Since we first added lenacapavir to the website, the nature of interactions with sensitive CYP3A4 substrates has become clearer. We have completed a review of the interactions between lenacapavir and such comedications to determine if any changes were required.
The revisions to the interaction summaries take into account product label recommendations for sensitive CYP3A4 substrates and the management of drug-drug interactions (DDIs) with moderate inhibitors based on DDI data/recommendation for other moderate inhibitors. In general drugs with modest DDIs and good safety profiles have been downgraded, although some drugs (even with modest DDIs) have remained as amber if they have a narrow therapeutic index or an important toxicity profile. In addition, the warning regarding effect of residual lenacapavir concentrations has been removed for comedications that are not sensitive CYP3A4 substrates and are not narrow therapeutic index drugs as residual concentrations are not problematic for such drugs.
In total, 111 interactions were identified as being with sensitive CYP3A4 substrates, with 67 (60.4%) being revised with no colour change, 43 (38.7%) being downgraded and only 1 (0.9%) being upgraded.
These changes are now on the website checker and an app update for the HIV iChart database will have been automatically generated. Updated PDFs for Treatment Selectors and Interaction Summary Charts have been uploaded to the Prescribing Resources section of the website.