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A Study to Learn About the Study Medicine (Nirmatrelvir Plus Ritonavir) in Pregnant Women With COVID-19

A PHASE 1, OPEN-LABEL STUDY TO EVALUATE THE PHARMACOKINETICS, SAFETY, AND TOLERABILITY OF ORALLY ADMINISTERED NIRMATRELVIR/RITONAVIR IN PREGNANT WOMEN WITH MILD-TO-MODERATE COVID-19

Status
Terminated
Phases
Phase 1
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT05386472
Enrollment
25
Registered
2022-05-23
Start date
2022-06-22
Completion date
2025-05-12
Last updated
2025-07-29

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

COVID-19

Keywords

Severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2), Pregnancy, Paxlovid, Nirmatrelvir

Brief summary

The purpose of this clinical trial is to learn about how study medicine (Paxlovid, which contains nirmatrelvir and ritonavir) is changed and eliminated from the body, as well as its safety, and the extent to which side effects can be tolerated for treatment of pregnant women with mild or moderate COVID-19 compared to non-pregnant women with mild or moderate COVID-19. This study is seeking participants who: * are expecting a healthy baby and are in their second or third trimester pregnancy and have mild or moderate COVID-19 * are not pregnant and have mild or moderate COVID-19. All participants in this study will take Paxlovid by mouth every 12 hours for 5 days. We will study the experiences of people receiving the study medicine. This will help us decide if the study medicine is safe. All participants will take part in this study for at least 34 days; pregnant participants will take part until their delivery, so that the study duration may be up to 6 months, depending on their delivery date. During this time, participants will have 7to 8 visits and, if pregnant, a visit at delivery. Around 2 to 3 visits and the delivery visit will be done in person (at the clinic or at the participant's home). The other 5 visits may be done over the phone, unless in-person visit is necessary as decided by the doctor. Blood samples will be collected on the first 4 to 5 study visits (and at other study visits, if necessary).

Interventions

Nirmatrelvir (tablets) administered by mouth every 12 hours for 5 days (10 doses total)

DRUGritonavir

Ritonavir (capsules) administered by mouth every 12 hours for 5 days (10 doses total)

Sponsors

Pfizer
Lead SponsorINDUSTRY

Study design

Allocation
NON_RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE

Masking description

(Open Label)

Eligibility

Sex/Gender
FEMALE
Age
18 Years to 50 Years
Healthy volunteers
No

Inclusion criteria

* All cohorts: Mild-to-moderate COVID-19 infection confirmed in sample collected ≤5 days prior to enrollment; onset within 5 days prior to enrollment and presence of ≥1 sign/symptom on the day of enrollment. * Cohorts 1&2: Expecting single baby; Pregnant in 2nd trimester, 14 0/7 to 27 6/7 weeks of gestational age (Cohort 1) or 3rd trimester, ≥28 0/7 and ≤34 6/7 weeks of gestational age (Cohort 2), by ultrasound. * All cohorts: Otherwise healthy participants who are determined by medical history, physical examination, and clinical judgment to be appropriate for inclusion in the study

Exclusion criteria

* All cohorts: Current need for hospitalization or anticipated need for hospitalization in the clinical opinion of the site investigator. * Cohorts 1&2: Prior/current major condition or illness of mother/fetus substantially increasing risk of study participation/completion or impacting pregnancy/fetal outcomes in investigator's judgement. * All cohorts: Current use of any medications that are highly dependent on CYP3A4 for clearance, and which are contraindicated in combination with nirmatrelvir/ritonavir. * All cohorts: Has received or is expected to receive monoclonal antibody treatment, convalescent COVID-19 plasma, or anti-viral treatment (eg, molnupiravir) for the current SARSCoV-2 infection. * All cohorts: Participants with moderate to severe kidney impairment

Design outcomes

Primary

MeasureTime frame
Apparent Oral Clearance (CL/F)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)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)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)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)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)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)Baseline up through Day 34
Incidence of TEAEs, SAEs, and AEs leading to discontinuationsBaseline up through end of treatment (Day 5/Day 6)

Secondary

MeasureTime frame
Number of participants with stillbirthsAt delivery of the baby
Number of participants with spontaneous abortionsAt delivery of the baby
Number of participants with induced/elective abortionsAt delivery of the baby
Number of participants with unknown deliveryAt delivery of the baby
Number of aborted or stillborn fetuses with abnormal findings upon gross visual inspectionAt delivery of the baby
Number of participants with delivery at medical facilityAt delivery of the baby
Number of neonates with congenital malformation/anomaly or other neonatal problemAt birth
Body weight of newborn infantsAt birth
Body length of newborn infantsAt birth
Head circumference of newborn infantsAt birth
Incidence of SAEs in newborn infantsBirth through 24 hours after birth or until Study Day 34 (whichever is later)
Gestational age of newborn infantsAt birth
Number of participants with delivery at homeAt delivery of the baby
Number of participants with delivery at other locationAt delivery of the baby
Number of participants with caesarean section deliveryAt delivery of the baby
Number of participants with vaginal deliveryAt delivery of the baby
Number of participants with complications during deliveryAt delivery of the baby
Number of full-term live deliveriesAt delivery of the baby
Number of premature live deliveriesAt delivery of the baby

Countries

United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026