Trial Outcomes & Findings for PROTECT-APT 1: Early Treatment and Post-Exposure Prophylaxis of COVID-19 (NCT NCT05954286)
NCT ID: NCT05954286
Last Updated: 2026-04-17
Results Overview
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.
Recruitment status
COMPLETED
Study phase
PHASE2
Target enrollment
92 participants
Primary outcome timeframe
Day 0 to Day 28
Results posted on
2026-04-17
Participant Flow
Overall, 135 patients were screened for inclusion under the Master Protocol. Of these, 34 were screen failures and 2 participants were found to be eligible but declined to participate. The remaining 99 were screened for the upamostat PSA eligibility. Of these, 5 patients were screen failures and 2 participants were found to be eligible but declined to participate. 92 participants underwent the step 2 randomization to upamostat or control
Participant milestones
| Measure |
Early Treatment: Upamostat 400 mg
400 mg (2 x 200 mg) capsules administered orally once daily for 14 days
Upamostat: 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.
|
Early Treatment: Placebo Oral Capsule
An identical appearing oral capsules with inactive substance, 2 capsules taken once daily for 14 days Placebo (PO): Oral Capsules
|
|---|---|---|
|
Overall Study
STARTED
|
46
|
46
|
|
Overall Study
COMPLETED
|
46
|
46
|
|
Overall Study
NOT COMPLETED
|
0
|
0
|
Reasons for withdrawal
Withdrawal data not reported
Baseline Characteristics
PROTECT-APT 1: Early Treatment and Post-Exposure Prophylaxis of COVID-19
Baseline characteristics by cohort
| Measure |
Early Treatment: Upamostat 400 mg
n=46 Participants
400 mg (2 x 200 mg) capsules administered orally once daily for 14 days
Upamostat: 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.
|
Early Treatment: Placebo Oral Capsule
n=46 Participants
Identical appearing capsule with inactivate substance. 2 capsules once a day administered orally for 14 days
Placebo (PO): Oral Capsules
|
Total
n=92 Participants
Total of all reporting groups
|
|---|---|---|---|
|
Age, Continuous
|
39.7 years
STANDARD_DEVIATION 12.48 • n=130 Participants
|
35.2 years
STANDARD_DEVIATION 10.12 • n=132 Participants
|
37.5 years
STANDARD_DEVIATION 11.52 • n=130 Participants
|
|
Sex: Female, Male
Female
|
32 Participants
n=130 Participants
|
25 Participants
n=132 Participants
|
57 Participants
n=130 Participants
|
|
Sex: Female, Male
Male
|
14 Participants
n=130 Participants
|
21 Participants
n=132 Participants
|
35 Participants
n=130 Participants
|
|
Ethnicity (NIH/OMB)
Hispanic or Latino
|
0 Participants
n=130 Participants
|
0 Participants
n=132 Participants
|
0 Participants
n=130 Participants
|
|
Ethnicity (NIH/OMB)
Not Hispanic or Latino
|
46 Participants
n=130 Participants
|
46 Participants
n=132 Participants
|
92 Participants
n=130 Participants
|
|
Ethnicity (NIH/OMB)
Unknown or Not Reported
|
0 Participants
n=130 Participants
|
0 Participants
n=132 Participants
|
0 Participants
n=130 Participants
|
|
Race (NIH/OMB)
American Indian or Alaska Native
|
0 Participants
n=130 Participants
|
0 Participants
n=132 Participants
|
0 Participants
n=130 Participants
|
|
Race (NIH/OMB)
Asian
|
33 Participants
n=130 Participants
|
34 Participants
n=132 Participants
|
67 Participants
n=130 Participants
|
|
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
|
0 Participants
n=130 Participants
|
0 Participants
n=132 Participants
|
0 Participants
n=130 Participants
|
|
Race (NIH/OMB)
Black or African American
|
6 Participants
n=130 Participants
|
4 Participants
n=132 Participants
|
10 Participants
n=130 Participants
|
|
Race (NIH/OMB)
White
|
7 Participants
n=130 Participants
|
8 Participants
n=132 Participants
|
15 Participants
n=130 Participants
|
|
Race (NIH/OMB)
More than one race
|
0 Participants
n=130 Participants
|
0 Participants
n=132 Participants
|
0 Participants
n=130 Participants
|
|
Race (NIH/OMB)
Unknown or Not Reported
|
0 Participants
n=130 Participants
|
0 Participants
n=132 Participants
|
0 Participants
n=130 Participants
|
|
Region of Enrollment
United States
|
11 participants
n=130 Participants
|
11 participants
n=132 Participants
|
22 participants
n=130 Participants
|
|
Region of Enrollment
South Africa
|
2 participants
n=130 Participants
|
1 participants
n=132 Participants
|
3 participants
n=130 Participants
|
|
Region of Enrollment
Thailand
|
33 participants
n=130 Participants
|
34 participants
n=132 Participants
|
67 participants
n=130 Participants
|
|
weight (kg)
|
71 kg
STANDARD_DEVIATION 16.8 • n=130 Participants
|
71.8 kg
STANDARD_DEVIATION 16.2 • n=132 Participants
|
71.4 kg
STANDARD_DEVIATION 16.45 • n=130 Participants
|
|
Height (cm)
|
164.1 cm
STANDARD_DEVIATION 9.04 • n=130 Participants
|
167.2 cm
STANDARD_DEVIATION 11.47 • n=132 Participants
|
165.6 cm
STANDARD_DEVIATION 10.4 • n=130 Participants
|
|
COVID vaccination history
|
42 participants receiving COVID vaccination
n=130 Participants
|
44 participants receiving COVID vaccination
n=132 Participants
|
86 participants receiving COVID vaccination
n=130 Participants
|
PRIMARY outcome
Timeframe: Day 0 to Day 28Population: Modified Intention to Treat Population: Defined as all patients that were randomized to upamostat or placebo (step 2 randomization)and receive at least one dose of study medication
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.
Outcome measures
| Measure |
Early Treatment: Upamostat 400 mg
n=46 Participants
400 mg (2 x 200 mg) capsules administered orally once daily for 14 days
Upamostat: 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.
|
Early Treatment: Placebo Oral Capsule
n=46 Participants
Identical appearing capsule with inactive substance administered 2 capsules once a day for 14 days
Placebo (PO): Oral Capsules
|
|---|---|---|
|
Time to Sustained Alleviation or Resolution of COVID-19 Symptoms
|
5.2 days
Standard Deviation 5.02
|
6.1 days
Standard Deviation 5.16
|
SECONDARY outcome
Timeframe: Day 0 to Day 28Population: Modified Intention to Treat
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
Outcome measures
| Measure |
Early Treatment: Upamostat 400 mg
n=46 Participants
400 mg (2 x 200 mg) capsules administered orally once daily for 14 days
Upamostat: 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.
|
Early Treatment: Placebo Oral Capsule
n=46 Participants
Identical appearing capsule with inactive substance administered 2 capsules once a day for 14 days
Placebo (PO): Oral Capsules
|
|---|---|---|
|
Change in Overall COVID-19 Symptom Severity Score
|
2.1 units on a scale (5 point Likert)
Standard Deviation 0.41
|
2.1 units on a scale (5 point Likert)
Standard Deviation 0.38
|
SECONDARY outcome
Timeframe: Day 0 to Week 12Population: Modified Intent to Treat
the time of the first of two consecutive readings below the lower limit of detection
Outcome measures
| Measure |
Early Treatment: Upamostat 400 mg
n=46 Participants
400 mg (2 x 200 mg) capsules administered orally once daily for 14 days
Upamostat: 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.
|
Early Treatment: Placebo Oral Capsule
n=46 Participants
Identical appearing capsule with inactive substance administered 2 capsules once a day for 14 days
Placebo (PO): Oral Capsules
|
|---|---|---|
|
Time to Negative SARS-CoV-2 PCR
|
14.2 days
Standard Deviation 9.2
|
21.8 days
Standard Deviation 19.81
|
SECONDARY outcome
Timeframe: Day 0 to Week 12Population: Modified Intent to Treat
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
Outcome measures
| Measure |
Early Treatment: Upamostat 400 mg
n=46 Participants
400 mg (2 x 200 mg) capsules administered orally once daily for 14 days
Upamostat: 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.
|
Early Treatment: Placebo Oral Capsule
n=46 Participants
Identical appearing capsule with inactive substance administered 2 capsules once a day for 14 days
Placebo (PO): Oral Capsules
|
|---|---|---|
|
Development of New Severe COVID-19 Symptoms
|
8 participants
|
6 participants
|
SECONDARY outcome
Timeframe: Day 0 to Week 12Population: Modified Intent to Treat
Proportion of participants who report a return to usual state of health at Days 7, 14, 28, Week 8, and Week 12
Outcome measures
| Measure |
Early Treatment: Upamostat 400 mg
n=46 Participants
400 mg (2 x 200 mg) capsules administered orally once daily for 14 days
Upamostat: 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.
|
Early Treatment: Placebo Oral Capsule
n=46 Participants
Identical appearing capsule with inactive substance administered 2 capsules once a day for 14 days
Placebo (PO): Oral Capsules
|
|---|---|---|
|
Return to Usual State of Health
Day 7
|
32 participants
|
30 participants
|
|
Return to Usual State of Health
Day 14
|
41 participants
|
40 participants
|
|
Return to Usual State of Health
Day 28
|
46 participants
|
44 participants
|
|
Return to Usual State of Health
Week 8
|
46 participants
|
45 participants
|
|
Return to Usual State of Health
Week 12
|
46 participants
|
45 participants
|
SECONDARY outcome
Timeframe: Day 0 to Week 12Population: MiTT
Proportion of participants who report a return to usual activities at Days 7, 14, 28, Week 8, and Week 12.
Outcome measures
| Measure |
Early Treatment: Upamostat 400 mg
n=46 Participants
400 mg (2 x 200 mg) capsules administered orally once daily for 14 days
Upamostat: 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.
|
Early Treatment: Placebo Oral Capsule
n=46 Participants
Identical appearing capsule with inactive substance administered 2 capsules once a day for 14 days
Placebo (PO): Oral Capsules
|
|---|---|---|
|
Return to Usual Activities
Day 7
|
40 participants
|
39 participants
|
|
Return to Usual Activities
Day 14
|
43 participants
|
45 participants
|
|
Return to Usual Activities
Day 28
|
46 participants
|
45 participants
|
|
Return to Usual Activities
Week 8
|
46 participants
|
46 participants
|
|
Return to Usual Activities
Week 12
|
46 participants
|
46 participants
|
SECONDARY outcome
Timeframe: Day 0 to Week 12Population: MiTT
number of participants hospitalized for any reason
Outcome measures
| Measure |
Early Treatment: Upamostat 400 mg
n=46 Participants
400 mg (2 x 200 mg) capsules administered orally once daily for 14 days
Upamostat: 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.
|
Early Treatment: Placebo Oral Capsule
n=46 Participants
Identical appearing capsule with inactive substance administered 2 capsules once a day for 14 days
Placebo (PO): Oral Capsules
|
|---|---|---|
|
All Cause Hospitalization
|
0 participants
|
0 participants
|
SECONDARY outcome
Timeframe: Day 0 to Week 12Population: MITT
Number of all cause deaths
Outcome measures
| Measure |
Early Treatment: Upamostat 400 mg
n=46 Participants
400 mg (2 x 200 mg) capsules administered orally once daily for 14 days
Upamostat: 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.
|
Early Treatment: Placebo Oral Capsule
n=46 Participants
Identical appearing capsule with inactive substance administered 2 capsules once a day for 14 days
Placebo (PO): Oral Capsules
|
|---|---|---|
|
All Cause Deaths
|
0 Participants
|
0 Participants
|
OTHER_PRE_SPECIFIED outcome
Timeframe: Day 0 to Week 12Population: MITT
number of participants with adverse events resulting in discontinuation of IP
Outcome measures
| Measure |
Early Treatment: Upamostat 400 mg
n=46 Participants
400 mg (2 x 200 mg) capsules administered orally once daily for 14 days
Upamostat: 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.
|
Early Treatment: Placebo Oral Capsule
n=46 Participants
Identical appearing capsule with inactive substance administered 2 capsules once a day for 14 days
Placebo (PO): Oral Capsules
|
|---|---|---|
|
Incidence of AEs Causing IP Discontinuation
|
2 Participants
|
0 Participants
|
POST_HOC outcome
Timeframe: Day 0 to Week 12Population: Post hoc population: Participants were eligible for enrollment if had documentation of a positive molecular or RDT for SARS-CoV-2 within 5 days of enrollment. Nasal swabs were collected prior to administration of first dose of study medication. Quantitative and Qualitative PCR was performed at the central lab (CERBA). Subjects who had a negative PCR at baseline were excluded from this analysis population
Defined as the time of the first of two consecutive readings below the lower limit of detection
Outcome measures
| Measure |
Early Treatment: Upamostat 400 mg
n=26 Participants
400 mg (2 x 200 mg) capsules administered orally once daily for 14 days
Upamostat: 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.
|
Early Treatment: Placebo Oral Capsule
n=24 Participants
Identical appearing capsule with inactive substance administered 2 capsules once a day for 14 days
Placebo (PO): Oral Capsules
|
|---|---|---|
|
Time to Negative PCR
|
14.2 days
Standard Deviation 9.02
|
21.8 days
Standard Deviation 19.81
|
Adverse Events
Early Treatment: Upamostat 400 mg
Serious events: 0 serious events
Other events: 4 other events
Deaths: 0 deaths
Early Treatment: Placebo Oral Capsule
Serious events: 0 serious events
Other events: 0 other events
Deaths: 0 deaths
Serious adverse events
Adverse event data not reported
Other adverse events
| Measure |
Early Treatment: Upamostat 400 mg
n=46 participants at risk
400 mg (2 x 200 mg) capsules administered orally once daily for 14 days
Upamostat: 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.
|
Early Treatment: Placebo Oral Capsule
n=46 participants at risk
Identical appearing capsule with inactivate substance. 2 capsules once a day administered orally for 14 days
Placebo (PO): Oral Capsules
|
|---|---|---|
|
Skin and subcutaneous tissue disorders
Hypersensitivity Reaction
|
4.3%
2/46 • Number of events 2 • 12 weeks
Standard clinicaltrials.gov definitions applied with DAIDS Table for Grading the Severity of Adult and Pediatric Adverse Events (DAIDS AE Grading Table) corrected Version 2.1, July 2017 for grading
|
0.00%
0/46 • 12 weeks
Standard clinicaltrials.gov definitions applied with DAIDS Table for Grading the Severity of Adult and Pediatric Adverse Events (DAIDS AE Grading Table) corrected Version 2.1, July 2017 for grading
|
|
Renal and urinary disorders
Renal Laboratory Abnormality
|
4.3%
2/46 • Number of events 2 • 12 weeks
Standard clinicaltrials.gov definitions applied with DAIDS Table for Grading the Severity of Adult and Pediatric Adverse Events (DAIDS AE Grading Table) corrected Version 2.1, July 2017 for grading
|
0.00%
0/46 • 12 weeks
Standard clinicaltrials.gov definitions applied with DAIDS Table for Grading the Severity of Adult and Pediatric Adverse Events (DAIDS AE Grading Table) corrected Version 2.1, July 2017 for grading
|
Additional Information
Dr. Kristen Pettrone
Henry Jackson Foundation for the Advancement of Military Medicine
Phone: (240) 694-2000
Email: [email protected]
Results disclosure agreements
- Principal investigator is a sponsor employee
- Publication restrictions are in place