Does donor type and melphalan dose impact outcomes for patients with lymphoma who receive a stem cell transplant?

This study aimed to investigate the impact of donor type and melphalan (Alkeran) dose on transplant outcomes for patients with lymphoma.

This study concluded that different donor types and melphalan doses have similar outcomes for these patients.

Allogenic hematopoietic stem cell transplant (allo-HSCT) is a potentially curative option for patients with lymphoma. Allo-HSCT is a procedure where the patient receives blood-forming stem cells from a non-identical donor such as a sister or brother. Graft versus host disease (GVHD) can occur after allo-HSCT. It occurs when the stem cells view the body as foreign and begin to attack it.

Fludarabine-Melphalan (FM) is a reduced intensity conditioning (RIC) regime for patients who receive an allo-HSCT. It uses lower doses of chemotherapy and aims to improve the success of allo-HSCT.

It is not known what impact the dose of FM and donor type have on the outcomes for patients with lymphoma treated with FM-alloHSCT.   

This study involved 186 patients with lymphoma. All patients received allo-HSCT with FM-RIC. 25 patients received stem cells from haploidentical donors (HD). These donors are half matched to the patient and are usually family members. 98 patients received stem cells from matched unrelated donors (MUD). 63 patients received stem cells from matched related donors (MRD). Patients received 160mg fludarabine in combination with melphalan either 140mg (FM140) or 100mg (FM100).

Engraftment (where the stem cells start to grow and make new blood cells) was 92% for the HD group, 89% for the MUD group and 98% for the MRD group. At 6 months, acute GVHD occurred in 4% of the HD group, 14% of the MUD and 8% of the MRD groups. After 3 years, chronic GVHD occurred in 5% of the HD group, 16% of the MUD and 26% of the MRD groups. 

After 3 years, 15% of HD patients, 21% of MUD and 39% of MRD had relapsed. At 3 years, progression-free survival (survival without the disease getting worse) was 59% for HD, 44% for MUD and 46% for MRD groups. At 3 years, overall survival was 52% for HD patients, 54% for MUD and 67% for MRD patients. No differences were seen in the 3-year survival for FM100 and FM140 patients.

This study concluded that HD transplants have similar outcomes when compared to matched transplants in patients with lymphoma. It was also concluded that FM100 is as effective as FM140.