The Effects of Campath 1H upon Graft-Versus-Host Disease, Infection, Relapse, and Immune Reconstitution in Recipients of Pediatric Unrelated Transplants

Graft-versus-host disease (GVHD) is a cause of serious morbidity and mortality in >50% of recipients of unrelated hematopoietic stem cell transplantation (HSCT). We performed a trial using Campath 1 H pre- and post-HSCT in an attempt to decrease the incidence of GVHD without increasing the risk of infection or relapse. Patients were retrospectively compared to a population of patients who received antithymocyte globulin (ATG) pre- and post-HSCT. Twenty-seven patients were evaluated for this study. Fourteen patients received Campath 1H and 13 patients received ATG. Demographics of patients who received Campath 1H consisted of 9 males and 5 females, with a median age of 13 years (3-17.8 years). Thirteen patients received unrelated bone marrow and 1 patient received unrelated PBSC. Demographics of patients receiving ATG consisted of 9 males, 4 females with a median age of 7.4 years (21 months-19 years). Twelve patients received unrelated bone marrow and 1 patient received unrelated PBSC. Diagnoses were similar between the 2 groups. Patients who received Campath1H received a total dose of 52 mg/m(2) pre-HSCT and 20 mg/m(2) post-HSCT. Patients who received ATG received a total dose of 60 mg/kg pre-HSCT and 100 mg/kg post-HSCT. GVHD prophylaxis and supportive care measures were similar in both groups, including aggressive antimicrobial therapy. There was a significant difference in the incidence of severe (grade III and grade IV) GVHD between the 2 groups (Campath 0 of 14 versus ATG 6 of 13, P = .006). Among the patients who were transplanted for leukemia, there was no significant difference between the 2 groups in terms of relapse (Campath 2 of 14 versus ATG 4 of 9, P = 0.16). The 100-day survival between the 2 groups was not significantly different. Patients receiving Campath 1H had the presence of CD3(+) T cells (>30 cells/mL) in their peripheral blood later than in those who received ATG (64.5 days Campath 1H versus 27days ATG, P = .001). The median time to the development of a normal PHA response occurred later in the Campath 1H arm (283 days(Campath 1H versus 88 days ATG, P = .0001). The median time to an antigen specific response also occurred later in those receiving Campath 1H (365 days Campath 1H versus 150 days ATG, P = .004). There was no significant difference between the 2 groups in terms of fungal or viral infections. Campath 1H is effective in decreasing the incidence of GVHD without increasing the risk of relapse. Although there is a significant delay in immune reconstitution, there was no increase in infectious complications or relapse in recipients of Campath 1H. Further studies are warranted to assess if a lack of difference in infection rates are still demonstrated in larger cohorts.