UCSF

Background

A monthly treatment course of dihydroartemisinin-piperaquine (DHA-PQ) effectively prevents malaria during pregnancy. However, a drug-drug interaction pharmacokinetic (PK) study found that pregnant human immunodeficiency virus (HIV)-infected women receiving efavirenz-based antiretroviral therapy (ART) had markedly reduced piperaquine (PQ) exposure. This suggests the need for alternative DHA-PQ chemoprevention regimens in this population.

Methods

Eighty-three HIV-infected pregnant women who received monthly DHA-PQ and efavirenz contributed longitudinal PK and corrected QT interval (QTc) (n = 25) data. Population PK and PK-QTc models for PQ were developed to consider the benefits (protective PQ coverage) and risks (QTc prolongation) of alternative DHA-PQ chemoprevention regimens. Protective PQ coverage was defined as maintaining a concentration >10 ng/mL for >95% of the chemoprevention period.

Results

PQ clearance was 4540 L/day. With monthly DHA-PQ (2880 mg PQ), <1% of women achieved defined protective PQ coverage. Weekly (960 mg PQ) or low-dose daily (320 or 160 mg PQ) regimens achieved protective PQ coverage for 34% and >96% of women, respectively. All regimens were safe, with ≤2% of women predicted to have ≥30 msec QTc increase.

Conclusions

For HIV-infected pregnant women receiving efavirenz, low daily DHA-PQ dosing was predicted to improve protection against parasitemia and reduce risk of toxicity compared to monthly dosing.

Clinical trials registration

NCT02282293.