The combination of clofarabine, etoposide, and cyclophosphamide shows
limited efficacy as a bridge to transplant for children with refractory
acute leukemia: Results of a monitored prospective study
Abstract
Background Clofarabine has been shown to effectively induce remission in
children with refractory leukemia. We conducted a prospective study to
explore the use of clofarabine-based chemotherapy as a
bridge-to-transplant approach. Methods Children with refractory acute
leukemia were enrolled to receive two induction courses of clofarabine,
etoposide, and cyclophosphamide (CloEC). Responding patients were
scheduled for T-cell depleted haploidentical hematopoietic stem cell
transplantation (HSCT). The primary objective was to improve survival by
achieving sufficient disease control to enable stem cell
transplantation. Secondary objectives were to evaluate safety and
toxicity. Results Seven children with active disease entered the study.
Two children responded to induction courses and underwent
transplantation. Five children did not respond to induction: one died in
progression after the first course; two received off-protocol
chemotherapy and were transplanted; and two succumbed to progressive
leukemia. All transplanted children engrafted and no acute skin
graft-versus-host disease > grade I was observed. One child
is alive and well 7.5 years after the first CloEC course. One child
developed fulminant adenovirus hepatitis and died in continuous complete
remission 7 months after start of induction. Two children relapsed and
died 6.5 and 7.5 months after enrollment. Infection was the most common
toxicity. Conclusions CloEC can induce responses in some patients with
refractory acute leukemia but is highly immunosuppressive, resulting in
substantial risk of life-threatening infections. In our study,
haploidentical HSCT was feasible with sustained engraftment. No
clinically significant organ toxicity was observed. Also, repeating
CloEC probably does not increase the chance of achieving remission.