iRhythm Technologies Announces Results of GUARD-AF Trial

Rhea-AI Summary

iRhythm Technologies (NASDAQ:IRTC) presented results from the GUARD-AF trial at the European Society of Cardiology Congress 2024. The trial, using iRhythm's Zio® XT patch for long-term continuous monitoring (LTCM), aimed to evaluate screening for undiagnosed atrial fibrillation (AF) in elderly individuals.

Key findings include:

• Screening with Zio® XT LTCM led to increased AF diagnosis (5.0% vs 3.3%) over 15 months
• No significant difference in stroke hospitalization rates
• Increased oral anticoagulation initiation in the screened group (4.2% vs 2.8%)
• 88% of detected AF cases were low-burden paroxysmal AF

The study demonstrates the feasibility of primary care-initiated, home-based monitoring for AF detection in older populations.

Positive

• Increased AF diagnosis rate (5.0% vs 3.3%) using Zio® XT LTCM
• Higher initiation of oral anticoagulation in the screened group (4.2% vs 2.8%)
• No increase in hospitalization for bleeding in the screened group
• Successful implementation of virtual, home-based diagnostics with high wear time and analyzable data
• Demonstrated feasibility of large-scale pragmatic trials using Zio LTCM service

Negative

• No significant difference in stroke hospitalization rates between screened and usual care groups
• Study stopped before achieving planned enrollment of 52,000 patients, reducing statistical power

Medical Research Analyst

The GUARD-AF trial results offer significant insights into AF screening using iRhythm's Zio® XT patch. The study found a higher rate of AF diagnosis in the screening group (5.0% vs 3.3%), demonstrating the effectiveness of LTCM in detecting undiagnosed AF. However, the primary endpoint of reduced stroke hospitalization was not met, likely due to reduced statistical power from truncated enrollment.

Key takeaways include:

• Feasibility of primary care-initiated, home-based monitoring
• High prevalence of low-burden paroxysmal AF (88% of detected cases)
• Increased initiation of oral anticoagulation in the screening group

These findings suggest that LTCM could be valuable for early AF detection, potentially leading to earlier interventions and better management of cardiovascular risk factors.

Cardiologist

The GUARD-AF trial results are intriguing but leave some questions unanswered. While the increased AF detection rate is promising, the lack of significant difference in stroke hospitalization is noteworthy. This could be due to the study's limitations or suggest that early AF detection alone may not be sufficient to reduce stroke risk in the short term.

The high prevalence of low-burden paroxysmal AF (88% of detected cases) highlights the importance of LTCM over shorter monitoring periods. However, the clinical significance of these brief AF episodes remains debatable. Future studies should focus on longer follow-up periods and assess a broader range of outcomes, including heart failure and cardiovascular hospitalizations, to fully understand the impact of early AF detection on patient outcomes.

Financial Analyst

For iRhythm Technologies (NASDAQ:IRTC), the GUARD-AF trial results present a mixed picture. On the positive side, the study demonstrates the effectiveness of Zio® XT in detecting undiagnosed AF, which could drive increased adoption in primary care settings. The feasibility of home-based monitoring and virtual enrollment also aligns well with current healthcare trends.

However, the lack of a significant reduction in stroke hospitalization may temper enthusiasm for widespread screening programs. Investors should closely monitor future studies, particularly those assessing a wider range of outcomes and longer follow-up periods. The company's involvement in ongoing trials like AMALFI and its focus on undiagnosed arrhythmia pilot programs suggest a strong pipeline for future growth. Overall, while the results are not overwhelmingly positive, they do support the potential for expanded use of iRhythm's technology in AF screening and management.

• GUARD-AF trial results presented at European Society of Cardiology (ESC) Congress 2024
• Leveraging 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 iRhythm’s Zio^® XT¹ LTCM led to increase in new diagnosis of AF (5.0% vs 3.3%) over an average follow-up of 15 months.
• No difference in stroke hospitalization vs usual care in the context of reduced statistical power due to truncated enrollment and follow-up.

SAN FRANCISCO, Sept. 01, 2024 (GLOBE NEWSWIRE) -- iRhythm Technologies, Inc. (NASDAQ:IRTC), a leading digital health care 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 UndiAgnosed atRial fibrillation in elderly inDividuals) randomized clinical trial at the European Society of Cardiology (ESC) Congress 2024. The trial was sponsored by Bristol-Myers Squibb-Pfizer Alliance and iRhythm provided the Zio XT patch ECG long-term continuous monitoring (LTCM) monitor 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 due to all-cause stroke and bleeding, respectively.

During a median follow-up of 15 months in 11,905 enrolled patients from 149 primary care sites in the US (5,952 assigned to screening), the study found that Zio XT LTCM led to an increase in new diagnosis of AF vs usual care (5.0 vs 3.3%) through the end of follow-up. There was no significant difference between groups in incidence of the primary endpoint of stroke hospitalization, although event rates were low and the trial was stopped before achieving enrollment of the planned total of 52,000 patients during the COVID-19 pandemic², thereby reducing statistical power. 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 simultaneously published in two tandem manuscripts in the Journal of the America College of Cardiology (JACC)³ and the JACC: Clinical Electrophysiology.⁴

“Owing in part to the low event rate and truncated enrollment, the study found no reduction in the rate of stroke,” said Dr. Lopes. “However, there are some important lessons here. Our study confirms that AFib is common in older patients and can be identified with cardiac monitoring in primary care — upstream of cardiology care, which many patients will not have access to. Most participants with AFib also had short, infrequent episodes that would be missed with a pulse check, single ECG, shorter duration of monitoring. Identification of these short episodes could be a useful prompt for physicians to more aggressively treat heart disease risk factors and may reduce the downstream risk of heart failure, which will be evaluated in future trials.”

The study had several notable implications:

• Screening with Zio XT LTCM led to an increase in diagnosis of AF over the maximum 2.5 years of follow up vs usual care (5.0% vs 3.3%), an increase in initiation of oral anticoagulation that is used for prevention of stroke in AF (4.2% vs 2.8%), and no increase in the rate of hospitalization for bleeding.³
• Primary care-initiated home-based monitoring in an older population is feasible. GUARD-AF is the largest randomized trial to evaluate the impact of AF screening with a patch-based ECG monitor on care delivery in a primary care setting; more than half of participants enrolled were women.³
• Virtual, home-based diagnostics are feasible. In GUARD-AF, 20% of participants were enrolled virtually and received the Zio XT LTCM device by mail for self-application. Wear time and analyzable time were similar and high in self-applied and clinic-applied groups³, confirming prior studies and clinical experience with Zio LTCM service.⁵
• In the 252 participants with AF detected on 14-day LTCM, most (88%) had low-burden paroxysmal AF. Of those with detected AF, most had AF < 1.0% of the time³, suggesting that many patients with diagnosed AF may miss detection with 12-lead ECG (10 seconds), smartwatch ECG (30 seconds), or ambulatory monitoring of shorter duration such as 48 hours. Only 32 of 252 had AF at the start of the ECG recording.

Additionally, this research underscores how large pragmatic trials powered by the Zio LTCM service are feasible at scale. iRhythm’s clinical research services have supported over 100 prospective studies at nearly 500 sites in over 40,000 participants.

“These findings support the totality of evidence that undiagnosed AFib is common and can be found with Zio’s 14-day long-term monitoring — even when it is not likely to be found with point-of-care ECGs or short-term monitors due to the short, infrequent episodes in the early stages of atrial fibrillation,” said Mintu Turakhia MD, iRhythm’s Chief Medical and Scientific Officer and EVP, Product Innovation. “iRhythm’s undiagnosed arrhythmia pilot programs leverage many features seen in GUARD-AF, such as virtual enrollment and self-applied patches at home. These programs, as well as ongoing clinical trials, such as AMALFI⁶, and those in development will have longer follow-up or assess a wider range of outcomes, including heart failure, which occurs in one-third of patients with AFib, along with cardiovascular hospitalization, health care utilization, and costs.”

Also at ESC, Evangelos Hytopoulos, PhD, iRhythm’s Sr. Director of Data Science, presented separate work performed in collaboration with Scripps Research, New insights from the ECG: screening and prediction⁷, that used machine learning on ECG signal of 14-days of patch-based monitoring without AF to successfully predict episodes of AF in the subsequent year. The research presented is part of a scientific study only and is not part of any commercial product offering in any market.

About iRhythm Technologies, Inc.
iRhythm is a leading digital health care company that creates trusted solutions that detect, predict, and prevent disease. Combining wearable biosensors and cloud-based data analytics with powerful proprietary algorithms, iRhythm distills data from millions of heartbeats into clinically actionable information. Through a relentless focus on patient care, iRhythm’s vision is to deliver better data, better insights, and better health for all. To learn more about iRhythm, go to iRhythmtech.com.

Forward-Looking Statements
This press release contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934 and the Private Securities Litigation Reform Act of 1995. These statements include statements regarding clinical developments and market opportunity. Such statements are based on current assumptions that involve risks and uncertainties that could cause actual outcomes and results to differ materially. These risks and uncertainties, many of which are beyond our control, include risks described in the section entitled “Risk Factors” and elsewhere in the company’s public filings with the Securities and Exchange Commission. These forward-looking statements speak only as of the date hereof and should not be unduly relied upon. iRhythm disclaims any obligation to update these forward-looking statements.

iRhythm Contact Information

Investor Relations Contact
Stephanie Zhadkevich
investors@irhythmtech.com

Media Contact
Kassandra Perry
irhythm@highwirepr.com

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¹ The Zio XT Patch is a prescription-only, single patient use, continuously recording ECG monitor that can be worn up to 14 days. It is indicated for use on patients who may be asymptomatic or who may suffer from transient symptoms such as palpitations, shortness of breath, dizziness, light-headedness, pre-syncope, syncope, fatigue, or anxiety.
² Singer DE, et al. American Heart Journal. 2022 Jul:249:76-85. doi: 10.1016/j.ahj.2022.04.005.
³ Lopes RD, et al. J Am Coll Cardiol. 2024.
⁴ Singer DE, et al. JACC Clin Electrophysiol. 2024.
⁵ Goergen JA, et al. Heart Rhythm. 2023 Mar;20(3):407-413. doi: 10.1016/j.hrthm.2022.11.020.
⁶ About AMALFI https://www.amalfitrial.org/about 
⁷ M Gadaleta, et al, Predicting 1-year atrial fibrillation risk from a patch-based ambulatory ECG monitoring without atrial fibrillation, European Society of Cardiology (ESC) 2024 Congress, August 30 – September 2, London.

FAQ

What were the main results of the GUARD-AF trial for iRhythm Technologies (IRTC)?

The GUARD-AF trial showed that screening with iRhythm's Zio® XT LTCM led to increased atrial fibrillation (AF) diagnosis (5.0% vs 3.3%) and higher initiation of oral anticoagulation (4.2% vs 2.8%) compared to usual care over a 15-month follow-up period. However, there was no significant difference in stroke hospitalization rates between the groups.

How did the GUARD-AF trial impact iRhythm Technologies' (IRTC) Zio® XT patch performance?

The GUARD-AF trial demonstrated the effectiveness of iRhythm's Zio® XT patch in detecting undiagnosed atrial fibrillation in a primary care setting. The study showed high wear time and analyzable data for both self-applied and clinic-applied Zio XT LTCM devices, confirming its feasibility for home-based diagnostics.

What was the significance of the GUARD-AF trial results for iRhythm Technologies (IRTC) presented at ESC Congress 2024?

The GUARD-AF trial results presented at ESC Congress 2024 highlighted iRhythm Technologies' Zio® XT patch effectiveness in detecting undiagnosed AF in elderly individuals. The study demonstrated the feasibility of primary care-initiated, home-based monitoring and supported the potential for large-scale pragmatic trials using iRhythm's Zio LTCM service.

How did the GUARD-AF trial affect iRhythm Technologies' (IRTC) approach to AF detection?

The GUARD-AF trial reinforced iRhythm Technologies' approach to AF detection by demonstrating that undiagnosed AF is common and can be effectively identified using 14-day long-term monitoring with Zio® XT. This supports iRhythm's undiagnosed arrhythmia pilot programs and ongoing clinical trials focusing on longer follow-up and wider outcome assessments.