High Rates of Remission with the Initial Treatment of Oral Azacitidine Plus CHOP for Peripheral T-Cell Lymphoma (PTCL): Clinical Outcomes and Biomarker Analysis of a Multi-Center Phase II Study

▪ Nodal PTCL with T-follicular helper phenotype (PTCL-TFH), which includes angioimmunoblastic T-cell lymphoma, is characterized by recurrent mutations affecting epigenetic regulators. Azacitidine, a DNA demethylating agent, has shown clinical activity as a single agent and in combination in R/R PTCL. We report the mature findings, including survival outcome and biomarker analysis, of the first study of oral azacitidine (CC-486) plus CHOP as initial treatment for PTCL (ClinicalTrials.gov - NCT03542266). This phase 2 study prioritized enrollment of PTCL-TFH. Subjects received CHOP on day 1 of each cycle for 6 cycles. Oral azacitidine (aza) priming at 300 mg daily was administered for 7 days prior to C1 of CHOP, and for 14 days before CHOP C2-6. The primary endpoint was CR per 2014 IWG criteria. Secondary endpoints included ORR, safety and survival. Correlative biomarker studies assessed mutation profile by whole exome NGS with germline control, genome-wide DNA methylation sequencing by RRBS, and gene expression by RNA-sequencing of paired tumor samples before and after aza priming prior to C1D1 chemotherapy. Survivals were estimated by Kaplan-Meier analysis, and log-rank tests were performed to correlate biomarkers to survival outcomes. A total of 21 subjects with previously untreated PTCL, including 17 with PTCL-TFH (81%), 3 with PTCL-NOS (14%), were enrolled and received treatment at 4 centers. The median age was 66 years (range 22-77), 19 (90%) had stage III/IV disease, 10 (48%) had elevated LDH, 7 (35%) had bone marrow involvement, and 9 (43%) had IPI 3-5. Treatment-emergent grade 3-4 hematologic toxicities included neutropenia (71%), thrombocytopenia (10%) and anemia (14%), with febrile neutropenia uncommon (14%). Grade 3-4 non-hematologic toxicities included fatigue (14%), hyponatremia (14%), diarrhea (5%), anorexia (5%), vomiting (5%), rash (5%), and elevated ALT (4.8%). There was no treatment-related mortality on study. As of July 2021 at a median follow-up of 21 months (range 16-30 months), 20 subjects were evaluable for primary endpoint, with one withdrawal after cycle 1. The end-of-treatment responses were all CRs, including CR at 75% (90%CI of 54.4 - 89.6%) for all evaluable patients (n=20) and 88.2% for PTCL-TFH (n=17). The 2-yr PFS was 65.8% (95%CI of 43.4-88.1%) for all patients, and 69.2% (95%CI of 46.7-91.7%) for PTCL-TFH. The 2-yr OS was 68% (95%CI of 46.7-89.2%) for all patients, and 75.6% (95%CI of 54.8-96.5%) for PTCL-TFH. The median PFS