There a number of case reports of Mekenist coming after dabrafenib, with Avastin and by itself or i combination with dabrafenib, but no clinical trials.
Migliorini D, Aguiar D, Vargas MI, Lobrinus A, Dietrich PY. BRAF/MEK double blockade in refractory anaplastic pleomorphic xanthoastrocytoma. Neurology. 2017;88(13):1291-1293.
CNS ONCOLOGYVOL. 6, NO. 1 CASE REPORT
Dabrafenib in BRAFV600-mutated anaplastic pleomorphic xanthoastrocytoma
Nicholas F Brown, Thomas Carter & Paul Mulholland
Hussain F et al, Response to BRAF/MEK Inhibition After Progression With BRAF Inhibition in a Patient With Anaplastic Pleomorphic Xanthoastrocytoma.
Neurologist. 2018 Sep;23(5):163-166.