OBJECTIVES: TED, an autoimmune, inflammatory disease, is characterized by retro-orbital tissue expansion and devastating changes in facial appearance and visual function. The Graves’ Ophthalmopathy QOL (GO-QOL) questionnaire is TED specific but has not been mapped to health state utility (HSU) scores. Recently, mean score for moderate-severe TED was assessed as 0.44. To quantify QALY improvements with teprotumumab, we correlated and bridged GO-QOL values with TTO-derived utility scores.

METHODS: GO-QOL data from 2, 24-week randomized, masked, placebo-controlled teprotumumab trials (n=171) were compared with TTO values assessed from 6 health states of the trial patients based on proptosis/diplopia severity. R Project^® was used for statistical assessments.

RESULTS: Baseline GO-QOL scores were consistent with HSU scores across TED severity levels indicating generally worse severity was associated with lower/worse GO-QOL. Less discrimination in GO-QOL was noted in the intermediate health states. GO-QOL scores were highly positively correlated with utility scores of the 6 health states (mean (r²=0.76) and median (r²=0.88), translating to a 1-point change in mean GO-QOL equaling a 0.013 utility change. Increasing diplopia had a major impact on worsening QOL, particularly as noted by changes in the visual GO-QOL subscale. Moving from a no diplopia state to a constant state worsened overall GO-QOL by 20.42 points. Only 1/79 (1.3%) teprotumumab patients progressed to a more severe state versus 13/78 (16.7%) for placebo. This indicates teprotumumab QALY gain over 3 years was 0.74 and 0.51 when placebo adjusted. The 3 year QALY was 2.06 for teprotumumab and 1.55 for placebo.

CONCLUSIONS: TED produces significant disutility and the clinical trial reported GO-QOL scores significantly correlated with TTO derived utility values. Declining utility values are associated with worsening GO-QOL and increasing TED severity. Teprotumumab is estimated to improve placebo adjusted QALY by 0.51 over 3 years. These bridging analyses serve as a basis for future TED QALY gain calculations.