Last reviewed 2026-04-20 · How we verify

Asparlas (calaspargase)

Calaspargase is an L-asparaginase enzyme that catalyzes the conversion of L-asparagine into aspartic acid and ammonia, leading to the depletion of plasma asparagine and the death of leukemic cells.

Calaspargase, marketed by Pfizer Inc., is an L-asparaginase enzyme used in the treatment of acute lymphoblastic leukemia (ALL) in pediatric and young adult patients. It works by depleting plasma asparagine, which is critical for the survival of leukemic cells. Common adverse reactions include elevated transaminase, increased bilirubin, pancreatitis, and abnormal clotting studies. The drug is contraindicated in patients with a history of serious hypersensitivity, pancreatitis, thrombosis, hemorrhagic events, or severe hepatic impairment during previous L-asparaginase therapy.

At a glance

Mechanism of action

The pharmacological effect of Calaspargase is based on the depletion of plasma asparagine, which is essential for the survival of leukemic cells with low expression of asparagine synthetase.

Approved indications

• Acute Lymphoblastic Leukemia (ALL) in pediatric and adult patients
• Acute Lymphoblastic Leukemia (ALL) in pediatric patients

Common side effects

• Elevated transaminase
• Bilirubin increased
• Pancreatitis
• Abnormal clotting studies

Drug interactions

• Warfarin
• Heparin
• Other anticoagulants
• Aspirin
• Nonsteroidal anti-inflammatory drugs (NSAIDs)
• Thrombolytics
• Other antineoplastic agents
• Live vaccines
• Other vaccines

Key clinical trials

• Testing the Addition of the Anti-cancer Drug Venetoclax and/or the Anti-cancer Immunotherapy Blinatumomab to the Usual Chemotherapy Treatment for Infants With Newly Diagnosed KMT2A-rearranged or KMT2A-non-rearranged Leukemia (PHASE2)
• A Phase 2 Study to Evaluate Efficacy of Calaspargase Pegol-mknl and Decitabine Combined With Venetoclax in Pediatric, Adolescent, and Young Adult Patients With Relapsed/Refractory T-cell Acute Lymphoblastic Leukemia (T-ALL) and T- Cell Lymphoblastic Lymphoma (T-LLy) (PHASE2)
• A Study Testing the Combination of Dasatinib or Imatinib to Chemotherapy Treatment With Blinatumomab for Children, Adolescents, and Young Adults With Philadelphia Chromosome Positive (Ph+) or ABL-Class Philadelphia Chromosome-Like (Ph-Like) B-cell Acute Lymphoblastic Leukemia (B-ALL) (PHASE3)
• Studying the Effect of Levocarnitine in Protecting the Liver From Chemotherapy for Leukemia or Lymphoma (PHASE3)
• Venetoclax Basket Trial for High Risk Hematologic Malignancies (PHASE1)
• Inotuzumab Ozogamicin and Post-Induction Chemotherapy in Treating Patients With High-Risk B-ALL, Mixed Phenotype Acute Leukemia, and B-LLy (PHASE3)
• CalPeg for Newly Diagnosed Acute Lymphoblastic Leukemia (ALL) (PHASE1)
• Adding Dasatinib Or Venetoclax To Improve Responses In Children With Newly Diagnosed T-Cell Acute Lymphoblastic Leukemia (ALL) Or Lymphoma (T-LLY) Or Mixed Phenotype Acute Leukemia (MPAL) (PHASE2)

Primary sources

Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.