According to a recent press release from Pfizer and biotechnology company Vivet Therapeutics, VTX-801, a gene therapy candidate for patients with Wilson disease, recently received Fast Track designation from the FDA. This designation is designed to help get drugs into patients’ hands sooner. Overall, the Fast Track process, requested by drug developers, aims to facilitate and expedite drug development and review for drugs designed to fill unmet medical needs or treat serious conditions. In short, the designation is granted to drugs which could improve survival and functioning, provide a new therapy, or offer benefits over available therapies. As a result, drug developers also receive a variety of benefits, such as increased FDA communication and rolling review. 

VTX-801

So what exactly is VTX-801? Vivet Therapeutics describes this gene therapy, delivered via a singular intravenous infusion, as: 

an adeno-associated virus (AAV) containing a gene coding for a functional mini-ATP7B copper transporter, that is intended to restore copper metabolism through liver cell targeting.

In preclinical studies involving mice models of Wilson disease, VTX-801 reduced copper buildup within the brain, balanced copper levels, and reversed negative hepatologic effects. So far, the treatment has also received Orphan Drug designations within the U.S. and E.U. 

Moving forward, researchers hope to evaluate the safety, efficacy, pharmacological basis, and tolerability of VTX-801 within the Phase 1/2 GATEWAY trial. Altogether, 16 patients are expected to enroll. During the trial, researchers will analyze three different VTX-801 doses to determine the best option for treatment and further testing. 

Wilson Disease

Sometimes referred to as Wilson’s disease or hepatolenticular degeneration, Wilson disease is a genetic condition which prevents the body from metabolizing or excreting copper. There are over 300 ATP7B gene mutations which may cause Wilson disease. Normally, some copper in our bodies plays a role in our good health. However, these gene mutations cause copper to accumulate in the brain, liver, and organs in patients with Wilson disease. Ultimately, this accumulation causes negative health effects, from hepatitis to psychiatric disturbances. While this condition can affect people of all ages, many diagnoses occur between ages 6 and 45. 

Symptoms of Wilson disease include:

• Jaundice (yellowing of the skin and eyes)
• Difficulty swallowing or walking
• Easy bruising and bleeding
• Neutropenia (low white blood cell count)
• Anemia (low red blood cell count)
• Excessive fatigue
• Confusion
• Fluid buildup in the extremities
• Abdominal swelling
• Hepatitis
• Esophageal varices (abnormal blood vessels in the esophagus which may bleed)
• Kayser-Fleisher ring (brown ring around the iris)
• Changes in behavior, mood, or personality, including depression and suicidal ideation

While Wilson disease can be fatal without therapy, there are treatment options available. These include medications to remove copper from the blood, zinc supplement, and a low-copper diet. Learn more about Wilson disease.