Cross-resistance of the chloroquine-derivative AQ-13 with amodiaquine in Cambodian Plasmodium falciparum isolates

10 Jul 2021

Flore Nardella, Mélissa Mairet-Khedim, Camille Roesch, Steven P Maher, Sopheakvatey Ke, Rithea Leang, Didier Leroy, Benoit Witkowski

Journal of Antimicrobial Chemotherapy

Doi: 10.1093/jac/dkab219




Expanding resistance to multiple antimalarials, including chloroquine, in South-East Asia (SEA) urges the development of new therapies. AQ-13, a chloroquine derivative, is a new drug candidate for treating malaria caused by Plasmodium falciparum.


Possible cross-resistance between the 4-aminoquinolines amodiaquine, piperaquine and AQ-13 has not been assessed. In vitro parasite growth assays were used to characterize the susceptibility of multidrug-resistant and susceptible P. falciparum patient isolates to AQ-13.


A [3H]hypoxanthine uptake assay and a 384-well high content imaging assay were used to assess efficacy of AQ-13 and desethyl-amodiaquine against 38 P. falciparum isolates.


We observed a strong cross-resistance between the chloroquine derivative amodiaquine and AQ-13 in Cambodian P. falciparum isolates (Pearson correlation coefficient of 0.8621, P < 0.0001).


In light of the poor efficacy of amodiaquine that we described recently in Cambodia, and its cross resistance with AQ-13, there is a significant risk that similar clinical efficacy of AQ-13-based combinations should be anticipated in areas of amodiaquine resistance.

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