Strensiq logo Mechanism of action STRENSIQ® (asfotase alfa) is indicated for long-term enzyme replacement therapy in patients with paediatric-onset hypophosphatasia (HPP) to treat the bone manifestations of the disease.1 To date, this is the first and only approved treatment in this indication,2–4 supported by up to 7 years of clinical data.2–7

This medicinal product is subject to additional monitoring. This will allow quick identification of new safety information. Please report any adverse events via your national reporting system. Adverse events can also be reported to Alexion Pharmaceuticals by contacting:
https://contactazmedical.astrazeneca.com.
Please refer to the Summary of Product Characteristics for further information.
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  • In HPP, deficiency in the activity of the enzyme TNSALP leads to harmful accumulation of substrates PPi and PLP, impairing bone mineralisation and vitamin B6 metabolism, respectively8–11
  • By replacing TNSALP, STRENSIQ® may promote bone mineralisation and a decrease in elevated TNSALP substrate levels, namely PPi and PLP1,6,7,11
  • With STRENSIQ®, the median serum ALP activity can rise well above the upper limit of normal (age and sex dependent normal range) and may be sustained over time with subcutaneous dosing2,6
ALP, alkaline phosphatase; PLP, plasma/serum pyridoxal 5′-phosphate; Pi, inorganic phosphate; PPi, inorganic pyrophosphate; TNSALP, tissue non-specific alkaline phosphatase.
This medicinal product has been authorised under ‘exceptional circumstances’. This means that due to the rarity of the disease it has not been possible to obtain complete information on this medicinal product.

▼This medicinal product is subject to additional monitoring. This will allow quick identification of new safety information. Please report any adverse events via your national reporting system. Adverse events can also be reported to Alexion Pharmaceuticals by the following link: https://contactazmedical.astrazeneca.com/
STRENSIQ® Summary of Product Characteristics. Alexion Europe SAS. Available at https://www.ema.europa.eu/en/documents/product-information/strensiq-epar-product-information_en.pdf. Last accessed: June 2025. Whyte MP, et al. Asfotase alfa for infants and young children with hypophosphatasia: 7 year outcomes of a single-arm, open-label, phase 2 extension trial. Lancet Diabetes Endocrinol. 2019;7(2):93–105. European Medicines Agency. EPAR for Strensiq. 2024. Available at: https://www.ema.europa.eu/en/medicines/human/EPAR/strensiq#product-info. Last accessed: June 2025. Jaswanthi N, et al. Effect of Asfotase Alfa in the Treatment of Hypophosphatasia- A Systematic Review. J Pharm Bioallied Sci. 2023;15(Suppl 1):S101-S104. Hofmann CE, et al. Efficacy and Safety of Asfotase Alfa in Infants and Young Children With Hypophosphatasia: A Phase 2 Open-Label Study. J Clin Endocrinol Metab. 2019;104(7):2735–2747. Whyte MP, et al. Asfotase alfa therapy for children with hypophosphatasia. JCI Insight. 2016;1(9):e85971. Kishnani PS, et al. Five-year efficacy and safety of asfotase alfa therapy for adults and adolescents with hypophosphatasia. Bone. 2019;121:149–162. Rockman-Greenberg C. Hypophosphatasia. Pediatr Endocrinol Rev. 2013;10(suppl 2):380–388. Whyte MP. Hypophosphatasia. Nature’s Window on Alkaline Phosphatase Function in Humans. In: Bilezikian JP, et al. eds. Principles of Bone Biology, Two-Volume Set. San Diego, CA: Elsevier; 2008. p.1573–1598. Orimo H. The Mechanism of Mineralization and the Role of Alkaline Phosphatase in Health and Disease. J Nippon Med Sch. 2010;77(1):4–12. Bowden SA, Foster BL. Profile of asfotase alfa in the treatment of hypophosphatasia: design, development, and place in therapy. Drug Des Devel Ther. 2018;12:3147–3161.