ExThera was not the sponsor. No patients were enrolled.

This study will use a prospective, open, single-arm design, in which a group of 100 patients with a diagnosis of prolonged COVID, previously selected according to inclusion and exclusion criteria, and who have undergone informed consent process and have signed the informed consent form, undergo two hemoperfusion procedures with the Seraph 100 filter, on consecutive days. They are then evaluated at day 3 and 4 weeks, to complete the safety and effectiveness assessment.

This will be a prospective, open-label, single-arm, pilot study, in which a group of 100 PC patients will undergo two hemoperfusion procedures, to verify the safety and preliminary efficacy of the Seraph 100 device. Eligible patients will be invited to participate and once they sign the Informed Consent (IC) they will undergo two hemoperfusion procedures, on consecutive days, of -4 hours duration each time, using a multicomponent apheresis machine with the Seraph 100 filter. Patients will be followed for a total of 30 days, to monitor the presence of AEs (safety) and possible changes in clinical outcomes (preliminary efficacy).

Inclusion Criteria:

Subjects will be considered eligible for participation in the study if they meet all the following inclusion criteria:

1. Adult patients age of 18-85 (had 18th birthday but did not have 85th birthday).
2. History of COVID 19 infection established by positive polymerase chain reaction (PCR) test or by compatible clinical testing (e.g. rapid antigen, serum testing, or other relevant clinical documentation).
3. Persistent symptoms for 12 or more weeks after acute COVID 19 infection including fatigue and one or more of the following: myalgia or generalized aches and pains; joint pain; dizziness or unsteadiness; cognitive dysfunction (mental fog).
4. Patient (legally designated representative) has completed the Informed Consent process prior to enrollment into this study.
5. Patient (legally designated representative) is willing to comply with the study protocol -

Exclusion Criteria:

Subjects meeting any of the following criteria will not be recruited for the study:

1. History of heparin allergy.
2. History of heparin-induced thrombocytopenia.
3. Pregnancy or breastfeeding.
4. Life expectancy is less than 30 days.
5. The patient is currently enrolled in another drug or device trial. Patients who cannot tolerate placement of double-lumen catheter.
6. Unable to obtain informed consent from either patient or legally authorized representative (LAR)Any subject who, in the investigator's judgment, is considered unsuitable for participation in this trial.

After verification of eligibility and signature of consent:

1. The patient must be able to perform a hemoperfusion procedure with an apheresis machine.

Following completion of the study, results of this research will be in a scientific journal. Data will be available immediately following publication, with no end date, with data sharing at the discretion of the Sponsor.

Unblinded