Excretion of Rivaroxaban in Human Breast Milk

Phase 1

Recruiting

• Conditions: Postpartum; VTE Prophylaxis; VTE (Venous Thromboembolism); Rivaroxaban; Breastfeeding; Breast Milk Collection
• Interventions: Drug: Rivaroxaban 10 MG Oral Tablet; Drug: Rivaroxaban 20 MG Oral Tablet

• Registration Number: NCT06831474
• Lead Sponsor: Thomas Jefferson University

Brief Summary

The purpose of this study is to investigate the distribution of rivaroxaban into human milk at both therapeutic and prophylactic doses, and over time with repeated dosing.

Detailed Description

The aim of our study is to perform a phase 1, single arm clinical trial to investigate the distribution of rivaroxaban into human milk at both therapeutic and prophylactic maternal doses. Our goal is to enhance the limited, although positive, data regarding the safety of rivaroxaban in breastfeeding. Our novel contributions to the existing body of literature will be in our investigation of rivaroxaban at both prophylactic and therapeutic doses, in repeated doses over time, and in a larger sample of participants. These results will provide physicians and national societies with safety data needed to properly counsel patients and advance clinical guidelines for postpartum care.

Study Timeline

• Study First Submitted: 2025-02-12
• Study First Submitted QC: 2025-02-12
• Study First Posted: 2025-02-18
• Status Verified: 2025-07
• Study Start: 2025-07-01
• Last Update Submitted: 2025-07-14
• Last Update Posted: 2025-07-17
• Primary Completion: 2026-04-01
• Study Completion: 2026-07-31

Recruitment & Eligibility

• Status: RECRUITING
• Sex: Female
• Target Recruitment: 10

Inclusion Criteria

1. Postpartum within 6 weeks of delivery
2. Greater than 18 years old at expected date of delivery
3. English speaking
4. Hemodynamically stable without concern for ongoing blood loss
5. Non-breastfeeding
6. Or breastfeeding an infant born at or equal to 37 weeks' gestation, weighing >2600g at birth and is not requiring intensive care
7. Meet inclusion criteria for prophylactic rivaroxaban dose: pre-pregnancy BMI >/= 40 and/or any personal history of VTE. Or >/= 2 of the following: pre-pregnancy BMI 30-39, immobility, pregnancy complications, cesarean delivery, hysterectomy
8. Or meet inclusion criteria for therapeutic rivaroxaban dose: have an indication for therapeutic anticoagulation per the American College of Obstetricians and Gynecologists' (ACOG) practice bulletin #196, or other indication per their primary team, and recommended for such anticoagulation per their primary practitioner.

Exclusion Criteria

1. Pregnant
2. Less than 18 years old at estimated date of delivery
3. Hemodynamic instability and/or concern for ongoing blood loss
4. Newly diagnosed deep vein thrombosis (DVT) or pulmonary embolism (PE) in the postpartum period
5. Abnormal maternal renal or liver function (creatinine clearance < 30 mL/min and/or liver function tests greater than lab normal)
6. A contraindication to rivaroxaban: hypersensitivity to rivaroxaban; active pathological bleeding
7. Breastfeeding an infant admitted to neonatal intensive care unit, infant gestational age at birth <37w0d or weighing <2600g.
8. If all of the following are met: age less than 40, ambulating, body mass index (BMI) less than 30, no active history of malignancy.
9. If patient lacks indication for therapeutic anticoagulation in the postpartum period per the American College of Obstetricians and Gynecologists' (ACOG) practice bulletin #196

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Prophylactic rivaroxaban	Rivaroxaban 10 MG Oral Tablet	Patients will receive 10 mg daily of rivaroxaban starting by the first postpartum day. The medication will be ordered by their postpartum physician team through the inpatient pharmacy and dispensed by their inpatient nursing team, as per standard of care. The decision for dose 10 mg vs 20 mg of rivaroxaban is based on inclusion criteria and patient's physician team's recommendation for prophylactic (10 mg) vs. therapeutic (20 mg) dosing.
Therapeutic or Intermediate dose rivaroxaban	Rivaroxaban 20 MG Oral Tablet	Patients will receive 20 mg daily of rivaroxaban starting by the first postpartum day. The medication will be ordered by their postpartum physician team through the inpatient pharmacy and dispensed by their inpatient nursing team, as per standard of care. The decision for 10 mg vs 20 mg of rivaroxaban is based on inclusion criteria and patient's physician team's recommendation for prophylactic (10 mg) vs. therapeutic (20 mg) dosing.

Primary Outcome Measures

Name	Time	Method
Concentration of rivaroxaban in breast milk	Postpartum week 6	Time/concentration profile of rivaroxaban in breast milk 3 hours following morning dose on day 2 and onward
Absolute infant dose of rivaroxaban	6 week postpartum	The absolute infant dose is calculated from average drug concentrations in breast milk multiplied by an estimated breast milk intake of 150 mL/kg/day.
Relative infant dose	6 weeks postpartum	The relative infant dose is the absolute infant dose expressed as a percentage of the weight adjusted maternal dose, based on an average maternal weight of 75 kg. It is expressed in mg/kg/day.

Trial Locations

Locations (1)

Thomas Jefferson University Hospital; 🇺🇸 Philadelphia, Pennsylvania, United States