Loren Shen

The Argatroban and Tissue-Type Plasminogen Activator Stroke Study Final Results of a Pilot Safety Study

Background and Purpose— Argatroban is a direct thrombin inhibitor that safely augments recanalization achieved by tissue-type plasminogen activator (tPA) in animal stroke models. The Argatroban tPA Stroke Study was an open-label, pilot safety study of tPA plus Argatroban in patients with ischemic stroke due to proximal intracranial occlusion. Methods— During standard-dose intravenous tPA, a 100-&mgr;g/kg bolus of Argatroban and infusion for 48 hours was adjusted to a target partial thromboplastin time of 1.75× baseline. The primary outcome was incidence of significant intracerebral hemorrhage defined as either symptomatic intracerebral hemorrhage or Parenchymal Hematoma Type 2. Recanalization was measured at 2 and 24 hours by transcranial Doppler or CT angiography. Results— Sixty-five patients were enrolled (45% men, mean age 63±14 years, median National Institutes of Health Stroke Scale=13). The median (interquartile range) time tPA to Argatroban bolus was 51 (38–60) minutes. Target anticoagulation was reached at a median (interquartile range) of 3 (2–7) hours. Significant intracerebral hemorrhage occurred in 4 patients (6.2%; 95% CI, 1.7–15.0). Of these, 3 were symptomatic (4.6%; 95% CI, 0.9–12.9). Seven patients (10%) died in the first 7 days. Within the 2-hour monitoring period, transcranial Doppler recanalization (n=47) occurred in 29 (61%) patients: complete in 19 (40%) and partial in another 10 (21%). Conclusions— The combination of Argatroban and intravenous tPA is potentially safe in patients with moderate neurological deficits due to proximal intracranial arterial occlusions and may produce more complete recanalization than tPA alone. Continued evaluation of this treatment combination is warranted. Clinical Trial Registration— URL: www.clinicaltrials.gov. Unique identifier: NCT00268762.

Design of a prospective, dose-escalation study evaluating the Safety of Pioglitazone for Hematoma Resolution in Intracerebral Hemorrhage (SHRINC).

Rationale Preclinical work demonstrates that the transcription factor peroxisome proliferator-activated receptor gamma plays an important role in augmenting phagocytosis while modulating oxidative stress and inflammation. We propose that targeted stimulation of phagocytosis to promote efficient removal of the hematoma without harming surrounding brain cells may be a therapeutic option for intracerebral hemorrhage. Aims The primary objective is to assess the safety of the peroxisome proliferator-activated receptor gamma agonist, pioglitazone, in increasing doses for three-days followed by a maintenance dose, when administered to patients with spontaneous intracerebral hemorrhage within 24 h of symptom onset compared with standard care. We will determine the maximum tolerated dose of pioglitazone. Study Design This is a prospective, randomized, blinded, placebo-controlled, dose-escalation safety trial in which patients with spontaneous intracerebral hemorrhage are randomly allocated to placebo or treatment. The Continual Reassessment Method for dose finding is used to determine the maximum tolerated dose of pioglitazone. Hematoma and edema resolution is evaluated with serial magnetic resonance imaging (MRI) at specified time points. Functional outcome will be evaluated at three- and six-months. Outcomes The primary safety outcome is mortality at discharge. Secondary safety outcomes include mortality at three-months and six-months, symptomatic cerebral edema, clinically significant congestive heart failure, edema, hypoglycemia, anemia, and hepatotoxicity. Radiographic outcomes will explore the time frame for resolution of 25%, 50%, and 75% of the hematoma. Clinical outcomes are measured by the National Institutes of Health Stroke Scale (NIHSS), the Barthel Index, modified Rankin Scale, Stroke Impact Scale-16, and EuroQol at three- and six-months.

CLOTBUST-Hands Free Pilot Safety Study of a Novel Operator-Independent Ultrasound Device in Patients With Acute Ischemic Stroke

Background and Purpose— The Combined Lysis of Thrombus in Brain Ischemia With Transcranial Ultrasound and Systemic T-PA-Hands-Free (CLOTBUST-HF) study is a first-in-human, National Institutes of Health–sponsored, multicenter, open-label, pilot safety trial of tissue-type plasminogen activator (tPA) plus a novel operator-independent ultrasound device in patients with ischemic stroke caused by proximal intracranial occlusion. Methods— All patients received standard-dose intravenous tPA, and shortly after tPA bolus, the CLOTBUST-HF device delivered 2-hour therapeutic exposure to 2-MHz pulsed-wave ultrasound. Primary outcome was occurrence of symptomatic intracerebral hemorrhage. All patients underwent pretreatment and post-treatment transcranial Doppler ultrasound or CT angiography. National Institutes of Health Stroke Scale scores were collected at 2 hours and modified Rankin scale at 90 days. Results— Summary characteristics of all 20 enrolled patients were 60% men, mean age of 63 (SD=14) years, and median National Institutes of Health Stroke Scale of 15. Sites of pretreatment occlusion were as follows: 14 of 20 (70%) middle cerebral artery, 3 of 20 (15%) terminal internal carotid artery, and 3 of 20 (15%) vertebral artery. The median (interquartile range) time to tPA at the beginning of sonothrombolysis was 22 (13.5–29.0) minutes. All patients tolerated the entire 2 hours of insonation, and none developed symptomatic intracerebral hemorrhage. No serious adverse events were related to the study device. Rates of 2-hour recanalization were as follows: 8 of 20 (40%; 95% confidence interval, 19%–64%) complete and 2 of 20 (10%; 95% confidence interval, 1%–32%) partial. Middle cerebral artery occlusions demonstrated the greatest complete recanalization rate: 8 of 14 (57%; 95% confidence interval, 29%–82%). At 90 days, 5 of 20 (25%, 95% confidence interval, 7%–49) patients had a modified Rankin scale of 0 to 1. Conclusions— Sonothrombolysis using a novel, operator-independent device, in combination with systemic tPA, seems safe, and recanalization rates warrant evaluation in a phase III efficacy trial. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: CLOTBUST-HF NCT01240356.

CLOTBUST-Hands Free Initial Safety Testing of a Novel Operator-Independent Ultrasound Device in Stroke-Free Volunteers

Background and Purpose— We aimed to evaluate safety and tolerability of a novel operator-independent ultrasound device among stroke-free volunteers. Methods— A headframe containing 18 ultrasound transducers (each operating at 2 MHz, pulsed-wave) was used to expose both temporal windows and the suboccipital window. The transmission characteristics were set to emulate the acoustic characteristics of the exposure levels in the Combined Lysis of Thrombus in Brain Ischemia using Transcranial Ultrasound and Systemic tPA (CLOTBUST) trial and to never exceed Food and Drug Administration mandated diagnostic ultrasound exposure limits. Volunteers underwent 2 hours of insonation with transducer activation one at a time. Safety was captured using serial neurological examinations and pre- and postinsonation MRI for detection of the blood brain barrier permeability. Results— A total of 15 volunteers (40% men; 49±16 years; 27% black; all pre-exposure National Institutes of Health Stroke Scale scores 0) were enrolled. Five volunteers received pulsed-wave ultrasound via the best pair temporal transducers, 5 via sequential activation of the suboccipital transducers, and 5 via sequential activation of all bilateral temporal and suboccipital transducers. All subjects were safely insonated with no adverse effects as indicated by the neurological examinations during, immediately after the exposure, and at 24 hours, and no abnormality of the blood brain barrier was found on any of the MRIs. Conclusions— Our novel device was well tolerated by stroke-free volunteers and did not cause any neurological dysfunction nor did it affect blood brain barrier integrity. The safety and efficacy of the device are now being tested in stroke patients receiving intravenous tissue-type plasminogen activator in phase II–III clinical trials.

Randomized, Multicenter Trial of ARTSS-2 (Argatroban With Recombinant Tissue Plasminogen Activator for Acute Stroke)

Background and Purpose— We conducted a randomized exploratory study to assess safety and the probability of a favorable outcome with adjunctive argatroban, a direct thrombin-inhibitor, administered to recombinant tissue-type plasminogen activator (r-tPA)–treated ischemic stroke patients. Methods— Patients treated with standard-dose r-tPA, not receiving endovascular therapy, were randomized to receive no argatroban or argatroban (100 &mgr;g/kg bolus) followed by infusion of either 1 (low dose) or 3 &mgr;g/kg per minute (high dose) for 48 hours. Safety was incidence of symptomatic intracerebral hemorrhage. Probability of clinical benefit (modified Rankin Scale score 0–1 at 90 days) was estimated using a conservative Bayesian Poisson model (neutral prior probability centered at relative risk, 1.0 and 95% prior intervals, 0.33–3.0). Results— Ninety patients were randomized: 29 to r-tPA alone, 30 to r-tPA+low-dose argatroban, and 31 to r-tPA+high-dose argatroban. Rates of symptomatic intracerebral hemorrhage were similar among control, low-dose, and high-dose arms: 3/29 (10%), 4/30 (13%), and 2/31 (7%), respectively. At 90 days, 6 (21%) r-tPA alone, 9 (30%) low-dose, and 10 (32%) high-dose patients were with modified Rankin Scale score 0 to 1. The relative risks (95% credible interval) for modified Rankin Scale score 0 to 1 with low, high, and either low or high dose argatroban were 1.17 (0.57–2.37), 1.27 (0.63–2.53), and 1.34 (0.68–2.76), respectively. The probability that adjunctive argatroban was superior to r-tPA alone was 67%, 74%, and 79% for low, high, and low or high dose, respectively. Conclusions— In patients treated with r-tPA, adjunctive argatroban was not associated with increased risk of symptomatic intracerebral hemorrhage and provides evidence that a definitive effectiveness trial is indicated. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique Identifier: NCT01464788.

Methodological issues for designing and conducting a multicenter, international clinical trial in Acute Stroke: Experience from ARTSS-2 trial

BACKGROUND We describe innovations in the study design and the efficient data coordination of a randomized multicenter trial of Argatroban in Combination with Recombinant Tissue Plasminogen Activator for Acute Stroke (ARTSS-2). METHODS ARTSS-2 is a 3-arm, multisite/multiregional randomized controlled trials (RCTs) of two doses of Argatroban injection (low, high) in combination with recombinant tissue plasminogen activator (rt-PA) in acute ischemic stroke patients and rt-PA alone. We developed a covariate adaptive randomization program that balanced the study arms with respect to study site as well as hemorrhage after thrombolysis (HAT) score and presence of distal internal carotid artery occlusion (DICAO). We used simulation studies to validate performance of the randomization program before making any adaptations during the trial. For the first 90 patients enrolled in ARTSS-2, we evaluated performance of our randomization program using chi-square tests of homogeneity or extended Fishers exact test. We also designed a four-step partly Bayesian safety stopping rule for low and high dose Argatroban arms. RESULTS Homogeneity of the study arms was confirmed with respect to distribution of study site (UK sites vs. US sites, P=0.98), HAT score (0-2 vs. 3-5, P=1.0), and DICAO (N/A vs. No vs. Yes, P=0.97). Our stopping thresholds for safety of low and high dose Argatroban were not crossed. Despite challenges, data quality was assured. CONCLUSIONS We recommend adaptive designs for randomization and Bayesian safety stopping rules for multisite Phase I/II RCTs for maintaining additional flexibility. Efficient data coordination could lead to improved data quality.

Telemedicine-guided remote enrollment of patients into an acute stroke trial

Enrollment into acute stroke clinical trials is limited to experienced tertiary centers with emergency research infrastructure. Feasibility of remote enrollment via telemedicine into an acute thrombolytic clinical trial has never been demonstrated.

The Argatroban and tPA Stroke Study: final results of a pilot safety study

Background and Purpose— Argatroban is a direct thrombin inhibitor that safely augments recanalization achieved by tissue-type plasminogen activator (tPA) in animal stroke models. The Argatroban tPA Stroke Study was an open-label, pilot safety study of tPA plus Argatroban in patients with ischemic stroke due to proximal intracranial occlusion. Methods— During standard-dose intravenous tPA, a 100-&mgr;g/kg bolus of Argatroban and infusion for 48 hours was adjusted to a target partial thromboplastin time of 1.75× baseline. The primary outcome was incidence of significant intracerebral hemorrhage defined as either symptomatic intracerebral hemorrhage or Parenchymal Hematoma Type 2. Recanalization was measured at 2 and 24 hours by transcranial Doppler or CT angiography. Results— Sixty-five patients were enrolled (45% men, mean age 63±14 years, median National Institutes of Health Stroke Scale=13). The median (interquartile range) time tPA to Argatroban bolus was 51 (38–60) minutes. Target anticoagulation was reached at a median (interquartile range) of 3 (2–7) hours. Significant intracerebral hemorrhage occurred in 4 patients (6.2%; 95% CI, 1.7–15.0). Of these, 3 were symptomatic (4.6%; 95% CI, 0.9–12.9). Seven patients (10%) died in the first 7 days. Within the 2-hour monitoring period, transcranial Doppler recanalization (n=47) occurred in 29 (61%) patients: complete in 19 (40%) and partial in another 10 (21%). Conclusions— The combination of Argatroban and intravenous tPA is potentially safe in patients with moderate neurological deficits due to proximal intracranial arterial occlusions and may produce more complete recanalization than tPA alone. Continued evaluation of this treatment combination is warranted. Clinical Trial Registration— URL: www.clinicaltrials.gov. Unique identifier: NCT00268762.

Comparison Between a Standardized Questionnaire and Expert Clinicians for Capacity Assessment in Stroke Clinical Trials

Research into treatments for acute strokes has dramatically increased in the last decade. Accordingly, the need for testing through randomized clinical trials has also increased. Because of the unique combination of factors that are common in acute stroke–related research, including narrow treatment windows, ethical concerns regarding research with acute stroke populations, and capacity for informed consent, stroke clinical trial enrollment levels have remained stagnant. Given the devastating consequences of acute stroke, researchers are intensifying their efforts to recruit and enroll larger sample sizes in clinical trials.1 Capacity to consent to medical treatment or medical research is closely related to cognitive functioning, which is frequently impaired in stroke.2 Medical decision-making capacity (MDC) requires the ability to understand and appreciate diagnostic, treatment, and research information and risks and ability to express a choice that is based on adequate reasoning. The treating physician is responsible for the assessment of a patient’s decision-making capacity and clinically estimate their patient’s ability to provide informed consent.3 Many physicians request additional consultative assistance to assess cognitive capacity for consent from psychiatry or neuropsychology, which are considered to be the clinical gold standards4 or they perform standardized capacity questionnaires to aid the assessment of capacity.5,6 One such tool, the aid-to-capacity evaluation (ACE) had 80% to 89% agreement with expert clinicians in 1 study and inter-rater reliability reported as ĸ=0.79 for medical hospitalized patients.7,8 The ACE has been validated and found to be one of the best available instruments to assist clinicians in making judgments on MDC.4 It is designed to be used by trained nonclinicians and takes ≈10 minutes to perform.4 For patients who lack capacity medical decisions are deferred to a surrogate decision maker. Surrogate decision makers in acute stroke are able to accurately predict …

The Argatroban and Tissue-Type Plasminogen Activator Stroke Study

Background and Purpose— Argatroban is a direct thrombin inhibitor that safely augments recanalization achieved by tissue-type plasminogen activator (tPA) in animal stroke models. The Argatroban tPA Stroke Study was an open-label, pilot safety study of tPA plus Argatroban in patients with ischemic stroke due to proximal intracranial occlusion. Methods— During standard-dose intravenous tPA, a 100-&mgr;g/kg bolus of Argatroban and infusion for 48 hours was adjusted to a target partial thromboplastin time of 1.75× baseline. The primary outcome was incidence of significant intracerebral hemorrhage defined as either symptomatic intracerebral hemorrhage or Parenchymal Hematoma Type 2. Recanalization was measured at 2 and 24 hours by transcranial Doppler or CT angiography. Results— Sixty-five patients were enrolled (45% men, mean age 63±14 years, median National Institutes of Health Stroke Scale=13). The median (interquartile range) time tPA to Argatroban bolus was 51 (38–60) minutes. Target anticoagulation was reached at a median (interquartile range) of 3 (2–7) hours. Significant intracerebral hemorrhage occurred in 4 patients (6.2%; 95% CI, 1.7–15.0). Of these, 3 were symptomatic (4.6%; 95% CI, 0.9–12.9). Seven patients (10%) died in the first 7 days. Within the 2-hour monitoring period, transcranial Doppler recanalization (n=47) occurred in 29 (61%) patients: complete in 19 (40%) and partial in another 10 (21%). Conclusions— The combination of Argatroban and intravenous tPA is potentially safe in patients with moderate neurological deficits due to proximal intracranial arterial occlusions and may produce more complete recanalization than tPA alone. Continued evaluation of this treatment combination is warranted. Clinical Trial Registration— URL: www.clinicaltrials.gov. Unique identifier: NCT00268762.