International expert opinion on the considerations for combining vosoritide and limb surgery: a modified delphi study

Achondroplasia is the most common form of skeletal disorder with disproportionate short stature. Vosoritide is the first disease-specific, precision pharmacotherapy to increase growth velocity in children with achondroplasia. Limb surgery is a standard approach to increase height and arm span, improve proportionality and functionality, as well as correcting deformities. The aim of this study was to gain expert opinion on the combined use of vosoritide and limb surgery in children and adolescents with achondroplasia.

An international expert panel of 17 clinicians and orthopaedic surgeons was convened, and a modified Delphi process undertaken. The panel reviewed 120 statements for wording, removed any unnecessary statements, and added any that they felt were missing. There were 26 statements identified as facts that were not included in subsequent rounds of voting. A total of 97 statements were rated on a ten-point scale where 1 was 'Completely disagree' and 10 'Completely agree'. A score of ≥ 7 was identified as agreement, and ≤ 4 as disagreement. All experts who scored a statement ≤ 4 were invited to provide comments.

There was 100% agreement with several statements including, "Achieve a target height, arm span or upper limb length to improve daily activities" (mean level of agreement [LoA] 9.47, range 8-10), the "Involvement of a multidisciplinary team in a specialist centre to follow up the patient" (mean LoA 9.67, range 7-10), "Planning a treatment strategy based on age and pubertal stage" (mean LoA 9.60, range 8-10), and "Identification of short- and long-term goals, based on individualised treatment planning" (mean LoA 9.27, range 7-10), among others. The sequence of a combined approach and potential impact on the physes caused disagreement, largely due to a lack of available data.

It is clear from the range of responses that this modified Delphi process is only the beginning of new considerations, now that a medical therapy for achondroplasia is available. Until data on a combined treatment approach are available, sharing expert opinion is a vital way of providing support and guidance to the clinical community.