Model-Informed Evaluation of Hydroxyurea Exposure During Lactation

Area of Science:

• Pharmacokinetics
• Maternal-infant health
• Sickle cell disease management

Background:

• Hydroxyurea is essential for sickle cell anemia treatment.
• Limited data exists on hydroxyurea use during lactation.
• Assessing infant exposure is crucial for maternal therapy continuation.

Purpose of the Study:

• Develop a population pharmacokinetic (PK) model for hydroxyurea in maternal plasma and breast milk.
• Quantify infant exposure to hydroxyurea through breastfeeding.
• Evaluate safety thresholds for lactational hydroxyurea exposure.

Main Methods:

• Population PK modeling using nonlinear mixed-effects modeling (HELPS study).
• Estimation of maternal plasma and breast milk PK parameters.
• Model-based simulations to calculate relative infant dose (RID) across infant ages 0-9 months.

Main Results:

• The PK model accurately described hydroxyurea disposition in plasma and breast milk.
• Simulated relative infant doses (RID) remained below the 10% safety threshold for all infant age groups.
• The model provides a framework for assessing lactational drug exposure.

Conclusions:

• Infant exposure to hydroxyurea via breastfeeding is unlikely to exceed the 10% safety threshold.
• Continued maternal hydroxyurea therapy during lactation is supported with clinical oversight.
• This PK model aids in managing sickle cell anemia in lactating individuals.