This is a Phase 2, Open-Label, Extension Study to Evaluate the Long-Term Safety, Tolerability, and Efficacy of BMN 111 in Children with Achondroplasia. The primary objective is to evaluate the long-term safety and tolerability of daily SC injections of BMN 111 in children with ACH who have completed two years of treatment in the 111-202 study.

Inclusion Criteria:

• Have completed 24 months of BMN 111 treatment in Study 111-202.
• Parent(s) or guardian(s) are willing and able to provide written, signed informed consent. Subjects under the age of majority are willing and able to provide written assent (if required). Subjects who reach the age of majority in their country will be asked to provide their own written consent upon reaching the legal age of majority.
• If sexually active, willing to use a highly effective method of contraception while participating in the study.
• Females >= 10 years old or who have started menses must have a negative pregnancy test at baseline and be willing to have additional pregnancy tests during the study
• Willing and able to perform all study procedures as physically possible
• Parents/caregivers willing to administer daily injections to the subjects and complete the required training.

Exclusion Criteria:

• Requires any investigational agent prior to completion of study period.
• Have a condition or circumstance that, in the view of the Investigator, places the subject at high risk for poor treatment compliance or for not completing the study.
• Concurrent disease or condition that, in the view of the Investigator, would interfere with study participation or safety evaluations for any reason.
• Permanently discontinued BMN 111 during the 111-202 study.
• Subject is pregnant at Baseline visit or planning to become pregnant (self or partner) at any time during the study.
• Current chronic therapy with restricted medications.