PROOF 302 is an ongoing randomized, double-blind, placebo-controlled, adjuvant phase III trial (NCT04197986) in approximately 218 patients from 120 centers worldwide. Eligibility criteria include post-surgical high-risk muscle-invasive upper tract urothelial cancer (85% of patients) or urothelial bladder cancer (15%), susceptible FGFR3 alterations (activating mutations, gene fusions or rearrangements), ≤120 days following radical surgery and ineligible for/or refusing cisplatin-based (neo)adjuvant chemotherapy. Patients receive either oral infigratinib 125 mg or placebo daily on days 1-21 of a 28-day cycle for up to 52 weeks or until recurrence, unacceptable toxicity or death. Primary end point: centrally determined disease-free survival (DFS); secondary end points: investigator-assessed DFS, metastasis-free survival, overall survival and safety/tolerability; exploratory end points: correlative biomarker analysis, quality-of-life and infigratinib pharmacokinetics.
Keywords: FGFR inhibitor; FGFR3; PROOF 302; adjuvant cisplatin-based chemotherapy; adjuvant therapy; cisplatin-therapy refusal; fusions or rearrangements; infigratinib; muscle-invasive urothelial carcinoma; mutations; neoadjuvant cisplatin-based chemotherapy; phase III; upper tract urothelial carcinoma; urothelial bladder carcinoma; urothelial carcinoma.
Cancers of the bladder and other parts in the urinary system, especially those that are invasive and grow into the muscle layer, may need extra treatment after surgical removal of the tumor, particularly if there is a high risk of the cancer coming back. Chemotherapy regimens that include cisplatin are often used postoperatively, although some patients are unable to tolerate this treatment or refuse it. FGFR3, a protein that is encoded by the FGFR3 gene, is often changed in these cancers. This helps the tumor grow. Infigratinib is an investigational drug that targets FGFR3 and inhibits the abnormal growth of the tumor. In the PROOF 302 study, patients are randomly assigned to treatment with infigratinib or a placebo pill for 1 year after surgery to see if the drug is effective. The aim is to see if patients who take infigratinib have a longer time free from the disease than those who receive a placebo. The study will also look at how long patients remain free from cancer spread and how long they live overall. The study will also investigate how safe the treatment is and how easy it is to live with it. PROOF 302 is an important study as it will define the role of infigratinib in patients with cancers of the bladder and urinary system who also have FGFR3 changes, for whom more treatment choices are needed. Clinical Trial Registration: NCT04197986 (ClinicalTrials.gov).