Rituximab maintenance may mitigate differences in survival between younger and older patients with mantle cell lymphoma (MCL), according to research published in the American Journal of Hematology.
Researchers undertook a retrospective study to assess practice patterns, clinical outcomes, and predictors of relapse and survival in patients with MCL, comparing older patients (65 years and older) with younger patients (younger than 65 years).
The study included 1162 patients with newly diagnosed MCL who were treated from 2000 to 2015 at 12 US academic centers. This time period was chosen to “account for more conventional use of rituximab,” according to the researchers.
Of the 1162 patients, 697 were in the younger age group, and 465 were in the older age group. The median follow-up was 4 years for the younger cohort and 2.7 years for the older cohort.
The 1-year progression-free survival (PFS) rate was 88.7% for the younger group and 82.4% for the older group. The 2-year PFS rate was 78.6% and 67.1%, respectively (P <.001).
The 1-year overall survival (OS) rate was 96.8% in the younger group and 92.7% in the older group. The 2-year OS rate was 92.1% and 85.5%, respectively (P <.001).
In a multivariate analysis, rituximab maintenance was significantly associated with improved OS in younger and older patients (P <.001 for both). High-dose cytarabine induction was associated with a trend toward improved OS among older patients (P =.065).
“[S]urvival outcomes for older patients remain inferior to those of younger patients in the rituximab era,” the researchers wrote. “However, maintenance rituximab and potentially high-dose cytarabine-based induction can mitigate the negative impact of age on survival.”
The researchers noted that, regardless of age group, patients with early relapse or primary refractory disease had “dismal OS.” In this group, worse OS was associated with blastoid histology (P <.001) and Ki-67 above 30% (P <.001-.004).
There were no correlations between chemotherapy resistance and other high-risk features, such as the presence of TP53 mutations and/or complex karyotype (defined as more than 3 cytogenetic abnormalities).
There was no survival benefit of autologous hematopoietic cell transplant (AHCT), compared with rituximab maintenance alone, in either age group.
“Use of maintenance rituximab appears to have the greatest impact on survival in older patients, while the utility of high-dose cytarabine and/or AHCT remains less clear across all age groups,” the researchers wrote. “Focused clinical trials are necessary to identify more effective induction regimens that achieve durable responses and should incorporate maintenance strategies in the older patients.”
Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
Karmali R, Switchenko JM, Goyal S, et al. Multi-center analysis of practice patterns and outcomes of younger and older patients with mantle cell lymphoma in the rituximab era. Am J Hematol. Published online July 29, 2021. doi:10.1002/ajh.26306