Sipavibart antibody treatment for Long COVID

Effectiveness of Treating Post-COVID-19 Conditions (Long COVID) With the SARS-CoV-2 Specific Monoclonal Antibody, Sipavibart

PHASE2 · Nova Southeastern University · NCT07021794

This Phase II randomized, placebo-controlled trial will test whether the monoclonal antibody Sipavibart can reduce Long COVID symptoms in adults who had confirmed COVID-19 and still have symptoms after three months.

Quick facts

PhasePHASE2
Study typeInterventional
Enrollment100 (estimated)
Ages18 Years to 70 Years
SexAll
SponsorNova Southeastern University (other)
Drugs / interventionschemotherapy, radiation
Locations1 site (Fort Lauderdale, Florida)
Trial IDNCT07021794 on ClinicalTrials.gov

What this trial studies

This Phase II, randomized, placebo-controlled, double-blind trial compares Sipavibart (an anti–SARS‑CoV‑2 monoclonal antibody) versus placebo in two arms to examine safety and potential benefit for people with Long COVID. Eligible adults (18–70) must have documented SARS‑CoV‑2 infection on or before August 31, 2023 and persistent symptoms meeting ME/CFS and National Academy of Sciences criteria for more than three months, with PROMIS‑29 scores in the moderate-to-severe range. Participants will receive infusions and be followed for symptom scores, safety labs, and exploratory biomarkers of inflammation and viral activity. The study tests whether targeting the viral spike protein can lower symptom burden and biological signs linked to ongoing disease processes.

Who should consider this trial

Good fit: Adults aged 18–70 with a documented SARS‑CoV‑2 infection on or before August 31, 2023 who have had ongoing Long COVID symptoms for more than three months, meet ME/CFS and NAS criteria, and have a PROMIS‑29 score ≥60 are the intended participants.

Not a fit: People whose symptoms began after August 31, 2023, who do not meet ME/CFS or NAS criteria, who fall outside the 18–70 age range, or whose condition appears unrelated to persistent viral activity may be unlikely to benefit.

Why it matters

Potential benefit: If successful, Sipavibart could reduce symptom severity and inflammation for some people with Long COVID by targeting persistent viral activity.

How similar studies have performed: Monoclonal antibodies targeting the spike protein were effective for treating acute COVID-19 before Omicron, but evidence that they help Long COVID is preliminary and limited.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

An individual is eligible for inclusion if all of the following apply:

1. 18 to 70 years old,
2. Inciting event: Acute COVID documented by testing (PCR or antigen testing in a clinical setting).
3. Onset of COVID symptoms occurring on or prior to August 31st, 2023; and persistence of symptomatic expression of Long COVID (defined #6 below) for more than 3 months after COVID diagnosis.
4. Current symptomatic expression meets the case definition of ME/CFS.
5. PROMIS 29 score at screening of moderate to severe (≥60).
6. Meets National Academy of Sciences (NAS) criteria for Long COVID with the following provisions:

   1. Allowance for normal illnesses of aging, such as hypertension and diabetes, if the conditions are treated and are in demonstrable stable and acceptable ranges at the time of screening and assessment. Specifically, blood pressures \< 150 systolic and 90 diastolic mmHg are required.
   2. Allowance of stable comorbid conditions common in post viral illness, such as fibromyalgia, irritable bowel, interstitial cystitis, dysautonomia that have not required hospitalization in the two years prior to recruitment.
7. Able to provide written consent to study. Agrees to participate in follow-up visits.

Subject Exclusion Criteria

An individual is ineligible to participate if any of the following apply:

1. Known active acute SARS-CoV-2 infection ≤ 4 weeks from consent.
2. Known severe anemia, defined as \< 8 g/dL.
3. Known stroke that resulted in cognitive impairment within 3 months of enrollment.
4. Self-report of current treated or untreated major depression with psychotic or melancholic features, schizophrenia, bipolar disorder, delusional disorders, dementias of any type, or a history of CNS disorders that may affect cognitive function (i.e., epilepsy, stroke, brain tumor, multiple sclerosis, Parkinson's Disease, Alzheimer's disease), or substance abuse during the last two years, excluding cannabis products.
5. Allergy to any ingredient of the study drug (self-report)

   1. Sipavibart is supplied as 150 mg/mL of active ingredient in 20 mM L-histidine/L-histidine hydrochloride, 220 mM L-arginine hydrochloride, and 0.04% (w/v) polysorbate 80, at pH 6.0.
   2. Hypersensitivity to other humanized mAbs.
6. Current heavy alcohol or tobacco use (self-report). Alcohol consumption not to exceed approximately 15 drinks per week (with a drink defined as 12 oz beer, 5 oz wine, or 1.5 oz distilled spirits) and tobacco use not to exceed 20 cigarettes (or equivalent) per day during the last month.
7. Active chronic infections such as HIV, Hepatitis B Virus (HBV), and Hepatitis C Virus (HCV), indicated by self-report, and abnormal liver function tests (\>3x upper limit of normal) or evidence in the health record of chronic active hepatitis or human immunodeficiency virus (HIV).
8. Renal disease (self-report; laboratory results: renal insufficiency with serum creatinine \> 2.0 mg/dL or eGFR \< 44; or currently on renal dialysis)
9. Liver disease (self-report or laboratory results: hepatic insufficiency (bilirubin \>2.5mg/dL or transaminases \> 3X the upper limits of normal)
10. Uncontrolled diabetes, evidenced by combination of morning blood glucose and previous diagnosis of diabetes, AIC\>7
11. Diagnosed with congestive heart failure or significant arrythmia (ventricular tachycardia with a rapid rate at rest (\> 100 bpm), persistent atrial fibrillation, or second- or third-degree heart block)
12. Pre-existing sustained severe hypertension (BP \>180/110 mmHg in the sitting position)
13. Any of the following within 4 weeks of consent (Self-reported/medical record):

    1. an acute myocardial infarction or unstable angina
    2. uncontrolled arrhythmias causing symptoms or hemodynamic compromise
    3. acute myocarditis or pericarditis, uncontrolled acutely decompensated heart failure (acute pulmonary edema)
    4. acute pulmonary embolism
    5. suspected dissecting aneurysm
    6. severe hypoxemia at rest
    7. any acute or chronic disorder that may affect exercise performance, or
    8. if they are aggravated by exercise (e.g., infection, thyrotoxicosis, unable to cooperate)
14. Diagnosed bleeding disorders or use of blood-thinning medications.
15. Current or previous receipt of any COVID antiviral medication within 30 days prior to screening (self reported)
16. Currently have exclusionary diagnoses that could reasonably explain the symptoms of their fatiguing illness and their severity, using the exclusion criteria best described in the Ambiguities in case definition paper for CFS, as described in detail in \[13\] which clarifies exclusionary conditions. These exclusionary diagnoses that are not otherwise listed above comprise:

    1. Organ failure
    2. Chronic inflammatory diseases
    3. Major neurologic diseases that could cause fatigue or neurologic deficits
    4. Diseases requiring systemic treatment (i.e., transplantation, chemotherapy, radiation)
    5. Major endocrine diseases
    6. Untreated primary sleep disorders
    7. BMI \> 40 kg/m2
    8. Temporary conditions discovered at screening, such as

       * Temporary effects of medications
       * Temporary sleep deprivation
       * Untreated hypothyroidism, hypothyroidism that has been inadequately controlled during the last 3 months, or free T4 level not within normal limits
       * Active infection (for COVID-19 infection and other infections, participants may be rescreened six weeks after resolution of infection)
17. Known diagnosis of chronic Lyme disease with persistent symptoms, sequelae, or related therapy.
18. Any marijuana illicit drug use within 30 days of informed consent
19. Inability to discontinue symptomatic medications for the identified time periods
20. Moderate or severe immunocompromised patients, such as those described in the NIH COVID-Treatment Guidelines
21. Are scheduled for a surgery during the period of study participation, had minor surgery within three months prior to screening, or had major surgery within 6 months prior to screening
22. Participating in any interventional (including social-behavioral therapy) clinical trial of an investigational therapy within 6 weeks prior to consent, or planning to participate in another interventional clinical trial of an investigational therapy during the course of this study
23. COVID Vaccination within 90 days prior to entry and for the duration of the study
24. Pregnancy is excluded. Women of childbearing age will be given a pregnancy test.

Where this trial is running

Fort Lauderdale, Florida

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Post-COVID / Long-COVID, LongCOVID, Monoclonal antibody therapy, Post-viral conditions

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.