Comparison of Long-term Ambulatory Function in Patients with Duchenne Muscular Dystrophy Treated with Eteplirsen and Matched Natural History Controls.

BACKGROUND: Duchenne muscular dystrophy (DMD) is a rare, X-linked, fatal, degenerative neuromuscular disease caused by DMD gene mutations. A relationship between exon skipping and dystrophin production in exon 51-amenable patients treated with eteplirsen (EXONDYS 51®) is established. Once-weekly eteplirsen significantly increased dystrophin, with slower decline in ambulatory function compared to baseline. Long-term treatment with eteplirsen leads to accumulation of dystrophin over time and observed functional benefits in patients with DMD. OBJECTIVE: Compare long-term ambulatory function in eteplirsen-treated patients versus controls. METHODS: Study 201/202 included 12 eteplirsen-treated patients assessed twice/year for ambulatory function over 4 years. Ambulatory evaluations (6-minute walk test [6MWT], loss of ambulation, and North Star Ambulatory Assessment [NSAA]) were compared with matched controls from Italian Telethon and Leuven registries. RESULTS: At Years 3 and 4, eteplirsen-treated patients demonstrated markedly greater mean 6MWT than controls (difference in change from baseline of 132 m [95%CI (29, 235), p = 0.015] at Year 3 and 159 m [95%CI (66, 253), p = 0.002] at Year 4). At Year 4, a significantly greater proportion of eteplirsen-treated patients were still ambulant versus controls (10/12 vs 3/11; p = 0.020). At Year 3, eteplirsen-treated patients demonstrated milder NSAA decline versus controls (difference in change from baseline of 2.6, 95%CI [-6, 11]), however, the difference was not statistically significant; Year 4 control NSAA data were not available. CONCLUSION: In this retrospective matched control study, eteplirsen treatment resulted in attenuation of ambulatory decline over a 4-year observation period, supporting long-term benefit in patients with DMD.

Resistance Analyses of HCV NS3/4A Protease and NS5B Polymerase from Clinical Studies of Deleobuvir and Faldaprevir.

BACKGROUND & AIM: The resistance profile of anti-hepatitis C virus (HCV) agents used in combination is important to guide optimal treatment regimens. We evaluated baseline and treatment-emergent NS3/4A and NS5B amino-acid variants among HCV genotype (GT)-1a and -1b-infected patients treated with faldaprevir (HCV protease inhibitor), deleobuvir (HCV polymerase non-nucleoside inhibitor), and ribavirin in multiple clinical studies. METHODS: HCV NS3/4A and NS5B population sequencing (Sanger method) was performed on all baseline plasma samples (n = 1425 NS3; n = 1556 NS5B) and on post-baseline plasma samples from patients with virologic failure (n = 113 GT-1a; n = 221 GT-1b). Persistence and time to loss of resistance-associated variants (RAVs) was estimated using Kaplan-Meier analysis. RESULTS: Faldaprevir RAVs (NS3 R155 and D168) and deleobuvir RAVs (NS5B 495 and 496) were rare (<1%) at baseline. Virologic response to faldaprevir/deleobuvir/ribavirin was not compromised by common baseline NS3 polymorphisms (e.g. Q80K in 17.5% of GT-1a) or by NS5B A421V, present in 20% of GT-1a. In GT-1b, alanine at NS5B codon 499 (present in 15% of baseline sequences) was associated with reduced response. Treatment-emergent RAVs consolidated previous findings: NS3 R155 and D168 were key faldaprevir RAVs; NS5B A421 and P495 were key deleobuvir RAVs. Among on-treatment virologic breakthroughs, RAVs emerged in both NS3 and NS5B (>90%). Virologic relapse was associated with RAVs in both NS3 and NS5B (53% GT-1b; 52% GT-1b); some virologic relapses had NS3 RAVs only (47% GT-1a; 17% GT-1b). Median time to loss of GT-1b NS5B P495 RAVs post-treatment (5 months) was less than that of GT-1b NS3 D168 (8.5 months) and GT-1a R155 RAVs (11.5 months). CONCLUSION: Faldaprevir and deleobuvir RAVs are more prevalent among virologic failures than at baseline. Treatment response was not compromised by common NS3 polymorphisms; however, alanine at NS5B amino acid 499 at baseline (wild-type in GT-1a, polymorphism in GT-1b) may reduce response to this deleobuvir-based regimen.

Low glomerular filtration rate, recurrent stroke risk, and effect of renin-angiotensin system modulation.

BACKGROUND AND PURPOSE: To investigate the association of low estimated glomerular filtration rate (eGFR) <60 mL/min with recurrent stroke risk and to evaluate whether add-on renin-angiotensin system modulator therapy is associated with lower recurrent stroke risk in patients with low eGFR. METHODS: We analyzed the database of a multicenter trial involving 18,666 patients with recent ischemic stroke followed for 2.5 years. Primary outcome was time to first recurrent stroke. Independent associations of low eGFR with outcome in the entire cohort and add-on telmisartan treatment with outcome among those with low eGFR were evaluated. RESULTS: Low eGFR was observed in 3630 (20.1%) patients. Patients with low eGFR were older, more likely women, with a known history of hypertension. In unadjusted analyses, patients with low eGFR were more likely to experience a recurrent stroke (hazard ratio, 1.34; 95% confidence interval, 1.20-1.49). After adjusting for confounders, low eGFR was still associated with recurrent stroke but to a lesser extent (hazard ratio, 1.16; 95% confidence interval, 1.04-1.31). Telmisartan treatment among patients with low eGFR was not independently associated with recurrent stroke (hazard ratio, 1.08; 95% confidence interval, 0.89-1.31). CONCLUSIONS: Low eGFR is independently associated with a higher risk of recurrent stroke, but short-term add-on telmisartan therapy does not seem to mitigate this risk. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT00153062.

Discontinuation of antiplatelet study medication and risk of recurrent stroke and cardiovascular events: results from the PRoFESS study.

BACKGROUND: Several case control studies have reported an increased risk of cardiovascular events following discontinuation of antiplatelet agents in high-risk patients. We therefore sought to investigate the risk of recurrent stroke and cardiovascular events following discontinuation of antiplatelet study medication in the Prevention Regimen for Effectively Avoiding Second Strokes (PRoFESS) trial, a large randomized secondary stroke prevention study. METHODS: The recurrent stroke and cardiovascular event rates following discontinuation of aspirin plus extended-release dipyridamole (ASA + ERDP) or clopidogrel were compared to the event rates in the on-treatment populations (patients who had discontinued their antiplatelet medication due to an outcome event were kept in the on-treatment population in order not to underestimate the on-treatment stroke rate). RESULTS: In 7,212 treated ASA + ERDP patients, the stroke incidence rate for the on-treatment group was 729 strokes with an average exposure of 17,048 person-years (0.12 per 1,000 person-days). For 7,864 treated clopidogrel patients, the stroke incidence rate for the on-treatment group was 737 strokes with an average exposure of 18,715 person-years (0.11 per 1,000 person-days). ASA + ERDP was discontinued in 2,843 patients (in 57.7% due to an adverse event, 28.2% noncompliance, 1.4% loss to follow-up, 4.5% withdrawal of consent and 8.1% other/nonspecified reasons) and clopidogrel was permanently discontinued in 2,176 patients (49.0% due to an adverse event, 34.2% noncompliance, 1.8% loss to follow-up, 5.3% withdrawal of consent and 9.7% other/nonspecified reasons). Within 30 days, a recurrent stroke occurred in 31 patients (0.37 per 1,000 person-days) after discontinuation of ASA + ERDP and in 15 patients (0.24 per 1,000 person-days) after discontinuation of clopidogrel. This corresponds to an absolute excess risk of 0.77% within 30 days after discontinuation of ASA + ERDP and 0.40% within 30 days after discontinuation of clopidogrel compared with the on-treatment study populations. A combined vascular endpoint (stroke, myocardial infarction, vascular death) occurred in 68 patients (0.82 per 1,000 person-days) within 30 days after discontinuation of ASA + ERDP and in 47 patients (0.75 per 1,000 person-days) within 30 days after discontinuation of clopidogrel. This corresponds to an absolute excess risk of 2.02% within 30 days after discontinuation of ASA + ERDP and 1.83% within 30 days after discontinuation of clopidogrel compared with the on-treatment study populations. CONCLUSION: Discontinuation of antiplatelet medication after ischemic stroke should be advocated only when the risk and severity of bleeding clearly outweigh the risk of cardiovascular events.

Analysis of genome-wide association data by large-scale Bayesian logistic regression.

Single-locus analysis is often used to analyze genome-wide association (GWA) data, but such analysis is subject to severe multiple comparisons adjustment. Multivariate logistic regression is proposed to fit a multi-locus model for case-control data. However, when the sample size is much smaller than the number of single-nucleotide polymorphisms (SNPs) or when correlation among SNPs is high, traditional multivariate logistic regression breaks down. To accommodate the scale of data from a GWA while controlling for collinearity and overfitting in a high dimensional predictor space, we propose a variable selection procedure using Bayesian logistic regression. We explored a connection between Bayesian regression with certain priors and L1 and L2 penalized logistic regression. After analyzing large number of SNPs simultaneously in a Bayesian regression, we selected important SNPs for further consideration. With much fewer SNPs of interest, problems of multiple comparisons and collinearity are less severe. We conducted simulation studies to examine probability of correctly selecting disease contributing SNPs and applied developed methods to analyze Genetic Analysis Workshop 16 North American Rheumatoid Arthritis Consortium data.

Armitage's trend test for genome-wide association analysis: one-sided or two-sided?

The importance of considering confounding due to population stratification in genome-wide association analysis using case-control designs has been a source of debate. Armitage's trend test, together with some other methods developed from it, can correct for population stratification to some extent. However, there is a question whether the one-sided or the two-sided alternative hypothesis is appropriate, or to put it another way, whether examining both the one-sided and the two-sided alternative hypotheses can give more information. The dataset for Problem 1 of Genetic Analysis Workshop 16 provides us with a chance to address this question. Because it is a part of a combined sample from the North American Rheumatoid Arthritis Consortium (NARAC) and the Swedish Epidemiological Investigation of Rheumatoid Arthritis (EIRA), the results from the combined sample can be used as references. To test this aim, the last 10,000 single-nucleotide polymorphisms (SNPs) on chromosome 9, which contain the common genetic variant at the TRAF1-C5 locus, were examined by conducting Armitage's trend tests. Examining the two-sided alternative hypothesis shows that SNPs rs12380341 (p = 9.7 x 10-11) and rs872863 (p = 1.7 x 10-15), along with six SNPs across the TRAF1-C5 locus, rs1953126, rs10985073, rs881375, rs3761847, rs10760130, and rs2900180 (p~1 x 10-7), are significantly associated with anti-cyclic citrullinated peptide-positive rheumatoid arthritis. But examining the one-sided alternative hypothesis that the minor allele is positively associated with the disease shows that only those six SNPs across the TRAF1-C5 locus are significantly associated with the disease (p~1 x 10-8), which is consistent with the results from the combined sample of the NARAC and the EIRA.