Last reviewed · How we verify
Elspar (ASPARAGINASE)
RYLAZE kills leukemic cells by depleting plasma asparagine, which they need for survival.
ASPARAGINASE (Elspar), marketed by Merck & Co., is a key treatment for Acute Lymphoblastic Leukemia (ALL) that depletes plasma asparagine to kill leukemic cells. The drug's key strength lies in its unique mechanism of action, which differentiates it from other same-class competitors such as altretamine, hydroxycarbamide, pentostatin, masoprocol, and mitotane. A primary risk is the key composition patent expiry in 2028, which could lead to increased competition from generics.
At a glance
| Generic name | ASPARAGINASE |
|---|---|
| Sponsor | Merck & Co. |
| Drug class | Asparagine-specific Enzyme [EPC] |
| Target | L-asparagine |
| Modality | Enzyme |
| Therapeutic area | Oncology |
| Phase | FDA-approved |
| First approval | 1994 |
| Annual revenue | 600 |
Mechanism of action
RYLAZE works by converting L-asparagine into aspartic acid and ammonia. This depletion of asparagine in the blood starves leukemic cells, which rely on external sources of asparagine because they can't produce enough themselves.
Approved indications
- Acute Lymphoblastic Leukemia (ALL)
- Lymphoblastic Lymphoma (LBL)
Common side effects
- abnormal liver test
- abnormal liver test
- musculoskeletal pain
- musculoskeletal pain
- nausea
- nausea
- fatigue
- fatigue
- headache
- headache
- infection
- infection
Key clinical trials
- An Open-Label Study of JZP-458 (RC-P) in Patients With Acute Lymphoblastic Leukemia (ALL)/Lymphoblastic Lymphoma (LBL) (PHASE2,PHASE3)
- 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 Study to Investigate Blinatumomab in Combination With Chemotherapy in Patients With Newly Diagnosed B-Lymphoblastic Leukemia (PHASE3)
- A Study to Learn More About the Study Medicine Called Inotuzumab Ozogamicin (InO) in Children (1 to <18 Years) With First Relapse ALL (PHASE2)
- Capizzi Escalating Methotrexate Versus High Dose Methotrexate in Children With Newly Diagnosed T-cell Lymphoblastic Lymphoma (T-LBL) (PHASE3)
- LBL-2016 for Children or Adolescents in China (PHASE3)
- Asparaginase Erwinia Chrysanthemi With Chemotherapy for the Treatment of High-Risk Adults With Newly Diagnosed Acute Lymphoblastic Leukemia or Lymphoblastic Lymphoma (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)
Primary sources
Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.
| Source | Used for |
|---|---|
| FDA label | Mechanism, indications, dosing, boxed warnings, drug interactions |
| ClinicalTrials.gov | Trial enrolment, design, endpoints, results |
| SEC EDGAR | Revenue + earnings |
Competitive intelligence
For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:
- Elspar CI brief — competitive landscape report
- Elspar updates RSS · CI watch RSS
- Merck & Co. portfolio CI