Emergence of in vitro resistance to lenacapavir is similar across HIV-1 subtypes

Objective: To assess the potential in vitro emergence of resistance mutations to the capsid inhibitor lenacapavir (LEN) in clinical samples from subtype B versus non-B HIV-1 subtype. Design: Twenty-four clinical isolates with non-B or B HIV-1 subtype were assessed for their in vitro susceptibility to LEN and their potential to develop resistance to LEN in viral breakthrough experiments. Methods: The HIV-1 gag -protease DNA fragment from various HIV-1 isolates was cloned (pXXLAI vector), and viruses were generated by transfection. Viruses were tested for antiretroviral drug susceptibility, and subjected to selection with LEN in tissue culture for up to 46 days. The capsid and reverse transcriptase sequence from the selected viruses were analyzed to determine the presence of resistance mutations. Results: Samples with HIV-1 subtype A1, AE, AG, B, C, D, F1, G, and H were evaluated. Wild-type susceptibility to LEN (EC 50 21–115 pM) was observed across all subtypes tested. Resistance selections in non-B subtype led to the emergence of the same mutations with similar timeframe as in subtype B. The most prevalent capsid mutations selected across all subtypes were N74D (9 of 25 cultures), Q67H (4/25), and T107N (4/25), while M66I, K70R/S, and N74H were also observed. Conclusions: In vitro susceptibility to LEN was not affected by the subtype of the samples tested, and selected resistance mutations were not significantly different across HIV-1 subtypes. These data indicate that LEN is a pan-genotypic inhibitor of HIV-1 that can be effective in all geographical settings, regardless of HIV-1 subtypes.