Experience with generic pegylated L-asparaginase in children with acute lymphoblastic leukemia and monitoring of serum asparaginase activity

Background: Pegylated asparaginase (P-Asp) though integral to acute lymphoblastic leukemia (ALL) therapy is often not accessible to patients in developing countries. We share our clinical experience with generic P-Asp along with monitoring of asparaginase activity. Methods: In this prospective observational study, patients 18years of age with ALL were assigned to receive either generic P-Asp or native asparaginase (N-Asp) in a non-randomized manner. Treatment protocol was based on ALL BFM-95 backbone. The dose of P-Asp was 1500IU/m(2) by intravenous route during induction (Ia) and re-induction (IIa) phase of therapy. Results: N-Asp or P-Asp was administered to 52 and 54 of the 106 eligible patients respectively. Demographic and disease characteristics were comparable in both arms. The mean trough levels for N-Asp and P-Asp were 156.87 +/- 22.35IU/L and 216.03 +/- 73.40IU/L, respectively (p value <0.001) and all patients achieved therapeutic levels during Ia. Incidence of asparaginase-attributable toxicity was similar in the two arms in both phases of treatment, although hospitalization due to noninfectious causes was more common in P-Asp arm during Ia (13% versus 0%, p value, 0.01). Clinical hypersensitivity and silent inactivation were not observed during Ia while these occurred in 13% and 5% of patients in the N-Asp arm and P-Asp arms of IIa, respectively. The 2-year event free survival for P-Asp and N-Asp groups was 84% and 80.7%, respectively (p value 0.85). Conclusion: Generic P-Asp was observed to be efficacious and well tolerated in our patients and adequate therapeutic levels were sustained for 2 weeks.