SPIRO-2101 is an experimental treatment for cystic fibrosis (CF) that’s being developed by Spirovant Sciences, a subsidiary of Sumitovant Biopharma, whose parent company is Sumitomo Dainippon Pharma of Japan.

About SPIRO-2101

CF is caused by mutations in the CFTR gene, which contains the instructions necessary for cells to produce the cystic fibrosis transmembrane conductance regulator (CFTR) protein. The CFTR protein forms a channel in the cell membrane — the outer covering of cells — that allows chloride ions to pass in and out of cells. This process is essential to produce secretions such as tears, mucus, digestive enzymes, saliva, and sweat.

When there is a mutation in the CFTR gene, the CFTR protein cannot function properly. This causes chloride ions not to flow as they should and leads to fluids becoming thick and sticky, causing the symptoms of CF.

Researchers have identified more than 1,700 mutations in the CFTR gene that can cause CF. Many treatments that are currently available for CF only target symptoms or only work for specific subsets of mutations, such as the F508del mutation.

SPIRO-2101 is an inhaled gene therapy designed to replace the faulty version of the CFTR gene in the cells lining the inside of the lungs. The therapy uses inactive adeno-associated viruses to deliver the new gene into the cells. It could potentially treat CF patients with class 1 mutations, which cause the initial copy of the instructions — the messenger RNA — not to be produced from the genes. The treatment could also potentially help patients who do not tolerate treatment with a CFTR modulator.

SPIRO-2101 research

Currently in preclinical testing, SPIRO-2101 was granted orphan drug and rare pediatric disease designations by the U.S. Food and Drug Administration in September 2020. These designations could support and speed the therapy’s development.

The orphan drug designation is for therapies that treat diseases with less than 200,000 patients in the U.S. and comes with tax benefits, waivers of certain fees, and seven years of exclusivity once the therapy receives approval.

The rare pediatric disease designation incentivizes companies to develop therapies for rare diseases that appear in childhood by granting them special priority review vouchers if the therapy receives approval. The company can use the vouchers in the future for another therapy it is developing. Alternatively, the company can sell the voucher to another company to speed up the review process.

Spirovant is also developing two other CF gene therapies, called SPIRO-2102 and SPIRO-2110.


Last updated: Feb. 22, 2021


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