The first person has been enrolled in the BUTTERFLY observational study sponsored by Stoke Therapeutics (Bedford, MA). The BUTTERFLY study is a 2-year observational study designed to measure seizure frequency and understand the nonseizure comorbidities of Dravet’s syndrome (DS), which include cognitive regression or developmental stagnation, ataxia, speech impairment, and sleep disturbances. The study is enrolling participants age 2 to 18 years who have been diagnosed with Dravet syndrome as a result of an SCN1A gene mutation. Participants will continue to receive their usual care and be followed by a clinical team for the duration of the study, which is expected to have approximately 20 sites in the US.
Stoke Therapeutics uses a proprietary technology platform, targeted augmentation of nuclear gene output (TANGO), to develop antisense oligonucleotide (ASO) therapies. The ASOs are designed to increase expression of a specific protein to treat monogenic diseases of the nervous system. Data from the study will support clinical development plans for the company’s lead therapeutic candidate, STK-001, an investigational new treatment for DS.
The target of STK-001 is the SCN1A gene that has been shown to have a spontaneous, heterozygous loss-of-function mutation in approximately 85% of people with DS. This gene encodes the voltage-gated sodium channel type 1 alpha subunit (NaV1.1), and by upregulating expression of this protein from the nonmutant copy in people with DS, Stoke hopes to provide a gene-specific, disease-modifying approach that may prevent seizures and reduce the significant nonseizure comorbidities, including developmental deficits.
“Our goal is to develop the first medicine to treat the underlying cause of Dravet syndrome,” said Barry Ticho, MD, PhD, chief medical officer of Stoke Therapeutics. “Although this study will not evaluate potential new medicines for DS, we believe it will provide important information about the range of effects of the disease on children and young adults that will be useful in planning for the clinical development of STK-001, our lead therapeutic candidate.”
“Increased awareness along with more widespread availability of genetic testing have allowed us to diagnose genetic epilepsies like DS earlier, allowing physicians to help patients and their families better manage the disease,” said Joseph Sullivan, MD, professor of Neurology at the University of California San Francisco and director of the Benioff Children’s Hospital Pediatric Epilepsy Center of Excellence. “We have made significant progress in understanding the genetic basis of many childhood epilepsies, but we still do not completely understand the full spectrum or impact of the disease. This study will give us new insights that will help us better care for our patients and improve our research and development efforts for potential new medicines with the goal of improving outcomes beyond seizure control.”