REAP (Rapid Elimination of Active Plasmodium): A photodynamic strategy exploiting intrinsic kinetics of the parasite to combat severe malaria

Plasmodium falciparum, the causative organism of Malaria is a mosquito-borne parasitic disease which infects red blood cells (RBCs), where it multiplies rapidly and goes through different stages of its life cycle. When the parasite load exceeds >3% in the blood, malaria transforms into severe malaria which requires immediate attention as death occurs within hours to days. The increase in people traveling to malaria-endemic areas and resistance/partial resistance to most known antimalarial drugs has put the current management scheme in jeopardy. To improve the patient outcome at this point, the physician may opt to perform exchange transfusions from another individual as an adjunct therapy to reduce parasitized RBCs, but the strategy has many drawbacks, including chances of infection. These limitations can be mitigated if the patient's own blood is withdrawn/extracted, sterilized from the parasitic load and then re-transfused almost similar to what is done in extracorporeal blood treatment for sepsis, poisoning and graft versus host disease. Thus, in the present study a light-based photochemical approach, Photodynamic Therapy (PDT) built on delta-aminolevulinic acid-protoporphyrin IX (ALA-PpIX) synthesis is exploited. This modality was effective at destruction of both resistant and susceptible strains of parasites, including at a high load mimicking severe drug resistant malaria. The current findings have set the stage for concept of an ALA-PpIX based PDT platform, "the REAP (Rapid Elimination of Active Plasmodium) strategy". This approach provides an additional tool towards the defense against multi-drug resistant severe malaria, and other intracellular blood pathogens, dependent on heme-synthesis.

Red blood cell exchange in treatment of severe cerebral P. falciparum malaria: A case report

INTRODUCTION

Red blood cells exchange transfusion has been demonstrated to be helpful in treatment of sever P. falciparum malaria. However, no large scale randomized controlled trials have been completed to date and the CDC does not recommend RBC exchange transfusions as standard of care. We present a case of severe cerebral malaria in a patient with extremely high parasitemia and severe altered mental status who improved rapidly with automated RBC exchange.

REPORT

Seventy-two year old female presented with 1 day history of weakness, altered mental status, malaise, and cyclic sweats after returning from a trip to Sierra Leone. Thick and Thin Smears demonstrated P. falciparum rings present and Quantitative malaria screen demonstrated 53.33% parasitemia. Patient was started on quinidine and doxycycline but continued to deteriorate. Automated RBC exchange transfusion was performed within 24 hours of admission and resulted in rapid improvement in symptomology. Repeat thick and thin smears revealed undetectable parasite load.

CONCLUSION

Automated RBC exchange may improve outcomes in severe P. falciparum malaria when presenting parasite loads are very high.

Malaria: an update on current chemotherapy

INTRODUCTION

Chemotherapy of malaria has become a rapidly changing field. Less than two decades ago, treatment regimens were increasingly bound to fail due to emerging drug resistance against 4-aminoquinolines and sulfa compounds. By now, artemisinin-based combination therapies (ACTs) constitute the standard of care for uncomplicated falciparum malaria and are increasingly also taken into consideration for the treatment of non-falciparum malaria.

AREAS COVERED

This narrative review provides an overview of the state-of-art antimalarial drug therapy, highlights the global portfolio of current Phase III/IV clinical trials and summarizes current developments.

EXPERT OPINION

Malaria chemotherapy remains a dynamic field, with novel drugs and drug combinations continuing to emerge in order to outpace the development of large-scale drug resistance against the currently most important drug class, the artemisinin derivatives. More randomized controlled studies are urgently needed especially for the treatment of malaria in first trimester pregnant women. ACTs should be used for the treatment of imported malaria more consequently. Gaining sufficient efficacy and safety information on ACT use for non-falciparum species including Plasmodium ovale and malariae should be a research priority. Continuous investment into malaria drug development is a vital factor to combat artemisinin resistance and successfully improve malaria control toward the ultimate goal of elimination.