Real-world survival outcomes of patients (pts) treated with 6-weekly pembrolizumab 400mg (pem6w) plus axitinib (axi) for advanced renal cell carcinoma (aRCC).

645 Background: The Keynote 426 trial demonstrated 3-weekly pembrolizumab 200mg (pem3w) plus axi twice daily is effective in aRCC. We previously reported real-world experience of pem6w + axi demonstrating a comparable safety profile to pem3w + axi reported in Keynote 426, with the added benefit of less frequent hospital visits. Here we present updated results on progression free survival (PFS) and landmark analyses of overall survival (OS) at 6, 9 and 12-months. Methods: Electronic medical records of pts on pem6w + axi between 1st May 2020 & 1st June 2021 in two large cancer centres in Scotland were analysed retrospectively for pts’ characteristics, efficacy and treatment related adverse events (TRAE). A data cut-off of 1st June 2022 was applied. Results: A total of 93 pts were identified (baseline demographics previously reported). 74 pts (80%) had clear cell histology, 19 pts (20%) had non-clear cell and 11 pts (12%) had sarcomatoid component. Approximately half had previous nephrectomy (46 pts). 15 (16%), 46 (50%) and 32 (34%) pts respectively were classified as favourable, intermediate, and poor risk group as per international metastatic renal cell carcinoma database consortium (IMDC) criteria. The median follow-up was 13 months (inter-quartile range [IQR] 8-17). At data cut off, 59 (63%) had progressed or died, with median PFS of 10.7 (IQR: 4.6-not reached) months. At landmark time-points of 6, 9 and 12 months 63 (68%), 50 (54%) and 42 (45%) of pts were progression free (Table). The median OS was not reached and follow up continues. At landmark time-points of 6, 9 and 12 months 88 (95%), 69 (74%) and 65 (70%) of pts were alive (Table). Clinician assessed radiological response was evaluable in 87 pts. Overall response rate (ORR), including partial response and complete response, was noted in 51 pts (59%). Clinical benefit rate including pts with ORR and stable disease was seen in 74 pts (85%). 82 pts (88%) had any grade and 28 pts (30%) had grade 3/4 TRAE. Any grade immune related AE (irAE) occurred in 62 pts (67%) and grade 3/4 in 19 pts (20%); g3/4 transaminitis (10%), colitis (8%), nephritis (2%) and skin (2%). Any grade AE due to axi occurred in 69 (74%) and grade 3/4 AE in 14 pts (15%). 25pts (27%) on Pem and 19pts (20%) on axi discontinued treatment due to TRAE. Conclusions: Our real-world experience demonstrates that pem6w + axi appears to have comparable efficacy and safety profile to pem3w + axi reported in Keynote 426 study. [Table: see text]