Patisiran (marketed as Onpattro) can improve the functional capacity of patients with transthyretin amyloid cardiomyopathy (ATTR-CM), according to a study recently published in JACC Journals.
Patisiran is a medication that helps stop misfolded proteins from forming, thus addressing the key driver of heart disease in ATTR-CM. Patisiran has been approved to treat transthyretin amyloid polyneuropathy (ATTR-PN); its use in ATTR-CM is off-label.
One of the long-terms effects of ATTR-CM is that patients lose the functional capacity to carry out activities of daily living, such as walking, carrying objects, and exercising. Functional capacity is most commonly measured using the six-minute walk test (6MWT), which (as its name suggests) is a test to see how far a patient can walk independently for six minutes.
A team of medical researchers sought to investigate if the use of patisiran resulted in improved functional capacity as measured by the 6MWT.
Investigators conducted an international study to assess the efficacy and safety profile of patisiran in patients with ATTR-CM within a 12-month window. Aside from the 6MWT, investigators measured health status and quality of life via the Kansas City Cardiomyopathy Questionnaire Overall Summary (KCCQ-OS), which contains questions on how the disease affects various areas of life, such as physical health and social well-being.
Read more about ATTR-CM testing and diagnosis
In this study, called the APOLLO-B, 360 patients were recruited. A total of 179 patients received the placebo, while 181 patients received patisiran.
This study showed that more patients treated with patisiran experienced clinically meaningful improvements in their KCCQ-OS score after 12 months compared with those on the placebo (34% vs 24%). In addition, patients who were on the placebo had a greater deterioration in the KCCQ-OS score across every measure compared to patients who were on patisiran. Patisiran users also had significant improvements in health status and quality of life.
Patients on patisiran consistently experienced improvements in most of the physical activities covered by the KCCQ, except for the “ability to dress oneself”; these included walking, jogging and climbing stairs.
The key finding of this study is that patients on patisiran experienced significant improvements in 6MWT distance across a number of thresholds; for example, a higher proportion of patients treated with patisiran saw their 6MWT improve by 15 meters (about 50 feet) or more compared with those on the placebo.
“Overall, the benefit observed with the 6MWT in APOLLO-B translates into a clinically meaningful impact in the lives of patients,” the investigators wrote.
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