Minutes of the Technical Expert Group (TEG) on Drug Efficacy and Response

Overview

There is sufficient evidence to confirm Pfplasmepsin 2-3 increased copy number as a marker of piperaquine resistance in Asia. Pfplasmepsin 2-3 increased copy number should be incorporated into surveillance and monitoring activities globally where piperaquine is being used or considered for use. Although other mutations/amplifications may be involved in piperaquine resistance, including novel Pfcrt mutations, these require further research and validation before recommendations can be made.

Based on the proportion of clinical treatment failures determined in a therapeutic efficacy study (TES), no threshold for the prevalence of Pfplasmepsin 2-3 increased copy number was recommended for treatment policy change. Nonetheless, the predictive value of Pfplasmepsin 2-3 increased copy number prevalence with respect to clinical failure could be useful in informing the threshold at which a TES should be conducted. Pfkelch 13 prevalence and a growing prevalence of Pfplasmepsin 2-3 increased copy number should be considered in situations where a TES might not be feasible.

Piperaquine survival assay should be the standard in vitro assessment for piperaquine phenotype. However, IC₉₀ obtained from conventional in vitro drug sensitivity assays also represents a valid method.