Berlin, Germany – A new experimental therapy using a miniaturized antibody, known as a nanobody, may help restore the function of the defective CFTR protein in people with cystic fibrosis (CF) caused by the F508del mutation.
Early (preclinical) findings suggest that this nanobody works especially well when combined with Trikafta—a widely used CF therapy made up of ivacaftor, tezacaftor, and elexacaftor. Together, the two treatments restored CFTR activity to near-normal levels, a significant improvement over existing approaches.
According to Marcus Mall, director of pediatric respiratory medicine at Charité – Universitätsmedizin Berlin:
“Because the nanobodies bind directly at the site of the F508del mutation, they allow for much more precise correction of the CFTR defect. Combined with Trikafta, this approach may significantly improve CFTR function—potentially even normalizing it.”
The study, published in Nature Chemical Biology, highlights a promising new direction in CF treatment.
Why Smaller Antibodies Matter
Antibodies are highly specific proteins used by the immune system—and increasingly in medicine—to target disease-related molecules. However, traditional antibodies are very large, which limits their ability to enter cells. As a result, most antibody-based therapies can only target molecules outside cells or on their surface.
This is a major limitation for CF, where the problem lies inside cells.
CF is caused by mutations in the gene that produces the CFTR protein. Normally, CFTR is built inside cells and then transported to the cell membrane, where it helps regulate mucus. The F508del mutation—the most common cause of CF—causes the protein to misfold and break down before reaching the membrane.
A New Strategy: Cell-Penetrating Nanobodies
To overcome this challenge, researchers developed a nanobody-based therapy designed to work inside cells:
- Smaller size: Nanobodies are stripped-down versions of antibodies, making them compact enough to function in tighter biological spaces
- Cell entry capability: Scientists added a molecular “key” that allows the nanobody to cross cell membranes
This engineered nanobody can bind directly to the faulty CFTR protein and help stabilize it, preventing its premature breakdown.
In laboratory studies—including lung cells from CF patients—the nanobody improved CFTR function by helping the protein fold properly and reach its intended location.
Stronger Results in Combination with Trikafta
Researchers also tested the nanobody alongside Trikafta, which already helps stabilize CFTR proteins.
- Trikafta alone: Restored CFTR function to just over 50% of normal
- Combination therapy: Increased function to nearly 90% of normal
This suggests a synergistic effect, where the two treatments enhance each other’s impact.
As the researchers noted, current CF therapies often provide only partial correction. This new approach could help overcome that limitation.
A First Step Toward New Therapies
This study is also notable because it represents the first example of a cell-penetrating antibody with therapeutic potential. That opens the door not only for CF treatment, but also for applying similar strategies to other diseases involving intracellular defects.
Vertex Pharmaceuticals, which markets Trikafta, was not involved in the research.
Bottom Line
This nanobody-based therapy is still in early stages, but it introduces a powerful idea:
combining targeted, cell-penetrating antibodies with existing drugs to achieve near-normal protein function.
If confirmed in clinical trials, this approach could mark a major advance in the treatment of cystic fibrosis—and potentially many other genetic diseases.
Footnote
Trikafta is sold by Vertex Pharmaceuticals. The company wasn’t directly involved in the study.
Contact
Prof. Dr. med. Marcus A. Mall
Email: [email protected]
Phone: +49 30 450 566 131