Phase III Trial of Recombinant Human Parathyroid Hormone in Hypoparathyroidism: A Post-Hoc Analysis of Change in Health-State Utility Among Responders

Presentation Number: MON 348
Date of Presentation: April 3rd, 2017

Kristina Chen*1, Rebecca K. Bornheimer2, Gerry Oster2, Montserrat Vera-Llonch1 and Derek Weycker2
1Shire Human Genetic Therapies, Inc., Lexington, MA, 2Policy Analysis Inc. (PAI), Brookline, MA

Abstract

Recombinant human parathyroid hormone (rhPTH[1-84]) was recently approved in the US as an adjunct to oral calcium and active vitamin D for control of hypocalcemia in adults with hypoparathyroidism who cannot be well-controlled on calcium and vitamin D supplements alone. In a Phase III trial (NCT00732615; EudraCT2008-005063-34), 55% and 2.5% of patients randomized to receive rhPTH(1-84) (n=84) and placebo (n=40), respectively, attained the composite primary endpoint ― ≥50% reduction in oral calcium intake, ≥50% reduction in active vitamin D dose, and maintenance of albumin-corrected serum calcium level ― over the 24-week follow-up period (P<0.001) (1). The impact of attaining the composite endpoint (i.e., “responder status”), as defined above, on health-state utility is unknown and was examined in a retrospective analysis of trial data in this study. Patients participating in the Phase III trial were stratified according to whether they met the primary composite endpoint at the end-of-treatment trial visit (“responders” and “non-responders”, respectively), and health-state utility scores were estimated at baseline and the end-of-treatment visit using a crosswalk from the 36-Item Short-Form Health Survey (SF-36) to the Health Utility Index (HUI2) (2). Changes in health-state utility were examined in bivariate and multivariate analyses. Mean health-state utility among responders (n=46) increased by 0.05 (from 0.83 to 0.88) between baseline and the end-of-treatment visit (mean duration, 23 weeks), while values among non-responders (n=76) were little changed over the same period (increase <0.01, from 0.80 at baseline to 0.81 at end-of-treatment). Findings were unchanged in linear regression analysis controlling for differences in levels of calcium and vitamin D intake at baseline as well as duration of hypoparathyroidism. Successful attainment of responder status in patients with hypoparathyroidism may yield important improvements in health-state utility.

 

Disclosure: KC: Employee, Shire. RKB: Contractor, Shire. GO: Contractor, Shire. MV: Employee, Shire. DW: Contractor, Shire.