In the era of tyrosine kinase inhibitors (TKIs), hematopoietic cell transplantation (HCT) remains a valid option for the treatment of patients with chronic myeloid leukemia (CML) when both disease and transplant risk are considered, a study published in the journal Leukemia has shown.
Because TKIs represent the current treatment of choice in CML, allogeneic HCT is regarded as salvage therapy; however, there are no prospective randomized trials to confirm this concept.
Instead, the recommendations are based on positive early results of imatinib compared with interferon-α-based therapies and are partly supported by a study demonstrating HCT was associated with increased mortality.
More recently, a study showed survival of carefully selected patients with low-risk CML who underwent HCT was similar to a similar group that received imatinib.
Therefore, researchers sought to evaluate clinically relevant differences between early allogeneic HCT and best drug treatment in patients with CML who are eligible to receive either option.
For the prospective CML-study 3A, investigators enrolled 669 patients with newly diagnosed CML between July 1997 and January 2004 from 143 centers. Of those, 427 were randomly assigned to receive a matched family donor primary HCT or best available drug treatment.
Results showed that the 10-year survival probability of HCT patients was 0.76 (95% CI, 0.69 – 0.82) compared with 0.69 (95% CI, 0.61 – 0.76) with drug treatment. There was no statistically significant difference between the 2 arms, but researchers found that 10-year survival was influenced by disease and transplant risk.
Patients with a low transplant risk demonstrated superior survival compared with patients with high-risk (P < .001) and non-high-risk disease (P = .047) in the drug treatment group; however, after entering blast crisis, there was no difference in survival between HCT and no HCT.
The study further demonstrated that significantly more patients in the HCT group were in molecular remission (P = .005) and free of drug treatment (P < .001).
The authors noted that these results differ from those of the CML-study 3, which may be explained by differences in the risk profile of certain patients.
- Gratwohl A, Pfirrmann M, Zander A, et al. Long-term outcome of patients with newly diagnosed chronic myeloid leukemia: a randomized comparison of stem cell transplantation with drug treatment [published online ahead of print November 20, 2015]. Leukemia. doi: 10.1038/leu.2015.281.