Chemotherapy resistance in Acute Leukemia.

Area of Science:

• Oncology
• Pharmacology

Background:

• Drug resistance markers predict treatment response in acute myeloid leukemia (AML).
• P-glycoprotein (Pgp) and multidrug resistance-associated protein 1 (MRP1) are key drug efflux pumps implicated in resistance.
• Other markers like LRP, bcl-2, and BCRP have unclear clinical relevance and standardization issues.

Purpose of the Study:

• To review the role of drug resistance markers in AML.
• To evaluate strategies for overcoming drug efflux-mediated resistance.
• To explore the clinical utility of efflux pump inhibitors.

Main Methods:

• Review of preclinical studies on efflux pump reversers.
• Analysis of clinical trials involving drug efflux blockers.
• Discussion of pharmacokinetic interactions and toxicities.

Main Results:

• Preclinical studies show efflux reversers can restore drug sensitivity.
• Clinical studies with early reversers were limited by potency and specificity.
• Later studies faced challenges with pharmacokinetic interactions and toxicity.
• One study showed a survival advantage with cyclosporine without increased toxicity.

Conclusions:

• Overcoming Pgp overexpression requires complex strategies beyond simple efflux blockers.
• Additional resistance mechanisms necessitate multifaceted therapeutic approaches.
• Preventing or delaying resistance in chemosensitive patients is a viable strategy.