The National Institute for Health and Care Excellence has published draft guidelines that restrict the use of Alexion's £366,912-a-year enzyme replacement therapy Strensiq by the National Health Service in treating patients with hypophosphatasia.

The cost watchdog is currently recommending Strensiq (asfotase alfa) as an option for treating the bone manifestations of hypophosphatasia, but only in people with perinatal- and infantile-onset disease, as per conditions set out in the proposed managed access agreement, and when the company provides the therapy with the proposed discount and annual per-patient cost cap.

Strensiq is not recommended for treating the bone manifestations of hypophosphatasia in children with juvenile-onset disease, which has much lower mortality rate than cases appearing in infancy, where 100 percent percent of those diagnosed in the first six months of their lives die before they reach one year. But later forms are often linked with debilitating and lead to bone deformities that may result in delayed walking, limb weaknesses, skeletal pain and non-traumatic fractures.

The current mainstay of treatment is supportive care aiming to monitor and alleviate symptoms, and enzyme replacement therapy Strensiq (asfotase alfa) is the first treatment to specifically target the underlying cause of the disease.

However, while the committee considered that the therapy could "provide important clinical benefits" for this patient group, given its "very high" cost and the "significant uncertainties about its long-term benefits, who would benefit the most from treatment, and the number of people in this patient group who might be eligible for treatment," it could not endorse its use in this setting.

Strensiq was also knocked back by the Institute for treating the bone manifestations of hypophosphatasia in adults with juvenile-onset disease.

Alexion said it is extremely disappointed with the recommendations, and is "concerned that NICE has fundamentally failed to fairly and appropriately evaluate the benefits of Strensiq for patients with paediatric-onset hypophosphatasia (HPP)."

Restricting access to patients with perinatal- and infantile-onset HPP will deny the very small number of children, juveniles and adults, who are unnecessarily suffering serious life-limiting complications of HPP, access to the only proven treatment, it argued.

In making its decision, NICE has "completely disregarded the proposed consensus managed access agreement for children, juveniles and adults with paediatric-onset disease, which was developed by physician thought-leaders, patient groups, and NHS England, with input from Alexion Medical, and that identified those patients who experience the most disabling symptoms and are expected to derive most benefit from therapy".

The decision "directly calls into question the effectiveness of the entire highly specialised technology (HST) assessment process and the value of stakeholder input provided," the firm stressed, noting that the process for review "has not been timely – taking over a year to reach this point – or conducive to constructive discussion, negotiation or resolution on behalf of the very small number of patients with HPP that require access to Strensiq."

Alexion said its priority now is to ensure that the very small number of patients with severely debilitating HPP in England have access to Strensiq, just like patients in the US, Germany and Japan, and that it is "considering all potential procedural and other options available".