Safety and Clinical Evaluation of Dual Inhibition with Pertuzumab and Trastuzumab Biosimilar SB3 in HER2-Positive Breast Cancer Patients

Abstract

<b><i>Background:</i></b> The addition of trastuzumab to standard chemotherapy has improved survival in patients with HER2-positive breast cancer in neoadjuvant, adjuvant, and metastatic settings. In higher tumor stages, the addition of pertuzumab is now a standard of care and associated with a favorable toxicity profile. We evaluated the safety and efficacy of the trastuzumab biosimilar SB3 in combination with pertuzumab in HER2-positive breast cancer patients. <b><i>Methods:</i></b> Seventy-eight patients with HER2-positive breast cancer treated at the Division of Oncology at the Medical University of Graz were included. Summary measures are reported as medians (25th to 75th percentile) for continuous variables and as absolute frequencies (%) for count data. <b><i>Results:</i></b> Thirty-five patients received a median of 4 (3–7) cycles of trastuzumab biosimilar SB3 plus pertuzumab. All patients had a normal baseline left ventricular ejection fraction (LVEF; >50%) prior to the initiation of SB3 plus pertuzumab treatment with a median LVEF of 60% (60–65). Twenty-one patients had a median absolute LVEF decline of 1% (–5 to 0). Two patients (5.7%) had a LVEF reduction ≤50%, but none ≥10%. There were no unexpected adverse events. Twenty-two of 35 patients (63%) were treated with trastuzumab biosimilar SB3 and pertuzumab in the neoadjuvant setting and 11 patients (50%) achieved a pathological complete response. The safety and the efficacy in this setting was comparable to the trastuzumab plus pertuzumab combination in neoadjuvantly treated matched samples. <b><i>Conclusion:</i></b> In this series of HER2-positive breast cancer patients, the combination of SB3 plus pertuzumab was consistent with the known safety and efficacy profile of trastuzumab and pertuzumab combination.

Safety and Effectiveness of Trastuzumab Biosimilar SB3 in Korean Patients, a Post-Marketing Surveillance Study

“…Furthermore, concomitant medication was reported as related factor to loss of consciousness, the patient recovered without sequelae, and treatment was continued as planned. Comparable cardiac safety profiles of SB3 (as monotherapy or together with PTZ) and TRZ have been previously demonstrated in clinical trials and real-world settings [24, 31, 33‒36]. In this 4-year PMS study, two events of decreased LVEF but no CHF or cardiac dysfunction were reported, confirming the cardiac safety of SB3.…”

“…† Data shown as n (%). *>5% in any group, p value for difference between SB3 ± CT versus SB3+PTZ ± CT. [24,31,[33][34][35][36]. In this 4-year PMS study, two events of decreased LVEF but no CHF or cardiac dysfunction were reported, confirming the cardiac safety of SB3.…”

A Review of Trastuzumab Biosimilars in Early Breast Cancer and Real World Outcomes of Neoadjuvant MYL-1401O versus Reference Trastuzumab

“…Out of the 78 patients enrolled, 24 patients received neoadjuvant SB3 and 43 patients received neoadjuvant TRZ. tpCR rates were 50% in the SB3 group and 58% in the TRZ group, comparable with landmark neoadjuvant TRZ plus pertuzumab combination studies [ 28 , 29 , 30 ]. Bae et al reported real-world outcomes from a Korean-based population with early-stage or metastatic HER2+ breast cancer.…”