ImportanceAflibercept biosimilars can expand available treatment options in retinal diseases and have the potential to improve patient access to safe and effective therapy.ObjectiveTo establish equivalence in efficacy and similarity in safety, pharmacokinetics, and immunogenicity of SB15 and reference aflibercept (AFL) in neovascular age-related macular degeneration (nAMD).Design, Setting, and ParticipantsThis was a randomized double-masked parallel group phase 3 trial conducted at 56 centers in 10 countries from June 2020 to March 2022, including follow-up through 56 weeks. Of 549 screened participants, 449 participants 50 years and older with treatment-naive nAMD were included and randomly assigned to SB15 (n = 224) or AFL (n = 225). Key exclusion criteria included considerable scarring, fibrosis, atrophy, and hemorrhage. This report includes results up to the end of the parallel group period at week 32. Of the 449 randomized participants, 438 (97.6%) completed week 32 follow-up.InterventionParticipants were randomized 1:1 to receive 2 mg of SB15 or AFL every 4 weeks for the first 12 weeks (3 injections), followed by dosing every 8 weeks up to week 48, with final assessments at week 56.Main Outcomes and MeasuresThe primary end point was the change in best-corrected visual acuity (BCVA) from baseline to week 8 with predefined equivalence margins of −3 letters to 3 letters. Other key end points were changes in BCVA and central subfield thickness up to week 32, safety, pharmacokinetics, and immunogenicity.ResultsThe mean (SD) age among the 449 included participants was 74.0 (8.1) years, and 250 participants (55.7%) were female. Baseline demographic characteristics and most disease characteristics were comparable between treatment groups. The least squares mean change in BCVA from baseline to week 8 in the SB15 group was equivalent to that in the AFL group (6.7 letters vs 6.6 letters, respectively; difference, 0.1 letters; 95% CI, −1.3 to 1.4). Comparable efficacy between treatment groups was maintained up to week 32 (least squares mean change from baseline in BCVA: SB15, 7.6 letters vs AFL, 6.5 letters; least squares mean change from baseline in central subfield thickness: SB15, −110.4 μm vs AFL, −115.7 μm). No clinically relevant differences were observed in the incidence of treatment-emergent adverse events (TEAEs) (SB15, 107/224 [47.8%] vs AFL, 98/224 [43.8%]) and ocular TEAEs in the study eye (SB15, 41/224 [18.3%] vs AFL, 28/224 [12.5%]). The serum concentration profiles and cumulative incidences of overall antidrug antibody positive participants were comparable.Conclusions and RelevanceIn this phase 3 randomized clinical trial, SB15 and AFL showed equivalent efficacy and comparable safety, pharmacokinetics, and immunogenicity in participants with nAMD.Trial RegistrationClinicalTrials.gov Identifier: NCT04450329

Background: SB12 has been developed as a biosimilar of the reference product (RP) eculizumab. Eculizumab is a humanized monoclonal antibody (IgG2/4 kappa immunoglobulin) that binds to the human C5 complement protein with high affinity. Binding to this protein blocks its cleavage into C5a and C5b, thereby inhibiting terminal complement-mediated intravascular haemolysis. It is currently indicated for the treatment of patients with paroxysmal nocturnal haemoglobinuria, atypical haemolytic uremic syndrome (aHUS), refractory generalized Myasthenia Gravis (gMG) and Neuromyelitis Optica Spectrum Disorder (NMOSD). Objectives: To demonstrate pharmacokinetic (PK) equivalence and evaluate pharmacodynamic (PD), safety, tolerability, and immunogenicity profiles between SB12 and the RP eculizumab. Methods: This was a double-blind, three-arm, parallel group, and single-dose study in healthy subjects, between 18-55 years of age, randomized in a ratio of 1:1:1 to receive a single 300 mg dose of either SB12, European Union (EU) sourced eculizumab, or United States of America (US) sourced eculizumab via intravenous (IV) infusion for 35 minutes. Blood samples for PK and PD analysis were collected over 64 days. The primary objective of this study was to demonstrate PK similarity between the investigational products (IPs), as assessed by area under the concentration-time curve from time zero to infinity (AUC inf). Secondary PK endpoints included area under the concentration-time curve from time zero to the last quantifiable concentration (AUC last) and maximum observed concentration (C max). Equivalence for the primary endpoint (AUC inf) was determined if 90% confidence intervals (CIs) for the ratio of geometric least squared means (LSMeans) of SB12 to EU sourced eculizumab, SB12 to US sourced eculizumab, and EU sourced eculizumab to US sourced eculizumab was within the equivalence margin of 80.00% to 125.00%, respectively. Other objectives for the study were to evaluate safety, tolerability, immunogenicity, and PD profiles for the IPs. Results: A total of 240 subjects (80 in each treatment group) were enrolled. Back transformation provided the geometric LSMean ratio for the comparison of SB12/EU sourced eculizumab, SB12/US sourced eculizumab and EU sourced eculizumab/US sourced eculizumab for AUC inf were 99.1 % (95.41,102.85), 95.1 % (91.40, 99.04), and 96.0 % (92.16, 100.10), respectively. The corresponding 90% CI was within the pre-defined equivalence margin of 80.00-125.00%, indicating that the each of two treatments are bioequivalent. The profiles of mean terminal complement activity and mean change from baseline of complement activity were superimposable following administration of SB12, EU sourced eculizumab, and US sourced eculizumab. There was a rapid decrease in the complement activity at the end of infusion and then a slow restoration. There was no non-responder in the aspect of the measured complement activity after treatment. There were no deaths or discontinuation of IP due to treatment-emergent adverse events (TEAEs) during the study. Two serious adverse events (SAEs) (renal colic in the SB12 treatment group and back pain in the US eculizumab treatment group) were reported, in 2 subjects. Both events were considered not related to the IP. The proportion of subjects who experienced TEAEs were similar between the SB12, EU sourced eculizumab, and US sourced eculizumab treatment groups (70.0%, 65.0%, and 71.3% of subjects, respectively). The overall incidence of subjects with post-dose anti-drug antibodies (ADA) to eculizumab was 2 (2.5%), 1 (1.3%), and 0 (0.0%) subjects in the SB12, EU sourced eculizumab, and US sourced eculizumab treatment groups, respectively. There was no significant difference between treatment groups. None of the subjects with post-dose ADA to eculizumab had a positive result for neutralizing antibodies. Conclusion: The Phase I study demonstrated PK bioequivalence and showed comparable PD, safety, immunogenicity between SB12 and the RP eculizumab. Disclosures Lee: Samsung Bioepis, Co., Ltd.: Current Employment. Jang: Samsung Bioepis, Co., Ltd.: Current Employment. Kim: Samsung Bioepis, Co., Ltd.: Current Employment. Jeong: Samsung Bioepis, Co., Ltd.: Current Employment. Lee: Samsung Bioepis, Co., Ltd.: Current Employment. Jung: Samsung Bioepis, Co., Ltd.: Current Employment. Demichelis: Novartis: Consultancy, Research Funding, Speakers Bureau; Bristol/Celgene: Consultancy, Speakers Bureau; AMGEN: Consultancy, Speakers Bureau; ASH: Research Funding; Jazz: Consultancy; Gilead: Consultancy; Astellas: Consultancy; Abbvie: Consultancy, Speakers Bureau.

Background: SB3 (trastuzumab-dttb) is a biosimilar approved globally based on its similarity with reference trastuzumab (TRZ) demonstrated by thorough comparability exercises in analytical, biological, and clinical studies. In a randomized, double-blind, multicenter Phase 3 study of 875 patients with HER2-positive early or locally advanced breast cancer in the neoadjuvant setting, equivalent efficacy, similar safety, pharmacokinetics, and immunogenicity between SB3 and TRZ were shown. However, when quality attributes of TRZ were examined, downward drifts in antibody-dependent cell-mediated cytotoxicity activities (ADCC) were observed in the TRZ lots with expiry dates ranging from Aug 2018 to Dec 2019. Some of these lots of the reference product were found to be used in the Phase 3 study. After completing the Phase 3 study, patients from select countries were included in a follow-up observational study to monitor cardiac safety and survival. Here, we report the final survival results, including post-hoc subgroup analysis based on ADCC status, at a median follow-up of 68 months. Methods: During the follow-up observational study, the protocol was amended to include additional patients who originally were enrolled in the Phase 3 study but had not been followed in the observational study, in order to collect a larger sample of survival data. For these additional patients, medical records from the last assessment in the Phase 3 study through the date of enrollment in the follow-up study were collected retrospectively. As post-hoc analysis, patients in the TRZ arm were stratified into two subgroups: patients who received during neoadjuvant treatment at least one vial of TRZ with downward drift in ADCC as “Drifted TRZ”, and the others as “Non-drifted TRZ”. Event-free survival (EFS) and overall survival (OS) were assessed. Results: Of 875 patients randomized in the Phase 3 study, 538 patients (SB3, N=267; TRZ, N=271) were enrolled in the follow-up observational study: 367 patients were initially enrolled in the follow-up study, and 171 patients were additionally enrolled following the protocol amendment. The median follow-up duration was 68 months from randomization in the Phase 3 study. 54 events (20.2%) in the SB3 arm, and 67 events (24.7%) in the TRZ arm were reported (HR 0.84 [0.58, 1.20], p=0.335). 22 deaths (8.2%) and 38 deaths (14%) were reported in SB3 and TRZ arms, respectively (HR 0.61 [0.36, 1.05], p=0.073). In post-hoc analysis, of 271 patients in TRZ arm, 107 patients were grouped as “Non-drifted TRZ”, and 164 patients as “Drifted TRZ”. 19 events (17.8%) in the Non-drifted TRZ group and 48 (29.3%) events in the Drifted TRZ group occurred (HR 2.57 [1.28, 5.14], p=0.008). 9 deaths (8.4%) in the Non-drifted TRZ group and 29 deaths (17.7%) in the Drifted TRZ group were reported (HR 3.87 [1.37, 10.93], p=0.011). No difference was observed between SB3 arm and Non-drifted TRZ group in terms of EFS (HR 1.28 [0.73, 2.22], p=0.391) and OS (HR 0.99 [0.42, 2.31], p=0.975). Conclusions: Comparable long-term efficacy results in EFS and OS were shown at 68 months of follow-up, further supporting biosimilarity of SB3 to the reference product. Currently, these follow-up results represent the longest monitoring data of patients treated with a trastuzumab biosimilar for HER2-positive early or locally advanced breast cancer. Citation Format: Xavier Pivot, Mark D Pegram, Javier Cortes, Diana Lüftner, Gary H Lyman, Giuseppe Curigliano, Igor M Bondarenko, Mikhail Dvorkin, Jin Hee Ahn, Seock-Ah Im, Maria Litwiniuk, Yaroslav V Shparyk, Gwo Fuang Ho, Nikolay V Kislov, Marek Wojtukiewicz, Tomasz Sarosiek, Yee Soo Chae, Jin Seok Ahn, Hyerin Jang, Sujung Kim, Jiwon Lee, Soo Young Lee, Ye Chan Yoon. Final survival analysis of a phase 3 study comparing SB3 (trastuzumab biosimilar) and reference trastuzumab in HER2-positive early or locally advanced breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P2-13-04.