Vincristine Sulfate Liposome Injection (VSLI, Marqibo®) in Combination with UK ALL-R3 Induction Chemotherapy for Children, Adolescents and Young Adults with Relapsed Acute Lymphoblastic Leukemia (ALL): A Therapeutic Advances in Childhood Leukemia and Lymphoma (TACL) Consortium Trial

Introduction: Vincristine intensification has the potential to improve outcomes in ALL, but severe neurotoxicity has prohibited escalation beyond standard capped doses. Vincristine sulfate liposome injection, VSLI (Marqibo®) is a liposomal formulation of aqueous vincristine that optimizes pharmacokinetics, prolongs circulating half-life, increases tissue penetration, and may be better tolerated than standard vincristine. VSLI received accelerated FDA approval for adults with relapsed/refractory (r/r) ALL, at a dose of 2.25 mg/m 2/dose without a dose cap. A phase I trial of VSLI in children and young adults with r/r ALL demonstrated safety, tolerability, and evidence for single-agent activity (Shah NN, et al. Pediatric Blood Cancer, 2016). Studies of VSLI with combination chemotherapy in children have not been conducted. With emerging data supporting improved outcomes for patients (pts) with r/r ALL who proceed to immunotherapy with low-burden disease, identifying safe and effective reinduction regimens to reduce disease burden remains a priority.