US FDA approves Nexviazyme for late-onset Pompe disease

The US Food and Drug Administration (FDA) has approved Nexviazyme for the treatment of patients aged one year and older with late-onset Pompe disease, a progressive and debilitating muscle disorder that impairs a person’s ability to move and breathe. Nexviazyme is an enzyme replacement therapy (ERT) designed to specifically target the mannose-6-phosphate (M6P) receptor, the key pathway for cellular uptake of enzyme replacement therapy in Pompe disease. Nexviazyme has been shown in clinical trials to provide patients with improvements in respiratory function and walking distance, Sanofi said in a statement.

“Pompe disease is a debilitating and progressive condition that significantly inhibits mobility and breathing,” said Bill Sibold, Executive Vice President, Sanofi Genzyme.

He also said, “For decades, we’ve made it our responsibility to research how to target the M6P receptor, the key pathway for cellular uptake of enzyme replacement therapy. Nexviazyme is a potential new standard of care for people living with late-onset Pompe disease and delivers on our promise to pursue medicines for patients living with rare diseases.”

Pompe disease affects an estimated 3,500 people in the United States and can present as infantile-onset Pompe disease (IOPD), the most severe form of Pompe disease with rapid onset in infancy, and late-onset Pompe disease (LOPD), which progressively damages muscles over time.

Pompe disease is caused by a genetic deficiency or dysfunction of the lysosomal enzyme acid alpha-glucosidase (GAA), which results in build-up of complex sugars (glycogen) in muscle cells throughout the body. The accumulation of glycogen leads to irreversible damage to the muscles, including the diaphragm that supports respiratory function and skeletal muscles that affect mobility, functional endurance and breathing, notified the statement.

“Nexviazyme is a new and exciting therapeutic option for people with late-onset Pompe disease,” said Mazen M Dimachkie, MD, FAAN, FANA, Professor of Neurology, Chief of the Neuromuscular Division and Executive Vice Chair of the Department of Neurology at the University of Kansas Medical Center. “The phase-III study results showed meaningful improvements in respiratory function and walking distance, which are impactful in this serious condition.”

When compared to baseline, patients treated with Nexviazyme had a 2.9-point improvement (SE=0.9) in forced vital capacity (FVC) percent-predicted at week 49, the study’s primary endpoint. Patients treated with Nexviazyme had a 2.4-point greater improvement in FVC per cent-predicted compared to patients treated with alglucosidase alfa at week 49 meeting the measurement of non-inferiority (p=0.0074; 95% CI, -0.13, 4.99). Statistical superiority of Nexviazyme over alglucosidase alfa was not achieved (p=0.06), mentioned the statement.

It added that a key secondary endpoint in the trial measured functional endurance with the 6-minute walk test (6MWT). When compared to baseline, patients treated with Nexviazyme walked 32.2 metres farther (SE=9.9) at week 49. Patients treated with Nexviazyme walked 30 metres farther (95% CI, 1.33, 58.69) than patients treated with alglucosidase alfa at week 49. As per the hierarchy of the study protocol, formal statistical testing for all secondary endpoints was not conducted.

It further mentioned that during the double-blind active-controlled period of 49 weeks, serious adverse reactions were reported in two patients (two per cent) treated with Nexviazyme and in three (six per cent) patients treated with alglucosidase alfa. The most frequently reported adverse reactions (over five per cent) in Nexviazyme-treated patients were headache, pruritus (itching sensation), nausea, hives and fatigue.

Infusion-associated reactions were reported in 13 (25 per cent) of the Nexviazyme-treated patients and in 16 ( 33 per cent) of patients treated with alglucosidase alfa. Infusion-associated reactions reported in more than one patient on Nexviazyme were mild to moderate and included headache, diarrhoea, itching, hives and rash. None of the infusion-associated reactions were severe.

The statement also said that Nexviazyme is administered as a monotherapy ERT every two weeks. The recommended dose is based on body weight (20 mg/kg for LOPD patients ≥30 kg or 40 mg/kg for LOPD patients <30 kg) and is administered incrementally via intravenous infusion. It is expected to be available in the US in the coming weeks.