AOC 1001-CS1 is a randomized, double-blind, placebo-controlled, Phase 1/2 study to evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of single and multiple-doses of AOC 1001 Administered Intravenously to Adult Myotonic Dystrophy Type 1 (DM1) patients (MARINA).

Part A is a single dose design with 1 cohort (dose level). In Part A, the patient duration is 6 months as the treatment period is 1 day followed by a 6 month follow-up period.

Part B is a multiple-ascending dose design with 2 cohorts (dose levels). In Part B, the patient duration is 6 months as the treatment period is 3 months followed by a 3 month follow-up period.

Key Inclusion Criteria:

• Genetic diagnosis of DM1 (CTG repeat length ≥ 100)
• Clinician assessed signs of DM1
• Ability to walk independently (orthoses and ankle braces allowed) for at least 10 meters at screening

Key Exclusion Criteria:

• Diabetes that is not adequately controlled
• BMI > 35 kg/m2
• Uncontrolled hypertension
• Congenital DM1
• History of tibialis anterior (TA) biopsy within 3 months of Day 1 or planning to undergo TA biopsies during study period
• Recently treated with an investigational drug
• Treatment with anti-myotonic medication within 14 days of Day 1

Note: Other protocol defined Inclusion/Exclusion criteria may apply.