Inotuzumab Leads to Remission in 58% of Children with Relapsed/Refractory B-ALL

Published March 2022 | Journal of Clinical Oncology

A recently published phase II clinical trial demonstrated that inotuzumab ozogamicin (InO) is safe and effective as a single-agent therapy in treating children and adolescents with relapsed or refractory B-cell acute lymphoblastic leukemia (B-ALL).

The study’s principal investigator, Maureen O’Brien, MD, MS, director of the Leukemia/Lymphoma Program at Cincinnati Children’s, also is co-principal investigator for a second study that will evaluate InO’s safety and effectiveness when combined with chemotherapy in treating newly diagnosed high-risk B-ALL. Both studies are sponsored by Children’s Oncology Group.

InO is a CD22-targeting antibody-drug conjugate approved by the U.S. Food and Drug Administration to treat adults with relapsed or refractory B-ALL. CD22 is a surface protein expressed on leukemic blasts in about 95% of B-ALL cases.

The phase II study of single-agent InO in relapse included 48 heavily pretreated patients ages 1 to 21 years with CD22-positive relapsed/refractory B-ALL.

“The patients who participated in this trial had few avail-able treatment options; many had received multiple intensive chemotherapy regimens and/or immunotherapies and had subsequently relapsed or did not respond,” says O’Brien. “InO as a single agent led to remission in 28 patients (58.3%), many of whom went on to receive subsequent curative therapy—either hematopoietic stem-cell transplantation (HSCT) or CAR-T (chimeric antigen receptor T cell) therapy.”

The phase II trial is enrolling a second cohort of patients with relapse who are receiving InO in combination with chemotherapy. The phase III study for newly diagnosed patients will enroll about 3,700 patients ages 1 to 25 years at 213 cancer centers in the US, Canada, Australia and New Zealand over the next four years.

Oncology research discovery findings.

Individual patient response, subsequent therapy, and outcomes for 48 patients. Patients with Down syndrome are denoted as DS.Dark bars indicate InO given on study. Initial response to cycle 1 is indicated by CR, CRi,PR, SD, or PD. For patients who received cycle 2, response is indicated as CCR or CCRi if previously achieved CR or CRi with cycle 1. Duration of initial response is indicated by color (CR or CRi5blue; PR or SD5red, PD5gray). HSCT is indicated by star, and CAR T-cell therapy is indicated by triangle. C, censored; CAR, chimeric antigen receptor; CCR, continuous complete response; CCRi, continuous complete response with incomplete count recovery; CR, complete response with or without count recovery; CRi, complete response with incomplete count recovery; D, death; DS, Down syndrome; HSCT, hematopoietic stem-cell transplantation; InO, inotuzumab ozogamicin; PD, progressive disease; PR, partial response; R, relapse; SD, stable disease; SMN, second malignant neoplasm.

Meet the Researcher

A photo of Maureen O'Brien.

Citation

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.