Dual and Inhibition Demonstrates Synergy against Neuroblastoma.

Anaplastic lymphoma kinase () is the most frequently mutated oncogene in the pediatric cancer neuroblastoma. We performed an screen for synergistic drug combinations that target neuroblastomas with mutations in to determine whether drug combinations could enhance antitumor efficacy. We screened combinations of eight molecularly targeted agents against 17 comprehensively characterized human neuroblastoma-derived cell lines. We investigated the combination of ceritinib and ribociclib on proliferation, cell cycle, viability, caspase activation, and the cyclin D/CDK4/CDK6/RB and pALK signaling networks in cell lines with representative ALK status. We performed trials in CB17 SCID mice bearing conventional and patient-derived xenograft models comparing ceritinib alone, ribociclib alone, and the combination, with plasma pharmacokinetics to evaluate for drug-drug interactions. The combination of ribociclib, a dual inhibitor of cyclin-dependent kinase (CDK) 4 and 6, and the ALK inhibitor ceritinib demonstrated higher cytotoxicity ( = 0.008) and synergy scores ( = 0.006) in cell lines with mutations as compared with cell lines lacking mutations or alterations in Compared with either drug alone, combination therapy enhanced growth inhibition, cell-cycle arrest, and caspase-independent cell death. Combination therapy achieved complete regressions in neuroblastoma xenografts with -F1174L and F1245C resistance mutations and prevented the emergence of resistance. Murine ribociclib and ceritinib plasma concentrations were unaltered by combination therapy. This preclinical combination drug screen with validation has provided the rationale for a first-in-children trial of combination ceritinib and ribociclib in a molecularly selected pediatric population. .