Fostemsavir and ethinyl estradiol drug interaction: Clinical recommendations for co-administration.

Applying the results of Study 206279 and other relevant ARV-contraceptive studies, we recommend that when co-administering fostemsavir with combined oral contraceptives (COCs) and other oestrogen-based therapies, EE dose should not exceed 30 μg or equivalent, and caution is advised in the case of individuals with risk factors for thromboembolic events. Other oestrogen-based therapies may be co-administered with fostemsavir, with monitoring of oestrogen concentrations and appropriate dose adjustments. No impact of fostemsavir on COC efficacy is expected.