ALXN2350 in Adult Participants With BAG3-Associated Dilated Cardiomyopathy

Inclusion Criteria:

* Pathogenic or likely pathogenic mutation in BAG3
* Medical history of diagnosis of DCM
* Stable combination of HF SoC medications
* Adequate acoustic windows for echocardiography
* LVEF \> 15% and ≤ 45% at Screening by echocardiography
* Diagnosis of chronic HF for at least 3 months
* NYHA Class I/II/III at Screening

Exclusion Criteria:

* Presence of antibodies to AAV9
* Presence of a pathogenic or likely pathogenic variant in another gene where that other gene is authoritatively recognized as causal for DCM
* Decompensated HF
* Cardiac ventricular arrhythmia that requires treatment
* History of untreated clinically significant valve disease or a Screening confirmation of severe aortic stenosis, severe mitral stenosis, moderate or severe aortic insufficiency or severe mitral insufficiency
* NYHA Class IV
* History of substance abuse that could contribute to cardiac dysfunction

Note: Other inclusion and exclusion criteria may apply.