title: A Phase I Study of Reduced-Intensity Conditioning and Allogeneic Stem Cell Transplantation Followed by Dose Escalation of Targeted Consolidation Immunotherapy with Gemtuzumab Ozogamicin in Children and Adolescents with CD33+ Acute Myeloid Leukemia.
abstract: Myeloablative conditioning and allogeneic hematopoietic stem cell transplant (alloHSCT) in children with acute myeloid leukemia (AML) in first complete remission (CR1) may be associated with significant acute toxicity and late effects. Reduced-intensity conditioning (RIC) and alloHSCT in children is safe, feasible, and may be associated with less adverse effects. Gemtuzumab ozogamicin (GO) induces a response in 30% of patients with CD33+ relapsed/refractory AML. The dose of GO is significantly lower when combined with chemotherapy. We examined the feasibility and toxicity of RIC alloHSCT followed by GO targeted immunotherapy in children with CD33+ AML in CR1/CR2. Conditioning consisted of fludarabine 30 mg/m2 × 6 days, busulfan 3.2 to 4 mg/kg × 2 days ± rabbit antithymocyte globulin 2 mg/kg × 4 days followed by alloHSCT from matched related/unrelated donors. GO was administered ≥60 days after alloHSCT in 2 doses (8 weeks apart), following a dose-escalation design (4.5, 6, 7.5, and 9 mg/m2). Fourteen patients with average risk AML received RIC alloHSCT and post-GO consolidation: median age 13.5 years at transplant (range, 1 to 21), male-to-female 8:6, and disease status at alloHSCT 11 CR1 and 3 CR2. Eleven patients received alloHSCT from 5-6/6 HLA-matched family donors: 8 received peripheral blood stem cells, 2 received bone marrow, and 1 received related cord blood transplantation. Three patients received an unrelated allograft (two 4-5/6 and one 9/10) from unrelated cord blood unit and bone marrow, respectively. Neutrophil and platelet engraftment was observed in all assessable patients (100%), achieved at median 15.5 days (range, 7 to 31) and 21 days (range, 10 to 52), respectively. Three patients received GO at dose level 1 (4.5 mg/m2 per dose), 5 at dose level 2 (6 mg/m2 per dose), 3 at dose level 3 (7.5 mg/m2 per dose), and 3 at dose level 4 (9 mg/m2 per dose). Three of 14 patients received only 1 dose of GO after alloHSCT. One patient experienced grade III transaminitis, which resolved; no grade IV transaminitis, no grade III/IV hyperbilirubinemia, or sinusoidal obstructive syndrome were observed. The second dose of GO was given at median of 143 days (range, 120 to 209) after alloHSCT. Probability of grades II to IV acute and chronic graft-versus-host disease were 21% and 33.5%, respectively. Probability of overall survival after RIC alloHSCT and GO consolidation at 1 and 5 years was 78% and 61%, respectively. Probability of 5-year event-free survival after RIC alloHSCT and GO consolidation in patients in CR1 was 78%. No dose-limiting toxicities probably or directly related to GO were observed in this cohort. This preliminary data demonstrate that RIC followed by alloHSCT and consolidation with GO appears to be safe in children and adolescents with CD33+ AML in CR1/CR2. A phase II trial is currently underway investigating this approach with a GO dose of 9 mg/m2 per dose.
authors.affiliation: Department of Pediatrics, New York Medical College, Valhalla, New York.
authors.forename: Stacey
authors.initials: S
authors.lastname: Zahler
authors.affiliation: Department of Pediatrics, Columbia University, New York, New York.
authors.forename: Monica
authors.initials: M
authors.lastname: Bhatia
authors.affiliation: Department of Pediatrics, Columbia University, New York, New York.
authors.forename: Angela
authors.initials: A
authors.lastname: Ricci
authors.affiliation: Department of Pediatrics, New York Medical College, Valhalla, New York.
authors.forename: Sumith
authors.initials: S
authors.lastname: Roy
authors.affiliation: Department of Pediatrics, New York Medical College, Valhalla, New York.
authors.forename: Erin
authors.initials: E
authors.lastname: Morris
authors.affiliation: Department of Pediatrics, New York Medical College, Valhalla, New York.
authors.forename: Lauren
authors.initials: L
authors.lastname: Harrison
authors.affiliation: Department of Pediatrics, New York Medical College, Valhalla, New York.
authors.forename: Carmella
authors.initials: C
authors.lastname: van de Ven
authors.affiliation: Department of Pediatrics, New York Medical College, Valhalla, New York.
authors.forename: Sandra
authors.initials: S
authors.lastname: Fabricatore
authors.affiliation: Department of Pediatrics, New York Medical College, Valhalla, New York.
authors.forename: Karen
authors.initials: K
authors.lastname: Wolownik
authors.affiliation: Department of Pediatrics, Mount Sinai Medical School, New York, New York.
authors.forename: Erin
authors.initials: E
authors.lastname: Cooney-Qualter
authors.affiliation: Department of Pathology, Children's Hospital of Los Angeles, Los Angeles, California.
authors.forename: Lee Ann
authors.initials: LA
authors.lastname: Baxter-Lowe
authors.affiliation: Department of Pediatrics, New York Medical College, Valhalla, New York.
authors.forename: Paul
authors.initials: P
authors.lastname: Luisi
authors.affiliation: Department of Pediatrics, New York Medical College, Valhalla, New York.
authors.forename: Olga
authors.initials: O
authors.lastname: Militano
authors.affiliation: Department of Pediatrics, Northwestern University, Chicago, Illinois.
authors.forename: Morris
authors.initials: M
authors.lastname: Kletzel
authors.affiliation: Department of Pediatrics, New York Medical College, Valhalla, New York; Departments of Medicine, Pathology, Microbiology and Immunology, and Cell Biology and Anatomy, New York Medical College, Valhalla, New York. Electronic address: Mitchell_Cairo@nymc.edu.
authors.forename: Mitchell S
authors.initials: MS
authors.lastname: Cairo
mesh_terms: D000293:Adolescent; D000617:Aminoglycosides / Q000627:therapeutic use*; D061067:Antibodies, Monoclonal, Humanized / Q000627:therapeutic use*; D000961:Antilymphocyte Serum / Q000627:therapeutic use; D002066:Busulfan / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D060830:Consolidation Chemotherapy / Q000379:methods; D004334:Drug Administration Schedule; D005260:Female; D000079982:Gemtuzumab; D006086:Graft vs Host Disease / Q000276:immunology / Q000401:mortality / Q000473:pathology / Q000517:prevention & control; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D007167:Immunotherapy / Q000379:methods*; D000922:Immunotoxins / Q000627:therapeutic use*; D015470:Leukemia, Myeloid, Acute / Q000276:immunology / Q000401:mortality / Q000473:pathology / Q000628:therapy*; D008297:Male; D019653:Myeloablative Agonists / Q000627:therapeutic use; D063268:Sialic Acid Binding Ig-like Lectin 3 / Q000276:immunology; D035781:Siblings; D016019:Survival Analysis; D019172:Transplantation Conditioning / Q000379:methods*; D014184:Transplantation, Homologous; D061349:Unrelated Donors; D014740:Vidarabine / Q000031:analogs & derivatives / Q000627:therapeutic use; D055815:Young Adult
chemical_list: D000617:Aminoglycosides; D061067:Antibodies, Monoclonal, Humanized; D000961:Antilymphocyte Serum; C571163:CD33 protein, human; D007166:Immunosuppressive Agents; D000922:Immunotoxins; D019653:Myeloablative Agonists; D063268:Sialic Acid Binding Ig-like Lectin 3; D000079982:Gemtuzumab; D014740:Vidarabine; D002066:Busulfan; C024352:fludarabine
keywords: Allogeneic stem cell transplantation; Gemtuzumab ozogamicin; Immunotherapy; Pediatric AML; Reduced-intensity conditioning