Cystic fibrosis allowed most affected individuals barely to reach their thirtieth year of life. On April 1, 2026, the US Food and Drug Administration approved an expansion of the approved indication for Alyftrek, a once-daily CFTR modulator from Vertex Pharmaceuticals. For the first time, 95 percent of all CF patients in the US can receive therapy that directly corrects the genetic defect at the protein level rather than merely alleviating symptoms.
1989: The gene behind the disease
Cystic fibrosis, clinically cystic fibrosis (CF), is caused by mutations in the CFTR gene, which sits on chromosome 7 and controls production of a chloride channel protein. In 1989, geneticists Lap-Chee Tsui and Francis Collins identified the gene and showed that roughly 70 percent of all CF mutations stem from the absence of a single amino acid, known as F508del. In the decades that followed, over 2,000 additional variants of the CFTR gene were mapped.
When the CFTR channel is absent or faulty, the body produces thick mucus in the lungs, digestive tract, and other organs, triggering airway inflammation and blocking the pancreas. In the US, roughly 33,989 people live with the diagnosis according to the CF patient registry of the Cystic Fibrosis Foundation; globally, studies estimate about 162,400 affected individuals in 94 countries, with significant underreporting in regions without systematic newborn screening. Until the early 2010s, CF remained medically manageable but not treatable.
2012 to 2019: From 4 to 90 percent
The first breakthrough came in 2012 with Kalydeco (ivacaftor), the first medicine worldwide that not combats symptoms but directly targets the faulty CFTR protein. Kalydeco keeps the chloride channel open longer, which only works if the channel is fundamentally present but opens too rarely. This applies to gating mutations, affecting roughly 4 to 5 percent of all CF patients.
The next generation combined correctors with a potentiator: Orkambi (lumacaftor/ivacaftor, 2015) and Symdeko (tezacaftor/ivacaftor, 2018) achieved modest improvements for patients with two copies of F508del. The true turning point came in 2019 with Trikafta (elexacaftor/tezacaftor/ivacaftor): by using two correctors plus a potentiator, roughly 90 percent of all CF patients became treatable for the first time, as the combination works even if only one of the two CFTR copies carries F508del. The median life expectancy of CF patients in the US rose according to Cystic Fibrosis Foundation data from roughly 30 years before the modulator era to roughly 65 years for those today with access to newer therapies.
December 2024 and April 2026: 95 percent and once daily
Alyftrek (vanzacaftor/tezacaftor/deutivacaftor) received its first FDA approval on December 20, 2024. Like Trikafta, it contains two correctors that bring the misfolded CFTR protein into its correct shape and direct it to the cell surface. The potentiator is exchanged: instead of ivacaftor, requiring twice-daily doses, Alyftrek contains deutivacaftor, a chemically modified variant with longer half-life in the body. This makes once-daily dosing possible.
In two Phase 3 studies with 971 patients at 212 sites in 23 countries, Alyftrek showed non-inferiority to Trikafta on lung function (ppFEV1). On the sweat chloride value, a surrogate marker for CFTR activity, Alyftrek performed better according to Vertex: 86 percent of Alyftrek patients achieved normal values below 60 mmol/l after 24 weeks, compared with 77 percent on Trikafta.
The FDA expansion of April 1, 2026, goes beyond the original approval. Instead of only patients with known standard mutations, now all CF patients whose CFTR gene still produces any protein can be treated, regardless of the exact variant. Vertex submitted clinical and in vitro data for 564 CFTR variants. The expansion brings roughly 800 additional US patients into initial therapy who previously had no causative treatment option.
In comparison: When diseases stop being fatal
The CF development of the past twelve years stands alongside other cases where targeted therapies fundamentally rewrote a disease's prognosis. In spinal muscular atrophy (SMA), 91 percent of infants treated with gene therapy Zolgensma, approved 2019, survived 14 months without permanent ventilation, compared with roughly 25 percent without therapy. Hepatitis C was chronically incurable until 2014; with direct-acting antivirals, it is now curable in over 95 percent of cases. HIV-infected individuals on modern triple therapy have a life expectancy approaching the general population.
What distinguishes CF from these examples: transformation came not through a single breakthrough but through six approvals in twelve years, each expanding the patient group and improving efficacy. This is a template for other rare genetic diseases where the mutation landscape is too diverse to cover with a single medicine.
Where 95 percent ends: Price, access, and the remaining 5 percent
FDA approval does not mean 95 percent of all CF patients worldwide can immediately be treated. Alyftrek is currently approved only in the US; the European approval process at the EMA is ongoing. Vertex has not published a list price for Alyftrek; Trikafta costs roughly $300,000 per year in the US. In countries without bargaining power or state health insurance, even Trikafta is factually inaccessible to most patients despite being approved since 2019. Patient organizations like the Cystic Fibrosis Foundation have been pushing for access solutions in low-income countries for years.
The remaining 5 percent of CF patients carry Class I mutations, so-called nonsense mutations, where no CFTR protein is produced. CFTR modulators do not work without protein as a target. For this group, researchers pursue different approaches: RNA-based therapies allowing stop codons to be read through and gene therapies introducing a functional CFTR copy into cells. Clinical trials are underway. Approval is yet to come.