Long-Term Extension Study of Vosoritide to Treat Children With Hypochondroplasia

What Was Tested

The trial (phase 3) is built around Vosoritide.

It had 1 arm (groups): Vosoritide (experimental).

Open-label active drug.

The registry classes the interventions as drug.

Who Took Part

140 planned participants were the target.

It was open to people of any sex.

Healthy volunteers were not accepted; participants needed the condition being studied.

Examples of who could join: Participants must have completed the Week 52 visit for 111-303 or 111-212 and have open epiphyses as assessed by left hand antero-posterior (AP) X-rays. Participants are willing and able to perform all study procedures as physically possible. Parent(s) or caregiver(s) are willing to administer daily injections to the participants and willing to complete the required training.

The full record lists 6 inclusion and 10 exclusion criteria; among the exclusions: permanently discontinued study treatment in the studies 111-303 or 111-212; taking or planning to take any prohibited medications; planned or expected to have limb-lengthening surgery during the study period.

How the Study Was Run

The set-up was single-group and open-label.

Nothing was hidden in this open-label Vosoritide study: the participants and staff both knew the treatment.

Everyone received the same intervention, so there was no separate comparison group inside the trial.

It started in 2025-06-20 with completion listed for 2044-10.

It ran at 30 sites in United States (10), France (4), Japan (4), Canada (3), Germany (3) and Italy (3).

Its stated primary purpose is treatment.

What Was Measured

It also tracked 11 secondary outcomes, for example Evaluate the maintenance effect of vosoritide treatment on standing height, Evaluate the maintenance effect of vosoritide treatment on standing height Z-score, Evaluate long-term effect of vosoritide treatment on growth velocity, Evaluate long-term effect of vosoritide treatment on body proportionality, Evaluate long-term effect of vosoritide treatment on bone age versus chronological age and Evaluate long-term effect of vosoritide treatment on bone metabolism biomarkers.

What This Means in Plain Language

Put simply, this is a phase 3 trial of Vosoritide in 140 people.

Its status is enrolling by invitation; no results are posted to the registry yet, so nothing here describes outcomes.

More context: the Vosoritide compound page, all human trials.