Infectious complications associated with alemtuzumab use for allogeneic hematopoietic stem cell transplantation: comparison with anti-thymocyte globulin.

OBJECTIVES: To evaluate the incidence of infectious complications after receiving alemtuzumab as part of a conditioning regimen for allogeneic hematopoietic stem cell transplantation (HSCT) in Korean patients.

METHODS: From November 2004 to January 2006, 12 patients who received alemtuzumab-based conditioning regimens for allogeneic HSCT were evaluated retrospectively until death or until the end of the follow-up in July 2007; they were compared with 18 patients who received rabbit anti-thymocyte globulin (ATG)-containing conditioning regimens from January 2002 to January 2006.

RESULTS: Post-engraftment infections occurred more frequently in the alemtuzumab recipients than in the ATG recipients; the mean number of infections, excluding cytomegalovirus (CMV) infections, per patient during the follow-up period was 2.6+/-1.4 vs. 1.0+/-0.8 (P=0.003), respectively. Although there was no statistical difference in the cumulative incidence of CMV infection between the 2 groups (91.7% vs. 55.6%, P=0.381), the alemtuzumab recipients had a higher incidence of CMV diseases (41.6% vs. 0%, P=0.0006) and a higher recurrence rate of CMV infection (90.0% vs. 27.3%, P=0.008) than did the ATG recipients, irrespective of the dose of alemtuzumab. Hemorrhagic cystitis (HC) (66.7% vs. 16.7%, P=0.009) and BK virus-associated HC (41.7% vs. 5.6%, P=0.026) developed more frequently in the alemtuzumab recipients. The all-cause mortality rate was not significantly different between the alemtuzumab and the ATG recipients (75% vs. 55.6%, P=0.28).

CONCLUSION: Alemtuzumab recipients had a high incidence of CMV disease as well as BK virus-associated HC compared with the ATG recipients. The dose of alemtuzumab should be tailored to patients' risk; in addition, the implementation of the appropriate prophylaxis for CMV and early detection strategies for BK virus are recommended.