BUSULFEX (busulfan)
Busulfex is indicated for use in combination with cyclophosphamide as a conditioning regimen prior to allogeneic hematopoietic progenitor cell transplantation for chronic myelogenous leukemia (CML). It serves as a myeloablative agent, depleting the patient's bone marrow and malignant cell population to facilitate the successful engraftment of donor hematopoietic stem cells.
How BUSULFEX Works
Busulfan is a bifunctional alkylating agent. In aqueous media, the molecule releases methanesulfonate groups to produce reactive carbonium ions. These ions alkylate DNA, leading to the formation of DNA cross-links. This damage interferes with DNA replication and transcription, resulting in cytotoxicity and the necessary depletion of hematopoietic cells prior to transplant.
Development Insights
Details
- Status
- Prescription
- First Approved
- 1999-02-04
- Routes
- INJECTION
- Dosage Forms
- INJECTABLE
BUSULFEX Approval History
What BUSULFEX Treats
1 indicationsBUSULFEX is approved for 1 conditions since its original approval in 1999. These indications span multiple therapeutic areas including oncology, immunology, and more.
- Chronic Myelogenous Leukemia
BUSULFEX Boxed Warning
MYELOSUPPRESSION BUSULFEX (busulfan) Injection causes severe and prolonged myelosuppression at the recommended dosage. Hematopoietic progenitor cell transplantation is required to prevent potentially fatal complications of the prolonged myelosuppression [see Warnings and Precautions (5.1) ]. WARNING: MYELOSUPPRESSION See full prescribing information for complete boxed warning. Causes severe and prolonged myelosuppression. ( 5.1 ) Hematopoietic progenitor cell transplantation is required to preve...
WARNING: MYELOSUPPRESSION BUSULFEX (busulfan) Injection causes severe and prolonged myelosuppression at the recommended dosage. Hematopoietic progenitor cell transplantation is required to prevent potentially fatal complications of the prolonged myelosuppression [see Warnings and Precautions (5.1) ]. WARNING: MYELOSUPPRESSION See full prescribing information for complete boxed warning. Causes severe and prolonged myelosuppression. ( 5.1 ) Hematopoietic progenitor cell transplantation is required to prevent potentially fatal complications of the prolonged myelosuppression. ( 5.1 )
BUSULFEX Competitive Set
ProThree rings of competition based on shared molecular targets and treated indications.
MoA expansion candidates
Same target(s), different indications — where else is this mechanism being explored?
Indication competitors
Same indication, different mechanism — what else might this patient receive?
Filters applied: drops same-active-ingredient (505(b)(2) reformulations), route-mismatch (topical vs systemic), and cross-therapeutic-area matches in same-indication rings.
What's emerging in BUSULFEX's indications
See all emerging drugs →Phase 3 candidates targeting molecules with no FDA-approved drug, in indications BUSULFEX treats. First-in-class if their pivotal trials read out positive.
Drugs Similar to BUSULFEX
FDA-approved drugs for similar conditions. Compare mechanisms and indications to understand treatment alternatives.
Clinical Trial Registry
194 trials| Trial | Sponsor ID | Phase | Status | Title |
|---|---|---|---|---|
| NCT05564390 | NCI-2022-07006 NCI-2022-07006, MYELOMATCH | Ph 2 | recruiting | MYELOMATCH: A Screening Study to Assign People With Myeloid Cancer to a Treatment Study or Standard of Care Treatment Within myeloMATCH (MyeloMATCH Screening Trial) |
| NCT06954987 | NCI-2025-03015 NCI-2025-03015, MM3TCT-A03 | Ph 2 | not yet recruiting | Venetoclax or Placebo in Combination With Reduced-Intensity Conditioning Hematopoietic Cell (Bone Marrow/Blood Stem Cell) Transplant and as Maintenance Therapy After Transplant in Patients With Acute Myeloid Leukemia (A MyeloMATCH Treatment Trial) |
| NCT02629120 | 160032 16-I-0032 | Ph 1, Ph 2 | active not recruiting | High Dose Peripheral Blood Stem Cell Transplantation With Post Transplant Cyclophosphamide for Patients With Chronic Granulomatous Disease |
| NCT07524530 | 10002233 002233-C | Ph 2 | not yet recruiting | Stem Cell Transplantation for Participants With Germline RUNX1 Associated Blood Cancers |
| NCT06996119 | 23822 NCI-2025-03603, 23822 | Ph 1 | recruiting | Emapalumab With Post-Transplant Cyclophosphamide, Tacrolimus and Mycophenolate Mofetil for the Prevention of Graft-versus-Host Disease After Donor Reduced-Intensity Hematopoietic Cell Transplant |
| NCT06079879 | 3543-006 2023-504865-21-00, IMG-7289-CTP-301 | Ph 3 | recruiting | A Study of Bomedemstat (IMG-7289/MK-3543) Compared to Best Available Therapy (BAT) in Participants With Essential Thrombocythemia and an Inadequate Response or Intolerance of Hydroxyurea (MK-3543-006) |
| NCT05027945 | 10000404 000404-C | Ph 2 | recruiting | A Phase II Study of Allogeneic Hematopoietic Stem Cell Transplant for Subjects With VEXAS (Vacuoles, E1 Enzyme, X-linked, Autoinflammatory, Somatic) Syndrome |
| NCT04872595 | 21-193 | Ph 2 | active not recruiting | A Modified Dose of Rabbit Anti-thymocyte Globulin (rATG) in Children and Adults Receiving Treatment to Help Prepare Their Bodies for a Bone Marrow Transplant |
| NCT05463133 | 10000977 000977-I | Ph 1, Ph 2 | recruiting | Allogeneic Hematopoietic Stem Cell Transplantation for Chronic Granulomatous Disease (CGD) With an Alemtuzumab, Busulfan and TBI-based Conditioning Regimen Combined With Cytokine (IL-6, +/- IFN-gamma) Antagonists |
| NCT07566377 | 26-168 | Ph 2 | recruiting | Cord Blood Transplantation in Children and Young Adults With Blood Cancer |
| NCT06506461 | SAGES1 U01HL163983 | Ph 1 | recruiting | Gene Editing For Sickle Cell Disease |
| NCT02727803 | 2015-0313 NCI-2016-00584, 2015-0313 | Ph 2 | recruiting | Personalized NK Cell Therapy in CBT |
| NCT06158828 ABCD-NK | 202401147 | Ph 1, Ph 2 | recruiting | Pilot Study of Memory-like Natural Killer (ML NK) Cells After TCRαβ T Cell Depleted Haploidentical Transplant in AML |
| NCT04339777 | 200070 20-C-0070 | Ph 2 | recruiting | Allogeneic Hematopoietic Stem Cell Transplant for Patients With Inborn Errors of Immunity |
| NCT07565220 | HCC 26-008 | Ph 1 | not yet recruiting | Thiotepa-based Conditioning Regimen With De-escalated Post-graft Cyclophosphamide for Allogeneic Stem Cell Transplantation in Hematologic Malignancies |
| NCT07113743 | 10000186 000186-I | Ph 1, Ph 2 | enrolling by invitation | Part B- G1X-CGD (Lentiviral Vector Transduced CD34+ Cells) in Patients With X-Linked Chronic Granulomatous Disease |
| NCT01306019 | 110007 11-I-0007 | Ph 1, Ph 2 | recruiting | Lentiviral Gene Transfer for Treatment of Children Older Than Two Years of Age With X-Linked Severe Combined Immunodeficiency (XSCID) |
| NCT05327023 | 10000489 000489-C | Ph 1, Ph 2 | recruiting | Donor Lymphocyte Infusion After Allogeneic Hematopoietic Cell Transplantation for High-Risk Hematologic Malignancies |
| NCT01857934 results posted | NB2012 NCI-2013-00034 | Ph 2 | completed | Therapy for Children With Advanced Stage Neuroblastoma |
| NCT04859946 | 2020-0971 NCI-2021-02784, 2020-0971 | Ph 2 | active not recruiting | Itacitinib for the Prevention of Graft Versus Host Disease |
| NCT02250937 | 2014-0431 NCI-2014-02324, 2014-0431 | Ph 2 | active not recruiting | Venetoclax and Sequential Busulfan, Cladribine, and Fludarabine Phosphate Before Donor Stem Cell Transplant in Treating Patients With Acute Myelogenous Leukemia or Myelodysplastic Syndrome |
| NCT01384513 results posted | 11D.247 2011-31, JT 1795 | Ph 2 | completed | A Two-Step Approach to Reduced Intensity Bone Marrow Transplant for Patients With Hematological Malignancies |
| NCT04384692 | RG1006507 NCI-2020-01626, 10093 | Ph 2 | active not recruiting | Peritransplant Ruxolitinib for Patients With Primary and Secondary Myelofibrosis |
| NCT04547049 | NFD-001 | Ph 3 | active not recruiting | A Study Comparing Haploidentical Hematopoietic Stem Cell Transplantations (HSCTs) From Young Non-first-degree and Older First-degree Donors in Hematological Malignancies |
| NCT05735717 | 2021LS061 | Ph 2 | recruiting | MT2021-08T Cell Receptor Alpha/Beta Depletion PBSC Transplantation for Heme Malignancies |
| NCT06325709 | 10001580 001580-I | Ph 1, Ph 2 | recruiting | Base Editing for Mutation Repair in Hematopoietic Stem & Progenitor Cells for X-Linked Chronic Granulomatous Disease |
| NCT02251821 results posted | 9033 NCI-2014-01882, 9033 | Ph 2 | completed | JAK Inhibitor Before Donor Stem Cell Transplant in Treating Patients With Primary or Secondary Myelofibrosis |
| NCT06959771 | 10002385 002385-I | Ph 1, Ph 2 | recruiting | Base Editing Hematopoietic Stem Cell and T Cell Gene Therapy for CD40L-HyperIgM Syndrome: Single Patient Study |
| NCT04904588 ACCESS | ACCESS | Ph 2 | active not recruiting | HLA-Mismatched Unrelated Donor Hematopoietic Cell Transplantation With Post-Transplantation Cyclophosphamide |
| NCT04644016 | 20-480 | Ph 2 | recruiting | Cord Blood Transplant in Children and Young Adults With Blood Cancers and Non-malignant Disorders |
| NCT03970096 | RG1005364 9749, NCI-2019-03188 | Ph 2 | recruiting | Graft Versus Host Disease-Reduction Strategies for Donor Blood Stem Cell Transplant Patients With Acute Leukemia or Myelodysplastic Syndrome (MDS) |
| NCT06872333 | 2024LS140 | Ph 2 | recruiting | Allo HSCT for High Risk Hemoglobinopathies |
| NCT06345495 | 2023-0899 NCI-2024-02814 | Ph 2 | recruiting | High Dose Ruxolitinib and Allogeneic Stem Cell Transplantation in Myelofibrosis Patients With Splenomegaly |
| NCT05565105 | 2021-KOE-001 | Ph 2 | not yet recruiting | CD34+ Transplants for Leukemia and Lymphoma |
| NCT05617625 | 2021-KOE-002 | Ph 2 | suspended | CD34+ Enriched Transplants to Treat Myelodysplastic Syndrome |
| NCT07441967 | IIT2025140 | Ph 2 | not yet recruiting | The Safety and Efficacy of the Regimen of Thiotepa + Fludarabine +Granulocyte Colony-Stimulating Factor+ Cytarabine + Busulfan in Single Unrelated Umbilical Cord Blood Transplantation |
| NCT03126916 | ANBL1531 NCI-2016-01734, ANBL1531 | Ph 3 | recruiting | Testing the Addition of 131I-MIBG or Lorlatinib to Intensive Therapy in People With High-Risk Neuroblastoma (NBL) |
| NCT05170828 | PRESERVE | Ph 1 | withdrawn | Cryopreserved MMUD BM With PTCy for Hematologic Malignancies |
| NCT04708054 | 2020-0790 NCI-2020-13919, 2020-0790 | Ph 2, Ph 3 | recruiting | Venetoclax to Improve Outcomes of Fractionated Busulfan Regimen in Patients With High-Risk AML and MDS |
| NCT07228624 | RG1125655 NCI-2025-07728, FHIRB0020989 | Ph 2 | recruiting | Ruxolitinib Before, During and After Hematopoietic Cell Transplant in Older Patients With Myelofibrosis and Myelodysplastic Syndrome/Myeloproliferative Neoplasm Overlap Syndromes |
| NCT06207799 | 2023-0448 NCI-2024-00110 | Ph 2 | recruiting | Pre-transplant Purging and Post-transplant MRD-guided Maintenance Therapy With Elranatamab in Patients With High-risk Multiple Myeloma |
| NCT03619551 CSIDE | PBMTC NMD1801 | Ph 2 | active not recruiting | Conditioning SCID Infants Diagnosed Early |
| NCT06851767 | 10002273 002273-I | Ph 1, Ph 2 | enrolling by invitation | Base-Edited Hematopoietic Stem/Progenitor Cell X-Linked Severe Combined Immunodeficiency Gene Therapy |
| NCT02861417 | 2016-0137 NCI-2017-00614, 2016-0137 | Ph 2 | active not recruiting | Busulfan, Fludarabine Phosphate, and Post-Transplant Cyclophosphamide in Treating Patients With Blood Cancer Undergoing Donor Stem Cell Transplant |
| NCT03538899 | 17-22799 CLIN2-10830, CLIN2-17127 | Ph 1, Ph 2 | recruiting | Autologous Gene Therapy for Artemis-Deficient SCID |
| NCT01625351 | RADIANT NCI-2012-00588 | Ph 1 | completed | A Study of CD45RA+ Depleted Haploidentical Stem Cell Transplantation in Children With Relapsed or Refractory Solid Tumors and Lymphomas |
| NCT06001385 OPTIMIZE | OPTIMIZE | Ph 2 | active not recruiting | HLA-Mismatched Unrelated Donor Peripheral Blood Stem Cell Transplantation With Reduced Dose Post Transplantation Cyclophosphamide GvHD Prophylaxis |
| NCT03579875 | 2016LS161 MT2017-17 | Ph 2 | recruiting | Alpha/Beta TCD HCT in Patients With Inherited BMF Disorders |
| NCT05917405 FLUCLORIC | RC22_0524 | Ph 2 | recruiting | Study Comparing the Efficacy of 2 RIC Regimens (Clofarabine vs Fludarabine) in Adults With AML Eligible to Allo-SCT |
| NCT06252870 CY-MET-RIC | RC23_0286 | Ph 2 | recruiting | Study Testing Two Conditioning Regimen With a Single Prophylaxis of GVHD by Cyclophosphamide and Methotrexate Post-transplant in Patients Eligible for Matched-donor Allograft Transplantation |
Showing 50 of 194 trials
Active Pipeline
Ongoing clinical trials by development phase
Key Completed Trials
Completed studies with published results, ranked by significance
Trial Timeline
Full development history with FDA approval milestones
Understanding FDA Approval Types
| Count | Type | What it means |
|---|---|---|
| - | ORIG | Original approval - drug first enters market |
| - | SUPPL - Efficacy | New indication (new disease/condition approved) |
| - | SUPPL - Labeling | Label text changes (warnings, dosing updates) |
| - | SUPPL - Manufacturing | Production changes (new facility) |
| - | SUPPL - Chemistry | Formulation changes (new dosage strength) |
Green lines in the timeline show ORIG and Efficacy approvals - the clinically meaningful milestones.
BUSULFEX FDA Label Details
Indications & Usage
FDA Label (PDF)BUSULFEX is indicated for the treatment of Chronic Myelogenous Leukemia.
WARNING: MYELOSUPPRESSION BUSULFEX (busulfan) Injection causes severe and prolonged myelosuppression at the recommended dosage. Hematopoietic progenitor cell transplantation is required to prevent potentially fatal complications of the prolonged myelosuppression [see Warnings and Precautions (5.1) ]...
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Data Sources
Data sourced from official FDA and NIH databases. Click links to verify on original sources.
How We Calculate These Metrics
Trial Activity Stage
Measures the current development activity pattern based on trial phases, status, and trends. Important: This measures R&D activity, not commercial lifecycle.
Trial statuses: "Active" means recruiting or ongoing. "Completed" means reached planned endpoint. "Terminated" means stopped early—often due to safety, efficacy, or business reasons.
- Growth: High proportion of early-phase trials (Phase 1/2), active development
- Expansion: Significant Phase 3 activity, approaching or pursuing approvals
- Mature: Substantial Phase 4 post-marketing studies
- Stable: Mixed phase distribution, steady development
- Declining: Low active trial ratio, reduced R&D investment