A Phase II Trial of Prexasertib (LY2606368) in Patients With Extensive-Stage Small-Cell Lung Cancer

Background: This study assessed the checkpoint kinase 1 inhibitor prexasertib in patients with extensive-stage small-cell lung cancer (ED-SCLC). Patients and Methods: This was a parallel-cohort phase II study of 105 mg/m2 prexasertib once every 14 days for patients who progressed after no more than two prior therapies and had platinum-sensitive (Cohort 1) or platinum-resistant/platinum-refractory (Cohort 2) disease. The primary endpoint was objective response rate (ORR). Secondary endpoints included disease control rate (DCR), progression-free survival (PFS), overall survival (OS), safety, and pharmacokinetics. Exploratory endpoints included biomarker identification and assessment of an alternative regimen (Cohort 3: 40 mg/m2 days 1-3, 14-day cycle). Results: In Cohort 1 (n = 58), ORR was 5.2%; DCR, 31%; median PFS, 1.41 months (95% confidence interval [CI], 1.31-1.64); and median OS, 5.42 months (95% CI, 3.75-8.51). In Cohort 2 (n = 60), ORR was 0%; DCR, 20%; median PFS, 1.36 months (95% CI, 1.25-1.45); and median OS, 3.15 months (95% CI, 2.27-5.52). The most frequent all-grade, related, treatment-emergent adverse events were decreased neutrophil count (Cohort 1, 69.6%; Cohort 2, 73.3%), decreased platelet count (Cohort 1, 51.8%; Cohort 2, 50.0%), decreased white blood cell count (Cohort 1, 28.6%; Cohort 2, 40.0%), and anemia (Cohort 1, 39.3%; Cohort 2, 28.3%). Eleven patients (19.6%) in Cohort 1 and one patient (1.7%) in Cohort 2 experienced grade ?3 febrile neutropenia. Prexasertib pharmacokinetics were consistent with prior studies. Cohort 3 outcomes were similar to those of Cohorts 1 and 2. No actionable biomarkers were identified. Conclusion: Prexasertib did not demonstrate activity to warrant future development as monotherapy in ED-SCLC. © 2021 The Authors Boehringer Ingelheim; Amgen; Bristol-Myers Squibb; Eli Lilly and Company; Pfizer; Astellas Pharma US; AstraZeneca; Merck; Novartis; Roche; AbbVie; University of Michigan; Takeda Pharmaceuticals U.S.A.; Merck Sharp and Dohme; PTC Therapeutics; TG Therapeutics; NIHR Biomedical Research Centre, Royal Marsden NHS Foundation Trust/Institute of Cancer Research; Bayer Fund; National Institute for Health Research; European Commission; Daiichi-Sankyo; Oryzon Genomics; Otsuka Pharmaceutical; UCLH Biomedical Research Centre We thank the patients who participated in this trial and the study coordinators, nurses, nurse practitioners, clinical research assistants, and doctors who assisted with the research. The authors also thank Erin Wagner from BioStat Solutions, Inc., for statistical support and Lisa Golden, Rod Decker, and Elizabeth Spoljoric for their input and contributions to the study. MDF is supported by the University College London/University College London Hospitals NHS Foundation Trust (UCLH) National Institute for Health Research (NIHR) Biomedical Research Centre and runs early phase studies in the NIHR UCLH Clinical Research Facility supported by the University College London Experimental Cancer Medicine Centre. Eli Lilly and Company contracted with Syneos Health for writing support provided by Andrea D. Humphries, PhD, and editing support provided by Noelle Gasco. L.A. Byers reports receiving research funding and fees as an advisor or consultant from AstraZeneca, GenMab, and Sierra Oncology; research funding from Tolero Pharmaceuticals; and fees as an advisor or consultant from Bristol Myers Squibb, Althia, Merck, Pfizer, PharmaMar, AbbVie, Jazz Pharmaceuticals, Genentech, and Debiopharm Group. A. Navarro reports receiving fees as an advisor or consultant from Pfizer and Boehringer Ingelheim; fees from Roche and AstraZeneca speakers’ bureaus; fees for expert testimony from Oryzon Genomics and MedSIR; and fees or reimbursement for travel, accommodations, or other expenses from Roche, Pfizer, and Boehringer Ingelheim. M. Johnson reports grant funding to her institution from Eli Lilly and Company, Abbvie, Acerta, Adaptimmune, Amgen, Apexigen, Arcus Biosciences, Array BioPharma, Artios Pharma, AstraZeneca, Atreca, BeiGene, BerGenBio, Boehringer Ingelheim, Calithera Biosciences, Checkpoint Therapeutics, Corvus Pharmaceuticals, Curis, CytomX, Daiichi Sankyo, Dracen Pharmaceuticals, Dynavax, EMD Serono, Genentech/Roche, Genmab, Genocea Biosciences, GlaxoSmithKline, Gritstone Oncology, Guardant Health, Harpoon, Hengrui Therapeutics, Immunocore, Incyte, Janssen, Jounce Therapeutics, Kadmon Pharmaceuticals, Loxo Oncology, Lycera, Merck, Mirati Therapeutics, Neovia Onclogy, Novartis, OncoMed Pharmaceuticals, Pfizer, PMV Pharmaceuticals, Regeneron Pharmaceuticals, Ribon Therapeutics, Rubius Therapeutics, Sanofi, Seven and Eight Biopharmaceuticals/Birdie Biopharmaceuticals, Shattuck Labs, Silicon Therapeutics, Stem CentRx, Syndax Pharmaceuticals, Takeda Pharmaceuticals, Tarveda, TCR2 Therapeutics, TMUNITY Therapeutics, University of Michigan, and WindMIL; receiving fees for consulting services from Eli Lilly and Company, Abbvie, Amgen, AstraZeneca, Atreca, Boehringer Ingelheim, Calithera Biosciences, Checkpoint Therapeutics, Daiichi Sankyo, EMD Serono, Genentech/Roche, GlaxoSmithKline, Gritstone Oncology, Guardant Health, Incyte, Janssen, Loxo Oncology, Merck, Mirati Therapeutics, Novartis, Pfizer, Ribon Therapeutics, Sanofi, WindMIL, Achilles Therapeutics, Bristol Myers Squibb, Eisai, G1 Therapeutics, and Association of Community Cancer Centers; and receiving fees for consulting services performed by her spouse from Astellas and Otsuka Pharmaceuticals. K.H. Dragnev reports funding to the institution for the conduct of the trial from Eli Lilly and Company and support to the institution for conduct of company-sponsored trials from Merck, Roche/Genentech, G1 Therapeutics, Io Therapeutics, and Novartis. S. McNeely reports receiving personal fees and non-financial support from Eli Lilly and Company. A.B. Lin and spouse are both employees and shareholders of Eli Lilly and Company. M. Forster reports receiving educational grants from Merck Sharp & Dohme for the EACH study and the POPPY study, from Boehringer Ingelheim for the DARWIN1 study, and from AstraZeneca for the ORCA2 study, as well as fees for advisory and consultancy work from Achilles, AstraZeneca, Bristol Myers Squibb, Merck, Nanobiotix, Novartis, Pfizer, Pharmamar, Roche, Takeda, Bayer, and Guardant Advisory. The remaining authors have stated that they have no conflicts of interest.