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

To join this study, children must have already completed one of two previous studies (called 111-303 or 111-212) on vosoritide. They also need to have open growth plates in their bones, which means they are still growing. Their parents or guardians must be willing to give permission and ensure their child follows all study instructions.

If a girl is 10 years old or older, or has started her periods, she will need to have pregnancy tests during the study. If she is sexually active, she must agree to use effective birth control. Parents or guardians must be able to give daily injections to the child and be willing to be trained on how to do this.

There are also some reasons why someone couldn't join. For example, if they stopped treatment in a previous study, their growth has slowed down a lot, or their growth plates have closed. Other reasons include planning to have surgery that affects bones or taking certain other medications. If a child has cancer, a serious allergy to the medication, or if a participant is pregnant or breastfeeding, they cannot join. The study also can't accept anyone with a health condition that would make it difficult or unsafe to take part.

If you decide to take part in this study, your child will receive daily injections of vosoritide, which you, as a parent or guardian, will be trained to give. You'll need to make sure your child attends regular check-ups at the study clinic. These visits will involve various tests and measurements to see how your child is growing and to check for any side effects. For example, they might have X-rays of their hand to check their bone growth. If applicable, girls will have pregnancy tests at the start and during the study. You'll also be asked to help your child complete any necessary procedures to the best of their ability. The total duration of participation will be explained in detail by the study team, but it is a long-term study following on from previous research.