MedStar Health Launches Participation in Phase 3 MAGNITUDE Gene-Editing Study with First U.S. Heart Patient Treated at MedStar Washington Hospital Center

MedStar Health Launches Participation in Phase 3 MAGNITUDE Gene-Editing Study with First U.S. Heart Patient Treated at MedStar Washington Hospital Center

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Dr. Farooq Sheikh

Study examines if gene editing can help people living with transthyretin amyloidosis with cardiomyopathy (ATTR-CM)

WASHINGTON – The first U.S. heart patient involved in a study for a new gene-editing therapy directly infused inside the body has successfully been enrolled at MedStar Washington Hospital Center. The pivotal, international clinical trial is evaluating the safety and efficacy of a gene-editing treatment for patients with transthyretin amyloidosis with cardiomyopathy (ATTR-CM), an under-recognized cause of heart failure.

The clinical trial, known as MAGNITUDE, is a Phase 3, multinational, multicenter, double-blind, placebo-controlled trial that is evaluating the efficacy and safety of a single infusion of a gene-editing therapy in patients with ATTR-CM. Transthyretin amyloidosis is a protein disorder that typically affects the heart by stiffening the muscle and making it harder for the heart to pump blood throughout the body. The treatment is designed to prevent the production of an abnormal form of a protein called transthyretin (TTR) that causes the disease.

In ATTR, the TTR protein accumulates and builds up in different parts of the body, particularly in the heart and nerves. The buildup is known as amyloidosis. When TTR amyloidosis is in the heart, it is known as ATTR-CM, a life-threatening condition.

Participants in the study will be assigned at random to receive either the research medication called NTLA-2001 or a placebo, which has no active ingredients. NTLA-2001 contains a gene-editing system known as CRISPR/Cas9. It is designed to find and disable the TTR gene in the liver where most TTR protein is produced. NTLA-2001 is given as a one-time intravenous infusion.

“It is with great excitement that our center has enrolled the first U.S. patient in the MAGNITUDE trial, a pivotal study assessing a new avenue of treatment for human diseases, specifically ATTR-CM,” said Farooq Sheikh, MD, medical director of the Advanced Heart Failure Program at MedStar Washington Hospital Center and principal investigator of the MAGNITUDE study. “The MedStar Health Infiltrative Cardiomyopathy/Advanced Heart Failure Program is passionate about improving the lives of our patients in the region and beyond.”

NTLA-2001 is the first investigational CRISPR therapy to be administered intravenously to edit genes inside the human body. Interim Phase 1 and 2 clinical trial data showed the administration of NTLA-2001 led to consistent and long-lasting transthyretin (TTR) protein reduction.

There are an estimated 50,000 people worldwide living with hereditary ATTR amyloidosis and between 200,000 and 500,000 people with wild-type ATTR amyloidosis, which typically impacts the heart, leading to ATTR-CM. There is no known cure.

The MAGNITUDE study is expected to enroll approximately 765 participants worldwide and represents one of the more 175 cardiovascular research studies conducted at MedStar Health annually. For more information about the study, visit or contact study coordinator Hellina Birru, MD, at

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