Optimal primaquine use for radical cure of Plasmodium vivax and Plasmodium ovale malaria in Japanese travelers--A retrospective analysis

Primaquine plus clindamycin as a promising salvage therapy for Pneumocystis jirovecii pneumonia: A retrospective analysis in Japanese patients

Treatment of intractable Pneumocystis jirovecii pneumonia (PCP) patients with primaquine (PQ) in combination with clindamycin (CLDM) was conducted by the Research Group on Chemotherapy of Tropical Diseases (RG-CTD), as a kind of compassionate use. Primaquine was not nationally licensed at the time but imported by RG-CTD for the use in a clinical research to investigate safety and efficacy in malaria treatment. Eighteen Japanese adult patients thus treated were analyzed. Prior to the treatment with PQ-CLDM, most of the patients had been treated with trimethoprim-sulfamethoxazole first, all of which being followed by pentamidine and/or atovaquone treatment. This combination regimen of PQ-CLDM was effective in 16 (89%) patients and developed adverse events (AEs) in five (28%) patients. AEs included skin lesions, methemoglobinemia, and hepatic dysfunction, though none of them were serious. As a second-line or salvage treatment for PCP, PQ-CLDM appears to be a better option than pentamidine or atovaquone. Currently in Japan, both PQ and CLDM are licensed drugs but neither of them is approved for treatment of PCP. Considering the potentially fatal nature of PCP, approval of PQ-CLDM for treating this illness should be urged.

Imported Malaria at a Referral Hospital in Tokyo from 2005 to 2016: Clinical Experience and Challenges in a Non-Endemic Setting

In this study, we reviewed imported malaria cases observed at the National Center for Global Health and Medicine, Tokyo, between 2005 and 2016, to comprehend their demographic and clinical characteristics. Data on 169 cases were used to analyze demographic information; data on 146 cases were used for the analysis of clinical information. The median patients’ age was 34 years, and 79.3% of them were male. The proportion of non-Japanese patients increased and surpassed that of Japanese patients after 2015. In 82.2% of the cases, the region of acquisition was Africa, and Plasmodium falciparum was the dominant species (74.0%) followed by Plasmodium vivax (15.4%). We observed 19 (18.4%, 19/103) severe falciparum malaria cases. Mefloquine was the most commonly used drug for treatment until the early 2010s; atovaquone/proguanil was the most commonly used after its licensure in 2013. Although none of the patients died, four recrudescence episodes after artemether/lumefantrine (A/L) treatment and one relapse episode were observed. Overall, malaria was diagnosed on median day 4 of illness, and, thereon, treatment was initiated without delay. Diagnosis on day 5 or later was significantly associated with severe disease in Japanese cases (odds ratio = 4.1; 95% CI = 1.2–14.3). We observed a dominance of falciparum malaria, an increase in the number of non-Japanese cases, late treatment failure after A/L treatment, a low relapse rate, and an association between delayed malaria diagnosis and higher disease severity. Pretravel care and early diagnosis are necessary to reduce malaria-related mortality and morbidity in settings such as ours.

Guidance for Using Tafenoquine for Prevention and Antirelapse Therapy for Malaria - United States, 2019

An estimated 219 million cases of malaria occurred worldwide in 2017, causing approximately 435,000 deaths (1). Malaria is caused by intraerythrocytic protozoa of the genus Plasmodium transmitted to humans through the bite of an infective Anopheles mosquito. Five Plasmodium species that regularly cause illness in humans are P. falciparum, P. vivax, P. ovale, P. malariae, and P. knowlesi (2). The parasite first develops in the liver before infecting red blood cells. Travelers to areas with endemic malaria can prevent malaria by taking chemoprophylaxis. However, most antimalarials do not kill the liver stages of the parasite, including hypnozoites that cause relapses of disease caused by P. vivax or P. ovale. Therefore, patients with these relapsing species must be treated with two medications: one for the acute infection, and another to treat the hypnozoites (antirelapse therapy). Until recently, primaquine was the only drug available worldwide to kill hypnozoites. Tafenoquine, a long-acting 8-aminoquinoline drug related to primaquine, was approved by the Food and Drug Administration (FDA) on July 20, 2018, for antirelapse therapy (Krintafel) and August 8, 2018, for chemoprophylaxis (Arakoda) (3,4). This report reviews evidence for the efficacy and safety of tafenoquine and provides CDC guidance for clinicians who prescribe chemoprophylaxis for travelers to areas with endemic malaria and treat malaria.

Retrospective observational study of the use of artemether-lumefantrine in the treatment of malaria in Japan

BACKGROUND

The Research Group on Chemotherapy of Tropical Diseases, Japan, introduced artemether-lumefantrine (AL) in late 2002, mainly for treating uncomplicated Plasmodium falciparum malaria. Because AL was on the market in Japan in March 2017, the effectiveness and safety of AL were analyzed to help medical personnel use AL optimally.

METHODS

Case report forms submitted by the attending physicians were analyzed. When necessary, direct contact with the attending physicians was made to obtain detailed information.

RESULTS

Effectiveness analysis was performed for 62 cases and safety analysis was performed for 66 cases. In P. falciparum malaria, the overall cure rate was 91.1% (51/56), of which the cure rates for Japanese and non-Japanese patients were 82.1% (23/28) and 100% (28/28), respectively. The successfully treated cases included severe P. falciparum malaria, with parasite densities exceeding 500,000/μL. Adverse events were reported in 14 patients, including delayed hemolytic anemia which occurred in the top four highest parasitemic cases.

CONCLUSIONS

AL treatment failure in P. falciparum malaria may not be rare among non-immune individuals, including Japanese. The possibility of delayed hemolytic anemia, which occurs preferentially in high parasitemic cases, should be considered following AL treatment.

Severe delayed haemolytic anaemia associated with artemether-lumefantrine treatment of malaria in a Japanese traveller

Delayed haemolytic anaemia has been reported in association with intravenous artesunate treatment in patients with severe Plasmodium falciparum malaria, and furthermore, oral artemisinin-based combination therapies including artemether-lumefantrine (AL) have also been incriminated. However, definite cases of delayed haemolytic anaemia associated with AL appear to be scarce, as reported cases were often treated concomitantly with other anti-malarials. In this study, we report a severe case of delayed haemolytic anaemia following AL alone in a Japanese traveller with severe parasitaemia caused by numerous P. falciparum parasites and a few P. vivax parasites. We also stress the need by further studies to differentiate between delayed haemolytic anaemia and blackwater fever, the latter being another malaria-related haemolytic condition, more clearly than they are now.

Imported malaria in pregnant women experienced in Japan

INTRODUCTION

With ever-growing global exchanges, the number of travelers, including pregnant women, to the tropics is increasing, which poses a risk of contracting malaria. Although there are several reports on imported malaria in pregnancy from Western countries, those focusing on cases experienced in Japan are very limited.

METHODS

We searched for cases of malaria in pregnancy in the treatment records submitted to the Research Group on Chemotherapy of Tropical Diseases, Japan, during the period 1993-2016. Literature searches were also conducted using an American and a Japanese search system.

RESULTS

Ten cases of malaria in pregnant women were identified, including four cases with Plasmodium falciparum. Of eight evaluable cases, only one practiced malaria chemoprophylaxis. Among the nine evaluable cases, eight resulted in uneventful delivery and one P. falciparum case developed severe hepatic disturbance, disseminated intravascular coagulation, and intrauterine fetal death. After the initial attack, none of the Plasmodium vivax/Plasmodium ovale cases practiced chloroquine prophylaxis until delivery. One P. ovale case received a lower dose regimen of chloroquine as acute-stage therapy.

CONCLUSION

This study demonstrated additional cases of imported malaria in pregnant women to the literature and highlighted various epidemiological, demographic, and clinical characteristics. Some of the clinical issues raised need to be investigated. Due to the paucity of the cases worldwide, sharing information among various countries is indispensable, and international guidelines which are now increasingly recommending the use of artemisinins in pregnant women should be referred.

Prevention of Malaria Resurgence in Greece through the Association of Mass Drug Administration (MDA) to Immigrants from Malaria-Endemic Regions and Standard Control Measures

Greece was declared malaria-free in 1974 after a long antimalarial fight. In 2011–2012, an outbreak of P. vivax malaria was reported in Evrotas, an agricultural area in Southern Greece, where a large number of immigrants from endemic countries live and work. A total of 46 locally acquired and 38 imported malaria cases were detected. Despite a significant decrease of the number of malaria cases in 2012, a mass drug administration (MDA) program was considered as an additional measure to prevent reestablishment of the disease in the area. During 2013 and 2014, a combination of 3-day chloroquine and 14-day primaquine treatment was administered under direct observation to immigrants living in the epicenter of the 2011 outbreak in Evrotas. Adverse events were managed and recorded on a daily basis. The control measures implemented since 2011 continued during the period of 2013–2014 as a part of a national integrated malaria control program that included active case detection (ACD), vector control measures and community education. The MDA program was started prior to the transmission periods (from May to December). One thousand ninety four (1094) immigrants successfully completed the treatment, corresponding to 87.3% coverage of the target population. A total of 688 adverse events were recorded in 397 (36.2%, 95% C.I.: 33.4–39.1) persons, the vast majority minor, predominantly dizziness and headache for chloroquine (284 events) and abdominal pain (85 events) for primaquine. A single case of primaquine-induced hemolysis was recorded in a person whose initial G6PD test proved incorrect. No malaria cases were recorded in Evrotas, Laconia, in 2013 and 2014, though three locally acquired malaria cases were recorded in other regions of Greece in 2013. Preventive antimalarial MDA to a high-risk population in a low transmission setting appears to have synergized with the usual antimalarial activities to achieve malaria elimination. This study suggests that judicious use of MDA can be a useful addition to the antimalarial armamentarium in areas threatened with the reintroduction of the disease.

Greece was declared malaria-free in the year 1974 after a long antimalarial fight. In 2011–2012, a number of malaria cases reported in Evrotas, Laconia, in Southern Greece, where a large number of immigrants from malaria-endemic countries live and work. A total of 84 malaria cases, both in immigrants (38 cases) and in Greeks (46 cases), were detected. A number of malaria control measures were deployed in the area since 2011. Despite a decrease of the number of malaria cases in 2012, elimination could not be achieved, and thus antimalarial MDA was considered as an additional measure to prevent the reestablishment of the disease. During 2013 and 2014, a combination of two drugs was administered under direct observation to all immigrants in the epicenter of the 2011 Evrotas outbreak. The antimalarial MDA program was started on July-August and was successfully completed by 1094 immigrants (87.3% coverage). No serious adverse events were recorded except one case of primaquine-induced hemolysis due to false G6PD test result. In 2013 and 2014, no malaria cases were recorded in Evrotas, Laconia. This study suggests that careful use of supervised antimalarial MDA is a useful addition to the antimalarial control measures in areas threatened with the reintroduction of the disease.