Pyronaridine-Artesunate versus Chloroquine in Patients with Acute Plasmodium vivax Malaria: A Randomized, Double-Blind, Non-Inferiority Trial

BACKGROUND: New antimalarials are needed for P. vivax and P. falciparum malaria. This study compared the efficacy and safety of pyronaridine-artesunate with that of chloroquine for the treatment of uncomplicated P. vivax malaria. METHODS AND FINDINGS: This phase III randomized, double-blind, non-inferiority trial included five centers across Cambodia, Thailand, India, and Indonesia. In a double-dummy design, patients (aged >3-≤ 60 years) with microscopically confirmed P. vivax mono-infection were randomized (1:1) to receive pyronaridine-artesunate (target dose 7.2:2.4 mg/kg to 13.8:4.6 mg/kg) or chloroquine (standard dose) once daily for three days. Each treatment group included 228 randomized patients. Outcomes for the primary endpoint, Day-14 cure rate in the per-protocol population, were 99.5%, (217/218; 95%CI 97.5, 100) with pyronaridine-artesunate and 100% (209/209; 95%CI 98.3, 100) with chloroquine. Pyronaridine was non-inferior to chloroquine: treatment difference -0.5% (95%CI -2.6, 1.4), i.e., the lower limit of the 2-sided 95%CI for the treatment difference was greater than -10%. Pyronaridine-artesunate cure rates were non-inferior to chloroquine for Days 21, 28, 35 and 42. Parasite clearance time was shorter with pyronaridine-artesunate (median 23.0 h) versus chloroquine (32.0 h; p<0.0001), as was fever clearance time (median 15.9 h and 23.8 h, respectively; p = 0.0017). Kaplan-Meier estimates of post-baseline P. falciparum infection incidence until Day 42 were 2.5% with pyronaridine-artesunate, 6.1% with chloroquine (p = 0.048, log-rank test). Post-baseline P. vivax or P. falciparum infection incidence until Day 42 was 6.8% and 12.4%, respectively (p = 0.022, log rank test). There were no deaths. Adverse events occurred in 92/228 (40.4%) patients with pyronaridine-artesunate and 72/228 (31.6%) with chloroquine. Mild and transient increases in hepatic enzymes were observed for pyronaridine-artesunate. CONCLUSION: Pyronaridine-artesunate efficacy in acute uncomplicated P. vivax malaria was at least that of chloroquine. As pyronaridine-artesunate is also efficacious against P. falciparum malaria, this combination has potential utility as a global antimalarial drug. TRIAL REGISTRATION: Clinicaltrials.gov NCT00440999

Pyronaridine-Artesunate Versus Mefloquine Plus Artesunate for Malaria.

\ud \ud Pyronaridine-artesunate is an artemisinin-based combination therapy under evaluation for the treatment of Plasmodium falciparum and P. vivax malaria. We conducted a phase 3, open-label, multicenter, noninferiority trial that included 1271 patients between 3 and 60 years of age from Asia (81.3%) or Africa (18.7%) with microscopically confirmed, uncomplicated P. falciparum malaria. Patients underwent randomization for treatment with a fixed-dose combination of 180 mg of pyronaridine and 60 mg of artesunate or with 250 mg of mefloquine plus 100 mg of artesunate. Doses were calculated according to body weight and administered once daily for 3 days. Pyronaridine-artesunate was noninferior to mefloquine plus artesunate for the primary outcome: adequate clinical and parasitologic response in the per-protocol population on day 28, corrected for reinfection with the use of polymerase-chain-reaction (PCR) genotyping. For this outcome, efficacy in the group receiving pyronaridine-artesunate was 99.2% (743 of 749 patients; 95% confidence interval [CI], 98.3 to 99.7) and that in the group receiving mefloquine plus artesunate was 97.8% (360 of 368 patients; 95% CI, 95.8 to 99.1), with a treatment difference of 1.4 percentage points (95% CI, 0.0 to 3.5; P=0.05). In the intention-to-treat population, efficacy on day 42 in the group receiving pyronaridine-artesunate was 83.1% (705 of 848 patients; 95% CI, 80.4 to 85.6) and that in the group receiving mefloquine plus artesunate was 83.9% (355 of 423 patients; 95% CI, 80.1 to 87.3). In Cambodia, where there were 211 study patients, the median parasite clearance time was prolonged for both treatments: 64 hours versus 16.0 to 38.9 hours in other countries (P<0.001, on the basis of Kaplan-Meier estimates). Kaplan-Meier estimates of the recrudescence rate in the intention-to-treat population in Cambodia until day 42 were higher with pyronaridine-artesunate than with mefloquine plus artesunate (10.2% [95% CI, 5.4 to 18.6] vs. 0%; P=0.04 as calculated with the log-rank test), but similar for the other countries combined (4.7% [95% CI, 3.3 to 6.7] and 2.8% [95% CI, 1.5 to 5.3], respectively; P=0.24). Elevated levels of aminotransferases were observed in those receiving pyronaridine-artesunate. Two patients receiving mefloquine plus artesunate had seizures. Fixed-dose pyronaridine-artesunate was efficacious in the treatment of uncomplicated P. falciparum malaria. In Cambodia, extended parasite clearance times were suggestive of in vivo resistance to artemisinin. (Funded by Shin Poong Pharmaceutical Company and the Medicines for Malaria Venture; ClinicalTrials.gov number, NCT00403260.)

The de-sequestering capacity of sevuparin in <i>P</i>. <i>falciparum</i> infected patients.

<p>A total of 44 patients were included in the efficacy part of the trial and were treated with oral atovaquone/proguanil with or without adjunctive treatment in the form of short i.v. infusions of sevuparin. The numbers of trophozoite and schizont IEs were estimated in the peripheral blood samples on thin and thick films that were taken at time points 0, 1, 2, 3, 4, 6, 8, 10, and 11 h and thereafter every 6 h until two consecutive blood samples were parasite negative. The relative numbers were calculated from the number of trophozoite and schizont IEs at one time point related to the baseline number of trophozoite and schizont IEs at time point 0 h (immediately prior to the first dose of sevuparin), and the mean was measured based on all subjects in one group. The red dotted line represents the sevuparin treated patients, and the blue line represents the control patients. Logarithmic y- axis is used. Significantly (p<0.05) higher numbers of trophozoite and schizont IEs were found in the sevuparin treated patients at time point 1 h (p = 0.0322). In a, the relative numbers (mean ± SD) of trophozoite and schizont parasites in the two study groups up to H30 are presented. In b, the detailed relative changes in the number of trophozoite and schizont parasites (mean ± SD) during the first 12 hours after the first injection of sevuparin are shown. In c, individual effects of sevuparin on the number of trophozoites and schizont parasites per patient is shown. The grey arrows indicate the periodic sevuparin infusions.</p

Sevuparin inhibits merozoite invasion of <i>P</i>. <i>falciparum</i> clones, strains and fresh isolates <i>in vitro</i> at low concentrations, independently of parasite origin or phenotype.

<p>The invasion blocking capacity of sevuparin in 34 <i>in vitro</i> propagated <i>P</i>. <i>falciparum</i> isolates expressed as IC50. The inhibitory capacity of sevuparin was titrated in double dilution steps between 0.125 μg/mL and 1 mg sevuparin/mL culture. Ten laboratory isolates were either sensitive (3D7, 3D7PG12, Dd2, HB3) or resistant (R29, TM180, TM284, F32, 7G8, FCR3S1.2) to chloroquine. Three parasites of the W2mef background carried disrupted genes for EBA 140, EBA 175 or EBA 181 (EBA-KO). W2mef is a cloned line of parasites derived from the Indochina III-CDC strain. Of the fresh primary isolates 11 were from Ugandan children with either severe (dot) or uncomplicated (square) malaria and six isolates were from adults infected in Ethiopia/Eritrea, Kenya or Niger. Four Cambodian isolates were sensitive or resistant to artemisinin (red-circled square; IPC-4884, Pursut, artemisinin resistant (RSA 0-3h: 6,5%) and IPC 4912 artemisinin resistant (red circled square; RSA 0–3 h: 49%). ICP 5188 Rattanakiri and IPC 3663 Pailin were artemisinin sensitive (square).</p

Anticoagulant activity of sevuparin.

<p>Anticoagulant activity of sevuparin.</p

Sevuparin lowers the relative mean number of ring-stage IEs after a single sevuparin infusion in <i>P</i>. <i>falciparum</i> infected patients.

<p>A total of 44 patients were included in the efficacy part of the trial (part 2) and were treated with oral atovaquone/proguanil with or without adjunctive treatment in the form of i.v. infusions of sevuparin. The relative numbers were calculated from the number of ring IEs at one time point related to the baseline value of ring IEs at time point 0 h (immediately prior to the first dose of sevuparin), and the mean was measured based on all subjects in one group. a, The mean relative numbers (mean ± SD) of ring stage parasites in the two study groups from 0 h to 30 h. The numbers of ring-stage IEs were estimated in peripheral blood samples on thin and thick films that were taken at time points 0, 1, 2, 3, 4, 6, 8, 10, and 11 h and thereafter every 6 h until two consecutive blood samples were parasite negative. The red dotted line represents the patients treated with sevuparin (3 mg/kg) and oral atovaquone/proguanil, and the blue line represents the control patients who were given only oral atovaquone/proguanil, a logarithmic y-axis is used. Significantly lower levels of ring stage IEs were found in the sevuparin treated patients at time points 1 h (p = 0.0223), 2 h (p = 0.0246), 3 h (p = 0.0027), 4 h (p = 0.0278), and 6 h (p = 0.0346). (An outlier appears in the data but does not drive the difference as the statistical significant difference between the two groups remains even if data from this patient is excluded from the analysis since the tests used are non-parametric which are thus very robust against divergent.) b, Detailed mean relative changes in the number (mean ± SD) of ring stage parasites during the first 12 hours after the first injection of sevuparin. c, Numbers of ring-stage IEs levels in the individual patients. Oragne arrow indicate an outlier. Grey arrows indicate the short i.v. sevuparin infusions over five minutes.</p

Study design of phase I/II study in patients with uncomplicated <i>falciparum</i> malaria-TSM02.

<p>a, Overview of study design and dosing regimen for all patients in part 1. b, Overview of study design and dosing regimen for patients in part 2 randomized to the anti-malarial regimen (atovaquone and proguanil) alone or sevuparin plus anti-malarial regimen (atovaquone/proguanil).</p