Comparative study of on-label versus off-label treatment of intracranial aneurysms with the Pipeline embolization device

OBJECTIVE The Pipeline embolization device ( PED) is widely used for the treatment of intracranial aneurysms, including in off- label applications. In this work, the authors compared the real-world efficacy and safety of PED use in on-label and off-label aneurysm treatments. METHODS Clinical and angiographic data of patients who underwent PED placement at a high-volume academic medical center were retrospectively obtained. Treatments were classified as on-label if they fell within the applications approved by the United States Food and Drug Administration as of 2021. Recorded outcomes included aneurysm occlusion, procedural complications, ischemic events, in-stent stenosis, intracranial hemorrhage, postprocedural functional status, and death. RESULTS In total, 416 aneurysms in 330 patients were treated with PED, comprising 256 aneurysms that received onlabel treatments and 160 that received off- label treatments. The overall rate of complete aneurysm occlusion was 76.4% for on-label aneurysms and 75.6% for off-label aneurysms (p = 0.898). The risk of ischemic stroke in patients who underwent off-label treatments was 15.2%, which was higher than the 4.2% rate in patients who underwent on-label treatment (p = 0.003). All other clinical complications, procedural complications, and long- term functional status were comparable between the on-label and off- label groups. CONCLUSIONS In real-world practice, off- label use of PED is common and can achieve similar efficacy as on-label use. However, in aggregate, off-label use was found to carry an increased rate of ischemic complications. With judicious attention to safety and individual patient characteristics, these results highlight the scale and general feasibility of offlabel PED use by experts.