Efficacy of first-line tyrosine kinase inhibitors plus immune checkpoint inhibitors in metastatic fumarate hydratase-deficient renal cell carcinoma / 中华泌尿外科杂志

ABSTRACT

Objective:To evaluate the efficacy of first-line tyrosine kinase inhibitors (TKI) plus immune checkpoint inhibitors (ICI) in metastatic fumarate hydratase-deficient renal cell carcinoma (FH-deficient RCC).Methods:The data of 87 metastatic FH-deficient RCC patients from West China Hospital ( n=44), Renji Hospital ( n=27) and Sun Yat-sen University Cancer Center (n=16) from Mar 2019 to Aug 2022 were retrospectively analyzed. The median age was 37(30, 47) years, the male to female ratio was 1.9∶1. The median size of tumor was 7.5(5.0, 10.0) cm. Sixty-one patients (70.1%) had germline FH mutations, and 26 patients (29.9%) had somatic FH mutations. Forty-nine patients (56.3%) metastasis disease at initial diagnosis, and 38 patients (43.7%) had metachronous metastasis. The most common site of metastasis was lymph node (41/87, 47.1%), followed by bone (33/87, 37.9%), liver (22/87, 25.3%), and lung (14/87, 16.1%). Fifteen patients (17.2%) had weak expression of FH protein and 59 patients (67.8%) had positive PD-L1 expression. The most common treatments were sintilimab plus axitinib (52/87, 59.8%), followed by pembrolizumab plus cabozantinib (7/87, 8.0%), tirelizumab plus axitinib (6/87, 6.9%), pembrolizumab plus axitinib (5/87, 5.7%), and toripalimab plus axitinib (4/87, 4.6%). Thirteen patients (13/87, 14.9%) received other ICI plus TKI combination treatments. Statistical analysis was conducted using R 4.2.3 software. Kaplan Meier survival curve was used to evaluate survival data, and log-rank test was used to compare differences between treatment groups. Results:The overall objective response rate (ORR) and disease control rate (DCR) of first-line TKI + ICI were 39.1% and 89.7%, respectively. The median progression-free survival (PFS) and overall survival (OS) were 16.5 months and 71.0 months, respectively. For first-line sintilimab plus axitinib, the ORR and DCR were 44.2% and 92.3%, respectively. The median PFS was 17.3 months and the median OS was not reached for this combination treatment. The efficacy of first-line tirelizumab plus axitinib was inferior to other treatment strategies (median PFS 4.0 vs. 16.6 months, P<0.001; median OS 22.0 vs. 71.0 months, P=0.043). Subgroup analyses further showed that the efficacy of ICI+ TKI combination therapy was consistent in patients with different clinicopathologic and genomic features. However, patients with liver metastasis had shorter OS than those without liver metastasis (median OS 26.3 vs. 71.0 months, P=0.021). Conclusion:First-line TKI + ICI is effective for metastatic FH-deficient RCC and can significantly prolong the survival of the patients.