What factors are associated with improved outcomes for patients with Philadelphia chromosome positive acute lymphoblastic leukemia undergoing allogeneic transplantation?

This study aimed to investigate allogeneic blood or marrow transplantation (alloBMT) with post-transplant cyclophosphamide (PTCy; Cytoxan) in patients with Philadelphia chromosome positive (Ph+) acute lymphoblastic leukemia (ALL).  

This study concluded that patients alloBMT with PTCy in first complete remission (CR1) leads to good outcomes, particularly in patients first treated with dasatinib (Sprycel).

AlloBMT involves taking healthy stem cells from the blood or bone marrow of a donor to replace diseased or damaged bone marrow in a cancer patient. Before an alloBMT, the patients received a conditioning regimen. This destroys patients' cancer cells. The conditioning regimen can destroy cancer cells only (non-myeloablative; NMA) or can destroy all the bone marrow (myeloablative; MA).

AlloBMT is the standard treatment for adults with Ph+ ALL in CR1. CR1 is when the patient is in remission after the first treatment. Ph+ means that patients have a genetic abnormality that makes white blood cells divide faster. Tyrosine kinase inhibitors (TKIs) such as imatinib (Gleevec) and dasatinib are a type of targeted therapy that can be used in patients with Ph+ leukemia.

After an alloBMT, a common complication is graft-versus-host-disease (GVHD). GVHD is when the transplanted cells attack the patients' healthy tissues. PTCy can be used to prevent this complication. What factors are associated with better outcomes for patients with Ph+ ALL who undergo alloBMT with PTCy remain unknown.

This study involved 81 adult patients with Ph+ ALL who received alloBMT using PTCy. 85% of transplants were performed in CR1 and 15% were performed in second or greater remission (CR2+). 91.4% of patients had TKI treatment post-transplant.  

Overall, 56% of all patients were alive without a relapse after 5 years. For patients in CR1, the 5-year relapse-free survival (RFS) rate was 66%. Overall, 77.6% of the patients transplanted in CR1 were alive after 5 years.

Patients who received alloBMT in CR1 and did not have minimal residual disease (MRD – a small amount of cancer cells left) before transplant had improved RFS. Also, patients who were treated with dasatinib before alloBMT had higher RFS at 5 years (83%) compared to those who received imatinib (49.9%) and nilotinib (Tasigna; 62.5%).

Patients who had a transplant from a half-matched donor after a NMA conditioning regimen tended to have better outcomes compared to those who had a 100% matched transplant after a MA conditioning regimen.

The occurrence of moderate to severe GVHD at 1 year was 9% and at 2 years was 8%. 

This study concluded that patients with Ph+ ALL who undergo alloBMT with PTCy after NMA in CR1, who were first treated with dasatinib had favorable outcomes.

This study used information from a database. Some information might have been incomplete.