This study evaluated the efficacy and safety of CD38-targeting antibody isatuximab combined with standard chemotherapy in pediatric relapsed/refractory acute leukemia, providing preliminary data for application of anti-CD38 therapy in pediatric hematological malignancies.
Literature Overview
The article, titled 'Isatuximab in combination with chemotherapy for pediatric patients with relapsed/refractory acute lymphoblastic leukemia or acute myeloid leukemia: The ISAKIDS study', published in the journal HemaSphere, reviewed and summarized the results of the ISAKIDS clinical trial, which assessed the efficacy and safety of isatuximab combined with chemotherapy in pediatric patients with relapsed/refractory acute leukemia. The study results showed that although the overall complete remission rate (CR/CRi) was 54%, the study failed to meet the prespecified criteria for advancing to stage II. Additionally, some patients experienced severe adverse events, particularly those with high white blood cell counts who developed fatal cytokine release syndrome (CRS).
Background Knowledge
Acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) are the most common hematological malignancies in children. Although long-term survival rates have significantly improved with current frontline therapies, treatment remains challenging for relapsed or refractory cases, which are associated with poor patient outcomes and limited efficacy from conventional chemotherapy and hematopoietic stem cell transplantation (HSCT). CD38, a transmembrane receptor widely expressed on B-cell and T-cell malignancies, represents a promising target for antibody-based therapies. Isatuximab (Isa), a monoclonal antibody targeting CD38, is approved for adult multiple myeloma and exerts its antitumor effects via antibody-dependent cellular cytotoxicity (ADCC), complement-dependent cytotoxicity (CDC), and induction of NK cell activation. However, its efficacy in pediatric acute leukemias remains unclear. This study aimed to assess the efficacy and safety of isatuximab combined with chemotherapy in pediatric ALL and AML based on the high expression of CD38 in these diseases, seeking to provide novel therapeutic strategies for relapsed/refractory patients.
Research Methods and Experiments
The ISAKIDS study is a multicenter, single-arm, phase II clinical trial involving pediatric patients aged 28 days to 18 years with relapsed/refractory T-ALL, B-ALL, or AML. All patients received isatuximab 20 mg/kg on Day 1 as induction therapy, followed by weekly dosing for 5 weeks (for ALL) or 3 weeks (for AML). Standard chemotherapy was initiated on Day 8, although it could be started earlier based on the patient's clinical condition. Patients achieving CR/CRi could proceed to consolidation therapy. The primary endpoint was the CR/CRi rate, while secondary endpoints included the minimal residual disease (MRD) negativity conversion rate and safety evaluation.
Key Conclusions and Perspectives
Research Significance and Prospects
This study is the first to assess the efficacy and safety of isatuximab in combination with chemotherapy in pediatric patients with relapsed/refractory ALL and AML, providing initial data for the use of anti-CD38 therapy in this population. While the prespecified response thresholds were not met, a subset of patients did achieve deep remission and MRD conversion, suggesting potential therapeutic benefit in certain subgroups. Future studies may focus on optimizing the timing of treatment or combining with other targeted or immunotherapeutic approaches to enhance efficacy. Furthermore, the occurrence of severe CRS in patients with high baseline WBC highlights the need for careful patient selection and close monitoring for toxicities.
Conclusion
The ISAKIDS study demonstrated that isatuximab combined with chemotherapy has some antitumor activity in pediatric patients with relapsed/refractory acute leukemias, but the overall response rate did not meet the prespecified criteria for proceeding to stage II. CR/CRi rates were 52% in B-ALL, 45% in T-ALL, and 61% in AML. Among patients who achieved CR/CRi, 56% became MRD negative. Although toxicity was generally manageable, one AML patient with a high baseline WBC experienced fatal CRS, leading to protocol modifications. The study did not confirm a direct correlation between CD38 expression levels and treatment efficacy, suggesting the need for more complex biomarker analyses. Future research may explore earlier lines of isatuximab treatment or combinations with other targeted agents to optimize therapeutic outcomes.
