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Ibuzatrelvir alone or with remdesivir for severely immunocompromised adults with COVID-19

AN INTERVENTIONAL EFFICACY AND SAFETY, PHASE 3, RANDOMIZED, DOUBLE-BLIND, 3-ARM STUDY TO INVESTIGATE IBUZATRELVIR IN ADULTS WITH SYMPTOMATIC COVID-19 WHO ARE SEVERELY IMMUNOCOMPROMISED

Phase 3 Interventional Pfizer · NCT07013474

This will test whether ibuzatrelvir, taken alone or together with remdesivir, helps severely immunocompromised adults who recently developed COVID-19 symptoms.

Quick facts

PhasePhase 3
Study typeInterventional
Enrollment300 (estimated)
Ages18 Years and up
SexAll
SponsorPfizer Industry-sponsored
Drugs / interventionsrituximab, CAR-T
Locations54 sites (Sacramento, California and 53 other locations)
Trial IDNCT07013474 on ClinicalTrials.gov

What this trial studies

This is a randomized, double-blinded, double-dummy, phase 3 trial that compares three arms: remdesivir IV alone, oral ibuzatrelvir alone, and the combination of ibuzatrelvir with remdesivir. Eligible adults are severely immunocompromised, have a confirmed SARS‑CoV‑2 infection, and developed symptoms within five days; participants may be non‑hospitalized or hospitalized only for observation or to receive the intervention and must not require supplemental oxygen. Ibuzatrelvir is taken orally twice daily while remdesivir is administered as a daily IV infusion, with matching placebos used to maintain blinding. The study tests both efficacy and safety outcomes to see if the oral drug, alone or with remdesivir, reduces progression or persistence of symptomatic COVID‑19 in this high‑risk group.

Who should consider this trial

Good fit: Adults (≥18) who are severely immunocompromised—for example due to organ transplant, active hematologic malignancy, recent CAR‑T/HCT, or B‑cell depleting therapy—with confirmed SARS‑CoV‑2 infection and symptom onset within the past five days, who are non‑hospitalized or hospitalized without need for supplemental oxygen.

Not a fit: People who require supplemental oxygen for COVID‑19, are not severely immunocompromised, are more than five days from symptom onset, or are under 18 are unlikely to qualify or receive benefit from this protocol.

Why it matters

Potential benefit: If successful, the treatment options could shorten illness, prevent progression to severe COVID‑19, and reduce persistent infection in severely immunocompromised patients.

How similar studies have performed: Remdesivir has shown antiviral benefit in prior COVID‑19 studies, but ibuzatrelvir and the specific oral plus IV combination remain novel in this population and have not yet been proven effective.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

1. 18 years of age or older at screening who are non-hospitalized or hospitalized for observation or with the intent of administering the study intervention.
2. Confirmed SARS-CoV-2 infection as determined by RAT (or other locally approved test) collected within 2 days prior to randomization. Initial onset of symptoms attributable to COVID-19 within 5 days prior to the day of randomization and at least 1 of the specified symptoms attributable to COVID-19 present on the day of randomization.
3. Severely immunocompromised due to:

   * Solid organ or islet cell transplant recipient who is receiving immunosuppressive therapy;
   * Active hematologic malignancy (eg, chronic lymphocytic leukemia, non-Hodgkin lymphoma, multiple myeloma, acute leukemia);
   * Receipt of CAR-T-cell therapy or HCT either within 2 years of transplantation or who are receiving immunosuppressive therapy;
   * Currently receiving or recently received B-cell depleting therapies (eg, rituximab), where the immunosuppressive effect is still ongoing.

Exclusion Criteria:

1. Severe COVID-19, or current need for supplemental oxygen for treatment of COVID-19.
2. Receiving dialysis or have current kidney failure (ie, eGFR consistently \<15 mL/min/1.73 m2)
3. Active liver disease
4. History of hypersensitivity or other contraindication to any of the components of the study interventions, as determined by the investigator
5. Suspected or confirmed concurrent active systemic infection other than COVID-19 that may interfere with the evaluation of response to the study intervention.
6. Life expectancy less than 30 days at study entry due to an underlying condition, in the judgement of the investigator.
7. Any medical or psychiatric condition including recent (within the past year) or active suicidal ideation/behavior or laboratory abnormality that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate for the study.
8. Has received any other antiviral for the treatment of the current COVID-19 infection
9. Current use of any prohibited concomitant medication(s) or unwillingness or inability to use a required concomitant medication(s).
10. Current or previous administration of an investigational product (drug or vaccine) within 30 days (or as determined by local requirement) or 5 half lives preceding the first dose of study intervention used in this study (whichever is longer). Authorized or products with conditional approval are not considered investigational.
11. Prior participation in this trial or any clinical trial of ibuzatrelvir.
12. Females who are pregnant, breastfeeding, or who are planning to become pregnant within the timeframe of the study.
13. Investigator site staff directly involved in the conduct of the study and their family members, site staff otherwise supervised by the investigator, and sponsor and sponsor delegate employees directly involved in the conduct of the study and their family members.

Where this trial is running

Sacramento, California and 53 other locations

+4 more sites — see ClinicalTrials.gov for the full list.

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 → Find more trials like this →
Conditions COVID-19 InfectionCOVID-19 infectionpneumoniarespiratory tract infectionscoronavirus infectionRNA virus infectionlung diseasepneumonia, viral
Last reviewed 2026-06-13 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.