Autologous Stem Cell Transplantation after Conditioning with Chidamide Plus Carmustine, Etoposide, Cytarabine, and Cyclophosphamide (Chi-BEAC) for Treatment of High-Risk and Relapsed/Refractory Aggressive Lymphoma: Multi-Center, Single-Arm, Open-Label Phase II Clinical Trial

Background:

Chidamide, as a novel subtype-selective histone deacetylase inhibitors (HDACi), can directly inhibit tumor cell cycle progression and induce tumor cell apoptosis, inhibit phenotypic transformation of tumor cells and pro-drug resistance/pro-metastasis activity of the microenvironment, induce differentiation of tumor stem cells, and reverse epithelial-mesenchymal transformation of tumor cells, thereby restoring the sensitivity of drug-resistant tumor cells to drugs and enhancing the effect of chemotherapy agents through loosening chromatin and exposing DNA. The efficacy and safety of chidamide-BEAC (carmustine, etoposide, cytarabine, and cyclophosphamide, Chi-BEAC) conditioning regimen combined with autologous stem cell transplantation (ASCT) were evaluated in a current phase II clinical trial for the treatment of high-risk and relapsed/refractory aggressive lymphoma.

Methods: A total of 70 patients with high-risk diffuse large B-cell lymphoma (DLBCL), peripheral T-cell lymphoma (PTCL), or mantle cell lymphoma (MCL) who had achieved complete remission (CR) or partial remission (PR) after first-line therapy or second-/third-line therapy were recruited from January 2018 to June 2021. Three of the patients were not evaluated after ASCT and two patients withdrew from the study; 65 patients were then evaluated for the effectiveness of Chi-BEAC treatment.

Results: DLBCL and MCL are referred as B-cell non-Hodgkin lymphoma (B-NHL) and PTCL is referred as T and NK-cell non-Hodgkin lymphoma (T&NK-NHL) in the study. The median neutrophil engraftment time was 10 d (7-13 d) and median platelet engraftment time was 11 d (8-13 d).

The CR rate at 3-6 months after transplantation was 75.4% in the 65 evaluable patients. The median progression free survival (PFS) and overall survival (OS) had not reached at the end of the follow-up period (median 18.1 month; range 1.8-42.0 months). The estimated PFS and OS at 24 months was 78.5% and 84.2%, respectively. Stratified analyses showed that in patients with B-NHL who previously received first-line treatment, the CR rate at 3-6 months after transplantation was 77.8%, and 2-year PFS was 74.8%. The survival rate might be better than previously reported for SWOG9704 (Stiff et al., 2013; PMID 24171516)-a 2-year PFS of 69%-and for DLCL04 (Chiappella et al., 2017; PMID 28668386)-a 2-year failure-free survival of 71%. In our patients with B-NHL who previously received second-/third-line treatments, the CR rate at 3-6 months after transplantation was 71.4%, and 2-year PFS was 77.1%. The survival rate might also be higher than previously reported for the CORAL trial (Gisselbrecht et al., 2010; PMID: 20660832), which showed a 2-year PFS of approximately 65%. In our patients with T&NK-NHL the CR rate at 3-6 months after transplantation was 73.3%, and 2-year PFS was 93.3%, The survival rate might be higher than previously reported for the NLG-T-01 trial (Francesco d'Amore et al., 2012; PMID: 22851556), which showed a 2-year PFS of approximately 55%. PFS stratification analysis showed that previous treatment outcomes affected the PFS: patients who had achieved CR before transplantation demonstrated better PFS than patients who had achieved PR (P = 0.199), while there was no significant difference between patients with different pathological subtypes (B or T&NK-NHL) or different risk groups.

Most non-hematological adverse events (AEs) were of grade 1/2. Grade 4 AE only occurred in one patient, i.e., γ-glutamyl transpeptidase (GGT) elevation. Grade 3 AEs that occurred in ≥ 5% of the patients included febrile agranulocytosis (37.7%), hypokalemia (24.7%), hyponatremia (23.4%), GGT elevation (9.1%), and diarrhea (5.2%), which were well tolerated.

Conclusions: This study showed that inclusion of the HDACi chidamide in conditioning regimen for ASCT greatly increased the PFS and OS, especially in patients with T&NK-NHL, and revealed an acceptable safety profile for refractory and relapsed lymphoma patients. Therefore, chidamide-containing conditioning regimen may be a great choice for patients with refractory and relapsed lymphoma, and awaits further confirmation by additional large-scale multi-center investigations.