Jeffery Stone

Publications (2)5.74 Total impact

• Article: Plasma and cerebrospinal fluid pharmacokinetics of depsipeptide (FR901228) in nonhuman primates.

  Stacey L Berg, Jeffery Stone, Jim J Xiao, Kenneth K Chan, Jed Nuchtern, Robert Dauser, Leticia McGuffey, Patrick Thompson, Susan M Blaney
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  ABSTRACT: Acetylation of histones by histone acetyl transferases (HATs) leads to transcriptional activation, while histone deacetylase (HDAC) activity leads to transcriptional repression. Abnormalities of histone acetylation are associated with the malignant phenotype. Depsipeptide (FR901228) inhibits HDAC and has shown anticancer activity in preclinical models. We studied the plasma and cerebrospinal fluid (CSF) pharmacokinetics of depsipeptide in a nonhuman primate model that is highly predictive of human CSF penetration. Depsipeptide was administered intravenously at a dose of 10 mg/m(2) over 4 h to three different animals. Serial blood samples were obtained from all animals and serial CSF samples were obtained from two animals. Plasma and CSF concentrations of depsipeptide were measured using liquid chromatography/tandem mass spectrometry. Concentration-versus-time data were modeled using model-independent and model-dependent methods. The peak plasma concentration (median+/-SD) was 245+/-50 n M and occurred within the first 2 h of the infusion. The terminal half-life was 205+/-315 min, the AUC extrapolated to infinity was 50+/-15 micro M.min, and the total body clearance was 350+/-65 ml/min/m(2). In the two animals that had CSF sampling performed, the CSF peak concentration was 3.6 n M in one animal and 2.3 n M in the other, and the CSF half-lives were 250 and 325 min. The CSF penetration of depsipeptide (AUC(CSF):AUC(plasma)) was 2% in each animal. Observed changes included anorexia, fatigue, elevation of creatine phosphokinase (CPK) enzyme levels (muscle fraction), and transient early leukopenia. All animals recovered without sequelae. Although the CSF exposure to depsipeptide after intravenous administration was only 2%, CSF concentrations approached the IC(50) of depsipeptide in vitro for some tumors. Systemic administration of this agent may be useful for the treatment of leptomeningeal tumors.
  Cancer Chemotherapy and Pharmacology 08/2004; 54(1):85-8. · 2.83 Impact Factor
• Article: Thrombin peptide Chrysalin stimulates healing of diabetic foot ulcers in a placebo-controlled phase I/II study.

  Caroline Fife, Jon T Mader, Jeffery Stone, Leon Brill, Kathleen Satterfield, Andrea Norfleet, Amber Zwernemann, James T Ryaby, Darrell H Carney
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  ABSTRACT: Thrombin and thrombin peptides play a role in initiating tissue repair. The potential safety and efficacy of TP508 (Chrysalin) treatment of diabetic foot ulcers was evaluated in a 60-subject, prospective, randomized, double-blind, placebo-controlled phase I/II clinical trial. Chrysalin in saline or saline alone was applied topically, twice weekly, to diabetic ulcers with standardized care and offloading. A dose-dependent effect was seen in the per-protocol population where 1 and 10 mug Chrysalin treatment resulted in 45 and 72% more subjects with complete healing than placebo treatment. Chrysalin treatment of foot ulcers more than doubled the incidence of complete healing (p<0.05), increased mean closure rate approximately 80% (p<0.05), and decreased the median time to 100% closure by approximately 40% (p<0.05). Chrysalin treatment of heel ulcers within this population resulted in mean closure rates 165% higher than placebos (p<0.02) and complete healing in 86% (6/7) of ulcers compared with 0% (0/5) of placebo ulcers (p<0.03). Local wound reactions and adverse events (AEs) were equal between groups with no reported drug-related changes in laboratory tests or serious AEs. These results indicate the potential safety and efficacy of Chrysalin for treatment of diabetic foot ulcers.
  Wound Repair and Regeneration 15(1):23-34. · 2.91 Impact Factor