Fragile X treatment KER-0193 gets FDA orphan, rare disease tags
Kaerus Bioscience's small molecule targets BK channels
KER-0193, an oral therapy being developed as a fragile X syndrome treatment, has been awarded orphan drug and rare pediatric disease designations by the U.S. Food and Drug Administration (FDA).
These designations — which follow news of positive Phase 1 trial data from a test in healthy volunteers and plans for a Phase 2 trial in fragile X patients — are “an important step towards our objective of delivering an effective treatment for people with Fragile X syndrome,” Robert Ring, PhD, CEO of developer Kaerus Bioscience, said in a company press release.
The FDA gives orphan drug designation to experimental therapies designed to treat rare diseases. Rare pediatric disease designation is reserved for investigational treatments for rare diseases that predominantly affect children. Both statuses aim to give extra incentives for companies that are investing in developing treatments for rare diseases.
Should KER-0193 be approved in the U.S., Kaerus would get seven years of market exclusivity thanks to the orphan drug status, and the rare pediatric disease designation would make it eligible to receive a voucher that could be used to speed the FDA’s review of a future experimental treatment. Kaerus could use the voucher itself or sell it; these vouchers often go for millions of dollars.
“Not only do these two FDA designations affirm the therapeutic potential of KER-0193 in Fragile X syndrome, they also provide Kaerus with access to significant regulatory and financial incentives as we look to progress the drug through clinical trials and ultimately take it to market,” Ring said.
Fragile X treatment targets BK channels
Paul Sekhri, chairman of Kaerus, said the designations “are more excellent news for Kaerus” and “put the company in a superb position as we look to move into Phase 2 trials.”
Fragile X syndrome is caused by mutations in the gene that provides instructions to make FMRP, a protein that’s important for maintaining the connections between nerve cells and that normally interacts with proteins called calcium-activated potassium (BK) channels.
BK channels, found on the surface of nerve cells, can open or close to allow charged particles called ions to flow in or out of the cell. When the channels are open, they trigger a flow of ions that leads the nerve cell to be less likely to send an electrical signal.
When the interaction between FMRP and BK channels is impaired in fragile X, the BK channels don’t stay open as long as they should. As a result, nerve cells are prone to send too many electrical signals, which is thought to contribute to fragile X symptoms like sensory overload and hyperactive behavior.
KER-0193 is an orally available small molecule designed to help BK channels stay open longer, normalizing the electrical activity of nerve cells.
Kaerus recently announced results from a Phase 1 clinical trial (EUCT 2024-511468-94-00) that tested KER-0193 in healthy volunteers and found it to be generally well tolerated.
Data from a preplanned study within the Phase 1 trial indicated KER-0193 affects brain activity as designed, resulting in less excitability in brain regions known to be affected in fragile X patients.
“These results replicated observations … in preclinical animal studies, demonstrating proof of mechanism,” the company said.
Kaerus is finishing preparations to launch a proof-of-concept Phase 2 study testing KER-0193 in people with fragile X syndrome. The company is also considering the therapy’s potential in other neurological diseases in which nerve cells are overactive due to reduced BK channel activity, including some types of epilepsy.
“We are actively exploring opportunities to expand the therapeutic potential of our BK modulator platform to these other indications, where patient populations struggle with significant unmet treatment needs,” Ring said.
About the Author
