Anti-PD-1 antibody in combination with radiotherapy as first-line therapy for unresectable intrahepatic cholangiocarcinoma

Abstract Background Unresectable intrahepatic cholangiocarcinoma (iCCA) has a poor prognosis despite treatment with standard combination chemotherapy. We aimed to evaluate the efficacy and safety of radiotherapy in combination with an anti-PD-1 antibody in unresectable iCCA without distant metastases. Methods In this phase II study, patients with histopathologically confirmed unresectable primary or postoperative recurrent iCCA without distant metastases were enrolled. Patients received external radiotherapy with a dose of ≥45 Gy (2-2.5 Gy per fraction), followed by anti-PD-1 immunotherapy (camrelizumab 200 mg once, every 3 weeks) initiated within 7 days after completion of radiotherapy as first-line therapy. The primary endpoint was 1-year progression-free survival (PFS) rate. The secondary end points included safety, objective response rate (ORR), disease control rate (DCR), and overall survival (OS). Results From December 2019 to March 2021, 36 patients completed radiotherapy and at least one cycle of immunotherapy and were included in efficacy and safety analyses. The median follow-up was 19.0 months (IQR 12.0-24.0), and the one-year PFS rate was 44.4% (95% CI, 30.8-64.0). The median PFS was 12.0 months (95% CI, 7.5-not estimable); the median OS was 22.0 months (95% CI, 15.0-not estimable). The ORR was 61.1% and the DCR was 86.1%. Seventeen of 36 (47.2%) patients experienced treatment-related adverse effects (AEs) of any grade. The most common AE was reactive cutaneous capillary endothelial proliferation (25.0%). Five (13.9%) patients experienced grade ≥3 treatment-related AEs, including decreased lymphocyte (5.6%), bullous dermatitis (2.8%), decreased platelet count (2.8%), and deep-vein thrombosis (2.8%). Conclusions External radiotherapy plus camrelizumab, as first-line therapy, met its primary endpoint and showed antitumor activity and low toxicity levels in patients with unresectable iCCA without distant metastases, warranting further investigation. Trial registration NCT03898895. Registered 2 April 2019.