Key considerations for modelling the long-term costs and benefits of treatments for ANCA-associated vasculitis.

OBJECTIVES: Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a group of severe and chronic autoimmune diseases. Patients undergo two treatment phases: inducing remission and maintaining remission to prevent organ damage. Immunosuppressants, including glucocorticoids (GCs) are used as first-line treatment, but long-term GC use is associated with toxic effects. Novel treatments reduce or replace the need for long-term GC, and therefore can reduce GC-related toxicity. The evolving treatment landscape has presented new challenges for health technology assessment (HTA) of new treatments in AAV and long-term modelling of costs and outcomes in this disease. METHODS: Using the appraisal of avacopan in England (NICE) as a case study, this paper aims to identify the key challenges involved in the economic evaluation of new treatments for AAV, with a particular focus on the long-term modelling of the treatment costs and benefits for the purpose of HTA. The outcome of this study is a set of recommendations for modelling the cost-effectiveness of new treatments for AAV from the HTA perspective. RESULTS: The discussion focuses on the appropriate model structure, approach to modelling end-stage renal disease (ESRD) as a key determinant of costeffectiveness, capturing the impact of GC-related adverse events, and estimation of short and long-term costs of AAV. CONCLUSIONS: Economic evaluation of new treatments for AAV needs to capture all relevant downstream effects. ESRD is a key driver of cost-effectiveness but is associated with major uncertainty. Future observational studies need to offer sufficient detail to allow for differentiation in event rates across treatment options.

Avacopan as an additional therapeutic intervention to promote renal recovery in severe ANCA-associated vasculitis: A case report.

Avacopan, a C5a receptor antagonist (C5aR) presents a new therapeutic option to improve outcomes in ANCA-associated vasculitis (AAV). Here we present a case report of a patient initially requiring kidney replacement therapy (KRT), where avacopan was added as an additional adjunctive therapeutic agent late in the treatment course.

Efficacy and safety of avacopan in patients with ANCA-associated vasculitis receiving rituximab in a randomised trial.

OBJECTIVES: To evaluate the efficacy and safety of avacopan in the subgroup of patients with antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis receiving background induction therapy with rituximab in the phase 3 ADVOCATE trial. METHODS: Key efficacy outcomes were remission at week 26 and sustained remission at week 52. Additional outcomes included the Glucocorticoid Toxicity Index, estimated glomerular filtration rate, urinary albumin to creatinine ratio, health-related quality of life and safety. RESULTS: Of the 330 patients who received study medication, 214 (64.8%) received rituximab (once weekly for 4 weeks), with a mean age of 59.8 years; 163 (76.2%) had renal vasculitis and 125 (58.4%) were newly diagnosed. Remission at week 26 and sustained remission at week 52 were achieved by 83/107 (77.6%) and 76/107 (71.0%) patients in the avacopan group and 81/107 (75.7%) and 60/107 (56.1%) in the prednisone taper group, respectively. The relapse rate, recovery of renal function, speed of reduction in albuminuria and glucocorticoid toxicity favoured the avacopan group. Serious adverse events occurred in 34.6% and 39.3% of patients in the avacopan and prednisone taper groups, respectively. CONCLUSIONS: These data suggest that in patients with ANCA-associated vasculitis receiving rituximab, efficacy of treatment with avacopan compared with a prednisone taper was similar at week 26 and greater at week 52, with a favourable safety profile. In addition, avacopan was associated with improved renal outcomes and lower glucocorticoid toxicity. These results demonstrate the efficacy and safety of avacopan in patients receiving background induction therapy with rituximab. TRIAL REGISTRATION NUMBER: NCT02994927.

A projected cost-utility analysis of avacopan for the treatment of antineutrophil cytoplasmic antibody-associated vasculitis in Spain.

BACKGROUND: Antineutrophil cytoplasmic antibody-associated vasculitis (AAV) are rare autoimmune diseases characterized by inflammation of blood vessels. This study aimed to assess the cost-utility of avacopan in combination with rituximab (RTX) or cyclophosphamide (CYC) compared with glucocorticoids (GC) for the treatment of severe, active AAV in Spain. METHODS: A 9-state Markov model was designed to reflect the induction of remission and sustained remission of AAV over a lifetime horizon. Clinical data and utility values were mainly obtained from the ADVOCATE trial, and costs (€ 2022) were sourced from national databases. Quality-adjusted life years (QALYs), and incremental cost-utility ratio (ICUR) were evaluated. An annual discount rate of 3% was applied. Sensitivity analyses were performed to examine the robustness of the results. RESULTS: Avacopan yielded an increase in effectiveness (6.52 vs. 6.17 QALYs) and costs (€16,009) compared to GC, resulting in an ICUR of €45,638 per additional QALY gained. Avacopan was associated with a lower incidence of end-stage renal disease (ESRD), relapse and hospitalization-related adverse events. Sensitivity analyses suggested that the model outputs were robust and that the progression to ESRD was a driver of ICUR. CONCLUSIONS: Avacopan is a cost-effective option for patients with severe, active AAV compared to GC in Spain.

Patient-derived SLC6A1 variant S295L results in an epileptic phenotype similar to haploinsufficient mice.

The solute carrier family 6 member 1 (SLC6A1) gene encodes GAT-1, a γ-aminobutyric acid transporter expressed on astrocytes and inhibitory neurons. Mutations in SLC6A1 are associated with epilepsy and developmental disorders, including motor and social impairments, but variant-specific animal models are needed to elucidate mechanisms. Here, we report electrocorticographic (ECoG) recordings and clinical data from a patient with a variant in SLC6A1 that encodes GAT-1 with a serine-to-leucine substitution at amino acid 295 (S295L), who was diagnosed with childhood absence epilepsy. Next, we show that mice bearing the S295L mutation (GAT-1S295L/+ ) have spike-and-wave discharges with motor arrest consistent with absence-type seizures, similar to GAT-1+/- mice. GAT-1S295L/+ and GAT-1+/- mice follow the same pattern of pharmacosensitivity, being bidirectionally modulated by ethosuximide (200 mg/kg ip) and the GAT-1 antagonist NO-711 (10 mg/kg ip). By contrast, GAT-1-/- mice were insensitive to both ethosuximide and NO-711 at the doses tested. In conclusion, ECoG findings in GAT-1S295L/+ mice phenocopy GAT-1 haploinsufficiency and provide a useful preclinical model for drug screening and gene therapy investigations.

Avacopan for the treatment of ANCA-associated vasculitis: an update.

INTRODUCTION: Glucocorticoids (GC) have been part of the standard treatment of anti-neutrophil cytoplasm autoantibodies (ANCA)-associated vasculitides (AAV) for more than 60 years. Various therapeutic advances have occurred over the past 2 decades and led to a significant reduction of GC exposure, but most patients still have to suffer from complications of GC, including infections, metabolic abnormalities, and cardiovascular morbidity. In 2007, activation of the complement pathway was demonstrated to play a role in the pathogenesis of AAV. Avacopan, an oral competitive inhibitor of the C5a receptor (C5aR1, CD88), was then developed, with an additional aim to decrease the use of GC. AREAS COVERED: In this article, we briefly summarize the rationale for targeting the complement pathway in AAV, and review relevant findings from pre-clinical, phase I, II, and III studies, subsequent and more recent case reports and series on the efficacy and safety of avacopan. EXPERT OPINION: Based on the results of these studies, avacopan was approved in most countries since late 2021, as an adjunctive induction treatment for patients with AAV. Several newer questions now are pending answers, including as to how avacopan should be used in real-world practice, beyond how it was given in the original clinical trials.

AVACOPAN: A New Adjunctive Therapy for Antineutrophil Cytoplasmic Antibody-Associated Vasculitis.

Avacopan is a small-molecule complement 5a receptor (CD88) antagonist recently approved by the United States Food and Drug Administration as an adjunct therapy in combination with immunosuppressants and corticosteroids for treatment of ANCA-vasculitis. The selective ability of avacopan to inhibit the C5a receptor blocks neutrophil chemoattraction, activation, and adhesion while maintaining other beneficial complement pathways. Therefore, avacopan's unique selective property provides a breakthrough treatment for ANCA- vasculitis given that current therapies of corticosteroid treatment often lead to a decreased quality of life and a possible relapse. Clinical trials prove that avacopan is an excellent adjunctive treatment option, although it is not approved for the primary treatment of ANCA-vasculitis at this time. Initial clinical trials show substantial promise for avacopan, but additional studies with a longer duration will be needed to test for its durability and safety.

The Glucocorticoid Toxicity Index-Metabolic Domains, an abridged version of the Glucocorticoid Toxicity Index: post-hoc analysis of data from the ADVOCATE trial.

BACKGROUND: Quantifying glucocorticoid toxicity is crucial to efforts to reduce it. The Glucocorticoid Toxicity Index (GTI) measures toxicity effectively in clinical trials by calculating two scores: the cumulative worsening score (CWS) and the aggregate improvement score (AIS). However, in clinical practice, high patient volumes limit the time available for standardised assessments. We aimed to compare the GTI with an abbreviated version of the GTI, the GTI-Metabolic Domains (GTI-MD), which could help to address this issue by using data that are collected easily at routine visits and do not require additional effort from clinicians. METHODS: We did a post-hoc analysis of data from ADVOCATE, a randomised, double-blind, double-dummy, phase 3 trial in which avacopan replaced a standard prednisone taper in patients with antineutrophil cytoplasmic antibody-associated vasculitis. We calculated the cumulative worsening score (CWS) and aggregate improvement score (AIS) for each domain of the GTI-MD-comprising the BMI, glucose tolerance, blood pressure, and lipid metabolism domains of the GTI-to test its ability to differentiate the avacopan and prednisone groups by glucocorticoid toxicity. Data from two additional disease cohorts, one comprising patients with asthma and the other comprising patients with autoimmune blistering disease, constituted the validation set. FINDINGS: Complete data were available for 321 (97%) of the 330 participants comprising the intention-to-treat population in the ADVOCATE trial at week 13, and 307 (93%) at week 26; data from these individuals were included in our post-hoc analysis. In ADVOCATE, 98 (59%) of 166 participants in the avacopan group were men and 68 (41%) were women, 88 (54%) of 164 in the prednisone group were men and 76 (46%) were women; the mean age of participants was 61·2 years [SD 14·6] in the avacopan group and 60·5 years [14·5] in the prednisone group. The validation cohort included 159 patients (89 with glucocorticoid-dependent asthma, of whom 40 [45%] were men and 49 [55%] were women, and 70 with autoimmune blistering disease of the skin, of whom 30 [43%] were men and 40 [57%] were women). The Spearman's rank correlation coefficient in ADVOCATE for the GTI-MD CWS with the GTI CWS for the treatment groups combined was 0·78 (95% CI 0·75-0·81; p<0·0001). The corresponding correlation for the AIS was 0·73 (0·69-0·77, p<0·0001). The GTI-MD distinguished the groups by glucocorticoid toxicity at both 13 weeks and 26 weeks. The mean GTI-MD CWS was lower in the avacopan group than in the prednisone group, consistent with less toxicity (15·9 vs 23·0 at 13 weeks [p=0·0010]; 26·7 vs 31·7 at 26 weeks [p=0·0092]). The GTI-MD AIS values were also consistent with less toxicity in the avacopan group (2·5 vs 13·0 at 13 weeks [p=0·0003], 4·4 vs 10·1 at 26 weeks [p=0·027]). A GTI-MD score of 0 corresponded to a low likelihood of toxicity in the other GTI domains. In the validation set, the Spearman's rank correlation coefficient for the GTI-MD CWS with the GTI CWS was 0·61 (95% CI 0·50-0·70; p<0·0001) and the corresponding correlation for the AIS was 0·58 (0·47-0·68; p<0·0001). INTERPRETATION: The GTI-MD correlates well with the full GTI and could be incorporated readily into routine clinic workflows without additional input from the clinician. Using the GTI-MD on the background of electronic medical records systems could help clinicians to monitor glucocorticoid toxicity longitudinally, with the goals of preventing the burden of chronic, treatment-related harms and reducing long-term costs to health systems. FUNDING: ChemoCentryx.

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.

Glucocorticoid Toxicity Index scores by domain in patients with antineutrophil cytoplasmic antibody-associated vasculitis treated with avacopan versus standard prednisone taper: post-hoc analysis of data from the ADVOCATE trial.

BACKGROUND: The ADVOCATE trial, in which the complement C5a receptor inhibitor avacopan was compared with a standard prednisone taper in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, used the Glucocorticoid Toxicity Index (GTI) to measure glucocorticoid toxicity change. We set out to do a post-hoc analysis of the ADVOCATE data to evaluate changes in individual GTI domains and their ability to differentiate treatment groups. METHODS: The ADVOCATE trial was a phase 3, double-blind, double-dummy, randomised trial comparing oral avacopan (30 mg) twice daily for 52 weeks plus a prednisone-matching placebo for 20 weeks with oral prednisone tapered over 20 weeks plus an avacopan-matching placebo for 52 weeks in patients with ANCA-associated vasculitis. GTI data were collected within each of the included domains (BMI, blood pressure, glucose tolerance, lipid metabolism, glucocorticoid myopathy, skin toxicity, neuropsychiatric effects, and infections) at baseline, 13 weeks, and 26 weeks. In this post-hoc analysis, we calculated the cumulative worsening score (CWS) and aggregate improvement score (AIS) for each GTI domain, assessed to what extend each domain contributed to the GTI score, and which domains differentiated between the avacopan and prednisone groups. Differences in domain scores between the two groups were compared using Mantel-Haenszel χ2 tests. FINDINGS: Among the 330 patients included in the intention-to-treat population of the ADVOCATE trial, 321 (97%) had complete data at week 13 (160 in the avacopan group, and 161 in the prednisone group), and 307 (93%) had complete data at week 26 (154 in the avacopan group, and 153 in the prednisone group) and were assessed in this post-hoc study. In ADVOCATE, mean age in both groups was 61 years (61·2 years [SD 14·6] in the avacopan group; 60·5 years [14·5] in the prednisone group); 98 (59%) of 166 patients in the avacopan group were men and 68 (41%) were women; 88 (54%) of 164 patients in the prednisone group were men and 76 (46%) were women. 278 (84%) of 330 patients were White. The mean glucocorticoid use over 26 weeks was lower in the avacopan group than the prednisone group (1073 mg [SD 1669] vs 3192 mg [1174]). Significantly less glucocorticoid toxicity was observed in the avacopan group than the prednisone group by week 13 in four domains of the GTI (BMI, glucose tolerance, lipid metabolism, and skin toxicity), based on both the CWS and AIS. CWS values in the BMI, lipid metabolism, and skin toxicity domains were significantly lower in the avacopan group than the prednisone group at 26 weeks. No domain favoured the prednisone group for glucocorticoid toxicity reduction. 280 (91%) of 307 patients had glucocorticoid toxicity at 26 weeks. Blood pressure (35% in the avacopan group vs 25% in the prednisone group), infection (22% vs 24%), and lipid metabolism (20% vs 15%) contributed the most weight toward CWS values at 26 weeks. 128 (42%) of 307 patients had combinations of improvement and worsening in different domains at 26 weeks. INTERPRETATION: Replacing a standard prednisone taper with avacopan in patients with ANCA-associated vasculitis reduced glucocorticoid toxicity in multiple GTI domains. For individual patients, glucocorticoid toxicity was often nuanced, improving in some domains while worsening in others. These findings emphasise the value of a composite measure of glucocorticoid toxicity that quantifies cumulative worsening and aggregate change directly. FUNDING: ChemoCentryx.