Another drug used to treat acute leukemia, L-asparaginase, is one of the most widely studied enzymes for RBC encapsulation.94 Different groups have developed various methods for preparing asparaginase-loaded RBCs, which have been evaluated for their pharmacokinetics and antitumor activities in mice,7,71 dogs,31 monkeys139 and humans.72 These studies have demonstrated the advantages of using RBC derivatives for targeting CTCs in vivo. The gene discussed is ASPG; the disease is acute leukemia.