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CompletedNCT05954286PROTECT-APT 1Updated Apr 17, 2026Results posted

PROTECT-APT 1: Early Treatment and Post-Exposure Prophylaxis of COVID-19

A Phase 2 interventional study of Upamostat and Placebo (PO) in SARS-CoV-2, sponsored by Henry M. Jackson Foundation for the Advancement of Military Medicine. Completed at 6 sites in 4 countries. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-04-17.

Sponsored by Henry M. Jackson Foundation for the Advancement of Military Medicine · Phase 2, Interventional, and Prevention

Phase
Phase 2
Study type
Interventional
Enrollment
92
Allocation
Randomized
Ages
18 Years and older
Sex
All
01

Study summary

This study is an adaptive, randomized, double blind, platform trial evaluating promising investigational products (IP) for safety and efficacy as early outpatient treatment and post-exposure prophylaxis for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2).

Read the detailed description

This multicenter trial will be conducted in both domestic and international sites. The study will compare IPs to control in standard and intermediate risk, non-hospitalized adult SARS-CoV-2 infected participants and uninfected adult contacts of SARS-CoV-2 confirmed cases. The master protocol will outline the core elements of the study. Investigational products may be included in either or both study indications: early treatment and post-exposure prophylaxis (PEP). The study includes a phase 2 evaluation for all IPs. The platform trial design will allow for multiple IPs to be incorporated into the protocol as product specific appendices (PSA) as products are identified and become available. Each PSA will detail the interventions, the endpoints, target treatment effect, intended statistical analysis, the relevant control arms, and the sample size range. The PSA may define additional adaptive design elements, such as early declaration rules.

02

Conditions studied

  • SARS-CoV-2

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Keywords

  • COVID-19
  • Early Treatment
  • Post-Exposure Prophylaxis
  • Outpatient
03

In context

COVID-19

7,640 studies on the registry are indexed under COVID-19; 488 are open to participants now.

This study's enrollment of 92 is close to the median of 100 across 4,099 interventional studies indexed under COVID-19.

Browse COVID-19 studies →

Lead sponsor

Henry M. Jackson Foundation for the Advancement of Military Medicine is the lead sponsor of 84 studies on the registry; 18 are open to participants now.

Of its 6 completed or terminated interventional studies of FDA-regulated products, 1 (17%) have results posted.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years and older
Sexes eligible
All
Accepts healthy volunteers
Yes

Eligibility criteria

Population A: Symptomatic adults seeking care or testing for COVID-19

Inclusion Criteria:

  1. Age ≥ 18 years
  2. Positive molecular or antigen diagnostic test for SARS-CoV-2 at study enrollment or within ≤ 5 days prior to enrollment
  3. Presence of two or more Screening Symptoms listed in Supplement 3 with at least two symptoms classified as moderate to severe (and/or ≥ 2 on the frequency questions or loss of taste/smell questions) at the time of enrollment a. For participants who have preexisting conditions causing mild or moderate symptoms listed on the Screening Symptom Questionnaire, there must be an increase of at least one severity level for that symptom at enrollment (For example, prior to illness participant routinely experienced headaches rated as moderate severity, now rating headache as severe at enrollment)

    • Supplement 3 Screening Symptoms: stuffy or runny nose, hoarse voice, sore throat, difficulty breathing, cough, fatigue (low energy or tiredness), muscle or body aches, headache, fever (documented temperature > 38° C [100.4° F]) or subjective fever, chills or shivering, feeling hot or feverish, nausea, vomiting, diarrhea, loss of smell, loss of taste
  4. Symptom onset ≤ 5 days prior to enrollment

Exclusion Criteria:

  1. Hospital admission at the time of enrollment
  2. Hospitalization will be defined as requiring medical care not available in an outpatient setting for greater than 24 hours
  3. Hospitalization for isolation or quarantine requirements or for social reasons will NOT constitute an exclusion criterion
  4. Laboratory confirmed SARS-CoV-2 infection 6 to 90 days prior to enrollment
  5. Oxygen saturation \< 92% on room air
  6. Baseline use of supplemental oxygen at the time of enrollment
  7. Presence of any of the following comorbidities that per the PI puts the patient at high risk of developing severe COVID-19 illness:

    a. Age ≥ 75 years b. Active treatment for solid tumor and hematologic malignancies c. Hematologic malignancy, myeloma, or related disorder (e.g., myelodysplastic syndrome, myelofibrosis) d. Receipt of solid-organ transplant or an islet transplant and taking immunosuppressive therapy e. Chemotherapy or radiotherapy for solid organ cancer in the last 12 months f. Receipt of chimeric antigen receptor (CAR)-T-cell therapy or hematopoietic stem cell transplant (within 2 years of transplantation or taking immunosuppressive therapy) g. Moderate or severe primary immunodeficiency (e.g., common variable immunodeficiency disease, severe combined immunodeficiency, DiGeorge syndrome, Wiskott-Aldrich syndrome) h. Advanced or untreated HIV infection (people with HIV and CD4 cell counts less than 200/mm3, history of an AIDS-defining illness without immune reconstitution, or clinical manifestations of symptomatic HIV) i. Active treatment with high-dose corticosteroids (i.e., 20 or more mg of prednisone or equivalent per day when administered for 2 or more weeks), alkylating agents, antimetabolites, transplant-related immunosuppressive drugs, cancer chemotherapeutic agents classified as severely immunosuppressive, tumor necrosis factor (TNF) blockers, and other biologic agents that are immunosuppressive or immunomodulatory j. Sickle cell disease k. Chronic liver disease (e.g., Child-Pugh Class A, B or C cirrhosis) l. Down syndrome m. Dementia or neurocognitive disability (e.g., Parkinson's disease) n. Participants with 3 or more of the following conditions: i) No prior COVID-19 infection OR has not completed a COVID-19 vaccine series within the last 6 months OR has not received a vaccine booster within the last 6 months ii) Age 65-74 years iii) BMI ≥35 (or >95th percentile in adolescents) iv) Type 1 or type 2 diabetes mellitus v) Cardiovascular disease (including HTN if age >55) vi) Chronic lung disease (including bronchiectasis, CF, COPD, ILD, PHTN, PE, moderate-to-severe asthma) vii) Chronic kidney disease (eGFR \<30)

  8. Participants who are receiving or plan to receive anti-SARS-CoV-2 antivirals for treatment of their COVID-19

Population B: Uninfected adult contacts of symptomatic SARS-CoV-2 infected individuals

Inclusion Criteria:

  1. Age ≥ 18 years
  2. Asymptomatic contact of an individual with laboratory confirmed SARS-CoV-2 infection defined as:

    a. Indoor exposure to the symptomatic case or cases within 6 feet (2 meters) for ≥ 15 minutes over a 24-hour period without the use of personal protective equipment

  3. Negative screening SARS-CoV-2 molecular or antigen diagnostic test performed at screening or within less than or equal to 24 hours of enrollment
  4. Exposure and enrollment within 6 days or less from when the symptomatic, confirmed SARS-CoV-2 positive case first had symptoms

Exclusion Criteria:

1. Symptoms attributed to COVID-19 as assessed by the investigator 2. Positive molecular or antigen diagnostic test for SARS-CoV-2 from any upper respiratory specimen within 90 days prior to enrollment 3. SARS-CoV-2 vaccination within 90 days prior to enrollment EXCEPT if severely immunocompromised or a known vaccine non-responder 4. Severely immunocompromised or a known vaccine non-responder defined as: solid organ or stem cell transplant recipient, B cell leukemia, receiving B cell depletion therapy (e.g., rituximab), agammaglobulinemia, or negative serology ≥2 weeks after vaccination with two doses of a vaccine 5. Hospital admission at the time of enrollment

  1. Hospitalization will be defined as requiring medical care not available in an outpatient setting for greater than 24 hours 6. Hospitalization for isolation or quarantine requirements or for social reasons will NOT constitute an exclusion criterion

    For Both populations:

    Inclusion Criteria:

    1. Must also meet the intervention specific inclusion/exclusion criteria for at least one PSA that is enrolling participants

    Exclusion Criteria:

    1. Absence of informed consent
    2. Pregnancy
    3. Breastfeeding
    4. Individuals who the study investigators believe are unable to comply with the requirements of the study
    5. Participation in another intervention trial for the treatment or prophylaxis of SARS-CoV-2 infection or COVID-19 disease at the time of enrollment

    Additional Criteria for the Early Treatment Upamostat Arm:

    Inclusion Criteria:

    1. Women of childbearing potential must agree to use an effective contraceptive method upon enrollment in the study through 8 weeks after the last dose of the investigational product. This would include oral contraceptives, implanted contraceptives, intrauterine devices, and barrier methods.

    - A woman is considered of childbearing potential unless post-menopausal (subject is at least 50 years old and has a history of ≥ 2 years without menses without other known or suspected cause), or permanently surgically sterilized.

    • Participants not of reproductive potential are eligible without requiring the use of a contraceptive method. Participant-reported history is acceptable documentation of surgical sterilization and menopause.

    Exclusion Criteria:

    1. Patient is currently taking or is expected to start taking warfarin, apixaban (Eliquis), or rivaroxaban (Xarelto). Patients may be taking or start on study dabigatran (Pradaxa), standard or low molecular weight heparin.

    2. Patients with prolonged QT/QTc interval and/or increased susceptibility to arrythmia defined as the presence of any of the following:

    - QTc interval > 450 msec

    - Pathological Q-waves (defined as Q-wave > 40 msec or depth > 0.4-0.5 mV)

    - Evidence of ventricular pre-excitation

    - Electrocardiographic evidence of complete LBBB, RBBB, incomplete LBBB, in complete RBBB

    - Evidence of second- or third-degree heart block

    • Intraventricular conduction delay with QRS duration > 120 msec
    • Bradycardia as defined by sinus rate\< 50 bpm
    • Personal or family history of long QT syndrome
    • Personal history of cardiac disease, symptomatic or asymptomatic arrhythmias, except for sinus arrhythmia
    • Syncopal episodes or additional risk factors for torsades de points (e.g., heart failure, hypokalemia)
05

Study design

Phase
Phase 2
Primary purpose
Prevention
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Triple (Participant, Care provider, Investigator)
Enrollment
92 participants (actual)

Study arms

  • Experimental
    Early Treatment: Upamostat 400 mg

    400 mg (2 x 200 mg) capsules administered orally once daily for 14 days

    Drug: Upamostat

  • Placebo comparator
    Early Treatment: Placebo Oral Capsule

    The placebo arm may be pooled across more than one experimental arm if multiple investigational drug are available to be tested at the same time and administered in the same way.

    Drug: Placebo (PO)

Interventions

  • DrugUpamostat

    Upamostat is available as a hydrogen sulphate salt (also designated as WX-671.1). WX-671.1 is a white to yellowish powder which is freely soluble in dimethyl sulfoxide and soluble in ethanol. The drug substance is very slightly soluble in water or 0.1 M HCl.

    Also known as: WX-671, RHB-107

  • DrugPlacebo (PO)

    Oral Capsules

06

What researchers measure

Primary outcomes

  1. Time to Sustained Alleviation or Resolution of COVID-19 Symptoms

    Defined as the number of days from randomization within a PSA to the first day the participant reports all symptoms as mild or none for at least 3 consecutive days. Symptoms will be assessed via completion of a Screening Symptom Questionnaire at Enrollment and then a Daily Follow Up Symptom Questionnaire.

    Time frame: Day 0 to Day 28

Secondary outcomes

  1. Change in Overall COVID-19 Symptom Severity Score

    Participants complete a Daily Symptom Follow Up Questionnaire on Days 1 through 28 and then at follow up visits. Symptoms are reported on a 4-point scale (0=none, 1=mild, 2=moderate, 3=severe). Symptoms assessed include nasal congestion, sore throat, hoarse voice, shortness of breath, cough, fatigue, myalgias, headache, chills, fever, nausea or vomiting, change in taste and change in smell. An additional question assesses overall symptom severity on the same 4 point scale

    Time frame: Day 0 to Day 28

  2. Time to Negative SARS-CoV-2 PCR

    the time of the first of two consecutive readings below the lower limit of detection

    Time frame: Day 0 to Week 12

  3. Development of New Severe COVID-19 Symptoms

    Proportion of participants in each treatment group developing new COVID-19 symptoms on the Daily Symptom Questionnaire rated as severe from Day 0 to Day 28

    Time frame: Day 0 to Week 12

  4. Return to Usual State of Health

    Proportion of participants who report a return to usual state of health at Days 7, 14, 28, Week 8, and Week 12

    Time frame: Day 0 to Week 12

  5. Return to Usual Activities

    Proportion of participants who report a return to usual activities at Days 7, 14, 28, Week 8, and Week 12.

    Time frame: Day 0 to Week 12

  6. All Cause Hospitalization

    number of participants hospitalized for any reason

    Time frame: Day 0 to Week 12

  7. All Cause Deaths

    Number of all cause deaths

    Time frame: Day 0 to Week 12

Other outcomes

  1. Incidence of AEs Causing IP Discontinuation

    number of participants with adverse events resulting in discontinuation of IP

    Time frame: Day 0 to Week 12

07

Results

Posted Feb 13, 2026

Participant flow

Participant flow — Overall Study
MilestoneEarly Treatment: Upamostat 400 mgEarly Treatment: Placebo Oral Capsule
Started4646
Completed4646
Not completed00

Outcome measures

PrimaryTime to Sustained Alleviation or Resolution of COVID-19 Symptoms

Defined as the number of days from randomization within a PSA to the first day the participant reports all symptoms as mild or none for at least 3 consecutive days. Symptoms will be assessed via completion of a Screening Symptom Questionnaire at Enrollment and then a Daily Follow Up Symptom Questionnaire.

Time frame:
Day 0 to Day 28
Reported as:
Mean · days
Time to Sustained Alleviation or Resolution of COVID-19 Symptoms
daysEarly Treatment: Upamostat 400 mgEarly Treatment: Placebo Oral Capsule
Time to Sustained Alleviation or Resolution of COVID-19 Symptoms5.2 ± 5.026.1 ± 5.16
SecondaryChange in Overall COVID-19 Symptom Severity Score

Participants complete a Daily Symptom Follow Up Questionnaire on Days 1 through 28 and then at follow up visits. Symptoms are reported on a 4-point scale (0=none, 1=mild, 2=moderate, 3=severe). Symptoms assessed include nasal congestion, sore throat, hoarse voice, shortness of breath, cough, fatigue, myalgias, headache, chills, fever, nausea or vomiting, change in taste and change in smell. An additional question assesses overall symptom severity on the same 4 point scale

Time frame:
Day 0 to Day 28
Reported as:
Mean · units on a scale (5 point Likert)
Change in Overall COVID-19 Symptom Severity Score
units on a scale (5 point Likert)Early Treatment: Upamostat 400 mgEarly Treatment: Placebo Oral Capsule
Change in Overall COVID-19 Symptom Severity Score2.1 ± 0.412.1 ± 0.38
SecondaryTime to Negative SARS-CoV-2 PCR

the time of the first of two consecutive readings below the lower limit of detection

Time frame:
Day 0 to Week 12
Reported as:
Mean · days
Time to Negative SARS-CoV-2 PCR
daysEarly Treatment: Upamostat 400 mgEarly Treatment: Placebo Oral Capsule
Time to Negative SARS-CoV-2 PCR14.2 ± 9.221.8 ± 19.81
SecondaryDevelopment of New Severe COVID-19 Symptoms

Proportion of participants in each treatment group developing new COVID-19 symptoms on the Daily Symptom Questionnaire rated as severe from Day 0 to Day 28

Time frame:
Day 0 to Week 12
Reported as:
Number · participants
Development of New Severe COVID-19 Symptoms
participantsEarly Treatment: Upamostat 400 mgEarly Treatment: Placebo Oral Capsule
Development of New Severe COVID-19 Symptoms86
SecondaryReturn to Usual State of Health

Proportion of participants who report a return to usual state of health at Days 7, 14, 28, Week 8, and Week 12

Time frame:
Day 0 to Week 12
Reported as:
Number · participants
Return to Usual State of Health
participantsEarly Treatment: Upamostat 400 mgEarly Treatment: Placebo Oral Capsule
Day 73230
Day 144140
Day 284644
Week 84645
Week 124645
SecondaryReturn to Usual Activities

Proportion of participants who report a return to usual activities at Days 7, 14, 28, Week 8, and Week 12.

Time frame:
Day 0 to Week 12
Reported as:
Number · participants
Return to Usual Activities
participantsEarly Treatment: Upamostat 400 mgEarly Treatment: Placebo Oral Capsule
Day 74039
Day 144345
Day 284645
Week 84646
Week 124646
SecondaryAll Cause Hospitalization

number of participants hospitalized for any reason

Time frame:
Day 0 to Week 12
Reported as:
Number · participants
All Cause Hospitalization
participantsEarly Treatment: Upamostat 400 mgEarly Treatment: Placebo Oral Capsule
All Cause Hospitalization00
SecondaryAll Cause Deaths

Number of all cause deaths

Time frame:
Day 0 to Week 12
Reported as:
Count of participants · Participants
All Cause Deaths
ParticipantsEarly Treatment: Upamostat 400 mgEarly Treatment: Placebo Oral Capsule
All Cause Deaths00
Other pre-specifiedIncidence of AEs Causing IP Discontinuation

number of participants with adverse events resulting in discontinuation of IP

Time frame:
Day 0 to Week 12
Reported as:
Count of participants · Participants
Incidence of AEs Causing IP Discontinuation
ParticipantsEarly Treatment: Upamostat 400 mgEarly Treatment: Placebo Oral Capsule
Incidence of AEs Causing IP Discontinuation20
Post-hocTime to Negative PCR

Defined as the time of the first of two consecutive readings below the lower limit of detection

Time frame:
Day 0 to Week 12
Reported as:
Mean · days
Time to Negative PCR
daysUpamostat: Baseline Positive PCRPlacebo: Baseline Positive PCR
Time to Negative PCR14.2 ± 9.0221.8 ± 19.81

Adverse events

Collected over 12 weeks. Non-serious events are listed at a 0% frequency threshold.

Adverse event summary by group
GroupDeathsSeriousOther
Early Treatment: Upamostat 400 mg0/46 (0%)0/46 (0%)4/46 (8.7%)
Early Treatment: Placebo Oral Capsule0/46 (0%)0/46 (0%)0/46 (0%)
Most frequent other events
Most frequent other events
EventEarly Treatment: Upamostat 400 mgEarly Treatment: Placebo Oral Capsule
Hypersensitivity ReactionSkin and subcutaneous tissue disorders2/460/46
Renal Laboratory AbnormalityRenal and urinary disorders2/460/46

Baseline characteristics

All participants that completed step 2 randomization and received a single dose of upamostat or placebo completed the study.

Age, Continuous
Age, Continuous(years)Early Treatment: Upamostat 400 mgEarly Treatment: Placebo Oral CapsuleTotal
Mean39.7 ± 12.4835.2 ± 10.1237.5 ± 11.52
Sex: Female, Male
Sex: Female, Male(Participants)Early Treatment: Upamostat 400 mgEarly Treatment: Placebo Oral CapsuleTotal
Female322557
Male142135
Ethnicity (NIH/OMB)
Ethnicity (NIH/OMB)(Participants)Early Treatment: Upamostat 400 mgEarly Treatment: Placebo Oral CapsuleTotal
Hispanic or Latino000
Not Hispanic or Latino464692
Unknown or Not Reported000
Race (NIH/OMB)
Race (NIH/OMB)(Participants)Early Treatment: Upamostat 400 mgEarly Treatment: Placebo Oral CapsuleTotal
American Indian or Alaska Native000
Asian333467
Native Hawaiian or Other Pacific Islander000
Black or African American6410
White7815
More than one race000
Unknown or Not Reported000
Region of Enrollment
Region of Enrollment(participants)Early Treatment: Upamostat 400 mgEarly Treatment: Placebo Oral CapsuleTotal
United States111122
South Africa213
Thailand333467
weight (kg)
weight (kg)(kg)Early Treatment: Upamostat 400 mgEarly Treatment: Placebo Oral CapsuleTotal
Mean71 ± 16.871.8 ± 16.271.4 ± 16.45
Height (cm)
Height (cm)(cm)Early Treatment: Upamostat 400 mgEarly Treatment: Placebo Oral CapsuleTotal
Mean164.1 ± 9.04167.2 ± 11.47165.6 ± 10.4
COVID vaccination history
COVID vaccination history(participants receiving COVID vaccination)Early Treatment: Upamostat 400 mgEarly Treatment: Placebo Oral CapsuleTotal
Number424486
08

Study locations

6 sites
  • Johns Hopkins Hospital
    Baltimore, Maryland 21287, United States
  • University Hospitals Cleveland Medical Center
    Cleveland, Ohio 44106, United States
  • KUR Research
    Nashville, Tennessee 37209, United States
  • Josha Research
    Bloemfontein, 9300, South Africa
  • Royal Thai Army Clinical Research Center (RTA CRC) Royal Thai Army-Armed Forces Research Institute of Medical Sciences (RTA-AFRIMS)
    Bangkok, 10400, Thailand
  • Makerere University Walter Reed Project
    Fort Portal, Uganda
09

References and documents

Study documents

  • Study protocol · Feb 7, 2024
  • Study protocol · Feb 7, 2024
  • Statistical analysis plan · Jul 28, 2025
  • Informed consent form · Mar 14, 2024
  • Informed consent form · Mar 14, 2024

Documents are hosted by the registry — open the source record to download them.

Individual participant data

Plan to share: Undecided

10

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Apr 17, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
11

Registry details

Key details

Study ID
NCT05954286
Lead sponsor
Henry M. Jackson Foundation for the Advancement of Military Medicine
Collaborators
Joint Program Executive Office Chemical, Biological, Radiological, and Nuclear Defense Enabling Biotechnologies, RedHill Biopharma Limited, FHI Clinical, Inc.
Responsible party
Sponsor
First posted
Jul 20, 2023
Start date
Jan 29, 2024
Primary completion
Apr 24, 2025
Completion
Apr 24, 2025
Results posted
Feb 13, 2026
Last update
Apr 17, 2026

Oversight

Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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