A New Opportunity to Help Manage Your or Your Child’s Hypophosphatasia

If you or your child is living with hypophosphatasia (HPP) — a rare, inherited condition that makes it difficult for the body to create strong bones and teeth — it can feel isolating and near impossible to manage. Because HPP looks different for each person living with the condition, it can also be challenging to diagnose and treat. But you do not need to navigate this journey on your own. Keep reading to learn more about this rare condition, including a potential new investigational medication that may help people living with HPP better manage the debilitating disease. 

What is HPP? 

HPP is a rare genetic disorder caused by a mutation in the gene coding for alkaline phosphatase (ALP). This gene is responsible for helping the body form strong bones and teeth, but if someone has low ALP levels, it may be difficult for their body to do so. This results in bone injuries, fractures, and tooth loss. But HPP can also encompass a wide range of symptoms — from chronic pain and muscle weakness to fatigue and brain fog –– and some individuals may not have symptoms at all.

What are the symptoms of HPP?

It’s important to remember that HPP symptoms can look different for everyone living with it, so you or your child may have different experiences from others living with the disease — even other family members. While the severity of signs and symptoms can vary from person to person — age can also play a role — there are symptoms to look out for during pregnancy, as well as in infancy, childhood, and adulthood. Here are common symptoms that may arise during each of these stages: 

• In pregnancy: Perinatal HPP is also called HPP in utero and it can be difficult to recognize and diagnose. Perinatal HPP is often detected by magnetic resonance imaging (MRI), and your doctor would check the fetus for short or bowed limbs and underdeveloped ribs. 
• In infancy: Infants may not grow at the expected rate for their age, resulting in short limbs, difficulty breathing, and soft skull bones. 
• In childhood: For children and teens, symptoms may include broken bones, early baby tooth loss, muscle and joint pain, weakness and fatigue, or slow growth.
• In adulthood: Adults may experience challenges in their daily lives, such as difficulty walking, running, climbing stairs, or bending. Symptoms may also include severe bone or joint pain, inflammation, gum disease, or softening bones. 

How is HPP diagnosed? 

HPP is a genetic disorder, which means that more than one person in the same family may have the condition. If you or someone in your family has either been diagnosed with HPP or experiences symptoms, the next step may be seeking out medical treatment for yourself or your child, or talking to your loved ones about the condition and encouraging them to speak to their doctor.

While you or your child’s primary care provider may be a good place to start, a specialist who is trained to diagnose and treat rare genetic health conditions — such as an endocrinologist, geneticist, or orthopedist — is more likely to understand HPP. 

A specialist may first conduct a physical exam to determine whether you or your child shows signs of HPP, but lab tests usually confirm a diagnosis. Common tests include a blood or urine test, which will assess for low ALP levels, or genetic testing, which will be able to determine whether there are ALP gene mutations.

Because it’s a rare disease, and its symptoms overlap with other health conditions, HPP is often misdiagnosed. Some common misdiagnoses include arthritis, fibromyalgia, osteoporosis, and rickets. 

How is HPP treated? 

Despite the severity and long-term impact of symptoms, there is currently no cure for this rare, debilitating disease. 

STRENSIQ^® (asfotase alpha) is the only medication approved by the Food and Drug Administration (FDA) to treat HPP. Other treatment options include respiratory support, orthopedic intervention, vitamin B6 supplements, and over-the-counter pain relief medication. While there is currently one FDA-approved medication, there is no one-size-fits-all treatment approach. 

That’s why clinical research studies are an important consideration for people living with HPP, as they serve a critical function in discovering effective new treatments. They also provide people with an opportunity to try new medications that may be a better fit than what limited treatments are currently available. Participating in a clinical research study brings researchers closer to patients, as well as closer to finding more effective treatments for HPP while providing new hope and improved quality of life for those living with the condition. 

What are the Hickory, Chestnut, and Mulberry Studies? 

Researchers are studying a new investigational medication that may help children, adolescents, and adults with HPP. The medication is currently being investigated in three clinical trials: the Hickory Study, for adolescents between the ages of 12 and 17 years old and adults 18 years or older, and the Chestnut and Mulberry studies, for children between the ages of 2 and 12 years old. 

To qualify for the Hickory and Mulberry studies, individuals cannot have previously received treatment with STRENSIQ (asfotase alfa). However, individuals may have received treatment with STRENSIQ to qualify for the Chestnut Study. All three trials are evaluating the safety and effectiveness of ALXN1850, an investigational medication that can be administered at home once every two weeks. 

Those who qualify for and enroll in the Hickory Study will randomly receive either the investigational medication or a placebo. Those who qualify for and enroll in the Chestnut Study will randomly receive either the investigational medication or STRENSIQ. Those who qualify for and enroll in the Mulberry Study will randomly receive either the investigational medication or a placebo. The placebo looks the same as the investigational medication but contains no active ingredients. 

In all three studies, you or your child will have the opportunity to stop the placebo or STRENSIQ and start the investigational medication, or continue to receive the investigational medication, during the open-label extension period at no cost for approximately two and a half years. 

If you or someone you love has been diagnosed with HPP, there is always hope. To learn more about the Hickory Study and to see if you or your child qualifies, click here. To learn more about the Chestnut Study and if you or your child is eligible, click here. To learn more about the Mulberry Study and if you or your child are eligible, click here.