Zakharia Y, McWilliams RR, Rixe O, Drabick J, Shaheen MF, Grossmann KF, Kolhe R, Pacholczyk R, Sadek R, Tennant LL, Smith CM, Kennedy EP, Link CJ Jr, Vahanian NN, Yu J, Shen SS, Brincks EL, Rossi GR, Munn D, and Milhem M
Background: The indoleamine 2,3-dioxygenase (IDO) pathway is a key counter-regulatory mechanism that, in cancer, is exploited by tumors to evade antitumor immunity. Indoximod is a small-molecule IDO pathway inhibitor that reverses the immunosuppressive effects of low tryptophan (Trp) and high kynurenine (Kyn) that result from IDO activity. In this study, indoximod was used in combination with a checkpoint inhibitor (CPI) pembrolizumab for the treatment for advanced melanoma., Methods: Patients with advanced melanoma were enrolled in a single-arm phase II clinical trial evaluating the addition of indoximod to standard of care CPI approved for melanoma. Investigators administered their choice of CPI including pembrolizumab (P), nivolumab (N), or ipilimumab (I). Indoximod was administered continuously (1200 mg orally two times per day), with concurrent CPI dosed per US Food and Drug Administration (FDA)-approved label., Results: Between July 2014 and July 2017, 131 patients were enrolled. (P) was used more frequently (n=114, 87%) per investigator's choice. The efficacy evaluable population consisted of 89 patients from the phase II cohort with non-ocular melanoma who received indoximod combined with (P).The objective response rate (ORR) for the evaluable population was 51% with confirmed complete response of 20% and disease control rate of 70%. Median progression-free survival was 12.4 months (95% CI 6.4 to 24.9). The ORR for Programmed Death-Ligand 1 (PD-L1)-positive patients was 70% compared with 46% for PD-L1-negative patients. The combination was well tolerated, and side effects were similar to what was expected from single agent (P)., Conclusion: In this study, the combination of indoximod and (P) was well tolerated and showed antitumor efficacy that is worth further evaluation in selected patients with advanced melanoma., Competing Interests: Competing interests: YZ reports personal fees for Advisory Board: Amgen, Roche Diagnostics, Novartis, Janssen, Eisai, Exelixis, Castle Bioscience, Array, Bayer, Pfizer, Clovis, and EMD serono. Grant/research support from Institutional clinical trial support from NewLink Genetics, Pfizer, Exelixis, and Eisai. DSMC honorarium: Janssen Research and Development. Consultant honorarium: Pfizer, Novartis. RRM reports personal fees from Newlink Genetics, outside the submitted work. MFS and RK report personal fees from Illumina Inc, BMS, and Qiagen. DM reports grants from NewLink Genetics, during the conduct of the study; grants and personal fees from NewLink Genetics, outside the submitted work. In addition, DM has a patent US patent 8,232,313 licensed to NewLink Genetics, and a patent US patent 6,451,840 licensed to NewLink Genetics. MM reports personal fees from Blueprints Medicine, Immunocore, Amgen, Treiza, Array Biopharma, Biontech, and Novartis. LLT, CMS, EPK, CJL, NNV, JY, ELB, and GRR were employed by NewLink Genetics at the time of conducting the study. All remaining authors have declared no conflicts of interest., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)