survival probabilities for patients with discrete and continuous
baseline risks were evaluated using Kaplan-Meier
estimates; patients who were lost to follow-up were counted
as censored. Median follow-up was determined by the
reverse censoring method. The numerical results were computed
using GraphPad Prism (GraphPad, CA, USA).
Results
A total of 26 patients with SAA were treated with rabbit
ATG/CsA. The median follow-up for the cohort was 4.3 years
(interval: 0.02-12.2). The median age was 8.1 years (range:
1.6-15). The absolute neutrophil count was less than 0.2
x 109/L at presentation in 14 (53.8%) and less than 0.5 x
109/L in 12 (46.2%) patients. In 92.3% of cases, there was
no apparent precipitating event (idiopathic SAA), and two
patients (7.7%) had SAA following seronegative hepatitis.
The interval between diagnosis and start of treatment was a
median of 75.7 days (range: 7-300 days). Additional patient
characteristics are shown in Table 1.
The overall response rate at six months was 34.6% (95%
CI: 16%-53%). Three patients responded between six and
12 months resulting in a response rate of 46.2% (95% CI:
27%-65%) at this time period. The cumulative incidence of
relapse was 26.5% (95% CI: 1.4%-66%) at five years (Fig. 1,
Table 1 Demographic and hematological characteristics.
Patient characteristics Number of patients
(n = 26)
Male/ female 14/12 (53.8% / 46.2%)
Median age at diagnosis, years 8.1 (1.6-15)
Cause of aplastic anemia
Idiopatic 24 (92.3%)
Associated hepatitis 2 (7.7%)
Severity of disease at diagnosis
Very severe (neutrophil
count < 0.2 x 109/L)
14 (53.8%)
Severe (neutrophil count <
0.5 x 109/L)
12 (46.2%)
Median time between
diagnosis and treatment
initiation, days
75.7 (7-300)
Response to treatment at six months
Complete response 3 (11.6%)
Partial response 6 (23.0%)
No response 17 (65.4%)
Relapse 4 (15.0%)
Clonal evolution (monosomy 7) 2 (7.6%)
Outcome
Alive with transfusion
independency
16 (61.6%)
Alive with transfusion
dependency
4 (15.4%)
Dead 6 (23.0%)
Median time of follow-up,
years
4.3 (0.02---12.2