-class PPARG inverse agonist, in patients with advanced urothelial cancer.
Results demonstrated that FX-909 shows preliminary antitumor activity, particularly in tumors with high PPARG expression, and support continued clinical development of this novel targeted approach in luminal urothelial cancers.
Dr Galsky presented these results at the 2026 American Society of Clinical Oncology (ASCO) Genitourinary Cancers Symposium in San Francisco, California.
Source:
Galsky MD, Bellmunt J, Mantia C, et al. Updated clinical results and associated biomarkers from an ongoing phase 1 study of FX-909, a first-in-class peroxisome proliferator-activated receptor gamma (PPARG) inhibitor, in patients (pts) with advanced urothelial carcinoma (adv UC). Presented at ASCO GU. February 26 - 28, 2026. San Francisco, California. LBA639.
