Evaluating a Response-Adapted Rituximab Approach for Patients With Follicular Lymphoma

In patients with follicular lymphoma (FL), standard rituximab maintenance produced better rates of progression-free survival (PFS) than an experimental response-adopted approach, according to results of the FOLL12 study presented at the 2021 International Conference on Malignant Lymphoma. The findings were shared by lead author Stefano Luminari, MD, from the University of Modena and Reggio Emilia in Italy.

While previous research has shown that two years of rituximab maintenance after first-line rituximab-based chemotherapy significantly improved PFS in this group, the study authors explained that one important question is whether this approach is suitable for all patients.

In this study, researchers randomized patients with treatment-naïve, advanced stage, high tumor burden FL to receive standard rituximab maintenance or a response-adapted rituximab based on metabolic response and molecular assessment of measurable residual disease (MRD). Complete metabolic response at end of induction was defined as a Deauville score of 1-3.

Post-induction therapy in the experimental arm varied according to patient status:

  • complete molecular response (CMR) and MRD negativity: observation
  • CMR and MRD positivity: 4 weekly rituximab doses until reaching MRD negativity, for up to 3 courses
  • no CMR: one dose of ibritumomab tiuxetan followed by standard rituximab maintenance

A total of 712 study participants across both groups achieved at least a partial response at the end of induction. After a median follow-up of 53 months (range = 1-92), patients in the standard arm had significantly higher rates of three-year PFS than those who received the experimental approach: 86% versus 72% (p<0.001).

This finding was confirmed across all response subgroups, the authors added. Rates of three-year PFS in the standard arm versus the experimental arm were:

  • 90% vs. 72% in patients who achieved a CMR (p<0.001)
  • 92% vs. 78% in patients with CMR and MRD negativity (p<0.001)
  • 96% vs. 45% in patients with CMR and MRD positivity (p=0.004)

However, there was no significant difference with either approach in patients without CMR.

At the latest follow-up, 30 patient deaths were reported. Half of these were related to disease progression or recurrence. The three-year rate of overall survival was 98% in the standard arm and 97% in the experimental arm (p=0.238).

Together, the findings of this analysis suggest that a post-induction rituximab strategy according to metabolic and molecular response was associated with a significantly inferior PFS compared to standard two-year rituximab maintenance. “The better efficacy of standard rituximab maintenance was confirmed in the subgroup analysis and in particular for patients achieving both CMR and MRD negativity,” they added.

Study authors report no relevant conflicts of interest.

Reference

Luminari S, Galimberti S, Versari A, et al. Response adapted post induction therapy in follicular lymphoma: updated results of the FOLL12 trial by the Fondazione Italiana Linfomi (FIL). Presented at the 16th International Conference on Malignant Lymphoma, Virtual Edition, June 18-22, 2021.