Strensiq logo Patient experience 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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Three patients, three experiences with STRENSIQ®

Harry6

Male, age 6 years*

A fraternal twin, who at 5 months of age, fell off the growth curve and manifested hypotonia. Deciduous tooth loss began at 18 months and independent walking was delayed, beginning at age 3. He was slower, weaker and had less endurance than his twin brother. On STRENSIQ® therapy: Initiated on 6 mg/kg/week given as three injections.†

†Treatment initiation only – dose reductions or adjustments may have occurred as per protocol.6

5 months

Fell off the growth curve and manifested hypotonia14

Click to see at 18 months

18 months

Premature deciduous tooth loss. Harry also presented to a physician with trouble chewing solids owing to poor muscle strength14

In early childhood, Harry had noticeable growth delays and had difficulties chewing any solid foods owing to poor muscle strength. Harry required occupational and physical therapy through 3 years of age14

Click to see at 3 years

3 years

Impaired gait and, consequently, delayed independent walking. Harry used a walker to ambulate from 2.5 years through to 4 years of age14

Before 6 years of age, Harry had frequent shin and ankle pain and could not jump, hop or run. He was also slower and weaker and had lower endurance compared with his twin brother14

Click to see at 4.5 years

4.5 years

He was diagnosed with infantile HPP at the age of 4.5 years.14

Katie6

Female, age 8 years 8 months*

At 1 year of age, Katie presented with failure to thrive requiring gastrostomy tube placement at 3 years of age, which was later removed at the age of 5. Premature deciduous tooth loss began at 15 months and delayed onset of walking at 26 months. She had below average height and weight. STRENSIQ® therapy was initiated on 6 mg/kg/week, given as three injections.†

†Treatment initiation only – dose reductions or adjustments may have occurred as per protocol.6

12 months

Failure to thrive14

Click to see at 15 months

15 months

Premature deciduous tooth loss14

Click to see at 2 years

2 years

Delayed onset of walking, rachitic rosary, waddling gait and knock knees were all noted14

Click to see at 4 years

4 years

Sagittal suture craniosynostosis14

Click to see at 8 years

8 years

Chiari 1 malformation with thoracic syringomyelia that did not require surgery14

Click to see at 8 years & 8 months

8 years & 8 months

Chronic fatigue after low–mild activity. Katie could only walk two blocks twirling a baton before fatiguing14

Jayde8

Female, age 41 years*

Jayde was diagnosed with infantile-onset HPP at the age of 5 months, presenting with recurrent pneumonia and rib fractures, with additional fractures of the extremities, rickets and short stature. Wheelchair bound due to a non-healing tibial fragility from a fracture sustained 3 years before and also had non-healing femoral subtrochanteric femoral shaft pseudofracture sustained 17 years before. She was edentulous and her height was less than mid-parental height. In 2015, STRENSIQ® therapy was initiated on 1 mg/kg/ subcutaneous injection six times a week.‡

‡Treatment initiation only – dose adjustments may have occurred.8

5 months

Short stature, rickets, multiple fractures of the ribs and extremities, recurring pneumonia. Diagnosed with infantile-onset HPP8

Click to see at 24 years

24 years

Found to have a bilateral subtrochanteric femoral shaft pseudofracture after falling down a flight of stairs. Fracture was treated with intramedullary nail fixation8

Click to see at 38 years

38 years

Short stature. Lacking teeth. Left tibial fragility fracture from stepping off the edge of a pavement. Non-healing fractures and severe bone pain were also present. Jayde’s impaired mobility began to get increasingly worse. She was initially treated with a cast, walking boot, cane and walker. Eventually, Jayde was fully non-weight bearing owing to her nonhealing fractures and became wheelchair-bound8



* Age at treatment initiation. Patient profiles are adapted from published clinical cases, but names and photographs are hypothetical.6 Please note, individual patient experience and outcomes may vary.
Given the vast clinical picture associated with HPP, patients may present to different healthcare professionals along their journey. The team of specialists may vary across different centres and may depend on patient age, individual cases and specific manifestations.9,10


Coordination of care can vary throughout a patient’s life and depending on country of origin and available resources; however, a coordinated, patient-focused approach is consistently recommended.9
Baseline and follow-up assessments during treatment with STRENSIQ® are important and recommended to ensure appropriate management of patients with HPP.9

The recommendations published by Kishnani PS (2017) for the monitoring of patients with HPP being treated with STRENSIQ® were developed based on the consensus of an international expert panel of physicians.* Assessments may vary depending on clinical presentation, prevailing symptoms and national/regional medical practice.9

*These consensus recommendations are based on the expert opinion of an international panel of physicians experienced in the management of HPP. Adherence to these recommendations is completely voluntary. These recommendations are intended to serve as a basic framework for monitoring patients with HPP for whom decision to treat has been made. Ultimately, the treatment and monitoring of patients with HPP should be tailored to the patient based on the individual’ s clinical manifestations, medical history and the clinician’ s professional judgement. Clinicians are advised that the recommendations provided may evolve as more information becomes available.9

Regular assessments can be crucial in guiding treatment decisions for patients with HPP; however, monitoring must be tailored to an individual patient depending on their medical history, clinical presentation and the physician’s expert opinion9
Find out more
ALP, alkaline phosphatase; BPI-SF, The Brief Pain Inventory - Short Form; EQ-5D-5L, EuroQoL 5-Dimension 5-Level; HAQ-DI, Health Assessment Questionnaire Disability Index; HPP, hypophosphatasia; ISR, injection site reaction; LEFS, Lower Extremity Functional Scale; 6MWT, 6-Minute Walk Test; PEA, phosphoethanolamine; PTH, parathyroid hormone; PLP, plasma/serum pyridoxal 5′-phosphate; S36, The 36-Item Short Form Health Survey; TEAE, treatment-emergent adverse event; VAS, Visual Analogue Scale.
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. Klidaras P, et al. Fracture Healing in Two Adult Patients With Hypophosphatasia After Asfotase Alfa Therapy. JBMR Plus. 2018;2(5):304–307. Kishnani PS et al. Monitoring guidance for patients with hypophosphatasia treated with asfotase alfa. Mol Genet Metab. 2017;122:4–17. Bianchi ML, et al. Hypophosphatasia in adolescents and adults: overview of diagnosis and treatment. Osteoperos Int. 2020;31(8):1445–1460. Genest F, et al. Physical Function and Health-Related Quality of Life in Adults Treated With Asfotase Alfa for Pediatric-Onset Hypophosphatasia. JBMR Plus. 2020;4(9):e10395. Seefried L, et al. Burden of Illness in Adults With Hypophosphatasia: Data From the Global Hypophosphatasia Patient Registry. J Bone Miner Res. 2020;35(11):2171–2178. Strandbech OS, et al. Excellent response to asfotase alfa treatment in an adolescent patient with hypophosphatasia. JIMD Rep. 2021;59(1):10–15. Supplement to: Whyte MP, et al. Asfotase alfa therapy for children with hypophosphatasia. JCI Insight. 2016;1(9):e85971.