In older patients with newly diagnosed mantle cell lymphoma (MCL), first-line therapy with rituximab- and bendamustine-based regimens significantly reduced 1-year mortality rates versus chemotherapy alone, according to a retrospective analysis.
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Mantle cell lymphoma
“This study evaluated the comparative effectiveness of [rituximab, bortezomib, or bendamustine] in elderly patients newly diagnosed with MCL,” wrote Shuangshuang Fu, PhD, of the University of Texas MD Anderson Cancer Center, Houston, and colleagues. The findings were reported in Clinical Lymphoma, Myeloma & Leukemia.
The researchers studied population-based data from the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database. They identified all patients over age 65 years who received a new diagnosis of MCL between Jan. 1, 1999, and Dec. 31, 2013.
The study cohort included a total of 1,215 patients. Participants were classified into four different groups according to treatment regimen: chemotherapy alone, rituximab plus or minus chemotherapy, bendamustine plus or minus chemotherapy, and bortezomib plus or minus chemotherapy.
At 1-year follow-up, the team analyzed various mortality outcomes, including MCL-specific, all-cause, and noncancer mortality. The bortezomib results were not included in the primary analysis because of small sample size, according to the researchers.
After multivariable analysis, Dr. Fu and colleagues found that 1-year all-cause mortality rate was significantly lower for patients receiving rituximab-based regimens, compared with chemotherapy alone (hazard ratio, 0.38; 95% confidence interval, 0.25-0.59). There was a similar decline for MCL-specific mortality (HR, 0.38; 95% CI, 0.24-0.60).
The 1-year MCL-specific mortality was also significantly reduced in the bendamustine group, compared with chemotherapy alone (HR, 0.49; 95% CI, 0.24-0.99).
“Our findings comparing rituximab with chemotherapy alone further confirmed the benefit of adding rituximab to chemotherapy in newly diagnosed older MCL patients,” they wrote.
The researchers acknowledged that a key limitation of the study was the observational design. As a result, selection bias and unmeasured confounding could have influenced the results.
“Future studies evaluating the comparative effectiveness of those newly approved novel agents for MCL patients were warranted as more data are available,” they concluded.
The study was funded by the Duncan Family Institute, the Cancer Prevention Research Institute of Texas, and the National Institutes of Health. The authors reported having no conflicts of interest.
SOURCE: Fu S et al. Clin Lymphoma Myeloma Leuk. 2019 Aug 30. doi: 10.1016/j.clml.2019.08.014.