Saol Therapeutics announced that the U.S. Food and Drug Administration has issued a Complete Response Letter regarding its New Drug Application for SL1009, an investigational sodium dichloroacetate oral solution designed to treat Pyruvate Dehydrogenase Complex Deficiency, a rare and life-threatening pediatric mitochondrial disease. The FDA's action requires the company to address specific deficiencies before potential approval, though manufacturing issues were not cited among the concerns.
Regulatory Setback for Ultra-Rare Disease Treatment
The Complete Response Letter represents a significant regulatory hurdle for SL1009, which has received Orphan Drug, Priority Review, and Rare Pediatric Disease Designations from the FDA. According to Saol, addressing the FDA's observations would require several years and significant financial resources, prompting the company to seek alternative pathways that avoid additional clinical trials.
"Families living with PDCD face an urgent and life-threatening unmet need," said Dave Penake, CEO of Saol Therapeutics. "We are encouraged by recent FDA actions and commentary that recognize the importance of regulatory flexibility and speed for treating rare diseases. Traditional clinical trials often take many years; time that children with PDCD simply do not have."
Disease Burden and Unmet Medical Need
PDCD affects fewer than 1,000 individuals in the United States, with an incidence estimated at 1 in 40,000 live births, representing approximately 90 newborns annually. The rare genetic disorder causes chronic energy deficits leading to lactic acidosis, profound developmental problems, and early childhood death. Most children diagnosed with PDCD, particularly those with early-onset forms, face overwhelming health challenges, and many do not survive beyond early childhood.
Currently, no FDA-approved treatments exist for PDCD, highlighting the critical unmet medical need in this patient population.
Clinical Evidence and Development Program
Saol's confidence in SL1009 stems from four years of clinical data gathered through two phase III studies, including a double-blind placebo-controlled trial that continues in open-label extension, and a survival analysis compared to a natural history cohort. The company emphasizes SL1009's established safety profile as supporting evidence for its potential therapeutic value.
SL1009 is designed to be used with a proprietary dose-determining genetic test, for which Saol, in collaboration with Medosome Biotec, has filed a Humanitarian Device Exemption application. This companion diagnostic would serve as a required component for patient treatment.
Continued Patient Access
Despite the regulatory setback, Saol has committed to maintaining uninterrupted patient access to SL1009 through multiple channels. The ongoing open-label extension of the clinical trial (NCT02616484) and the Expanded Access Program (NCT06931262) will continue to provide treatment options. The expanded access program also includes emergency support for neonates with life-threatening lactic acidosis due to inborn errors of metabolism.
The company remains dedicated to working with the FDA toward a resolution and has indicated that further updates will be provided as discussions with the agency progress. Saol's approach reflects the broader challenges facing rare disease drug development, where traditional clinical trial timelines may not align with the urgent needs of patients facing life-threatening conditions.
