Phase II Trial of Inotuzumab Ozogamicin in Children and Adolescents With Relapsed or Refractory B-Cell Acute Lymphoblastic Leukemia: Children’s Oncology Group Protocol AALL1621

O’Brien MM, Ji L, Shah NN, Rheingold SR, Bhojwani D, Yuan CM, Xu X, Yi JS, Harris AC, Brown PA, Borowitz MJ, Militano O, Kairalla J, Devidas M, Raetz EA, Gore L, Loh ML. Phase II Trial of Inotuzumab Ozogamicin in Children and Adolescents With Relapsed or Refractory B-Cell Acute Lymphoblastic Leukemia: Children’s Oncology Group Protocol AALL1621. J Clin Oncol. 2022 Mar 20;40(9):956-967. doi: 10.1200/JCO.21.01693. Epub 2022 Jan 10. PubMed PMID: 35007127; PubMed Central PMCID: PMC8937013.

Children’s Oncology Group trial AALL1621 was conducted to prospectively determine the safety and efficacy of inotuzumab ozogamicin (InO) in pediatric and adolescent patients with relapsed or refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL). This single-arm phase II trial enrolled patients age 1-21 years with R/R CD22-positive B-ALL. In cycle 1, InO dosing was 0.8 mg/m2 intravenously on day 1 and 0.5 mg/m2 on days 8 and 15 of a 28-day cycle with response evaluation at day 28. Using a two-stage design, the trial was continuously monitored for dose-limiting toxicities and sinusoidal obstruction syndrome (SOS). CD22 expression was retrospectively evaluated by central flow cytometry.