NT-23PHASE 1/2A STUDY OF GLUTATHIONE PEGYLATED LIPOSOMAL DOXORUBICIN (2B3-101) IN BREAST CANCER PATIENTS WITH BRAIN METASTASES (BCBM) OR RECURRENT HIGH GRADE GLIOMAS (HGG)

BACKGROUND: Without active delivery across the blood-brain barrier, the efficacy of doxorubicin is limited in the treatment of brain tumors. 2B3-101 was developed as a brain-targeted doxorubicin product. In preclinical studies, 2B3-101 showed a 5-fold increased delivery of doxorubicin to the brain and improved survival of mice with HGG, compared to Caelyx®. METHODS: This open-label study assessed the safety, tolerability, MTD, PK and anti-tumor activity of 2B3-101. For this analysis, 30 HGG and 25 BCBM patients were included who received a 2B3-101 starting dose of 40-70 mg/m2 q21d (n = 35) or 60 mg/m2 q28d (n = 20 all HGG). Treatment continued until disease progression or unacceptable toxicity. Anti-tumor activity was assessed by RANO in HGG or RECIST 1.1 in BCBM patients. RESULTS: As of 30-May-2014, 172 cycles (range 1-10) of 2B3-101 were administrated, 4 HGG and 2 BCBM patients are still on treatment. 2B3-101 was tolerated up to a dose-intensity of 15 mg/m2/wk. Cycle 1 MTD was not reached. Phase 2a doses were selected based upon tolerability after repeated dosing. Most frequent reported treatment emergent AEs ≥ grade 2 were: neutropenia (41%), palmar-plantar erythrodysesthesia (PPE) (39%), fatigue (36%), stomatitis (21%), and infusion-reaction (20%). Notable grade 3–4 AEs were neutropenia (26%) and PPE (14%). All were transient and manageable with standard medication or dose delays. Dose reductions were required in 25% of the patients. 2B3-101 showed no neuro-or cardiotoxicity. In 25 evaluable HGG patients, 52% had SD as best response and 3-months PFS rate of 40%. 3 patients had intracranial response of ≥ 20%. In 23 evaluable BCBM patients, 9% had PR and 48% SD as overall best response with 3-months PFS rate of 48%. 4 patients had intracranial response of ≥ 20%. CONCLUSIONS: 2B3-101 is safe, well tolerated and shows promise as a potential treatment option for progressive HGG and BCBM patients.