Chimeric antigen receptor (CAR) T-cell treatment for mantle cell lymphoma (MCL)

Mantle cell lymphoma (MCL) is a rare B-cell malignancy that remains challenging to treat with high rates of relapse. Frontline strategies range from intensive chemotherapy followed by consolidation with autologous stem cell transplant (ASCT), to less-intensive therapies including combination regimens. The treatment landscape for relapsed patients includes Bruton tyrosine kinase (BTK) inhibitors among other targeted treatments. Novel agents such as the selective BCL2 inhibitor venetoclax showed high response rates when used as monotherapy for refractory relapsed MCL. The rituximab, bendamustine, and cytarabine (R-BAC) regimen, while response rates were high, were not durable. Chimeric antigen receptor (CAR) T-cell products targeting CD19 have been efficacious in relapsed and refractory MCL patients. Brexucabtagene autoleucel (brexu-cel, formerly KTE-X19) was approved by US Food and Drug Administration (FDA) in July, 2020, for treatment of refractory and relapsed MCL. This article provides an overview for the available management strategies for relapsed MCL and examines the role of CAR T-cell in the current and future treatment of MCL.

The impact of socioeconomic disparities on the use of upfront autologous stem cell transplantation for mantle cell lymphoma

Using the National Cancer Database, we identified 10,290 patients with newly diagnosed mantle cell lymphoma (MCL) treated with chemotherapy with or without upfront autologous stem cell transplantation (ASCT). Only 17% of patients underwent ASCT. Patients who underwent ASCT were younger and more likely to have lower comorbidity scores, private insurance, higher income and education, and treatment received at an academic facility. On multivariable analysis, age, comorbidity index, insurance type, the transition of care, facility type, distance to facility, and diagnosis year were predictive for ASCT use. ASCT use was associated with improved 5-year overall survival in younger (82% vs. 64%, p < .001) and older (70% vs. 40%, p < .001) patients, which was retained in the matched propensity score and 12-month analyses. Female gender, the diagnosis year ≥2009, private insurance, higher income, and education were associated with superior survival, whereas Black race and higher comorbidities predicted inferior survival.

Bortezomib in the treatment of mantle cell lymphoma

Mantle cell lymphoma (MCL) is a hematological malignancy with unfavorable prognosis. Bortezomib, a potent, selective and reversible inhibitor of the 26S proteasome, was shown to be active in MCL and is currently implemented in therapeutic combinations. Single-agent bortezomib has demonstrated clinical efficacy in relapsed and refractory MCL with objective response in up to 47% of the patients. However, complete remission rates are low and duration of response is relatively short. In previously untreated patients, the addition of bortezomib to induction chemotherapy is also promising. Further evaluation of bortezomib alone or in combination with other drugs for the treatment of MCL is warranted to improve the quality of life and survival of patients. This review explores bortezomib as therapy in patients with MCL.

Development of the Bruton's tyrosine kinase inhibitor ibrutinib for B cell malignancies

Ibrutinib is a first-in-class oral covalent inhibitor of Bruton's tyrosine kinase that has demonstrated clinical benefit for many patients with B cell malignancies. Positive results in initial trials led the U.S. Food and Drug Administration to grant ibrutinib three breakthrough therapy designations for mantle cell lymphoma (MCL), del17p chronic lymphocytic leukemia (CLL), and Waldenström's macroglobulinemia (WM). Ibrutinib was approved for these three cancers within 14 months of the original U.S. approval. Additionally, ibrutinib is approved for patient subsets with MCL and/or CLL in >45 other countries. Via a unique mechanism of action, ibrutinib inhibits B cell signaling pathways that regulate the survival, proliferation, adhesion, and homing of cancerous cells. This marks a paradigm shift from the conventional cytotoxic chemotherapy approach to treating B cell malignancies. Ibrutinib continues to be evaluated across a range of B cell malignancies, either as single-agent therapy or in combination with other therapies, and continues to transform the lives of these patients.

Do mantle cell lymphomas have an 'Achilles heel'?

PURPOSE OF REVIEW

Mantle cell lymphoma (MCL) is a mature B-cell malignancy that continues to have a high mortality rate. In this article, we discuss key pathogenic pathways in MCL biology and their possible therapeutic targeting.

RECENT FINDINGS

In addition to cyclin-D1, the transcription factor SOX-11 emerged as a common characteristic of MCL. Genomic studies have identified a number of recurrently mutated genes; in order of descending frequency these include ATM, CCND1, UBR5, TP53, BIRC3, NOTCH1/2 and TRAF2. However, no clear oncogenic driver has been identified. In contrast, several observations indicate that MCL cells are antigen-experienced cells and that the tumor microenvironment and B-cell receptor engagement are important. This is underscored by the impressive clinical responses achieved with the Bruton's tyrosine kinase inhibitor ibrutinib. Recently identified activating mutations in the noncanonical nuclear factor-kappa B pathway could give rise to ibrutinib resistance. Poly-ADP ribose polymerase and aurora kinase inhibitors may be synthetic lethal with the common aberrations in DNA damage pathways found in MCL. Also, ABT-199, a potent and selective inhibitor of B-cell lymphoma 2, has promising activity in early studies.

SUMMARY

MCL is a heterogeneous disease, and no single Achilles heel has been identified. Nevertheless, genomic, molecular and clinical studies have revealed vulnerabilities that can be exploited for effective therapy.