Salvage therapy with BRAF inhibitors for recurrent pleomorphic xanthoastrocytoma: a retrospective case series

Pleomorphic xanthoastrocytoma (PXA) is a World Health Organization Grade 2 glioma that is uncommon (<1 % all adult gliomas) and seen primarily in children and young adults. PXA has been demonstrated to manifest the V600E BRAF mutation in nearly 70 % of all tumors, a mutation that constitutively activates the BRAF/MEK signaling pathway. Assess response and toxicity of a BRAF inhibitor, vemurafenib, in recurrent PXA manifesting the V600E mutation. Four adults [2 males; 2 female: median age 45 years (range 34–53)] with surgery, radiation and alkylator refractory recurrent PXA demonstrating the BRAF mutation (V600E) were treated with vemurafenib. A cycle of vemurafenib was defined as 4 weeks of continuous therapy. All toxicities seen were grade 2 and included arthralgia, photosensitivity, fatigue and nausea (1 patient each). The median number of cycles of therapy was 5 (range 2–10). Radiographic response was progressive disease in 1, stable disease in 2 and partial response in 1. Median progression free survival was 5 months (range 2–10 months). Median overall survival was 8 months (range 4–14 months). In this small retrospective series of select patients with recurrent PXA manifesting the BRAF V600E activating mutation, vemurafenib appears to have single agent activity with manageable toxicity. Confirmation in a larger series of similar patients is required.