European regulators have waved through two long-term enzyme replacement therapies developed by Alexion Pharmaceuticals, giving patients with the targeted metabolic disorders access to treatment for the first time.

The European Commission has approved Kanuma (sebelipase alfa) for patients with lysosomal acid lipase deficiency (LAL-D) and Strensiq (asfotase alfa) for paediatric-onset hypophosphatasia (HPP) to treat the bone manifestations of the disease. 

Both are classified ultra-rare diseases as they occur in less than 20 patients per one million in the general population.

LAL-D is a genetic condition causing chronic build-up of cholesteryl esters and triglycerides in the liver, blood vessel walls and other tissues, leading to multi-organ damage and premature death. 

“In clinical studies, 67% of infants treated with Kanuma survived beyond 12 months of age, whereas without treatment, these patients would have faced a near-certain fatal outcome,” noted study investigator Vassili Valayannopoulos, Hôpital Necker-Enfants Malades and IMAGINE Institute, Paris, highlighting its potential.

HPP is a genetic condition characterised by defective bone mineralisation that can lead to destruction and deformity of bones, profound muscle weakness, seizures, respiratory failure and premature death. Clinical data show that Strensiq induced rapid and sustained improvements in bone mineralisation, the company noted.

Pricing strategy

Given that Alexion also sells the world’s most expensive drug Soliris (eculizumab), a rare disease therapy which costs around $500,000 per patient per year, all eyes will now be on the price tags for Kanuma and Strensiq and whether they will be acceptable to reimbursement bodies.

While its pricing strategy hasn’t yet been revealed, according to Fierce Biotech, Barclays analyst Geoff Meacham believes the drugs will both be charged at around $375,000 a year, bringing in combined peak sales of around $2 billion a year. 

Regulators across the pond are also currently mulling over whether to approve the ERTs, but both have been assigned ‘breakthrough’ status by the Food and Drug Administration.