The Clinical Activity of PD-1/PD-L1 Inhibitors in Metastatic Non-Clear Cell Renal Cell Carcinoma

Abstract

Programmed death 1 (PD-1) and PD ligand 1 (PD-L1) inhibitors have shown activity in metastatic clear cell renal cell carcinoma (ccRCC). Data on the activity of these agents in patients with non-clear cell RCC (nccRCC) or patients with sarcomatoid/rhabdoid differentiation are limited. In this multicenter analysis, we explored the efficacy of PD-1/PD-L1 inhibitors in patients with nccRCC or sarcomatoid/rhabdoid differentiation. Baseline and follow-up demographic, clinical, treatment, and radiographic data were collected. The primary endpoint was objective response rate. Secondary endpoints include time-to-treatment failure (TTF), overall survival (OS), and biomarker correlates. Forty-three patients were included: papillary (n = 14; 33%), chromophobe (n = 10; 23%), unclassified (n = 9; 21%), translocation (n = 3; 7%), and ccRCC with sarcomatoid differentiation (n = 7, 16%). Of those 43 patients, 11 patients (26%) had sarcomatoid and/or rhabdoid differentiation (n = 7 with ccRCC; n = 4 nccRCC). Overall, 8 patients (19%) objectively responded, including 4 patients (13%) who received PD-1/PD-L1 monotherapy. Responses were observed in patients with ccRCC with sarcomatoid and/or rhabdoid differentiation (n = 3/7, 43%), translocation RCC (n = 1/3, 33%), and papillary RCC (n = 4/14, 29%). The median TTF was 4.0 months [95% confidence interval (CI), 2.8-5.5] and median OS was 12.9 months (95% CI, 7.4-not reached). No specific genomic alteration was associated with clinical benefit. Modest antitumor activity for PD-1/PD-L1-blocking agents was observed in some patients with nccRCC. Further prospective studies are warranted to investigate the efficacy of PD-1/PD-L1 blockade in this heterogeneous patient population. Cancer Immunol Res; 6(7); 758-65. ©2018 AACR.

Figure 1.

Patient outcomes. Time-to-treatment failure (A) by histology and (B) by the IMDC risk group. Time-to treatment failure did not differ by histology. Time-to-treatment failure was more prolonged in favorable risk group patients. C, Swimmer plot of all patients stratified by histology and line of prior therapy. Each bar represents an individual patient. X, Time that treatment with PD-1/PD-L1 therapy was discontinued. ►, Patients who are still alive at the time of last follow-up.

Figure 2.

Genomic sequencing. Genomic mutations detected by deep-sequencing analysis from archival tumor specimens from 19 patients. Columns represent individual subjects. Rows represent selected genes of interest examined for each sample.