A study published in The Lancet Haematology, invesitgators found that total marrow and lymphoid irradiation in combination with high-dose cyclophosphamide and etoposide as a conditioning regimen prior to allogeneic hematopoietic cell transplantation was effective in patients with relapsed or refractory acute leukemia.
Anthony Stein, MD, of the Gehr Family Center for Leukemia Research at City of Hope in California, and colleagues, conducted the single-center, open-label, phase II study that included patients ages 16 to 60 years with acute myeloid leukemia or acute lymphoblastic leukemia.
Prior to bone marrow or peripheral blood transplant, patients received total marrow and lymphoid irradiation (2000 cGy) on days –9 to –5, etoposide 60 mg/kg on day –4, and cyclophosphamide 100 mg/kg on day –2.
Following an initial six-patient safety lead-in period that did not result in unacceptable toxicity, 106 patients received this conditioning protocol prior to HCT. A majority of patients (54%) were male and White (68%).
After a median follow-up of 1.8 months overall and 3.1 years for surviving patients, the two-year estimated progression-free survival (primary endpoint) was 34%, which the authors called “encouraging.”
The most common grade 3/4 adverse events were cytopenias (91%), metabolic disorders (78%), oral mucositis (42%), diarrhea (24%), nausea (20%), and palmar-plantar erythrodysesthesia syndrome (10%). One treatment-attributed death occurred from sinusoidal obstruction syndrome.
The authors concluded that there were few adverse events, likely “due to organ sparing by total marrow and lymphoid irradiation,” noting that this combination could be “safely delivered” to this patient cohort.
Reference
Stein A, Wang Y, Al Malki MM, et al. Total marrow and lymphoid irradiation in combination with cyclophosphamide and etoposide before haematopoietic cell transplantation for relapsed or refractory acute leukaemia: a single-centre, open-label, phase 2 trial. Lancet Haematol. 2026:S2352-3026(26)00014-1. doi:10.1016/S2352-3026(26)00014-1
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