FDA Denies CytoSorbents' De Novo Request for DrugSorb-ATR Blood Purification Device
Key Insights
The FDA has issued a denial letter for CytoSorbents' DrugSorb-ATR (search) device, designed to reduce bleeding in CABG surgery patients who recently took ticagrelor, citing unresolved deficiencies.
CytoSorbents has met with the FDA and will continue discussions to address the issues, with plans to file a formal appeal within 60 days if resolution cannot be reached through dialogue.
Despite the setback, CEO Dr. Phillip Chan remains confident that the company can resolve the remaining issues and still anticipates a final regulatory decision in 2025 for the FDA-designated Breakthrough Device.
CytoSorbents Corporation (NASDAQ: CTSO) announced on May 1, 2025, that the U.S. Food and Drug Administration (FDA) has denied the company's De Novo Request for DrugSorb-ATR (search), its blood purification device designed to reduce bleeding severity in patients undergoing coronary artery bypass grafting (search) (CABG) surgery shortly after taking the blood thinner Brilinta (ticagrelor).
The FDA issued the denial letter on April 25, 2025, identifying specific deficiencies that must be addressed before the device can receive marketing authorization in the United States. CytoSorbents has already initiated discussions with the regulatory agency and plans to continue interactive conversations to resolve the outstanding issues. If these discussions prove unsuccessful, the company intends to file a formal appeal within 60 days.
"We remain deeply committed to bringing DrugSorb-ATR (search) to market as an important solution to address the serious, unmet medical need of preventing life-threatening bleeding in CABG patients treated with Brilinta," said Dr. Phillip Chan, Chief Executive Officer of CytoSorbents. "With no therapies currently available in the U.S., tens of thousands of patients remain at risk every year."
Despite this regulatory setback, the company maintains that it can address the FDA's concerns and still anticipates a final regulatory decision in 2025.
The Clinical Need for DrugSorb-ATR
Ticagrelor, marketed as Brilinta by AstraZeneca, is a potent antiplatelet medication commonly prescribed to patients with acute coronary syndrome (search) or a history of heart attack. While effective at preventing blood clots, the drug presents significant challenges when patients require urgent cardiac surgery.
Current guidelines recommend discontinuing ticagrelor at least five days before elective CABG surgery to reduce bleeding risks. However, many patients require urgent surgery and cannot wait the recommended period, placing them at substantially higher risk for severe perioperative bleeding complications.
DrugSorb-ATR (search) represents a potential solution to this clinical dilemma. The device uses highly porous polymer beads to remove ticagrelor from a patient's blood during cardiopulmonary bypass, potentially reducing bleeding complications without compromising the drug's prior therapeutic benefits.
Regulatory Journey and Breakthrough Status
The FDA previously granted DrugSorb-ATR (search) two Breakthrough Device Designations: one for ticagrelor removal and another for the removal of direct oral anticoagulants (DOACs) apixaban and rivaroxaban during urgent cardiothoracic procedures.
CytoSorbents submitted its De Novo Request in September 2024, which the FDA accepted for substantive review the following month. The company also received Medical Device Single Audit Program (MDSAP) certification in November 2024 and submitted a Medical Device License application to Health Canada.
Technology Platform and Global Presence
DrugSorb-ATR (search) utilizes the same polymer technology as CytoSorbents' flagship product, CytoSorb (search), which is already approved in the European Union and distributed in over 70 countries worldwide. CytoSorb has been used in more than 270,000 treatments globally for various applications, including cytokine removal in critical illnesses and the removal of certain blood thinners during cardiothoracic surgery in Europe.
The company's blood purification technology employs biocompatible, highly porous polymer beads that can actively remove toxic substances from blood through pore capture and surface adsorption. These cartridges integrate with standard hospital blood pumps, including dialysis machines, CRRT systems, ECMO circuits, and heart-lung machines.
Market Implications and Future Outlook
The denial represents a significant but potentially temporary setback for CytoSorbents, which has positioned DrugSorb-ATR (search) as a key growth driver for its U.S. market entry. The company's stock experienced volatility following the announcement, reflecting investor concerns about the timeline for potential commercialization.
Industry analysts note that while the FDA's decision delays market entry, the continued dialogue between CytoSorbents and the agency suggests that the identified deficiencies may be addressable without requiring substantial new clinical data.
If ultimately approved, DrugSorb-ATR (search) would address a significant unmet need in cardiac surgery. Approximately 10-15% of patients requiring CABG surgery have recently received ticagrelor, and these patients face a substantially higher risk of major bleeding events, increased blood product utilization, and prolonged ICU and hospital stays.
CytoSorbents continues to advance its broader portfolio of blood purification technologies while working to resolve the FDA's concerns regarding DrugSorb-ATR (search). The company maintains that it can address the outstanding issues and still achieve U.S. market authorization within its previously projected timeline.