Abstract CT165: An open label, multi-cohort, phase Ib study of xentuzumab and abemaciclib: Preliminary results from the advanced non-small cell lung cancer (NSCLC) cohort

Abstract

Abstract Introduction: Insulin-like growth factor (IGF) signaling and the cyclin D-cyclin-dependent kinase (CDK) 4 & 6-retinoblastoma pathway are implicated in cancer progression and treatment resistance. Activation of the IGF receptor results in upregulation of cyclin D1 and progression through the cell cycle. Dual inhibition of IGF and CDK 4 & 6 should lead to decreased cell proliferation through disruption of cell-cycle progression. This phase Ib trial assessed safety and preliminary efficacy of xentuzumab, an IGF-ligand neutralizing antibody, in combination with abemaciclib, a CDK 4 & 6 inhibitor. In a dose-finding cohort in patients (pts) with solid tumors, the recommended phase II dose was determined as xentuzumab 1000 mg weekly intravenously plus abemaciclib 150 mg every 12 hours (Q12h) orally. Here, we present data from an expansion cohort in pts with NSCLC. Methods: Eligible pts had stage IV NSCLC with measurable disease which had progressed after platinum-based chemotherapy and immunotherapy, and had either received 1-2 prior chemotherapies for advanced/metastatic disease or were judged ineligible for further standard second-line chemotherapy. Prior CDK 4 & 6 inhibitor therapy was not permitted. Pts received xentuzumab 1000 mg weekly plus abemaciclib 150 mg Q12h until disease progression or intolerability of study medication. The primary endpoint was objective response defined as best overall response of complete response or partial response (PR) per RECIST 1.1. Secondary endpoints included progression-free survival (PFS). Results: 25 pts with NSCLC were treated (17 male [68%], median age 64 years [range 53-76]). 4 pts remained on treatment at time of analysis. Median treatment exposure was 1.6 months (range 0.5-19.7). Of 19 pts evaluable for response, 1 had a best overall response of PR (65% target lesion shrinkage), 9 had stable disease (duration ≥24 weeks in 3 pts) and 9 had progressive disease. Median PFS was 2.1 months (95% CI 1.2-5.3). All pts experienced adverse events (AEs) and 23 experienced treatment-related AEs (TRAEs), most commonly diarrhea (n=15; 60%), nausea (n=10; 40%) and platelet count decreased (n=8; 32%). The most common grade ≥3 TRAEs were thrombocytopenia (n=4; 16%) and neutropenia (n=3; 12%). No AEs of hyperglycemia or blood glucose increased were reported. Serious AEs were experienced by 13 pts (52%). 2 pts had fatal serious AEs due to disease progression and respiratory failure. Conclusion: The combination of xentuzumab and abemaciclib showed preliminary efficacy in pts with NSCLC who had progressed on chemotherapy and an immune checkpoint inhibitor. One PR was reported. The combination had a manageable safety profile. Citation Format: Patricia LoRusso, Javier García-Corbacho, Fadi S. Braiteh, Anthony Gonçalves, Francesco Ricci, Hiroji Iwata, Marta Capelán, Marie Paule Sablin, Aleix Prat, Molly Catherine Hardebeck, Marta Puig, Dennis Chin-Lun Huang, Mingchi Hsu, Douglas Yee. An open label, multi-cohort, phase Ib study of xentuzumab and abemaciclib: Preliminary results from the advanced non-small cell lung cancer (NSCLC) cohort [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT165.