Consolidation With ASCT Not Superior to Radioimmunotherapy in Relapsed/Refractory Follicular Lymphoma

In a recent clinical trial in patients with relapsed/refractory (R/R) follicular lymphoma (FL), consolidation using autologous hematopoietic stem cell transplantation (ASCT) was not found to be superior to use of radioimmunotherapy (RIT). Study findings were reported in the journal Annals of Oncology.

The multicenter, randomized, phase 3 FLAZ12 trial (ClinicalTrials.gov Identifier: NCT01827605) enrolled patients with R/R FL who were 18 to 65 years old and who had been treated with chemoimmunotherapy. Patients who reached a partial remission or better were then randomly assigned 1:1 to receive either ASCT or RIT prior to CD34⁺ peripheral blood stem cell collection. 

After consolidation, all participants were given rituximab maintenance. RIT consisted of treatment with rituximab and ⁹⁰Y-ibritumomab tiuxetan. The study had a primary endpoint of progression-free survival (PFS), assessed in the intention-to-treat population.

The study’s target population size was 210 patients, but 159 patients were enrolled, and these patients had a median age of 57 years. Due to low accrual, the study was discontinued prematurely.

A total of 157 patients started induction therapy. Among these patients, following a clinical response with induction, 141 were randomly assigned into the 2 treatment groups, with 70 in the ASCT group and 71 in the RIT group. 

The median study follow-up time was 77 months from enrollment. The estimated 3-year PFS rate in the ASCT group was 62% (95% CI, 49%-73%), and, similarly, in the RIT group it was 62% (95% CI, 49%-72%; hazard ratio [HR], 1.11; 95% CI, 0.69-1.80; P =.6662). Median PFS durations were 62 months in the ASCT group and 78 months in the RIT group.

The 3-year overall survival rates were also similar between treatment groups. In the ASCT group this rate was 87% (95% CI, 76%-93%), and in the RIT group it was 86% (95% CI, 74%-92%; HR, 0.94; 95% CI, 0.45-1.94; P =.8588). Median overall survival times were not reached for either group. 

Event-free survival rates at 3 years were 38% (95% CI, 26%-49%) for the ASCT group and 42% (95% CI, 31%-54%) for the RIT group (HR, 1.19; 95% CI, 0.79-1.80; P =.3963). Median event-free survival times were 23 months in the ASCT group and 25 months in the RIT group. Treatment-free survival rates were also similar between the 2 groups (HR, 1.09; 95% CI, 0.50-2.39; P =.8340).

In safety analysis, grade 3 or 4 hematologic toxicities were reported in 93% of patients evaluated in the ASCT group and in 46% of patients evaluated in the RIT group (P <.0001) during consolidation. Grade 3 or 4 nonhematologic toxicities were reported in 37% of patients evaluated in the ASCT group and in 5% evaluated in the RIT group (P <.0001). 

“The main results of our study do not support any efficacy superiority of ASCT versus radioimmunotherapy and confirm a higher toxicity and clinical complexity with ASCT,” the study investigators wrote in their report.

Disclosures: Some authors have declared affiliations with or received grant support from the pharmaceutical industry. Please refer to the original study for a full list of disclosures.

Reference

Ladetto M, Tavarozzi R, Zanni M, et al. Radioimmunotherapy versus autologous hematopoietic stem cell transplantation in relapsed/refractory follicular lymphoma: a Fondazione Italiana Linfomi multicenter, randomized, phase III trial. Ann Oncol. Published online November 3, 2023. doi:10.1016/j.annonc.2023.10.095

This article originally appeared on Hematology Advisor