Longitudinal changes in iron homeostasis in human experimental and clinical malaria.

BACKGROUND: The interaction between iron status and malaria is incompletely understood. We evaluated longitudinal changes in iron homeostasis in volunteers enrolled in malaria volunteer infection studies (VIS) and in Malaysian patients with falciparum and vivax malaria. METHODS: We retrieved data and samples from 55 participants (19 female) enrolled in malaria VIS, and 171 patients (45 female) with malaria and 30 healthy controls (13 female) enrolled in clinical studies in Malaysia. Ferritin, hepcidin, erythropoietin, and soluble transferrin receptor (sTfR) were measured by ELISA. FINDINGS: In the VIS, participants' parasitaemia was correlated with baseline mean corpuscular volume (MCV), but not iron status (ferritin, hepcidin or sTfR). Ferritin, hepcidin and sTfR all increased during the VIS. Ferritin and hepcidin normalised by day 28, while sTfR remained elevated. In VIS participants, baseline ferritin was associated with post-treatment increases in liver transaminase levels. In Malaysian patients with malaria, hepcidin and ferritin were elevated on admission compared to healthy controls, while sTfR increased following admission. By day 28, hepcidin had normalised; however, ferritin and sTfR both remained elevated. INTERPRETATION: Our findings demonstrate that parasitaemia is associated with an individual's MCV rather than iron status. The persistent elevation in sTfR 4 weeks post-infection in both malaria VIS and clinical malaria may reflect a causal link between malaria and iron deficiency. FUNDING: National Health and Medical Research Council (Program Grant 1037304, Project Grants 1045156 and 1156809; Investigator Grants 2016792 to BEB, 2016396 to JCM, 2017436 to MJG); US National Institute of Health (R01-AI116472-03); Malaysian Ministry of Health (BP00500420).

Randomized, placebo-controlled, double-blind phase I trial of co-administered pyronaridine and piperaquine in healthy adults of sub-Saharan origin.

Drug resistance to sulfadoxine-pyrimethamine and amodiaquine threatens the efficacy of malaria chemoprevention interventions in children and pregnant women. Combining pyronaridine (PYR) and piperaquine (PQP), both components of approved antimalarial therapies, has the potential to protect vulnerable populations from severe malaria. This randomized, double-blind, placebo-controlled (double-dummy), parallel-group, single site phase I study in healthy adult males or females of Black sub-Saharan African ancestry investigated the safety, tolerability, and pharmacokinetics of PYR + PQP (n = 15), PYR + placebo (n = 8), PQP + placebo (n = 8), and double placebo (n = 6) administered orally once daily for 3 days at the registered dose for the treatment of uncomplicated malaria. All participants completed the study. Forty-five adverse events were reported in 26 participants, most (41/45) were mild/moderate in severity, with no serious adverse events, deaths, or study withdrawals. Adverse events were reported in 66.7% (10/15) of participants administered PYR + PQP, 87.5% (7/8) with PYR + placebo, 50.0% (4/8) with PQP + placebo, and 83.3% (5/6) with placebo. For PYR containing regimens, five of 23 participants had asymptomatic transient increases in alanine and/or aspartate aminotransferase. With PQP containing regimens, four of 23 participants had mild Fridericia-corrected QT interval prolongation. Liver enzyme elevations and prolonged QTc interval were consistent with observations for PYR-artesunate and dihydroartemisinin-PQP, respectively, administered to healthy adults and malaria patients. Increases in PYR and PQP exposures were observed following co-administration versus placebo, with substantial interparticipant variability. The findings suggest that PYR + PQP may have potential in chemoprevention strategies. Further studies are needed in the target populations to assess chemoprotective efficacy and define the benefit-risk profile, with special considerations regarding hepatic and cardiac safety.

Longitudinal changes in iron homeostasis in human experimental and clinical malaria.

Background: The interaction between iron deficiency and malaria is incompletely understood. We evaluated longitudinal changes in iron homeostasis in volunteers enrolled in malaria volunteer infection studies (VIS) and in Malaysian patients with falciparum and vivax malaria. Methods: We retrieved samples and associated data from 55 participants enrolled in malaria VIS, and 171 malaria patients and 30 healthy controls enrolled in clinical studies in Malaysia. Ferritin, hepcidin, erythropoietin, and soluble transferrin receptor (sTfR) were measured by ELISA. Results: In the VIS, participants' parasitaemia was correlated with baseline mean corpuscular volume (MCV), but not iron status (ferritin, hepcidin or sTfR). Ferritin, hepcidin and sTfR all increased during the VIS. Ferritin and hepcidin normalised by day 28, while sTfR remained elevated. In VIS participants, baseline iron status (ferritin) was associated with post-treatment increases in liver transaminase levels. In Malaysian malaria patients, hepcidin and ferritin were elevated on admission compared to healthy controls, while sTfR increased following admission. Hepcidin normalised by day 28; however, ferritin and sTfR both remained elevated 4 weeks following admission. Conclusion: Our findings demonstrate that parasitaemia is associated with an individual's MCV rather than iron status. The persistent elevation in sTfR 4 weeks post-infection in both malaria VIS and clinical malaria may reflect a causal link between malaria and iron deficiency.

Unanticipated CNS Safety Signal in a Placebo-Controlled, Randomized Trial of Co-Administered Atovaquone-Proguanil and Amodiaquine.

Atovaquone-proguanil (ATV-PG) plus amodiaquine (AQ) has been considered as a potential replacement for sulfadoxine-pyrimethamine plus AQ for seasonal malaria chemoprevention in African children. This randomized, double-blind, placebo-controlled, parallel group study assessed the safety, tolerability, and pharmacokinetics (PKs) of ATV-PG plus AQ in healthy adult males and females of Black sub-Saharan African origin. Participants were randomized to four treatment groups: ATV-PG/AQ (n = 8), ATV-PG/placebo (n = 12), AQ/placebo (n = 12), and placebo/placebo (n = 12). Treatments were administered orally once daily for 3 days (days 1-3) at daily doses of ATV-PQ 1000/400 mg and AQ 612 mg. Co-administration of ATV-PG/AQ had no clinically relevant effect on PK parameters for ATV, PG, the PG metabolite cycloguanil, AQ, or the AQ metabolite N-desethyl-amodiaquine. Adverse events occurred in 8 of 8 (100%) of participants receiving ATV-PG/AQ, 11 of 12 (91.7%) receiving ATV-PG, 11 of 12 (91.7%) receiving AQ, and 3 of 12 (25%) receiving placebo. The safety and tolerability profiles of ATV-PG and AQ were consistent with previous reports. In the ATV-PG/AQ group, 2 of 8 participants experienced extrapyramidal adverse effects (EPAEs) on day 3, both psychiatric and physical, which appeared unrelated to drug plasma PKs or cytochrome P450 2C8 phenotype. Although rare cases are reported with AQ administration, the high incidence of EPAE was unexpected in this small study. Owing to the unanticipated increased frequency of EPAE observed, the combination of ATV-PQ plus AQ is not recommended for further evaluation in prophylaxis of malaria in African children.

Safety, tolerability, pharmacokinetics, and antimalarial efficacy of a novel Plasmodium falciparum ATP4 inhibitor SJ733: a first-in-human and induced blood-stage malaria phase 1a/b trial.

BACKGROUND: (+)-SJ000557733 (SJ733) is a novel, orally bioavailable inhibitor of Plasmodium falciparum ATP4. In this first-in-human and induced blood-stage malaria phase 1a/b trial, we investigated the safety, tolerability, pharmacokinetics, and antimalarial activity of SJ733 in humans. METHODS: The phase 1a was a single-centre, dose-escalation, first-in-human study of SJ733 allowing modifications to dose increments and dose-cohort size on the basis of safety and pharmacokinetic results. The phase 1a took place at St Jude Children's Research Hospital and at the University of Tennessee Clinical Research Center (Memphis, TN, USA). Enrolment in more than one non-consecutive dose cohort was allowed with at least 14 days required between doses. Participants were fasted in seven dose cohorts and fed in one 600 mg dose cohort. Single ascending doses of SJ733 (75, 150, 300, 600, 900, or 1200 mg) were administered to participants, who were followed up for 14 days after SJ733 dosing. Phase 1a primary endpoints were safety, tolerability, and pharmacokinetics of SJ733, and identification of an SJ733 dose to test in the induced blood-stage malaria model. The phase 1b was a single-centre, open-label, volunteer infection study using the induced blood-stage malaria model in which fasted participants were intravenously infected with blood-stage P falciparum and subsequently treated with a single dose of SJ733. Phase 1b took place at Q-Pharm (Herston, QLD, Australia) and was initiated only after phase 1a showed that exposure exceeding the threshold minimum exposure could be safely achieved in humans. Participants were inoculated on day 0 with P falciparum-infected human erythrocytes (around 2800 parasites in the 150 mg dose cohort and around 2300 parasites in the 600 mg dose cohort), and parasitaemia was monitored before malaria inoculation, after inoculation, immediately before SJ733 dosing, and then post-dose. Participants were treated with SJ733 within 24 h of reaching 5000 parasites per mL or at a clinical score higher than 6. Phase 1b primary endpoints were calculation of a parasite reduction ratio (PRR48) and parasite clearance half-life, and safety and tolerability of SJ733 (incidence, severity, and drug-relatedness of adverse events). In both phases of the trial, SJ733 hydrochloride salt was formulated as a powder blend in capsules containing 75 mg or 300 mg for oral administration. Healthy men and women (of non-childbearing potential) aged 18-55 years were eligible for both studies. Both studies are registered with ClinicalTrials.gov (NCT02661373 for the phase 1a and NCT02867059 for the phase 1b). FINDINGS: In the phase 1a, 23 healthy participants were enrolled and received one to three non-consecutive doses of SJ733 between March 14 and Dec 7, 2016. SJ733 was safe and well tolerated at all doses and in fasted and fed conditions. 119 adverse events were recorded: 54 (45%) were unrelated, 63 (53%) unlikely to be related, and two (2%) possibly related to SJ733. In the phase 1b, 17 malaria-naive, healthy participants were enrolled. Seven participants in the 150 mg dose cohort were inoculated and dosed with SJ733. Eight participants in the 600 mg dose cohort were inoculated, but two participants could not be dosed with SJ733. Two additional participants were subsequently inoculated and dosed with SJ733. SJ733 exposure increased proportional to the dose through to the 600 mg dose, then was saturable at higher doses. Fasted participants receiving 600 mg exceeded the target area under the concentration curve extrapolated to infinity (AUC0-∞) of 13 000 µg × h/L (median AUC0-∞ 24 283 [IQR 16 135-31 311] µg × h/L, median terminal half-life 17·4 h [IQR 16·1-24·0], and median timepoint at which peak plasma concentration is reached 1·0 h [0·6-1·3]), and this dose was tested in the phase 1b. All 15 participants dosed with SJ733 had at least one adverse event. Of the 172 adverse events recorded, 128 (74%) were mild. The only adverse event attributed to SJ733 was mild bilateral foot paraesthesia that lasted 3·75 h and resolved spontaneously. The most common adverse events were related to malaria. Based on parasite clearance half-life, the derived log10PRR48 and corresponding parasite clearance half-lives were 2·2 (95% CI 2·0-2·5) and 6·47 h (95% CI 5·88-7·18) for 150 mg, and 4·1 (3·7-4·4) and 3·56 h (3·29-3·88) for 600 mg. INTERPRETATION: The favourable pharmacokinetic, tolerability, and safety profile of SJ733, and rapid antiparasitic effect support its development as a fast-acting component of combination antimalarial therapy. FUNDING: Global Health Innovative Technology Fund, Medicines for Malaria Venture, and the American Lebanese Syrian Associated Charities.

A Randomized Trial Evaluating the Prophylactic Activity of DSM265 Against Preerythrocytic Plasmodium falciparum Infection During Controlled Human Malarial Infection by Mosquito Bites and Direct Venous Inoculation.

Background: DSM265 is a selective inhibitor of Plasmodium dihydroorotate dehydrogenase that fully protected against controlled human malarial infection (CHMI) by direct venous inoculation of Plasmodium falciparum sporozoites when administered 1 day before challenge and provided partial protection when administered 7 days before challenge. Methods: A double-blinded, randomized, placebo-controlled trial was performed to assess safety, tolerability, pharmacokinetics, and efficacy of 1 oral dose of 400 mg of DSM265 before CHMI. Three cohorts were studied, with DSM265 administered 3 or 7 days before direct venous inoculation of sporozoites or 7 days before 5 bites from infected mosquitoes. Results: DSM265-related adverse events consisted of mild-to-moderate headache and gastrointestinal symptoms. DSM265 concentrations were consistent with pharmacokinetic models (mean area under the curve extrapolated to infinity, 1707 µg*h/mL). Placebo-treated participants became positive by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and were treated 7-10 days after CHMI. Among DSM265-treated subjects, 2 of 6 in each cohort were sterilely protected. DSM265-treated recipients had longer times to development of parasitemia than placebo-treated participants (P < .004). Conclusions: This was the first CHMI study of a novel antimalarial compound to compare direct venous inoculation of sporozoites and mosquito bites. Times to qRT-PCR positivity and treatment were comparable for both routes. DSM265 given 3 or 7 days before CHMI was safe and well tolerated but sterilely protected only one third of participants.

DSM265 for Plasmodium falciparum chemoprophylaxis: a randomised, double blinded, phase 1 trial with controlled human malaria infection.

BACKGROUND: A drug for causal (ie, pre-erythrocytic) prophylaxis of Plasmodium falciparum malaria with prolonged activity would substantially advance malaria control. DSM265 is an experimental antimalarial that selectively inhibits the parasite dihydroorotate dehydrogenase. DSM265 shows in vitro activity against liver and blood stages of P falciparum. We assessed the prophylactic activity of DSM265 against controlled human malaria infection (CHMI). METHODS: At the Institute of Tropical Medicine, Eberhard Karls University (Tübingen, Germany), healthy, malaria-naive adults were allocated to receive 400 mg DSM265 or placebo either 1 day (cohort 1A) or 7 days (cohort 2) before CHMI by direct venous inoculation (DVI) of 3200 aseptic, purified, cryopreserved P falciparum sporozoites (PfSPZ Challenge; Sanaria Inc, Rockville, MD, USA). An additional group received daily atovaquone-proguanil (250-100 mg) for 9 days, starting 1 day before CHMI (cohort 1B). Allocation to DSM265, atovaquone-proguanil, or placebo was randomised by an interactive web response system. Allocation to cohort 1A and 1B was open-label, within cohorts 1A and 2, allocation to DSM265 and placebo was double-blinded. All treatments were given orally. Volunteers were treated with an antimalarial on day 28, or when parasitaemic, as detected by thick blood smear (TBS) microscopy. The primary efficacy endpoint was time-to-parasitaemia, assessed by TBS. All participants receiving at least one dose of chemoprophylaxis or placebo were considered for safety, those receiving PfSPZ Challenge for efficacy analyses. Log-rank test was used to compare time-to-parasitemia between interventions. The trial was registered with ClinicalTrials.gov, number NCT02450578. FINDINGS: 22 participants were enrolled between Oct 23, 2015, and Jan 18, 2016. Five participants received 400 mg DSM265 and two participants received placebo 1 day before CHMI (cohort 1A), six participants received daily atovaquone-proguanil 1 day before CHMI (cohort 1B), and six participants received 400 mg DSM265 and two participants received placebo 7 days before CHMI (cohort 2). Five of five participants receiving DSM265 1 day before CHMI and six of six in the atovaquone-proguanil cohort were protected, whereas placebo recipients (two of two) developed malaria on days 11 and 14. When given 7 days before CHMI, three of six volunteers receiving DSM265 became TBS positive on days 11, 13, and 24. The remaining three DSM265-treated, TBS-negative participants of cohort 2 developed transient submicroscopic parasitaemia. Both participants receiving placebo 7 days before CHMI became TBS positive on day 11. The only possible DSM265-related adverse event was a moderate transient elevation in serum bilirubin in one participant. INTERPRETATION: A single dose of 400 mg DSM265 was well tolerated and had causal prophylactic activity when given 1 day before CHMI. Future trials are needed to investigate further the use of DSM265 for the prophylaxis of malaria. FUNDING: Global Health Innovative Technology Fund, Wellcome Trust, Bill & Melinda Gates Foundation through Medicines for Malaria Venture, and the German Center for Infection Research.

Evaluation of the pharmacokinetics and safety of bosutinib in patients with chronic hepatic impairment and matched healthy subjects.

PURPOSE: Bosutinib, a dual Src/Abl kinase inhibitor in development for treatment of chronic myeloid leukemia, is primarily metabolized by the CYP3A4 hepatic enzyme. This study evaluated the pharmacokinetics and safety of bosutinib in patients with chronic hepatic impairment and matched healthy subjects. METHODS: Hepatically impaired patients were aged 18-65 years and of Child-Pugh classes A, B, or C; healthy subjects were matched by age, sex, body mass index, and smoking habits. A single oral dose of bosutinib 200 mg was administered on day 1 within 5 min after completion of breakfast. RESULTS: Compared with healthy subjects (n = 9), maximal plasma concentration (C(max)) and area under the curve increased 2.42-fold and 2.25-fold in Child-Pugh A (n = 6), 1.99-fold and 2.0-fold in Child-Pugh B (n = 6), and 1.52-fold and 1.91-fold in Child-Pugh C patients (n = 6). Time to C(max) decreased from 4 h in healthy subjects to 2.5, 2.0, and 1.5 h in Child-Pugh A, B, and C patients, respectively; the elimination half-life increased from 55 h in healthy subjects to 86, 113, and 111 h in Child-Pugh A, B, and C patients. Bosutinib oral clearance was lower in hepatically impaired patients compared with healthy subjects. Frequently reported adverse events included prolonged QTc interval (37.0%, n = 10), nausea (11.1%, n = 3), and vomiting (7.4%, n = 2). CONCLUSIONS: A single oral dose of bosutinib 200 mg showed acceptable tolerability in healthy subjects and in patients with mild, moderate, or severe chronic hepatic impairment.

Ascending single-dose study of the safety profile, tolerability, and pharmacokinetics of bosutinib coadministered with ketoconazole to healthy adult subjects.

BACKGROUND: Bosutinib (SKI-606) is an orally bioavailable, competitive tyrosine kinase inhibitor that selectively targets both Src and Abl tyrosine kinases. Bosutinib is metabolized primarily through the cytochrome P450 3A4 pathway. Inhibition of bosutinib metabolism by coadministration with the potent cytochrome P450 3A4 inhibitor ketoconazole could potentially increase plasma concentrations of bosutinib, allowing for the study of bosutinib tolerability at supratherapeutic concentrations in a healthy subject population. OBJECTIVE: This study assessed the safety profile, tolerability, and pharmacokinetics of different dose combinations of bosutinib coadministered with ketoconazole in healthy adults, and determined whether supratherapeutic concentrations of bosutinib can be achieved with ketoconazole. METHODS: This was a randomized, Phase I, double-blind, placebo-controlled, sequential-group study conducted in healthy adults. Single oral doses of bosutinib 100, 200, 300, 400, 500, and 600 mg or placebo were administered with ketoconazole and food on day 1; daily single oral doses of ketoconazole 400 mg were administered on days -1 and 1 through 4. RESULTS: Forty-eight subjects were enrolled. Their mean (SD) age was 32.0 (10.7) years (range, 18-50 years). The majority of the subjects (n = 44 [92%]) were white, 2 (4%) were black or African American, and 2 (4%) were of other races. Bosutinib was associated with acceptable tolerability at doses from 100 to 600 mg, with adverse events either mild (n = 30 [63%]) or moderate (n = 12 [25%]) in severity; no subject discontinued treatment due to adverse events, and no serious events were reported. Mean (SD) values for bosutinib 100 to 600 mg ranged from 58.4 (13.3) to 426 (100) ng/mL for C(max) and 2980 (802) to 23,000 (4020) ng·h/mL for AUC(0-∞); mean AUC(0-24) and AUC(0-last) ranged from 876 (234) to 7080 (1640) ng· h/mL and from 2740 (854) to 22,200 (3630) ng · h/mL, respectively. C(max) and AUC were linear and dose proportional. Mean C(max) at 600 mg was 2.1-fold higher than the steady-state C(max) previously observed for patients with chronic myelogenous leukemia who received bosutinib 500 mg once daily with food. CONCLUSIONS: Single doses of bosutinib up to 600 mg coadministered with multiple doses of ketoconazole were acceptably well tolerated in this small, selected group of healthy male volunteers. In addition, supratherapeutic exposure was achieved within this range for bosutinib when coadministered with ketoconazole. ClinicalTrials.gov identifier: NCT00777530.

A phase I ascending single-dose study of the safety, tolerability, and pharmacokinetics of bosutinib (SKI-606) in healthy adult subjects.

PURPOSE: Bosutinib (SKI-606), a dual Src/Abl tyrosine kinase inhibitor, is in clinical development for the treatment of patients with chronic myelogenous leukemia (CML). To support clinical development, we conducted a dose-escalation and food-effect evaluation of safety, tolerability, and pharmacokinetics (PK) of bosutinib in healthy adults. METHODS: This was a randomized, double-blind, placebo-controlled, single-ascending dose, sequential-group study of oral bosutinib. Subjects randomly received bosutinib 200, 400, 600, and 800 mg with food; 200 and 400 mg without food; or placebo. Plasma concentrations were determined by a liquid chromatography-tandem mass spectrometry assay. Non-compartmental PK analyses were performed, and power models assessed dose linearity. RESULTS: Of 55 enrolled subjects, 33 (81%) subjects had adverse events (AEs) after receiving bosutinib. Common AEs included diarrhea (39%), nausea (29%), and headache (22%). Bosutinib 200-600 mg with food was safe and well tolerated. Bosutinib exposures (C (max) and AUC) were linear and dose proportional from 200 to 800 mg with food. Absorption was relatively slow; median time to C (max) was 6 h. Apparent volume of distribution (V (z)/F) was 131-214 L/kg, mean apparent clearance (CL/F) was 2.25-3.81 L/h/kg, and mean terminal elimination half-life (t (1/2)) was 32-39 h. Preliminary food effect assessment showed that exposure to bosutinib increased by ~2.52-fold (P = 0.002) for C (max) and ~2.28-fold (P = 0.002) for AUC when 200 mg bosutinib was administered with food compared with administration under fasting conditions; administration of 400 mg bosutinib with food increased AUC by ~1.5-fold (P = 0.037). Approximately 1% of administered dose was excreted in urine. CONCLUSIONS: Bosutinib 200-600 mg with food was safe and well tolerated. Under fed conditions, bosutinib exposures were linear and dose proportional, and C (max) increased by ~1.5-fold. The t (1/2) supported a once-daily dosing regimen.