Bakker, Annette

Abstract INTRODUCTION Brigatinib is an oral ALK inhibitor that inhibits multiple tyrosine kinases. We previously published outcomes of patients with NF2-related schwannomatosis treated with brigatinib for a median of 10.4 months. We report updated results of these patients with extended follow-up. METHODS This multicenter, phase II, open-label study included participants ≥12 years with NF2-SWN and progressive target tumors (baskets: VS, NVS, meningioma, or ependymoma). Patients were treated with brigatinib 180 mg daily. Patients discontinued treatment upon progression of target tumors but could continue treatment with isolated progression of non-target tumors if deemed clinically acceptable by the treating team and patient. One target and up to 5 non-target tumors were followed in each participant. Tumor response was evaluated by MRI every 3 months in year 1 and every 6 months thereafter with radiographic response (RR) defined as ≥20% decrease in volume compared to baseline. RESULTS Forty participants were treated for a median of 23 months (range, 3-40 months). Updated imaging data is available on 162 tumors (45 VS, 59 non-VS, 53 meningiomas, and 5 ependymomas). RR rate for all tumors was 28% and was 31% for non-VS, 28% for meningioma, 22% for VS, and 60% for ependymomas. The 12-month freedom from tumor progression was 77.1% for all tumors, 81.5% for non-VS, 78.1% for meningioma, 69.2% for VS, and 100.0% for ependymoma. The 24-month freedom from tumor progression was 73% for all tumors, 81.3% for non-VS, 72.4% for meningioma, 62.4% for VS, and 100.0% for ependymoma. There were no grade 4/5 treatment-related adverse events (AEs). The most common AEs were diarrhea (65%), nausea (40%), muscle cramps (40%), hypertension (35%), increased LDH (35%), increased AST (33%), and increased ALT (25%). CONCLUSION Brigatinib treatment was associated with high rates of tumor stability at 24 months across multiple tumor types in patients with NF2-related schwannomatosis.