Case Report: Targeting 2 Antigens as a Promising Strategy in Mixed Phenotype Acute Leukemia: Combination of Blinatumomab With Gemtuzumab Ozogamicin in an Infant With a KMT2A-Rearranged Leukemia

• DOI: 10.3389/fonc.2021.637951
• Publication Date: 2021-02-26T15:03:16Z
• Authors: Benoît Brethon; Elodie Lainey; Aurélie Caye-Eude; Audrey Grain; Odile Fenneteau; Karima Yakouben; Julie Roupret-Serzec; Lou Le Mouel; Hélène Cavé; André Baruchel
• Keywords: Blinatumomab; Gemtuzumab ozogamicin; Lymphoid leukemia; clone (Java method); Minimal Residual Disease

Mixed phenotype acute leukemia (MPAL) accounts for 2-5% of in children. MPAL are at higher risk induction failure. Lineage switch (B to M or vice versa) persistence only the lymphoid myeloid clone is frequently observed biphenotypic/bilineal cases, highlighting their lineage plasticity. The prognosis remains bleak, with an event-free survival (EFS) less than 50% A lymphoid-type therapeutic approach appears be more effective but failures achieve complete remission (CR) remain significant. KMT2A fusions account 75-80% infants under one year age and a major pejorative prognostic factor Interfant-06 protocol 6 years EFS 36%. search other approaches, particular immunotherapies that able eradicate all clones, issue. We describe here feasibility tolerance combination two targeted immunotherapies, blinatumomab Gemtuzumab Ozogamicin, 4-year-old infant primary refractory KTM2A-rearranged MPAL. Our main concern was determine how associate these we decided do it parents’ agreement. good MRD response on clones made possible continue curative intent hematopoietic stem cell transplant 9 months age. Despite relapse M11 post-transplant because recurrence pro-B retaining initial phenotype, child now 36 old, persistent negative CR2 12 after salvage chemotherapy autologous CAR T cells infusion, no known sequelae date. This case study can thus lead idea sequential targeting distinct leukemic subclones (or even single biphenotypic clone), as potential tested prospectively children possibly KMT2A-rearranged ALL.