Long Term Follow-up of the GELF86 French and Belgian Trials: Complete Remission after First Line Treatment with Conventional Chemotherapy in Newly Diagnosed Follicular Lymphoma Patients Correlates with Prolonged Overall Survival Compared with Partial Remission
Authors: Bachy E. , Brice P. , Fournier M. , Tilly H. , Haioun C. , Brousse N. , Le Gouil S. , Bosly A. , Coiffier B. , Gisselbrecht C. , Solal-Celigny P. , Salles G. 
Published: April 2020

Abstract
Purpose . Frontline treatment for newly diagnosed follicular lymphoma (FL) patients, ranging from watch and wait policy to high-dose therapy, still remains debated, even in the rituximab-based combination therapy era. Few studies have addressed the question whether complete remission (CR) translates into better survival compared to partial remission (PR). The aim of this study was to assess the potential correlation between response quality to first line treatment and overall survival in light of a long-term follow-up.
Patients and methods. Data from 536 FL patients, 435 enrolled in the French and Belgian GELF86 trials and 101 additional patients treated with the same chemotherapy regimen (CHVP-IFN or CHVP regimen after the accrual stopping date with prospectively collected data), were analysed in the study. Data from the GELF86 trials have been previously reported: 193 patients had low tumor burden (LTB) (Brice et al., JCO, 1997) and 242 and the aforementioned 101 additional patients had high tumor burden (HTB) at diagnosis (Solal-Céligny et al., NEJM 1993). All patients with at least one criteria for HTB were treated as frontline therapy with an anthracycline based CHVP regimen: cyclophosphamide, doxorubicin, teniposide, and prednisone monthly for 6 months and then every 2 months for 1 more year. Patients were randomly assigned to the CHVP arm (n=153) or the CHVP-IFN arm (n=190) when they also received α-interferon three times weekly for 18 months. Patients with LTB FL were randomly assigned to one of the three arms: arm 1, no initial treatment (n=66); arm 2, prednimustine for 5 days per month for 18 months (n=64); or arm 3, IFN three times per week for 15 months (n=63).
Results. Median follow-up was 14.3 years and median overall survival (OS) was 9.8 years for the whole cohort. As expected, the Follicular Lymphoma International Prognostic Index (FLIPI) was a strong prognostic factor as well as bone marrow involvement, erythrocyte sedimentation rate (ESR), and B symptoms in univariate analysis or the FLIPI, lymphocytes count, ESR and male sex in multivariate analysis, respectively. Furthermore, treated patients who achieved a CR (n=170, 40%) had a significant longer OS than those only reaching a PR (n=162, 38%) throughout treatment (10-year OS was 64% (95% CI, 57–71%) for CR patients and 46% (95% CI, 38–54%) for PR patients, logrank p=0.0002). In a subgroup analysis by tumour burden, CR remained highly predictive of a better outcome for HTB patients (logrank p=0.001) but not for LTB patients. No difference was observed between patients who went into early complete remission (≤ 6 months) versus late complete remission (&gt; 6 months). Finally, when only HTB patients receiving CHVP-IFN were compared with those receiving the same treatment in the FL2000 trial (Salles et al., Blood, in press), Cox analysis adjusted for the FLIPI indicated a better outcome for FL2000 patients (HR=0.66, 95% CI 0.44–0.99, p=0.047).
Conclusion. These data provide a long follow-up of these patients’ cohorts, and indicate strong evidence that better response to first line treatment translates into a favorable outcome for patients with newly diagnosed FL, especially for HTB patients.