SGLT2 Inhibitors in Transthyretin Amyloid Cardiomyopathy

Transthyretin amyloid cardiomyopathy (ATTR-CM) is an underrecognized cause of heart failure among older adults, in which misfolded transthyretin (TTR) proteins build up in the muscle tissue of the heart. In 2018, a drug called tafamidis was proven to stabilize the protein and protect people from further damage, and in 2019, it was approved for use in ATTR-CM by the U.S. Food and Drug Administration (FDA). But while people with ATTR-CM are living longer, they continue to suffer from symptoms of heart failure and cardiorenal syndrome as the disease progresses. Sodium glucose co-transporter inhibitors (SGLT2i) are drugs used to treat diabetes mellitus, heart failure, and chronic kidney disease. They may also reduce systemic inflammation, and affect body composition (fat, lean mass, and total water contents) in patients with heart failure, a condition which also has significant overlap with obesity. No one has explored the safety, tolerability, and clinical effects of SGLT2i in patients with heart failure due to ATTR-CM.

Inclusion criteria

• Every participant must meet all of the following inclusion criteria to be eligible for enrollment in this study:

• Age ≥ 18 years old
• Diagnosis of TTR cardiac amyloidosis (wild type or variant), confirmed by the presence of amyloid deposits on analysis of biopsy specimens obtained from cardiac and noncardiac sites (e.g. fat aspirate, gastrointestinal sites, salivary glands, or bone marrow), technetium-99m pyrophosphate cardiac scintigraphy, or mass spectrometry
• Normal serum free light chain ratio and the absence of abnormal monoclonal band on serum and urine immunofixation
• Subjects will have at least 1 of the indications below for an SGLT2i, and meet package-insert criteria for drug initiation: non-insulin dependent diabetes mellitus with hemoglobin A1c ranging from 6.5-9.9 OR chronic kidney disease (defined as an estimated glomerular filtration rate of 25-75 ml/minute/1.73 m2 of body-surface area)
• On stable oral diuretics (defined as no more than a 50% increase from baseline diuretic dose established during a sustained 2 week period) within 2 weeks before enrollment
• Able to understand and sign the informed consent document after the nature of the study has been fully explained

Exclusion criteria

• The presence of any of the following excludes eligibility for enrollment in this study:

• Prior liver or heart transplantation
• Active malignancy or non-amyloid disease with expected survival of less than 1 year
• Heart failure, in the opinion of the investigator, primarily caused by severe left-sided valve disease. Note: if valve was repaired, subject may be considered as no longer with severe valve disease
• Heart failure, in the opinion of the investigator, primarily caused by ischemic heart disease
• Ventricular assist device or anticipated within the next 6 months
• Pacemaker or implantable cardioverter defibrillator incompatible with magnetic resonance technology
• Absolute contraindication for quantitative magnetic resonance (e.g. aneurysmal clips, metal objects)
• Impairment from stroke, injury or other medical disorder that precludes participation in the study
• Myocardial infarction, cardiovascular surgery, stroke or transient ischemic attack within the prior 90 days
• Disabling dementia or other mental or behavioral disease
• Enrollment in a clinical trial not approved for co-enrollment
• Expected use of continuous intravenous inotropic therapy in the next 6 months
• High risk for non-adherence as determined by screening evaluation
• Inability or unwillingness to comply with the study requirements
• Chronic kidney disease with estimated glomerular filtration rate (eGFR) <15 mL/min/1.73 m2 or end-stage renal disease
• Current or prior SGLT2i use
• Type 1 diabetes mellitus or insulin-dependent diabetes mellitus
• N-terminal (NT)-pro hormone BNP (NT-proBNP) < 300 pg/mL or < 900 pg/mL if concomitant diagnosis of atrial fibrillation
• History of ketoacidosis
• History of complex urinary tract or genital infections
• History of kidney stone
• Systolic blood pressure < 90 mmHg and symptomatic hypotension
• Systolic blood pressure ≥ 180 mmg Hg
• Chronic obstructive pulmonary disease
• Major surgery in the 90 days before or after screening
• Chronic alcohol or drug abuse
• Nursing home resident
• Other reason that would make the subject inappropriate for entry into this study