RECIST 1.1 versus immune-related RECIST and immune-related response criteria in assessing response to nivolumab in patients with lung, renal, and head and neck cancers.

Abstract

e14609 Background: Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 is reported to underestimate response to immunotherapeutic drugs. Therefore, immune related RECIST (iRECIST) based on RECIST 1.1 and immune related response criteria (IRRC) based on WHO response criteria have been studied, mainly in patients with melanoma. Whether RECIST 1.1 underestimates responses in other cancers is not well known. Aim of the present study is to assess response rates to PDL-1 inhibitor Nivolumab in lung, renal and head and neck (H&N) cancers using RECIST 1.1, iRECIST and IRRC. Methods: We reviewed patients from 2012 to present with lung, renal, H&N cancers treated with Nivolumab at John h Stroger Jr. Hospital of Cook County. Incomplete charts and those treated for less than 4 cycles of Nivolumab were excluded. Data was analyzed using descriptive statistics and Fisher exact test. Results: 47 charts were reviewed, 27 met the inclusion criteria. 17 lung (14 adeno, 3 squamous), 7 renal (5 clear cell) and 3 H&N cancer patients were included. Average age was 58.2yrs, 20(74%) were male. Average treatment was for 13 cycles. Response was assessed after at least 4 cycles. Disease control rate for lung, renal, head and neck cancer was 70%,58%, 33% respectively with RECIST 1.1 criteria compared to 77%, 71% and 66% respectively using immune RECIST or IRRC (P > 0.05). No patient developed pseudoprogression. Two had progressive disease per RECIST 1.1 but stable disease with iRECIST and IRRC. 26 of the 27 patients showed concordance between iRECIST and IRRC. One patient had stable disease per iRECIST but partial response per IRRC. Average survival after treatment initiation was 8.3 months for lung, 9.1 months for renal and 5.6 months for H&N cancer. Treatment was discontinued in 2 patients based on progression per RECIST 1.1, both patients had stable disease per iRECIST& IRRC. Conclusions: Trend towards underestimation of treatment response using RECIST 1.1 criteria compared to iRECIST or IRRC was observed. Strong concordance was observed between iRECIST and IRRC. Given relative ease of use, iRECIST might be favored over IRRC in response evaluation for immunotherapeutic drugs.