Nonclinical Development of ANX005: A Humanized Anti-C1q Antibody for Treatment of Autoimmune and Neurodegenerative Diseases.

ANX005 is a humanized immunoglobulin G4 recombinant antibody against C1q that inhibits its function as the initiating molecule of the classical complement cascade. The safety and tolerability of ANX005 are currently being evaluated in a phase I trial in healthy volunteers ( www.clinicaltrials.gov Identifier: NCT03010046). Inhibition of C1q can be applied therapeutically in a broad spectrum of diseases, including acute antibody-mediated autoimmune disease, such as Guillain-Barré syndrome (GBS), and in chronic diseases of the central nervous system involving complement-mediated neurodegeneration, such as Alzheimer's disease (AD). To support the clinical development of ANX005, several studies were conducted to assess the pharmacology, pharmacokinetics, and potential toxicity of ANX005. ANX-M1, the murine precursor of ANX005, functionally inhibits the classical complement cascade both in vitro and in vivo, to protect against disease pathology in mouse models of GBS and AD. Toxicology studies with ANX005, itself, showed that intravenous administration once weekly for 4 weeks was well tolerated in rats and monkeys, with no treatment-related adverse findings. Serum levels of ANX005 in monkeys correlate with a reduction in free C1q levels both in the serum and in the cerebrospinal fluid. In summary, ANX005 has shown proof of concept in in vitro and in vivo nonclinical pharmacology models, with no toxicity in the 4-week repeat-dose studies in rats and monkeys. The no observed adverse effect level was 200 mg/kg/dose, which is 200-fold higher than the first-in-human starting dose of 1 mg/kg in healthy volunteers.

Mechanisms underlying benign and reversible unconjugated hyperbilirubinemia observed with faldaprevir administration in hepatitis C virus patients.

Faldaprevir, an investigational agent for hepatitis C virus treatment, is well tolerated but associated with rapidly reversible, dose-dependent, clinically benign, unconjugated hyperbilirubinemia. Multidisciplinary preclinical and clinical studies were used to characterize mechanisms underlying this hyperbilirubinemia. In vitro, faldaprevir inhibited key processes involved in bilirubin clearance: UDP glucuronosyltransferase (UGT) 1A1 (UGT1A1) (IC50 0.45 µM), which conjugates bilirubin, and hepatic uptake and efflux transporters, organic anion-transporting polypeptide (OATP) 1B1 (IC50 0.57 µM), OATP1B3 (IC50 0.18 µM), and multidrug resistance-associated protein (MRP) 2 (IC50 6.2 µM), which transport bilirubin and its conjugates. In rat and human hepatocytes, uptake and biliary excretion of [(3)H]bilirubin and/or its glucuronides decreased on coincubation with faldaprevir. In monkeys, faldaprevir (≥20 mg/kg per day) caused reversible unconjugated hyperbilirubinemia, without hemolysis or hepatotoxicity. In clinical studies, faldaprevir-mediated hyperbilirubinemia was predominantly unconjugated, and levels of unconjugated bilirubin correlated with the UGT1A1*28 genotype. The reversible and dose-dependent nature of the clinical hyperbilirubinemia was consistent with competitive inhibition of bilirubin clearance by faldaprevir, and was not associated with liver toxicity or other adverse events. Overall, the reversible, unconjugated hyperbilirubinemia associated with faldaprevir may predominantly result from inhibition of bilirubin conjugation by UGT1A1, with inhibition of hepatic uptake of bilirubin also potentially playing a role. Since OATP1B1/1B3 are known to be involved in hepatic uptake of circulating bilirubin glucuronides, inhibition of OATP1B1/1B3 and MRP2 may underlie isolated increases in conjugated bilirubin. As such, faldaprevir-mediated hyperbilirubinemia is not associated with any liver injury or toxicity, and is considered to result from decreased bilirubin elimination due to a drug-bilirubin interaction.

Pharmacokinetic and Target Engagement Measures of ANX007, an Anti-C1q Antibody Fragment, Following Intravitreal Administration in Nonhuman Primates.

Purpose: C1q and the classical complement cascade are key regulators of synaptic pruning, and their aberrant activation has been implicated in neurodegenerative ophthalmic diseases including geographic atrophy and glaucoma. The antigen-binding fragment antibody ANX007 specifically recognizes globular head groups of C1q to block substrate binding and functionally inhibit classical complement cascade activation. ANX007 was assessed in nonclinical studies of biodistribution and C1q target engagement in the eye following intravitreal (IVT) administration in cynomolgus monkeys. Methods: Female juvenile cynomolgus monkeys (n = 12) received a single bilateral dose of 1 or 5 mg ANX007/eye, with vitreous and non-perfused tissue samples collected approximately 4 weeks later. In a separate study, male (n = 6/5) and female (n = 6/5) animals received repeat bilateral dosing of 1, 2.5, or 5 mg ANX007/eye on days 1 and 29, with aqueous and vitreous collections on day 44 or day 59. Tissues from the 5 mg/eye repeat-dose group were perfused, and retina, choroid, and optic nerve samples were collected approximately 2 and 4 weeks post-last dose. Results: Following a single dose of ANX007, vitreous levels of free drug were measurable through 4 weeks at both the 1 and 5 mg dose levels, with approximately 3-day half-life. With repeat dose of 5 mg/eye, free-ANX007 was measurable 4 weeks post-last dose in perfused retina and choroid and up to approximately 2 weeks post-last dose in optic nerve. There was a strong correlation between C1q target engagement and free drug levels in aqueous and vitreous humors and retinal tissue. Conclusions: Following IVT administration, ANX007 distributes to sites within the retina that are relevant to neurodegenerative ophthalmic disease with clear evidence of C1q target engagement. Based on its mechanism of action inhibiting C1q and its downstream activity, ANX007 is predicted to mitigate tissue damage driven by classical complement activation in the retina. These data support further clinical evaluation of ANX007.

Pharmacokinetics and local tissue response to local instillation of vocacapsaicin, a novel capsaicin prodrug, in rat and rabbit osteotomy models.

Vocacapsaicin is a novel prodrug of trans-capsaicin (trans-8-methyl-N-vanillyl-6-nonenamide) being developed as a nonopioid, long-lasting, site-specific treatment for postsurgical pain management. The objective of these studies was to examine the safety and tolerability of vocacapsaicin in an osteotomy model in two animal species and to evaluate bone healing parameters. Rats undergoing unilateral femoral osteotomy received a single perioperative administration (by instillation) of vocacapsaicin (vehicle, 0.15, 0.3, and 0.6 mg/kg). Rabbits undergoing unilateral ulnar osteotomy received a single perioperative administration (by infiltration and instillation) of vocacapsaicin (vehicle, 0.256 and 0.52 mg) alone or in combination with 0.5% ropivacaine. Clinical signs, body weights, food consumption, radiography, histopathologic examinations, ex vivo bone mineral density measurements (rats only), and biomechanical testing were evaluated at 4 and 8 weeks in rats and at 2 and 10 weeks in rabbits. Plasma samples were also collected in rabbits. There were no vocacapsaicin-related effects on mortality, clinical observations, body weight, or food consumption in either species. Systemic exposure to vocacapsaicin and its metabolites, including capsaicin, was transient. In rats, vocacapsaicin was devoid of deleterious effects on bone healing parameters, and there was a trend for enhanced bone healing in rats treated with the mid-dose. In rabbits, vocacapsaicin administered alone or in combination with ropivacaine did not adversely affect bone healing parameters. In conclusion, a single perioperative administration of vocacapsaicin in unilateral osteotomy models was well tolerated, locally and systemically, supporting its continued development as a novel, nonopioid treatment for postsurgical pain management.

Digoxin is not a substrate for organic anion-transporting polypeptide transporters OATP1A2, OATP1B1, OATP1B3, and OATP2B1 but is a substrate for a sodium-dependent transporter expressed in HEK293 cells.

Digoxin, an orally administered cardiac glycoside cardiovascular drug, has a narrow therapeutic window. Circulating digoxin levels (maximal concentration of ∼1.5 ng/ml) require careful monitoring, and the potential for drug-drug interactions (DDI) is a concern. Increases in digoxin plasma exposure caused by inhibition of P-glycoprotein (P-gp) have been reported. Digoxin has also been described as a substrate of various organic anion-transporting polypeptide (OATP) transporters, posing a risk that inhibition of OATPs may result in a clinically relevant DDI similar to what has been observed for P-gp. Although studies in rats have shown that Oatps contribute to the disposition of digoxin, the role of OATPs in the disposition of digoxin in humans has not been clearly defined. Using two methods, Boehringer Ingelheim, GlaxoSmithKline, Pfizer, and Solvo observed that digoxin is not a substrate of OATP1A2, OATP1B1, OATP1B3, and OATP2B1. However, digoxin inhibited the uptake of probe substrates of OATP1B1 (IC(50) of 47 µM), OATP1B3 (IC(50) > 8.1 µM), and OATP2B1 (IC(50) > 300 µM), but not OATP1A2 in transfected cell lines. It is interesting to note that digoxin is a substrate of a sodium-dependent transporter endogenously expressed in HEK293 cells because uptake of digoxin was significantly greater in cells incubated with sodium-fortified media compared with incubations conducted in media in which sodium was absent. Thus, although digoxin is not a substrate for the human OATP transporters evaluated in this study, in addition to P-gp-mediated efflux, its uptake and pharmacokinetic disposition may be partially facilitated by a sodium-dependent transporter.

Biomarkers for nonclinical infusion reactions in marketed biotherapeutics and considerations for study design.

The observation of an infusion reaction (IR) in a nonclinical study can cause concern among investigators and regulators in the development of biotherapeutics. Biomarkers can be informative to determine whether the reactions are immune-mediated or test-article related and if there is a potential risk to human subjects. IRs encompass a broad range of adverse events with a variety of triggers; the focus of this paper is IRs due to cytokine release syndrome or immune complex formation and the associated biomarkers. Such reactions generally do not preclude clinical development or marketing approval, because it is widely accepted that immune-mediated reactions in nonclinical species are not predictive of human outcomes. Several US approved products (from 2004 to 2016) have documented IRs in nonclinical species. This review article discusses recent examples, the biomarkers evaluated, and implications for study design and conduct.

Differential selectivity of efflux transporter inhibitors in Caco-2 and MDCK-MDR1 monolayers: a strategy to assess the interaction of a new chemical entity with P-gp, BCRP, and MRP2.

Determining the interaction of a molecule with membrane transporters is challenging because of overlapping substrate and inhibitor specificities and coexpression of multiple transporters. Caco-2 and MDCK-MDR1 cells were used to evaluate the selectivity of zosuquidar (LY335979), fumitremorgin C (FTC), and MK571 as inhibitors of P-glycoprotein (P-gp), breast cancer resistance protein (BCRP), and multidrug resistance-associated protein 2 (MRP2), respectively. Although these compounds are commonly used as transporter inhibitors, the concentrations at which they selectively inhibit P-gp, BCRP, and MRP2 have not been definitively assessed. In Caco-2 cells, which express P-gp, BCRP, and MRP2, FTC (1 µM) selectively inhibited the efflux of BCRP substrates estrone-3-sulfate and genistein; however, at 10 µM, FTC partially inhibited the efflux of P-gp substrates paclitaxel and digoxin. MK571 (50 µM), commonly used to inhibit MRP2, inhibited the efflux of P-gp and BCRP probe substrates in Caco-2 cells. In MDCK-MDR1 cells, which express human P-gp but not BCRP or MRP2, MK571 (50 µM) and FTC (10 µM) did not inhibit paclitaxel and digoxin efflux. Using Caco-2 cell monolayers, selected probe substrates, and optimized concentrations of LY335979 (3 µM) and FTC (1 µM), we propose a strategy to evaluate the interaction of a molecule with P-gp, BCRP, and MRP2.