Survival Benefit of Autologous HSCT in Mantle Cell Lymphoma Confirmed in Post Hoc Analysis

Investigators have confirmed the long-term survival benefit provided by autologous hematopoietic stem-cell transplantation (HSCT) over interferon alfa maintenance therapy in the treatment of patients with previously untreated mantle cell lymphoma (MCL), according to the results of a post hoc analysis of a phase 3 trial.

The significant progression-free survival (PFS) advantage for patients in the autologous HSCT group was confirmed via the formal overrunning analysis, which corrected for sequential design (corrected P = .0088). In the exploratory intention-to-treat analysis, the median progression-free survival (PFS) was 3.3 years (95% CI, 2.5-4.3) for patients receiving autologous HSCT compared with 1.5 years (95% CI, 1.2-2.0) for patients receiving interferon alfa (; HR, 0.50; 95% CI, 0.36-0.69; P< .0001).

“With this longer follow-up, we reported a significant improvement in the median [PFS] after clinical remission and in median overall survival [OS] after autologous HSCT,” the investigators wrote. “These data underline the value of autologous HSCT-containing treatment strategies in the first-line setting, which is the current recommended standard of care in young patients in Europe.”

Patients who were included on the trial were randomly assigned to receive either autologous HSCT (n = 134) or interferon alfa maintenance therapy (n = 135) between September 30, 1996, and July 1, 2004. The intention-to-treat population included 174 patients, including 81 patients in the interferon alfa group and 93 patients in the autologous HSCT group. The median age of the patient population was 55 years (IQR, 47-60). Fifty-one percent of patient were treated with clophosphamide, doxorubicin hydrochloride, vincristine sulfate, and prednisone (CHOP) and rituximab (Rituxan) plus CHOP was used in 39% of patients. The median follow-up time was 14 years.

Eligible patients were between the ages of 18 and 65 years and had been diagnosed with previously untreated advanced stage III and IV MCL. Additionally, patients were required to have an ECOG performance status of 0 to 2. The primary end point for this analysis was PFS, with overall survival (OS) acting as a key secondary end point.

Patients in partial or complete remission after induction therapy who received autologous HSCT had a median OS of 7.5 years (95% CI 5.7-12.0) compared with 4.8 years (95% CI, 4.0-6.6) for patients who received interferon alfa (adjusted HR, 0.66; 95% CI, 0.46-0.95; P = .019).

After examining the cohort of patients who were treated without rituximab, investigators reported a median PFS of 3.1 years (95% CI, 2.5-4.3) for patients in the autologous HSCT group compared with 1.2 years (95% CI, 1.0-1.9) in the interferon alfa maintenance group (P < .0001). The median OS for the analysis was 6.7 year (95% CI 5∙4–12∙9) and 4.3 years (95% CI, 3.6-6.6) for patients in the autologous HSCT interferon alfa maintenance groups, respectively (P = .016).

“Whether an autologous HSCT should be generally recommended despite the available additional therapeutic options cannot be appropriately addressed with this trial alone. However, the absence of any significant benefit of autologous HSCT for patients after rituximab-containing induction underlines the need to further explore the value of autologous HSCT in comparison with the most effective regimens available,” the investigators concluded.

Reference

Zoellner AK, Unterhalt M, Stilgenbauer S, et al. Long-term survival of patients with mantle cell lymphoma after autologous haematopoietic stem-cell transplantation in first remission: a post-hoc analysis of an open-label, multicentre, randomised, phase 3 trial. Lancet Haematol. 2021;8(9):e648-e657. doi:10.1016/S2352-3026(21)00195-2