Safety, Tolerability and Pharmacokinetics of BIBN 4096 BS, the First Selective Small Molecule Calcitonin Gene-Related Peptide Receptor Antagonist, Following Single Intravenous Administration in Healthy Volunteers

Abstract

BIBN 4096 BS ([R-(R∗,S∗)]-N-[2-[[5-amino-1-[[4-(4-pyridinyl)-1-piperazinyl]carbonyl] pentyl]amino]-1-[(3,5-dibromo-4-hydroxyphenyl)methyl]-2-oxoethyl]-4-(1,4-dihydro-2-oxo-3(2H)-quinazolinyl)-,1-piperidinecarboxamide) is the first selective, highly potent, small molecule, nonpeptide calcitonin gene-related peptide (CGRP) receptor antagonist, which has been developed for the treatment of acute migraine. The objective of this study was to obtain information on the safety, tolerability and pharmacokinetics of BIBN 4096 BS following single intravenous administration of rising doses (0.1, 0.25, 0.5, 1, 2.5, 5 and 10 mg) in 55 healthy male and female volunteers. The study was of single-centre, double-blind (within dose levels), placebo-controlled, randomized, single rising dose design. Blood pressure, pulse rate, respiratory rate, ECG, laboratory tests and forearm blood flow did not reveal any clinically relevant, drug-induced changes. Sixteen adverse events (AEs) were reported by eight of 41 volunteers after BIBN 4096 BS compared to five AEs reported by four of 14 volunteers after placebo. Approximately two-thirds of all AEs related to active treatment occurred at the highest dose of 10 mg. At this dose level, all AEs were confined to the three BIBN 4096 BS-treated females, and consisted mainly of transient and mild paresthesias. Paresthesias were the single most frequent AE, whereas fatigue was the AE which occurred in the highest number of subjects. Only two AEs were of moderate intensity, all remaining AEs were of mild intensity. No serious AEs were reported. The local tolerability after intravenous administration was good. In summary, intravenously administered BIBN 4096 BS revealed a very favourable safety profile over the dose range tested in both genders. Generally well tolerated at all dose levels, it was of satisfactory tolerability in female subjects at the highest dose of 10 mg. The plasma concentration-time courses of BIBN 4096 BS showed multicompartmental disposition characteristics. Mean maximum concentration (Cmax) values appeared to be dose-proportional. Based on the results from the two high dose levels (5 and 10 mg) with sufficient individual subject data, BIBN 4096 BS exhibited a total plasma clearance (CL) of approximately 12 l/h and an apparent volume of distribution at steady state (Vss) of approximately 20 l, resulting in a terminal half-life (t1/2) of approximately 2.5 h. Inter-individual variability was moderate with a coefficient of variation of approximately 45% based on the area under the plasma concentration-time curve (AUC) values. The mean renal clearance (CLR) was approximately 2 l/h, suggesting that renal excretion plays only a minor role in the elimination of unchanged BIBN 4096 BS.