Phase 2 Open-Label Study of Bortezomib, Cladribine, and Rituximab in Advanced, Newly Diagnosed, and Relapsed/Refractory Mantle-Cell and Indolent Lymphomas

[A comparison of C+SCAV and SEAM conditioning regimens in efficacy and safety in autologous hematopoietic stem cell transplantation for non-Hodgkin's lymphoma patients]

Objective: This study aimed to compare the efficacy and safety of cladribine, smustine, etoposide, cyclophosphamide, and cytarabine (C+SCAV) and smustine, etoposide, cytarabine, and melphalan (SEAM) conditioning regimens in autologous stem cell transplantation (auto-HSCT) for non-Hodgkin's lymphoma (NHL) . Methods: A retrospective analysis was conducted on 61 NHL patients who received auto-HSCT in the Department of Hematology, the First Affiliated Hospital of Suzhou University, from March 2018 to May 2021. The C + SCAV group and SEAM group had 19 and 42 patients, respectively. Results: ① Among the 61 patients with NHL, 37 were male and 24 were female. The median age was 48 (21-66) years old. There were 19 cases in the C+SCAV group and 42 cases in the SEAM group. There was no significant difference in the baseline characteristics between the two groups (P>0.05) . ② The median time to neutrophil and platelet engraftment in the C+SCAV cohort were 10 (8-15) days and 13 (9-22) days, respectively, which does not differ from the SEAM group (P=0.103, P=0.403) . ③ No differences existed between the two groups in terms of survival. The 1-year progression-free survival (PFS) was (76.5±10.3) % for patients receiving C+SCAV and (78.4±6.8) % for those who received SEAM (P=0.841) . The 1-year overall survival was 100.0% for the C+SCAV group and 95.2±3.3% for the SEAM group (P=0.339) . ④The 1-year PFS of patients with complete remission in the C+SCAV group was similar to those who in the SEAM group [ (92.3±7.4) % vs (82.5±7.2) %, P=0.406]. ⑤ The incidence of non-hematological serious adverse events (≥ grade 3) in the C+SCAV group and SEAM group were 10.5% (2/19) and 40.5% (17/42) (P=0.013) , the incidence of severe mucositis was 5.3% (1/19) and 31.0% (13/42) (P=0.015) , and the incidence of severe infection (≥ grade 3) was 10.5% (2/19) and 19.0% (8/42) (P=0.389) , respectively. Conclusion: C + SCAV conditioning regimen appeared to be no different from the SEAM regimen in terms of survival. It can lower the incidence of SAE and does not increase the risk of severe infection. As a result, it can be used as an alternative conditioning regimen for lymphoma patients undergoing auto-HSCT.

P300/CBP inhibition sensitizes mantle cell lymphoma to PI3Kδ inhibitor idelalisib

Mantle cell lymphoma (MCL) is a lymphoproliferative disorder lacking reliable therapies. PI3K pathway contributes to the pathogenesis of MCL, serving as a potential target. However, idelalisib, an FDA-approved drug targeting PI3Kδ, has shown intrinsic resistance in MCL treatment. Here we report that a p300/CBP inhibitor, A-485, could overcome resistance to idelalisib in MCL cells in vitro and in vivo. A-485 was discovered in a combinational drug screening from an epigenetic compound library containing 45 small molecule modulators. We found that A-485, the highly selective catalytic inhibitor of p300 and CBP, was the most potent compound that enhanced the sensitivity of MCL cell line Z-138 to idelalisib. Combination of A-485 and idelalisib remarkably decreased the viability of three MCL cell lines tested. Co-treatment with A-485 and idelalisib in Maver-1 and Z-138 MCL cell xenograft mice for 3 weeks dramatically suppressed the tumor growth by reversing the unsustained inhibition in PI3K downstream signaling. We further demonstrated that p300/CBP inhibition decreased histone acetylation at RTKs gene promoters and reduced transcriptional upregulation of RTKs, thereby inhibiting the downstream persistent activation of MAPK/ERK signaling, which also contributed to the pathogenesis of MCL. Therefore, additional inhibition of p300/CBP blocked MAPK/ERK signaling, which rendered maintaining activation to PI3K-mTOR downstream signals p-S6 and p-4E-BP1, thus leading to suppression of cell growth and tumor progression and eliminating the intrinsic resistance to idelalisib ultimately. Our results provide a promising combination therapy for MCL and highlight the potential use of epigenetic inhibitors targeting p300/CBP to reverse drug resistance in tumor.

Management of Drug Resistance in Mantle Cell Lymphoma

Mantle cell lymphoma (MCL) is a rare but aggressive B-cell hemopathy characterized by the translocation t(11;14)(q13;q32) that leads to the overexpression of the cell cycle regulatory protein cyclin D1. This translocation is the initial event of the lymphomagenesis, but tumor cells can acquire additional alterations allowing the progression of the disease with a more aggressive phenotype and a tight dependency on microenvironment signaling. To date, the chemotherapeutic-based standard care is largely inefficient and despite the recent advent of different targeted therapies including proteasome inhibitors, immunomodulatory drugs, tyrosine kinase inhibitors, relapses are frequent and are generally related to a dismal prognosis. As a result, MCL remains an incurable disease. In this review, we will present the molecular mechanisms of drug resistance learned from both preclinical and clinical experiences in MCL, detailing the main tumor intrinsic processes and signaling pathways associated to therapeutic drug escape. We will also discuss the possibility to counteract the acquisition of drug refractoriness through the design of more efficient strategies, with an emphasis on the most recent combination approaches.

Phase 1-2 study of vorinostat (SAHA), cladribine and rituximab (SCR) in relapsed B-cell non-Hodgkin lymphoma and previously untreated mantle cell lymphoma

Altered DNA methylation and histone acetylation in lymphoma provided the rationale for using vorinostat (SAHA), cladribine and rituximab (SCR) in non-Hodgkin lymphomas (NHL) in this phase 1-2 study (NCT00764517). Treatment included cladribine 5 mg/m² intravenously (IV) (days 1-5), rituximab 375 mg/m² IV (weekly 4× for cycle 1 and 1×/month) and vorinostat orally once daily (days 1-14) every 28 days for up to six cycles. Phase 1 included relapsed patients (n = 10) in a standard 3 + 3 dose escalation design (vorinostat: 200, 300 and 400 mg). No dose-limiting toxicities were seen. The phase 2 dose for vorinostat was 400 mg po (days 1-14). The majority of phase 2 patients had mantle cell lymphoma (MCL) (n = 57; 39 previously untreated, 10 relapsed). The primary objective was objective response rate [complete response (CR) + partial response] which was 39% (7/18) in relapsed patients and 97% (38/39) with 80% (31/39) attaining a CR in previously untreated MCL. At a median follow-up of 42 months, median progression-free survival (PFS) and overall survival (OS) for relapsed NHL were 19·5 [95% confidence interval (CI): 2·0-33·0] and 25·0 (95% CI: 12·0-45·0) months respectively. Median PFS for previously untreated MCL was 84·0 months; OS could not be estimated. Toxicities were primarily haematological.

Mantle cell lymphoma and its management: where are we now?

Mantle cell lymphoma is a relatively new recognized hematological malignant disease, comprising of 2.5–6% non-Hodgkin’s lymphomas. The complexity of its clinical presentations (nodular pattern, diffuse pattern, and blastoid variant), variety in disease progression, and treatment response, make this disease a research focus to both experimental oncology and clinical oncology. Overexpression of cyclin D1 and chromosome t(11,14) translocation are the known molecular biomarkers of this disease. Mantle cell international prognostic index (MIPI), ki-67 proliferation index, and TP53 mutation are emerging as the prognostic biomarkers. Epigenetic profile variance and SOX11 gene expression profile correlate with treatment response. Over the years, the treatment strategy has been gradually evolving from combination chemotherapy to combination of targeted therapy, epigenetic modulation therapy, and immunotherapy. In a surprisingly short period of time, FDA specifically approved 4 drugs for treating mantle cell lymphoma: lenalidomide, an immunomodulatory agent; Bortezomib, a proteasome inhibitor; and Ibrutinib and acalabrutinib, both Bruton kinase inhibitors. Epigenetic agents (e.g. Cladribine and Vorinostat) and mTOR inhibitors (e.g. Temsirolimus and Everolimus) have been showing promising results in several clinical trials. However, treating aggressive variants of this disease that appear to be refractory/relapse to multiple lines of treatment, even after allogeneic stem cell transplant, is still a serious challenge. Developing a personalized, precise therapeutic strategy combining targeted therapy, immunotherapy, epigenetic modulating therapy, and cellular therapy is the direction of finding a curative therapy for this subgroup of patients.

Current trials for frontline therapy of mantle cell lymphoma

Mantle cell lymphoma (MCL) is a rare and incurable subtype of non-Hodgkin’s lymphoma that generally affects older individuals. However, the use of high-dose therapy and autologous stem cell transplant has improved significantly the prognosis of this hematological malignancy, but at the cost of increased toxicities, such as acute toxic death and secondary malignancies. But thanks to a rising understanding of the biology of MCL, the explosion of specifically targeted new efficacious agents, immunotherapy agents, and cellular therapies in the frontline setting, the prognosis of MCL is expected to improve dramatically.

The initial treatment of MCL is currently not standardized and the therapeutic landscape of MCL is rapidly evolving. This review provides an extensive overview of the current frontline therapy trials for MCL and presents the results of innovative regimen, including some integrating novel agents and desintensified chemotherapy.