This is a Phase 2, open-label multi-center long-term extension study, with approximately 70 subjects, to evaluate the safety and efficacy of BMN111 in children with Achondroplasia until subjects reach near-adult final height. Eligible subjects will have completed 1 year of BMN111 or placebo treatment in the 111-206 study and once enrolled in the 111-208 extension study will receive a daily dose of BMN111 by subcutaneous injection according to their age as determined by 111-206.