Efficacy of nivolumab/ipilimumab in patients with initial or late progression with nivolumab: Updated analysis of a tailored approach in advanced renal cell carcinoma (TITAN-RCC).
Authors: Grimm Marc-Oliver , Esteban Emilio , Barthélémy Philippe , Schmidinger Manuela , Busch Jonas , Valderrama Begoña P. , Schmitz Marc , Schumacher Ulrike , Baretton Gustavo Bruno , Duran Ignacio , de Velasco Guillermo , Priou Frank , Maroto-Rey Pablo , Schinzari Giovanni , Albiges Laurence 
Published: June 2021

4576 Background: TITAN-RCC uses a tailored immunotherapy approach in renal cell carcinoma (RCC), starting with nivolumab (nivo) induction followed by nivo + ipilimumab (ipi) as immunotherapeutic “boost” in non-responders. Patients with initial partial or complete response (PR/CR) continued with nivo maintenance but received later “boosts” for progressive disease (PD). Here we report updated results focusing on the efficacy of nivo+ipi in patients with initial PD vs. initial responders with later PD. Methods: Patients with IMDC intermediate and poor risk advanced clear cell RCC were recruited between OCT 2016 and DEC 2018. Patients started with nivo 240 mg Q2W induction. Patients with early significant PD (week 8) or non-responders at week 16 received 2-4 nivo+ipi “boost” cycles. Responders (PR/CR) to nivo monotherapy continued with maintenance but could receive nivo+ipi for later PD. The primary endpoint is confirmed investigator assessed objective response rate (ORR) per RECIST in first line (1L) and second line (2L). Secondary endpoints included activity of nivo monotherapy, remission rate with nivo+ipi “boost”, safety and overall survival (OS). Results: 109 1L and 98 2L (after TKI) patients were analyzed for efficacy. Median age was 65 years (range 20-87). 71 % were intermediate and 25 % poor risk. Confirmed ORR with nivo monotherapy was 28 % for 1L and 17 % for 2L. After a median follow-up of 12.8 months best overall response after nivo induction ± nivo+ipi was 36 % in 1L and 30 % in 2L. Of all patients, 38 received nivo+ipi for stable disease (SD) up to week 16, with 1 (3 %), 4 (11 %) and 26 (68 %) achieving CR, PR and SD, respectively. 28 patients in 1L and 43 in 2L were boosted with nivo+ipi for initial PD. Of these, 3 (11 %) and 8 (29 %) achieved PR and SD, respectively, in 1L, whereas 3 (7.0 %) achieved CR, 6 (14 %) PR and 13 (30 %) SD in 2L. 16 and 10 patients received “boosts” later than week 16 for PD during nivo maintenance in 1L and 2L, respectively. Thereof, 3 (19 %) achieved PR and 5 (31 %) SD in 1L, whereas 2 (20 %) achieved PR and 3 (30 %) SD in 2L. Progression-free survival was 6.3 months (95 % CI 3.7 – 10.1) and 3.7 months (95 % CI 2.0 - 4.5) in 1L and 2L, respectively. OS was 27.2 months (95 % CI 19.9 – not estimable (NE)) in 1L and 20.2 months (95 % CI 15.6 – NE) in 2L. Treatment-related adverse events will be presented. Conclusions: Our tailored approach with nivo+ipi “boosts” results in improved response rates compared to nivo monotherapy. Our updated analysis suggests that almost half of the patients receiving “boosts” for PD improve to either PR/CR (18 %) or SD (30 %), irrespective of initial or later progression with nivo. Clinical trial information: NCT02917772. [Table: see text]