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Antifolate analogs: mechanism of action, analytical methodology, and clinical efficacy
1Department of Clinical Chemistry, Memorial Sloan-Kettering Cancer Center, New York, New York 10021.
Abstract:
Antifolates have demonstrated effective antineoplastic activity in the treatment of disorders of cell proliferation, e.g., acute lymphocytic leukemia, breast cancer, and mycosis fungoides. The enzymatic pathways involved in DNA biosynthesis, specifically dihydrofolate reductase and thymidylate synthetase, are the biochemical targets of antifolates. Methotrexate (MTX) and its analogs, 10-ethyl-10-deazaaminopterin (edatrexate), and trimetrexate (TMT) are paradigms for cytotoxicity at the biochemical level. Understanding the cellular pharmacology of MTX and other antifolates has provided a strong rationale for the use of high-dose MTX with leucovorin (LV) rescue. The combination of MTX and LV prevents severe toxicity without diminishing the antitumor activity of the drugs. The efficacy of antifolate drugs is related to the extent of intracellular polyglutamation in normal and cancer cells. Since toxicity in patients is difficult to predict, monitoring drug concentrations is critical. Antifolates, specifically MTX and edatrexate, are among a growing class of chemotherapeutic agents that require assiduous and rapid monitoring to help prevent severe systemic toxicity. Chemical and physical properties, mechanism of chemotherapeutic activity, and analytical methodology for measurement of serum concentrations of antifolates will be discussed.
Insights
Antifolates are effective cancer drugs targeting DNA biosynthesis. Monitoring their serum concentrations, like Methotrexate (MTX) with leucovorin (LV) rescue, is crucial for preventing toxicity while maintaining antitumor activity.
Area of Science:
- Biochemistry
- Pharmacology
- Oncology
Background:
- Antifolates exhibit significant antineoplastic activity against various cancers by inhibiting DNA biosynthesis enzymes.
- Key targets include dihydrofolate reductase and thymidylate synthetase, crucial for cell proliferation.
- Methotrexate (MTX) and its analogs (edatrexate, trimetrexate) are established cytotoxic agents.
Purpose of the Study:
- To discuss the cellular pharmacology of antifolates, particularly Methotrexate (MTX).
- To explain the rationale behind high-dose MTX with leucovorin (LV) rescue.
- To highlight the importance of monitoring antifolate serum concentrations for toxicity management.
Main Methods:
- Review of antifolate mechanisms of action and cellular pharmacology.
- Discussion of analytical methodologies for measuring serum antifolate concentrations.
- Exploration of factors influencing drug efficacy, such as polyglutamation.
Main Results:
- High-dose MTX combined with leucovorin (LV) rescue mitigates toxicity without compromising antitumor effects.
- Intracellular polyglutamation levels correlate with the efficacy of antifolate drugs.
- Predicting patient toxicity is challenging, underscoring the need for drug monitoring.
Conclusions:
- Antifolates like MTX and edatrexate require diligent and rapid serum concentration monitoring to prevent severe systemic toxicity.
- Understanding antifolate pharmacology supports therapeutic strategies like MTX-LV rescue.
- Analytical methods for antifolate measurement are essential for safe and effective cancer chemotherapy.