A Study to Learn About the Study Medicine (Nirmatrelvir Plus Ritonavir) in Pregnant Women With COVID-19
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Phase
Phase 1
Status
Terminated
Study type
Interventional
Design
Non randomized · None · Treatment
Enrollment
25actual
Sites
13
Country
United States
Every value on this page is a field the sponsor filed with ClinicalTrials.gov, reproduced. Dates are their own estimates, revised as a study runs, unless the registry marks them actual. sources →
Source: ClinicalTrials.gov, retrieved 2026-08-19
Why the sponsor stopped it
The trial prematurely terminated due to the inability to recruit the planned number of subjects. The decision to terminate the trial was not based on any safety concerns.
As filed on the registry record, in the sponsor's own words.
Dates
each axis at the precision it was filed, with the registry's own basis| Date | Filed | Basis | What it is |
|---|---|---|---|
| Start | 2022-06-22 | actual | When the study began enrolling |
| Primary completion | 2025-03-26 | actual | The date the last participant is measured for the primary outcome — the readout window |
| Study completion | 2025-05-13 | actual | The whole study's end, after follow-up |
| First posted | 2022-05-23 | actual | When this record first appeared on the registry |
| Results posted | — | When the sponsor posted results to the registry | |
| Record updated | 2026-08-17 | actual | The sponsor's own last edit to this record — every projection above is as current as this date |
What it studies
Condition
- COVID-19
Interventions
- Drug: nirmatrelvir — also filed as PF-07321332
- Drug: ritonavir
Primary outcomes
what the primary-completion date above is the date OFApparent Oral Clearance (CL/F)
measured Day 1: 1-3 hour post-dose; Day 3: 4-8 hour post-dose; Day 4: 8 to less than 12 hour post dose; Day 5: 2-4 hour, 6-8 hour, 10 to less than 12 hour post dose.
Apparent Volume of Distribution (Vz/F)
measured Day 1: 1-3 hour post-dose; Day 3: 4-8 hour post-dose; Day 4: 8 to less than 12 hour post dose; Day 5: 2-4 hour, 6-8 hour, 10 to less than 12 hour post dose.
Area Under the Curve From Time Zero to End of Dosing Interval (AUCtau)
measured Day 1: 1-3 hour post-dose; Day 3: 4-8 hour post-dose; Day 4: 8 to less than 12 hour post dose; Day 5: 2-4 hour, 6-8 hour, 10 to less than 12 hour post dose.
Maximum Observed Plasma Concentration (Cmax)
measured Day 1: 1-3 hour post-dose; Day 3: 4-8 hour post-dose; Day 4: 8 to less than 12 hour post dose; Day 5: 2-4 hour, 6-8 hour, 10 to less than 12 hour post dose.
Plasma Decay Half-Life (t1/2)
measured Day 1: 1-3 hour post-dose; Day 3: 4-8 hour post-dose; Day 4: 8 to less than 12 hour post dose; Day 5: 2-4 hour, 6-8 hour, 10 to less than 12 hour post dose.
Observed Plasma Trough Concentration (Ctrough)
measured Day 1: 1-3 hour post-dose; Day 3: 4-8 hour post-dose; Day 4: 8 to less than 12 hour post dose; Day 5: 2-4 hour, 6-8 hour, 10 to less than 12 hour post dose.
Incidence of Treatment Emergent Adverse Events (TEAEs)
measured Baseline up through Day 34
Incidence of TEAEs, SAEs, and AEs leading to discontinuations
measured Baseline up through end of treatment (Day 5/Day 6)
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