Andrew P. Grieve

Acute Stroke Therapy by Inhibition of Neutrophils (ASTIN): An Adaptive Dose-Response Study of UK-279,276 in Acute Ischemic Stroke

Background and Purpose— UK-279,276 (neutrophil inhibitory factor) reduced infarct volume in a rat middle cerebral artery occlusion reperfusion model. ASTIN (Acute Stroke Therapy by Inhibition of Neutrophils) was an adaptive phase 2 dose-response–finding, proof-of-concept study to establish whether UK-279,276 improves recovery in acute ischemic stroke. The prime objective was to determine the dose that gave a clinically relevant effect in patients. Methods— A Bayesian sequential design with real-time efficacy data capture and continuous reassessment of the dose response allowed double-blind, randomized, adaptive allocation to 1 of 15 doses (dose range, 10 to 120 mg) or placebo and early termination for efficacy or futility. The primary end point was change from baseline to day 90 on the Scandinavian Stroke Scale (&Dgr;SSS), adjusted for baseline SSS, aiming for a 3-point additional mean recovery above placebo. Results— Nine hundred sixty-six acute stroke patients (887 ischemic, 204 cotreated with intravenous tissue plasminogen activator; mean baseline SSS score, 28; range, 10 to 40) were treated within 6 hours of symptom onset. Mean &Dgr;SSS was approximately +17 points of improvement on SSS for the overall evaluable population. There was no treatment effect for UK-279,276 (posterior probability of futility, 0.89). The trial was stopped early for futility. Post hoc analysis indicated a mean 1.6-point additional improvement on &Dgr;SSS in the tissue plasminogen activator–treated subset (credible interval=0.5, 2.6). UK-279,276 was generally well tolerated, with no increased incidence of infections. Conclusions— UK-279,276 did not improve recovery in acute ischemic stroke patients but was devoid of serious side effects. The adaptive design facilitated early termination for futility.

Risk and Cumulative Risk of Stroke Recurrence A Systematic Review and Meta-Analysis

Background and Purpose— Estimates of risk of stroke recurrence are widely variable and focused on the short- term. A systematic review and meta-analysis was conducted to estimate the pooled cumulative risk of stroke recurrence. Methods— Studies reporting cumulative risk of recurrence after first-ever stroke were identified using electronic databases and by manually searching relevant journals and conference abstracts. Overall cumulative risks of stroke recurrence at 30 days and 1, 5, and 10 years after first stroke were calculated, and analyses for heterogeneity were conducted. A Weibull model was fitted to the risk of stroke recurrence of the individual studies and pooled estimates were calculated with 95% CI. Results— Sixteen studies were identified, of which 13 studies reported cumulative risk of stroke recurrence in 9115 survivors. The pooled cumulative risk was 3.1% (95% CI, 1.7–4.4) at 30 days, 11.1% (95% CI, 9.0–13.3) at 1 year, 26.4% (95% CI, 20.1–32.8) at 5 years, and 39.2% (95% CI, 27.2–51.2) at 10 years after initial stroke. Substantial heterogeneity was found at all time points. This study also demonstrates a temporal reduction in 5-year risk of stroke recurrence from 32% to 16.2% across the studies. Conclusions— The cumulative risk of recurrence varies greatly up to 10 years. This may be explained by differences in case mix and changes in secondary prevention over time However, methodological differences are likely to play an important role and consensus on definitions would improve future comparability of estimates and characterization of groups of stroke survivors at increased risk of recurrence.

Ethnic group disparities in 10-year trends in stroke incidence and vascular risk factors the South London Stroke Register (SLSR)

Background and Purpose— Data monitoring trends in stroke risk among different ethnic groups are lacking. Thus, we investigated trends in stroke incidence and modifiable stroke risk factors over a 10-year time period between different ethnic groups. Methods— Changes in stroke incidence were investigated with the South London Stroke Register (SLSR). The SLSR is a population-based stroke register, covering a multiethnic population of 271 817 inhabitants in South London with 63% white, 28% black, and 9% of other ethnic group (2001 Census). Results— Between 1995 and 2004, 2874 patients with first-ever stroke of all age groups were included. Total stroke incidence decreased over the 10-year study period in men (incidence rate ratio 1995 to 1996 versus 2003 to 2004 [IRR] 0.82, 95% CI 0.69 to 0.97) and in women (IRR 0.76, 95% CI 0.64 to 0.90). A similar decline in total stroke incidence could be observed in whites for men and women (IRR 0.76, 95% CI 0.62 to 0.93 versus IRR 0.73, 95% CI 0.59 to 0.89, respectively); in blacks, total stroke incidence was reducing only in women (IRR 0.48, 95% CI 0.31 to 0.75). In whites, the prevalence of prior-to-stroke hypertension (P=0.0017), atrial fibrillation (P=0.0113), and smoking (P=0.0177) decreased; no statistically significant changes in prior-to-stroke risk factors were observed in blacks. Total stroke incidence was higher in blacks compared to whites (IRR 1.27, 95% CI 1.10 to 1.46 in men; IRR 1.29, 95% CI 1.11 to 1.50 in women), but the black-white gap reduced during the 10-year time period (IRR 1.43, 95% CI 1.13 to 1.82 in 1995 to 1996 to 1.18, 95% CI 0.93 to 1.49 in 2003 to 2004). Conclusions— Stroke incidence decreased over a 10-year time period. The greatest decline in incidence was observed in black women, but ethnic group disparities still exist, indicating a higher stroke risk in black people compared to white people. Advances in risk factor reduction observed in the white population were failed transferring to the black population.

Estimates of Outcomes Up to Ten Years after Stroke: Analysis from the Prospective South London Stroke Register

Charles Wolfe and colleagues collected data from the South London Stroke Register on 3,373 first strokes registered between 1995 and 2006 and showed that between 20% and 30% of survivors have poor outcomes up to 10 years after stroke.

Adaptive Bayesian Designs for Dose-Ranging Drug Trials

In the standard type of phase II efficacy trial, patients are assigned to a dose from among those being considered (usually 4 to 12 in number). Assignment is random, usually with equal numbers of patients assigned to each dose. Based on the results of the trial, a decision is made to either enter phase III in the drug’s development, stop the drug’s development, or conduct another phase II trial. Such a design is inefficient, in terms of both time and resources. We have developed an innovative class of designs that we are introducing into practice. In this case study we describe the designs, address difficulties in implementing them in actual clinical trials, and relay our experience with using them.

Frequency and predictors for the risk of stroke recurrence up to 10 years after stroke: the South London Stroke Register

Background: Data estimating the risk of, and predictors for, long-term stroke recurrence are lacking. Methods: Data were collected from the population-based South London Stroke Register. Patients were followed up for a maximum of 10 years. Kaplan–Meier estimates and Cox proportional hazards models were used to assess the cumulative risk of and predictors for first stroke recurrence. Variables analysed included sociodemographic factors, stroke subtype (defined as cerebral infarction, intracerebral haemorrhage and subarachnoid haemorrhage), stroke severity markers and prior-to-stroke risk factors. Results: Between 1995 and 2004, 2874 patients with first-ever stroke were included. The mean follow-up period was 2.9 years. During 8311 person-years of follow-up, 303 recurrent events occurred. The cumulative risk of stroke recurrence at 1 year, 5 years and 10 years was 7.1%, 16.2% and 24.5% respectively. No differences in stroke recurrence were noted between the stroke subtypes. Factors increasing the risk of recurrence at 1 year were previous myocardial infarction (HR 1.73; 95% CI 1.08 to 2.78) and atrial fibrillation (HR 1.61; 95% CI 1.04 to 4.27); at 5 years, hypertension (HR 1.47; 95% CI 1.08 to 1.99) and atrial fibrillation (HR 1.79; 95% CI 1.29 to 2.49); and at 10 years, older age (p = 0.04), and hypertension (HR 1.38, 95% CI 1.04 to 1.82), myocardial infarction (HR 1.50, 95% CI 1.06 to 2.11) and atrial fibrillation (HR 1.51, 95% CI 1.09 to 2.09). Conclusions: Very-long-term risk of stroke recurrence is substantial. Different predictors for stroke recurrence were identified throughout the follow-up period. Risk factors prior to initial stroke have a significant role in predicting stroke recurrence up to 10 years.

A dual-centre, cohort comparison of open, laparoscopic and robotic-assisted radical cystectomy

Introduction:  The role of minimally invasive radical cystectomy as opposed to open surgery for bladder cancer is not yet established. We present comparative outcomes of open, laparoscopic and robotic‐assisted radical cystectomy

ASTIN: a Bayesian adaptive dose–response trial in acute stroke:

Understanding the dose–response is critical for successful drug development. We describe an adaptive design to efficiently learn about the dose–response and the ED95. A dynamic termination rule allows for early discontinuation either for efficacy or futility. The design was deployed in ASTIN, a phase II proof-of-concept trial of the neuroprotectant, neutrophil inhibitory factor (NIF), in acute stroke. We discuss the learning from this trial.

The association of post-stroke neurological improvement with risk of subsequent deterioration due to stroke events.

We sought to simultaneously confirm that substantial recovery at day 1 and day 7 after acute ischaemic stroke onset is associated with subsequent neurological deterioration in patients of the Acute Stroke Therapy by Inhibition of Neutrophils randomized clinical trial. Substantial recovery was assessed by improvement in the National Institutes of Health Stroke Score (NIHSS). Neurological deterioration was defined as any stroke event or NIHSS worsening from recovery assessment to day 90. After adjusting for age, t‐PA and day 1 NIHSS, there was a non‐significant tendency of substantial (pre‐specified as 75%) recovery at day 1 to be associated with later deterioration [odds ratio (OR) 2.47; 95% CI, 0.95–6.50]. The corresponding OR for substantial (pre‐defined as 65%) recovery at day 7 was 1.84 (0.85–3.96). Other thresholds for recovery were significantly associated with later deterioration: >50%, 80%, 90% and 100% for day 1 and >50%, 60%, 70%, 90% and 100% for day 7. The effect of recovery at day 1 was more important than that of later recovery. This study confirms the association between recovery and subsequent neurological deterioration and is the first to indicate the greater importance of acute recovery at day 1 in comparison with later recovery.

Adaptive Designs in Clinical Drug Development: Opportunities, Challenges, and Scope Reflections Following PhRMA's November 2006 Workshop

This paper provides reflections on the opportunities, scope and challenges of adaptive design as discussed at PhRMAs workshop held in November 2006. We also provide a status report of workstreams within PhRMAs working group on adaptive designs, which were triggered by the November workshop. Rather than providing a comprehensive review of the presentations given, we limit ourselves to a selection of key statements. The authors reflect the position of PhRMAs working group on adaptive designs.