ARV-1801 (sodium fusidate) is an experimental therapy being developed by Arrevus to treat pulmonary exacerbations in people with cystic fibrosis (CF). Although investigational in the U.S., the treatment is part of standard care in the U.K. and Australia.

The U.S. Food and Drug Administration granted ARV-1801 priority review and qualified infectious disease product designations in January 2020.

How does ARV-1801 work?

CF is a genetic disease caused by mutations in a gene called CFTR, which encodes for a protein channel that controls the movement of ions in and out of cells. When the ion balance in cells is not maintained correctly, the tissues and organs become coated in thick, sticky mucus, which interferes with their function.

In the lungs, this mucus is especially problematic; in addition to inhibiting the movement of the lungs and the movement of oxygen into the body, it also makes the lungs much more susceptible to infections.

ARV-1801 contains sodium fusidate, a potent antibiotic against the bacterium Staphylococcus aureus, which is responsible for about 70% of lung infections in CF patients. The antibiotic is also effective against one of the drug-resistant strains of Staphylococcus aureus (MRSA).

Sodium fusidate acts against bacteria by inhibiting an important step in protein synthesis. Because bacteria and people have different protein synthesis pathways, only the bacteria are affected by the therapy.

The compound also has anti-inflammatory and mucus-clearing properties.

ARV-1801 in clinical trials

A study published in 1982 in the journal Acta Paedriatica reviewed CF cases of Staphylococcus aureus over 15 years. During this period of time, 191 CF patients were treated with sodium fusidate in combination with oxacillin or dicloxacillin (antibiotics similar in structure to penicillin) given for 14 days. For patients who were allergic to the penicillin family of antibiotics, sodium fusidate was instead given in combination with rifampin.

The researchers found that a single course of treatment was sufficient to eradicate the infection in 74% of the cases. Repeated or extended treatment was successful in most of the remaining cases, with the infection lasting six months or more in 9% of the cases. Most patients were treated twice per year (on average) but a reduction in efficacy was not seen with repeated use of the treatment.

Arrevus is planning to conduct a Phase 2 clinical trial to study ARV-1801 in treating pulmonary exacerbations in CF patients.


Last updated: Feb. 20, 2020


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