Do high and low intensity treatments have similar effectiveness in CML?

This study compared the effectiveness of regular myeloablative conditioning (MAC; chemotherapy that kills cells in the bone marrow, including cancer cells before a transplant) with reduced-intensity conditioning (RIC) in the treatment of chronic myeloid leukemia. Researchers found that RIC had similar effectiveness and less risk of transplant rejection than MAC.

Chronic myeloid leukemia (CML) is a cancer of the bone marrow. It is frequently linked to abnormal genes and can lead to abnormal immune cells. It is often treated by destroying the cancer cells (myeloablative conditioning) and replacing them with normal healthy donor cells (hematopoietic cell transplantation or HCT). However, MAC can be associated with an increased risk of side effects. A reduced intensity therapy (RIC) is an alternative, particularly for frail patients. The safety and effectiveness of RIC compared to MAC in patients with CML are still under investigation.

1395 patients with CML who received a HCT were included in the study. 1204 received MAC and 191 received RIC treatment before the HCT. Overall survival, leukemia-free survival, and side effects were assessed.

No significant difference in survival was found between the two treatments. Overall survival at 5 years was 53% in each group. The 5-year leukemia-free survival was also similar in the MAC group (44%) and the RIC group (43%).

Patients who received RIC treatment were 85% more likely than the MAC group to experience a return of disease early (in the first 5 months) after the HCT. However, the long-term (5-year) risk of relapse was similar in the MAC group (26%) and the RIC group (25%). The RIC group had 23% less risk of transplant rejection compared to the MAC group.

The study concluded that RIC treatment may be a suitable alternative treatment for patients with CML.

The RIC group had a small number of patients compared to the MAC group This may have affected the results.