Advances in Targeted Therapy: Addressing Resistance to BTK Inhibition in B-Cell Lymphoid Malignancies

Area of Science:

• Hematologic Oncology
• Molecular Mechanisms of Cancer

Background:

• B-cell lymphoid malignancies are diverse hematologic cancers.
• Bruton's tyrosine kinase (BTK) inhibitors are FDA-approved treatments for several subtypes.
• Covalent BTK inhibitors like Ibrutinib target the C481 residue, but resistance can emerge.

Purpose of the Study:

• To review molecular and genetic mechanisms of resistance to covalent and non-covalent BTK inhibitors.
• To discuss emerging therapeutic strategies, including BTK degraders, for overcoming resistance.

Main Methods:

• Review of existing literature on BTK inhibitor resistance.
• Analysis of molecular pathways and genetic mutations conferring resistance.
• Discussion of novel therapeutic approaches like proteolysis-targeting chimeras (PROTACs).

Main Results:

• Resistance to covalent BTK inhibitors can arise from mutations at the BTK binding site (C481S) or other sites, and mutations in PLCγ2.
• Non-covalent BTK inhibitors, such as Pirtobrutinib, are effective against wild-type and C481S mutated BTK.
• BTK degraders represent a promising new class of therapeutics for overcoming resistance.

Conclusions:

• Understanding resistance mechanisms is crucial for developing effective BTK-targeted therapies.
• Emerging strategies, including non-covalent inhibitors and BTK degraders, offer new avenues for treating resistant B-cell malignancies.
• Continued research into resistance and novel therapeutics advances the pursuit of a cure for these cancers.