Phase II trial of humanized anti-Lewis Y monoclonal antibody for advanced hormone receptor-positive breast cancer that progressed following endocrine therapy

Authors

DOI:

https://doi.org/10.6061/clinics/2021/e3146

Keywords:

Breast Cancer, Metastatic, Anti-Lewis Y, Monoclonal Antibody, Targeted Therapy

Abstract

OBJECTIVES: The Lewis-Y antigen is expressed in 44%-90% of breast cancers (BCs). The expression of the antigen in carcinoma tissue differs from that in normal tissues. This study aimed to evaluate the clinical benefit of the humanized anti-Lewis Y monoclonal antibody, hu3S193, in advanced hormone receptor-positive and Lewis Y-positive BC after administration of endocrine therapy (ET).

METHODS: A single-arm phase II study was conducted in seven centers. Patients with advanced hormone receptor-positive BC who failed first-line ET were included. The inclusion criterion was the observation of tumoral expression of the Lewis Y antigen during immunohistochemistry. The treatment comprised hu3S193 antibody administration at weekly intravenous doses of 20 mg/m2 for 8-week cycles. The primary endpoint was the clinical benefit rate. ClinicalTrials.gov NCT01370239.

RESULTS: The study stopped accrual following an unplanned interim analysis as the hu3S193 antibody lacked sufficient activity to justify continuation of the study. Twenty-two patients were enrolled, of whom 21 were included in the efficacy analysis. The clinical benefit rate was 19%, with four patients presenting with stable disease after 24 weeks. One patient with prolonged stable disease received medication for over 2 years. No partial or complete responses were observed. The median time to progression and overall survival was 5.4 and 37.5 months, respectively.

CONCLUSIONS: The humanized anti-Lewis Y monoclonal antibody, hu3S193, exhibited insufficient activity in this cohort. However, the possibility of activity in a more strictly selected subgroup of patients with higher levels of Lewis Y tumoral expression cannot be overlooked.

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Published

2021-10-11

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Section

Original Articles

How to Cite

Testa, L., Mano, M., Arai, R. J., Bonadio, R. C., Serrano, S. V., Zorzetto, M. M. C., Crocamo, S., Smaletz, O., Freitas-Junior, R., & Hoff, P. M. (2021). Phase II trial of humanized anti-Lewis Y monoclonal antibody for advanced hormone receptor-positive breast cancer that progressed following endocrine therapy. Clinics, 76, e3146. https://doi.org/10.6061/clinics/2021/e3146