Discuss vosoritide therapy with the parents of a child with achondroplasia — OSCE

Candidate brief

You are the paediatric registrar in the skeletal dysplasia clinic. The task is to explain vosoritide therapy to the parents of a two-year-old with achondroplasia in plain language, convey honestly what the treatment can and cannot achieve, weigh the daily injection burden against the growth benefit, and integrate the decision with the broader surveillance plan — all while acknowledging the parents' anxiety and supporting a shared decision rather than pressuring them. The consultation is ten minutes. [1] [2]

Key teaching points for the candidate

Vosoritide is a C-type natriuretic peptide analogue given as a once-daily subcutaneous injection that overrides the FGFR3 brake on chondrocyte proliferation, the mechanism that arrests endochondral bone growth in achondroplasia. A randomised, double-blind, phase three placebo-controlled trial showed a sustained increase in annualised growth velocity in treated children, making it the first disease-modifying therapy directed at the underlying mechanism. The candidate must set realistic expectations: vosoritide increases growth velocity but does not normalise adult height, does not address the complications of achondroplasia, and requires a daily injection for years. [2] [3]

The candidate must frame the decision as one arm of a broader care plan. Vosoritide runs in parallel with — not instead of — the surveillance that defines achondroplasia care: foramen magnum and sleep assessment in infancy, syndrome-specific growth plotting, ENT and audiology review, and orthopaedic management of limb deformity. The parents should understand that choosing to start, delay, or decline vosoritide does not affect access to any other part of the care plan, and that the decision can be revisited as their daughter grows and as longer-term evidence accumulates. [1] [4]

Communication tasks

The candidate should explore the parents' understanding and their specific concerns before giving information, so the explanation meets their priorities rather than overwhelming them. The candidate should explain in plain language what vosoritide is and how it works — overriding the genetic "brake" on bone growth — and give an honest account of what it achieves (increased growth velocity, potentially greater adult height) and what it does not (it does not cure achondroplasia, normalise height, or treat the complications). [2] [3]

The candidate should acknowledge the practical and emotional burden of a daily injection on a two-year-old and on the family, and describe the support available — including injection technique teaching, needle-length options, and the specialist team's availability. The candidate should offer a balanced view that does not pressure the family either way, invite questions, check understanding using teach-back, and offer a follow-up appointment and written information so the decision is not rushed. The candidate should close by affirming that whatever they choose, the surveillance and support plan continues unchanged. [1] [4]