Heart failure and atrial fibrillation, two of the most common cardiac diagnosis of the elderly population. It is now clear that a condition called “amyloidosis” is an important cause of both of these conditions. Previously underdiagnosed, amyloidosis is a disease where proteins can change shape and inappropriately deposit in organs. When it affects the heart, the condition is called amyloid “cardiomyopathy”. It is characterized by deposits of amyloid protein fibrils in the walls of the heart including the left ventricle– the main blood pumping chamber. These amyloid protein deposits cause the heart walls to become stiff inhibiting their ability to properly relax to fill with blood and adequately squeeze to pump blood out of the heart.
One of the two main types of amyloid cardiomyopathy is transthyretin amyloid cardiomyopathy or ATTR-CM. ATTR-CM is a progressive, underdiagnosed, potentially fatal disease. There are two diagnosable types of ATTR-CM: hereditary and wild-type. In hereditary ATTR-CM, there is a mutation in the transthyretin gene which can be passed down from parent to offspring. Amyloid deposits in the heart, nerves, and sometimes the kidneys and other organs are a defining characteristic. Wild-type ATTR-CM, or acquired ATTR-CM, doesn’t run in families and is not due to a mutation in the transthyretin gene. Symptoms of wild-type ATTR-CM include carpal tunnel syndrome and pain/numbness in the hands and feet and usually occur after the age of 65. But no matter the subtype, if left untreated, ATTR-CM affects heart function to the point of failure.
Previously, no medication existed for the treatment of either type of ATTR-CM. Treatment for the condition was limited to an unlikely heart transplant. But in May 2019, an approval provided hope for the suffering population. Approval of two drug formulations of the compound known as tafamidis dubbed the first ever treatment for both hereditary and wild-type ATTR-CM. The two drugs are approved for ATTR-CM in adults to reduce cardiovascular mortality and cardiovascular-related hospitalization.
Approval comes by way of Phase III Clinical Trial results showing 30% reduced risk of death in patients on the therapy. The therapy received Breakthrough Therapy Designation and eventual approval one year after these topline results. The approval of a drug for these conditions effectively highlights the importance of rare disease research – an avenue to providing patients an option where there once was none. Through therapies like these, we’re able to mitigate the impact of both acquired and genetic disorders, and not only improve survival for patients but preserve their quality of life.