Saol Resubmits FDA Application for SL1009 in Rare Pediatric Mitochondrial Disease After Additional Survival Analyses

Saol Therapeutics has resubmitted its New Drug Application  to the U.S. Food and Drug Administration (FDA) for SL1009 (sodium dichloroacetate, DCA) as a treatment for pyruvate dehydrogenase complex deficiency (PDCD), a rare, life-threatening mitochondrial disease with no FDA-approved therapies.

The resubmission follows Type A and Type C meetings with the FDA in December 2025 and March 2026, during which the agency recommended expanded survival analyses to strengthen the application. According to the company, the FDA allowed the NDA to proceed without requiring a new clinical trial, relying instead on strengthened analyses of existing clinical evidence.

Addressing the Complete Response Letter

SL1009 previously received a Complete Response Letter (CRL) from the FDA in August 2025. While the agency raised no concerns regarding the therapy’s safety or manufacturing, it requested additional evidence supporting its clinical benefit. In response, Saol conducted further analyses of existing data, incorporating functional outcomes, survival data, mechanistic evidence, and long-term safety findings from completed studies.

Disease Background

PDCD is a rare inherited mitochondrial disorder caused by impaired activity of the pyruvate dehydrogenase complex, an enzyme essential for cellular energy production. The disease typically presents during infancy or early childhood and can lead to persistent lactic acidosis, severe neurological impairment, developmental delay, and early death. Management is currently limited to supportive care, underscoring the significant unmet medical need for disease-specific therapies.

Investigational Therapy and Companion Diagnostic

If approved, SL1009 would be prescribed alongside a proprietary genetic test that determines individualized dosing based on a patient’s genetic profile. Saol, in collaboration with Medosome Biotec, has also submitted a Humanitarian Device Exemption (HDE) application for this companion diagnostic, which would be required for patients receiving SL1009.

Clinical Development Program

The SL1009 development program includes two Phase III clinical trials and long-term open-label extension studies. Although the company did not disclose new efficacy results as part of the resubmission announcement, according to Saol, the accumulated evidence supports a well-characterized safety profile and the potential for meaningful clinical benefit in patients with PDCD. The company also reported that no new safety concerns have emerged.

Chief Executive Officer Dave Penake said recent interactions with the FDA provided clear regulatory direction, enabling the company to strengthen the application using existing clinical data rather than conducting an additional trial. He also acknowledged the contributions of patients, families, clinicians, researchers, and advocacy groups in raising awareness of PDCD and supporting the development program.

Regulatory Designations and Next Steps

If the FDA accepts the resubmitted NDA for review, the agency will assign a new Prescription Drug User Fee Act (PDUFA) target date. SL1009 has received Priority Review, Orphan Drug Designation, and Rare Pediatric Disease Designation. If approved, the therapy is also expected to qualify for a Rare Pediatric Disease Priority Review Voucher (PRV), providing an additional regulatory incentive while potentially becoming the first FDA-approved treatment for patients with PDCD.

What This Means for Patients

For families affected by PDCD, the NDA resubmission marks another step toward a potential first approved therapy for a rare disease with high mortality and limited treatment options. The FDA’s decision to consider expanded analyses from existing clinical studies, rather than requiring a new trial, could shorten the regulatory review timeline. If approved, SL1009, together with its companion genetic test, could provide a precision medicine approach that individualizes treatment while helping address a critical unmet need in pediatric mitochondrial disease.

Reference

Saol Therapeutics Resubmits the New Drug Application for SL1009 (DCA) for the Treatment of Pyruvate Dehydrogenase Complex Deficiency (PDCD), an Ultra-Rare Disease – Saolrx