title: Evaluation of the Pharmacokinetics and Efficacy of a Busulfan Test Dose in Adult Patients Undergoing Myeloablative Hematopoietic Cell Transplantation.
abstract: Owing to interpatient variability in busulfan exposure, therapeutic monitoring of busulfan is often used in myeloablative allogeneic transplantation to ensure that patients are near the optimal steady-state goal of 900 ng/mL. One challenge in therapeutic monitoring of busulfan is the brief course of busulfan treatment, requiring prompt analysis and dose adjustments as needed. Pharmacokinetic evaluation of a busulfan test dose before the start of the conditioning regimen would allow for all conditioning regimen doses to be given at the calculated optimized dose. An observational study was completed to evaluate the effects of a busulfan test dose of 0.9 mg/kg administered before the start of a myeloablative intravenous busulfan-based conditioning regimen. Sixty adult patients who received a busulfan conditioning regimen were reviewed, including 30 patients prior to the implementation of the busulfan test dose (pretest dose group) and 30 patients who received the busulfan test dose (posttest dose group). The primary objective was a pharmacokinetic evaluation of the percentage of patients who achieved the desired steady-state goal using the test dose strategy. The safety and efficacy of the busulfan test dose were evaluated as well. The average busulfan steady-state level after the first dose of the conditioning regimen was significantly lower in the pre-test dose group compared with the post-test dose group (660 ng/mL versus 879.9 ng/mL; P < 0.001). Compared with the post-test dose group, significantly fewer patients in the pre-test dose group were within 10% of the busulfan steady-state goal (10% versus 73.3%; P < 0.001) or within 5% of the goal (0% versus 53%; P < 0.001). Requirements for parenteral nutrition and/or patient-controlled analgesia owing to mucositis and rates of veno-occlusive disease were not significantly different between the pre-test dose group and the post-test dose group. The rates of disease relapse, mortality, and acute graft-versus-host disease were similar in the two groups. A pretransplantation busulfan test dose of 0.9 mg/kg improved the patients' ability to reach therapeutic busulfan target levels after the first conditioning dose and resulted in fewer adjustments during conditioning. The use of a busulfan test dose did not significantly increase patients' risk of mucositis or other safety outcomes.
authors.affiliation: Hematology/Oncology, Froedtert & the Medical College of Wisconsin, Milwaukee, Wisconsin.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Weil
authors.affiliation: Hematology/Oncology, Froedtert & the Medical College of Wisconsin, Milwaukee, Wisconsin.
authors.forename: Felicia
authors.initials: F
authors.lastname: Zook
authors.affiliation: Hematology/Oncology, Froedtert & the Medical College of Wisconsin, Milwaukee, Wisconsin.
authors.forename: Carolyn
authors.initials: C
authors.lastname: Oxencis
authors.affiliation: Hematology/Oncology, Froedtert & the Medical College of Wisconsin, Milwaukee, Wisconsin.
authors.forename: Angela
authors.initials: A
authors.lastname: Canadeo
authors.affiliation: Investigational Drug Services, Froedtert & the Medical College of Wisconsin, Milwaukee, Wisconsin.
authors.forename: Angela
authors.initials: A
authors.lastname: Urmanski
authors.affiliation: Hematology/Oncology, Froedtert & the Medical College of Wisconsin, Milwaukee, Wisconsin.
authors.forename: Mindy
authors.initials: M
authors.lastname: Waggoner
authors.affiliation: Biostatistics, Froedtert & the Medical College of Wisconsin, Milwaukee, Wisconsin.
authors.forename: Daniel
authors.initials: D
authors.lastname: Eastwood
authors.affiliation: Hematological Malignancies, Adult Blood and Marrow Transplant Program, Froedtert & the Medical College of Wisconsin, Milwaukee, Wisconsin.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Pasquini
authors.affiliation: Hematological Malignancies, Adult Blood and Marrow Transplant Program, Froedtert & the Medical College of Wisconsin, Milwaukee, Wisconsin.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Hamadani
authors.affiliation: Hematological Malignancies, Adult Blood and Marrow Transplant Program, Froedtert & the Medical College of Wisconsin, Milwaukee, Wisconsin. Electronic address: phari@mcw.edu.
authors.forename: Parameswaran
authors.initials: P
authors.lastname: Hari
mesh_terms: D000328:Adult; D000368:Aged; D002066:Busulfan / Q000008:administration & dosage* / Q000009:adverse effects / Q000493:pharmacokinetics*; D004305:Dose-Response Relationship, Drug; D016903:Drug Monitoring / Q000379:methods*; D005260:Female; D018380:Hematopoietic Stem Cell Transplantation / Q000379:methods; D006801:Humans; D008297:Male; D020714:Maximum Tolerated Dose; D008875:Middle Aged; D052016:Mucositis / Q000209:etiology; D019653:Myeloablative Agonists / Q000627:therapeutic use; D019172:Transplantation Conditioning / Q000379:methods; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D019653:Myeloablative Agonists; D002066:Busulfan
keywords: Allogeneic; Busulfan; Myeloablative; Transplantation