INCHEON, Korea, Sept. 12, 2021 (GLOBE NEWSWIRE) -- Samsung Bioepis Co., Ltd. today announced findings of a five-year follow-up study comparing ONTRUZANT® (trastuzumab) and reference medicine trastuzumab in early or locally advanced HER2 positive breast cancer. The results, which show comparable cardiac safety profiles and long-term efficacy, will be presented at the European Society for Medical Oncology (ESMO) Virtual Congress 2021.
"The five-year follow-up results presented at this year's ESMO is the longest monitoring data of patients treated with a trastuzumab biosimilar for HER2-positive early or locally advanced breast cancer," said Donghoon Shin, Vice President and Medical and Lifecycle Safety Team Leader at Samsung Bioepis. "This valuable data signifies our continuous dedication in producing high-quality treatments with proven efficacy and safety. We remain committed to patients we serve through our rigorous research and development to ensure quality treatment. We look forward to sharing our data with the oncology community on the usage of biosimilars based on this long-term follow-up data."
The enrolled patients received eight cycles of the biosimilar trastuzumab or the reference medicine concurrently with chemotherapy in neoadjuvant setting. Following the surgery, they received 10 cycles of the biosimilar trastuzumab or reference medicine completing 1 year of treatment. After the Phase 3 study, 367 patients participated in the follow-up study (186 in the biosimilar trastuzumab group and 181 in the reference medicine group) with the median follow-up duration being 68 months from randomization.
During treatment-free follow-up period, the asymptomatic significant left ventricular ejection fraction (LVEF) decrease rarely occurred for both groups (biosimilar trastuzumab, n=1; reference medicine, n=2) with all three patients recovering with LVEF ≥ 50%. There were no reported cases of symptomatic congestive heart failure or cardiac death reported in either group. Meanwhile, number of events, defined as recurrence, progression, or death, were reported in 32 patients (17.2%) in the biosimilar trastuzumab group and 38 patients (21%) in the reference medicine group (Hazard Ratio (SB3/TRZ) 0.78; 95% CI 0.48-1.25; p=0.30). Five-year event-free survival rates were 82.8% in the biosimilar trastuzumab group and 79.7% in the reference medicine group. Five-year overall survival rates were 93.1% in the biosimilar trastuzumab group and 86.7% in the reference medicine group (Hazard Ratio (SB3/TRZ) 0.62; 95% CI 0.32-1.22; p=0.17). ii
The results of the five-year follow up of ONTRUZANT® Phase 3 study will be presented as an e-poster during ESMO on Thursday, September 16, 2021.
Five-year follow-up of ONTRUZANT® (trastuzumab) Phase 3 study
The five-year follow-up of the Phase 3 study comparing ONTRUZANT® (trastuzumab biosimilar) and reference trastuzumab (TRZ) in patients with HER2 positive early or locally advanced breast cancer for comparable cardiac safety profiles, and efficacy at 4 years after randomization in the Phase 3 study. Of 875 patients randomized in the Phase 3 study, 367 patients (ONTRUZANT®, N=186; TRZ, N=181) were enrolled in the follow-up study and were randomly assigned to receive 8 cycles of either ONTRUZANT®, or TRZ with concurrent neoadjuvant chemotherapy (4 cycles of docetaxel followed by 4 cycles of 5-fluorouracil/epirubicin/cyclophosphamide). Patients then underwent surgery followed by 10 cycles of ONTRUZANT® or TRZ according to the previous treatment allocation to complete 1 year of treatment. After completing the adjuvant treatment, patients from selected countries were asked for consent to enroll in a follow-up observation study. The objective of the study was to monitor cardiac toxicity, event-free survival (EFS), and overall survival (OS).
About Samsung Bioepis Co., Ltd.
Established in 2012, Samsung Bioepis is a biopharmaceutical company committed to realizing healthcare that is accessible to everyone. Through innovations in product development and a firm commitment to quality, Samsung Bioepis aims to become the world's leading biopharmaceutical company. Samsung Bioepis continues to advance a broad pipeline of biosimilar candidates that cover a spectrum of therapeutic areas, including immunology, oncology, ophthalmology, hematology and endocrinology. For more information, please visit: www.samsungbioepis.com  and follow us on social media - Twitter , LinkedIn .
Yoon Kim: firstname.lastname@example.org 
i HERCEPTIN® is a registered trademark of Genentech Inc.
ii X. Pivot, O. Burian, F. Bazan, M. Wojtukiewicz, H. Jang, S. Kim, J. Lee, Y. Yoon. Five-year follow-up of the Phase 3 study comparing SB3 (trastuzumab biosimilar) and reference trastuzumab in patients with HER2 positive early or locally advanced breast cancer. ESMO 2021. Abstract 1520P.