Reducing Adverse Effects During Drug Development: The Example of Lesogaberan and Paresthesia.

PURPOSE: Lesogaberan, a γ-aminobutyric acid (GABA)B receptor agonist, was developed for the treatment of gastroesophageal reflux disease in patients with a partial response to proton pump inhibitor therapy. A high prevalence of paresthesia was observed in healthy individuals after dosing with lesogaberan in early-phase clinical trials. The aim of this review was to gain further insight into paresthesia caused by lesogaberan by summarizing the relevant preclinical and clinical data. METHODS: This study was a narrative review of the literature and unpublished data. FINDINGS: The occurrence of paresthesia may depend on the route or rate of drug administration; several studies were conducted to test this hypothesis, and formulations were developed to minimize the occurrence of paresthesia. Phase I clinical studies showed that, in healthy individuals, paresthesia occurred soon after administration of lesogaberan in a dose-dependent manner regardless of the route of administration. The occurrence of paresthesia could be decreased by fractionating the dose or reducing the rate of administration. These findings suggest that the initial rate of absorption plays an important part in the development of paresthesia. Modified-release formulations minimize the occurrence of paresthesia while retaining the anti-reflux activity of the drug, as measured by esophageal pH and the number of transient lower esophageal sphincter relaxations. IMPLICATIONS: The development of lesogaberan was halted because the effect on gastroesophageal reflux disease symptoms observed in Phase II studies was not considered clinically meaningful in the target patient population. Nevertheless, it is an example of successful formulation development designed to minimize the occurrence of a compound's adverse effect while retaining its pharmacodynamic action.

Identification of the metabolites of lesogaberan using linear trap quadrupole orbitrap mass spectrometry and hydrophilic interaction liquid chromatography.

1. In this study, hydrophilic interaction liquid chromatography (HILIC), radiochemical activity monitoring and linear trap quadrupole orbitrap mass spectrometry (MS) and tandem mass spectrometry (MS/MS) were used to identify the metabolites of a highly polar novel γ-aminobutyric acid type-B receptor agonist, lesogaberan, in rats. 2. Urine was collected from three male Wistar rats for 24 h after dosing with (14)C-labelled lesogaberan (170 mg/kg, 10 MBq/kg); plasma samples were taken 2 and 24 h after dosing. Pooled samples were separated by HILIC and eluents were analysed by radiochemical activity monitoring, MS and MS/MS. 3. Only the parent compound was detected in plasma, but six metabolites (M1-M6) were detected in urine. Analysis of MS and MS/MS data and comparison with synthetic reference standards enabled the identification of the structure of each metabolite. M1 was identified as the N-acetylated species [(2R)-3-acetamido-2-fluoropropyl]-phosphinic acid, and M6 as [(2R)-3-amino-2-fluoropropyl]-phosphonic acid. Metabolites M2 and M5 were the alcohol and carboxylic acid species 3-hydroxypropyl-phosphinic acid and 3-hydroxyphosphonoyl-propanoic acid, respectively, both of which had lost the fluorine atom present in the parent compound. M3 was the corresponding carboxylic acid species retaining the fluorine atom, (2R)-2-fluoro-3-hydroxyphosphonoyl-propanoic acid. Finally M4 was identified as [(2R)-2-fluoro-3-guanidino-propyl]-phosphinic acid.