Pregnancy outcomes and pharmacokinetics in pregnant women living with HIV exposed to long-acting cabotegravir and rilpivirine in clinical trials

Background: Limited data exist on pregnant women living with HIV exposed to cabotegravir + rilpivirine (CAB + RPV). Outcomes in pregnant participants exposed to CAB + RPV, and pharmacokinetic washout data in those exposed to CAB + RPV long-acting (LA) with live births, are presented. Methods: Women exposed to one or more doses of CAB + RPV (oral/LA) from ViiV Healthcare-sponsored phase 2b/3/3b clinical trials and the compassionate use programme who became pregnant were included. Upon pregnancy in the trial programme, CAB + RPV was discontinued, an alternative antiretroviral regimen was initiated, and quarterly pharmacokinetic sampling for 52 weeks post-last injection was obtained. CAB + RPV continuation or alternative antiretroviral regimen initiation was decided by pregnant compassionate use programme participants and their treating physicians. Results: As of 31 March 2021, 25 pregnancies following CAB + RPV exposure at conception were reported (five oral, 20 LA), including four who conceived during pharmacokinetic washout following treatment discontinuation. There were eight elective abortions, six miscarriages (five in first trimester), one ectopic pregnancy, and 10 live births (one oral, nine LA), including one infant born with congenital ptosis. Among participants exposed to CAB + RPV LA at conception with live births, plasma CAB and RPV washout concentrations during pregnancy were within the range of those observed in non-pregnant women. Conclusion: In this first analysis of pregnancy outcomes following CAB + RPV exposure at conception, 10 live births, including one with congenital anomaly, were reported. Plasma CAB and RPV washout concentrations during pregnancy were within the range of those in non-pregnant women. Pregnancy surveillance within ViiV Healthcare-sponsored clinical trials is ongoing, with dedicated pregnancy studies planned.