The epigenetic immunomodulator, HBI-8000, enhances the response and reverses resistance to checkpoint inhibitors

BMC Cancer

Bob Goodenow¹  Farbod Shojaei¹  Mireille Gillings¹  Reid P. Bissonnette¹  Rosemary M. Cesario¹ 

[1] HUYABIO International, LLC, San Diego, CA, USA;

关键词: Histone deacetylase;    HDAC;    Epigenetics;    PD-1;    PD-L1;    Immune checkpoint;    Dendritic cells;    Checkpoint blockade;   

DOI  :  10.1186/s12885-021-08702-x

来源: Springer

【 摘 要 】

BackgroundTreatment with immune checkpoint inhibitors (ICIs) targeting CTLA-4 and the PD-1/PD-L1 axis is effective against many cancer types. However, due in part to unresponsiveness or acquired resistance, not all patients experience a durable response to ICIs. HBI-8000 is a novel, orally bioavailable class I selective histone deacetylase inhibitor that directly modifies antitumor activity by inducing apoptosis, cell cycle arrest, and resensitization to apoptotic stimuli in adult T cell lymphoma patients. We hypothesized that HBI-8000 functions as an epigenetic immunomodulator to reprogram the tumor microenvironment from immunologically cold (nonresponsive) to hot (responsive).MethodMice bearing syngeneic tumors (MC38 and CT26 murine colon carcinoma and A20 B-cell lymphoma were treated daily with HBI-8000 (orally), alone or in combination with PD-1, PD-1 L, or CTLA-4 antibodies. MC38 tumors were also analyzed in nanoString gene expression analysis.ResultsHBI-8000 augmented the activity of ICI antibodies targeting either PD-1, PD-L1 or CTLA-4, and significantly increased tumor regression (p < 0.05) in the above models. Gene expression analysis of the treated MC38 tumors revealed significant changes in mRNA expression of immune checkpoints, with enhanced dendritic cell and antigen-presenting cell functions, and modulation of MHC class I and II molecules.ConclusionsThese findings suggest that HBI-8000 mediates epigenetic modifications in the tumor microenvironment, leading to improved efficacy of ICIs, and provide strong rationale for combination therapies with ICIs and HBI-8000 in the clinical setting.PrecisAs an HDACi, HBI-8000 plays an important role in priming the immune system in the tumor microenvironment. The current preclinical data further justifies testing combination of HBI-8000 and ICIs in the clinic.

【 授权许可】

CC BY