960PNivolumab (N) treatment beyond progression in a real-world cohort of patients (pts) with metastatic renal cell carcinoma (mRCC)

Abstract Background N is a standard of care for patients with mccRCC after failure of a TKI. Nevertheless, nearly 45% of pts had a progressive disease (PD) as best response and PFS was disappointing. In this study we sought to describe a “real-world” cohort of pts with mRCC treated with N beyond first progression to identify factors predicting a clinical benefit. Methods We included in a retrospective study all consecutive mRCC pts who received at least one N injection at a French single-center between 2013 and 2018. Clinical and biological data were collected prospectively. Radiological evaluations were done by CT-scan using iRECIST. Characteristics of pts who with unconfirmed PD (iuPD) were described and compared according to the continuation of N beyond iuPD or not. Pts with a clinical benefit (CB) (objective response (OR=CR+PR) or stable disease (SD)) from N post-iuPD, were compared with pts with icPD as best response (BOR) post-iuPD. Results 109 patients were included, 84% had a clear cell histology; IMDC’s favorable, intermediate and poor prognostic groups at N initiation were 21%, 52% and 27%, respectively. After a median follow-up of 24.4 months [14.9-NA], median PFS and OS were 6.03 months [4.6-10] and 25.8 months [24.2-30.1] respectively. ORR was 18.4% (3.7% CR) and 74 pts experienced a first iuPD, including 5 clinical PD. Among the 69 radiological iUPD, 12 had new lesions (16%), 32 had progression of pre-existing lesions (43%) and 25 had both (33%). 36 pts (49%) received N beyond PD. Responses post-iuPD were 3 (4%) PR, 14 (19%) SD and 17 (23%) icPD.; they were more frequently ECOG-PS 0-1 (86% versus 47%, p = 0.0005), had better IMDC group (FAV+INT = 86% vs 53%, p = 0.01) and had higher lymphocyte count (p = 0.04). 17/18 (48%) pts had a CB with N post-iuPD, with a better OS than those without CB (31.8 months vs 24.9 months, p = 0.02). The only factor associated with the absence of CB were LDH>200 (p = 0.038). Conclusions We report the largest analysis of treatment with N beyond progression in a real world cohort of mRCC supporting that pseudo-progression is a rare event (4%). We show also that treatment beyond progression is very common (49%) and that LDH>200 might be the better ready-to-use predictive factor of a lack of CB. Legal entity responsible for the study Yann-Alexandre Vano. Funding Has not received any funding. Disclosure L. Fournier: Speaker Bureau / Expert testimony: Bayer; Speaker Bureau / Expert testimony: Novartis; Speaker Bureau / Expert testimony: Janssen; Speaker Bureau / Expert testimony: Sanofi; Research grant / Funding (institution): Invectys; Research grant / Funding (institution): Philips; Research grant / Funding (institution): Evolucare; Research grant / Funding (institution): ArianaPharma; Research grant / Funding (institution): Imagia. C. Thibault: Advisory / Consultancy, Research grant / Funding (institution), Travel / Accommodation / Expenses: AstraZeneca; Advisory / Consultancy: BMS; Travel / Accommodation / Expenses: Roche; Advisory / Consultancy, Research grant / Funding (institution), Travel / Accommodation / Expenses: Sanofi; Advisory / Consultancy, Travel / Accommodation / Expenses: Janssen; Advisory / Consultancy: Astellas; Advisory / Consultancy, Travel / Accommodation / Expenses: Pfizer. Y. Vano: Advisory / Consultancy, Research grant / Funding (institution): BMS; Advisory / Consultancy: Roche; Advisory / Consultancy: Ipsen; Advisory / Consultancy: Pfizer MSD; Advisory / Consultancy: Novartis; Advisory / Consultancy: Merck; Advisory / Consultancy: Janssen-Cilag; Advisory / Consultancy: Sanofi; Advisory / Consultancy: Astellas. All other authors have declared no conflicts of interest.