Proof of pharmacology of Org 48775-0, a p38 MAP kinase inhibitor, in healthy volunteers.

AIM: To investigate the safety, tolerability, pharmacokinetics and pharmacodynamics of the highly selective oral p38alpha/beta mitogen-activated protein (MAP) kinase inhibitor Org 48,775-0 in a first-in-human study. METHODS: In the single ascending dosing (SAD) study, an oral dose of Org 48,775-0 (0.3-600 mg) was evaluated in healthy males. In the multiple ascending dosing (MAD) study, levels of 30, 70 and 150 mg were dosed for six consecutive days, twice daily. Both studies were performed in a double-blind, randomized, placebo-controlled, cross-over fashion and evaluated pharmacokinetics, pharmacodynamics (ex vivo inhibition of lipopolysaccharide [LPS]-induced tumor necrosis factor (TNFα) release) and routine clinical and laboratory data. Pharmacokinetic and pharmacodynamic parameters of Org 48,775-0 were compared between healthy males and postmenopausal females, and the effect of a standardized fat meal was evaluated. RESULTS: All adverse events observed in the SAD (16; dizziness and headache, diarrhoea and catheter-related phlebitis) and MAD (43; mainly somnolence, dizziness, headache and nasopharyngitis) cohorts were mild, transient and completely reversible. Pharmacokinetics were linear up to single doses of 400 mg. Median Tmax ranged from 0.5 to 1.8 hours, geometric mean for T1/2 from 7.0 to 14.4 hours. Org 48,775-0 doses equal to and greater than 30 mg significantly inhibited LPS-induced TNFα release (42.3%; 95% CI = -65.2, -4.3) compared to placebo. In the MAD study, Org 48,775-0 treatment inhibited LPS-induced TNFα release during the entire steady-state period. Levels of inhibition amounted 30-75% for 30 mg, 53-80% for 70 mg and 77-92% for 150 mg Org 48,775-0. CONCLUSION: Org 48,775-0 has the capacity to significantly inhibit MAP kinase activity in humans without safety concerns.

Detection of colorectal polyps in humans using an intravenously administered fluorescent peptide targeted against c-Met.

Colon cancer prevention currently relies on colonoscopy using white light to detect and remove polyps, but small and flat polyps are difficult to detect and frequently missed when using this technique. Fluorescence colonoscopy combined with a fluorescent probe specific for a polyp biomarker may improve polyp detection. Here we describe GE-137, a water-soluble probe consisting of a 26-amino acid cyclic peptide that binds the human tyrosine kinase c-Met conjugated to a fluorescent cyanine dye. Intravenous administration of GE-137 leads to its accumulation specifically in c-Met-expressing tumors in mice, and it is safe and well tolerated in humans. Fluorescence colonoscopy in patients receiving intravenous GE-137 enabled visualization of all neoplastic polyps that were visible with white light (38), as well as an additional nine polyps that were not visible with white light. This first-in-human pilot study shows that molecular imaging using an intravenous fluorescent agent specific for c-Met is feasible and safe, and that it may enable the detection of polyps missed by other techniques.