Zoppo, Gregory J. del

Background and Purpose— Previous studies of multiple-day dosing with the defibrinogenating agent, ancrod, in acute ischemic stroke yielded conflicting results but suggested that a brief dosing regimen might improve efficacy and safety. The Ancrod Stroke Program was designed to test this concept in subjects beginning ancrod or placebo within 6 hours of the onset of acute ischemic stroke. Methods— Five hundred subjects with acute ischemic stroke who could begin receiving study material within 6 hours of symptom onset were infused intravenously with either ancrod (0.167 IU/kg per hour) or placebo over 2 or 3 hours. The primary efficacy outcome was a dichotomized, modified Rankin score at 90 days with less stringent cut-points for higher prestroke modified Rankin score and pretreatment NIHSS total score (“responder analysis”). Safety variables included mortality, major bleeding, and intracranial hemorrhage. Results— Although the desired changes in fibrinogen level were seen in >90% of ancrod subjects, interim analysis for futility led to the study being halted for lack of efficacy. Positive responder status in the interim dataset was seen in 39.6% of ancrod subjects and 37.2% of placebo subjects ( P =0.47). Ninety-day mortality did not differ between the 2 groups (ancrod, 15.6%; placebo, 14.1%; P =0.32), and the incidence of symptomatic intracranial hemorrhage within the first 72 hours, although not significantly different in ancrod compared to placebo subjects ( P =0.19), was approximately twice as high (3.9% vs 2.0%; P =0.19). Conclusion— These results demonstrate that intravenous ancrod starting within 6 hours after symptom onset in a broad selection of subjects with ischemic stroke did not improve their outcome and revealed a trend to increased bleeding despite successful efforts to achieve rapid initial defibrinogenation and avoid prolonged hypofibrinogenemia.

Background and Purpose— Epidemiological studies have found strong correlations between elevated plasma fibrinogen levels and both ischemic stroke incidence and stroke mortality. Little is known about the influence of fibrinogen levels on functional stroke outcome. Methods— Placebo data from the Stroke Treatment with Ancrod Trial (STAT) and European Stroke Treatment with Ancrod Trial (ESTAT) were analyzed. Fibrinogen levels were determined within 3 hours (STAT) or 6 hours (ESTAT) of stroke onset and at preset intervals throughout 5 days of intravenous infusions. Barthel Index scores at 90 days quantified functional outcomes. The association between initial fibrinogen levels and functional outcomes was evaluated using a multiple logistic regression analysis. Results— Fibrinogen levels increased gradually over the first 24 hours from a pretreatment median value of 340 mg/dL to a 24-hour median value of 376 mg/dL. In a univariate analysis, the proportion of patients with good functional outcome decreased with increasing quartiles of initial fibrinogen levels in both STAT (36.0% to 26.2%) and ESTAT (53.8% to 24.8%). In a multifactorial analysis, the same trend was observed. Patients with initial fibrinogen levels <450 mg/dL had better outcomes in both studies; the difference (42.0% versus 21.6%) was significant in ESTAT ( P =0.0006), even when corrected for age and initial stroke severity. Conclusion— The independent association of higher initial fibrinogen levels with poor outcome needs to be verified using a larger acute stroke dataset. Even in the present small populations, the apparent association of these 2 variables suggests that treatments designed to reduce fibrinogen levels could potentially be important in treating acute ischemic stroke.