We aim to establish an in vivo preclinical model to enable simultaneous assessment of inhibition potential of an investigational drug on clinically relevant drug transporters, organic anion-transporting polypeptide (OATP)1B, breast cancer resistance protein (BCRP), P-glycoprotein (P-gp), and organic anion transporter (OAT)3. Pharmacokinetics of substrate cocktail consisting of pitavastatin (OATP1B substrate), rosuvastatin (OATP1B/BCRP/OAT3), sulfasalazine (BCRP), and talinolol (P-gp) were obtained in cynomolgus monkey-alone or in combination with transporter inhibitors. Single-dose rifampicin (30 mg/kg) significantly ( < 0.01) increased the plasma exposure of all four drugs, with a marked effect on pitavastatin and rosuvastatin [area under the plasma concentration-time curve (AUC) ratio ∼21-39]. Elacridar, BCRP/P-gp inhibitor, increased the AUC of sulfasalazine, talinolol, as well as rosuvastatin and pitavastatin. An OAT1/3 inhibitor (probenecid) significantly ( < 0.05) impacted the renal clearance of rosuvastatin (∼8-fold). In vitro, rifampicin (10 M) inhibited uptake of pitavastatin, rosuvastatin, and sulfasalazine by monkey and human primary hepatocytes. Transport studies using membrane vesicles suggested that all probe substrates, except talinolol, are transported by cynoBCRP, whereas talinolol is a cynoP-gp substrate. Elacridar and rifampicin inhibited both cynoBCRP and cynoP-gp in vitro, indicating potential for in vivo intestinal efflux inhibition. In conclusion, a probe substrate cocktail was validated to simultaneously evaluate perpetrator impact on multiple clinically relevant transporters using the cynomolgus monkey. The results support the use of the cynomolgus monkey as a model that could enable drug-drug interaction risk assessment, before advancing a new molecular entity into clinical development, as well as providing mechanistic insights on transporter-mediated interactions.

Six BAs are quantified in human plasma using a multiplexed high-resolution mass spectrometry method. Glycodeoxycholic acid 3-sulfate and glycodeoxycholic acid 3-O-β-glucuronide are proposed as potential biomarkers based on observed four- to fivefold increase in plasma AUC (vs placebo), following administration of a compound known to present as an OATP1B1/3 inhibitor in vitro.

Cognitive decline and psychosis have been hypothesized to be mediated by N-methyl-d-aspartate receptor (NMDAR) hypofunction. Consistent with this hypothesis, chronic treatment with d-alanine, a coagonist at the glycine site of the NMDAR, leads to an improvement of positive and cognitive symptoms in schizophrenic patients. d-alanine is oxidized by d-amino acid oxidase (DAAO); thus, an inhibitor of DAAO would be expected to enhance d-alanine levels and likewise lead to desirable clinical outcomes. Sodium benzoate, on the basis of d-amino acid inhibition, was observed to display beneficial clinical effects in schizophrenic and Alzheimer's patients. However, in the clinical pilot studies using sodium benzoate, d-amino acids were not quantified to verify that sodium benzoate's efficacy was mediated through DAAO inhibition. In this study, d-alanine content was monitored in cerebral spinal fluid (CSF) of dogs treated with daily injections of d-alanine (30 mg/kg) alone and in combination with sodium benzoate (30 mg/kg) for seven consecutive days. We reasoned that the cerebral spinal fluid d-alanine quantity is reflective of the brain d-alanine levels and it would increase as a consequence of DAAO inhibition with sodium benzoate. We found that d-alanine treatment lead to maximal concentration of 7.51 μM CSF d-alanine level; however, coadministration of sodium benzoate and d-alanine did not change CSF d-alanine level beyond that of d-alanine treatment alone. As a consequence, we conclude that clinical efficacy associated with chronic administration of sodium benzoate in schizophrenic and Alzheimer's patients is likely not mediated through inhibition of DAAO.

Platinum-based chemotherapy is associated with nausea/emesis, anorexia and weight loss which reduce patient quality of life and limit treatment adherence potentially leading to poor treatment outcomes. Cisplatin increases circulating growth differentiation factor 15 (GDF-15), a cytokine that induces conditioned taste aversion, anorexia and weight loss in preclinical models. GDF-15 signals through the hindbrain receptor glial cell-derived neurotrophic factor receptor alpha-like (GFRAL). Cisplatin-induced anorexia/weight loss was attenuated in a GFRAL knockout mouse; therefore, we examined whether GDF-15 inhibition can prevent platinum-based chemotherapy-induced emesis, anorexia and weight loss, and also increase survival using mouse and/or nonhuman primate models. In cancer patients, platinum treatment increased circulating GDF-15 in non small cell lung carcinoma, colorectal, and ovarian cancer (~1.5 fold) compared to those receiving a non-platinum-based therapy. Furthermore, cisplatin, oxaliplatin and carboplatin administered individually all increased circulating GDF-15 in wildtype mice (≥ 5 fold) and induced anorexia, skeletal muscle wasting, and weight loss. GDF-15 mRNA was increased in kidney, liver, brain and white adipose tissue. These effects were prevented in GDF-15 knockout mice, however only a partial blockade was observed in the carboplatin group. In nonhuman primates, cisplatin treatment for 5 days (96% of the daily recommended clinical dose) also increased circulating GDF-15 (&gt; 5 fold), and induced anorexia and emesis. Treatment with the anti-GDF-15 monoclonal antibody (mAB1) resulted in no detectable circulating levels of free GDF-15, and attenuated both cisplatin-induced anorexia and emesis. Furthermore, in a mouse cachectic tumor model (subcutaneous implantation of tumor tissue derived from human non-small cell lung carcinoma adenocarcinoma), cisplatin treatment inhibited tumor growth; however, GDF-15 levels were still elevated and additional weight loss occurred compared to vehicle control. When mAB1 was given in combination with cisplatin, weight loss was reversed and tumor growth inhibition was maintained, resulting in greater survival compared to cisplatin alone. Taken together, these data support the notion that GDF-15 inhibition with mAB1 holds the potential as an effective therapeutic approach to alleviate GDF-15 mediated emesis, anorexia and weight loss with the aim to enable optimal cancer treatment as well as to improve patient quality of life and potentially survival. Citation Format: Danna M. Breen, Kevin Beaumont, Donald Bennett, Julia Brosnan, Roberto Calle, Jeffrey R. Chabot, Susie Collins, Teresa Cunio, Ryan M. Esquejo, Stephanie Joaquim, Alison Joyce, Hanna Kim, Laura Lin, Betty Pettersen, Shuxi Qiao, Michelle Rossulek, Brendan Tierney, Karen M. Walters, Gregory Weber, Zhidan Wu, Bei B. Zhang, Morris J. Birnbaum. Growth differentiation factor 15 (GDF-15) inhibition attenuates platinum-based chemotherapy-induced emesis, anorexia and weight loss and increases survival [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3056.