An abbreviated phase 2b trial
The CHOICE trial was conducted in seven centers in Catalonia, Spain.
For the study, patients with large vessel occlusion acute ischemic stroke treated with thrombectomy within 24 hours after stroke onset and who had achieved successful reperfusion (an expanded TICI angiographic score of 2b50 to 3) were randomly assigned to receive intra-arterial alteplase (0.225 mg/kg; maximum dose, 22.5 mg) infused over 15 to 30 minutes or placebo.
Because of the lack of continued availability of placebo supplies, the study had to be stopped early after 121 patients were enrolled (65 alteplase; 56 placebo), and after a few dropouts who did not receive treatment, the analysis was performed on 61 patients who received alteplase and 52 given placebo.
Results showed that the proportion of patients with an mRS score of 0 or 1 at 90 days was 59% (36/61) with alteplase and 40.4% (21/52) with placebo (adjusted risk difference, 18.4%; 95% confidence interval, 0.3%-36.4%; P = .047).
The proportion of patients with symptomatic intracranial hemorrhage within 24 hours was 0% with alteplase and 3.8% with placebo (risk difference, −3.8%; 95% CI, −13.2% to 2.5%).
Mortality at 90 days was 8% with alteplase and 15% with placebo (risk difference, −7.2%; 95% CI, −19.2% to 4.8%).
The improved clinical outcomes in the alteplase group were seen despite only minor differences between the treatment groups in angiographic scores or in other surrogate imaging, Dr. Chamorro pointed out, suggesting that the improved functional outcome may be explained by an amelioration in the microcirculatory reperfusion.
He said the study also supported the safety of intra-arterial alteplase infusion for 15-30 minutes at the dose used. Of note, 60% of the study population had also received IV alteplase before thrombectomy.
In the JAMA study, the authors report that current guidelines recommend that all eligible patients receive intravenous alteplase before thrombectomy, and the results of this trial do not contradict this recommendation.
“The study results support the safety of adjunct intra-arterial alteplase in patients with successful reperfusion at the end of thrombectomy, including in patients treated previously with intravenous alteplase, although the findings on effectiveness should be interpreted as preliminary, requiring replication before any recommendations for practice change,” they concluded.
Dr. Chamorro said that his group was now planning a second larger trial, CHOICE-2.
In an accompanying editorial in JAMA, Pooja Khatri, MD, MSc, University of Cincinnati, said “the 18% treatment effect observed in this 113-patient trial is remarkable.”
However, she cautions that consideration of its clinical implications must be tempered because of the lack of precision of the effect estimate, given wide 95% confidence intervals, the small sample size, and the observation that trials with early termination are well known to overestimate treatment effect.
But she acknowledges that the results suggest “that additional reperfusion therapy may be warranted after relatively successful mechanical thrombectomy of large vessel occlusions, whether to treat the residual primary thrombus, more distal arterial occlusions, or perhaps even microthromboses.”
Dr. Khatri noted that this approach runs counter to the recent movement to consider bypass of intravenous alteplase altogether in thrombectomy-eligible patients and suggests that additional or perhaps more targeted thrombolysis will be the most beneficial approach.
Further studies testing current thrombolytic agents, novel clot-dissolving agents, and other adjunctive antithrombotic and anti-inflammatory agents are needed, she concluded.
A version of this article first appeared on Medscape.com.