The toxicity of cytarabine

Area of Science:

• Hematology
• Oncology
• Pharmacology

Background:

• Standard induction regimens for acute non-lymphocytic leukemia (ANLL), including cytarabine (ARA-C) and anthracyclines, are associated with substantial myelotoxicity, leading to mortality in a significant percentage of patients.
• Older patients (>65 years) exhibit reduced complete remission rates (<35%) and increased susceptibility to myelotoxicity from standard-dose ARA-C.
• Gastrointestinal toxicities, such as mucositis and diarrhea, are common with standard-dose ARA-C, alongside idiosyncratic reactions like fever and hepatic enzyme elevation.

Purpose of the Study:

• To evaluate the toxicity profiles of standard and high-dose cytarabine (ARA-C) regimens in acute non-lymphocytic leukemia (ANLL) treatment.
• To assess the impact of age on ARA-C toxicity and treatment outcomes.
• To explore the safety and efficacy of different administration methods (intermittent vs. continuous infusion) and doses of ARA-C.

Main Methods:

• Review of existing literature on cytarabine (ARA-C) toxicity in ANLL treatment.
• Analysis of adverse effects associated with standard induction regimens (ARA-C 100 mg/m2) and high-dose intermittent regimens (3 g/m2).
• Comparison of toxicities based on patient age and administration methods (continuous vs. intermittent infusion).

Main Results:

• Standard induction regimens cause significant myelotoxicity and gastrointestinal toxicity, with mortality in at least 25% of non-selected patients.
• High-dose intermittent ARA-C is highly myelosuppressive and dose-limiting due to gastrointestinal toxicity and severe neurotoxicity (5-15% of courses), particularly in patients over 55-60 years.
• Low-dose cytarabine is generally well-tolerated, with myelosuppression as the primary toxicity, though occasional gastrointestinal and neurological adverse events are reported.

Conclusions:

• The toxicity of standard induction regimens for ANLL is acceptable for patients younger than 60-65 years without comorbidities.
• High-dose cytarabine therapy is limited by severe age-related toxicities, especially in older patients.
• Low-dose cytarabine is a tolerable option for most ANLL patients, but its overall therapeutic efficacy requires further definition and comparison with standard therapies.