Resistance to Bruton Tyrosine Kinase Inhibitors

Area of Science:

• Oncology
• Pharmacology
• Hematology

Background:

• Bruton tyrosine kinase (BTK) inhibitors have transformed chronic lymphocytic leukemia (CLL) treatment.
• Therapeutic resistance to BTK inhibitors is a growing clinical challenge.
• Understanding resistance mechanisms is crucial for improving patient outcomes.

Purpose of the Study:

• To review common and emerging resistance mechanisms to BTK inhibitors in CLL.
• To discuss the impact of BTK mutations on covalent and noncovalent inhibitor efficacy.
• To highlight the proportion of resistance cases not explained by BTK mutations.

Main Methods:

• Literature review of studies on BTK inhibitor resistance in CLL.
• Analysis of reported BTK mutations (e.g., C481S, C481Y/R/F, T474I, L528W).
• Discussion of resistance mechanisms beyond BTK mutations.

Main Results:

• C481 residue mutations are the most frequent cause of resistance to covalent BTK inhibitors.
• Noncovalent inhibitors show activity against C481 mutations but can face alternative BTK mutations.
• Approximately one-third of resistance cases are not linked to BTK mutations and require further investigation.

Conclusions:

• BTK inhibitor resistance in CLL is multifactorial, involving target mutations and other poorly understood mechanisms.
• The development of resistance necessitates ongoing research into novel therapeutic approaches.
• Further studies are needed to elucidate non-BTK mutation-related resistance pathways.