Disitamab vedotin extended median progression-free survival to 9.9 months compared to 4.9 months with lapatinib plus capecitabine in patients with HER2-positive advanced breast cancer and liver metastases, according to trial results published in Nature Communications. The prospective, randomized RC48-C006 trial met its pre-specified primary endpoint.
The open-label phase 3 study evaluated 104 patients who had previously undergone treatment with trastuzumab and taxanes. Investigators randomized 53 participants to receive disitamab vedotin and 51 participants to receive lapatinib plus capecitabine.
A blinded Independent Review Committee calculated a stratified hazard ratio of 0.56, with a 95.48% confidence interval of 0.35 to 0.91 and a two-sided P value of 0.01. Assessments performed by trial investigators matched the committee's findings, and prespecified subgroup analyses consistently showed superior progression-free survival for disitamab vedotin.
Safety outcomes between the two treatment regimens remained close. Clinicians reported grade 3 or higher treatment-related adverse events in 37.7% of patients treated with disitamab vedotin, compared to 36.0% of patients receiving lapatinib plus capecitabine.
RemeGen sponsored the study and contributed to trial design, oversight, data collection, analysis, and manuscript review. Additional financial support came from China's Noncommunicable Chronic Diseases-National Science and Technology Major Project and the Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences.
