Dr. Paul Negulescu - The Journey to Discover CFTR Modulators for the Treatment of Cystic Fibrosis

Understanding Cystic Fibrosis

• 🧬 Cystic Fibrosis (CF) is a rare genetic disease caused by mutations in the CFTR gene, affecting multiple organs like the lungs, pancreas, and gastrointestinal system.
• 🔬 Early therapeutic efforts focused on gene therapy, but challenges in delivery led to exploring small molecule drugs to restore CFTR protein function.
• 🎯 The goal was to develop an oral medication that could reach all affected organs and address the root cause of the disease, not just symptoms.

Pioneering CFTR Modulator Discovery

• 🧪 The team utilized high-throughput screening and combinatorial chemistry to identify molecules that could act as potentiators (opening the CFTR channel) or correctors (trafficking the protein to the cell surface).
• ⚠️ Initial screens for correctors were unsuccessful, but persistent chemical exploration and computational searching eventually yielded promising compounds.
• 🔬 Optical assays and human bronchial epithelial cells from CF patients were crucial models for verifying the compounds' selective effects on CFTR function.

Developing Effective Therapies

• 💊 Ivacaftor, a potentiator, was the first approved medicine, effective for about 10% of CF patients with gating mutations.
• 🤝 First-generation correctors like lumacaftor and tezacaftor, when combined with ivacaftor, showed modest clinical benefit, improving lung function by approximately 3%.
• ✨ A triple combination therapy (elexacaftor, tezacaftor, ivacaftor, known as Trikafta) demonstrated dramatic improvements, increasing lung function by nearly 14% and normalizing sweat chloride levels.

Impact and Future Outlook

• 📈 These CFTR modulators now treat about 90% of people with CF, significantly extending life expectancy from 38 to approximately 72 years and improving quality of life.
• 🔍 Cryo-electron microscopy revealed that these drugs bind to unexpected sites on the CFTR protein, far from the F508 Dell mutation, providing new insights into their mechanism of action.
• 🌱 The work continues to address the remaining 10% of patients who do not produce CFTR protein, for whom current modulators are ineffective.
• 🚀 This new pharmacology of protein processing and function correction holds promise for treating other diseases involving protein misfolding or dysfunction.