Long-Term Efficacy and Safety (27 months) of the Biosimilar CT-P10 in Patients with Low Tumor Burden Follicular Lymphoma

We assessed long-term safety and efficacy of CT-P10 and rituximab in patients with newly diagnosed low-tumour-burden follicular lymphoma (LTBFL), and following a single transition from rituximab to CT-P10. This double-blind, parallel-group, active-controlled phase 3 trial randomized patients with CD20+ LTBFL to receive CT-P10 or US-sourced rituximab (375 mg/m2 intravenous). Induction therapy (weekly for 4 cycles) was followed by a 2-year maintenance period for patients achieving disease control (CR, CRu, PR and SD). During the maintenance, CT-P10 or rituximab were administered every 8 weeks (6 cycles) in the first year and additional CT-P10 was administered every 8 weeks (6 cycles) in the second year. Secondary endpoints (reported here) were overall response rate during the study period, progression-free survival, time-to-progression, and overall survival. Safety and immunogenicity were also evaluated over the study period. Between Nov 9, 2015 and Jan 4, 2018, 258 patients were randomised (130 CT-P10; 128 rituximab). Over the study period, 115 (88%; CT-P10) and 111 (87%; rituximab) patients achieved overall response. At a median follow-up of 29·2 months (IQR: 26·1-33·7), median progression-free survival, time-to-progression, and overall survival were not estimable. The KM estimates (95% CI) for OS at 36 months were 98% (93-99) and 97% (89-99) in the CT-P10 and rituximab groups, respectively. Corresponding values for PFS were 80% (70-87) and 68% (54-79), while results for TTP were 82% (72-88) and 68% (54-79) in the CT-P10 and rituximab groups, respectively. (Figure A. OS; Figure B. PFS and Figure C. TTP) Over the study period, 114 (88%) and 104 (81%) patients in the CT-P10 and rituximab groups, respectively, experienced at least one treatment-emergent adverse event (TEAE) and 14 (11%) patients in each group experienced TE-serious adverse events (TESAEs). There were no unexpected safety findings observed during the second year of the maintenance period after single transition from rituximab to CT-P10. [Display omitted] Kwak:Celltrion Healthcare: Membership on an entity's Board of Directors or advisory committees; Xeme Biopharma/Theratest: Other: equity; CJ Healthcare: Consultancy; Sellas Life Sciences Grp: Consultancy; Enzychem Life Sciences: Membership on an entity's Board of Directors or advisory committees; Antigenics: Other: equity; InnoLifes, Inc: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pepromene Bio: Consultanc