Auto HCT and Matched Sibling Transplant Effective in FL

Long-term survival rates were significantly improved after autologous hematopoietic stem cell transplantation (HCT) and allogeneic matched sibling donor HCT in patients with follicular lymphoma with early treatment failure after first-line chemoimmunotherapy, according to the results of a study published in Cancer.

According to the study, transplant is an important treatment option for follicular lymphoma patients, but there is still debate about which transplant approach might be best.

“Our analysis provides vital information for clinical decision making for these high-risk follicular lymphoma patients,” wrote Sonali M. Smith, of the University of Chicago, and colleagues. “Our data support HCT as an appropriate and effective option for transplant-eligible follicular lymphoma patients with early treatment failure because of the noted long-term survival of 70% of patients undergoing either auto-HCT or MSD [genoidentical matched sibling donor] allogeneic HCT.”

In the study, the researchers investigated three transplantation types, auto HCT with matched sibling donor, matched unrelated donor (MUD), or allogeneic HCT (allo-HCT) in patients with high-risk follicular lymphoma with early treatment failure. The 440 participants included patients  18 or older, who had early treatment failure on rituximab-containing chemotherapies, and underwent transplant between 2002 and 2014. The primary endpoint was overall survival (OS).

In all, 240 patients underwent auto-HCT, 105 had matched sibling donor HCT, and 95 had unrelated matched donor HCT.

With a median follow-up of 69 to 73 months, the adjusted 5-year OS was significantly higher after auto-HCT or matched sibling donor HCT compared with matched unrelated donor transplant (70% and 73% vs 49%; P = .008).

The 5-year adjusted probability of non-relapse mortality (NRM) was significantly lower in patients who underwent auto-HCT (5%) compared with matched sibling donor (17%) or MUD transplant (33%; P < .0001). The researchers noted that this outcome was “somewhat unexpected."

“This finding is in contrast to other studies showing similar OS with MSD and MUD allo-HCT for follicular lymphoma ,” the researchers wrote. “The more frequent use of anti-thymocyte globulin or alemtuzumab in the MUD cohort versus the MSD cohort could be a possible explanation.”

The likelihood of relapse or progression at 5 years was significantly higher in patients in the auto-HCT group (58%) compared with matched sibling donor (31%) or matched unrelated donor groups (23%; P < .0001). However, during the first 7 months after transplant the risk of relapse or progression was similar between the three groups. After7 months, there was a lower risk in the matching sibling and matched unrelated groups.

“A major clinical challenge for patients with relapsed follicular lymphoma undergoing HCT is the selection between autologous and allogeneic approaches,” the researchers wrote. “Similarly to other registry analyses, patients undergoing allo-HCT had higher risk disease with more lines of prior therapy, had more advanced-stage disease, and more frequently had chemorefractoriness at the time of transplantation. The observation of significantly lower 5-year relapse rates in the 2 allo-HCT cohorts despite these adverse features is noteworthy and demonstrates that potent graft-versus lymphoma effects are operational even in the highest risk FL patients.”