Pivotal single-arm, phase 2 trial of tasurgratinib for patients with fibroblast growth factor receptor (FGFR)-2 gene fusion-positive cholangiocarcinoma (CCA).

Abstract

471 Background: CCA represents ~3% of all gastrointestinal malignancies globally; it is particularly prevalent in Asian countries. Additionally, FGFR2 gene fusions occur in ~13% of intrahepatic CCA cases. Tasurgratinib (E7090) is an orally available selective inhibitor of FGFR 1–3; the recommended dose is 140 mg per day per the dose-escalation part of a first-in-human phase 1 study. In this pivotal phase 2 study, this regimen was evaluated in patients (pts) with FGFR2 fusion-positive CCA. Methods: Japanese and Chinese pts with surgically unresectable advanced or metastatic CCA were treated with tasurgratinib 140 mg PO daily. FGFR2 gene fusion was confirmed by fluorescence in situ hybridization performed in central laboratories; ≥ 1 prior chemotherapy regimen including a gemcitabine-based combination was required; pts treated with FGFR2 inhibitors were excluded. The primary endpoint was objective response rate (ORR; complete response [CR] + partial response [PR]). Secondary endpoints included duration of response (DOR), time to response (TTR), disease control rate (DCR; CR + PR + stable disease [SD]), clinical benefit rate (CBR; CR + PR + SD lasting ≥ 23 weeks), progression-free survival (PFS), overall survival (OS), and safety. The study was considered successful if the lower limit of the ORR 90% CI was > 15% in a planned population. Tumor responses were measured every 8 weeks by RECIST v1.1 per independent imaging review. Adverse event (AE) severity was measured per CTCAE v4.03. Results: 63 Pts (Japanese: n = 28; Chinese: n = 35) were treated (median age: 55 years); 23 pts (37%) had received 1 prior regimen, all others had received ≥ 2. By the data cutoff date (March 15, 2023), 55 pts discontinued treatment (disease progression, n = 48; adverse events, n = 4; pt choice, n = 2; loss of clinical benefit, n = 1). 19 Pts (30%) had a PR; 31 pts (49%) had SD and 13 (21%) had SD for ≥ 23 weeks. The ORR was 30% (2-sided 90% CI 20.7–41.0; 95% CI 19.2–43.0); the DCR was 79% (95% CI 67.3–88.5); the CBR was 51% (95% CI 37.9–63.6). The median [m]TTR / DOR for responders were 1.87 mos (IQR 1.77–2.10; range 1.6–14.7) / 5.6 mos (95% CI 3.7–9.3; range 1.0+–14.8+). The mPFS / OS were 5.4 mos (95% CI 3.7–5.6) / 13.1 mos (95% CI 10.8–17.4). 61 Pts (97%) had ≥ 1 treatment-related AE (TRAE), most commonly hyperphosphatemia (n = 51; 81%); 18 pts (29%) had ≥ 1 grade ≥ 3 TRAE, most commonly lipase increased (n = 4; 6%). 34 Pts (54%) had a dose reduction and 18 (29%) had treatment interruption due to TRAEs. 4 Pts (6%) had a fatal AE, none related to treatment. Conclusions: Tasurgratinib had promising antitumor activity in pts with CCA harboring FGFR2 gene fusion and who received ≥ 1 prior chemotherapy regimen. The primary endpoint (ORR) met the study’s predefined success criteria. Tasurgratinib had a manageable safety profile consistent with previous reports and with the known pharmacological profile of FGFR inhibitors. Clinical trial information: NCT04238715 .