The impact of treatment with avacopan on health-related quality of life in antineutrophil cytoplasmic antibody-associated vasculitis: a post-hoc analysis of data from the ADVOCATE trial

Background: Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis is characterised by inflammation and destruction of small to medium sized blood vessels. In the previously reported ADVOCATE study, a phase 3 double-blind, double-dummy randomised controlled trial of patients with newly diagnosed or relapsing ANCA-associated vasculitis, the oral selective complement 5a receptor inhibitor avacopan was shown to be non-inferior with regard to remission induction at week 26 and superior with regard to sustained remission at week 52, compared with a prednisone taper in a standard of care regimen. In this Article, we report an in-depth analysis of prespecified and exploratory patient-reported outcomes from the ADVOCATE study, measuring health-related quality of life and health utilities. Methods: We did a post-hoc analysis of patient-reported outcome data from the ADVOCATE study (NCT02994927) of patients with newly diagnosed or relapsing ANCA-associated vasculitis. We analysed summary scores and individual domain scores for the prespecified health-related quality of life outcomes from ADVOCATE, which were evaluated at weeks 26 and 52 by use of the Medical Outcomes Survey 36-Item Short Form Health Survey (SF-36) version 2, the EuroQol 5-Dimensions 5-Levels Questionnaire (EQ-5D-5L), and the EQ-5D health utility measure, assessed in the modified intention-to-treat population. We also calculated the Short Form 6 Dimension (SF-6D) score as an additional health utility measure. We evaluated the proportion of patients who reported scores that met or exceeded minimum clinically important differences in health-related quality of life, and we compared scores to normative values (age-specific and sex-specific scores from healthy populations from the USA matched to the protocol population). We also evaluated the proportion of patients who reported scores that met or exceeded minimum important difference in health utility scores. Findings: 331 patients were enrolled in the ADVOCATE trial, of whom 166 were in the avacopan group and 165 were in the prednisone standard of care group. In the avacopan group, the mean age was 61·2 years (SD 14·6), 98 (59%) of 166 patients were men, 68 (41%) were women, and 138 (83%) were White; in the prednisone group, the mean age was 60·5 years (14·5), 88 (54%) of 164 patients were men, 76 (46%) were women, and 140 (85%) were White. Patients treated with avacopan received approximately 2500 mg less median total prednisone up to week 52. Least squares means difference from baseline in physical component summary scores were significantly greater in patients in the avacopan group compared with those in the prednisone group at weeks 26 and 52, as well as in five of eight SF-36 domains at week 26 and two of eight SF-36 domains at week 52. The proportion of patients reporting scores equal to or greater than normative values was higher in the avacopan group than in the prednisone group across all SF-36 domains at both week 26 and 52, although the differences were not statistically significant with the exception of the role physical and vitality domains at week 26. Least squares means change from baseline in EQ-5D-5L visual analogue scale, EQ-5D health utility scores, and SF-6D health utility scores were significantly greater at week 52 in the avacopan group compared with the prednisone group. Interpretation: Patients with ANCA-associated vasculitis who received avacopan reported statistically significant and clinically meaningful improvements in health-related quality of life at 26 and 52 weeks and in health utility EQ-5D and SF-6D scores at 52 weeks. These patient-reported outcomes complement investigator assessments and support the efficacy of avacopan in patients with ANCA-associated vasculitis with use of lower prednisone doses. Funding: ChemoCentryx.