Zuluaga S, Hess LM, Wolowacz S, Dyachkova Y, Hawe E, Vickers AD, Kaye JA, Bertwistle D. Cost-effectiveness of olaratumab in combination with doxorubicin for the treatment of locally advanced or metastatic soft tissue sarcoma in the United States. Poster presented at the ISPOR 22nd Annual International Meeting; May 22, 2017. Boston, MA. [abstract] Value Health. 2017 May; 20(5):A108.


OBJECTIVES: Soft tissue sarcomas (STSs) are rare cancers with poor outcomes for patients with advanced disease (median overall survival [OS] is 12 – 16 months) for which the standard first-line treatment has changed little in 40 years. Recently, the United States (US) Food and Drug Administration conditionally approved olaratumab in combination with doxorubicin (OlaDox) based on a randomized, phase 2 trial in 133 patients (JGDG) that reported a significant OS benefit over single-agent doxorubicin (Dox). We investigated the cost-effectiveness of OlaDox versus Dox and five other standard-of-care regimens for patients with advanced or metastatic STS, from a US payer perspective.

METHODS: A partitioned survival model comprising three health states (Progression-free, Progressed, and Dead) was developed to estimate costs and outcomes over patients’ lifetimes. Efficacy data were based on the JGDG study and a network meta-analysis. Adverse-event rates and costs were from published sources. Progression-free survival was estimated from Kaplan-Meier curves. OS was estimated using parametric functions and age-specific mortality adjusted for STS, assuming no treatment-effect after trial follow-up. One-way sensitivity analyses (OWSAs), probabilistic sensitivity analyses, and scenario analyses were performed to evaluate the uncertainty in all model parameters. Costs and outcomes were discounted at 3% per annum.

RESULTS:
The incremental cost-effectiveness ratio (ICER) estimate for OlaDox versus Dox was $105,408 per life-year (LY) saved (95% credible interval: $62,501-$245,354). Mean costs and LYs for OlaDox increased by $133,653 and 1.27, respectively. In a fully incremental analysis, all other regimens were dominated or extendedly dominated. In OWSAs and scenario analyses, the ICER per LY saved ranged from $78,669 to $190,662.

CONCLUSIONS: Results suggested a substantial improvement in OS with OlaDox (1.27 LYs versus Dox), and an ICER of $105,408 per LY. Analyses were based on a small phase 2 trial; an ongoing phase 3 trial is expected to reduce uncertainty in future estimates.

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