iRhythm Technologies Announces GUARD-AF Study Results Page 1

• Results of the GUARD-AF study presented at the European Society of Cardiology (ESC) Congress 2024
• Using iRhythm’s Zio patch-based long-term continuous monitoring (LTCM), GUARD-AF is the largest randomized trial in a primary care setting to evaluate the impact of screening for undiagnosed atrial fibrillation (AF)
• Screening with Zio from iRhythm XT¹ LTCM led to an increase in new diagnoses of AF (5.0% versus 3.3%) over a mean follow-up of 15 months.
• There is no difference between hospital admission for stroke and usual care in the context of reduced statistical power due to truncated enrollment and follow-up.

SAN FRANCISCO, Sept. 1, 2024 (GLOBE NEWSWIRE) — iRhythm Technologies, Inc. (NASDAQ:IRTC), a leading digital health company focused on creating trusted solutions that detect, predict and prevent disease, today announced the presentation and publication of the GUARD-AF (ReducinG stroke by screening for IndiAgnosticized onRial fibrillation in the elderlyDividuals) randomized clinical trial at the 2024 European Society of Cardiology (ESC) Congress. The study was sponsored by the Bristol-Myers Squibb-Pfizer Alliance and iRhythm provided the Zio XT patch ECG monitor for long-term continuous monitoring (LTCM) that was used in the interventional (screening) arm of the study.

GUARD-AF was a prospective, parallel-group, randomized controlled trial designed to test whether screening for AF in people aged ≥70 years using an on-label Zio XT 14-day single-lead LTCM could identify patients with undiagnosed AF and reduce stroke. Participants were randomized 1:1 to screening with Zio XT LTCM or usual care. The primary efficacy and safety outcomes were hospitalization for all-cause stroke and bleeding, respectively.

During a median follow-up of 15 months among 11,905 enrolled patients from 149 US primary care sites (5,952 assigned to screening), the study found that Zio XT LTCM led to an increase in new diagnoses of AF versus usual care (5.0 versus 3.3%) through the end of follow-up. There was no significant difference between groups in incidence of the primary endpoint of hospitalization for stroke, although event rates were low and the trial was stopped before reaching enrollment of the planned total of 52,000 patients during the COVID-19 pandemic.²which reduces statistical power. The findings were presented by Dr. Renato Lopes, professor of medicine at the Duke Clinical Research Institute and Duke University, at the ESC Congress on September 1 and published simultaneously in two tandem manuscripts in the Journal of the American College of Cardiology (JACC)³ and the JACC: Clinical Electrophysiology.⁴