New data on breast cancer candidate sends Ambrx Biopharma skyward

Clinical-stage biopharmaceutical company Ambrx Biopharma’s (NYSE: AMAM) shares skyrocketed a whopping 1,000% by close of trading on Friday as it announced encouraging results in the Phase II trial of breast cancer drug ARX788.

Ambrx announced preliminary safety and efficacy data from its Phase II ACE‑Breast-03 study during a Spotlight Poster Presentation at the 2022 San Antonio Breast Cancer Symposium (SABCS). The data presented by the investigator demonstrated 51.7% overall response rate (ORR) by RECIST v1.1 and 100% disease control rate (DCR) after treatment with ARX788 in HER2 positive mBC patients who are resistant or refractory to T-DM1.

ACE-Breast-03 is a Phase II, multicenter study of ARX788, an anti-HER2 ADC being evaluated for patients whose metastatic disease is resistant or refractory to T-DXd, T-DM1, or tucatinib-containing regimens. The study was conducted in the USA, Korea, and Australia. As of the data cut-off, seven patients enrolled in the study were previously treated with T-DM1 and received a median of five lines of prior anticancer therapies. Four of seven patients were previously treated with HER2 tyrosine kinase inhibitors (TKIs).