疟疾,尤其是恶性疟原虫感染,仍然是一个巨大的问题,其治疗和控制受到耐药性的严重挑战。需要新的抗疟药。为了描述正在开发的抗疟疾药物风险管道,我们评估了对19种靶向恶性疟原虫ABC转运蛋白I家族成员1(乙酰辅酶A合成酶)或可能受突变影响的化合物的离体药物敏感性,细胞色素b,二氢乳清酸脱氢酶,延伸因子2,赖氨酰tRNA合成酶,苯丙氨酰-tRNA合成酶,血浆蛋白酶X,前药活化和抗性酯酶,2015年至2022年在乌干达东部收集的998株新鲜恶性疟原虫临床分离株和V型H+ATPase。使用SYBRgreen通过72小时生长抑制(半最大抑制浓度[IC50])测定来评估药物敏感性。现场分离株对铅抗疟药物高度敏感,具有低到中纳摩尔中位数IC50,接近先前报告的实验室菌株的值,对于所有测试的化合物。然而,确定了敏感性降低的异常值。对于具有共享靶标的化合物,IC50结果之间呈正相关。我们对编码假定靶标的基因进行了测序,以表征序列多样性,搜索先前用体外药物压力选择的多态性,并确定基因型-表型关联。我们在靶基因中发现了许多多态性,通常在<10%的分离物中,但是没有一个是以前在体外用药物压力选择的,并且没有与体外药物敏感性显着降低相关。总的来说,乌干达恶性疟原虫分离株对正在开发的19种化合物高度敏感,作为下一代抗疟药物,与循环乌干达寄生虫中缺乏预先存在或新的抗性突变一致。重要性耐药性需要开发新的抗疟药物。重要的是评估正在开发的化合物对非洲现在引起疾病的寄生虫的活性,大多数疟疾病例发生的地方,并确定这些寄生虫的突变是否会限制新药物的功效。我们发现,非洲分离株通常对19种研究的铅抗疟药物高度敏感。对假定的药物靶标进行测序,确定了这些基因中的多个突变,但这些突变通常与抗疟活性降低无关.这些结果提供了信心,即目前正在开发的测试抗疟化合物的活性不会受到非洲疟疾寄生虫中预先存在的抗性介导突变的限制。
Malaria, especially Plasmodium falciparum infection, remains an enormous problem, and its treatment and control are seriously challenged by drug resistance. New antimalarial drugs are needed. To characterize the Medicines for Malaria Venture pipeline of antimalarials under development, we assessed the ex vivo drug susceptibilities to 19 compounds targeting or potentially impacted by mutations in P. falciparum ABC transporter I family member 1, acetyl-CoA synthetase, cytochrome b, dihydroorotate dehydrogenase, elongation factor 2, lysyl-tRNA synthetase, phenylalanyl-tRNA synthetase, plasmepsin X, prodrug activation and resistance esterase, and V-type H+ ATPase of 998 fresh P. falciparum clinical isolates collected in eastern Uganda from 2015 to 2022. Drug susceptibilities were assessed by 72-h growth inhibition (half-maximum inhibitory concentration [IC50]) assays using SYBR green. Field isolates were highly susceptible to lead antimalarials, with low- to midnanomolar median IC50s, near values previously reported for laboratory strains, for all tested compounds. However, outliers with decreased susceptibilities were identified. Positive correlations between IC50 results were seen for compounds with shared targets. We sequenced genes encoding presumed targets to characterize sequence diversity, search for polymorphisms previously selected with in vitro drug pressure, and determine genotype-phenotype associations. We identified many polymorphisms in target genes, generally in <10% of isolates, but none were those previously selected in vitro with drug pressure, and none were associated with significantly decreased ex vivo drug susceptibility. Overall, Ugandan P. falciparum isolates were highly susceptible to 19 compounds under development as next-generation antimalarials, consistent with a lack of preexisting or novel resistance-conferring mutations in circulating Ugandan parasites. IMPORTANCE Drug resistance necessitates the development of new antimalarial drugs. It is important to assess the activities of compounds under development against parasites now causing disease in Africa, where most malaria cases occur, and to determine if mutations in these parasites may limit the efficacies of new agents. We found that African isolates were generally highly susceptible to the 19 studied lead antimalarials. Sequencing of the presumed drug targets identified multiple mutations in these genes, but these mutations were generally not associated with decreased antimalarial activity. These results offer confidence that the activities of the tested antimalarial compounds now under development will not be limited by preexisting resistance-mediating mutations in African malaria parasites.