Saol Therapeutics resubmitted its application for SL1009, a treatment for pyruvate dehydrogenase complex deficiency, to the Food and Drug Administration on July 9. The move comes ten months after the agency rejected the company's initial application, which Saol previously said would take several years and significant financial resources to address.
The resubmission follows Type A and Type C meetings with the FDA. During a December meeting, Saol requested to directly resubmit its application but was advised by the agency to first participate in a Type C meeting so both parties could agree on submission content. "We’re hoping that that leads to a faster review," CEO Dave Penake told BioSpace. The company’s new filing includes additional survival analyses as recommended by the FDA, as well as information from emergency Investigational New Drug programs. Penake said this should allow for a six-month review period, "if they go by the book," though he noted that recent reviews have not always adhered strictly to standard timeframes.
SL1009 is also known as DCA and is intended for an ultra-rare mitochondrial disease without any approved treatments. The candidate was among several rare disease therapies rejected by the FDA in late 2025; other companies affected included Capricor Therapeutics, Biohaven, and Replimune. Both Capricor’s Duchenne muscular dystrophy therapy deramiocel and Replimune’s advanced melanoma drug RP1 have since been resubmitted and received new target action dates this summer.
If accepted, SL1009 would join other therapies benefitting from what some view as increased flexibility at the FDA following leadership changes earlier this year. Companies such as uniQure and REGENXBIO have also announced plans or actions to refile applications after previous regulatory setbacks were reconsidered under current agency leadership.
Penake said Saol has addressed concerns raised in last year’s complete response letter with new data including 36 natural history–matched pairs—up from about 28 previously—and an extra 18 months of results showing a 91% reduction in risk of death with SL1009. At the time of last year's rejection, the United Mitochondrial Disease Foundation warned that delaying access could lead to "irreversible damage—or even death." Regarding Saol's renewed efforts, Penake said, “We’re just excited to be working with the agency and helping these kids.”
