Umbilical cord blood transplantation improved juvenile myelomonocytic leukemia outcomes

Early diagnosis and HLA-matched umbilical cord blood transplantation were associated with improved survival in a cohort of children with juvenile myelomonocytic leukemia, according to results of a retrospective analysis.

The investigation included 110 children. Median age at diagnosis was 1.4 years (range, 0.1-6.4).

The children were given a single-unit, unrelated donor umbilical cord blood transplantation. Median age at transplantation was 2.2 years (range 0.5-7.4).

Chemotherapy had been administered to 88 patients before transplantation. Twenty-four patients underwent splenectomy before transplantation.

The most frequently observed cytogenetic abnormality was monosomy of chromosome 7, which occurred in 24% of the study population. Eighty of the 88 patients (90.9%) received myeloablative conditioning. Cyclosporine plus steroids was the most frequently used method of graft-versus-host disease prophylaxis.

Clinicians successfully matched units and patients for HLA in 16% of the cohort; 43% of patients had one HLA disparity, and 35% had either two or three HLA disparities.

The median number of nucleated cells infused was 7.1x10⁷/kg (range 1.7-27.6), according to researchers.

Median follow-up was 64 months (range, 14-174).

The 5-year cumulative incidence of transplant-associated death was 22%. At that time point, researchers observed a 33% rate of transplant-related relapse. DFS at 5 years was 44%.

Multivariable analysis results indicated that age younger than 1.4 years at diagnosis predicted improved DFS (HR=0.42; P=.005). Other factors that predicted better DFS were zero or one HLA disparities in the donor/recipient pair (HR=0.4; P=.009) and karyotype other than monosomy 7 (HR=0.5; P=.02).

Umbilical cord blood transplantation may cure a “relevant proportion” of children with this disease, the researchers concluded.

“Since disease recurrence remains the major cause of treatment failure, strategies to reduce relapse incidence are warranted,” they wrote.

Disclosure: The researchers report no relevant financial disclosures.