Results Unveiled for the Phase III Study of Disitamab Vedotin in Treating HER2-Positive Advanced Breast Cancer with Liver Metastasis

On the morning of December 12, 2024 (UTC-6), at the Poster Spotlight Session "Novel HER2 Therapeutics" of the 47th San Antonio Breast Cancer Symposium (SABCS), RemeGen Co. Ltd. ("RemeGen") (9995.HK, 688331.SH) presented for the first time the data from a phase III study (RC48-C006, NCT03500380) of Disitamab Vedotin (DV) in treating patients with HER2-positive advanced breast cancer with liver metastasis (BCLM). This is the first prospective randomized phase III study globally on a HER2-targeting ADC that demonstrated significant efficacy in patients with HER2-positive advanced BCLM. Professor Jiayu Wang from the Cancer Hospital, Chinese Academy of Medical Sciences presented and discussed the study. SABCS is one of the largest and most influential annual conferences focusing on advances in breast cancer clinical research, and this RemeGen sponsored study attracted the attention of experts worldwide.

Data shows that about 45% of patients with HER2-positive advanced breast cancer have liver metastasis. This subset has a poor prognosis with a 5-year survival rate of only 8% to 12%, for whom no satisfactory therapies are available now.

This is a randomized, open-label, multicenter phase III study comparing the efficacy and safety of DV versus Lapatinib plus Capecitabine in patients with HER2-positive advanced BCLM. A total of 104 patients were enrolled, of whom 53 received DV and 50 received Lapatinib plus Capecitabine. All patients had previously been treated with Trastuzumab and Taxanes.

As of data cutoff date (December 31, 2023), according to the assessment by the Independent Review Committee (IRC), DV significantly improved progression-free survival (PFS) versus Lapatinib plus Capecitabine (median: 9.9 months vs. 4.9 months; hazard ratio [HR]: 0.56 [95% CI: 0.35-0.90]), which is consistent with the investigator-assessed PFS (HR: 0.62 [95% CI: 0.39-0.98]). The overall survival (OS) data, though immature, indicated a benefit trend in favor of DV. The safety profile was consistent with past DV use experience, with no new safety signals detected.

"This is the first confirmatory phase III study that demonstrated promising efficacy of an HER2-targeting ADC in patients with HER2-positive advanced BCLM," observed Professor Jiayu Wang. DV demonstrated clinically meaningful benefit compared with Lapatinib plus Capecitabine and a manageable safety profile, potentially offering a promising new treatment option for patients with HER2-positive advanced BCLM previously treated with Trastuzumab and Taxanes. The Biologics License Application (BLA) filing for this indication of DV has been accepted by the Center for Drug Evaluation (CDE) of China's National Medical Products Administration in October 2024 and priority review was granted based on the breakthrough therapy designation.

Source: RemeGen Co., Ltd