Takemi Program in International Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
Cambridge Institute of Therapeutic Immunology & Infectious Disease, Cambridge, UK.
J Antimicrob Chemother. 2024 Feb 1;79(2):339-348. doi: 10.1093/jac/dkad386.
Maintenance monotherapy with ritonavir-boosted darunavir has yielded variable outcomes and is not recommended. Trial samples offer valuable opportunities for detailed studies. We analysed samples from a 48 week trial in Cameroon to obtain a detailed characterization of drug resistance.
Following failure of NNRTI-based therapy and virological suppression on PI-based therapy, participants were randomized to ritonavir-boosted darunavir (n = 81) or tenofovir disoproxil fumarate/lamivudine +ritonavir-boosted lopinavir (n = 39). At study entry, PBMC-derived HIV-1 DNA underwent bulk Protease and Reverse Transcriptase (RT) sequencing. At virological rebound (confirmed or last available HIV-1 RNA ≥ 60 copies/mL), plasma HIV-1 RNA underwent ultradeep Protease and RT sequencing and bulk Gag-Protease sequencing. The site-directed mutant T375A (p2/p7) was characterized phenotypically using a single-cycle assay.
NRTI and NNRTI resistance-associated mutations (RAMs) were detected in 52/90 (57.8%) and 53/90 (58.9%) HIV-1 DNA samples, respectively. Prevalence in rebound HIV-1 RNA (ritonavir-boosted darunavir, n = 21; ritonavir-boosted lopinavir, n = 2) was 9/23 (39.1%) and 10/23 (43.5%), respectively, with most RAMs detected at frequencies ≥15%. The resistance patterns of paired HIV-1 DNA and RNA sequences were partially consistent. No darunavir RAMs were found. Among eight participants experiencing virological rebound on ritonavir-boosted darunavir (n = 12 samples), all had Gag mutations associated with PI exposure, including T375N, T375A (p2/p7), K436R (p7/p1) and substitutions in p17, p24, p2 and p6. T375A conferred 10-fold darunavir resistance and increased replication capacity.
The study highlights the high resistance barrier of ritonavir-boosted darunavir while identifying alternative pathways of resistance through Gag substitutions. During virological suppression, resistance patterns in HIV-1 DNA reflect treatment history, but due to technical and biological considerations, cautious interpretation is warranted.
利托那韦增强的达芦那韦单药维持治疗的结果存在差异，因此不被推荐。试验样本为详细研究提供了有价值的机会。我们分析了喀麦隆一项为期 48 周的试验中的样本，以获得耐药性的详细特征。
在基于 NNRTI 的治疗失败和基于 PI 的治疗病毒学抑制后，参与者被随机分配到利托那韦增强的达芦那韦（n = 81）或替诺福韦二吡呋酯/富马酸替诺福韦二吡呋酯+利托那韦增强的洛匹那韦（n = 39）组。在研究入组时，从 PBMC 中提取的 HIV-1 DNA 进行了大量蛋白酶和逆转录酶（RT）测序。在病毒学反弹（确认或最后一次可检测到的 HIV-1 RNA≥60 拷贝/ml）时，对血浆 HIV-1 RNA 进行了超深度蛋白酶和 RT 测序以及大量 gag 蛋白酶测序。使用单循环测定法对靶向突变 T375A（p2/p7）进行了表型特征分析。
在 52/90（57.8%）和 53/90（58.9%）HIV-1 DNA 样本中分别检测到 NRTI 和 NNRTI 耐药相关突变（RAMs）。在反弹的 HIV-1 RNA 中（利托那韦增强的达芦那韦，n = 21；利托那韦增强的洛匹那韦，n = 2）的流行率分别为 9/23（39.1%）和 10/23（43.5%），大多数 RAMs 的检出频率≥15%。配对 HIV-1 DNA 和 RNA 序列的耐药模式部分一致。未发现达芦那韦 RAMs。在 8 名接受利托那韦增强的达芦那韦治疗病毒学反弹的参与者中（n = 12 个样本），所有参与者均存在与 PI 暴露相关的 gag 突变，包括 T375N、T375A（p2/p7）、K436R（p7/p1）以及 p17、p24、p2 和 p6 中的取代。T375A 赋予达芦那韦 10 倍耐药性并增加复制能力。
该研究强调了利托那韦增强的达芦那韦具有较高的耐药屏障，同时通过 gag 取代确定了耐药的替代途径。在病毒学抑制期间，HIV-1 DNA 中的耐药模式反映了治疗史，但由于技术和生物学方面的考虑，需要谨慎解释。
