STRENSIQ ASFOTASE ALFA 28 mg/.7mL Solution, 12 vials
🆔 Identity & classification
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🏷️ RxNorm drug class
This medicine belongs to the Tissue-nonspecific Alkaline Phosphatase class.
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🏭 Manufacturer & labeler
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🩺 Clinical
- Hypophosphatasia (HPP) is a rare genetic disorder where the body doesn't make enough of an enzyme called TNSALP. Without that enzyme, bones can't harden properly, which causes prob...
- What exactly is hypophosphatasia and why does my child need this medication?
- Strensiq is injected under the skin — not given as a pill or IV. Most patients inject it either three or six times per week, depending on what your prescriber decides works best. Y...
- How often does Strensiq need to be injected, and where on the body?
Patient education
Supplement & herbal interactions
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Ask a licensed pharmacist directly — free, answered by our team.
🧪 Inactive Ingredients / Excipients
Inactive ingredients, also called excipients, are components of the drug product other than the active ingredient. They may include fillers, dyes, coatings, preservatives, flavors, or other formulation ingredients.
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6.13 mg / 0.7 mL
UNII 451W47IQ8X
Sodium chloride is common table salt. It's used in medicines as a buffer to maintain proper pH, as a filler to add bulk, or to adjust the osmotic balance in liquid formulations.
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3.85 mg / 0.7 mL
UNII 70WT22SF4B
A mineral salt that acts as a buffer to maintain the pH balance of the medication. It helps stabilize the drug's potency and prevents unwanted chemical changes during storage.
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0.43 mg / 0.7 mL
UNII 593YOG76RN
A salt made from sodium and phosphate that helps regulate acidity and maintain proper pH balance in the medicine. It also acts as a buffer to keep the product stable.
3 inactive ingredients listed in the exact product block matched to this NDC.
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ingredient classCode="IACT" elements from the exact product block matched by this NDC. Label-section narrative from DailyMed / the openFDA label index is shown separately when available.Inactive ingredient FAQ
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💲 Pricing
A drug doesn't have one price. Each row is a different public payment system, and none is what you'd pay at the counter — that depends on your insurance. The ⓘ on each row explains what it measures.
| Price system | Per mL | Per package |
|---|---|---|
| Retail pharmacies payNADAC · weekly | Not in the retail survey — common for institutional, discontinued, or low-volume packs. | |
| Medicaid paysCMS SDUD · 12 mo | $2,847.56 | $23,919.53 / 8.4 ml |
| Medicare drug plans payPart D · quarterly | No Part D plan price is available for this NDC in our data. | |
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🔁 Therapeutic equivalents
| Product | Labeler | Pack | NADAC/unit | TE | Status | Price vs. this |
|---|---|---|---|---|---|---|
| Strensiq 28 mg/.7mLthis 25682-0013-12 | Alexion | 12 vials | — | — | FDA listed | — |
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⏳ Availability & biosimilar status
Biologics have no small-molecule generics; biosimilar competition is tracked in the FDA Purple Book.
Why the date isn’t exact: Biosimilar timing can change because patents may be challenged, settled, licensed, added or removed, and litigation can move the real date earlier or later.
🛈 What do these terms mean?
- Biologic patent
- A patent the reference product’s maker has publicly listed. A biosimilar generally can’t launch until these expire — unless they’re invalidated or resolved in a settlement.
- Reference-product exclusivity
- A flat 12 years of FDA market protection from the biologic’s first licensure (the BPCIA). No biosimilar can be licensed before it ends, regardless of patents.
- Interchangeable exclusivity
- The first interchangeable biosimilar can earn a period as the only interchangeable version (pharmacists can substitute it without the prescriber).
- Earliest biosimilar (LOE)
- The latest of all the dates above — the soonest a biosimilar can realistically reach the market. Litigation and settlements can move it earlier.
Biologics have no small-molecule “generics” — competition comes from FDA-licensed biosimilars, tracked in the FDA Purple Book.
| Code | What it grants | Expires |
|---|---|---|
| RefProduct | Reference-product exclusivity (12-year, BPCIA) — no biosimilar can be licensed before this date | Oct 23, 2027 |
Is there a biosimilar for STRENSIQ 28 MG/0.7 ML VIAL?
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🗺️ Medicaid utilization & spend
📊 Medicare Part D spend CMS · PART D · 2026 (Q1)
🔬 Reported adverse events (FAERS)
Top reported reactions
Age at onset
Reporter sex
Serious outcomes
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📦 Packaging — all sizes for this product
| Package NDC | Description | Marketing start | Status |
|---|---|---|---|
| 25682-0013-12 You're viewing this | 12 VIAL in 1 CARTON (25682-013-12) / .7 mL in 1 VIAL (25682-013-01) | 2015-10-23 | Active |
🧭 About this NDC listing & data coverage
What data is (and isn’t) available for this NDC — tap to expand
| NDC identity (package / product / labeler codes) | ✓ Available |
| Labeler | ✓ Available |
| Product & package description | ✓ Available |
| Marketing category & status | ✓ Available |
| Active ingredient / dosage form / route | ✓ Available |
| FDA label (SPL via DailyMed) | ✓ Available |
| Package photos | ✓ Available |
| Inactive ingredients (structured) | ✓ Available |
| NADAC pharmacy acquisition price (CMS) | — Not published for this NDC CMS publishes NADAC only for NDCs reported in its retail-pharmacy survey. |
| Orange Book / therapeutic-equivalence data | ✓ Available |
| HCPCS J-code billing crosswalk | — Not published for this NDC Most self-administered / retail products have no J-code — that is normal. |
| Medicaid utilization (CMS SDUD) | ✓ Available |
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📄 Full prescribing information FDA SPL
🚨 Boxed Warning ▾
WARNING: HYPERSENSITIVITY REACTIONS INCLUDING ANAPHYLAXIS Patients treated with enzyme replacement therapies have experienced life-threatening hypersensitivity reactions, including anaphylaxis. Anaphylaxis has occurred during the early course of enzyme replacement therapy and after extended duration of therapy. Initiate STRENSIQ under the supervision of a healthcare provider with appropriate medical monitoring and support measures.
If a severe hypersensitivity reaction (e.g., anaphylaxis) occurs, discontinue STRENSIQ and immediately initiate appropriate medical treatment, including use of epinephrine. Inform patients of the symptoms of life-threatening hypersensitivity reactions, including anaphylaxis and to seek immediate medical care should symptoms occur [see Warnings and Precautions (5.1) ] . WARNING: HYPERSENSITIVITY REACTIONS INCLUDING ANAPHYLAXIS See full prescribing information for complete boxed warning.
Anaphylaxis has occurred during the early course of enzyme replacement therapy and after extended duration of therapy. ( 5.1 ) Initiate STRENSIQ under the supervision of a healthcare provider with appropriate medical monitoring and support measures. ( 5.1 ) If a severe hypersensitivity reaction (e.g., anaphylaxis) occurs, discontinue STRENSIQ and immediately initiate appropriate medical treatment, including use of epinephrine.
( 5.1 )
🎯 Indications and Usage ▾
1 INDICATIONS AND USAGE STRENSIQ ® is indicated for the treatment of patients with perinatal/infantile- and juvenile-onset hypophosphatasia (HPP). STRENSIQ is a tissue nonspecific alkaline phosphatase indicated for the treatment of patients with perinatal/infantile- and juvenile-onset hypophosphatasia (HPP). ( 1 )
⏱️ Dosage and Administration ▾
2 DOSAGE AND ADMINISTRATION Perinatal/Infantile-Onset HPP ( 2.2 ) Recommended dosage regimen is 2 mg/kg administered subcutaneously three times per week, or 1 mg/kg administered six times per week. Injection site reactions may limit the tolerability of the six times per week regimen. The dose may be increased to 3 mg/kg three times per week for insufficient efficacy.
Juvenile-Onset HPP ( 2.3 ) Recommended dosage regimen is 2 mg/kg administered subcutaneously three times per week, or 1 mg/kg administered six times per week. Injection site reactions may limit the tolerability of the six times per week regimen. Preparation and Weight-Based Dosing ( 2.4 ): Caution: Do not use the 80 mg/0.8 mL vial in pediatric patients weighing less than 40 kg because the systemic asfotase alfa exposure achieved with the 80 mg/0.8 mL vial (higher concentration) is lower than that achieved with the other strength vials (lower concentration).
A lower exposure may not be adequate for this subgroup of patients. See full prescribing information for tables of weight-based dosing by treatment regimen. Administration ( 2.5 ): For subcutaneous injection only.
Rotate injection sites. Do not administer to areas that are reddened, inflamed or swollen.
2.1Recommendations Prior to STRENSIQ Treatment Initiate STRENSIQ under the supervision of a healthcare provider with appropriate medical monitoring and support measures [see Warnings and Precautions (5.1) ].
2.2Dosage for Perinatal/Infantile-Onset HPP The recommended dosage regimen of STRENSIQ for the treatment of perinatal/infantile-onset HPP is 6 mg/kg per week administered subcutaneously as either: 2 mg/kg three times per week, or 1 mg/kg six times per week. Injection site reactions may limit the tolerability of the six times per week regimen [see Adverse Reactions (6.1) ]. The dose of STRENSIQ may be increased for lack of efficacy (e.g., no improvement in respiratory status, growth, or radiographic findings) up to 9 mg/kg per week administered subcutaneously as 3 mg/kg three times per week.
2.3Dosage for Juvenile-Onset HPP The recommended dosage regimen of STRENSIQ for the treatment of juvenile-onset HPP is 6 mg/kg per week administered subcutaneously as either: 2 mg/kg three times per week, or 1 mg/kg six times per week. Injection site reactions may limit the tolerability of the six times per week regimen [see Adverse Reactions (6.1) ].
2.4Preparation and Weight-Based Dosing Tables Caution: Do not use the 80 mg/0.8 mL vial of STRENSIQ in pediatric patients weighing less than 40 kg because the systemic exposure of asfotase alfa achieved with the 80 mg/0.8 mL vial (higher concentration) is lower than that achieved with the other strength vials (lower concentration). A lower exposure may not be adequate for this subgroup of patients [see Dosage Forms and Strengths (3) , Clinical Pharmacology (12.3) ] . 1.
Determine the total weekly volume needed for the prescribed dosage based on the patient's weight and recommended dosage. Follow these steps to determine the patient dose. Total weekly dose (mg) = patient's weight (kg) × prescribed dose (mg/kg/week) Total injection volume (mL) per week = Total dose (mg/week) divided by the STRENSIQ concentration (40 mg/mL or 100 mg/mL).
Note product concentrations are: 40 mg/mL (vial strengths 18 mg/0.45 mL, 28 mg/0.7 mL, 40 mg/mL) or 100 mg/mL (vial strength 80 mg/0.8 mL). Round total injection volume to the nearest hundredth of a mL Total number of vials per week = Total injection volume divided by vial volume (mL) 2. Determine the number of injection days per week (three or six per week).
3. Determine dose per injection day. Patient weights should be rounded to the nearest kilogram when determining dose.
Use the following tables for guidance, for patients administering 2 mg/kg three times per week (Table 1), 1 mg/kg six times per week (Table 2) and for dose escalations to 3 mg/kg three times per week, recommended only for patients with perinatal/infantile-onset HPP [see…
💊 Dosage Forms and Strengths ▾
3 DOSAGE FORMS AND STRENGTHS STRENSIQ is a clear, slightly opalescent or opalescent, colorless to slightly yellow aqueous solution; few small translucent or white particles may be present. The product is available as: Injection: 18 mg/0.45 mL, 28 mg/0.7 mL, 40 mg/mL, or 80 mg/0.8 mL solution in single-dose vials Injection: 18 mg/0.45 mL, 28 mg/0.7 mL, 40 mg/mL, or 80 mg/0.8 mL solution in single-dose vials. ( 3 )
⛔ Contraindications ▾
4 CONTRAINDICATIONS None. None. ( 4 )
⚠️ Warnings and Cautions ▾
5 WARNINGS AND PRECAUTIONS Lipodystrophy: Localized reactions were reported after several months of treatment; follow proper injection technique and rotate injection sites. ( 5.2 ) Ectopic Calcifications (eye and kidneys): Monitor using ophthalmologic examinations and renal ultrasounds at baseline and periodically during treatment. ( 5.3 ) Possible Immune-Mediated Clinical Effects: Evaluate patients for antibody formation if clinically indicated. ( 5.4 )
5.1Hypersensitivity Reactions Including Anaphylaxis Life-threatening hypersensitivity reactions, including anaphylaxis, have been reported in patients treated with enzyme replacement therapies, including STRENSIQ. Signs and symptoms consistent with anaphylaxis included difficulty breathing, choking sensation, nausea, periorbital edema, and dizziness. These reactions have occurred within minutes after subcutaneous administration of STRENSIQ and have been observed more than 1 year after treatment initiation.
Other hypersensitivity reactions have also been reported in STRENSIQ-treated patients, including vomiting, fever, headache, flushing, irritability, chills, erythema, rash, pruritus and oral hypoesthesia [see Adverse Reactions (6.1) ] . Anaphylaxis has occurred during the early course of enzyme replacement therapy and after extended duration of therapy. Initiate STRENSIQ under the supervision of a healthcare provider with appropriate medical monitoring and support measures.
If a severe hypersensitivity reaction (e.g., anaphylaxis) occurs, discontinue STRENSIQ and immediately initiate appropriate medical treatment, including use of epinephrine. Consider the risks and benefits of re-administering STRENSIQ to individual patients following a severe reaction. If the decision is made to re-administer the product, monitor patients for a reoccurrence of signs and symptoms of a severe hypersensitivity reaction.
Inform patients of the symptoms of life-threatening hypersensitivity reactions, including anaphylaxis and to seek immediate medical care should symptoms occur.
5.2Lipodystrophy Localized lipodystrophy, including lipoatrophy and lipohypertrophy, has been reported at injection sites after several months in patients treated with STRENSIQ in clinical trials [see Adverse Reactions (6.1) ] . Advise patients to follow proper injection technique and to rotate injection sites [see Dosage and Administration (2.5) ] .
5.3Ectopic Calcifications Patients with HPP are at increased risk for developing ectopic calcifications. Events of ectopic calcification, including ophthalmic (conjunctival and corneal) and renal (nephrocalcinosis, nephrolithiasis), 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. 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.
5.4Possible Immune-Mediated Clinical Effects In clinical trials, most STRENSIQ-treated patients developed anti-asfotase alfa antibodies and neutralizing antibodies which resulted in reduced systemic exposure of asfotase alfa [see Immunogenicity (6.2) ]. In postmarketing reports, some STRENSIQ-treated patients with initial therapeutic response subsequently developed recurrence and worsening in disease-associated laboratory and radiographic biomarkers (some in association with neutralizing antibodies) suggesting possible immune-mediated effects on STRENSIQ's pharmacologic action resulting in disease progression [see Adverse Reactions (6.3) ] .
The effect of anti-asfotase alfa antibody formation on the long-term efficacy of STRENSIQ is unknown. There are no marketed anti-asfotase alfa…
🤒 Adverse Reactions ▾
6 ADVERSE REACTIONS The following adverse reactions are described below and elsewhere in the labeling: Hypersensitivity Reactions [see Warnings and Precautions (5.1) ] Lipodystrophy [see Warnings and Precautions (5.2) ] Ectopic Calcifications [see Warnings and Precautions (5.3) ] Possible Immune-Mediated Clinical Effects [see Warnings and Precautions (5.4) ] Most common adverse reactions (≥ 10%) are injection site reactions, lipodystrophy, ectopic calcifications and hypersensitivity reactions. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Alexion Pharmaceuticals, Inc. at 1-844-259-6783 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.
6.1Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The data described below reflect exposure to STRENSIQ in 99 patients with perinatal/infantile- or juvenile onset HPP (age 1 day to 58 years) treated with STRENSIQ, most for more than 2 years (range 1 day to 312 weeks [78 months]): 51 patients received at least 96 weeks (24 months) of treatment and 39 patients received 168 weeks (42 months) or more of treatment [see Clinical Studies (14) ] .
Common Adverse Reactions Overall, the most common adverse reactions reported were injection site reactions (63%) . Other common adverse reactions included lipodystrophy (28%), ectopic calcifications (14%), and hypersensitivity reactions (12%). Table 4 summarizes the adverse reactions that occurred at a rate of at least 10% in clinical trials following subcutaneous injection of STRENSIQ by patient population and STRENSIQ dosage regimen.
The frequency of injection site reactions, lipodystrophy and ectopic calcification were higher in patients with juvenile-onset HPP as compared to perinatal/infantile-onset HPP patients. The majority of injection site reactions resolved within a week. Two patients experienced injection site reactions that led to reductions of their STRENSIQ dose.
One patient switched from six times per week dosing to 3 times per week dosing as a result of injection site reactions. One other patient experienced a severe injection site reaction of injection site discoloration and withdrew from the trial. Table 4: Adverse Reactions Reported in at Least 10% of Patients with Perinatal/Infantile- or Juvenile-onset HPP Enrolled in STRENSIQ Clinical Trials Perinatal/Infantile-onset HPP Juvenile-onset HPP Adverse Reaction Category or Term STRENSIQ less than or equal to 6 mg/kg per week (N=66) n (%) STRENSIQ more than 6 mg/kg/week Adverse reactions are from the combined period of 6 mg/kg and above (i.e. total drug exposure regardless of starting dose and intermediary doses as long as the patient reached doses > 6 mg/kg) (N=13) n (%) Total (N=79) n (%) STRENSIQ (N=20) n (%) Injection site reactions 38 (58) 6 (46) 44 (56) 18 (90) Erythema 29 (44) 3 (23) 32 (41) 15 (75) Discoloration/ Hypopigmentation 11 (17) 1 (8) 12 (15) 8 (40) Pain/ Tenderness 10 (15) 1 (8) 11 (14) 8 (40) Pruritus/ Itching 10 (15) 0 (0) 10 (13) 7 (35) Swelling 8 (12) 0 (0) 8 (10) 6 (30) Induration 9 (14) 1 (8) 10 (13) 3 (15) Macule 4 (6) 0 (0) 4 (5) 7 (35) Reaction, not otherwise specified 6 (9) 1 (8) 7 (9) 4 (20) Bruising 6 (9) 0 (0) 6 (8) 4 (20) Nodule 2 (3) 0 (0) 2 (3) 2 (10) Other injection site reactions Other injection site reactions include injection site rash, inflammation, papule, hemorrhage, hematoma, urticaria, warmth, calcification, mass, scar and cellulitis.
10 (15) 3 (23) 13 (17) 4 (20) Ectopic calcifications 3 (5) 0 (0) 3 (4) 11 (55) Lipodystrophy 12 (18) 2 (15) 14 (18) 14 (70) Injection site atrophy 4 (6) 2 (15) 6 (8) 8 (40) Injection site hypertrophy 5 (8) 0 (0) 5 (6) 6 (30) Other lipodystrophy Other lipodystrophy includes lipohypertrophy. 4 (6) 0 (0) 4 (5) 1 (5) Hypersensitivity reactions 7 (11) 3 (23) 10 (13) 2 (10) Vomiti…
🔄 Drug Interactions ▾
7 DRUG INTERACTIONS Drug Interference with Laboratory Tests: Alkaline Phosphatase (ALP) is used as a detection reagent in many laboratory tests and the presence of asfotase alfa in clinical laboratory samples could result in erroneous test results. Inform laboratory personnel and discuss use of an alternative testing platform for patients on treatment. ( 7.1 ) Serum Alkaline Phosphatase : Serum ALP measurements are expected to be elevated during treatment and may be unreliable for clinical decision making.
( 7.1 )
7.1Drug Interference with Laboratory Tests Laboratory Tests Utilizing Alkaline Phosphatase as a Detection Reagent Studies have shown that there is analytical interference between asfotase alfa and laboratory tests that utilize an alkaline phosphatase (ALP)-conjugated test system, rendering erroneous test results in patients treated with STRENSIQ. ALP-conjugated test systems are utilized to measure substances such as hormones, bacterial antigens and antibodies. Therefore, it is recommended that laboratory assays which do not have ALP-conjugate technology be used when testing samples from patients who are receiving STRENSIQ.
To avoid erroneous test results for patients treated with STRENSIQ, inform laboratory personnel that the patient is being treated with STRENSIQ and discuss the use of a testing platform which does not utilize an ALP-conjugated test system. Serum Alkaline Phosphatase High serum ALP measurements detected through clinical laboratory testing are expected in patients receiving STRENSIQ and reflect circulating concentrations of asfotase alfa . Do not rely on serum ALP measurements for clinical decision making in patients treated with STRENSIQ.
👥 Use in Specific Populations ▾
8 USE IN SPECIFIC POPULATIONS
8.1Pregnancy Risk Summary There are no available data on STRENSIQ use in pregnant women to inform a drug associated risk. In animal reproduction studies, asfotase alfa administered intravenously to pregnant rats and rabbits during the period of organogenesis showed no evidence of fetotoxicity, embryolethality or teratogenicity at doses causing plasma exposures up to 21 and 24 times, respectively, the exposure at the recommended human dose (see Data ) . In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively.
Data Animal Data Asfotase alfa administered during the period of organogenesis to rats (from gestation Day 6 to Day 19 post-partum) and rabbits (on gestation days 7 to 19) at intravenous doses up to 50 mg/kg/day, approximately 21 and 24 times the human AUC of 65486 ng.h/mL at 2 mg/kg dose administered three times weekly for a 50 kg individual, respectively did not cause any adverse effects on embryofetal development. A pre- and post-natal development study in pregnant rats showed no evidence of adverse effects on pre- and post-natal development at intravenous doses (from Day 6 of gestation to Day 19 postpartum) of asfotase alfa up to 50 mg/kg/day approximately 21 times the human AUC of 65486 ng.h/mL at 2 mg/kg dose administered three times weekly for a 50 kg individual.
8.2Lactation Risk Summary There are no data on the presence of asfotase alfa in human milk, the effects on the breastfed infant, or the effects on milk production. The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for STRENSIQ and any potential adverse effects on the breastfed infant from asfotase alfa or from the underlying maternal condition.
8.4Pediatric Use The safety and effectiveness of STRENSIQ for the treatment of perinatal/infantile- and juvenile-onset HPP have been established in pediatric patients. Use of STRENSIQ for this indication is based on 4 prospective, open-label clinical trials conducted in 89 pediatric patients with perinatal/infantile-onset or juvenile-onset HPP [see Clinical Studies (14) ].
8.5Geriatric Use No patients with perinatal/infantile- or juvenile-onset HPP aged 65 years were enrolled in clinical trials of STRENSIQ. Therefore, there is no information available to determine whether patients aged 65 years and over respond differently from younger patients.
🤰 Pregnancy ▾
8.1Pregnancy Risk Summary There are no available data on STRENSIQ use in pregnant women to inform a drug associated risk. In animal reproduction studies, asfotase alfa administered intravenously to pregnant rats and rabbits during the period of organogenesis showed no evidence of fetotoxicity, embryolethality or teratogenicity at doses causing plasma exposures up to 21 and 24 times, respectively, the exposure at the recommended human dose (see Data ) . In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively.
Data Animal Data Asfotase alfa administered during the period of organogenesis to rats (from gestation Day 6 to Day 19 post-partum) and rabbits (on gestation days 7 to 19) at intravenous doses up to 50 mg/kg/day, approximately 21 and 24 times the human AUC of 65486 ng.h/mL at 2 mg/kg dose administered three times weekly for a 50 kg individual, respectively did not cause any adverse effects on embryofetal development. A pre- and post-natal development study in pregnant rats showed no evidence of adverse effects on pre- and post-natal development at intravenous doses (from Day 6 of gestation to Day 19 postpartum) of asfotase alfa up to 50 mg/kg/day approximately 21 times the human AUC of 65486 ng.h/mL at 2 mg/kg dose administered three times weekly for a 50 kg individual.
🧒 Pediatric Use ▾
8.4Pediatric Use The safety and effectiveness of STRENSIQ for the treatment of perinatal/infantile- and juvenile-onset HPP have been established in pediatric patients. Use of STRENSIQ for this indication is based on 4 prospective, open-label clinical trials conducted in 89 pediatric patients with perinatal/infantile-onset or juvenile-onset HPP [see Clinical Studies (14) ].
🧓 Geriatric Use ▾
8.5Geriatric Use No patients with perinatal/infantile- or juvenile-onset HPP aged 65 years were enrolled in clinical trials of STRENSIQ. Therefore, there is no information available to determine whether patients aged 65 years and over respond differently from younger patients.
🧬 Clinical Pharmacology ▾
12 CLINICAL PHARMACOLOGY
12.1Mechanism of Action HPP is caused by a deficiency in TNSALP enzyme activity, which leads to elevations in several TNSALP substrates, including inorganic pyrophosphate (PPi). TNSALP is a metallo-enzyme that catalyzes the hydrolysis of phosphomonoesters with release of inorganic phosphate and alcohol. Elevated extracellular levels of PPi block hydroxyapatite crystal growth which inhibits bone mineralization and causes an accumulation of unmineralized bone matrix which manifests as rickets and bone deformation in infants and children and as osteomalacia (softening of bones) once growth plates close, along with muscle weakness.
Replacement of the TNSALP enzyme upon STRENSIQ treatment reduces the enzyme substrate levels.
12.2Pharmacodynamics Perinatal/infantile- and juvenile-onset HPP patients treated with STRENSIQ had reductions in plasma TNSALP substrates, PPi and pyridoxal 5'-phosphate (PLP) within 6 to 12 weeks of treatment. Reductions in plasma PPi and PLP levels did not correlate with clinical outcomes. Bone biopsy data from perinatal/infantile-onset and juvenile-onset HPP patients treated with STRENSIQ demonstrated decreases in osteoid volume and thickness indicating improved bone mineralization.
12.3Pharmacokinetics Based on data in 38 HPP patients, the pharmacokinetics of asfotase alfa exhibit dose proportionality across the dose range of 0.3 mg/kg to 3 mg/kg once every other day (three times a week) and appear to be time-independent. Steady state exposure was achieved as early as three weeks after the administration of the first dose. The elimination half-life following subcutaneous administration was approximately 5 days.
Table 6 summarizes the pharmacokinetic parameters following multiple doses in 20 HPP patients after subcutaneous administration of STRENSIQ at 2 mg/kg three times per week in Study 2 (age of less than or equal to 5 years) and Study 3 (age of greater than 5 to 12 years), indicating the pharmacokinetics were similar between patients in the two age groups. Table 6: Summary of Pharmacokinetic Parameters Following Multiple Subcutaneous Administration of STRENSIQ 2 mg/kg Three Times per Week Study 2 Study 3 Data are presented as mean ± standard deviation (range).
Study 3 includes patients with perinatal/infantile- or juvenile-onset of disease. t last , time of last concentration; t max , time of maximal concentration; C max , maximal concentration; AUC t , area under the concentration-time curves over a dosing interval of 48 hours N 14 6 Age (year) 3.4 ± 2.1 (0.2, 6.2) 8.6 ± 2.2 (6.1, 12.6) Weight at baseline (kg) 11.2 ± 5.0 (2.9, 17.1) 21.2 ± 7.9 (11.4, 35.4) t last (h) 48.1 ± 0.1 (47.9, 48.3) 48.0 ± 0.1 (48.0, 48.1) t max (h) 14.9 ± 10.4 (0, 32.2) 20.8 ± 10.0 (11.9, 32.2) C max (ng/mL) 1794 ± 690 (856, 3510) 2108 ± 788 (905, 3390) AUC t (h*ng/mL) 66042 ± 25758 (27770, 119122) 89877 ± 33248 (37364, 142265) Accumulation Ratio Ratio values reflect the fold increase of AUC t from Week 1 based on mean AUC t, values.
1.5
3.9Population PK analysis of asfotase alfa concentrations supports weight-based dosing because body weight is a major covariate of asfotase alfa clearance. The formulation concentration had an impact on the systemic exposure of asfotase alfa in HPP patients. The higher concentration formulation (80 mg/0.8 mL vial) achieved an approximately 25% lower systemic asfotase alfa exposure (i.e., concentrations and AUC) compared to the lower concentration formulations (18 mg/0.45 mL, 28 mg/0.7 mL or 40 mg/mL vials) at the same dose of STRENSIQ [see Dosage and Administration (2.2) ] .
Anti-Drug Antibody Effects on Pharmacokinetics Formation of anti-drug antibodies resulted in reduced systemic exposure of asfotase alfa.
🧬 Mechanism of Action ▾
12.1Mechanism of Action HPP is caused by a deficiency in TNSALP enzyme activity, which leads to elevations in several TNSALP substrates, including inorganic pyrophosphate (PPi). TNSALP is a metallo-enzyme that catalyzes the hydrolysis of phosphomonoesters with release of inorganic phosphate and alcohol. Elevated extracellular levels of PPi block hydroxyapatite crystal growth which inhibits bone mineralization and causes an accumulation of unmineralized bone matrix which manifests as rickets and bone deformation in infants and children and as osteomalacia (softening of bones) once growth plates close, along with muscle weakness.
Replacement of the TNSALP enzyme upon STRENSIQ treatment reduces the enzyme substrate levels.
📦 How Supplied / Storage and Handling ▾
16 HOW SUPPLIED/STORAGE AND HANDLING STRENSIQ is supplied as a sterile, nonpyrogenic, preservative-free, clear, slightly opalescent or opalescent, colorless to slightly yellow aqueous solution; a few small translucent or white particles may be present. The product is available as single-dose vials in a carton of one (1) or twelve (12) vials at the following strengths: Table 10: STRENSIQ Vial Presentations Strength National Drug Code (NDC) Quantity of Vials in Carton 18 mg/0.45 mL NDC 25682-010-01 1 NDC 25682-010-12 12 28 mg/0.7 mL NDC 25682-013-01 1 NDC 25682-013-12 12 40 mg/mL NDC-25682-016-01 1 NDC-25682-016-12 12 For pediatric patients 40 kg and greater 80 mg/0.8 mL NDC 25682-019-01 1 NDC 25682-019-12 12 STRENSIQ vials must be stored in the original carton until the time of use under refrigerated conditions at 2°C to 8°C (36°F to 46°F) and protected from light.
Once removed from refrigeration, STRENSIQ should be administered within 3 hours. Do not use beyond the expiration date stamped on the carton. DO NOT FREEZE OR SHAKE.
Vials are for one time use only. Discard any unused product.
📦 Storage and Handling ▾
STRENSIQ vials must be stored in the original carton until the time of use under refrigerated conditions at 2°C to 8°C (36°F to 46°F) and protected from light. Once removed from refrigeration, STRENSIQ should be administered within 3 hours. Do not use beyond the expiration date stamped on the carton. DO NOT FREEZE OR SHAKE. Vials are for one time use only. Discard any unused product.
📋 Description ▾
11 DESCRIPTION Asfotase alfa is a tissue nonspecific alkaline phosphatase (TNSALP) produced by recombinant DNA technology in a Chinese hamster ovary cell line. Asfotase alfa is a soluble glycoprotein composed of two identical polypeptide chains. Each chain contains 726 amino acids with a theoretical mass of 161 kDa.
Each chain consists of the catalytic domain of human TNSALP, the human immunoglobulin G 1 Fc domain and a deca-aspartate peptide used as a bone targeting domain. The two polypeptide chains are covalently linked by two disulfide bonds. STRENSIQ (asfotase alfa) injection is a sterile, preservative-free, nonpyrogenic, clear, slightly opalescent or opalescent, colorless to slightly yellow, with few small translucent or white particles, aqueous solution for subcutaneous administration.
STRENSIQ is supplied in glass single-dose vials containing asfotase alfa; dibasic sodium phosphate, heptahydrate; monobasic sodium phosphate, monohydrate; and sodium chloride at a pH between 7.2 and 7.6. Table 5 describes the content of STRENSIQ vial presentations. Table 5: Content of STRENSIQ Vial Presentations Ingredient Quantity per Vial Asfotase Alfa 18 mg/0.45 mL 28 mg/0.7 mL 40 mg/mL 80 mg/0.8 mL Dibasic sodium phosphate, heptahydrate 2.48 mg 3.85 mg 5.5 mg 4.4 mg Monobasic sodium phosphate, monohydrate 0.28 mg 0.43 mg 0.62 mg 0.5 mg Sodium chloride 3.94 mg 6.13 mg 8.76 mg 7.01 mg
💬 Information for Patients ▾
17 PATIENT COUNSELING INFORMATION Advise the patient or caregiver to read the FDA-approved patient labeling (Patient Information and Instructions for Use). Advise patients or caregivers of the following: Preparation When preparing a volume for injection greater than 1 mL, split the volume equally between two syringes, and administer two injections. When administering the two injections, use two separate injection sites.
Take the unopened STRENSIQ vial(s) out of the refrigerator 15 to 30 minutes before injecting to allow the liquid to reach room temperature. Inspect the solution in the vial(s) for particulate matter and discoloration. Assemble injection supplies.
Administer STRENSIQ 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. Always use a new syringe and needle.
Remove vial cap, aseptically prepare the vial and insert the syringe into the vial to withdraw the prescribed dose for administration. Remove any air bubbles in the syringe and verify the correct dose. STRENSIQ vials are for one time use only.
Discard any unused product [see Dosage and Administration (2.4) ] . Administration Administer STRENSIQ within 3 hours upon removal of the vial(s) from refrigeration. Rotate the injection site to reduce the risk of lipohypertrophy and injection site atrophy.
Do NOT administer injections in areas that are reddened, inflamed, or swollen. Inject STRENSIQ subcutaneously into the determined site and properly dispose of the syringe and needle [see Dosage and Administration (2.5) ] . Hypersensitivity Reactions Including Anaphylaxis Life-threatening hypersensitivity reactions, including anaphylaxis may occur with STRENSIQ treatment.
Anaphylaxis has occurred during the early course of enzyme replacement therapy and after extended duration of therapy. Symptoms of life-threatening hypersensitivity reactions, including anaphylaxis and to seek immediate medical care should symptoms occur [see Warnings and Precautions (5.1) ] . Lipodystrophy Lipohypertrophy (enlargement or thickening of tissue) and localized atrophy (depression in the skin) have been reported at injection sites after several months.
Follow proper injection technique and rotate injection sites [see Warnings and Precautions (5.2) ] . Possible Immune-Mediated Clinical Effects Anti-drug antibodies may develop during treatment which may interfere with STRENSIQ's pharmacologic action. Inform patients or their caregivers to contact their healthcare provider if they experience worsening symptoms of HPP (e.g., increased respiratory support, increased difficulty walking, new fractures) [see Warnings and Precautions (5.4) ] .
Hypophosphatasia (HPP) Registry A registry has been established in order to better understand HPP in the population, and to monitor and evaluate long-term treatment effects of STRENSIQ. Patients and their caregivers should be encouraged to participate and advised that their participation is voluntary and may involve long-term follow-up. For more information, visit www.hppregistry.com