Clinical utility and implications of asparaginase antibodies in acute lymphoblastic leukemia Leukemia, 05/08/2012

Liu C et al. – Antibodies were related to clinical allergy and to low systemic exposure to asparaginase, leading to lower risk of some adverse effects of therapy.

• We studied allergic reactions and serum antibodies to E. coli asparaginase (Elspar) in 410 children treated on St. Jude Total XV protocol for acute lymphoblastic leukemia.

• Of 169 patients (41.2%) with clinical allergy, 147 (87.0%) were positive for anti-Elspar antibody.
• Of 241 patients without allergy, 89 (36.9%) had detectable antibody.
• Allergies (P=0.0002) and antibodies (P=6.6 × 10?6) were higher among patients treated on the low-risk arm than among those treated on the standard/high-risk arm.
• Among those positive for antibody, the antibody titers were higher in those who developed allergy than in those who did not (P<1 × 10?15).
• Antibody measures at week 7 of continuation therapy had a sensitivity of 87–88% and a specificity of 68–69% for predicting or confirming clinical reactions.
• The level of antibodies was inversely associated with serum asparaginase activity (P=7.0 × 10?6).
• High antibody levels were associated with a lower risk of osteonecrosis (odds ratio=0.83; 95% confidence interval, 0.78–0.89; P=0.007).