Transthyretin Amyloidosis Treatment; Depends on Which Tissues Are Affected and How Far the Disease Has Progressed

There is no cure for transthyretin amyloidosis (ATTR amyloidosis). Transthyretin amyloidosis treatment for the disease is a two-fold process, such as treat the underlying cause and manage symptoms. Transthyretin amyloidosis is a systemic, life-threatening disease characterized by transthyretin (TTR) fibril deposition in organs and tissue. It is a rare disease characterized by the abnormal buildup of amyloid deposits composed of misfolded transthyretin protein in the body's organs and tissues. There are two types of transthyretin amyloidosis, such as wild type transthyretin amyloidosis and hereditary transthyretin amyloidosis.

Hereditary transthyretin amyloidosis is further divided into cardiomyopathy, polyneuropathy, and mixed type. The transthyretin amyloidosis treatment involves disease modification with the U.S. Food and Drug Administration (USFDA) approved agents, inotersen, tafamidis, and patisiran. These drugs work by slowing the progression of amyloid disease but are not a cure. Inotersen and patisiran are approved for treatment of polyneuropathy caused by hereditary transthyretin-related amyloidosis (hATTR) in adults, and tafamidis is approved for treatment of transthyretin-mediated amyloid cardiomyopathy (ATTR-CM).

Transthyretin amyloidosis is so rare that it is estimated to affect one in 100,000 Americans of European descent. However, the exact incidence of transthyretin amyloidosis is unknown. A positive TcPYP scan (technetium pyrophosphate muscle scan), along with urine and blood tests may rule out other forms of amyloidosis, confirming the diagnosis without the need for a heart biopsy. A blood test is used to find out the type of transthyretin amyloidosis (wild-type or hereditary), when transthyretin amyloidosis is confirmed. The disease can be diagnosed by various approaches such as imaging, molecular and genetic testing, and histopathology.

Transthyretin is a transport protein and is created in the liver. Its job is to carry retinol (vitamin A) and thyroxine (thyroid hormone) to the places where they are needed in the body. It is a primary transport protein for thyroxine and retinol. Transthyretin amyloidosis is a result of transthyretin being produced by the liver and forming dimers, followed by monomers. Mutated transthyretin is associated with the formation of amyloid fibrils, leading to the development of TTR-related amyloidosis (ATTR). Thus, there is an increasing demand for safe and effective transthyretin amyloidosis treatment worldwide.