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OA 07 - Biomarker for Lung Cancer (ID 659)
- Event: WCLC 2017
- Type: Oral
- Track: Biology/Pathology
- Presentations: 1
- Moderators:Philip Christopher Mack, Shinichi Toyooka
- Coordinates: 10/16/2017, 15:45 - 17:30, Room 503
OA 07.03a - Impact of Tumor Mutation Burden on the Efficacy of Nivolumab or Nivolumab + Ipilimumab in Small Cell Lung Cancer: An Exploratory Analysis of CheckMate 032 (ID 11063)
15:45 - 17:30 | Author(s): M.K. Callahan
CheckMate 032 is a phase 1/2 clinical trial evaluating nivolumab ± ipilimumab in solid tumors, including small cell lung cancer (SCLC). Initial results have shown durable responses and encouraging survival, with benefit seen regardless of PD-L1 status. There is a need for improved biomarkers in SCLC. SCLC is nearly universally found in smokers and is characterized by high tumor mutation burden (TMB). The association of high TMB and clinical benefit from nivolumab ± ipilimumab in patients with SCLC was evaluated in an exploratory analysis of CheckMate 032.
CheckMate 032 evaluated nivolumab ± ipilimumab in non-randomized and randomized cohorts, which were pooled for this analysis. Whole exome sequencing (WES) was conducted on tumor and matched blood samples. TMB was defined as the total number of nonsynonymous somatic mutations. For the exploratory analyses, patients were equally divided into TMB tertiles (defined as low, medium, and high). Overall survival (OS) and progression-free survival (PFS) were estimated using Kaplan-Meier methods.
Among 401 patients in the intent-to-treat (ITT) population, 211 (53%) had an evaluable TMB result for these analyses (86% of the 246 patients with tissue available to attempt WES). Baseline characteristics and outcomes were similar between the ITT and TMB-evaluable populations. In TMB-evaluable patients treated with nivolumab (n=133), objective response rate (ORR), PFS, and OS were improved in the high TMB cohort vs the medium and low TMB cohorts (ORR: 21.3% vs 6.8% and 4.8%; 1-year PFS: 21.2% vs 3.1% and not calculable; 1-year OS: 35.2% vs 26.0% and 22.1%). Similar benefits were seen in TMB-evaluable patients treated with nivolumab + ipilimumab (n=78) in the high vs medium and low TMB cohorts (ORR: 46.2% vs 16.0% and 22.2%; 1-year PFS: 30.0% vs 8.0% and 6.2%; 1-year OS 62.4% vs 19.6% and 23.4%).
In patients with SCLC, efficacy with nivolumab ± ipilimumab was enhanced in those with high TMB. Among patients with high TMB, ORR and 1-year OS rates were approximately double with nivolumab + ipilimumab compared with nivolumab monotherapy. TMB has a potential role as a biomarker in lung cancer. Optimization of TMB cutoff and prospective investigation are warranted.Acknowledgements: All authors contributed to and approved the abstract; writing and editorial assistance was provided by Beth Burke, PhD, CMPP, of Evidence Scientific Solutions, funded by Bristol-Myers Squibb.Trial Registration: clinicaltrials.gov, NCT01928394
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