Pediatric and adult high-grade gliomas (HGGs) frequently harbor PDGFRA alterations. We hypothesized that cotreatment with everolimus may improve the efficacy of dasatinib in PDGFRα-driven glioma through combinatorial synergism and increased tumor accumulation of dasatinib. We performed dose-response, synergism, P-glycoprotein inhibition, and pharmacokinetic studies in in vitro and in vivo human and mouse models of HGG. Six patients with recurrent PDGFRα-driven glioma were treated with dasatinib and everolimus. We found that dasatinib effectively inhibited the proliferation of mouse and human primary HGG cells with a variety of PDGFRA alterations. Dasatinib exhibited synergy with everolimus in the treatment of HGG cells at low nanomolar concentrations of both agents, with a reduction in mTOR signaling that persisted after dasatinib treatment alone. Prolonged exposure to everolimus significantly improved the CNS retention of dasatinib and extended the survival of PPK tumor–bearing mice (mutant TP53, mutant PDGFRA, H3K27M). Six pediatric patients with glioma tolerated this combination without significant adverse events, and 4 patients with recurrent disease (n = 4) had a median overall survival of 8.5 months. Our results show that the efficacy of dasatinib treatment of PDGFRα-driven HGG was enhanced with everolimus and suggest a promising route for improving targeted therapy for this patient population.
Zachary Miklja, Viveka Nand Yadav, Rodrigo T. Cartaxo, Ruby Siada, Chase C. Thomas, Jessica R. Cummings, Brendan Mullan, Stefanie Stallard, Alyssa Paul, Amy K. Bruzek, Kyle Wierzbicki, Tao Yang, Taylor Garcia, Ian Wolfe, Marcia Leonard, Patricia L. Robertson, Hugh J.L. Garton, Daniel R. Wahl, Hemant Parmar, Jann N. Sarkaria, Cassie Kline, Sabine Mueller, Theodore Nicolaides, Chana Glasser, Sarah E.S. Leary, Sriram Venneti, Chandan Kumar-Sinha, Arul M. Chinnaiyan, Rajen Mody, Manjunath P. Pai, Timothy N. Phoenix, Bernard L. Marini, Carl Koschmann