Toward Treatment of Acute Lymphoblastic Leukemia with Bacterial Cell Lysates: Production and Activity Assessment of Crisantaspase Using Cell-Free Protein Synthesis

More than 6000 people will be diagnosed with acute lymphocytic leukemia (ALL) this year in the United States alone. Gratefully, administration of bacterial asparaginases has improved survival rates to nearly 80%, but shortages in the availability of this drug can occur (with the current shortage announced in October 2019). We recently achieved a 72% improvement in E. coli cell-free protein synthesis (CFPS) production yield of L-asparaginase from Erwinia chrysanthemi (crisantaspase) by employing an aspartate-fed-batch reactor format. On-site production of therapeutic crisantaspase using CFPS may someday help eliminate asparaginase shortages in the developed world and provide on-demand access to this life-saving therapeutic in the developing world. One challenge to on-site production and administration of biologics is on-site quality control and activity assessment. In an effort toward resolving this challenge, we also recently developed a CFPS-based asparaginase activity assay and demonstrate quantification capabilities within therapeutic ranges. In the case of ALL, determining circulating activity of asparaginase in the patient during treatment facilitates much more effective therapy, and this activity assay might also be deployed to detect activity in human serum. This demonstrated potential of E. coli CFPS to 1) manufacture biologics, 2) perform quality control, and 3) monitor treatment effectiveness introduces notable synergy in applying this cell-free system to modern and humanitarian medical treatment.