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What is Hypophosphatasia (HPP)?

Hypophosphatasia is an inherited, lifelong condition that impacts bones and bodies. Although the onset of hypophosphatasia can occur at any stage of life, the information contained here relates to two types: perinatal/infantile-onset hypophosphatasia and juvenile-onset hypophosphatasia. Perinatal/infantile-onset hypophosphatasia is defined as symptoms appearing at <6 months of age, while juvenile-onset hypophosphatasia is defined as symptoms appearing between 6 months and 18 years of age. People with hypophosphatasia have low levels of an enzyme called alkaline phosphatase that is naturally present in the body and necessary for bone creation and maintenance.

Low alkaline phosphatase

Under normal conditions, alkaline phosphatase (ALP) allows calcium and phosphate to bind together to form healthy, mineralized bones. But in hypophosphatasia, ALP is low, so less phosphate is available to bind with calcium and create strong bones. Therefore, in people with hypophosphatasia, bones can be soft or weak.

Hypophosphatasia can affect:

  • Infants and children with hypophosphatasia can have rickets and bowing of the arms and legs Bones
  • Infants with hypophosphatasia often require ventilation at birth Breathing
  • People with hypophosphatasia often have below-normal height and weight Growth
  • Mobility and Gait
People with hypophosphatasia often have difficulty walking

Hypophosphatasia is a rare genetic disorder characterized by the abnormal development of bones and teeth. These abnormalities occur due to defective mineralization, the process by which bones and teeth take up minerals such as calcium and phosphorus which are needed for proper hardness and strength. Strensiq works by replacing the alkaline phosphataseenzyme so that phosphate and calcium can bind together and improve bone health.

Strensiq® can improve bone health in people with perinatal/infantile-onset and juvenile-onset hypophosphatasia


Important Safety Information

What is Strensiq® (asfotase alfa)?

Strensiq is a prescription medicine used to treat people with perinatal/infantile- and juvenile-onset hypophosphatasia (HPP).

What are the possible side effects of Strensiq?

Strensiq may cause serious side effects, including

  • Serious allergic (hypersensitivity) reactions. Serious allergic reactions have happened in some people who use Strensiq. Stop using Strensiq and go to the nearest hospital emergency room right away if you have any of the signs and symptoms of a serious allergic reaction, including
    • Difficulty breathing
    • Swelling of your eyes, lips, or tongue
    • Hives
    • Feeling faint
    • Nausea or vomiting
    • Dizziness
    • Itching of your lips, tongue, or throat
    • Choking sensation
  • Skin thickening or pits at the injection site (lipodystrophy). Lipodystrophy at the injection site has happened several months after using Strensiq
  • Calcium buildup in your eyes and kidneys. Your healthcare provider should check your eyes and kidneys while you use Strensiq
The most common side effects of Strensiq include local skin injection-site reactions (including red skin patches, bruising, color change, pain, itching, thinning, swelling, pits, and bumps) and calcium buildup in your eyes and kidneys.

 Tell your doctor if you are pregnant or plan to become pregnant, or are breastfeeding or plan to breastfeed.

These are not all of the possible side effects of Strensiq. For more information, ask your healthcare provider or pharmacist. Call your healthcare provider for medical advice about side effects. You may report side effects to the US Food and Drug Administration at 1-800-FDA-1088.