TheraRadar
Data updated: May 26, 2026

STRENSIQ (asfotase alfa)

Trial Activity: Declining 1 active trials
Rare Disease Approved 2015-10-23

STRENSIQ is indicated for the treatment of Hypophosphatasia.

Source: FDA Label • ALEXION PHARM • Tissue-nonspecific Alkaline Phosphatase

How STRENSIQ Works

Hypophosphatasia is caused by a deficiency in TNSALP enzyme activity, which leads to the accumulation of inorganic pyrophosphate (PPi), a substance that blocks bone mineralization. STRENSIQ replaces the missing TNSALP enzyme, which catalyzes the hydrolysis of phosphomonoesters into inorganic phosphate and alcohol. By reducing elevated extracellular levels of PPi, the treatment promotes hydroxyapatite crystal growth and prevents the accumulation of unmineralized bone matrix.

Development Insights

Alexion Pharmaceuticals, Inc. conducting 14 trials (100%)
2 indications explored (Focused)
hypophosphatasia (8 trials)
hypophosphatasia (hpp) (6 trials)
2
Indications
--
Phase 3 Trials
1
Priority Reviews
10
Years on Market

Details

Status
Prescription
First Approved
2015-10-23
Patent Cliff
2022

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Routes
INJECTION
Dosage Forms
SOLUTION

Companies

Active Ingredient: ASFOTASE ALFA

STRENSIQ Approval History

2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
Original
New Indication
New Form
Label Update
20 FDA actions from 2015 to 2024 · 1 indication expansions
Jul 2024 SUPPL
Label · Labeling
Jun 2020 SUPPL
Efficacy
Jan 2018 SUPPL
Label · Labeling

What STRENSIQ Treats

1 indications

STRENSIQ is approved for 1 conditions since its original approval in 2015. These indications span multiple therapeutic areas including oncology, immunology, and more.

  • Hypophosphatasia
Source: FDA Label

STRENSIQ Boxed 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, discont...

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Clinical Trial Registry

11 trials
Trial Sponsor ID Phase Status Title
NCT06079372 CHESTNUT D8590C00004 ALXN1850-HPP-303 Ph 3 active not recruiting Phase 3 Study of ALXN1850 in Pediatric Participants With HPP Previously Treated With Asfotase Alfa
NCT04189315 REBUILD AA-HPP-406 Ph 4 withdrawn Relieving Burden of Hypophosphatasia in Adults With Functional Impairment Due to Chronic Disease
NCT02797821 results posted AA-HPP-208 Ph 2 completed Pharmacokinetic and Dose Response Study of Asfotase Alfa in Adult Patients With Pediatric-Onset Hypophosphatasia (HPP)
NCT00952484 results posted ENB-006-09 Ph 2 completed Safety and Efficacy of Asfotase Alfa in Juvenile Patients With Hypophosphatasia (HPP)
NCT00744042 results posted ENB-002-08 Ph 1, Ph 2 completed Safety and Efficacy Study of Asfotase Alfa in Severely Affected Infants With Hypophosphatasia (HPP)
NCT00739505 ENB-001-08 Ph 1 completed Safety Study of Human Recombinant Tissue Non-Specific Alkaline Phosphatase Fusion Protein Asfotase Alfa in Adults With Hypophosphatasia (HPP)
NCT01205152 results posted ENB-003-08 FD-R-003745-03 Ph 2 completed Extension Study of Protocol ENB-002-08 - Study of Asfotase Alfa in Infants and Young Children With Hypophosphatasia (HPP)
NCT01176266 results posted ENB-010-10 Ph 2, Ph 3 completed Open-Label Study of Asfotase Alfa in Infants and Children ≤ 5 Years of Age With Hypophosphatasia (HPP)
NCT01163149 results posted ENB-009-10 Ph 2 completed Safety and Efficacy Study of Asfotase Alfa in Adolescents and Adults With Hypophosphatasia (HPP)
NCT01203826 results posted ENB-008-10 Ph 2 completed Extension Study of Protocol ENB-006-09 - Study of Asfotase Alfa in Children With Hypophosphatasia (HPP)
NCT02531867 results posted AA-HPP-409 Ph 4 completed Post-approval Clinical Study of Asfotase Alfa Treatment for Patients With Hypophosphatasia (HPP) in Japan
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Active Pipeline

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Ongoing clinical trials by development phase

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Key Completed Trials

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Completed studies with published results, ranked by significance

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Trial Timeline

Full development history with FDA approval milestones

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Understanding FDA Approval Types
Count Type What it means
- ORIG Original approval - drug first enters market
- SUPPL - Efficacy New indication (new disease/condition approved)
- SUPPL - Labeling Label text changes (warnings, dosing updates)
- SUPPL - Manufacturing Production changes (new facility)
- SUPPL - Chemistry Formulation changes (new dosage strength)

Green lines in the timeline show ORIG and Efficacy approvals - the clinically meaningful milestones.

STRENSIQ FDA Label Details

Indications & Usage

FDA Label (PDF)

STRENSIQ is indicated for the treatment of Hypophosphatasia.

⚠️ 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...

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Data Sources

Data sourced from official FDA and NIH databases. Click links to verify on original sources.

How We Calculate These Metrics

Trial Activity Stage

Measures the current development activity pattern based on trial phases, status, and trends. Important: This measures R&D activity, not commercial lifecycle.

Trial statuses: "Active" means recruiting or ongoing. "Completed" means reached planned endpoint. "Terminated" means stopped early—often due to safety, efficacy, or business reasons.

  • Growth: High proportion of early-phase trials (Phase 1/2), active development
  • Expansion: Significant Phase 3 activity, approaching or pursuing approvals
  • Mature: Substantial Phase 4 post-marketing studies
  • Stable: Mixed phase distribution, steady development
  • Declining: Low active trial ratio, reduced R&D investment