Novel tyrosine kinase inhibitor therapy before allogeneic stem cell transplantation in patients with chronic myeloid leukemia - No evidence for increased transplant-related toxicity

BACKGROUND. Patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT) for chronic myeloid leukemia (CML) are increasingly likely to have received a novel tyrosine kinase inhibitor (NTKI) after failing imatinib mesylate. It is unknown whether the use of these NTKIs before HSCT increases transplant-related toxicity. METHODS. The outcome of 12 patients with CNIL (I in chronic phase, 6 in the accelerated phase, and 5 in the blastic phase) who received dasatinib (n = 2), nilotinib (n = 7), or both (n = 3) before HSCT were retrospectively analyzed. RESULTS. The median time on treatment was 134 days, and the median time from the end of NTKI therapy to HSCT was 34 days. The preparative regimen was ablative in 8 patients and nonablative in 4. All patients engrafted within 13 days. There was no significant early transplant-related toxicity. One patient developed secondary graft failure after 6 months from the first HSCT that required a second HSCT Acute and chronic graft-versus-host disease (GVHD) was observed in 7 and 6 patients, respectively. Nine patients achieved a molecular response: 4 complete and 5 major (quantitative reverse transcriptase-polymerase chain reaction <0.05%). Three patients had disease progression by Day 30 after HSCT. Two patients developed disease recurrence after a median of 12 months. After a median follow-up of 10 months, 7 patients were alive in molecular response and 5 patients had died, 4 of disease progression and I of extensive chronic GVHD. CONCLUSIONS. Previous treatment with NTKI did not increase transplant-related toxicity in this preliminary experience. Further follow-up and a larger number of patients will be necessary to confirm these observations.