Archived Comments for:
Baseline data of parasite clearance in patients with falciparum malaria treated with an artemisinin derivative: an individual patient data meta-analysis
Ian Hastings, Liverpool School of Tropical Medicine
24 November 2015
We would like to draw readers' attention to a very recent paper by us in which we used pharmacological modelling to investigate the properties of "parasite" (more accurately, infected red blood cell iRBC) clearance rates following antimalarial drug treatment [1]. Presumably this very recent publications was not available to the authors of the current study. Also, we were unaware of this paper which is unfortunate as its observations broadly support the conclusions of our paper. We do not object to the analyses or methodology described here, rather to the context in which they were discussed. Readers of our paper will realise that we would strongly disagree with several of the assertions made in the current paper such as its first sentence, i.e. "Parasite clearance is a robust measure of the efficacy of anti-malarial drugs…". In fact, we concluded that clearance rates are highly non-robust. They have poor specificity because host immunity is usually the dominant factor determining clearance rates (a point also made by other authors e.g. [2, 3]) which explains why the major influences of clearance rates reported in the paper were surrogates of immunity i.e. age and initial parasitaemia. Readers are, of course, welcome to make up their own minds about the likely properties of iRBC clearance rates post-treatment, hence this note pointing to our manuscript.
Ian Hastings, Katherine Kay, Eva Maria Hodel
Liverpool School of Tropical Medicine
1. Hastings IM, Kay K, Hodel EM: How robust are malaria parasite clearance rates as indicators of drug effectiveness and resistance? Antimicrob Agents Chemother 2015, 59:6428-6436.
2. Krishna S, Kremsner PG: Antidogmatic approaches to artemisinin resistance: reappraisal as treatment failure with artemisinin combination therapy. Trends in Parasitology 2013, 29:313-317.
3. Ferreira PE, Culleton R, Gil JP, Meshnick SR: Artemisinin resistance in Plasmodium falciparum: what is it really? Trends in Parasitology 2013, 29:318-320.
Note to MJ
24 November 2015
We would like to draw readers' attention to a very recent paper by us in which we used pharmacological modelling to investigate the properties of "parasite" (more accurately, infected red blood cell iRBC) clearance rates following antimalarial drug treatment [1]. Presumably this very recent publications was not available to the authors of the current study. Also, we were unaware of this paper which is unfortunate as its observations broadly support the conclusions of our paper. We do not object to the analyses or methodology described here, rather to the context in which they were discussed. Readers of our paper will realise that we would strongly disagree with several of the assertions made in the current paper such as its first sentence, i.e. "Parasite clearance is a robust measure of the efficacy of anti-malarial drugs…". In fact, we concluded that clearance rates are highly non-robust. They have poor specificity because host immunity is usually the dominant factor determining clearance rates (a point also made by other authors e.g. [2, 3]) which explains why the major influences of clearance rates reported in the paper were surrogates of immunity i.e. age and initial parasitaemia. Readers are, of course, welcome to make up their own minds about the likely properties of iRBC clearance rates post-treatment, hence this note pointing to our manuscript.
Ian Hastings, Katherine Kay, Eva Maria Hodel
Liverpool School of Tropical Medicine
1. Hastings IM, Kay K, Hodel EM: How robust are malaria parasite clearance rates as indicators of drug effectiveness and resistance? Antimicrob Agents Chemother 2015, 59:6428-6436.
2. Krishna S, Kremsner PG: Antidogmatic approaches to artemisinin resistance: reappraisal as treatment failure with artemisinin combination therapy. Trends in Parasitology 2013, 29:313-317.
3. Ferreira PE, Culleton R, Gil JP, Meshnick SR: Artemisinin resistance in Plasmodium falciparum: what is it really? Trends in Parasitology 2013, 29:318-320.
Competing interests
I declare no competing interests