Immune priming with nivolumab followed by nivolumab and rituximab in first-line treatment of follicular lymphoma: The phase 2 1st FLOR study.
Authors: Eliza Anne Hawkes, Sze Ting Lee, Geoff Chong, Michael Gilbertson, Andrew Grigg, Leonid Churilov, Tineke Fancourt, Colm Keane, David Ritchie, Rachel Koldej, Rishu Agarwal, Kate Manos, Charmaine Smith, Kristen Houdyk, Joanne Hawking, Allison Barraclough
Journal: Journal of Clinical Oncology (2021)

7560 Background: Standard of care immunochemotherapy in front-line (1L) follicular lymphoma (FL) is highly efficacious but not without significant toxicity. High rates of grade 3-5 adverse events (AEs), primarily infection and bone marrow suppression, are experienced in up to 75% of patients. A more tolerable but equally effective approach is required. PD-1 inhibition, in combination with rituximab (R), increases T cell anti-tumour effect &amp; enhances NK cell antibody dependent cell cytotoxicity, with proven efficacy in relapsed FL. The concept of ‘priming’ the immune system with nivolumab (N) prior to tumour-directed therapy has rationale and evidence, but the safety of this approach in 1L FL is not described. Methods: ‘1 st FLOR’ (NCT03245021) is an open-label, multi-centre, phase 2, Simon’s 2-stage study of N + R (N = 39). Key eligibility were stage III-IV grade 1-3A FL requiring 1L systemic therapy; ECOG ≤2; adequate organ function. All patients (pts) receive induction N 240mg IV 2-weekly for 4 cycles. Pts with complete response (CR) receive 4 further cycles of 240mg IV N monotherapy then 12 cycles of maintenance N 480mg IV 4-weekly. Pts with &lt; CR had 240mg N plus 375mg/m 2 IV R 2-weekly for 4 cycles followed by maintenance N+R (N 480mg 4 weekly for 12 cycles; R 12 weekly for 8 cycles). Primary endpoint (EP) was ≥ G3 toxicity rate during induction. Secondary EPs; response rate by Lugano response criteria, overall toxicity, PFS, OS. Results: Between September 2017 to March 2020, 39 pts were enrolled. Baseline characteristics included median age of 54 (range: 28-79). stage IV disease in 67%, B Symptoms &amp; bulk (≥7cm) in 23% each, intermediate-high risk FLIPI in 74%. The primary EP was met, with only 16 pts (41%) having ≥G3 toxicity at end of induction. Non-immune AEs were predominantly G1-2; most commonly infection (67%) &amp; fatigue (64%). G3-4 Immune-related AEs were infrequent and included pancreatitis plus hepatitis (N = 1), pancreatitis alone (N = 1), rash (N = 1), transaminitis (N = 2), hypocortisolism (N = 1), hyperglycaemia (N = 3) and asymptomatic lipase/amylase increase (N = 3). Median follow-up was 17.5 months (range: 7-39). Overall response rate was 92% (36/39) with CR in 54% (21/39). Median time to CR was 5 months (m) (range: 2-25). Nine pts (23%) discontinued treatment; 7 due to progressive disease (1 pt died of transformed FL), 2 developed constitutional symptoms (1 stable disease, 1 partial response). In 25 evaluable pts, 12m PFS &amp; OS is 72% (CI 51-88) &amp; 96% (CI 80-100). Biomarker analysis is in progress. Conclusions: Immune-priming with single-agent N, then combination N+R in 1L FL is associated with favourable toxicity and high ORR &amp; CR rates potentially providing an alternative to chemotherapy. Acknowledgements: Bristol-myers Squibb provided funding and nivolumab for this study. Clinical trial information: NCT03245021.