CytoSorbents has reported new real-world evidence showing an association between intraoperative CytoSorb use and substantially lower severe bleeding among patients undergoing urgent coronary artery bypass graft surgery after recent ticagrelor exposure. The patient-level matched analysis included 587 patients, comparing 198 CytoSorb-treated patients from the STAR-T Registry with 389 matched patients drawn from a previously published individual-patient-data meta-analysis who underwent surgery without the device. BARC-4 severe bleeding occurred in 21.8% of the CytoSorb group compared with 34.5% of controls, corresponding to a statistically significant 37% relative reduction with a p-value of 0.002.
The analysis also found significantly less 24-hour chest-tube drainage and fewer red-blood-cell transfusions among CytoSorb-treated patients, with no serious device-related adverse events reported. Investigators calculated that eight patients would need to be treated to prevent one severe bleeding event under the matched analysis. The findings are not from a randomized comparison, but they arrive at an important regulatory moment because CytoSorbents plans to incorporate the data into a new U.S. De Novo submission for DrugSorb-ATR after the FDA rejected an earlier application and asked for additional evidence supporting probable clinical benefit.
Why is urgent heart surgery particularly dangerous for patients who recently took ticagrelor?
Ticagrelor is a potent antiplatelet medicine commonly used after acute coronary syndromes and coronary interventions because it reduces the ability of platelets to form dangerous arterial clots. That same effect becomes a problem when a patient unexpectedly needs open-heart surgery. Surgeons rely on effective clot formation to control bleeding, and performing CABG while substantial active ticagrelor remains in circulation can increase transfusion requirements, chest-tube drainage and severe perioperative bleeding.
One traditional solution is simply to wait several days after the last ticagrelor dose before operating. CytoSorbents notes that surgery has historically been delayed roughly three to seven days to allow natural drug elimination, but some patients cannot safely wait because of unstable coronary disease or other urgent indications. A device capable of removing active drug during cardiopulmonary bypass could theoretically allow surgery to proceed while reducing the bleeding penalty associated with recent antiplatelet exposure.
How does CytoSorb remove ticagrelor from blood during bypass surgery?
CytoSorb is a hemoadsorption cartridge containing highly porous polymer beads. During extracorporeal circulation, blood passes through the cartridge, allowing selected hydrophobic substances within a particular molecular-size range to bind within the bead structure before blood returns to the patient. In urgent cardiac surgery, the cartridge can be incorporated into the cardiopulmonary bypass circuit that is already circulating the patient’s blood outside the body.
DrugSorb-ATR is the U.S. regulatory version of the technology being developed specifically around antithrombotic removal. Ticagrelor is highly protein bound, but the device is intended to continuously remove accessible active drug as equilibrium shifts between bound and unbound fractions. Pharmacokinetic work from the STAR-T program has been examining this removal mechanism alongside clinical bleeding outcomes.
How strong is the new 587-patient real-world bleeding result?
The absolute severe-bleeding difference was 12.7 percentage points: 21.8% with CytoSorb compared with 34.5% in the matched untreated group. That translates into the reported 37% relative reduction and a number needed to treat of eight to prevent one severe bleeding event. Significant improvements were also reported for chest-tube drainage and red-cell transfusion requirements, suggesting the signal was not limited to one categorical bleeding definition.
However, the analysis remains observational. Patients in the STAR-T Registry were not randomized contemporaneously against the 389 controls; instead, researchers used statistical matching against patient-level data from another source. Matching can reduce differences in measured baseline characteristics, but it cannot guarantee that all important confounders have been eliminated. Hospitals choosing CytoSorb may differ in surgical practice, transfusion thresholds or patient management in ways that affect outcomes independently of the device.
How do these findings compare with the randomized STAR-T trial?
The randomized, double-blind, sham-controlled STAR-T trial provides a more rigorous but complicated evidentiary foundation. It enrolled patients undergoing cardiothoracic surgery on cardiopulmonary bypass within two days of ticagrelor discontinuation and compared DrugSorb-ATR with a sham cartridge. The trial’s primary composite endpoint was not met, which ultimately contributed to the FDA denying the first De Novo application.
Despite that primary-endpoint failure, secondary analyses showed a 58% reduction in major bleeding under a more severe bleeding definition, with rates of 13.7% in the treatment group versus 30.0% in control and an estimated number needed to treat of six. The FDA later indicated that it did not have major concerns about device safety but wanted additional evidence supporting the proposed benefit claim. The new real-world analysis is strategically important because its direction is consistent with that favorable major-bleeding result while substantially expanding the number of device-treated patients in the regulatory evidence package.
Why was DrugSorb-ATR previously denied by the FDA despite some positive results?
De Novo authorization requires the FDA to conclude that the probable benefits of a novel device outweigh its probable risks for the proposed use. CytoSorbents’ initial submission faced a fundamental problem because STAR-T missed its prespecified primary endpoint, even though other bleeding analyses favored treatment. The company appealed, but the FDA upheld the denial while indicating that additional clinical and mechanistic evidence could potentially support a future application.
Rather than continuing the appeal, CytoSorbents decided to build a new submission. The company now plans to combine STAR-T randomized data with expanded real-world evidence, mechanistic information, usability testing, benchtop work and the existing safety package. CytoSorbents says the new real-world data could increase the number of treated patients represented in the next submission approximately fivefold to around 250.
When does CytoSorbents expect to return DrugSorb-ATR to the FDA?
The company is targeting a new De Novo submission for the ticagrelor indication in early 2027. Recent FDA pre-submission discussions focused on the type of mechanistic evidence needed and the suitability of the proposed evaluation model. DrugSorb-ATR retains FDA Breakthrough Device designation, which can support closer interaction with the agency but does not guarantee authorization.
CytoSorbents is also pursuing a separate regulatory pathway involving direct oral anticoagulants such as apixaban and rivaroxaban in urgent cardiac surgery. The company has held another pre-submission meeting with the FDA on that use and plans further discussion before determining the precise evidence package. This creates the possibility of two distinct U.S. De Novo applications addressing different classes of antithrombotic medicines.
Is CytoSorb already approved for antithrombotic removal outside the United States?
Yes. CytoSorbents states that CytoSorb is approved in the European Union for removal of ticagrelor and rivaroxaban during cardiopulmonary bypass and is distributed across a broad international footprint. The U.S. position is different: CytoSorb and DrugSorb-ATR are investigational for this use and have not been FDA approved or cleared.
That regulatory distinction is essential because European real-world use is helping generate evidence for the American application, but clinical adoption abroad does not substitute for FDA authorization. U.S. surgeons cannot assume the same labeled indication until the agency reviews the new package and reaches a favorable benefit-risk conclusion.
Why could blood-thinner removal matter beyond ticagrelor?
Modern cardiovascular patients frequently receive increasingly potent antithrombotic medicines, while aging populations mean more treated patients will eventually present for urgent operations. Direct oral anticoagulants including apixaban and rivaroxaban create similar timing dilemmas when surgery cannot be postponed long enough for normal drug clearance. Some agents have pharmacological reversal strategies, but availability, cost and indication can vary.
An extracorporeal removal approach is attractive because the same broad technological concept could potentially address several drugs while the patient is already on bypass. Yet every drug has different binding, distribution and pharmacokinetic behavior, meaning efficacy cannot simply be extrapolated from ticagrelor. CytoSorbents will need indication-specific evidence and regulatory review for each major antithrombotic category.
What should cardiac surgeons and investors watch before the next De Novo submission?
The biggest question is whether CytoSorbents can assemble enough converging evidence to overcome the failed original primary endpoint. The new 587-patient matched analysis gives the company a much larger real-world dataset and produces a severe-bleeding reduction consistent with favorable signals from STAR-T, but observational evidence still sits below a successful randomized pivotal endpoint in the traditional evidence hierarchy.
The FDA has already indicated that safety is not the principal unresolved problem, which narrows the regulatory debate toward probable benefit and the proposed label. If the additional mechanistic and real-world evidence persuades the agency, DrugSorb-ATR could become an unusual cardiac-surgery technology whose value comes from physically removing a pharmaceutical from the bloodstream when clinicians no longer have the luxury of waiting for that drug to disappear naturally.
