What is Strensiq - Asfotase alfa and what is it used for?
Strensiq is a medicine used in the long-term treatment of patients with hypophosphatasia in childhood. Hypophosphatasia is a rare inherited bone disease, which can lead to early tooth loss, bone malformations, frequent bone fractures and breathing difficulties. Strensiq contains the active ingredient asfotase alfa.
Because the number of patients with hypophosphatasia is low, the disease is considered "rare" and Strensiq was designated an "orphan medicine" (a medicine used in rare diseases) on 3 December 2008.
How is Strensiq - Asfotase alfa used?
Strensiq can only be obtained with a prescription and treatment must be started by a doctor experienced in the treatment of metabolic disorders or bone diseases.
The medicine is available as a solution for injection in vials of different dosage and volume. It is given by subcutaneous injection six times a week (at a dose of 1 mg / kg body weight) or three times a week (at a dose of 2 mg / kg body weight). Since the amount of medicine to be administered depends on the patient's body weight, the doctor must adjust the dose with the change in weight, especially in growing children. For more information, see the package leaflet.
How does Strensiq - Asfotase alfa work?
Hypophosphatasia is caused by defects in the gene responsible for producing an enzyme, called "non-specific alkaline phosphatase" (ALP), which plays a fundamental role in the formation and maintenance of healthy bones, as well as in the management of calcium and phosphate in the body. Individuals with hypophosphatasia lack a sufficient number of functioning ALP enzymes and therefore have a weak bone structure. Asphotase alfa, the active ingredient in Strensiq, is a modified copy of the human ALP enzyme and is used to replace the deficient enzyme, in order to increase the concentration of functional ALPs.
What benefit has Strensiq - Asfotase alfa shown during the studies?
Strensiq has been studied in a main study involving 13 children aged between six and 12 years of age. Strensiq was administered at a dose of 2 mg / kg or 3 mg / kg of body weight three times a week, for 24 weeks. The main measure of effectiveness of the medicine was the improvement in the appearance of the wrist and knee joints in patients, observed on X-ray before and after treatment with Strensiq. Radiographs of children treated with Strensiq were also compared with similar radiographs taken on 16-year-old boys not treated with Strensiq ("historical checks"). The study, which also considered other parameters of efficacy, including growth and height, showed that in children treated with Strensiq the joint structure had improved, as evidenced by radiographs, and that most patients appeared to have grown in height . In the historical controls, similar improvements in the articular level or in terms of height growth in a comparable time frame were not detected in most patients.
The effectiveness of Strensiq was also confirmed, in general, by further minor studies, in some of which the dose of 1 mg / kg of Strensiq administered six times a week was also examined.
What is the risk associated with Strensiq - Asfotase alfa?
The most common side effects with Strensiq (which may affect more than 1 in 10 people) are headache, erythema (redness of the skin), pain in the arms and legs, fever, irritability, reactions at the injection site (pain, rash and itching) and bruising (bruising). For the full list of restrictions and side effects reported with Strensiq, see the package leaflet.
Why has Strensiq - Asfotase alfa been approved?
The Agency's Committee for Medicinal Products for Human Use (CHMP) decided that Strensiq's benefits are greater than its risks and recommended that it be approved for use in the EU. The committee noted that hypophosphatasia is a serious and life-threatening disease, for which there are no authorized therapies. Although the main study was conducted on a small scale and without directly comparing Strensiq with another treatment or with untreated patients, the CHMP considered that the observed improvement in bone and apparent growth represented important benefits. Since hypophosphatasia is an extremely rare disease, data referring to this population is likely to remain limited. As for safety, reactions at the injection site and other side effects were considered manageable with current recommendations.
Strensiq was authorized in "exceptional circumstances" because it was not possible to obtain complete information on the medicine due to the rarity of the disease. Every year the European Medicines Agency will review the new information available and this summary will be updated accordingly
What information is still awaited for Strensiq - Asfotase alfa?
As Strensiq has been approved in exceptional circumstances, the company that markets it will set up a register of patients with hypophosphatasia to collect information on the disease and on Strensiq's safety and efficacy over the long term.
What measures are being taken to ensure the safe and effective use of Strensiq - Asfotase alfa?
A risk management plan has been developed to ensure that Strensiq is used as safely as possible. Based on this plan, safety information has been included in the summary of product characteristics and the package leaflet for Strensiq, including the appropriate precautions to be followed by healthcare professionals and patients.
In addition, the company will provide information material to patients and caregivers to ensure that Strensiq is used correctly and to minimize the risk of medical errors. The material will contain a self-injection guide for patients, as well as instructions on how to inject for use by parents or caregivers of children with the disease.
The company will also carry out a study to collect data on the reactions of adult patients treated with the Strensiq dose used in the pediatric population. Ongoing studies will also continue to further examine the benefit of Strensiq in adolescents aged 13 to 18 years.
More information on Strensiq - Asphotase alfa
For the full version of the EPAR and the summary of the Strensiq risk management plan, consult the website of the Agency: ema.Europa.eu/Find medicine / Human medicines / European public assessment reports. For more information on Strensiq therapy, read the package leaflet (also part of the EPAR) or contact your doctor or pharmacist.
