Pharmacokinetics of a Tumor Necrosis Factor- Phosphorothioate 2 -o- (2-methoxyethyl) Modified Antisense Oligonucleotide: Comparison across Species

The pharmacokinetics of a 2 -O-(2-methoxyethyl)-ribose modified phosphorothioate oligonucleotide, ISIS 104838 (human tumor necrosis factorantisense), have been characterized in mouse, rat, dog, monkey, and human. Plasma pharmacokinetics after i.v. administration exhibited relatively rapid distribution from plasma to tissues with a distribution half-life estimated from approximately 15 to 45 min in all species. Absorption after s.c. injection was high (80–100%), and absorption after intrajejunal administration in proprietary formulations was as high as 10% bioavailability compared with i.v. administration. Urinary excretion of the parent drug was low, with less than 1% of the administered dose excreted in urine after i.v. infusion in monkeys at clinically relevant doses (<5 mg/ kg). ISIS 104838 is highly bound to plasma proteins, likely preventing renal filtration. However, shortened oligonucleotide metabolites of ISIS 104838 lose their affinity to bind plasma proteins. Thus, excretion of radiolabel (mostly as metabolites) in urine (75%) and feces (5–10%) was nearly complete by 90 days. Elimination of ISIS 104838 from tissue was slow (multiple days) for all species, depending on the tissue or organ. The highest concentrations of ISIS 104838 in tissues were seen in kidney, liver, lymph nodes, bone marrow, and spleen. In general, concentrations of ISIS 104838 were higher in monkey tissues than in rodents at body weight-equivalent doses. Plasma pharmacokinetics scale well across species as a function of body weight alone. This favorable pharmacokinetic profile for ISIS 104838 provides guidance for clinical development and appears to support infrequent and convenient dose administration. The antisense oligonucleotide chemistry that is most advanced in development today for medical treatment is that of the phosphorothioate oligodeoxynucleotides (PS-ODNs). PS-ODNs differ from natural DNA in that one of the nonbridging oxygen atoms in the phosphodiester linkage is substituted with sulfur. PS-ODNs are commercially available and easily synthesized, support RNase H activity, exhibit acceptable pharmacokinetics for systemic and local delivery, and have not exhibited major toxicities with use in humans (Glover et al., 1997; Crooke, 1998; Nemunaitis et al., 1999; Stevenson et al., 1999; Cunningham et al., 2000; Yuen et al., 2000). Significant resources have been applied to identify chemical modifications to further improve upon the properties of PS-ODNs. The primary objectives of this medicinal chemistry effort are to increase potency, decrease toxicity, enhance pharmacokinetics, and decrease cost of treatment. Modifications in the ribofuranosyl moiety backbone of the oligonucleotide have provided substantial improvements in oligonucleotide drug properties. In particular, 2 -O-(2-methoxyethyl) (2 -MOE) modifications have greatly increased binding affinity to the target mRNA, improved nuclease resistance (Cook, 1998), altered pharmacokinetics (Bennett et al., 2000; Geary et al., 2001a), and shown potentially improved safety profiles (Henry et al., 2001). It is well known that oligonucleotides that are uniformly modified with 2 -O-modifications do not support an RNase H mechanism of target RNA hydrolysis (Inoue et al., 1987). Since RNase H is an important terminating mechanism for antisense compounds, this has led to the development of a chimeric oligonucleotide strategy. One such chimeric strategy uses 2 -O-(2-methoxyethyl) modifications on the 3 and 5 -ends, and a “gapped” region remains in the center with a contiguous sequence of 2 -deoxy phosphorothioate nucleotides (Inoue et al., 1987; Lamond and Sproat, 1993; Monia et al., 1993; Yu et al., 1996; Dean and Griffey, 1997). This approach has led to the development of potent, pharmacologically active, specific antisense oligonucleotides, one of which is ISIS 104838. ISIS 104838 is a 20-base hybrid 2 -O-(2-methoxyethyl)/2 -deoxy phosphorothioate antisense oligonucleotide that represents the first compound of this chemical class to be dosed in humans (Sewell et al., 2002). ISIS 104838 targets the human TNFmRNA. Murine-specific homologs of ISIS 104838, targeting murine TNFmRNA, have exhibited potent pharmacology in preclinical animal models for inflammatory disease including collagen-induced inflammatory arthritis (internal data, unpublished). The pharmacokinetics of ISIS 104838 have been characterized in mice, rats, dogs, and monkeys during preclinical development. A compilation of the results of these impor1 Abbreviations used are: PS-ODN, phosphorothioate oligodeoxynucleotide; HPLC, high-performance liquid chromatography; ELISA, enzyme-linked immunosorbent assay; i.j., intrajejunal; CGE, capillary gel electrophoresis; LOQ, limit of quantitation; LLOQ, lower LOQ; ES/MS, electrospray ionization-mass spectrometry; LSC, liquid scintillation counting; AUC, area under the plasma concentration curve; CL, clearance; AUMC, area under the first moment curve; 2 -MOE, 2 -O-(2-methoxyethyl). Address correspondence to: Dr. Richard S. Geary, Isis Pharmaceuticals, Inc., 2292 Faraday Avenue, Carlsbad, CA 92008. E-mail: [email protected] 0090-9556/03/3111-1419–1428$7.00 DRUG METABOLISM AND DISPOSITION Vol. 31, No. 11 Copyright © 2003 by The American Society for Pharmacology and Experimental Therapeutics 1179/1108034 DMD 31:1419–1428, 2003 Printed in U.S.A. 1419 at A PE T Jornals on O cber 9, 2017 dm d.aspurnals.org D ow nladed from