Discovery and Model-Informed Drug Development of a Controlled-Release Formulation of Nonracemic Amisulpride that Reduces Plasma Exposure but Achieves Pharmacodynamic Bioequivalence in the Brain.

Nonracemic amisulpride (SEP-4199) is an investigational 85:15 ratio of aramisulpride to esamisulpride and currently in clinical trials for the treatment of bipolar depression. During testing of SEP-4199, a pharmacokinetic/pharmacodynamic (PK/PD) disconnect was discovered that prompted the development of a controlled-release (CR) formulation with improved therapeutic index for QT prolongation. Observations that supported the development of a CR formulation included (i) plasma concentrations of amisulpride enantiomers were cleared within 24-hours, but brain dopamine D2 receptor (D2R) occupancies, although achieving stable levels during this time, required 5 days to return to baseline; (ii) nonracemic amisulpride administered to non-human primates produced significantly greater D2R occupancies during a gradual 6-hour administration compared with a single bolus; (iii) concentration-occupancy curves were left-shifted in humans when nonracemic amisulpride was gradually administered over 3 and 6 hours compared with immediate delivery; (iv) CR solid oral dose formulations of nonracemic amisulpride were able to slow drug dissolution in vitro and reduce peak plasma exposures in vivo in human subjects. By mathematically solving for a drug distribution step into an effect compartment, and for binding to target receptors, the discovery of a novel PK/PD model (termed here as Distribution Model) accounted for hysteresis between plasma and brain, a lack of receptor saturation, and an absence of accumulation of drug occupancy with daily doses. The PK/PD disconnect solved by the Distribution Model provided model-informed drug development to continue in Phase III using the non-bioequivalent CR formulation with diminished QT prolongation as dose-equivalent to the immediate release (IR) formulation utilized in Phase II.

Development of a Once-Daily Modified-Release Formulation for the Short Half-Life RIPK1 Inhibitor GSK2982772 using DiffCORE Technology.

PURPOSE: GSK2982772 is a selective inhibitor of receptor-interacting protein kinase-1 (RIPK1) with a short 2- to 3-h half-life. In a previous modified-release (MR) study, a matrix monolithic formulation (80% GSK2982772 released over 12 h) provided a once-daily (QD) pharmacokinetic (PK) profile in the fasted state; however, it was susceptible to food effects. The current study evaluated the safety and PK of MR formulations using GSK proprietary DiffCORE™ technology. METHODS: Part A evaluated PK following single-dose (240 mg) fasted and fed (high-fat meal) administration of three DiffCORE MR formulations within pre-defined in vitro extremes of 80% GSK2982772 released over 12 h (MR-12 h) to 80% GSK2982772 released over 18 h (MR-18 h) versus an immediate-release formulation. Part B evaluated MR-16 h (120-960 mg) in different prandial states. RESULTS: Pharmacokinetic profiles for all MR formulations and doses tested in the fasted and fed states were consistent with QD dosing. CONCLUSIONS: The DiffCORE technology overcame the food effect vulnerability observed with the matrix monolithic formulation. The MR-16 h formulation was selected for further clinical development as a QD dosing regimen (NCT03649412 September 26, 2018).

Development of a Prototype, Once-Daily, Modified-Release Formulation for the Short Half-Life RIPK1 Inhibitor GSK2982772.

PURPOSE: GSK2982772 is a selective inhibitor of receptor-interacting protein kinase-1, with a 2-3 h half-life. This study evaluated if a once-daily modified-release formulation of GSK2982772 could be developed with no significant food effect. METHODS: Part A evaluated the pharmacokinetics of GSK2982772 following fasted single-dose (120 mg) administration of two matrix minitab formulations (MT-8 h and MT-12 h) vs 120 mg immediate release (IR) and MT-12 h with a high-fat meal. Part B evaluated once-daily MT-12 h for 3 days at three dose levels. Part C evaluated a matrix monolithic (MM-12 h) formulation at two dose levels in different prandial states. RESULTS: All modified-release formulations dosed in the fasted state reduced maximum plasma concentration (Cmax), delayed time to Cmax, and decreased area under the curve (AUC) vs IR. When MT-12 h or MM-12 h were co-administered with a meal (standard or high-fat) Cmax and AUC increased. Dosing MM-12 h 1 h before a standard or high-fat meal had minimal impact on exposure vs fasted. CONCLUSIONS: MT-12 h and MM-12 h provided a QD pharmacokinetic profile in the fasted state, however when MT-12 h was dosed with a high-fat meal a QD profile was not maintained. ( ClinicalTrials.gov Identifier: NCT03266172).

Safety, Pharmacokinetics, and Pharmacodynamics of ME-401, an Oral, Potent, and Selective Inhibitor of Phosphatidylinositol 3-Kinase P110δ, Following Single Ascending Dose Administration to Healthy Volunteers.

PURPOSE: ME-401 is a novel selective inhibitor of phosphatidylinositol 3 kinase p110δ, an enzyme often found overexpressed and overactive in B-cell malignancies. The current study was performed to assess the safety, tolerability, pharmacokinetics, and pharmacodynamics of single ascending oral doses of ME-401 in healthy volunteers. METHODS: This analysis was an open-label, nonrandomized study in healthy male volunteers. Three sequential groups were dosed. Each group received single doses of ME-401 on two occasions; the doses tested ranged from 10 to 150 mg. Blood was drawn at various time points to analyze plasma concentrations of ME-401 and inhibition of basophil activation, a marker of phosphatidylinositol 3 kinase p110δ inhibition. FINDINGS: Fifteen subjects received a single dose of ME-401 on two occasions. Three adverse events that were considered possibly related to the study drug were reported: one event of pain, one event of headache, and one event of upper abdominal pain. ME-401 exhibited dose proportionality up to 60 mg, and supra-proportional increases in exposure were observed above doses of 60 mg. In addition, there was a dose-proportional increase in the inhibition of basophil activation up to 60 mg. Mean t1/2 ranged from 9.36 to 29.23 hours across the dose range. A 60 mg dose of ME-401 approached 90% inhibition of basophil activation, and thereafter no further increase to the percent inhibition of basophil activation was observed for higher doses. Once-daily dosing of 60 mg ME-401 was forecasted to result in trough plasma levels exceeding the concentration needed for 90% inhibition of basophil activation. IMPLICATIONS: This first-in-human study showed that ME-401 was well tolerated after single doses up to 150 mg. Pharmacologic activity was confirmed after administration of single ascending oral doses of 10 to 150 mg. ME-401 60 mg, administered once daily, was selected as the starting dose for patient studies. ClinicalTrials.gov identifier: NCT02521389.

An Evaluation of the Pharmacodynamics, Safety, and Tolerability of the Potassium Binder RDX7675.

Hyperkalemia is common in patients with heart failure or chronic kidney disease, particularly those taking renin-angiotensin-aldosterone system inhibitors, and can cause arrhythmias and sudden cardiac death. The most widely used treatment, sodium polystyrene sulfonate (SPS), limits gastrointestinal potassium absorption, but has poor palatability. RDX7675 (RDX227675) is the calcium salt of a reengineered polystyrene sulfonate-based resin with improved palatability over SPS. The pharmacodynamic effects and safety of RDX7675 were assessed in a phase 1, single-center, randomized, active-controlled study. Healthy volunteers received nominal active doses of RDX7675 4.6 g twice a day (BID), 4.6 g 3 times a day (TID), 6.9 g BID, 13.7 g daily (QD), 9.2 g TID, or 13.7 g BID (n = 12 each), or equivalent doses of SPS (n = 3 each), for 4 days. RDX7675 dosing increased stool potassium excretion and decreased urinary potassium excretion from baseline. Stool potassium excretion increased by up to 1481 mg/day with RDX7675 (6.9 g BID), and urinary potassium excretion decreased by up to 939 mg/day (13.7 g BID). Similar levels of potassium excretion were observed using QD, BID, or TID dosing of a 13.7 g total daily RDX7675 dose. Few adverse events were reported. In conclusion, repeated oral dosing with RDX7675 over 4 days reduced potassium absorption in healthy volunteers; the results support QD dosing of RDX7675 in future clinical studies.

Assessment of Safety, Tolerability, Pharmacokinetics, and Pharmacological Effect of Orally Administered CORT125134: An Adaptive, Double-Blind, Randomized, Placebo-Controlled Phase 1 Clinical Study.

CORT125134 is an orally active, high-affinity, selective antagonist of the glucocorticoid receptor that is being developed for indications that may benefit from the modulation of cortisol activity. This first-in-human study was conducted to evaluate the dose-related safety, tolerability, pharmacokinetics and pharmacological effects of CORT125134 and its active metabolite CORT125201. Eighty-one healthy male or female subjects received a single dose of 5 to 500 mg CORT125134 or matching placebo across 9 cohorts; 1 cohort received 150 mg CORT125134 after a high-fat breakfast; and 46 subjects received 50 to 500 mg CORT125134 or matching placebo once daily for up to 14 days across 4 cohorts. CORT125134 was well tolerated at doses up to 250 mg per day for 14 days. CORT125134 was absorbed rapidly and eliminated with a mean half-life ranging from 11 to 19 hours. Steady state was achieved by day 7. Exposure increased in a greater than proportional manner, particularly at lower doses. Exposure to CORT125201 at steady state was less than 5% that of parent CORT125134. Evidence for the desired pharmacological effect (glucocorticoid receptor antagonism) was demonstrated by the ability of CORT125134 to prevent several effects of the glucocorticoid receptor agonist prednisone.

Palatability and physical properties of potassium-binding resin RDX7675: comparison with sodium polystyrene sulfonate.

BACKGROUND: Hyperkalemia is a potentially life-threatening condition that patients with heart failure or chronic kidney disease, especially those taking renin-angiotensin-aldosterone system inhibitors, are at high risk of developing. Sodium polystyrene sulfonate (SPS), a current treatment, binds potassium within the gastrointestinal tract to reduce potassium absorption. However, poor palatability limits its long-term use. RDX7675, a novel potassium binder in development for the treatment of hyperkalemia, is a calcium salt of a reengineered polystyrene sulfonate-based resin designed to have enhanced palatability. Here, the physical properties and palatability of RDX7675 and SPS are compared. METHODS: RDX7675 and SPS particle sizes were measured using wet dispersion laser diffraction. Palatability was assessed in a randomized, crossover, healthy volunteer study with two visits. At visit 1 (open label), volunteers evaluated high-viscosity, intermediate-viscosity, and water-reconstituted formulations of RDX7675 (all vanilla flavor), and an equivalent reconstituted SPS (Resonium A®). At visit 2 (single-blind), volunteers evaluated RDX7675 as a high-viscosity formulation in vanilla, citrus, and mint flavors, and as intermediate-viscosity, low-viscosity, and reconstituted formulations in citrus flavor. Volunteers used a "sip and spit" technique to rate overall acceptability and seven individual characteristics from 1 ("dislike everything") to 9 ("like extremely"). RESULTS: RDX7675 particles were smaller than SPS particles, with a narrower size range (RDX7675, 80%, 14-52 µm; SPS, 11.3-124.2 µm), and had a smooth, spherical shape, in contrast to the shard-like SPS particles. Reconstituted RDX7675 was considered superior to SPS for five of the seven palatability characteristics and for overall acceptability (median, visit 1: reconstituted RDX7675, 5.0; SPS, 4.0). High-viscosity vanilla was the most highly rated RDX7675 formulation (median overall acceptability, visit 2: 7.0). CONCLUSION: The smaller, more uniformly shaped, spherical particles of RDX7675 resulted in improved palatability over SPS when reconstituted in water. The overall results are promising for future patient acceptability of RDX7675 treatment.

Novel formulation of abiraterone acetate might allow significant dose reduction and eliminates substantial positive food effect.

PURPOSE: Zytiga (abiraterone acetate, AA) is known to exhibit very low bioavailability and a significant positive food effect in men. The unfavorable pharmacokinetic properties are attributed to the inadequate and variable dissolution of the compound. Using a continuous flow precipitation technology, a novel AA formulation has been developed with improved solubility and dissolution characteristics. The current study was performed to evaluate the pharmacokinetics and safety of this novel formulation in healthy volunteers. METHODS: The study was conducted in 11 healthy men aged 47-57 years. All subjects received 3 consecutive single doses of the novel formulation of AA (100 and 200 mg in the fasted state and 200 mg in the fed state). Data were compared with pharmacokinetic and safety data reported for 1000 mg Zytiga, the marketed drug. RESULTS: The novel formulation of AA allows rapid absorption of the compound with t max values within 1 hour. Based on AUC values, a ~250 mg dose of the novel formulation is predicted to give the same exposure as 1000 mg Zytiga in the fasted state. The significant positive food effect was also eliminated; actually, a slight, but statistically significant negative food effect was observed. Variability of exposure was significantly reduced when compared to Zytiga. AA administered in the novel formulation was well tolerated with no IMP-related safety AEs reported. CONCLUSION: The novel formulation might allow a 75% dose reduction with significant reduction of inter-individual variability. The negative food effect observed requires further investigations; however, elimination of the significant positive food effect could be adequate to negate the restriction of a food label.

Linking in Vitro Lipolysis and Microsomal Metabolism for the Quantitative Prediction of Oral Bioavailability of BCS II Drugs Administered in Lipidic Formulations.

Lipidic formulations (LFs) are increasingly utilized for the delivery of drugs that belong to class II of the Biopharmaceutics Classification System (BCS). The current work proposes, for the first time, the combination of in vitro lipolysis and microsomal metabolism studies for the quantitative prediction of human oral bioavailability of BCS II drugs administered in LFs. Marinol and Neoral were selected as model LFs, and their observed oral bioavailabilities (Fobserved) were obtained from published clinical studies in humans. Two separate lipolysis buffers, differing in the level of surfactant concentrations, were used for digestion of the LFs. The predicted fraction absorbed (Fabs) was calculated by measuring the drug concentration in the micellar phase after completion of the lipolysis process. To determine first-pass metabolism (Fg·Fh), drug depletion studies with human microsomes were performed. Clearance values were determined by applying the "in vitro half-life" approach. The estimated Fabs and Fg·Fh values were combined for the calculation of the predicted oral bioavailability (Fpredicted). Results showed that there was a strong correlation between Fobserved and Fpredicted values only when Fabs was calculated using a buffer with surfactant concentrations closer to physiological conditions. The general accuracy of the predicted values suggests that the novel in vitro lipolysis/metabolism approach could quantitatively predict the oral bioavailability of lipophilic drugs administered in LFs.

Chain length affects pancreatic lipase activity and the extent and pH-time profile of triglyceride lipolysis.

Triglycerides (TG) are one of the most common excipients used in oral lipid-based formulations. The chain length of the TG plays an important role in the oral bioavailability of the co-administered drug. Fatty acid (FA) chain-length specificity of porcine pancreatic lipase was studied by means of an in vitro lipolysis model under bio-relevant conditions at pH 6.80. In order to determine the total extent of lipolysis, back-titration experiments at pH 11.50 were performed. Results suggest that there is a specific chain length range (C2-C8) for which pancreatic lipase shows higher activity. This specificity could result from a combination of physicochemical properties of TGs, 2-monoglycerides (2-MGs) and FAs, namely the droplet size of the TGs, the solubility of 2-MGs within mixed micelles, and the relative stability of the FAs as leaving groups in the hydrolysis reaction. During experimentation, it was evident that an optimisation of lipolysis conditions was needed for tighter control over pH levels so as to better mimic in vivo conditions. 1M NaOH, 3.5 mL/min maximum dosing rate, and 3 µL/min minimum dosing rate were the optimised set of conditions that allowed better pH control, as well as the differentiation of the lipolysis of different lipid loads.

On the colonic bacterial metabolism of azo-bonded prodrugsof 5-aminosalicylic acid.

Azo-bonded prodrugs of 5-aminosalicylic acid (mesalazine)-sulfasalazine, balsalazide, and olsalazine, which are used in the treatment of ulcerative colitis, rely on colonic bacteria to cleave the azo bond and liberate the active drug in the large intestine. The aim of this study was to use an in vitro colonic simulator to determine the rates of metabolism of these three prodrugs in the presence of colonic bacteria, and to link the data to results obtained previously in humans. In individual fecal slurries prepared from five different donors, sulfasalazine degradation was rapid and virtually complete within 4 h, confirming the ubiquitous nature of azo-reduction between individuals. In pooled fecal slurry, the rate of degradation of sulfasalazine was faster (t1/2 , 32.8 min) than balsalazide (t1/2 , 80.9 min) and olsalazine (t1/2 , 145.1 min). These results are in agreement with data in humans, where it was found that sulfasalazine was more extensively metabolized on passage through the human colon than the other two drugs. These findings indicate that other than the azo bond itself, the broader chemical structure of the molecules play a role in the degradation of this class of compound, and highlight the utility of this in vitro model to evaluate the metabolism of drugs in the presence of colonic microbiota.

Digoxin net secretory transport in bronchial epithelial cell layers is not exclusively mediated by P-glycoprotein/MDR1.

The impact of P-glycoprotein (MDR1, ABCB1) on drug disposition in the lungs as well as its presence and activity in in vitro respiratory drug absorption models remain controversial to date. Hence, we characterised MDR1 expression and the bidirectional transport of the common MDR1 probe (3)H-digoxin in air-liquid interfaced (ALI) layers of normal human bronchial epithelial (NHBE) cells and of the Calu-3 bronchial epithelial cell line at different passage numbers. Madin-Darby Canine Kidney (MDCKII) cells transfected with the human MDR1 were used as positive controls. (3)H-digoxin efflux ratio (ER) was low and highly variable in NHBE layers. In contrast, ER=11.4 or 3.0 were measured in Calu-3 layers at a low or high passage number, respectively. These were, however, in contradiction with increased MDR1 protein levels observed upon passaging. Furthermore, ATP depletion and the two MDR1 inhibitory antibodies MRK16 and UIC2 had no or only a marginal impact on (3)H-digoxin net secretory transport in the cell line. Our data do not support an exclusive role of MDR1 in (3)H-digoxin apparent efflux in ALI Calu-3 layers and suggest the participation of an ATP-independent carrier. Identification of this transporter might provide a better understanding of drug distribution in the lungs.