Efficacy and Safety of Intrathecal Administration of Thiotepa in Combination With Trastuzumab in Breast Cancer With Leptomeningeal Metastasis

This was a II, single-arm, prospective, multicenter study designed to estimate the efficacy and safety of intrathecal administration of thiotepa in combination with Trastuzumab via the Ommaya Reservoir in HER2-positive breast cancer with leptomeningeal metastasis. The primary end point was iORR \[complete response (CR) + partial response (PR)\] according to RANO-LM. Scoring based on radiographic assessment in leptomeningeal metastases . A composite score (total score) is calculated and compared with the baseline total score. A 25% worsening in the current score relative to baseline defines radiographic progressive disease. A 50% improvement in the current score defines a radiographic partial response. Resolution of all baseline radiographic abnormalities defines a complete response. All other situations define stable disease. The secondary end points were changes in iPFS,PFS, OS, and exploratory analysis of the relationship between molecular markers and therapeutic efficacy. This study is planned to include 26 patients with leptomeningeal metastasis from breast cancer who meet the entry criteria.