Asfotase Alfa: Uses, Side Effects, Dosage - Drugvu

ℹ️ Compiled from public regulatory records · Last regulator revision: May 15, 2026🚩 Report this page

Asfotase Alfa

Enzymes

Sold as STRENSIQ

CA Health CanadaGB MHRAEU EMA

Drug class: Enzymes
Availability: See label
Routes: Subcutaneous
Markets covered: 3
Products on record: 8

Overview

Asfotase Alfa is an active pharmaceutical ingredient in the Enzymes group (A16AB). The information below is compiled per regulator from the product labels on record, with direct links to the original documents.

Regulatory status by market

Market	Regulator	Products	Last revision
CA Canada	Health Canada	5	July 14, 2025
GB United Kingdom	MHRA	2	May 15, 2026
EU European Union	EMA	1	March 18, 2026

CACanada· Health Canada

5 products

Uses

CAOfficial regulatory label· revised July 14, 2025[1]

Strensiq® (asfotase alfa) is indicated for:  Enzyme replacement therapy for patients with confirmed diagnosis of pediatric-onset hypophopatasia (HPP) Treatment with Strensiq should be initiated by a physician with experience in the management of patients with metabolic bone disorders.
1 Pediatrics Pediatrics (0-18 years of age): Based on the data submitted and reviewed by Health Canada, the safety and efficacy of Strensiq in pediatric patients has been established; therefore, Health Canada has authorized an indication for pediatric use (see Section 14 Clinical Trials).
2 Geriatrics Geriatrics (>65 years of age): No data are available to Health Canada; therefore, Health Canada has not authorized an indication for geriatric use.

GBUnited Kingdom· MHRA

2 products

Uses

GBOfficial regulatory label· revised May 15, 2026[2]

1).

How to take

GBOfficial regulatory label· revised May 15, 2026

EUEuropean Union· EMA

1 product

Uses

EUOfficial regulatory label· revised March 18, 2026[3]

1).

How to take

EUOfficial regulatory label· revised March 18, 2026

Sources & citations

[1]Health Canada (DPD) · 02444607 · revised July 14, 2025
[2]MHRA (UK) · PLGB311870005 · revised May 15, 2026
[3]European Medicines Agency · EMEA/H/C/003794 · revised March 18, 2026

Information on this page is compiled from public regulatory records. Drugvu is not affiliated with any regulator or pharmaceutical manufacturer. This is not medical advice. Always consult a qualified healthcare professional.

CAOfficial regulatory label· revised July 14, 2025[1]

2 Recommended Dose and Dosage Adjustment The recommended dosage regimen of Strensiq is 2 mg/kg of body weight administered subcutaneously three times per week, or a dosage regimen of 1 mg/kg of body weight administered six times per week.
The maximum volume of subcutaneous injection is 1 mL per injection. 3 Reconstitution Strensiq is a ready to use, human recombinant tissue-nonspecific alkaline phosphatase-Fc-deca- aspartate fusion protein for subcutaneous administration.
Therefore, Strensiq should not be reconstituted. 4 Administration Strensiq should not be administered intravenously or intramuscularly. Strensiq should be administered as subcutaneous injections. The maximum volume of medication per injection should not exceed 1 mL per single injection site.
If more than 1 mL is required, multiple injections may be administered at the same time at different injection sites. Draft_08APR2021 Alexion STRENSIQ® (asfotase alfa) Page 5 of 33 Injection sites should be rotated and carefully monitored for signs of potential reactions including lipodystrophy.
Strensiq should be administered using sterile disposable syringes and injection needles. The syringes should be of small enough volume that the prescribed dose can be withdrawn from the vial with reasonable accuracy.
For administration of Strensiq, please read the following instructions carefully :
Each vial is for single use and should only be punctured once. Strensiq liquid should look clear to slightly yellow and may have a few small translucent or white particles in it. Do not use if the liquid is discoloured or contains any lumps or large particles in it and get a new vial.
Any unused medicinal product or waste material should be disposed of in accordance with local requirements.
How to inject Strensiq:
Wash your hands thoroughly with soap and water. Take the unopened Strensiq vial(s) out of the refrigerator 15 to 30 minutes before injecting to allow the liquid to reach room temperature. Do not warm Strensiq in any other way (for example, do not warm it in a microwave or in hot water).
Upon removal of the vial(s) from refrigeration, Strensiq should be used within 3 hours maximum (see Section 11 Storage, Stability and Disposal). Remove the protective cap from the Strensiq vial. Withdraw the correct dose of Strensiq into the syringe.
The use of two different gauge needles is recommended, a larger bore needle for withdrawal of the medication, and a smaller bore needle for the injection. Strensiq is injected under the skin (subcutaneously) of your stomach-area (abdomen), upper arms, upper legs, or buttocks.
It is important to rotate Strensiq injection sites. Do not administer injections in areas that are reddened, inflamed or swollen. Determine the injection site then, using a 60-70% alcohol-based solution (isopropyl alcohol or ethanol) on a single use or cotton-wool ball, clean the site.
NOTE:
Do not use any areas in which you feel lumps, firm knots, or pain. Draft_08APR2021 Alexion STRENSIQ® (asfotase alfa) Page 6 of 33 Gently pinch the skin of the chosen injection area between your thumb and index finger. Subcutaneously administer the prescribed dose to the injection site.
Holding the syringe like a pencil or a dart, insert the needle into the raised skin so it is at an angle of between 45° and 90° to the skin surface. For patients who have little subcutaneous fat or thin skin, a 45° angle may be preferable.
While continuing to hold the skin, push the syringe plunger to inject the medication slowly and steadily all the way until you can no longer push down on the plunger. Remove the needle, release the skin fold and gently place a piece of cotton wool or gauze over the injection site for a few seconds.
This will help seal the punctured tissue and prevent any leakage. Do not rub the injection site after injection. Place bandage onto the injection site and properly dispose of the needle. 5 Missed Dose In case of a missed dose, resume the regular schedule as soon as possible.
2 Recommended Dose and Dose Adjustment). Draft_08APR2021 Alexion STRENSIQ® (asfotase alfa) Page 7 of 33

This is not medical advice. Consult a qualified healthcare professional.

Side effects & warnings

CAOfficial regulatory label· Adverse reactions· revised July 14, 2025[1]

5 years]). 35 patient years (PYs) of exposure in patients who received weekly doses ≥ 6 mg/kg (N=109/112 patients). Overall, the most common adverse reactions reported were injection site reactions (74%). The majority of injection site reactions resolved within a week.
One patient withdrew from the trial due to injection site hypersensitivity. 2 Clinical Trial Adverse Reactions). 2 Clinical Trial Adverse Reactions Clinical trials are conducted under very specific conditions. The adverse reaction rates observed in the clinical trials; therefore, may not reflect the rates observed in practice and should not be compared to the rates in the clinical trials of another drug.
Adverse reaction information from clinical trials may be useful in identifying and approximating rates of adverse drug reactions in real-world use. ] Tabulated list of adverse reactions Table 2 summarizes the adverse reactions that occurred at a rate of at least 1% in clinical trials following subcutaneous injection of Strensiq.
Table 2:
Adverse Reactions Reported in at Least 1% of HPP Patients Enrolled in Strensiq Clinical Trials MedDRA System Organ Class Adverse Reaction Category or Term Frequency N=112 (n %) General disorders and administration site conditions Injection site Reactions (ISRs)a 83 (74%) Immune system disorders Hypersensitivity reactionsb 22 (20%) Renal and urinary disorders Nephrolithiasis 8 (7%) Metabolism and nutrition Hypocalcemia 8 (7%) Skin and Subcutaneous Tissue Disorders Skin discolouration 5 (4%) aPreferred terms considered as ISRs are presented in section below.
bPreferred terms considered as hypersensitivity reactions are presented in section below .
Description of selected adverse reactions Injection site reactions (ISRs):
ISRs (including injection site atrophy, abscess, erythema, discoloration, pain, pruritus, macule, swelling, contusion, bruising, lipodystrophy (lipoatrophy or lipohypertrophy), induration, reaction, nodule, rash, papule, hematoma, inflammation, urticaria, calcification, warmth, hemorrhage, cellulitis, scar, mass, extravasation, exfoliation and vesicles) are the most common adverse reactions, observed in approximately 74% of the patients in the clinical studies.
Two patients experienced ISRs that led to reductions of their Strensiq dose. The frequency of ISRs was higher in patients with juvenile-onset HPP and in patients who received injections 6 times/week (compared to 3 times/week). Hypersensitivity Hypersensitivity reactions (including irritability, pyrexia, rash, pruritus, chills, erythema, nausea, vomiting, flushing, oral hypoesthesia, hypersensitivity, headache, tachycardia and cough) have been observed in approximately 22/112 (20%) of the patients in the clinical studies.
A few case reports of signs and symptoms associated with anaphylaxis were received where the patient experienced difficulty breathing, choking sensation, periorbital edema and/or dizziness. Draft_08APR2021 Alexion STRENSIQ® (asfotase alfa) Page 14 of 33 Immunogenicity No trends in adverse events based on antibody status were observed in clinical trials.
Some patients confirmed positive for antidrug antibodies experienced injection site reactions (ISRs) and/or hypersensitivity, however there was no consistent trend in the frequency of these reactions over time noted between ADA ever positive and ADA always negative patients.
Data from post-marketing cases suggests that the development of antibodies may affect clinical efficacy (see Section 7 Warnings & Precautions, subsection Immune). 1 Clinical Trial Adverse Reactions – Pediatrics Refer to Table 2 above.
4 Abnormal Laboratory Findings: Hematologic, Clinical Chemistry and Other Quantitative Data Clinical Trial Findings Apart from the laboratory abnormalities included in Section 8 Adverse Reactions, there were no abnormal hematology or clinical chemistry values considered as adverse drug reactions following Strensiq administration.
5 Post-Market Adverse Reactions Cases from the post-approval setting suggest that development of inhibitory antibodies may be associated with a decreased clinical response.

CAOfficial regulatory label· Warnings and precautions· revised July 14, 2025[1]

3% of patients between birth and 5 years of age in a natural history study of untreated infantile-onset hypophosphatasia patients. Craniosynostosis can lead to increased intracranial pressure. Periodic monitoring (including fundoscopy for signs of papilledema) and prompt intervention for increased intracranial pressure is recommended in patients with HPP below 5 years of age.
In asfotase alfa clinical studies, adverse events of craniosynostosis (associated with increase of intracranial pressure) including worsening of pre-existing craniosynostosis and occurrence of Arnold- Chiari malformation, have been reported in hypophosphatasia patients <5 years of age.
There are insufficient data to establish a causal relationship between exposure to Strensiq and progression of craniosynostosis. Ectopic Calcification Patients with HPP are at increased risk for developing ectopic calcifications. Ophthalmology examinations and renal ultrasounds are recommended at baseline and periodically during treatment with Strensiq to monitor for signs and symptoms of ophthalmic and renal ectopic calcifications and for changes in vision or renal function.
Events of ectopic calcification, including ophthalmic (conjunctival and corneal) calcification and nephrocalcinosis, have been reported in the clinical trial experience with Strensiq. There was insufficient information to determine whether or not the reported events were consistent with the disease or due to Strensiq.
No visual changes or changes in renal function were reported resulting from the occurrence of ectopic calcifications. Hypersensitivity Hypersensitivity reactions have been reported in patients treated with Strensiq, including signs and symptoms consistent with anaphylaxis.
Symptoms included difficulty breathing, choking sensation, periorbital edema, and dizziness. The reactions have occurred within minutes after subcutaneous administration of Strensiq and can occur in patients on treatment for more than one year.
Other hypersensitivity reactions included vomiting, nausea, fever, headache, flushing, irritability, chills, erythema, rash, pruritus, and oral hypoesthesia. If a severe hypersensitivity reaction occurs, discontinue Strensiq treatment and initiate appropriate medical treatment.

This is not medical advice. Consult a qualified healthcare professional.

Side effects & warnings

GBOfficial regulatory label· Adverse reactions· revised May 15, 2026[2]

5 years]). The most common adverse reactions observed were injection site reactions (74%). A few case reports of anaphylactoid/hypersensitivity reaction have been received Tabulated list of adverse reactions Adverse reactions with asfotase alfa are listed by system organ class and preferred term using MedDRA frequency convention very common (1/10), common (1/100 to <1/10), uncommon (1/1,000 to <1/100), rare (1/10,000 to <1/1,000), very rare (<1/10,000) and not known (cannot be estimated from the available data).
Within each frequency grouping, adverse reactions are presented in order of decreasing seriousness.
Table 1:
Adverse Reactions Reported in clinical trials in hypophosphatasia patients System Organ Class Frequency category Adverse reaction Infections and infestations Common Injection site cellulitis Blood and lymphatic system disorders Common Increased tendency to bruise Immune system disorders Common Anaphylactoid reactions Hypersensitivity2 Metabolism and nutrition disorders Common Hypocalcaemia Nervous system disorders Very common Headache Vascular disorders Common Hot flush Gastrointestinal disorders Common Hypoaesthesia oral Nausea Skin and subcutaneous Very common Erythema tissue disorders Common Skin discolouration Skin disorder (stretched skin) Very common Pain in extremityMusculoskeletal and connective tissue disorders Common Myalgia Renal and urinary disorders Common Nephrolithiasis Very common Injection site reactions1 Pyrexia Irritability General disorders and administration site conditions Common Chills Very common ContusionInjury, poisoning and procedural complications Common Scar 1- Preferred terms considered as injection site reactions are presented in section below 2- Preferred terms considered as hypersensitivity are presented in the section below Description of selected adverse reactions Injection site reactions Injection site reactions (including injection site atrophy, abscess, erythema, discolouration, pain, pruritus, macule, swelling, contusion, bruising, lipodystrophy (lipoatrophy or lipohypertrophy), induration, reaction, nodule, rash, papule, haematoma, inflammation, urticarial, calcification, warmth, haemorrhage, cellulitis, scar, mass, extravasation, exfoliation and vesicles) are the most common adverse reactions observed in about 74% of the patients in clinical studies.
Most injection site reactions were mild and self-limiting, and the majority (> 99%) were reported as non- serious. In the clinical trial setting, the majority of patients who experienced an injection site reaction had the first occurrence within the first 12 weeks of treatment with asfotase alfa, and some patients continued to experience injection site reactions until 1 or more years after initiating asfotase alfa dosing.
One patient withdrew from the trial due to injection site hypersensitivity. 4). A few case reports of anaphylactoid/hypersensitivity reaction have also been received and were associated with signs and symptoms of difficulty breathing, choking sensation, periorbital edema and dizziness.
Immunogenicity There is potential for immunogenicity. 0%) tested positive for anti-drug antibodies at some time point after starting Strensiq treatment. 7%) also showed the presence of neutralizing antibodies at some time point post-baseline.
The antibody response (with or without presence of neutralizing antibodies) was time variant in nature. 2). Data from post-marketing cases suggests that the development of antibodies may affect clinical efficacy. No trends in adverse events based on antibody status were observed in clinical trials.
Some patients confirmed positive for antidrug antibodies experienced injection site reactions (ISRs) and/or hypersensitivity, however there was no consistent trend in the frequency of these reactions over time noted between ADA ever positive and ADA always negative patients.
Reporting of suspected adverse reactions Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store.
com, Freephone (UK): 0800321 3902.

GBOfficial regulatory label· Warnings and precautions· revised May 15, 2026[2]

Traceability In order to improve the traceability of biological medicinal products, the name and the batch number of the administered product should be clearly recorded. 8). These symptoms included difficulty breathing, choking sensation, periorbital edema, and dizziness.
The reactions have occurred within minutes after subcutaneous administration of asfotase alfa and can occur in patients on treatment for more than 1 year. Other hypersensitivity reactions included vomiting, nausea, fever, headache, flushing, irritability, chills, skin erythema, rash, pruritus, and oral hypoaesthesia.
If these reactions occur, immediate discontinuation of treatment is recommended and appropriate medical treatment should be initiated. The current medical standards for emergency treatment should be observed. Consider the risks and benefits of re-administering asfotase alfa to individual patients following a severe reaction, taking other factors into account that may contribute to the risk of a hypersensitivity reaction, such as concurrent infection and/ or use of antibiotics.
If the decision is made to re-administer the product, the re-challenge should be made under medical supervision and consideration may be given to use of appropriate pre-medication. Patients should be monitored for recurrence of signs and symptoms of a severe hypersensitivity reaction.
The need for supervision for subsequent administrations and need for emergency treatment for home care should be at the discretion of the treating physician. 3). 8). Rotation of injection sites may help to minimize these reactions. Strensiq administration should be interrupted in any patient experiencing severe injection reactions and appropriate medical therapy administered.
8). 2). Craniosynostosis In asfotase alfa clinical studies adverse events of craniosynostosis (associated with increased intracranial pressure), including worsening of pre-existing craniosynostosis and occurrence of Arnold-Chiari malformation, have been reported in hypophosphatasia patients < 5 years of age.
There are insufficient data to establish a causal relationship between exposure to Strensiq and progression of craniosynostosis. 3% of patients between birth and 5 years of age in a natural history study of untreated infantile-onset hypophosphatasia patients.

This is not medical advice. Consult a qualified healthcare professional.

Side effects & warnings

EUOfficial regulatory label· Adverse reactions· revised March 18, 2026[3]

5 years]). The most common adverse reactions observed were injection site reactions (74%). A few case reports of anaphylactoid/hypersensitivity reaction have been received. Tabulated list of adverse reactions Adverse reactions with asfotase alfa are listed by system organ class and preferred term using MedDRA frequency convention very common (1/10), common (1/100 to <1/10), uncommon (1/1,000 to <1/100), rare (1/10,000 to <1/1,000), very rare (<1/10,000) and not known (cannot be estimated from the available data).
Within each frequency grouping, adverse reactions are presented in order of decreasing seriousness.
Table 1:
Adverse Reactions Reported in clinical trials in hypophosphatasia patients System Organ Class Frequency category Adverse reaction Infections and infestations Common Injection site cellulitis Blood and lymphatic system disorders Common Increased tendency to bruise Immune system disorders Common Anaphylactoid reactions Hypersensitivity2 Metabolism and nutrition disorders Common Hypocalcaemia Nervous system disorders Very common Headache Vascular disorders Common Hot flush Gastrointestinal disorders Common Hypoaesthesia oral Nausea Skin and subcutaneous tissue disorders Very common Erythema Common Skin discolouration Skin disorder (stretched skin) Musculoskeletal and connective tissue disorders Very common Pain in extremity Common Myalgia Renal and urinary disorders Common Nephrolithiasis General disorders and administration site conditions Very common Injection site reactions1 Pyrexia Irritability Common Chills Injury, poisoning and procedural complications Very common Contusion Common Scar 1- Preferred terms considered as injection site reactions are presented in section below 2- Preferred terms considered as hypersensitivity are presented in the section below 8 Description of selected adverse reactions Injection site reactions Injection site reactions (including injection site atrophy, abscess, erythema, discolouration, pain, pruritus, macule, swelling, contusion, bruising, lipodystrophy (lipoatrophy or lipohypertrophy), induration, reaction, nodule, rash, papule, haematoma, inflammation, urticarial, calcification, warmth, haemorrhage, cellulitis, scar, mass, extravasation, exfoliation and vesicles) are the most common adverse reactions observed in about 74% of the patients in clinical studies.
Most injection site reactions were mild and self-limiting, and the majority (> 99%) were reported as non-serious. In the clinical trial setting, the majority of patients who experienced an injection site reaction had the first occurrence within the first 12 weeks of treatment with asfotase alfa, and some patients continued to experience injection site reactions until 1 or more years after initiating asfotase alfa dosing.
One patient withdrew from the trial due to injection site hypersensitivity. 4). A few case reports of anaphylactoid/hypersensitivity reaction have also been received and were associated with signs and symptoms of difficulty breathing, choking sensation, periorbital edema and dizziness.
Immunogenicity There is potential for immunogenicity. 0%) tested positive for anti- drug antibodies at some time point after starting Strensiq treatment. 7%) also showed the presence of neutralizing antibodies at some time point post-baseline.
The antibody response (with or without presence of neutralizing antibodies) was time variant in nature. 2). Data from post-marketing cases suggests that the development of antibodies may affect clinical efficacy. No trends in adverse events based on antibody status were observed in clinical trials.
Some patients confirmed positive for antidrug antibodies experienced injection site reactions (ISRs) and/or hypersensitivity, however there was no consistent trend in the frequency of these reactions over time noted between ADA ever positive and ADA always negative patients.
Reporting of suspected adverse reactions Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the national reporting system listed in Appendix V.

EUOfficial regulatory label· Warnings and precautions· revised March 18, 2026[3]

Traceability In order to improve the traceability of biological medicinal products, the name and the batch number of the administered product should be clearly recorded. 8). These symptoms included difficulty breathing, choking sensation, periorbital edema, and dizziness.
The reactions have occurred within minutes after subcutaneous administration of asfotase alfa and can occur in patients on treatment for more than 1 year. Other hypersensitivity reactions included vomiting, nausea, fever, headache, flushing, irritability, chills, skin erythema, rash, pruritus, and oral hypoaesthesia.
If these reactions 5 occur, immediate discontinuation of treatment is recommended and appropriate medical treatment should be initiated. The current medical standards for emergency treatment should be observed. Consider the risks and benefits of re-administering asfotase alfa to individual patients following a severe reaction, taking other factors into account that may contribute to the risk of a hypersensitivity reaction, such as concurrent infection and/ or use of antibiotics.
If the decision is made to re- administer the product, the re-challenge should be made under medical supervision and consideration may be given to use of appropriate pre-medication. Patients should be monitored for recurrence of signs and symptoms of a severe hypersensitivity reaction.
The need for supervision for subsequent administrations and need for emergency treatment for home care should be at the discretion of the treating physician. 3). 8). Rotation of injection sites may help to minimize these reactions. Strensiq administration should be interrupted in any patient experiencing severe injection reactions and appropriate medical therapy administered.
8). 2). Craniosynostosis In asfotase alfa clinical studies adverse events of craniosynostosis (associated with increased intracranial pressure), including worsening of pre-existing craniosynostosis and occurrence of Arnold- Chiari malformation, have been reported in hypophosphatasia patients < 5 years of age.
There are insufficient data to establish a causal relationship between exposure to Strensiq and progression of craniosynostosis. 3% of patients between birth and 5 years of age in a natural history study of untreated infantile-onset hypophosphatasia patients.

This is not medical advice. Consult a qualified healthcare professional.