Strensiq, or asfotase alfa, is a beacon of hope for individuals living with hypophosphatasia (HPP).
This highly specialized medication helps manage the symptoms of HPP, a rare metabolic disease that affects bone and teeth development.
Whether you or a loved one has recently been prescribed Strensiq, this comprehensive guide will walk you through crucial points you need to know - from understanding what it is and how it works to using, storing, and even traveling with it. After all, understanding your medication is an important part of managing your health.


Travel coolers for Strensiq and refrigerated drugs

What is Strensiq?

Strensiq is the first and only medicine available to treat people with perinatal, infantile, and juvenile-onset hypophosphatasia. Its active ingredient is asfotase alfa, and it's manufactured by Alexion Pharmaceuticals.


Hypophosphatasia (HPP) is a rare, inherited metabolic disorder that affects the development of bones and teeth. This condition is caused by mutations in a gene responsible for producing an enzyme called tissue nonspecific alkaline phosphatase (TNSALP).
This enzyme plays a crucial role in the process of mineralization, which is the deposition of calcium and phosphate minerals in bones and teeth, providing them with their hardness and strength.
In individuals with HPP, the mutations cause a deficiency or complete absence of TNSALP, leading to a failure of proper mineralization.
The symptoms and severity of HPP vary greatly from person to person, depending on the specific type of the disorder. They can range from severe and life-threatening in infancy to milder symptoms appearing later in adulthood, including:

  • Poor bone development, leading to soft and fragile bones
  • Delayed growth and development in infants and children
  • Bone pain and muscle weakness
  • Premature loss of baby and adult teeth
  • Breathing difficulties and other respiratory problems, especially in severe cases
  • Various neurological complications like seizures or craniosynostosis
  • Others 

Unfortunately, there's currently no cure for HPP, but treatments like Strensiq (asfotase alfa) help manage the symptoms and improve the quality of life.

How Does Strensiq Work?

Strensiq is an enzyme replacement therapy. Its active ingredient, asfotase alfa, works by replacing the missing or deficient enzyme (alkaline phosphatase) in people with HPP.
It's a synthetic, man-made version of the TNSALP enzyme, created using recombinant DNA technology.
When administered, asfotase alfa binds to the surfaces of bones and teeth where mineralization occurs and promotes the normal metabolic processes that were disrupted due to the lack of TNSALP. This improves the mineralization of bones and teeth, which in turn helps to alleviate HPP symptoms.

How to Use Strensiq?

Strensiq is usually a long-term treatment. The frequency of administration is based on individual needs, but it can be as often as six times a week.
The specifics of the treatment plan, such as dosage and frequency, must be determined by a healthcare provider based on your individual needs. For example, Strensiq is dosed in milligrams per body weight, so the dosage may change as your weight changes.
Below is some general information about how to use, store, and handle your new HPP medicine.

How is it administered?

Strensiq is a prescription medicine delivered via subcutaneous injections (just under the skin), either by a healthcare provider or the patient themselves after receiving proper injection training.
It is commonly injected in the stomach area, upper arms, upper legs, or buttocks. Rotating the injection site at each injection is essential to avoid injection site reactions.
Strensiq comes in small vials (glass bottles) and must be drawn and injected with single-use, disposable syringes.

How to Store Strensiq?

Asfotase alpha, the active ingredient in Strensiq, is a biological drug and a temperature-sensitive medicine.
It must be stored in the refrigerator at a temperature between 36°F to 46°F (2°C to 8°C) and can only stay at room temperature for a maximum of 3 hours.
Additionally, Strensiq must be protected from light when stored (keep it in its original carton).
The manufacturer also warns patients not to freeze their medicine. Avoid storing it near the freezer compartment or in direct contact with ice.

Traveling with Strensiq

Because of its need for refrigeration, traveling with Strensiq requires additional considerations, but there's no need to worry.
The most important thing to remember is that Strensiq needs to be stored at cool temperatures, ideally between 36°F to 46°F (2°C to 8°C).
Most people traveling with refrigerated drugs choose to invest in a portable cooler, such as the ones from 4AllFamily. It’s by far the most reliable and convenient solution.
When flying, always pack your vials of Strensiq in your carry-on. Do not leave them in checked luggage because the hold’s atmospheric and temperature conditions could damage your medicine.

Related article: How to Travel With Syringes and Injectable Drugs?
You might need a letter from your healthcare provider explaining your need for the medication, so be sure to ask them about it before departure. Your Strensiq starter kit includes a TSA travel letter that you can bring along too.
Also, always keep your Strensiq in its original packaging with the attached prescription label. This can help smooth checks.
Lastly, plan your dosing schedule carefully, considering different time zones to ensure you don't miss any doses while traveling internationally. And it's always a good idea to pack extra medication in case your return trip gets delayed.
Related article: How to Travel With Refrigerated Medications?

Travel coolers for refrigerated drugs 

How Much Does Strensiq Cost?

Strensiq stands among the most expensive medicines due to its highly specialized formulation. Its annual cost can escalate to several hundred thousand dollars with no lower-cost generic alternative.
However, the exact cost can vary based on your dosage and the specific terms of your health insurance plan.
Talk to your healthcare provider or pharmacist if you're concerned about affording Strensiq. They can help you find resources for financial assistance or alternative payment options.

Side Effects

Like all medications, Strensiq (asfotase alfa) can have side effects, although not everyone gets them. Potential side effects include:

  • Injection site reactions
  • Hypersensitivity reactions
  • Fever
  • Headache
  • Vomiting, diarrhea, and gastrointestinal issues
  • Calcium build-up
  • Hives
  • Difficulty breathing
  • Swelling
  • Dizziness
  • Choking sensation
  • Vision changes
  • Urination issues
  • Allergic reaction 

You may experience other side effects. Always inform your doctor if you notice any new or unusual symptoms while taking Strensiq.
Living with hypophosphatasia can be challenging, but treatments like Strensiq help manage the symptoms and improve quality of life.
Remember, this article is intended to be informative but doesn't replace professional medical advice. Always consult your healthcare provider for information tailored to your health situation.

Related article: How to Get Travel Insurance for Preexisting Medical Conditions?
Share your experience with others: are you using Strensiq for hypophosphatasia? What do you think about this medicine?

July 11, 2023

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The information presented in this article and its comment section is for informational purposes only and is not intended as a replacement for professional medical advice. Always consult with a qualified healthcare provider for any medical concerns or questions you may have.