Full 12-Month Data from the ACCCESS U.S. Pivotal Study in Complete Concentric Collapse Patients Presented at ISSS 2026

Full 12-Month Data from the ACCCESS U.S. Pivotal Study in Complete Concentric Collapse Patients Presented at ISSS 2026

Genio® bilateral stimulation delivered a 74.3% median reduction in AHI at 12 months, with no device- or procedure-related serious adverse events

PMA supplement submitted to the FDA to expand Genio’s indication to CCC patients

Mont-Saint-Guibert, Belgium – October 15, 2026, 10:05 pm CET / 4:05 pm ET – Nyxoah SA (Euronext Brussels/Nasdaq: NYXH) (“Nyxoah” or the “Company”), a medical technology company that develops breakthrough treatment alternatives for Obstructive Sleep Apnea (OSA) through neuromodulation, today announced that the complete 12-month results of the ACCCESS U.S. pivotal study were presented at the International Surgical Sleep Society (ISSS) annual meeting, taking place October 15-16, 2026, in Los Angeles, California. The data were presented by Colin Huntley, MD, Co-principal Investigator of the ACCCESS study. They confirm the top-line results announced on September 2, 2026, and show strong efficacy and safety outcomes with Genio® bilateral stimulation in patients with Complete Concentric Collapse (CCC) of the soft palate, a population with no commercially available neurostimulation option in the United States today.

Key Highlights

• Efficacy
  • Both co-primary efficacy endpoints were met: Apnea-Hypopnea Index (AHI) responder rate, per the Sher criteria¹, of 77.2% and Oxygen Desaturation Index (ODI) responder rate of 87.7%, both on a Full Analysis Set basis (p<0.001).
  • In the per protocol population, mean AHI decreased from 33.6 to 10.4 events per hour, a median reduction of 74.3% from baseline. Mean ODI decreased from 32.6 to 10.9 events per hour, a median reduction of 71.9% (both p<0.001).
• Safety
  • No device- or procedure-related serious adverse events (SAEs) were reported through 12 months. Four SAEs were reported, all unrelated to the device or the procedure (overall SAE rate of 7.5%).
• Quality of life and patient-reported outcomes
  • Mean Epworth Sleepiness Scale (ESS) score improved by 5.3 points and mean Functional Outcomes of Sleep Questionnaire (FOSQ-10) score improved by 2.3 points (both p<0.001).
  • 94.7% of patients reported an improvement, and 97.4% were satisfied and would choose the implant again.

Patients evaluable in the ACCCESS study² had a mean baseline AHI of 33.1 events per hour, and close to two thirds (63.8%) presented with severe OSA. CCC was confirmed by an independent Drug-Induced Sleep Endoscopy (DISE) core laboratory, sleep tests were scored by an independent core laboratory, and adverse events were adjudicated by an independent Clinical Events Committee.

Today, Nyxoah has submitted a premarket approval (PMA) supplement to the U.S. Food and Drug Administration (FDA) to expand Genio’s indication to CCC patients. Patients in the ACCCESS study will continue to be followed for three years post-implant.

“In our daily practice, we regularly identify CCC patients for whom we currently have no commercially available hypoglossal nerve stimulation option to offer in the United States. The 12-month ACCCESS data show that Genio can address this need. Statistically significant reductions were reported in AHI and ODI, with no device- or procedure-related serious adverse events, and patients reported reduced daytime sleepiness and improved quality of life. This could give U.S. physicians an additional therapeutic approach for OSA patients with CCC,” commented Edward Mezerhane, MD, FAASM, FACP, DABOM, CPI, sleep medicine physician at PharmaDev Clinical Research Institute (Miami, Florida), and Co-principal Investigator of the ACCCESS study.

“We are pleased that ACCCESS delivered a 74.3% median reduction in AHI at 12 months, with no device- or procedure-related serious adverse events, in OSA patients with CCC. These patients have no commercially available neurostimulation option in the U.S. today, and this remains an important unmet clinical need. We have submitted our PMA supplement to the FDA, and we remain confident in our ability to bring Genio to more OSA patients and to deliver on our mission to make sleep simple,” commented Liam Kelly, Nyxoah’s Chief Executive Officer.

About the ACCCESS study

ACCCESS is a multicenter, prospective, open-label pivotal study conducted in the United States, designed to assess the safety and efficacy of the Genio system in adult patients with moderate to severe OSA and CCC of the soft palate who have failed, do not tolerate, or refused positive airway pressure treatment. The study’s co-primary efficacy endpoints are the AHI responder rate, per the Sher criteria, and the ODI responder rate, both assessed at 12 months post-implant, with patients followed for three years post-implant. CCC patients are currently contraindicated for unilateral hypoglossal nerve stimulation in the United States. Genio has been approved for CCC patients in Europe since 2021, while in the United States, no commercially available neurostimulation treatment option exists for this population today.

About Nyxoah

Nyxoah is a medical technology company focused on the development and commercialization of innovative solutions to treat OSA. Nyxoah’s lead solution is the Genio system, a patient-centered, leadless and battery-free hypoglossal neurostimulation therapy for OSA, the world’s most common sleep disordered breathing condition that is associated with increased mortality risk and cardiovascular comorbidities. Nyxoah is driven by the vision that OSA patients should enjoy restful nights and feel enabled to live their life to its fullest.

Following the successful completion of the BLAST OSA study, the Genio system received its European CE Mark in 2019. Nyxoah completed two successful IPOs: on Euronext Brussels in September 2020 and NASDAQ in July 2021. Following the positive outcomes of the BETTER SLEEP study, Nyxoah received CE mark approval for the expansion of its therapeutic indications to Complete Concentric Collapse (CCC) patients, currently contraindicated in competitors’ therapy. Additionally, the Company announced positive outcomes from the DREAM IDE pivotal study in 2024 and received approval from the FDA in August 2025, with the treatment of CCC patients included in the warning section of our indications for use.

For more information, please visit http://www.nyxoah.com.

Caution – CE marked since 2019. FDA approved in August 2025 as prescription-only device.

Forward-looking statements

Certain statements, beliefs and opinions in this press release are forward-looking, which reflect the Company’s or, as appropriate, the Company directors’ or management’s current expectations regarding the Genio system; the ACCCESS study and the results thereof; the potential advantages of the Genio system; Nyxoah’s goals with respect to the potential use of the Genio system; the PMA supplement to the FDA and the timing and outcome of any FDA review; the Company's commercialization strategy and growth in the U.S. market; the Company's results of operations, financial condition, liquidity, performance, prospects, growth, future revenue and strategies. By their nature, forward-looking statements involve a number of risks, uncertainties, assumptions and other factors that could cause actual results or events to differ materially from those expressed or implied by the forward-looking statements. These risks, uncertainties, assumptions and factors could adversely affect the outcome and financial effects of the plans and events described herein. These risks and uncertainties include, but are not limited to, the risks and uncertainties set forth in the “Risk Factors” section of the Company’s Annual Report on Form 20-F for the year ended December 31, 2025, filed with the Securities and Exchange Commission (“SEC”) on March 26, 2026 and subsequent reports that the Company files with the SEC. A multitude of factors including, but not limited to, changes in demand, competition and technology, can cause actual events, performance or results to differ significantly from any anticipated development. Forward-looking statements contained in this press release regarding past trends or activities are not guarantees of future performance and should not be taken as a representation that such trends or activities will continue in the future. In addition, even if actual results or developments are consistent with the forward-looking statements contained in this press release, those results or developments may not be indicative of results or developments in future periods. No representations and warranties are made as to the accuracy or fairness of such forward-looking statements. As a result, the Company expressly disclaims any obligation or undertaking to release any updates or revisions to any forward-looking statements in this press release as a result of any change in expectations or any change in events, conditions, assumptions or circumstances on which these forward-looking statements are based, except if specifically required to do so by law or regulation. Neither the Company nor its advisers or representatives nor any of its subsidiary undertakings or any such person's officers or employees guarantees that the assumptions underlying such forward-looking statements are free from errors nor does either accept any responsibility for the future accuracy of the forward-looking statements contained in this press release or the actual occurrence of the forecasted developments. You should not place undue reliance on forward-looking statements, which speak only as of the date of this press release.

Contacts:

Nyxoah

Loïc Moreau, Interim CFO

IR@nyxoah.com

Rémi Renard, Head of Investor Relations & Corporate Communication

IR@nyxoah.com

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¹ An AHI responder, per the Sher criteria, is defined as a subject with an AHI reduction of at least 50% from baseline and an AHI score of less than 20 events per hour on the 12-month polysomnography (PSG). An ODI responder is defined as a subject which demonstrates an ODI reduction of at least 25% from baseline on the 12-month PSG.
² An evaluable patient is defined as a patient that was implanted, activated and had at least one in-lab polysomnography post-activation.

Attachment

• ENGLISH_ACCCESS Data Presentation at ISSS_PR_FINAL