Clinical management of mantle cell lymphoma in the elderly

PRMT5 inhibition drives therapeutic vulnerability to combination treatment with BCL-2 inhibition in mantle cell lymphoma

Mantle cell lymphoma (MCL) is an incurable B-cell malignancy that comprises up to 6% of non-Hodgkin lymphomas diagnosed annually and is associated with a poor prognosis. The average overall survival of patients with MCL is 5 years, and for most patients who progress on targeted agents, survival remains at a dismal 3 to 8 months. There is a major unmet need to identify new therapeutic approaches that are well tolerated to improve treatment outcomes and quality of life. The protein arginine methyltransferase 5 (PRMT5) enzyme is overexpressed in MCL and promotes growth and survival. Inhibition of PRMT5 drives antitumor activity in MCL cell lines and preclinical murine models. PRMT5 inhibition reduced the activity of prosurvival AKT signaling, which led to the nuclear translocation of FOXO1 and modulation of its transcriptional activity. Chromatin immunoprecipitation and sequencing identified multiple proapoptotic BCL-2 family members as FOXO1-bound genomic loci. We identified BAX as a direct transcriptional target of FOXO1 and demonstrated its critical role in the synergy observed between the selective PRMT5 inhibitor, PRT382, and the BCL-2 inhibitor, venetoclax. Single-agent and combination treatments were performed in 9 MCL lines. Loewe synergy scores showed significant levels of synergy in most MCL lines tested. Preclinical, in vivo evaluation of this strategy in multiple MCL models showed therapeutic synergy with combination venetoclax/PRT382 treatment with an increased survival advantage in 2 patient-derived xenograft models (P ≤ .0001, P ≤ .0001). Our results provide mechanistic rationale for the combination of PRMT5 inhibition and venetoclax to treat patients with MCL.

Clinical characteristics and outcomes among 2347 patients aged ≥85 years with major lymphoma subtypes: a Nordic Lymphoma Group study

There is a lack of data regarding treatment and prognosis for the growing group of oldest old patients with lymphoma. Therefore, we studied 2347 patients aged ≥85 years from the Danish and Swedish lymphoma registers 2000–2016 (Denmark) and 2007–2013 (Sweden). Outcome was assessed using relative survival (RS). The 2‐year RS overall for patients with aggressive lymphomas was 38% [95% confidence interval (CI) 35–42%], of whom 845 (66%) patients received active treatment (chemotherapy, radiotherapy, immunotherapy, other). For aggressive lymphomas, not receiving active treatment was associated with an inferior 2‐year RS of 12% (95% CI 9–17%) compared to 49% (95% CI 45–53%) for patients who received active treatment (excess mortality rate ratio 2·84, 95% CI 2·3–3·5; P < 0·0001). For patients with indolent lymphoma, the 2‐year RS was 77% (95% CI 72–82%). Here, 383 (46%) patients received active treatment at diagnosis, but did not have better 2‐year RS (75%, 95% CI 67–81%) compared to those who did not receive active treatment (83%, 95% CI 74–89%). We conclude that outcomes for the oldest old patients with lymphoma are encouraging for several subtypes and that active treatment is associated with improved outcome amongst the oldest old patients with aggressive lymphomas, indicating that age itself should not be a contraindication to treatment.

Advances in the assessment of minimal residual disease in mantle cell lymphoma

The clinical impact of minimal residual disease detection at early time points or during follow-ups has been shown to accurately predict relapses among patients with lymphomas, mainly in follicular and diffuse large B cell lymphoma. The field of minimal residual disease testing in mantle cell lymphoma is still evolving but has great impact in determining the prognosis. Flow cytometry and polymerase chain reaction-based testing are most commonly used methods in practice; however, these methods are not sensitive enough to detect the dynamic changes that underline lymphoma progression. Newer methods using next-generation sequencing, such as ClonoSeq, are being incorporated in clinical trials. Other techniques under evolution include CAPP-seq and anchored multiplex polymerase chain reaction-based methods. This review article aims to provide a comprehensive update on the status of minimal residual disease detection and its prognostic effect in mantle cell patients. The role of circulating tumor DNA-based minimal residual disease detection in lymphomas is also discussed.