ANG1005, a Brain-Penetrating Peptide–Drug Conjugate, Shows Activity in Patients with Breast Cancer with Leptomeningeal Carcinomatosis and Recurrent Brain Metastases

Purpose: ANG1005, a novel taxane derivative, consists of three paclitaxel molecules covalently linked to Angiopep-2, designed to cross the blood–brain and blood–cerebrospinal barriers and to penetrate malignant cells via LRP1 transport system. Preclinical and clinical evidence of efficacy with ANG1005 has been previously shown. Patients and Methods: A multicenter, open-label phase II study in adult patients with measurable recurrent brain metastases from breast cancer (BCBM), with or without leptomeningeal carcinomatosis was conducted (n = 72 BCBM; n = 28 leptomeningeal carcinomatosis subset). ANG1005 was administered intravenously at 600 mg/m² every 3 weeks. Tumor assessment was based on central nervous system (CNS) RECIST 1.1 for intracranial, and RECIST 1.1 for extracranial response. The primary endpoint was determination of intracranial objective response rate (iORR). Results: Median age was 47.5 years. Safety profile was similar to that of paclitaxel with myelosuppression as the predominating toxicity. Average number of prior CNS-directed therapies was 2.8 and 94% of the patients had prior taxane treatment. Patient benefit (stable disease or better) was seen in 77% (intracranial) and 86% (extracranial) of the evaluable patients, with iORR of 15% (investigator) or 8% (independent radiology facility [IRF] review). In the leptomeningeal carcinomatosis subset, 79% of the patients had intracranial disease control and estimated median overall survival of 8.0 months (95% CI, 5.4–9.4). Conclusions: Even though the study preset rule for iORR per IRF was not met in this heavily pretreated population, a notable CNS and systemic treatment effect was seen in all patients including symptom improvement and prolonged overall survival compared to historical control for the subset of patients with leptomeningeal carcinomatosis (n = 28).