Comparability of patients with ANCA-associated vasculitis enrolled in clinical trials or in observational cohorts

OBJECTIVES

To analyse the differences between patients with granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA) entered into randomised clinical trials (RCTs) and those followed in large observational cohorts.

METHODS

The main characteristics and outcomes of patients with generalised and/or severe GPA or MPA with a five-factor score ≥ 1 enrolled in the French Vasculitis Study Group (FVSG) or the US-Canadian-based Vasculitis Clinical Research Consortium cohorts were compared to those enrolled in one of 2 FVSG clinical RCTs (WEG91, WEGENT) or 3 European Vasculitis Society clinical trials (CYCLOPS, CYCAZAREM, IMPROVE).

RESULTS

657 patients (65.3% with GPA) in RCTs were compared to 437 in cohorts (90.6% with GPA). RCT patients were older at diagnosis than the cohort patients (56.6 ± 13.9 vs. 46.8 ± 17.3 years), had higher Birmingham vasculitis activity score (19.5 ± 9.1 vs. 16.9 ± 7.4), and more frequent kidney disease (84.0% vs. 54.9%) but fewer ear, nose, and throat symptoms (56.8% vs. 72.2%). At 56 months post-diagnosis, mortality and relapse rates, adjusted for age and renal function, were higher for patients with GPA in RCTs vs. cohorts (10.7% vs. 2.5% [p=0.001] and 22.5% vs. 15.6% [p=0.03], respectively) but similar for patients with MPA (6.2% vs. 6.6% [p=0.92] and 16.6% vs. 10.1% [p=0.39], respectively).

CONCLUSIONS

Patients with GPA or MPA in RCTs and those in observational cohorts show important differences that should be remembered when interpreting results based on these study populations.

Long-term follow-up of cyclophosphamide compared with azathioprine for initial maintenance therapy in ANCA-associated vasculitis

BACKGROUND AND OBJECTIVES

Treatment with azathioprine within 3 months of remission induction with cyclophosphamide is a common treatment strategy for patients with ANCA-associated vasculitis. This study comprised patients undergoing long-term follow-up who were randomly allocated to azathioprine after 3-6 months or after 12 months of cyclophosphamide treatment.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Patients from 39 European centers between 1995 and 1997 with a new diagnosis of ANCA-associated vasculitis that involved the kidneys or another vital organ were eligible. At the time of diagnosis, participants were randomly allocated to convert to azathioprine after 3-6 months (the azathioprine group) or after 12 months of cyclophosphamide (the cyclophosphamide group). Patients who did not achieve a remission within 6 months were excluded. This study assessed relapses, ESRD, and death during long-term follow-up.

RESULTS

Patients were allocated to the azathioprine group (n=71) and the cyclophosphamide group (n=73). Of these patients, 63 (43.8%) developed a relapse, 35 (24.3%) developed a renal relapse, 13 (9.0%) developed ESRD, and 21 (14.6%) died. Although there were worse outcomes in the azathioprine group, none were statistically significant. The subdistribution hazard ratio [sHR] for relapse was 1.63 (95% confidence interval [95% CI], 0.99 to 2.71), the composite of relapse or death hazard ratio [HR] was 1.59 (95% CI, 1.00 to 2.54), the ESRD sHR was 1.71 (95% CI, 0.56 to 5.19), and the death HR was 0.75 (95% CI, 0.32 to 1.79).

CONCLUSIONS

It remains uncertain whether converting to azathioprine after 3-6 months of induction cyclophosphamide therapy is as effective as converting after 12 months. Outcomes are still poor for this group of patients and further research is required to determine the optimal timing of maintenance therapy.

Pulse versus daily oral cyclophosphamide for induction of remission in ANCA-associated vasculitis: long-term follow-up

INTRODUCTION

The previously reported randomised controlled trial of a consensus regimen of pulse cyclophosphamide suggested that it was as effective as a daily oral (DO) cyclophosphamide for remission induction of antineutrophil cytoplasm autoantibodies-associated systemic vasculitis when both were combined with the same glucocorticoid protocol (CYCLOPS study (Randomised trial of daily oral versus pulse Cyclophosphamide as therapy for ANCA-associated Systemic Vasculitis published de groot K, harper L et al Ann Int Med 2009)). The study had limited power to detect a difference in relapse. This study describes the long-term outcomes of patients in the CYCLOPS study.

METHODS

Long-term outcomes were ascertained retrospectively from 148 patients previously recruited to the CYCLOPS Trial. Data on survival, relapse, immunosuppressive treatment, cancer incidence, bone fractures, thromboembolic disease and cardiovascular morbidity were collected from physician records retrospectively. All patients were analysed according to the group to which they were randomised.

RESULTS

Median duration of follow-up was 4.3 years (IQR, 2.95-5.44 years). There was no difference in survival between the two limbs (p=0.92). Fifteen (20.8%) DO and 30 (39.5%) pulse patients had at least one relapse. The risk of relapse was significantly lower in the DO limb than the pulse limb (HR=0.50, 95% CI 0.26 to 0.93; p=0.029). Despite the increased risk of relapse in pulse-treated patients, there was no difference in renal function at study end (p=0.82). There were no differences in adverse events between the treatment limbs.

DISCUSSION

Pulse cyclophosphamide is associated with a higher relapse risk than DO cyclophosphamide. However, this is not associated with increased mortality or long-term morbidity. Although the study was retrospective, data was returned in 90% of patients from the original trial.

UGT1A polymorphisms in a Swedish cohort and a human diversity panel, and the relation to bilirubin plasma levels in males and females

OBJECTIVES

The objective of this study was to investigate the prevalence of different polymorphisms and haplotypes associated with individual variations in pharmacokinetics and drug toxicity in the uridine-diphosphate glucuronosyl transferase (UGT) 1A gene in a Swedish cohort (248 healthy volunteers) and in 14 different ethnic groups. We also estimated UGT1A genotype-dependent glucuronidation efficiency using the endogenous substrate bilirubin as an indicator.

METHODS

Pyrosequencing-based genotyping assays were used to determine the different polymorphisms and haplotypes.

RESULTS

Haplotype analysis of the UGT1A1 (*1*28), UGT1A6 (*1*2), and UGT1A7(*1*2*3*4) allelic variants showed that three major haplotypes constituted 84% of the allelic variants in the cohort. We identified 15 haplotypes altogether from all groups, including previously undescribed haplotypes. Testing for the association of genotype and total bilirubin levels (nonfasting) in plasma disclosed that homozygous carriers of the TA allele, irrespective of haplotype combinations, had increased levels of bilirubin compared with noncarriers, but a gender-associated difference was observed.

CONCLUSIONS

In a Swedish cohort, several genetic variants in the UGT1A gene are common, but prevalence in a population may differ because of ethnicity. A phenotype based on bilirubin levels has limitations in serving as an indicator of pharmacogenetic differences in glucuronidation due to the influence of gender. Because of possible substrate overlap regarding different UGT1A isoforms, determination of haplotypes of potential cis-acting polymorphisms in the UGT1A gene should be considered in pharmacogenetic association studies regarding drugs that undergo glucuronidation.

Prevalence of Stroke and Vascular Risk Factors among First-Degree Relatives of Stroke Patients and Control Subjects

BACKGROUND

Genetic and environmental factors may be of importance for stroke risk. We assessed the prevalence of stroke and vascular risk factors among first-degree relatives and spouses of stroke patients and control subjects.

METHODS

As a part of the Lund Stroke Register study, we asked 925 consecutive patients with first-ever stroke and 286 control subjects to complete a questionnaire about all their first-degree relatives and spouses. The questionnaires addressed whether these relatives had been affected by stroke or TIA, hypertension, heart disease, diabetes mellitus, and if they were smokers.

RESULTS

A total of 606 patients and 261 control subjects returned the questionnaire, providing information on 4,972 first-degree relatives and 738 spouses. The prevalence of stroke or TIA was 12.3% among first-degree relatives of patients and 7.5% among first-degree relatives of control subjects (OR 1.74, 95% CI 1.36-2.22). Corresponding results for hypertension were 21.0 and 16.7% (OR 1.33, 95% CI 1.10-1.60). The prevalences of heart disease, diabetes mellitus and smoking did not differ significantly between first-degree relatives of patients and control subjects. Spouses of patients and control subjects had similar prevalences of stroke or TIA and vascular risk factors.

CONCLUSIONS

The prevalences of stroke or TIA and hypertension are higher among first-degree relatives of stroke patients than among first-degree relatives of control subjects. This, and the lack of differences between spouses of patients and control subjects, indicates that an increased risk of stroke may in part be explained by heritability of hypertension.

Combination of nitrates with other antianginal drugs

The choice between beta-blockers, long-acting nitrates, and calcium antagonists for prophylactic treatment of stable angina pectoris is determined by several factors, including specific indications for and contraindications to a particular drug. In severe cases of angina, combined treatment is common. The theoretical advantages of combined therapy seem attractive; however, studies documenting the effects of some combinations are few or lacking. Combined use of nitrates and beta-blockers is a rational approach, because the pharmacological actions of the 2 drugs produce complementary haemodynamic effects. In short term studies favourable effects have been documented. Positive, but more variable effects have also been reported during long term treatment. Additive effects of nitrates and calcium antagonists have been found in angina produced by coronary artery spasm, but the effects of the combination in stable angina pectoris are not well documented. The combination may be more or less attractive, depending on the profile of action of the particular calcium antagonist used. It should be stressed that there are no studies of the efficacy of long term treatment with the combination of nitrates and calcium antagonists. Triple treatment is based more on clinical experience than on the effect documented in properly designed clinical studies. Even if additional beneficial effects can be obtained in patients on maximal doses of beta-blockers and nitrates when receiving calcium antagonists, it has been shown that triple therapy may not be optimal for certain patients.