215P - Analysis of spatial heterogeneity of responses in metastatic sites with nivolumab in renal cell carcinoma

Background

The study was done to appraise whether tumor response to CPI in RCC varies among organs and describe the response patterns in a population of surgically treated metastatic RCC patients treated with Nivolumab.

Methods

A retrospective analysis was conducted in patients receiving Nivolumab for metastatic RCC after first-line therapy, between January 2016 and March 2020, having at least a baseline and two follow up scans. Comparison across groups was performed using a Fisher exact test for categorical variables and a Kruskal-Wallis test for continuous variables. TTP was estimated using a Kaplan-Meier method.

Results

21 out of 30 patients analyzed were eligible and were classified into two arms as either responder ( n=11) or non-responders ( n=10). Of the 21 patients, 18 (85.7 %) had the following: PD (10 patient), PR (3 patients) and SD (8 patients) according to all iRECIST guidelines. Overall, 7, 15, 4, 13, 7, and 7 patients had measurable hepatic metastasis and lung, brain, lymph node, soft tissue and other intra-abdominal metastases at baseline, respectively; these patients were subject to organ-specific response evaluation. Organ-specific ORRs of hepatic metastasis and lung, brain, lymph node, soft tissue, adrenals and other intra-peritoneal metastases were 10, 19, 20, 35, 0, 25 and 25%, respectively. Among them, 13 (61.9%) exhibited differential responses to CPI treatment with 6 (28.5 %) patients revealing intra – organ differential response. The best objective response (BOR) was seen in lymph nodes (35%), followed by adrenals and peritoneal (25 % both) followed by the brain (20%) and lung (19%). The response rate was highest in adrenal gland lesions (2/4; 50%) followed by lymph nodes (13/19; 68.4 %) and liver ( 5/10; 50 %), while the rates were intermediate in lung (9/25; 36 %), intraperitoneal metastasis ( 1/4; 25%), brain (1/5; 20 %), and lowest in soft tissue (1/7; 14.2 %) lesions.

Conclusions

There is a differential response to checkpoint inhibitors at different metastatic sites in Renal Cell carcinoma, With highest Best response in Lymph nodes and least in soft tissue.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Rajiv Gandhi Cancer Institute and Research Center.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.