Controlled trial of 3-day quinine-clindamycin treatment versus 7-day quinine treatment for adult travelers with uncomplicated falciparum malaria imported from the tropics

Phytochemical screening, antioxidant analyses, and in vitro and in vivo antimalarial activities of herbal medicinal plant - Rotheca serrata (L.) Steane & Mabb

ETHNOPHARMACOLOGICAL RELEVANCE

Malaria is a major global health concern that is presently challenged by the emergence of Plasmodium falciparum (Pf) resistance to mainstay artemisinin-based combination therapies (ACTs). Hence, the discovery of novel and effective antimalarial drugs is pivotal to treating and controlling malaria. For many years, traditional plant-based herbal medicines have been employed in the treatment of various illnesses. Rotheca serrata (L.) Steane & Mabb. belongs to the Lamiaceae family that has been traditionally used to treat, cure, and prevent numerous diseases including malaria.

AIM

The present investigation sought to assess the phytoconstituents, antioxidant, cytotoxicity, antimalarial activities of Rotheca serrata extract and its fractions. The in vitro antiplasmodial activity was assessed in chloroquine-sensitive Pf3D7 and artemisinin-resistant PfCam3.IR539T cultures, and the in vivo antimalarial activity was analyzed in Plasmodium berghei (Pb) ANKA strain-infected BALB/c mouse model.

MATERIALS AND METHODS

The fresh leaves of Rotheca serrata were extracted in methanol (RsMeOH crude leaf extract). A portion of the extract was used to prepare successive solvent fractions using ethyl acetate (RsEA) and hexane (RsHex). The in vitro antiplasmodial activity was evaluated using [3H]-hypoxanthine incorporation assays against Pf3D7 and PfCam3.IR539T cultures. In vitro cytotoxicity study on HeLa, HEK-293T, and MCF-7 cell lines was carried out using MTT assay. The human red blood cells (RBCs) were used to perform the hemolysis assays. In vitro antioxidant studies and detailed phytochemical analysis were performed using GC-MS and FTIR. The four-day Rane's test was performed to evaluate the in vivo antimalarial activity against Pb ANKA strain-infected mice.

RESULTS

Phytochemical quantification of Rotheca serrata extract (RsMeOH) and its fractions (RsEA and RsHex) revealed that RsMeOH crude extract and RsEA fraction had higher contents of total phenol and flavonoid than RsHex fraction. The RsEA fraction showed potent in vitro antiplasmodial activity against Pf3D7 and PfCam3.IR539T with IC50 values of 9.24 ± 0.52 μg/mL and 17.41 ± 0.43 μg/mL, respectively. The RsMeOH crude extract exhibited moderate antiplasmodial activity while the RsHex fraction showed the least antiplasmodial activity. The GC-MS and FTIR analysis of RsMeOH and RsEA revealed the presence of triterpenes, phenols, and hydrocarbons as major constituents. The RsMeOH crude extract was non-hemolytic and non-cytotoxic to HeLa, HEK-293T, and MCF-7 cell lines. The in vivo studies showed that a 1200 mg/kg dose of RsMeOH crude extract could significantly suppress parasitemia by ∼63% and prolong the survival of treated mice by ∼10 days. The in vivo antiplasmodial activity of RsMeOH was better than the RsEA fraction.

CONCLUSION

The findings of this study demonstrated that traditionally used herbal medicinal plants like R. serrata provide a platform for the identification and isolation of potent bioactive phytochemicals that in turn can promote the antimalarial drug research. RsMeOH crude extract and RsEA fraction showed antiplasmodial, antimalarial and antioxidant activities. Chemical fingerprinting analysis suggested the presence of bioactive phytocompounds that are known for their antimalarial effects. Further detailed investigations on RsMeOH crude extract and RsEA fraction would be needed for the identification of the entire repertoire of the active antimalarial components with potent pharmaceutical and therapeutic values.

Macrolides and associated antibiotics based on similar mechanism of action like lincosamides in malaria

Malaria, a parasite vector-borne disease, is one of the biggest health threats in tropical regions, despite the availability of malaria chemoprophylaxis. The emergence and rapid extension of Plasmodium falciparum resistance to various anti-malarial drugs has gradually limited the potential malaria therapeutics available to clinicians. In this context, macrolides and associated antibiotics based on similar mechanism of action like lincosamides constitute an interesting alternative in the treatment of malaria. These molecules, whose action spectrum is similar to that of tetracyclines, are typically administered to children and pregnant women. Recent studies have examined the effects of azithromycin and the lincosamide clindamycin, on isolates from different continents. Azithromycin and clindamycin are effective and well tolerated in the treatment of uncomplicated malaria in combination with quinine. This literature review assesses the roles of macrolides and lincosamides in the prophylaxis and treatment of malaria.

Atovaquone-proguanil in the treatment of imported uncomplicated Plasmodium falciparum malaria: a prospective observational study of 553 cases

Background

Each year, thousands of cases of uncomplicated malaria are imported into Europe by travellers. Atovaquone-proguanil (AP) has been one of the first-line regimens used in France for uncomplicated malaria for almost ten years. While AP’s efficacy and tolerance were evaluated in several trials, its use in “real life” conditions has never been described. This study aimed to describe outcome and tolerance after AP treatment in a large cohort of travellers returning from endemic areas.

Methods

Between September 2002 and January 2007, uncomplicated malaria treated in nine French travel clinics with AP were followed for 30 days after AP initiation. Clinical and biological data were collected at admission and during the follow-up.

Results

A total of 553 patients were included. Eighty-eight percent of them were born in Africa, and 61.8% were infected in West Africa, whereas 0.5% were infected in Asia. Migrants visiting friends and relatives (VFR) constituted 77.9% of the patients, the remainder (32.1%) were backpackers. Three-hundred and sixty-four patients (66%) fulfilled follow-up at day 7 and 265 (48%) completed the study at day 30. Three patients had treatment failure. One-hundred and seventy-seven adverse drug reactions (ADR) were reported during the follow-up; 115 (77%) of them were digestive ADR. Backpackers were more likely to experiment digestive ADR compared to VFR (OR = 3.8; CI 95% [1.8-8.2]). Twenty patients had to be switched to another regimen due to ADR.

Conclusion

This study seems to be the largest in terms of number of imported uncomplicated malaria cases treated by AP. The high rate of reported digestive ADR is striking and should be taken into account in the follow-up of patients since it could affect their adherence to the treatment. Beside AP, artemisinin combination therapy (ACT) is now recommended as first-line regimen. A comparison of AP and ACT, in terms of efficacy and tolerance, would be useful.

Therapy of uncomplicated falciparum malaria in Europe: MALTHER - a prospective observational multicentre study

BACKGROUND

Malaria continues to be amongst the most frequent infectious diseases imported to Europe. Whilst European treatment guidelines are based on data from studies carried out in endemic areas, there is a paucity of original prospective treatment data. The objective was to summarize data on treatments to harmonize and optimize treatment for uncomplicated malaria in Europe.

METHODS

A prospective observational multicentre study was conducted, assessing tolerance and efficacy of treatment regimens for imported uncomplicated falciparum malaria in adults amongst European centres of tropical and travel medicine.

RESULTS

Between December 2003 and 2009, 504 patients were included in 16 centres from five European countries. Eighteen treatment regimens were reported, the top three being atovaquone-proguanil, mefloquine, and artemether-lumefantrine. Treatments significantly differed with respect to the occurrence of treatment changes (p = 0.005) and adverse events (p = 0.001), parasite and fever clearance times (p < 0.001), and hospitalization rates (p = 0.0066) and durations (p = 0.001). Four recrudescences and two progressions to severe disease were observed. Compared to other regimens, quinine alone was associated with more frequent switches to second line treatment, more adverse events and longer inpatient stays. Parasite and fever clearance times were shortest with artemether-mefloquine combination treatment. Vomiting was the most frequent cause of treatment change, occurring in 5.5% of all patients but 9% of the atovaquone-proguanil group.

CONCLUSIONS

This study highlights the heterogeneity of standards of care within Europe. A consensus discussion at European level is desirable to foster a standardized management of imported falciparum malaria.

Clindamycin plus quinine for treating uncomplicated falciparum malaria: a systematic review and meta-analysis

Background

Artemisinin-based combinations are recommended for treatment of uncomplicated falciparum malaria, but are costly and in limited supply. Clindamycin plus quinine is an alternative non-artemisinin-based combination recommended by World Health Organization. The efficacy and safety of clindamycin plus quinine is not known. This systematic review aims to assess the efficacy of clindamycin plus quinine versus other anti-malarial drugs in the treatment of uncomplicated falciparum malaria.

Methods

All randomized controlled trials comparing clindamycin plus quinine with other anti-malarial drugs in treating uncomplicated malaria were included in this systematic review. Databases searched included: Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE and LILACS. Two authors independently assessed study eligibility, extracted data and assessed methodological quality. The primary outcome measure was treatment failure by day 28. Dichotomous data was compared using risk ratio (RR), in a fixed effects model.

Results

Seven trials with 929 participants were included. Clindamycin plus quinine significantly reduced the risk of day 28 treatment failure compared with quinine (RR 0.14 [95% CI 0.07 to 0.29]), quinine plus sulphadoxine-pyrimethamine (RR 0.17 [95% CI 0.06 to 0.44]), amodiaquine (RR 0.11 [95% CI 0.04 to 0.27]), or chloroquine (RR 0.11 [95% CI 0.04 to 0.29]), but had similar efficacy compared with quinine plus tetracycline (RR 0.33 [95% CI 0.01 to 8.04]), quinine plus doxycycline (RR 1.00 [95% CI 0.21 to 4.66]), artesunate plus clindamycin (RR 0.57 [95% CI 0.26 to 1.24]), or chloroquine plus clindamycin (RR 0.38 [95% CI 0.13 to 1.10]). Adverse events were similar across treatment groups but were poorly reported.

Conclusion

The evidence on the efficacy of clindamycin plus quinine as an alternative treatment for uncomplicated malaria is inconclusive. Adequately powered trials are urgently required to compare this combination with artemisinin-based combinations.

Diagnosis and therapy for hospitalized imported malaria in adults in Italy

BACKGROUND

The diagnosis and treatment of malaria in non-endemic countries presents a continuing challenge.

METHODS

Medical records were reviewed for 291 patients hospitalized with microscopically confirmed malaria diagnosed consecutively in two infectious diseases wards in Milano, Italy, between 1998 and 2007.

RESULTS

One hundred eighty-six (64%) were male; median age was 35 y (range 16-72 y). Of the 291 patients, 204 (70.1%) were non-immune travelers and 87 (29.9%) were considered semi-immune. In 228 patients (78.3%), Plasmodium falciparum was identified as the only causative malarial parasite. In 48 (16.5%), 9 (3.1%), and 1 (0.3%) cases, Plasmodium vivax, Plasmodium ovale, and Plasmodium malariae were diagnosed, respectively. Five mixed infections were observed (1.7%). Of the 233 falciparum cases (including mixed infections), 222 (95.3%) were acquired in sub-Saharan Africa. Fifty-four percent of P vivax infection were acquired in the Indian subcontinent and Southeast Asia. Chemoprophylaxis was used by 23.6% (61/258) subjects with only 32 fully compliant with the recommended regimen. At admission, fever, chills, and headache were present in 95.5, 59.5, and 55.3% of cases, respectively. Elevated serum lactate dehydrogenase levels (95%) and thrombocytopenia (82%) were the most frequently detected laboratory abnormalities. Thirty-five patients (15%) with P falciparum malaria presented with severe malaria according to the WHO criteria; in 19 patients (54.3%) more than one criteria was present. All patients recovered uneventfully. Inappropriate anti-malarial treatment occurred in 25 patients (8.6%) and were recorded more frequently among patients with a diagnosis of P vivax malaria (29.1%) as opposed to those affected by P falciparum (3.9%).

CONCLUSIONS

In our study more than two thirds of imported malaria cases were due to P falciparum with an excess of cases diagnosed in immigrants starting from the year 2000. Despite many available guidelines inappropriate initial malaria treatment is relatively frequent even when patients are managed in an infectious diseases ward.

Quinine, an old anti-malarial drug in a modern world: role in the treatment of malaria

Quinine remains an important anti-malarial drug almost 400 years after its effectiveness was first documented. However, its continued use is challenged by its poor tolerability, poor compliance with complex dosing regimens, and the availability of more efficacious anti-malarial drugs. This article reviews the historical role of quinine, considers its current usage and provides insight into its appropriate future use in the treatment of malaria. In light of recent research findings intravenous artesunate should be the first-line drug for severe malaria, with quinine as an alternative. The role of rectal quinine as pre-referral treatment for severe malaria has not been fully explored, but it remains a promising intervention. In pregnancy, quinine continues to play a critical role in the management of malaria, especially in the first trimester, and it will remain a mainstay of treatment until safer alternatives become available. For uncomplicated malaria, artemisinin-based combination therapy (ACT) offers a better option than quinine though the difficulty of maintaining a steady supply of ACT in resource-limited settings renders the rapid withdrawal of quinine for uncomplicated malaria cases risky. The best approach would be to identify solutions to ACT stock-outs, maintain quinine in case of ACT stock-outs, and evaluate strategies for improving quinine treatment outcomes by combining it with antibiotics. In HIV and TB infected populations, concerns about potential interactions between quinine and antiretroviral and anti-tuberculosis drugs exist, and these will need further research and pharmacovigilance.

Limited ability of Plasmodium falciparum pfcrt, pfmdr1, and pfnhe1 polymorphisms to predict quinine in vitro sensitivity or clinical effectiveness in Uganda

Quinine is a standard drug for treating severe malaria in Africa, and it is also increasingly used to treat uncomplicated disease. However, failures of quinine therapy are common, and it is unknown if failures in Africa are due to drug resistance. Recent studies have identified associations between in vitro quinine sensitivity and polymorphisms in genes encoding putative transporters, including well-described polymorphisms in pfcrt and pfmdr1 and varied numbers of DNNND or DDNHNDNHNND repeats in microsatellite 4760 (ms4760) of the predicted sodium-hydrogen exchanger, pfnhe1. To better characterize mediators of quinine response, we assessed associations between genetic polymorphisms, in vitro quinine sensitivity, and quinine treatment responses in Kampala, Uganda. Among 172 fresh clinical isolates tested in vitro, decreasing sensitivity to quinine was associated with accumulation of pfmdr1 mutations at codons 86, 184, and 1246. Nearly all parasites had pfcrt 76T, preventing analysis of associations with this mutation. pfnhe1 ms4760 was highly polymorphic. Parasites with 2 copies of either ms4760 repeat showed modest decreases in quinine sensitivity compared to those with 1 or ≥3 repeats, but the differences were not statistically significant. None of the above polymorphisms predicted treatment failure among 66 subjects treated with quinine for uncomplicated malaria. Our data suggest that quinine sensitivity is a complex trait and that known polymorphisms in pfcrt, pfmdr1, and pfnhe1, while associated with quinine sensitivity, are not robust markers for quinine resistance.

In vitro activities of quinine and other antimalarials and pfnhe polymorphisms in Plasmodium isolates from Kenya

Resistance to the amino alcohol quinine has been associated with polymorphisms in pfnhe, a sodium hydrogen exchanger. We investigated the role of this gene in quinine resistance in vitro in isolates from Kenya. We analyzed pfnhe whole-gene polymorphisms, using capillary sequencing, and pfcrt at codon 76 (pfcrt-76) and pfmdr1 at codon 86 (pfmdr1-86), using PCR-enzyme restriction methodology, in 29 isolates from Kilifi, Kenya, for association with the in vitro activities of quinine and 2 amino alcohols, mefloquine and halofantrine. In vitro activity was assessed as the drug concentration that inhibits 50% of parasite growth (IC50). The median IC50s of quinine, halofantrine, and mefloquine were 92, 22, and 18 nM, respectively. The presence of 2 DNNND repeats in microsatellite ms4760 of pfnhe was associated with reduced susceptibility to quinine (60 versus 227 nM for 1 and 2 repeats, respectively; P<0.05), while 3 repeats were associated with restoration of susceptibility. The decrease in susceptibility conferred by the 2 DNNND repeats was more pronounced in parasites harboring the pfmdr1-86 mutation. No association was found between susceptibility to quinine and the pfcrt-76 mutation or between susceptibility to mefloquine or halofantrine and the pfnhe gene and the pfcrt-76 and pfmdr1-86 mutations. Using previously published data on the in vitro activities of chloroquine, lumefantrine, piperaquine, and dihydroartemisinin, we investigated the association of their activities with pfnhe polymorphism. With the exception of a modulation of the activity of lumefantrine by a mutation at position 1437, pfnhe did not modulate their activities. Two DNNND repeats combined with the pfmdr1-86 mutation could be used as an indicator of reduced susceptibility to quinine.

Effectiveness of quinine versus artemether-lumefantrine for treating uncomplicated falciparum malaria in Ugandan children: randomised trial

OBJECTIVE

To compare the effectiveness of oral quinine with that of artemether-lumefantrine in treating uncomplicated malaria in children.

DESIGN

Randomised, open label effectiveness study.

SETTING

Outpatient clinic of Uganda's national referral hospital in Kampala.

PARTICIPANTS

175 children aged 6 to 59 months with uncomplicated malaria.

INTERVENTIONS

Participants were randomised to receive oral quinine or artemether-lumefantrine administered by care givers at home.

MAIN OUTCOME MEASURES

Primary outcomes were parasitological cure rates after 28 days of follow-up unadjusted and adjusted by genotyping to distinguish recrudescence from new infections. Secondary outcomes were adherence to study drug, presence of gametocytes, recovery of haemoglobin concentration from baseline at day 28, and safety profiles.

RESULTS

Using survival analysis the cure rate unadjusted by genotyping was 96% for the artemether-lumefantrine group compared with 64% for the quinine group (hazard ratio 10.7, 95% confidence interval 3.3 to 35.5, P=0.001). In the quinine group 69% (18/26) of parasitological failures were due to recrudescence compared with none in the artemether-lumefantrine group. The mean adherence to artemether-lumefantrine was 94.5% compared with 85.4% to quinine (P=0.0008). Having adherence levels of 80% or more was associated with a decreased risk of treatment failure (0.44, 0.19 to 1.02, P=0.06). Adverse events did not differ between the two groups.

CONCLUSIONS

The effectiveness of a seven day course of quinine for the treatment of uncomplicated malaria in Ugandan children was significantly lower than that of artemether-lumefantrine. These findings question the advisability of the recommendation for quinine therapy for uncomplicated malaria in Africa.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00540202.

Possible autochthonous malaria from Marseille to Minneapolis

We report 2 cases of Plasmodium falciparum malaria in southern France in a French woman and an American man of Togolese origin who reported no recent travel to malaria-endemic countries. Both infections occurred after a stay near Marseille, which raises the possibility of autochthonous transmission. Entomologic and genotypic investigations are described.

Mefloquine versus 3-day oral quinine–clindamycin in uncomplicated imported falciparum malaria

In this open randomized trial comparing 3-day oral quinine-clindamycin versus standard mefloquine regimen for uncomplicated imported falciparum malaria, mefloquine treatment was associated with a higher risk of discontinuation of the treatment (RR=1.8, 95% CI [1.1-2.8]) related to mainly mild gastrointestinal adverse drug events. The poor tolerability of mefloquine sets a question mark against its use in outpatients.

[Imported malaria at the Marseilles Hôpital-Nord, France: a prospective study on 352 cases between 2001 and 2003]

OBJECTIVE

The authors had for aim to study epidemiological, clinical, and parasitological characteristics, as well as regimen received, of imported malaria cases hospitalised at the North University Hospital, in Marseilles, France.

DESIGN

The patients presenting with imported malaria included in this study were hospitalised in the infectious and tropical diseases unit and in the pediatrics unit at the North University Hospital, from January 1, 2001 to December 31, 2003. Variables were prospectively collected and recorded.

RESULTS

352 patients including 240 adults and 112 children were included. Most of them (67% of the adults and 92% of the children) were contaminated during a trip to the Comoros Islands. Plasmodium falciparum was the most common species identified. 97.5% of adult and 98% of child patients back from Comoros did not take any chemoprophylaxis against malaria or took inadequate regimens. Halofantrin was the most commonly used drug for children to treat uncomplicated P. falciparum malaria. In adults, atovaquone-proguanil was used as a first line drug in the absence of vomiting, and a 3-day intravenous regimen of quinine-clindamycin in case of vomiting.

CONCLUSION

The specificity of imported malaria in Marseilles is the high proportion of Comorian patients who go back home periodically to visit friends and relatives. A better education of the Comorian population in Marseilles, regarding malaria risks and prophylaxis, needs to be implemented.

Mefloquine versus quinine plus sulphalene-pyrimethamine (metakelfin) for treatment of uncomplicated imported falciparum malaria acquired in Africa

We conducted a multicenter, randomized, open-label trial to compare mefloquine with a 3-day quinine plus sulphalene-pyrimethamine (SP) regimen for the treatment of imported uncomplicated malaria acquired in Africa. The end points of the study were efficacy, tolerability, and length of hospital stay. From July 1999 to February 2003, 187 patients were enrolled in five centers in Italy, of whom 93 were randomized to receive mefloquine (the M group) and 94 were randomized to receive quinine plus SP (the QSP group). Immigrants and visiting relatives and friends represented 90% of the cases and were mainly from western African countries. A slightly increased proportion of cases in the QSP group had abnormal alanine aminotransferase levels at the baseline. The early cure rate was similar in the two groups: 98.9% (confidence interval [CI] = 97 to 100%) in the M group and 96.8% (CI = 93 to 100%) in the QSP group. The extended follow-up was completed by 135 subjects (72.2%), and no case of recrudescence was detected. There were no differences in the parasite clearance time, but patients in the M group had shorter mean fever clearance time (35.9 h versus 44.4 h for the QSP group; P = 0.05) and a shorter mean hospital stay (3.9 days versus 4.6 days for the QSP group; P = 0.007). The overall proportions of reported side effects were similar in the two groups, but patients in the M group had a significantly higher rate of central nervous system disturbances (29.0% versus 9.6% for the QSP group; P < 0.001).

Antimalarial combinations

Multidrug resistance has rendered monotherapy for malaria useless in most parts of the world, and has also compromised the usefulness of many of the available combination chemotherapies. New antimalarial regimens are, therefore, urgently needed. We review the various antimalarial combinations that can be used to treat otherwise drug-resistant disease, and discuss what defines an ideal antimalarial combination regimen.

Fosmidomycin for the treatment of malaria

In malaria parasites, isoprenoids are synthesised by the mevalonate independent 1-deoxy- D-xylulose 5-phosphate (DOXP) pathway. Fosmidomycin, a natural antibiotic originally developed for the treatment of bacterial infections, represents an inhibitor of DOXP reductoisomerase, an essential enzyme of this pathway. In recent clinical studies it was shown that fosmidomycin is effective in curing uncomplicated Plasmodium falciparum malaria in humans. The treatment was well tolerated and resulted in a fast parasite and fever clearance. However, the high rate of recrudescence precludes the use of fosmidomycin as a monotherapy. In drug combination studies, synergy of fosmidomycin with clindamycin was observed. Clinical studies with a fosmidomycin-clindamycin combination are currently ongoing.

In vitro and in vivo synergy of fosmidomycin, a novel antimalarial drug, with clindamycin

Fosmidomycin acts through inhibition of 1-deoxy-D-xylulose 5-phosphate (DOXP) reductoisomerase, a key enzyme of the nonmevalonate pathway of isoprenoid biosynthesis. It possesses potent antimalarial activity in vitro and in murine malaria. In a recent clinical study, fosmidomycin was effective and well tolerated in the treatment of patients with acute uncomplicated Plasmodium falciparum malaria but resulted in an unacceptably high rate of recrudescence. In order to identify a potential combination partner, the interaction of fosmidomycin with a number of antimalarial drugs in current use was investigated in a series of in vitro experiments. Synergy was observed between fosmidomycin and the lincosamides, lincomycin and clindamycin. The efficacy of a combination of fosmidomycin and clindamycin was subsequently demonstrated in the Plasmodium vinckei mouse model.