THUNDER Study Demonstrates Penumbra's THUNDERBOLT is Safe and Effective for Stroke Care

First and only CAVT device for stroke demonstrated high revascularization rates, short procedure times and low complication rates

ALAMEDA, Calif.,July 22, 2026/PRNewswire/ --Penumbra, Inc. (NYSE:PEN), the world's leading thrombectomy company, announced the results of THUNDER, an Investigational Device Exemption (IDE) study, to evaluate the safety and effectiveness of THUNDERBOLT™, the company's novel computer assisted vacuum thrombectomy (CAVT™) system, in stroke patients with emergent large vessel occlusion (ELVO). The data were presented this week during a late-breaking session at the Society of NeuroInterventional Surgery (SNIS) 23rd Annual Meeting.

"Mechanical thrombectomy is considered frontline treatment for stroke; however, current technologies may not fatigue and completely ingest the clot quickly or effectively at the site of the occlusion," said Donald Frei, M.D., co-principal investigator of THUNDER and neurointerventional radiologist at Swedish Medical Center, Denver, CO. "The THUNDER study demonstrated a high rate of complete clot ingestion with THUNDERBOLT, along with a low rate of complications—an important combination when striving for optimal patient outcomes."

"Mechanical thrombectomy is considered frontline treatment for stroke; however, current technologies may not fatigue and completely ingest the clot quickly or effectively at the site of the occlusion," said Donald Frei, M.D., co-principal investigator of THUNDER and neurointerventional radiologist at Swedish Medical Center, Denver, CO. "The THUNDER study demonstrated a high rate of complete clot ingestion with THUNDERBOLT, along with a low rate of complications—an important combination when striving for optimal patient outcomes."

THUNDER met its predefined performance goal, with 87.5% of cases achieving successful reperfusion, defined as mTICI 2b-3, after treatment with THUNDERBOLT. Notably, post-THUNDERBOLT, mTICI 2c-3 was achieved 70.4% of the time, which is associated with significantly better functional recovery and lower complication rates. Additionally:

• First-pass mTICI 2b-3 was 64.8%.

• Median time-to-revascularization was 20 min.

• Complete clot ingestion rate was 83%, demonstrating that the THUNDERBOLT system reliably facilitates the removal of clot.

• Device/procedure-related serious adverse events occurred in 2.8%, sICH in 0.9%, and the rate of all-cause mortality at 90 days was 11.7%, which is comparatively low to other thrombectomy therapies.

"In the THUNDER study, we observed that modulated aspiration facilitated consistent and complete clot removal when used in conjunction with standard-sized aspiration thrombectomy catheters," said David Fiorella, M.D., Ph.D., co-principal investigator of THUNDER and director of the Cerebrovascular Center at Stony Brook University Hospital, Stony Brook, NY. "Through this study, our early experience with THUNDERBOLT suggests that this technology could significantly advance treatment for stroke patients."

THUNDER is a single-arm, prospective, multicenter study with core-lab adjudication to evaluate the safety and effectiveness of THUNDERBOLT, which features Penumbra's CAVT technology, in stroke patients with ELVO. The study enrolled 216 patients across 29 U.S. centers.

"The THUNDER study provides robust clinical evidence supporting the safety and effectiveness of THUNDERBOLT for revascularization in ELVO stroke," said James F. Benenati, M.D., FSIR, chief medical officer at Penumbra. "These findings reinforce modulated aspiration as a significant advancement in mechanical thrombectomy and suggest it could expand physicians' treatment options to achieve rapid, effective revascularization in stroke, which is critical for patient outcomes."

Acute ischemic stroke (AIS) remains a major global health challenge, accounting for approximately 87% of all strokes and affecting an estimated 68 million people worldwidei. Approximately 20% to 42% of AIS cases are due to ELVOii.

THUNDERBOLT recently received U.S FDA clearance and CE Mark. It introduces modulated aspiration to Penumbra's neuro thrombectomy portfolio, offering advanced CAVT technology designed to detect, fatigue, and completely ingest clot at the site of the occlusion.

About PenumbraPenumbra, Inc., the world's leading thrombectomy company, is focused on developing the most innovative technologies for challenging medical conditions such as ischemic stroke, venous thromboembolism such as pulmonary embolism, and acute limb ischemia. Our broad portfolio, which includes computer assisted vacuum thrombectomy (CAVT), centers on removing blood clots from head-to-toe with speed, safety and simplicity. By pioneering these innovations, we support healthcare providers, hospitals and clinics in more than 100 countries, working to improve patient outcomes and quality of life. For more information, visitwww.penumbrainc.comand connect onInstagram,LinkedInandX.

Important Safety InformationAdditional information about Penumbra's products can be located on Penumbra's website athttps://www.penumbrainc.com/providers. Caution: Federal (USA) law restricts these devices to sale by or on the order of a physician. Prior to use, please refer to the Instructions for Use (IFU) for complete product indications, contraindications, warnings, precautions, potential adverse events, and detailed instructions for use. Please visitwww.peninc.info/riskfor the complete IFU Summary Statements.

Forward-Looking StatementsExcept for historical information, certain statements in this press release are forward-looking in nature and are subject to risks, uncertainties and assumptions about us. Our business and operations are subject to a variety of risks and uncertainties and, consequently, actual results may differ materially from those projected by any forward-looking statements. Factors that could cause actual results to differ from those projected include, but are not limited to: the risk that the pending acquisition by Boston Scientific Corporation will not be completed in the expected timeframe or at all, including the risk that required regulatory approvals will not be obtained; potential adverse effects to our business during the pendency of the acquisition, such as employee departures or diversion of management's attention from our business; failure to sustain or grow profitability or generate positive cash flows; failure to effectively introduce and market new products; delays in product introductions; significant competition; inability to further penetrate our current customer base, expand our user base and increase the frequency of use of our products by our customers; inability to achieve or maintain satisfactory pricing and margins; manufacturing difficulties; permanent write-downs or write-offs of our inventory or other assets; product defects or failures; unfavorable outcomes in clinical trials; inability to maintain our culture as we grow; fluctuations in foreign currency exchange rates; potential adverse regulatory actions; and the potential impact of any acquisitions, mergers, dispositions, joint ventures or investments we may make. These risks and uncertainties, as well as others, are discussed in greater detail in our filings with the Securities and Exchange Commission, including our Annual Report on Form 10-K for the year ended December 31, 2025, which we filed on February 25, 2026. There may be additional risks of which we are not presently aware or that we currently believe are immaterial which could have an adverse impact on our business. Any forward-looking statements are based on our current expectations, estimates and assumptions regarding future events and are applicable only as of the dates of such statements. We make no commitment to revise or update any forward-looking statements in order to reflect events or circumstances that may change.

Jennifer Heth

Parinaz Farzin

Penumbra, Inc.

Merryman Communications

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iTsao CW, Aday AW, Almarzooq ZI, et al. Heart Disease and Stroke Statistics-2023 Update: A Report From the American Heart Association. Circulation. Feb 21 2023;147(8):e93-e621. doi:10.1161/cir.0000000000001123iiRennert RC, Wali AR, Steinberg JA, et al. Epidemiology, Natural History, and Clinical Presentation of Large Vessel Ischemic Stroke. Neurosurgery. Jul 1 2019;85(suppl_1):S4-s8. doi:10.1093/neuros/nyz042

SOURCE Penumbra, Inc.