Histone deacetylases inhibitor chidamide synergizes with humanized PD1 antibody to enhance T-cell chemokine expression and augment Ifn-γ response in NK-T cell lymphoma

Combination of chidamide and PD-1 blockade in Refractory/Relapsed aggressive large B-cell lymphomas with high risk of failing CAR-T therapy

BACKGROUND

Refractoriness and relapse after chimeric antigen receptor T-cell therapy have emerged as major challenges for immunotherapy of aggressive large B-cell lymphoma. Thus far, there is no consensus on how to address treatment failure and whether to administer maintenance therapy following CAR-T cell therapy.

METHODS

From August 2017 through November 2022, 52 patients with refractory/relapsed aggressive LBCL who had a high risk of resistance to CAR-T cell therapy were given chidamide in combination with a PD-1 inhibitor as maintenance therapy following either CAR19/22 T-cell cocktail therapy or CAR19/22 T-cell cocktail therapy plus autologous stem cell transplantation (ASCT). Another 52 aggressive LBCL patients who had comparable baseline characteristics and received similar therapeutic regimens but did not receive any interventions following CAR-T cell therapy or CAR-T cell therapy plus ASCT were regarded as the control group to evaluate the efficacy and safety of the combination of chidamide and a PD-1 inhibitor.

RESULTS

Among the 52 patients who received chidamide and a PD-1 inhibitor as maintenance therapy, with a median follow-up of 26.5 months (range: 1.1-53.8), neither the median progression-free survival (PFS) nor overall survival (OS) was reached, and the expected 2-year OS and PFS rates were 89 % and 77 %, respectively, which were superior to those of the control group (p < 0.001). Long-term chidamide administration and a specific genetic subtype of EZB were strongly associated with a better response after chidamide plus PD-1 blockade therapy. Additionally, long-term chidamide administration was significantly associated with prolonged persistence and reactivation of CD19-directed CAR-T cells in the peripheral blood. Adverse effects (AEs) were moderate and reversible, and no treatment-related deaths occurred.

CONCLUSION

Our results indicate that the combination of chidamide and PD-1 blockade as maintenance therapy could improve the outcomes of aggressive LBCL patients at high risk of failing CAR-T cell therapy.

Sintilimab (anti-PD-1 antibody) plus chidamide (histone deacetylase inhibitor) in relapsed or refractory extranodal natural killer T-cell lymphoma (SCENT): a phase Ib/II study

Anti-PD-1 antibodies are a favorable treatment for relapsed or refractory extranodal natural killer T cell lymphoma (RR-ENKTL), however, the complete response (CR) rate and the duration of response (DOR) need to be improved. This phase 1b/2 study investigated the safety and efficacy of sintilimab, a fully human anti-PD-1 antibody, plus chidamide, an oral subtype-selective histone deacetylase inhibitor in 38 patients with RR-ENKTL. Expected objective response rate (ORR) of combination treatment was 80%. Patients received escalating doses of chidamide, administered concomitantly with fixed-dose sintilimab in 21-days cycles up to 12 months. No dose-limiting events were observed, RP2D of chidamide was 30 mg twice a week. Twenty-nine patients were enrolled in phase 2. In the intention-to-treat population (n = 37), overall response rate was 59.5% with a complete remission rate of 48.6%. The median DOR, progression-free survival (PFS), and overall survival (OS) were 25.3, 23.2, and 32.9 months, respectively. The most common grade 3 or higher treatment-emergent adverse events (AEs) were neutropenia (28.9%) and thrombocytopenia (10.5%), immune-related AEs were reported in 18 (47.3%) patients. Exploratory biomarker assessment suggested that a combination of dynamic plasma ctDNA and EBV-DNA played a vital prognostic role. STAT3 mutation shows an unfavorable prognosis. Although outcome of anticipate ORR was not achieved, sintilimab plus chidamide was shown to have a manageable safety profile and yielded encouraging CR rate and DOR in RR-ENKTL for the first time. It is a promising therapeutic option for this population.

HDAC-targeting epigenetic modulators for cancer immunotherapy

HDAC inhibitors, which can inhibit the activity of HDAC enzymes, have been extensively studied in tumor immunotherapy and have shown potential therapeutic effects in cancer immunotherapy. To date, numerous small molecule HDAC inhibitors have been identified, but many of them suffer from limited clinical efficacy and serious toxicity. Hence, HDAC inhibitor-based combination therapies, and other HDAC modulators (e.g. PROTAC degraders, dual-acting agents) have attracted great attention with significant advancements achieved in the past few years due to their superior efficacy compared to single-target HDAC inhibitors. In this review, we overviewed the recent progress on HDAC-based drug discovery with a focus on HDAC inhibitor-based drug combination therapy and other HDAC-targeting strategies (e.g. selective HDAC inhibitors, HDAC-based dual-target inhibitors, and PROTAC HDAC degraders) for cancer immunotherapy. In addition, we also summarized the reported co-crystal structures of HDAC inhibitors in complex with their target proteins and the binding interactions. Finally, the challenges and future directions for HDAC-based drug discovery in cancer immunotherapy are also discussed in detail.

Results from a phase I trial of pembrolizumab plus vorinostat in relapsed/refractory B-cell non-Hodgkin lymphoma

Outcomes after programmed death-1 (PD-1) blockade in B-cell lymphomas are disappointing with few durable responses. Histone deacetylase inhibitors exhibit favorable immunomodulatory effects and demonstrate synergistic anti-tumor immune responses with anti-PD-1 therapy in preclinical models. We, therefore, developed a phase I study to evaluate the safety and preliminary efficacy of pembrolizumab with vorinostat in relapsed/refractory B-cell lymphomas. Patients were treated in a dose-escalation cohort using a Rolling 6 design followed by an expansion cohort at the recommended phase II dose (R2PD). Fifty-two patients were enrolled (32 Hodgkin and 20 non-Hodgkin lymphoma [NHL]). Here, we report safety data from the dose escalation cohort, and the toxicity and efficacy within NHL patients. Vorinostat was administered twice daily on days 1-5 and 8-12 (dose-level [DL]1: 100 mg; DL2: 200 mg) and pembrolizumab (200 mg) was administered on day 1 of each 3-week cycle. Of six patients treated at DL1, one had a dose-limiting toxicity (DLT) (Stevens-Johnson syndrome [SJS]), and one of six had a DLT at DL2 (thromboembolism); therefore, DL2 was the RP2D. The patient developing SJS was treated with corticosteroids, infliximab, and cyclosporine but ultimately died of invasive fungal infection from the extensive immunosuppression used to treat the SJS. The most common adverse events were hypertension, diarrhea, and cytopenias. Of 20 NHL patients, nine had follicular lymphoma (FL) and 11 had diffuse large B-cell lymphoma (DLBCL). Five DLBCL patients had primary mediastinal B-cell lymphoma (PMBL). The complete and overall response rates (CR and ORR) were 11% and 22% for FL and 45% and 55% for all DLBCL. Amongst DLBCL, the CR and ORR was 80% and 80% for PMBL and 17% and 33% for non-PMBL. In conclusion, pembrolizumab with vorinostat was tolerable and produced responses in relapsed/refractory B-cell NHL, with particularly notable efficacy in PMBL (clinicaltrials gov. Identifier: NCT03150329).

Advances and challenges of immunotherapies in NK/T cell lymphomas

Natural killer (NK)/T cell lymphoma (NKTCL) is a rare subtype of Epstein-Barr virus (EBV)-associated non-Hodgkin lymphoma characterized by poor clinical outcomes. It is more common in East Asian and Latin American countries. Despite the introduction of asparaginase/pegaspargase-based chemotherapy, the prognosis of patients with advanced NKTCL needs to be improved, and few salvage treatment options are available for relapsed/refractory patients who fail chemotherapy. Although many unknowns remain, novel treatment strategies to further improve outcomes are urgently needed. Immunotherapy has emerged and shown favorable antitumor activity in NKTCL, including monoclonal antibodies targeting immune checkpoint inhibitors, other receptors on the cellular membrane, and cellular immunotherapy, which could enhance immune cells attack on tumor cells. In this review, we provide an overview of recent immunotherapy in NKTCL, focusing on programmed cell death-1 (PD-1)/programmed cell death-ligand 1 (PD-L1), cytotoxic T lymphocyte-associated protein 4 (CTLA-4), chimeric antigen receptor (CAR) T cells, EBV-specific cytotoxic T lymphocytes, immunomodulatory agents, and other targeted agents, as well as the current progress and challenges in the field.

Current Approaches to Epigenetic Therapy

Epigenetic therapy is a promising tool for the treatment of a wide range of diseases. Several fundamental epigenetic approaches have been proposed. Firstly, the use of small molecules as epigenetic effectors, as the most developed pharmacological method, has contributed to the introduction of a number of drugs into clinical practice. Secondly, various innovative epigenetic approaches based on dCas9 and the use of small non-coding RNAs as therapeutic agents are also under extensive research. In this review, we present the current state of research in the field of epigenetic therapy, considering the prospects for its application and possible limitations.