Cost-effectiveness and cost-utility analysis of somatrogon once-weekly injections vs. daily growth hormone injection for treating paediatric growth hormone deficiency in Ireland.

OBJECTIVES: Paediatric growth hormone deficiency (pGHD) manifests as growth failure associated with inadequate growth hormone (GH) production. Daily injections of recombinant human GH (dGH) [somatropin] is the current standard of care, which has been shown to be well tolerated and effective, but associated with suboptimal adherence, leading to reduced effectiveness. Somatrogon, a once-weekly injectable long-acting human GH, has demonstrated clinical non-inferiority and significantly lower life interference (i.e. treatment burden) vs. somatropin in two Phase 3 studies. This work evaluated cost-effectiveness and cost-utility of somatrogon vs dGHs from an Irish payer perspective.

METHODS: A Markov model was developed for patients starting somatrogon or dGHs treatment at 3-12 years and continuing up to achievement of near adult height (NAH), with growth driven by trial-based height velocity (HV) and treatment-specific adherence. Patients could discontinue treatment at the end of Year 1 (4%). DGH adherence (95.3%-65% over treatment duration) and adherence-growth relationship were based on published evidence. Higher Year 1 adherence of 4%, tapering over time, for somatrogon vs. dGHs was based on clinical consultation. Treatment costs, monitoring costs and costs due to different wastage types (device setting and adherence) were sourced from local data. Health utilities based on height and injection frequency were derived from published literature. Scenario analysis, deterministic and probabilistic sensitivity analysis were performed.

RESULTS: Somatrogon treatment led to 1.87-3.66 cm greater NAH gain and 0.21-0.50 higher quality adjusted life years (QALYs) vs. dGHs, across the base case and scenarios evaluated. Somatrogon treatment was associated with cost savings of €5,699-€21,974 and lower cost per cm gained vs. dGHs (€197-€527), per patient. Somatrogon was cost-effective vs. dGHs, with the result consistent across the sensitivity analyses conducted.

CONCLUSION: Somatrogon weekly injections were estimated to result in higher NAH, higher QALYs, lower overall costs and lower costs per cm gained than dGHs, in pGHD.