The Modulator Era: Where CF Treatment Stands Now

For most of the history of cystic fibrosis, treatment meant managing symptoms. The daily airway-clearance vest, the enzyme pills with every meal, the ongoing effort to control lung infections. It was demanding, and it was not a cure. CFTR modulators changed that approach. Rather than treating symptoms, they target the defective protein that causes the disease in the first place.

CFTR is a protein that regulates salt and water movement across cell membranes. When it works, it keeps mucus in the lungs and digestive tract thin and mobile. In people with CF, mutations in the CFTR gene mean the protein is either absent or malfunctioning, so mucus becomes thick and sticky. That mucus traps bacteria and drives progressive lung damage. Modulators help the defective protein fold and function closer to normal.

Trikafta (elexacaftor/tezacaftor/ivacaftor) has been the primary example. For patients whose mutations respond to it, the data show meaningful gains in lung function and reductions in pulmonary exacerbations and hospitalizations. The FDA has expanded its approval to eligible patients as young as age 2, which means children diagnosed early can begin protecting lung function before significant damage occurs.

A next-generation once-daily modulator, Alyftrek (vanzacaftor/tezacaftor/deutivacaftor), followed. The FDA approved it in December 2024 for patients ages 6 and older who carry at least one responsive mutation, with a once-daily regimen intended to simplify dosing.

The point relevant to fundraising is that modulators do not work for everyone. They are designed for specific classes of CFTR mutations. Roughly one in ten people with CF carries a mutation that current modulators cannot address, including many nonsense and rare mutations that produce little or no protein for the drugs to act on. For those patients, none of the modulator gains apply.

That remaining group, often called the "final 10%," is where the next stage of CF research is focused. Our next post covers it.