A Phase 1b Study of Adenylosuccinic Acid (ASA-001) for Adenylosuccinate Synthase 1 (ADSS1) Deficient Myopathy.

Open to people ages 18 years and up

• Male and females, age 18 years and above and weighing between 60 and 85 kg
• Patient(s) diagnosed with ADSS1 deficient myopathy with homozygous or compound heterozygous mutations in the ADSS1 gene.
• Able to understand and comply with all the study requirements
• Is willing and legally able to provide written informed consent.
• Willing to use highly effective contraception

• Any medical condition that could, in the Investigator's opinion, adversely affect the safety of the patient, make it unlikely that the course of treatment would be completed, or impair the assessment of study results.
• Any patient who, in the Investigator's opinion, seems unable/unwilling to comply with the study procedures.
• Women who are pregnant or breastfeeding, or planning to become pregnant
• As judged by the investigator, clinical features are present at the time of screening / baseline assessments indicating that safe travel and completion of the study and its assessments are unlikely
• Other severe systemic illness or disease
• Participation in another treatment clinical study within thirty (30) days or 5 half-lives of the investigational product, whichever is longer, prior to signing and dating of Informed Consent Form for this study.
• Known hypersensitivity to any of the components/excipients in ASA-001
• Serologic evidence of hepatitis B, C, or HIV
• Ongoing/active infection (including current COVID-19 infection)
• Presence of clinically significant liver or renal abnormalities
• Clinical chemistry and hematology outside the limits acceptable for this patient population
• History of anaphylaxis or severe allergic reaction to drug therapy or foods.
• Concomitant medications to manage chronic condition(s) must not interfere with the mechanism of action for ASA-001 in the opinion of the Investigator and dose(s) must not alter for at least 4 weeks before screening through to dosing (Day 1).