Global Open-Label Extension Study of Del-desiran for the Treatment of DM1

FROM A PARENT STUDY Key Inclusion Criteria: * Completion of any prior AOC 1001 studies with satisfactory completion of dosing and follow-up assessments and satisfactory compliance with the protocol requirements of the parent study, as determined by the Investigator. Key Exclusion Criteria: * Breastfeeding, pregnancy, or intent to become pregnant during the study. * Unwilling to comply with contraceptive requirements. * Any new conditions or worsening of existing condition that in the opinion of the Investigator would make the participant unsuitable for the study. FIXED-DOSE PK COHORT Key Inclusion Criteria: * Clinical and genetic diagnosis of DM1 and clinically significant hand myotonia. Key Exclusion Criteria: * Breastfeeding, pregnancy, or intent to become pregnant during the study * Unwilling to comply with contraceptive requirements * Abnormal lab values, conditions or diseases that would make the participant unsuitable for the study * Diabetes that is not adequately controlled * History of decompensated heart failure within 3 months of screening. Participants with preexisting pacemaker/ICD are not excluded * Body Mass Index \> 35 kg/m2 at Screening * Recently treated with an investigational drug or biological agent Note: Additional protocol defined Inclusion and Exclusion criteria apply