AbstractBackgroundFIGHT‐102 was a phase 1, dose‐escalation, dose‐expansion study of pemigatinib in Japanese patients with advanced solid tumors. Here, we report safety, tolerability, and preliminary efficacy of pemigatinib from FIGHT‐102.MethodsPatients (≥20 years old) self‐administered oral pemigatinib 9, 13.5, or 18 mg QD on intermittent dosing (Part 1) or 13.5 mg QD intermittent or continuous dosing (Part 2). A dosing cycle was 21 days (2 weeks on/1 week off or 21 continuous days). Primary endpoint was safety. Secondary endpoints were pharmacokinetics, pharmacodynamics, and preliminary efficacy.ResultsForty‐four patients (Part 1,n= 14; Part 2,n= 30) were enrolled; most common tumors, cholangiocarcinoma,n= 8; esophageal,n= 6; 26 patients had confirmedFGF/FGFRalterations (Part 1,n= 3; Part 2,n= 23); 70.5% had ≥3 prior systemic therapies. Maximum tolerated dose was not identified. The recommended phase 2 dosage was determined to be 13.5 mg QD. Most common treatment‐emergent adverse events (TEAEs) were hyperphosphatemia (81.8%), dysgeusia (45.5%), stomatitis (43.2%), and alopecia (38.6%); most frequent Grade ≥3 TEAEs were anemia and decreased appetite (9.1% each). In Part 1, no patient achieved partial response (PR) or complete response, and 7 (50.0%) patients had stable disease (SD). In Part 2, 5 (16.7%) patients achieved PR (one each with cholangiocarcinoma, gall bladder cancer, breast cancer, urothelial tract/bladder cancer, and sweat gland carcinoma) and 6 (20%) had SD. Median duration of response was 9.56 months (95% CI: 4.17, 14.95).ConclusionsPemigatinib demonstrated manageable adverse events, consistent pharmacokinetics and pharmacodynamics profiles, and preliminary efficacy in Japanese patients with advanced solid tumors.