RRC ID 89788
Author Yamamoto R, Asano H, Hatanaka KC, Shinomiya Y, Yamazaki H, Matsumiya H, Nagamine M, Sasajima Y, Hatanaka Y, Watari H.
Title Feasibility study of photoimmunotherapy combination with ASP-1929 for vulvar, vaginal, and cervical cancer.
Journal J Gynecol Oncol
Abstract OBJECTIVE:The aim of this study was to evaluate the feasibility of photoimmunotherapy (PIT) using ASP-1929, an anti-epidermal growth factor receptor (EGFR) antibody-dye conjugate, for vulvar, vaginal, and cervical cancers by validating EGFR expression and establishing immunohistochemistry (IHC)-based eligibility criteria for a phase II trial, HICARi study.
METHODS:Cetuximab-binding activity was analyzed in gynecologic cancer cell lines (CaSki, HeLa, and Ishikawa) using flow cytometry and compared with positive controls (A431 and BxPC-3) and a low-EGFR control (MCF-7). IHC was performed on cell blocks and clinical specimens of vulvar, vaginal, and cervical cancers (validation cohort, n=27; screening cohort, n=40).
RESULTS:CaSki demonstrated comparable or higher EGFR binding than BxPC-3, whereas HeLa and Ishikawa showed weaker binding. IHC staining intensity correlated with flow cytometry findings. Squamous cell carcinomas consistently exhibited moderate-to-strong EGFR expression, whereas non-squamous carcinomas displayed variable expression. EGFR positivity was defined as >30% of tumor cells with at least moderate membranous staining (2+ or 3+). In the validation cohort, EGFR positivity was observed in 71.4% of the vulvar, 80.0% of the vaginal, and 87.5% of the cervical cancers. The screening cohort showed similar rates: 88.9% of vulvar, 100% of vaginal, and 75.0% of cervical cancers.
CONCLUSION:We demonstrated correlation between cetuximab-binding and IHC staining intensity, establishing IHC criteria (≥2+) for patient selection. EGFR positivity (71.4%-87.5%) indicates substantial eligibility for ASP-1929 PIT. Therapeutic efficacy will be evaluated in the HICARi study.
Published 2026-5-21
DOI 10.3802/jgo.2026.37.e125
PII 37.e125
PMID 42210770
Resource
Human and Animal Cells Ca Ski(RCB1947) HeLa