What are the outcomes of reduced intensity alloSCT in MCL patients?

This study investigated the long-term outcomes of MCL (mantle cell lymphoma) patients who received RIST (reduced-intensity allogenic stem cell transplant) therapy. The authors concluded that RIST may be curative in MCL patients, even in those who relapsed after autoSCT (autologous stem cell transplant).

Mantle cell lymphoma (MCL) is an uncommon type of non-Hodgkin’s lymphoma (NHL). MCL has been associated with disease that does not respond to chemotherapy. As a result, these patients tend to have a poor prognosis. The current standard of first-line care is intense therapy with cytarabine (Cytosar-U) and rituximab (Rituxan), followed by autoSCT. However, most patients relapse after treatment, and need alternative therapies.

Allogeneic stem cell transplantation (alloSCT) is one alternative therapy. Most MCL patients are not eligible for this therapy due to age or other health conditions. RIST therapy is an option for these patients, but the side effects and outcomes of this treatment are controversial.

This study involved 324 patients with MCL. 60% of patients had three or more therapies before RIST treatment, such as autoSCT (46%). 66% of patients had stage 3 or 4 disease. 27% of patients had refractory (did not respond to treatment) disease. The average follow-up period was 6 years.

At follow-up, 36% of patients relapsed or had disease progression. The relapse rate at 5 years post-transplant was 40%. Rituximab treatment pre-transplant decreased risk of relapse by 44%. Progression-free survival (time from treatment before disease progression) at 4 years was 31%. Overall survival (time from treatment to death of any cause) at 4 years was 40%.

100 days post-transplant, 52% of patients experienced acute GHVD (graft-versus-host disease, when the transplanted cells attack healthy tissue). 81% of patients were at risk for chronic GHVD. Of these, 43% experienced it. 1 year post-transplant, 41% of patients reported chronic GHVD. T-cell depleting treatment pre-transplant reduced the risk of acute GHVD by 54% but increased risk of relapse 2.59-fold.

1 year post-transplant, the mortality rate due to GHVD and/or infection was 24%. 30% of patients died at 4.5 months post-transplant, with 87% due to GHVD and/or infection. However, use of ATG/ALG treatment before the transplant decreased mortality risk by 41%.

This study concluded that RIST may be curative in MCL patients, even in those who relapse after an autologous stem cell transplant.

This study enrolled 795 patients, but only 324 were included in the data analysis. Only transplants done before 2008 were analyzed, so these results may be different from those of patients receiving current standards of treatment. Lastly, this study looked back in time to analyze data. As a result, the collected data may be incomplete. More research is needed to compare RIST to autoSCT for high-risk patients, and to explore combinations of RIST with other therapies.

If you have relapsed MCL after an autologous stem cell transplant, discuss the potential benefits of RIST therapy with your care team.