A Study to Learn About a Study Medicine Called Ibuzatrelvir in People With Coronavirus Disease 2019 (COVID-19) and a Severely Compromised Immune System

Overview

Sponsor-declared trial summary

Key facts

Sponsor

Pfizer Inc.

Participant type

Patients

Age range

18-64 years, 65+ years

Gender

Male and Female

Therapeutic area

Diseases [C] - Virus Diseases [C02]

Trial duration

30 Sep 2025 → ongoing

Decision date (initial)

2025-08-13

Transition trial

No

Low-intervention

No

Rare-disease indication

No

Vulnerable population

No

Funding sources

Pfizer Inc

Trial design

CTIS Part I — objectives, methods, condition coding

Main objective

Scope: Pharmacokinetic, Safety, Efficacy

To compare the efficacy of ibuzatrelvir alone or combined with remdesivir on clinical and virological responses in symptomatic adult participants with COVID-19 who are severely immunocompromised.

Secondary objectives 4

1. To describe the effect of ibuzatrelvir alone or combined with remdesivir on the targeted COVID-19 symptom duration and severity and virological responses in symptomatic adult participants with COVID-19 who are severely immunocompromised.
2. To describe the effect of ibuzatrelvir alone or combined with remdesivir on healthcare utilization in symptomatic adult participants with COVID-19 who are severely immunocompromised.
3. To describe the effect of ibuzatrelvir alone or combined with remdesivir on virologic responses over time in symptomatic adult participants with COVID-19 who are severely immunocompromised.
4. To describe the safety and tolerability of ibuzatrelvir and remdesivir in symptomatic adult participants with COVID-19 who are severely immunocompromised.

Conditions and MedDRA coding

Coronavirus Disease 2019 (COVID-19)

Regulatory references

Scientific advice from competent authorities

Food And Drug Administration, European Medicines Agency

Plan to share IPD

Yes

IPD plan description

Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests.

Eligibility criteria

Principal inclusion / exclusion criteria as submitted by sponsor

Inclusion criteria 3

1. 18 years of age or older (or the minimum age of consent in accordance with local regulations) at screening who are non-hospitalized or hospitalized for observation or with the intent of administering the study intervention.  Refer to Appendix 4 for reproductive criteria for male (Section 10.4.1) and female (Section 10.4.2) participants.
2. Confirmed SARS-CoV-2 infection as determined by RAT (or other locally approved test as noted in Section 8.2.4) in nasal specimen 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 (see Section 10.10 for criteria). Randomization must occur no later than the fifth day, where the onset of symptoms is the first day.
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 13

1. Severe COVID-19, or current need for supplemental oxygen for treatment of COVID-19 (for definition of “severe COVID-19” refer to Section 6.9.4.).
2. Receiving dialysis or have current kidney failure (ie, eGFR consistenly <15 mL/min/1.73 m2) using the serum creatinine-based CKD-EPI formula.
3. Active liver disease with AST or ALT >3 ULN, total bilirubin ≥2 × ULN (for Gilbert’s syndrome, direct bilirubin >ULN is exclusionary) within the past 3 months, or liver function impairment with Class C per Child Pugh classification.
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, including remdesivir, nirmatrelvir/ritonavir, molnupiravir, or mAb treatment (within 30 days or 5 half-lives [whichever is longer] prior to screening), or received convalescent COVID-19 plasma within 12 months. Use of mAb therapy for prevention (eg, pemivibart) of COVID-19 is prohibited within 3 months prior to screening.
9. Current use of any prohibited concomitant medication(s) or unwillingness or inability to use a required concomitant medication(s). Refer to Section 6.9.
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.

Endpoints

Primary and secondary outcome measures (English text)

Primary endpoints 1

1. Proportion of participants with the composite endpoint of: • COVID-19-related emergency department (ED) visits with administration of supplemental oxygen, COVID-19 antiviral, or intravenous (IV) treatment (eg, hydration, antibiotics, or corticosteroids); COVID-19-related hospitalization; or all-cause mortality by Day 38, or • Evidence of recurrent or persistent SARS-CoV-2 infection, [CCI]

Secondary endpoints 10

1. Time to sustained alleviation of all targeted COVID-19 symptoms through Day 38.
2. Proportion of participants with no [CCI]
3. Proportion of participants with evidence of recurrent or persistent SARS-CoV-2 infection, [CCI]
4. Proportion of participants with COVID-19-related ED visits with administration of supplemental oxygen, COVID-19 antiviral, or IV treatment (eg, hydration, antibiotics, or corticosteroids), COVID-19-related hospitalization, or all-cause mortality through Day 38.
5. Change from baseline in SARS-CoV-2 RNA level in NP or nasal swabs over time.
6. Proportion of participants with SARS-CoV-2 NP or nasal RNA< LLOQ at each time point through Day 38.
7. Proportion of participants with viral rebound in SARS-CoV-2 RNA level in NP or nasal swabs through Day 38 visit (in both virologic responders and regardless of virologic response).
8. Time to sustained NP or nasal swab SARS-CoV-2 RNA< LLOQ through Day 38.
9. Incidence of treatment-emergent adverse events (TEAEs).
10. Incidence of serious adverse events (SAEs) and adverse events (AEs) leading to discontinuations.

Investigational products

Investigational medicinal products (IMPs), comparators, placebo, auxiliary

Test 1

Comparator 1

Placebo 2

Sponsors and contacts

Sponsor organisations, regulatory contacts, third parties

Pfizer Inc.

Sponsor organisation

Pfizer Inc.

Address

66 Hudson Boulevard East

City

New York

Postcode

10001-2189

Country

United States

Scientific contact point

Organisation

Pfizer Inc.

Contact name

Clinical Medical Lead

Public contact point

Organisation

Pfizer Inc.

Contact name

Clinical Medical Lead

Third parties 5

Locations

9 EU/EEA countries · 50 investigational sites

By country

Investigational sites

Country notifications

Trial-start, recruitment-start, end and early-termination notifications submitted per Member State

Results and documents

Annex IV summary of results, Annex V layperson summary, and all documents registered in CTIS for this trial

Documents 186 files

Public protocol annexes, IB summaries, regulatory submissions and post-authorisation documents registered in CTIS.

Application history

14 submissions — initial application plus substantial / non-substantial modifications