A Study of ARRY-371797 in Patients With LMNA-Related Dilated Cardiomyopathy

Key Inclusion Criteria:

- Patients with idiopathic dilated cardiomyopathy and stable New York Heart Association
(NYHA) Class II - IIIa congestive heart failure (CHF).

- Stable, guidelines-based medical and device therapy, without any CHF hospitalizations
or change in heart failure drug dose with ≥ 50% reduction in dose or ≥ 100% increase
in dose in the past 3 months.

- Left ventricular (LV) end diastolic diameter by trans-thoracic echocardiography of >
3.3 cm/m2 (for females) or 3.4 cm/m2 (for males) and/or LV ejection fraction ≤ 45%.

- Gene positive for a pathogenic mutation in the LMNA gene, as determined by a
CLIA-certified clinical laboratory (mutations including but not limited to:
splice-site, non-sense, deletion mutations, a mis-sense mutation in a highly
conserved codon, a mis-sense mutation involving a major charge change, a mis-sense
mutation previously associated with genetic dilated cardiomyopathy).

- Within 3 weeks prior to first dose of study drug, completed distance during six
minute walk test of ≥ 100 m and ≤ 350 m AND/OR ≥ 100 m and ≤ 450 m AND ≤ 60%
predicted distance AND patient is symptomatic for dilated cardiomyopathy per
Investigator judgment.

- On the day before and day of first dose of study drug, completed distance during six
minute walk test of ≥ 100 m and ≤ 400 m (with the greater value within 10% of the
lesser value) AND/OR ≥ 100 m and ≤ 475 m (with the greater value within 10% of the
lesser value) AND patient is symptomatic for dilated cardiomyopathy per Investigator
judgment.

- Acceptable hematology, hepatic and renal function laboratory values within 3 weeks
prior to first dose of study drug.

- Additional criteria exist.

Key Exclusion Criteria:

- Unstable clinical cardiac symptoms requiring unscheduled hospitalization within 60
days prior to study start.

- Clinically significant coronary artery disease, as per Investigator judgment.

- Currently receiving continuous intravenous (IV) inotrope infusion, or presence of a
ventricular assist device, or history of prior heart transplantation.

- Any of the following within 60 days prior to study start: Myocardial infarction,
cardiac surgical procedures, acute coronary syndrome, hemodynamically destabilizing
cardiac arrhythmia, serious systemic infection with evidence of septicemia, any major
surgical procedure requiring general anesthesia.

- Uncorrected, hemodynamically significant primary valvular disease.

- Initiation of cardiac resynchronization therapy within 180 days prior to study start.

- Likelihood, in the Investigator's opinion, of undergoing cardiac transplantation,
left ventricular assist device or other device implantation, or other cardiac surgery
within the next 6 months; or of requiring continuous IV inotropic treatment, or
referral for hospice or end-of-life treatment.

- Active malignancy (except surgically-curative basal cell carcinoma, squamous cell
carcinoma, or cervical carcinoma).

- Receiving chronic immunosuppressant therapy.

- Known positive serology for the human immunodeficiency virus (HIV), active hepatitis
B and/or hepatitis C.

- Participation in any other investigational study of drugs or devices within 30 days
prior to study start.

- Additional criteria exist.