Overcoming the Limits of Inhibition: Mutant-Selective BRAF Degraders

Area of Science:

• Oncology
• Molecular Biology
• Drug Development

Background:

• Targeted therapies like ATP-competitive kinase inhibitors have advanced BRAF-V600-mutant melanoma treatment.
• These inhibitors face challenges including resistance, MAPK pathway activation, and toxicity.
• Oncoprotein-selective degraders offer a distinct approach to overcome these limitations.

Purpose of the Study:

• To develop and evaluate CFT1946, a novel, orally bioavailable, mutant BRAF-selective degrader.
• To assess CFT1946's efficacy in preclinical models, including its central nervous system penetration.
• To investigate CFT1946's potential to overcome resistance mechanisms associated with current BRAF inhibitors.

Main Methods:

• Development of CFT1946, a clinical-stage RAF family-selective degrader.
• Evaluation of CFT1946 in cellular and xenograft models of BRAF-mutant cancers.
• Assessment of CFT1946's activity within the central nervous system.
• Analysis of CFT1946's ability to circumvent resistance to standard BRAF inhibitors.

Main Results:

• CFT1946 demonstrated high potency and selectivity for RAF family proteins.
• The degrader was effective in various cellular and xenograft models.
• CFT1946 successfully penetrated the central nervous system, targeting a common site for melanoma metastasis.
• CFT1946 effectively eliminated the BRAF-V600X oncoprotein, overcoming RAF dimer- and EGFR-driven resistance.
• The compound exhibited a promising therapeutic index by sparing wild-type RAF proteins.

Conclusions:

• CFT1946 represents a promising therapeutic candidate for BRAF-V600-mutant malignancies.
• Oncoprotein-specific degradation is an emerging strategy to address limitations of current targeted therapies.
• CFT1946's ability to target the central nervous system and overcome resistance warrants further clinical investigation.