An antiretroviral drug released from an experimental vaginal ring to protect women against HIV is absorbed in low concentrations into breastmilk, according to researchers from the NIH-funded Microbicide Trials Network. The team touted data today from a Phase I trial of the device at the 9th IAS Conference on HIV Sciences in Paris.
The dapivirine ring was studied for 14 days in women who were no longer nursing their babies, but were still lactating. Use of the drug-device combo was also linked to low levels of dapivirine in the women’s plasma.
The Phase I study was the first study of the drug-eluting ring in lactating women. Previous work has shown that the dapivirine ring was safe and protected women against HIV in a 4,500-person study in sub-Saharan Africa.
The monthly, drug-releasing ring was developed by a non-profit, the International Partnership for Microbicides. The flexible, plastic device can be inserted, removed and replaced by the user. The non-profit is reportedly looking to win regulatory approval for the dapivirine rings for women ages 18 to 45.
Traditionally, women who participated in studies of the investigational ring could not be pregnant or breastfeeding, because the effects of dapivirine on fetuses and infants are unknown. However, many women remain sexually active during pregnancy and breastfeeding and therefore are still at risk of acquiring HIV.
The team of researchers hope to demonstrate the ring’s safety in a population of pregnant and breastfeeding women using this study and other future trials.
“There is little doubt that safe and effective HIV prevention methods are needed for women during all times of their lives,” principal investigator Sharon Hillier said in prepared remarks. “With the dapivirine ring, conducting this study was an important first step. If the ring is approved, we’d want it to ultimately be made available to all women, including those who are breastfeeding.
“Understanding the safe use of drugs in pregnancy and breastfeeding is a high priority across women’s health. Eventually, we hope that we can assure women that using the dapivirine ring during breastfeeding — and pregnancy – is safe, with minimal exposure of the drug to their infants. However, understanding a product’s safety during pregnancy and breastfeeding requires carefully designed trials that can obtain critical safety information while also ensuring the well-being of this special population. In this first study of dapivirine and breast milk, we were able to gather initial data without exposing infants to drug,” MTN’s scientific director for pregnancy research, Lisa Noguchi, added.
The most recent study enrolled 16 women who were no longer breastfeeding but were still pumping breast milk. Researchers collected samples of milk and blood plasma prior to use of the ring, 3 hours, 6 hours, 24 hours, seven days and 14 days after insertion. After the ring was removed, the team collected samples two days later.
They detected dapivirine in all of the women’s milk and plasma, starting at 3 hours and increasing until leveling off between seven and 14 days. Just two days after the ring was removed, dapivirine levels were down 60%.
Next up, the team plans to evaluate attitudes relating to the use of a vaginal, antiretroviral ring during pregnancy and breastfeeding among pregnant women, male partners and healthcare leaders at sites in Malawi, Uganda, South Africa and Zimbabwe.
The researchers also want to assess the drug-eluting ring for safety in 750 pregnant women and 100 women who are breastfeeding.