The Outcome of Infants with Acute Lymphoblastic Leukemia Treated with Interfant-99 Protocol

Objective: The Outcome of Infants with Acute Lymphoblastic Leukemia Treated with Interfant-99 Protocol

Materials and Methods: In this retrospective analytical study, all newly diagnosed infants with ALL who were treated with Interfant-99 protocol from 2004 to 2014 in Ali-Asghar Children's Hospital in Tehran were included. Demographic data including age at diagnosis, sex, initial WBC, Hb and platelet count, flow cytometric diagnosis, cytogenetic findings, follow-up duration, and their outcome was extracted from patients' medical records. All the above data were analyzed by SPSS 23 software.

Results: 11 infants with ALL (5 girls and 6 boys) were included in the study. Mean and median age at diagnosis of all enrolled patients were 7.20 (std. deviation = 1.78; range = 3.57-9.37) and 7.90 months, respectively. 5 of the 11 patients had t (4; 11) and all of them were Pro-B ALL. The mean initial WBC in patients with this translocation was significantly higher than the others (193400 vs. 49166), and this difference was statistically significant (P = 0.004) despite the small number of patients under study. None of the patients had CNS involvement or mediastinal mass at diagnosis. Three patients relapsed, two of whom had isolated CNS relapse. Finally, one of them recovered completely as chemotherapy continued, another suffered a bone marrow relapse and eventually died, and a third suffered a bone marrow relapse and died about 10 months after relapse. The median follow-up of all patients was 53.83-mo. The estimated 5-yr overall survival of patients was 68.60% ± 15.10, and their Estimated 5-yr event-free survival was 21.20%±45.70. Infection was the most common complication during treatment that was manageable.

Conclusion: The Interfant-99 protocol appeared to improve the outcome of infants with ALL even with t (4; 11), with manageable complications. However, its implementation in developing countries has problems due to the small number of rooms suitable for heavy chemotherapy, and the dose of drugs that should be modified. It is worth noting that proving this requires a comprehensive prospective study with an appropriate sample size.