Omission of Radiotherapy in Primary Mediastinal B-Cell Lymphoma: IELSG37 Trial Results.

BACKGROUND: The role of consolidation radiotherapy in primary mediastinal B-cell lymphoma (PMBCL) patients is controversial. METHODS: The IELSG37 trial, a randomized non-inferiority study, aimed to assess whether irradiation can be omitted in PMBCL patients with complete metabolic response (CMR) after induction immunochemotherapy. Primary endpoint was progression-free survival (PFS) at 30 months post-randomization. Patients with CMR were randomly assigned to observation or consolidation radiotherapy (30 Gy). With a non-inferiority margin of 10% (assuming a 30-month PFS of 85% in both arms), a sample size of 540 patients was planned with 376 expected to be randomized. RESULTS: The observed events were considerably lower than expected, therefore, primary endpoint analysis was conducted when ≥95% of patients were followed for ≥30 months. Of 545 patients enrolled, 268 were in CMR after induction and were randomized to observation (n=132) or radiotherapy (n=136). The 30-month PFS was 96.2% in the observation arm and 98.5% in the radiotherapy arm, with a stratified hazard ratio of 1.47 (95%CI, 0.34 to 6.28) and absolute risk difference of 0.68% (95%CI, -0.97% to 7.46%). The 5-year overall survival was 99% in both arms.Non-randomized patients were managed according to local policies. Radiotherapy was the only treatment in 86% of those with Deauville score (DS) 4 and in 57% of those with DS 5. The 5-year PFS and OS of patients with DS 4 (95.8% and 97.5%, respectively) were not significantly different from those of randomized patients. Patients with DS5 had significantly poorer 5-year PFS and OS (60.3% and 74.6%, respectively). CONCLUSIONS: This study, the largest randomized trial of radiotherapy in PMBCL, demonstrated favorable outcomes in patients achieving CMR with no survival impairment for those omitting irradiation.

Stem cell collection and hematological recovery in the Fondazione Italiana Linfomi (FIL) MCL0208 clinical trial.

In the frontline high-dose phase 3 FIL-MCL0208 trial (NCT02354313), 8% of enrolled mantle cell lymphoma (MCL) patients could not be randomised to receive lenalidomide (LEN) maintenance vs observation after autologous stem cell transplantation (ASCT) due to inadequate hematological recovery and 52% of those who started LEN, needed a dose reduction due to toxicity. We therefore focused on the role played by CD34 + hematopoietic stem cells (PBSC) harvesting and reinfusion on toxicity and outcome. Overall, 90% (n = 245) of enrolled patients who underwent the first leukapheresis collected ≥ 4 × 106 PBSC/kg, 2.6% (n = 7) mobilized < 4 × 106 PBSC/kg and 7.7% (n = 21) failed the collection. Similar results were obtained for the planned second leukapheresis, with only one patient failing both attempts. Median count of reinfused PBSC was 5 × 106/kg and median time to recovery from neutropenia G4 was 10 days from ASCT. No impact of mobilizing subtype or number of reinfused PBSC on hematological recovery and LEN dose reduction was noted. At a median follow-up of 75 months from ASCT, PFS and OS of transplanted patients were 50% and 73%, respectively. A long lasting G4 neutropenia after ASCT (> 10 days) was associated with a worse outcome, both in terms of PFS and OS. In conclusion, although the harvesting procedures proved feasible for younger MCL patients, long-lasting cytopenia following ASCT remains a significant issue: this can hinder the administration of effective maintenance therapies, potentially increasing the relapse rate and negatively affecting survival outcomes.

End of induction [18F]FDG PET is prognostic for progression-free survival and overall survival in follicular lymphoma patients enrolled in the FOLL12 trial.

PURPOSE: To evaluate the reliability of the Deauville score (DS) in therapy response assessment and to define the prognostic value of the metabolic response of end of induction (EOI) [18F]FDG PET (PET) in follicular lymphoma patients. METHODS: Adult patients with untreated grade 1-3a FL/ stage II-IV enrolled in the multicentre, prospective, phase III FOLL12 trial (NCT02063685) were randomized to receive standard immunochemotherapy followed by rituximab maintenance (standard arm) versus standard immunochemotherapy followed by response-adapted post-induction management (experimental arm). Baseline and EOI PET were mandatory for the study. All PET scans were centralized on the WIDEN® platform and classified according to DS in a blind independent central review. DS1-3 was considered negative (CMR), whereas DS4-5 was considered positive (not CMR). The primary endpoint was PFS. The main secondary endpoint was overall survival (OS). RESULTS: Overall, 807 follicular lymphoma patients-52% women, 89% stage III-IV disease, 40% with a high-risk FLIPI-2 score (3-5)-were enrolled in the study; 729 (90.4%) baseline and EOI PET were available for the analysis. EOI PET was positive (DS4-5) in 88/729 (12.1%) cases. Overall inter-reviewer agreement on PET pos/neg result was 0.92, while agreement on positive and negative cases was 0.77 and 0.94, respectively. The median follow-up was 69 months; 247 events were registered in the 5-yr follow-up, with a 5-yr PFS of 67% (95%CI: 63%-70%). The 5-yr PFS rate for PET neg (DS1-3) and PET pos (DS4-5) patients was 71% (95%CI: 67%-75%) and 36% (95%CI: 25%-46%), respectively, with HR 3.49 (95%CI: 2.57-4.72). Five-year PFS was worse as DS increased, with 74% (70%-78%), 58% (48%-67%; HR 1.71; p = 0.001)] and 36% (25%-46%; HR 3.88; p < 0.001) in DS1-2, DS3 and DS4-5, respectively. EOI PET maintained its prognostic value in both the standard and experimental arms. In the whole population, 5-yr OS was 94% (95%CI: 92%-96%), with 96% (95%CI: 94-97) and 82% (95%CI: 72%-89%) in EOI PET negative (DS1-3) and positive (DS4-5), respectively (HR 4.48; p < 0.001). When DS was associated with FLIPI-2, patients with DS3 or DS1-2 with high FLIPI-2 (3-5) experienced worse OS than patients with DS1-2 and low FLIPI-2 (1-2) (p = 0.003). CONCLUSION: This study shows that DS is a reliable prognostic tool to evaluate EOI PET in follicular lymphoma patients, with prognostic value maintained both in the standard and experimental arms, making metabolic imaging a robust tool to assess response in FL. Moreover, although preliminary, this study provides further information on DS3 patients, who are considered as CMR but show a less favourable PFS than DS1-2 patients.