Recently, the Endocrine Society’s virtual Annual Meeting, dubbed ENDO 2021, took place from March 20 – 23, 2021. During the meeting, attendees discussed the latest in endocrinology research, treatment, and more. One such presentation focused around a study evaluating how vosoritide improved growth in pediatric patients with achondroplasia. While prior data showed that a single year of vosoritide injections increased height in children, Science Codex explains how the most recent study analyzed the effects of treatment over a 2-year period.

Vosoritide

According to BioMarin, vosoritide is:

an investigational analog of C-type Natriuretic Peptide (CNP)…being tested in children whose growth plates are still “open,” typically those under 18 years of age. This is approximately 25% of people with achondroplasia.

Vosoritide works by targeting the overactive growth plate signal that inhibits bone growth and development. Through this, doctors hope to relieve some of the physical symptoms (such as spinal stenosis, muscle weakness, pain) and improve height.

Prior research has shown daily vosoritide treatment to be promising. In a study evaluating the treatment in pediatric patients (under age 18) with achondroplasia, vosoritide increased height over a 1-year period. In the newer study, 119 pediatric patients received vosoritide. Of these, 58 had previously received it over the 1-year period and 61 had been on a placebo, but now received the actual treatment.

After two years, the average growth was 5.65 cm (2.2 inches). Patients also improved the ratio between their height, torso, and extremities. According to researchers, this could not only improve quality of life (QOL) but allow patients to have a higher degree of independence. With altered body proportions, patients can now participate in activities or perform tasks that they may have otherwise been unable to do independently.

Achondroplasia

FGFR3 gene mutations cause achondroplasia, a bone growth disorder which causes dwarfism. Normally, FGFR3 tells the body to create a specific protein which plays a role in bone growth, strength, and maintenance. However, the mutations cause protein overactivity, inhibiting normal development. Achondroplasia is the most common form of disproportionate dwarfism, with those who have it having a short stature with short limbs but a normal-sized torso. On average, males with achondroplasia are around 4’4, while females with achondroplasia are 4’1. Symptoms and characteristics include:

• Short fingers — the ring and middle fingers may point away from each other
• Disproportionately large head (compared to the body)
• Obesity
• Difficulty bending elbows
• Bowed legs
• Spinal stenosis, or narrowing of the spinal canal
  • Note: Spinal stenosis may cause additional symptoms, ranging from pain and muscle weakness to loss of bladder control.
• Hydrocephalus (fluid buildup within the brain)
• Low muscle tone
• Developmental delays
• Apnea (slowed or stopped breathing)
• Chronic ear infections

Learn more about achondroplasia here.