AHCT Consolidation for Young Mantle Cell Lymphoma Patients?

Undergoing autologous hematopoietic cell transplantation (AHCT) consolidation after induction led to improved progression-free survival (PFS) in a group of younger transplantation-eligible patients with mantle cell lymphoma, according to a retrospective study.

However, there was a lack of improvement in overall survival, which may be a “result of effective salvage therapy after relapse, which may abrogate any improvement on consolidative AHCT after induction,” researcher James N. Gerson, MD, of Fox Chase Cancer Center, and colleagues wrote in The Journal of Clinical Oncology.

Mantle cell lymphoma has no clearly defined standard-of-care first-line treatment strategy, according to the study. There is come benefit of AHCT after induction chemotherapy, but the role of AHCT is unclear in the rituximab era.

In this retrospective study, Gerson and colleagues looked at data from 1,029 patients from 25 medical centers. Patients were aged 65 or younger with newly diagnosed disease from 2000–2015.

With a median follow-up of more than 6 years, the median PFS was 62 months and the median overall survival (OS) was 139 months. Unadjusted analysis showed that transplant was associated with a more than 30-month improvement in PFS compared with no transplant (75 vs 44 months; P < .01). Additionally, there was a significant improvement in OS associated with transplant (147 vs 115 months; P < .05).

On multivariable analysis, the benefit of transplant on PFS remained (HR = 0.54; P < .01), but the benefit on OS was no longer statistically significant (HR = 0.77; P = .06).

The researchers performed a propensity-score weighted (PSW) analysis to guard against inherent bias in retrospective analyses. In the PSW analysis, AHCT was associated with improved PFS (hazard ratio [HR], 0.70; 95% CI, 0.59–0.84; P < .01), but not improved OS (HR, 0.87; 95% CI, 0.69–1.1; P = .2). The lack of improvement in OS in the PSW analysis “raises the possibility that any observed benefits may have resulted from confounding,” the researchers wrote.

“These findings must certainly be interpreted in light of the limitations inherent to the retrospective nature of our study,” they wrote. “AHCT is not a random event, and although we adjusted for confounding, unmeasurable differences between patients may have influenced our findings. Prospective, randomized trials are urgently needed to determine the true benefit of consolidative AHCT.”

Commenting on these results, Professor Simon Rule, University Hospitals Plymouth NHS Trust, said "this population-based study confirms the importance of what is believed to be best practice for our younger patients with mantle cell lymphoma. The use of high-dose cytarabine-based therapy prior to an autologous transplant and the incorporation of rituximab into these treatment regimens is shown to improve outcomes. While it may not be that important what drugs are added to cytarabine, this approach should be our standard of care."