The Food and Drug Administration (FDA) has approved Rylaze® (asparaginase erwinia chrysanthemi [recombinant]-rywn) to be administered on a Monday/Wednesday/Friday (MWF) intramuscular (IM) dosing schedule, in addition to a previously approved dosing regimen (25mg/m2 IM every 48 hours).

Rylaze is indicated for use as part of a multi-agent chemotherapeutic regimen for the treatment of acute lymphoblastic leukemia (ALL) and lymphoblastic lymphoma (LBL) in adult and pediatric patients 1 month of age and older who have developed hypersensitivity to E. coli-derived asparaginase.

The MWF dosing option was approved under the Real-Time Oncology Review pilot program based on pharmacokinetic data from the IM administration portion of a phase 2/3 study (AALL1931; Identifier: NCT04145531). The trial assessed the tolerability and efficacy of Rylaze at various dosages and routes of administration.

Findings demonstrated a positive benefit-to-risk profile for a dosing regimen of Rylaze 25mg/m2 IM on Monday morning and Wednesday morning, and 50mg/m2 on Friday afternoon. Efficacy was determined based on a demonstration of the achievement and maintenance of nadir serum asparaginase activity (NSAA) above the level of 0.1 U/mL by simulation in a virtual population. The analysis showed that more than 90% of patients achieved NSAA ≥0.1 U/mL by simulation.

The safety profile of Rylaze was consistent with that observed for patients with ALL/BLL who receive asparaginase with chemotherapy (eg, neutropenia, anemia, or thrombocytopenia). There were no new safety signals observed.

“The expansion of the Rylaze label to include a Monday/Wednesday/Friday dosing schedule provides another option to support patients in completing their planned asparaginase treatment regimen,” said Dr Luke Maese, associate professor at the University of Utah, Primary Children’s Hospital and Huntsman Cancer Institute. “The benefit of completing the full course of asparaginase has been shown in various publications, and discontinuation of asparaginase has been associated with inferior disease-free survival.”


  1. Jazz Pharmaceuticals announces US FDA approval of Monday/Wednesday/Friday intramuscular dosing schedule for Rylaze® (asparaginase erwinia chrysanthemi (recombinant)-rywn). News release. Jazz Pharmaceuticals. Accessed November 18, 2022.
  2. Maese LD, Loh ML, Choi MR, et al. Efficacy and safety of intramuscular (IM) recombinant Erwinia asparaginase in acute lymphoblastic leukemia (ALL) or lymphoblastic lymphoma (LBL): The Children’s Oncology Group (COG) AALL1931 study. Published online June 2, 2022. Journal of Clinical Oncology. doi:10.1200/JCO.2022.40.16_suppl.7001
  3. Rylaze. Package insert. Jazz Pharmaceuticals; 2022. Accessed November 18, 2022.