In combination with reteplase, however, abciximab appears to provide both acceptable safety and efficacy, said Dr. Warach, who is Section Chief of Stroke Diagnostics and Therapeutics, National Institute of Neurological Disorders and Stroke (NINDS), Bethesda, Maryland, United States.

Dr. Warach and co-investigators conducted this open-label trial to evaluate abciximab as monotherapy or in combination with reteplase to determine whether there was an acceptable combination of the two drugs. They wanted to address a key limitation of tissue plasminogen activator (tPA), which must be given within 3 hours of the onset of symptoms.

Their ReoPro Retavase Reperfusion of Stroke Safety Study -- Imaging Evaluation (ROSIE) trial enrolled patients who were 18 to 80 years old and had had a disabling ischemic stroke 3 to 24 hours before enrollment. Subjects had a National Institute of Health Stroke Severity (NIHSS) score of no more than 16, had detectable perfusion on a magnetic resonance imaging (MRI) study, and a negative MRI for acute or chronic intracranial hemorrhage.

All 34 patients received intravenous abciximab at a dose of 0.25 mg/kg for an initial bolus followed by 0.125 mcg/kg/minute for 12 hours. They were then assigned to receive one of the following doses of reteplase: 0, 2.5 U, 5 U, 7.5 U, or 10 U.

Doses were assigned to successive cohorts of three patients based on whether the previous dose was associated with toxicity, response, or neither. Toxicity was defined as symptomatic intracranial hemorrhage on computed tomography or a major systemic hemorrhage within 48 hours of treatment. A response was defined as a complete reperfusion as seen on MRI within 24 hours of initiating therapy and the absence of toxicity.

The investigators defined the acceptability of a dose as a maximum toxicity rate of 10% and a minimum response rate of 50%. A blinded radiologist determined whether reperfusion and intracranial hemorrhage had occurred. An untreated historical control group of 19 patients had no toxicity and a reperfusion rate of 16%.

Among the patients in the current research, 6% had toxicities, consisting of one intracranial hemorrhage and one gastrointestinal hemorrhage, neither of which was fatal, and both occurred in the group on 7.5 mg of reteplase. Among the patients overall, 29% had complete reperfusion within 24 hours.

Response rates were 33% in the abciximab monotherapy group, 40% in the three on 2.5 U of reteplase, 45% for those on 5 U, 58% for those on 7.5 U, and 50% for those on 10 U.

The findings showed that abciximab combined with reteplase "merits continued investigation as a promising stroke therapy," said Dr. Warach.


[Presentation title: ReoPro Retavase Reperfusion of Stroke Safety Study -- Imaging Evaluation (ROSIE). Abstract LB1]

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