Pharmacokinetics and Safety of Cilofexor and Firsocostat in Healthy Japanese and Non-Japanese Participants.

Cilofexor, an oral farnesoid X receptor agonist, and firsocostat, an oral, liver-targeted inhibitor of acetyl-coenzyme A carboxylase, are being investigated in combination with semaglutide for the treatment of metabolic dysfunction-associated steatohepatitis (previously known as nonalcoholic steatohepatitis; NCT04971785). The pharmacokinetics and safety profiles of cilofexor (100 mg) and firsocostat (20 mg) were separately investigated in two phase 1 studies, each of which included healthy Japanese participants (n = 20 in the cilofexor study and n = 21 in the firsocostat study) and non-Japanese participants (n = 20 in the cilofexor study and n = 21 in the firsocostat study). Intensive pharmacokinetic sampling was performed over 96 h following a single-dose administration of the study drug.

Pharmacokinetics, pharmacodynamics, and safety of GS-3583, a FLT3 agonist Fc fusion protein, from single-ascending-dose phase I study in healthy participants.

Conventional dendritic cells subtype 1 (cDC1) play a vital role in the priming and expansion of tumor-specific CD8+ T cells and their recruitment to tumor microenvironment. However, cDC1s are often underrepresented in the microenvironment. Systemic administration of Fms-like tyrosine kinase 3 ligand, a hematopoietic growth factor that binds to FLT3 on myeloid and lymphoid progenitor cells, leads to cDC1 expansion in the periphery and recruitment into the microenvironment.

Plasma Protein Binding Determination for Unstable Ester Prodrugs: Remdesivir and Tenofovir Alafenamide.

Remdesivir (RDV) and tenofovir alafenamide (TAF) are prodrugs designed to be converted to their respective active metabolites. Plasma protein binding (PPB) determination of these prodrugs is important for patients with possible alteration of free fraction of the drugs due to plasma protein changes in renal impairment, hepatic impairment, or pregnancy. However, the prodrugs' instability in human plasma presents a challenge for accurate PPB determination.

Organic Anion Transporting Polypeptide Inhibition Dramatically Increases Plasma Exposure but not Pharmacodynamic Effect nor Inferred Hepatic Intracellular Exposure of Firsocostat.

Firsocostat (FIR: previously GS-0976), a highly sensitive OATP substrate, reduces hepatic de novo lipogenesis (DNL) by inhibiting acetyl-CoA carboxylases (ACC). Measuring the pharmacodynamic (PD) efficacy of FIR on DNL provides a unique opportunity to determine optimal dosing strategies for liver-targeted OATP substrates in settings of altered OATP function. A randomized, four-way crossover drug-drug interaction study was conducted.

The Relative Bioavailability and Effects of Food and Acid-Reducing Agents on Filgotinib Tablets in Healthy Subjects.

Filgotinib is a potent, selective Janus kinase-1 inhibitor being developed to treat chronic inflammatory diseases. This phase 1 study in healthy subjects evaluated the relative bioavailability of filgotinib maleate tablets versus the reference tablet (filgotinib hydrochloride) and effects of food and acid-reducing agents (ARAs) on the pharmacokinetics of filgotinib and its major metabolite. Noncompartmental pharmacokinetic parameters of filgotinib and its major metabolite were compared between the 2 tablets at 100- and 200-mg doses and with or without food or ARAs.

Collagenase as an effective tool for drug quantitation in tissues.

Background: In early drug-discovery research, traditional techniques to analyze drug concentrations in tissues for bioanalytical needs include bead beaters and probe homogenization devices, but are not as effective for tough fibrous tissues. To prepare these tissues, the enzyme collagenase was used to digest the collagen fibers present in epithelial and connective tissue.

Results: The benefits of tissue homogenization using a bead beater following collagenase treatment of samples, as opposed to using bead beating alone, was investigated.

Measuring NAD(+) levels in mouse blood and tissue samples via a surrogate matrix approach using LC-MS/MS.

Background: NAD(+) is an endogenous analyte and is unstable during blood sample collection, both of which present obstacles for quantitation. Moreover, current procedures for NAD(+) sample collection require onsite treatment with strong acid to stabilize the NAD(+) in mouse blood cells.

Results: NAD(+) can be stabilized by addition of acid before the frozen mouse blood sample was thawed.