Arcus Biosciences Inc. (RCUS): ESMO Abstracts Released: What We Learned from Belz's LS-012 Failure and LS-011 OS Miss for Casdatifan

ESMO abstracts were released Sunday including those for belzutifan's LITESPARK-011 and LITESPARK-012 studies in advanced ccRCC. In the 1L Ph.3 LS-012 study, both the belz triplet and MK-1308A triplet did not improve efficacy vs. control: the belz arm showed mPFS of 20.8 months vs. 23.7 months (HR 1.08), mOS of 52 months vs. NR (HR 1.04), and ORR of 69% vs. 76%. Higher toxicity led to discontinuation of any drug in 51.6% vs. 36.2% of patients, limiting pembro and lenva exposure to ~14-18 months vs. 21-22 months. We see limited read-through to cas from LS-012 given the compressed therapeutic window and RCUS's decision not to pursue cas with pembro+lenva in 1L, instead using better-tolerated backbones such as nivo+ipi or pembro+axitinib. In the final analysis of 2L Ph.3 LS-011, belz plus lenva maintained mPFS benefit over cabo (14.8 vs. 10.8 months; HR 0.74) but did not achieve statistically significant OS improvement (mOS 33.7 vs. 28.6 months; HR 0.85;