Correspondence published on 30-January 2018 in the British Journal of Haematology by Liam Smyth et al described their phase II study on the use of interferon-alpha (IFN-α) and rituximab (R) maintenance after autologous stem cell transplant (ASCT) in relapsed/refractory (R/R) follicular lymphoma (FL). Following evidence from a meta-analysis that supported the use of IFN-α in FL, the authors aimed to assess survival outcomes and minimal residual disease (MRD) in patients using this combination of immunotherapy and high dose therapy (HDT).
The treatment protocol involved salvage therapy followed by an in vivo purge with rituximab, and eligible patients then received HDT. Thirty patients (median age = 47 years) were successfully transplanted and treated with R-maintenance with 27 patients receiving IFN-α. Ten of these patients discontinued early whilst 17 patients completed two years of IFN-α with a complete response (CR) rate of 77%.
The median follow-up of this study was 10.3 years, range 1.9–16.2. The median overall survival (OS) was not reached (range = 3.6–16.2 years) and the authors observed a “survival plateau” at 8 years. The median progression-free survival (PFS) was also not reached, range 0.7–15.2 years. The authors found that the remission duration pre-enrolment and secondary malignancy development were factors that significantly affected OS in both univariate and multivariate analysis. MRD was detected using real-time quantitative polymerase chain reaction (PCR) in 22 patients with ten samples showing detectable disease. The authors noted that the difference in PFS was not significantly different in patients who were either MRD positive or negative suggesting that the study regimen was effective at “eradicating residual disease”.
The authors concluded that the positive results from this study demonstrated good survival outcomes with the combination of rituximab, INF-α and ASCT.