Genomics of Resistance to Targeted Therapies

Area of Science:

• Oncology
• Hematology
• Molecular Biology

Background:

• Targeted therapies, including Bruton's tyrosine kinase (BTK) inhibitors (e.g., ibrutinib) and B-cell lymphoma 2 (BCL-2) inhibitors (e.g., venetoclax), are mainstays in chronic lymphocytic leukemia (CLL) treatment.
• Acquired resistance to these therapies is a significant clinical challenge, limiting long-term patient outcomes.
• Mutations in key signaling proteins and drug targets are increasingly recognized as drivers of this resistance.

Purpose of the Study:

• To review and synthesize the current understanding of resistance mechanisms to targeted therapies in chronic lymphocytic leukemia.
• To highlight specific mutations conferring resistance to ibrutinib and venetoclax.
• To provide insights into the molecular basis of acquired resistance in CLL.

Main Methods:

• Literature review of preclinical and clinical studies on targeted therapy resistance in CLL.
• Analysis of genetic mutations affecting drug targets such as BTK, PLCG2, and BCL2.
• Discussion of the impact of these mutations on drug binding affinity and therapeutic efficacy.

Main Results:

• The C481S mutation in BTK leads to reduced binding affinity for ibrutinib, causing reversible inhibition and resistance.
• Mutations in PLCG2 have also been identified as a mechanism of acquired resistance to ibrutinib.
• The Gly101Val mutation in BCL2 decreases venetoclax binding affinity, conferring resistance in cell lines and patient samples.

Conclusions:

• Acquired resistance to targeted therapies in CLL is frequently mediated by specific mutations in the drug targets.
• Understanding these resistance mechanisms is essential for developing next-generation inhibitors and combination therapies.
• Further research is needed to overcome resistance and improve long-term management of CLL.