First assessment in humans of the safety, tolerability, pharmacokinetics, and ex vivo pharmacodynamic antimalarial activity of the new artemisinin derivative artemisone.
In preclinical studies, artemisone (BAY 44-9585), a new artemisinin derivative, was shown to possess enhanced efficacy over artesunate, and it does not possess the neurotoxicity characteristic of the current artemisinins. In a phase I program with double-blind, randomized, placebo-controlled, single and multiple ascending oral-dose studies, we evaluated the safety, tolerability, pharmacokinetics, and ex vivo pharmacodynamic antimalarial activity of artemisone. Single doses (10, 20, 30, 40, and 80 mg) and multiple doses (40 and 80 mg daily for 3 days) of artemisone were administered orally to healthy subjects. Plasma concentrations of artemisone and its metabolites were measured by liquid chromatography/tandem mass spectrometry (LC/MS-MS). Artemisone was well tolerated, with no serious adverse events and no clinically relevant changes in laboratory and vital parameters. The pharmacokinetics of artemisone over the 10- to 80-mg range demonstrated dose linearity. After the single 80-mg dose, artemisone had a geometric mean maximum concentration of 140.2 ng/ml (range, 86.6 to 391.0), a short elimination half-life (t(1/2)) of 2.79 h (range, 1.56 to 4.88), a high oral clearance of 284.1 liters/h (range, 106.7 to 546.7), and a large volume of distribution of 14.50 liters/kg (range, 3.21 to 51.58). Due to artemisone's short t(1/2), its pharmacokinetics were comparable after single and multiple dosing. Plasma samples taken after multiple dosing showed marked ex vivo pharmacodynamic antimalarial activities against two multidrug-resistant Plasmodium falciparum lines. Artemisone equivalent concentrations measured by bioassay revealed higher activity than artemisone measured by LC/MS-MS, confirming the presence of active metabolites. Comparable to those of other artemisinin's, artemisone's t(1/2) is well suited for artemisinin-based combination therapy for the treatment of P. falciparum malaria.
Clinical Pharmacology, Bayer Health Care AG, Wuppertal, Germany. johannes.nagelschmitz@bayerhealthcare.com
Johannes
J
Nagelschmitz
Barbara
B
Voith
Georg
G
Wensing
Axel
A
Roemer
Burkhard
B
Fugmann
Richard K
RK
Haynes
Barbara M
BM
Kotecka
Karl H
KH
Rieckmann
Michael D
MD
Edstein
D000328:Adult; D000818:Animals; D000962:Antimalarials / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics / Q000494:pharmacology; D037621:Artemisinins / Q000008:administration & dosage / Q000009:adverse effects / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D004311:Double-Blind Method; D006801:Humans; D008297:Male; D021261:Parasitic Sensitivity Tests; D010963:Plasmodium falciparum / Q000187:drug effects* / Q000254:growth & development; D016896:Treatment Outcome
D000962:Antimalarials; D037621:Artemisinins; C514498:artemisone