CLINICAL OUTCOMES IN PATIENTS RELAPSED/REFRACTORY AFTER ≥ 2 PRIOR LINES OF THERAPY FOR FOLLICULAR LYMPHOMA: A SYSTEMATIC LITERATURE REVIEW AND META‐ANALYSIS

Abstract

Introduction: Patients with follicular lymphoma (FL) can have high response rates to early lines of treatment. However, among FL patients relapsed/refractory (r/r) after ≥2 prior lines of therapies (LOT), remission tends to be shorter and there is limited treatment guidance. This study sought to evaluate the clinical outcomes for r/r FL after ≥2 prior LOT using available treatment options. Methods: Electronic databases were searched on 2nd June 2020. Eligible studies were comparative or non-comparative interventional or observational studies of systemic therapies among adults with FL r/r after ≥2 prior LOT. Prior LOT must have included anti-CD20 monoclonal antibodies and alkylating agents, in combination or separately. Overall response rate (ORR) and complete response (CR) were analyzed using inverse-variance weighting with Freeman-Tukey double-arcsine transformations. Kaplan-Meier (KM) analysis for progression-free survival (PFS) and overall survival (OS) were conducted using digitized curves and the Guyot algorithm. Survival analyses were stratified by ≥2 prior LOT and ≥3 prior LOT groups and were restricted to the observational cohorts as a sensitivity analysis. Results: The meta-analysis included 12 studies published from 2014-2020. Sample size for response outcomes was 340, for survival outcomes with ≥2 prior LOT was 1024 and for ≥3 prior LOT was 502. The estimated ORR in the ≥2 prior LOT group was 56.0% (95% confidence interval [CI]: 47.2 – 64.5) and proportion of patients with CR was 12.2% (95% CI: 8.0 – 17.3). The median OS was 54.4 months (95% CI: 45.8 – 76.0) and median PFS was 10.3 months (95% CI: 9.3 – 11.1). The 24-month OS decreased from 66% in the ≥2 prior LOT group to 60% in the ≥3 prior LOT group (Table 1), with a similar trend in PFS at 24-month (28% vs 24%). Conclusions: This study found that few r/r FL patients with ≥2 prior LOT achieve CR, and despite some benefit, approximately 1/3 of patients die within 24 months. The shorter median PFS with increasing prior LOT suggest treatment durability is suboptimal in later LOT. These findings indicate that patients are underserved by current treatments, demonstrating a need for new treatments that can achieve high rates of durable response in this disease. EA – previously submitted to ASCO and EHA 2021. The research was funded by: This project was funded by Kite, a Gilead company. Keywords: Indolent non-Hodgkin lymphoma Conflicts of interests pertinent to the abstract S. Kanters Employment or leadership position: RainCity Analytics Research funding: RainCity Analytics has received funds from for-profit healthcare companies for research B. Kahl Consultant or advisory role: Abbvie, Acerta, AstraZeneca, Celege, Kite, Genentech, Pharmacyclics, MEI Research funding: Genentech, Celgene, Acerta, AstraZeneca A. Wiesinger Employment or leadership position: Kite, A Gilead Company Stock ownership: Kite, A Gilead Company B. Gurung Employment or leadership position: IQVIA Ltd Research funding: IQVIA Ltd E. H Limbrick-Oldfield Employment or leadership position: RainCity Analytics A. Sudhindra Employment or leadership position: Atara Biotherapeutics, Kite Pharma Stock ownership: Atara Biotherapeutics, Gilead J. Thornton Snider Employment or leadership position: Kite, A Gilead Company Stock ownership: Gilead Sciences Research funding: Previously employed at PrecisionHEOR, which receives research funding from life sciences companies. A. R Patel Employment or leadership position: Kite, A Gilead Company Stock ownership: Kite, A Gilead Company