Lenalidomide Consolidation Added to Rituximab Maintenance Therapy in Patients Remaining PET Positive after Treatment for Relapsed Follicular Lymphoma: Phase 2 Australasian Leukaemia & Lymphoma Group NHL26 Study

• Published in: Blood 2021-11, Vol.138 (Supplement 1), p.2428-2428
• Main Authors: Trotman, Judith, Presgrave, Peter, Carradice, Duncan P., Lenton, Douglas Stuart, Gandhi, Maher, Cochrane, Tara, Badoux, Xavier, Nkhoma, Gloria, Butcher, Belinda, Fulham, Michael, Johnston, Anna
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2021-146343

Introduction The combination of rituximab & lenalidomide (R 2) is an established regimen for treatment of follicular lymphoma (FL), with efficacy reported in the first line and relapsed setting (Morchhauser NEJM 2018, Leonard JCO 2019). The inferior OS of patients who remain post-induction PET-CT positive (PET+ve) has also been demonstrated in both settings (Trotman Lancet Haem 2014, Lancet Oncol 2018, Ysebaert, ASH 2011). We sought to study the effect of R 2 in relapsed FL by examining its ability to convert to PET-negative (PET-ve) those patients who remain PET+ve after reinduction rituximab-chemotherapy. Methods This was a prospective, multicentre, Phase 2 study of patients with bulky Stage II, or Stage III-IV relapsed FL. Eligibility criteria were: at least stable disease on CT within 4-6 weeks of last cycle of re-induction rituximab-chemotherapy; ECOG ≤2; CrCL ³30mL/min; haemoglobin >80g/L, neutrophils >1.0 & platelets >75 x 10 9/L. Exclusion criteria were: histological transformation ≤12 months (mo); any interim-PET that was negative, and other malignancy ≤5 years. After enrolment pts underwent a centrally-reviewed PET within 8 weeks of D1 last cycle of re-induction rituximab-chemotherapy. Given the higher probability of further progression in the relapsed setting PET+ve was defined as a Deauville score (DS) 3-5. PET-ve patients were assigned rituximab maintenance q2mo for 2 years, and those remaining PET+ve were assigned R 2 to commence within 12 weeks. Lenalidomide schedule for R 2 pts was 10mg/d x 21 q28d, with dose modifications for tolerance, over a planned 2 years. Repeat PET scans were scheduled at 6 & 12 mo after starting R 2. The primary endpoint was the rate of conversion from postinduction PET+ve to PET-ve in evaluable patients 6 mo after commencing lenalidomide. Evaluable patients were defined as those receiving >63 days of Lenalidomide. Sample size calculations used a one-sided exact test for proportions, assuming a conversion rate of ³50% as worthy of further evaluation and ≤20% as unacceptable. Thus 16 evaluable patients were required to have 80% power with type I error of 5%. Secondary endpoints were PET conversion rates by baseline DS in the PET+ve, the toxicity & deliverability of R 2, and PFS & OS in both the PET+ve & PET-ve populations. Results Thirty-seven patients (pts) were recruited from Nov 2013 to Jan 2021 when the study was closed due to poor recruitment attributed to competing studies. Median (med) age was 67yrs (36-83); 5