Pharmacokinetic Drug-Drug Interaction With Coadministration of Cannabidiol and Everolimus in a Phase 1 Healthy Volunteer Trial

When highly purified cannabidiol (CBD; Epidiolex) and the mammalian target of rapamycin inhibitor everolimus are used concomitantly in the treatment of tuberous sclerosis complex, there is evidence of a pharmacokinetic (PK) interaction, leading to increased everolimus systemic exposure. We evaluated the effect of steady-state CBD exposure following multiple clinically relevant CBD doses on everolimus PK in healthy adult participants in a single-center, fixed-sequence, open-label, phase 1 study. All participants received oral everolimus 5 mg on day 1, followed by a 7-day washout. On days 9-17, participants received CBD (100 mg/mL oral solution) at 12.5 mg/kg in the morning and evening. On the morning of day 13, participants also received a single dose of oral everolimus 5 mg. Medications were taken 30 or 45 minutes (morning or evening dose) after starting a standardized meal. Maximum concentration and area under the concentration-time curve (AUC) from time of dosing to the last measurable concentration and extrapolated to infinity, of everolimus in whole blood were estimated using noncompartmental analysis, with geometric mean ratios and 90% confidence intervals for the ratios of everolimus dosed with CBD to everolimus dosed alone. A single dose of everolimus 5 mg was well tolerated when administered with multiple doses of CBD. Log-transformed everolimus maximum concentration, AUC from time of dosing to the last measurable concentration, and AUC extrapolated to infinity values increased by ≈2.5-fold, and everolimus half-life remained largely unchanged in the presence of steady-state CBD relative to everolimus dosed alone. Everolimus blood concentration monitoring should be strongly advised with appropriate dose reduction when coadministered with CBD.

A Phase 1 Open-Label, Fixed-Sequence Pharmacokinetic Drug Interaction Trial to Investigate the Effect of Cannabidiol on the CYP1A2 Probe Caffeine in Healthy Subjects

This pharmacokinetic (PK) drug‐interaction trial investigated the effects of repeated dosing of a plant‐derived pharmaceutical formulation of highly purified cannabidiol (CBD; Epidiolex in the United States and Epidyolex in Europe; 100 mg/mL oral solution) on caffeine clearance via modulation of cytochrome P450 (CYP) 1A2 activity in healthy adults. In this phase 1 open‐label, fixed‐sequence trial, all subjects received a single 200 mg caffeine dose and placebo on day 1. Subjects then titrated CBD from 250 mg once daily to 750 mg twice daily between days 3 and 11 and took 750 mg CBD twice daily between days 12 and 27. On day 26, subjects received a single 200‐mg caffeine dose with their morning CBD dose. Plasma concentrations of caffeine and its CYP1A2‐mediated metabolite, paraxanthine, were determined on days 1 and 26 and PK parameters derived using noncompartmental analysis. Safety was monitored throughout. Sixteen subjects enrolled, and 9 completed treatment. When caffeine was administered with steady‐state CBD, caffeine exposure increased by 15% for C_max and 95% for AUC_0‐∞, t_max increased from 1.5 to 3.0 hours, and t_1/2 increased from 5.4 to 10.9 hours compared with caffeine administered with placebo. Under the same conditions, paraxanthine exposure decreased by 22% for C_max and increased by 18% for AUC_0‐∞, t_max increased from 8.0 to 14.0 hours, and t_1/2 increased from 7.2 to 13.7 hours. Overall, there were no unexpected adverse events; diarrhea was most common, and 6 subjects discontinued because of elevated liver transaminases. These data suggest that CBD is an inhibitor of CYP1A2.

Pyrido[3,4-d]pyrimidin-4(3H)-one metabolism mediated by aldehyde oxidase is blocked by C2-substitution

1. We have previously described C8-substituted pyrido[3,4-d]pyrimidin-4(3H)-one derivatives as cell permeable inhibitors of the KDM4 and KDM5 subfamilies of JmjC histone lysine demethylases. 2. Although exemplar compound 1 exhibited moderate clearance in mouse liver microsomes, it was highly cleared in vivo due to metabolism by aldehyde oxidase (AO). Similar human and mouse AO-mediated metabolism was observed with the pyrido[3,4-d]pyrimidin-4(3H)-one scaffold and other C8-substituted derivatives. 3. We identified the C2-position as the oxidation site by LC-MS and 1H-NMR and showed that C2-substituted derivatives are no longer AO substrates. 4. In addition to the experimental data, these observations are supported by molecular modelling studies in the human AO protein crystal structure.

8-Substituted Pyrido[3,4-d]pyrimidin-4(3H)-one Derivatives As Potent, Cell Permeable, KDM4 (JMJD2) and KDM5 (JARID1) Histone Lysine Demethylase Inhibitors

We report the discovery of N-substituted 4-(pyridin-2-yl)thiazole-2-amine derivatives and their subsequent optimization, guided by structure-based design, to give 8-(1H-pyrazol-3-yl)pyrido[3,4-d]pyrimidin-4(3H)-ones, a series of potent JmjC histone N-methyl lysine demethylase (KDM) inhibitors which bind to Fe(II) in the active site. Substitution from C4 of the pyrazole moiety allows access to the histone peptide substrate binding site; incorporation of a conformationally constrained 4-phenylpiperidine linker gives derivatives such as 54j and 54k which demonstrate equipotent activity versus the KDM4 (JMJD2) and KDM5 (JARID1) subfamily demethylases, selectivity over representative exemplars of the KDM2, KDM3, and KDM6 subfamilies, cellular permeability in the Caco-2 assay, and, for 54k, inhibition of H3K9Me3 and H3K4Me3 demethylation in a cell-based assay.

Discovery of Potent, Selective, and Orally Bioavailable Small-Molecule Modulators of the Mediator Complex-Associated Kinases CDK8 and CDK19

The Mediator complex-associated cyclin-dependent kinase CDK8 has been implicated in human disease, particularly in colorectal cancer where it has been reported as a putative oncogene. Here we report the discovery of 109 (CCT251921), a potent, selective, and orally bioavailable inhibitor of CDK8 with equipotent affinity for CDK19. We describe a structure-based design approach leading to the discovery of a 3,4,5-trisubstituted-2-aminopyridine series and present the application of physicochemical property analyses to successfully reduce in vivo metabolic clearance, minimize transporter-mediated biliary elimination while maintaining acceptable aqueous solubility. Compound 109 affords the optimal compromise of in vitro biochemical, pharmacokinetic, and physicochemical properties and is suitable for progression to animal models of cancer.

Discovery of potent, orally bioavailable, small-molecule inhibitors of WNT signaling from a cell-based pathway screen

WNT signaling is frequently deregulated in malignancy, particularly in colon cancer, and plays a key role in the generation and maintenance of cancer stem cells. We report the discovery and optimization of a 3,4,5-trisubstituted pyridine 9 using a high-throughput cell-based reporter assay of WNT pathway activity. We demonstrate a twisted conformation about the pyridine-piperidine bond of 9 by small-molecule X-ray crystallography. Medicinal chemistry optimization to maintain this twisted conformation, cognisant of physicochemical properties likely to maintain good cell permeability, led to 74 (CCT251545), a potent small-molecule inhibitor of WNT signaling with good oral pharmacokinetics. We demonstrate inhibition of WNT pathway activity in a solid human tumor xenograft model with evidence for tumor growth inhibition following oral dosing. This work provides a successful example of hypothesis-driven medicinal chemistry optimization from a singleton hit against a cell-based pathway assay without knowledge of the biochemical target.

Demonstration of ignition radiation temperatures in indirect-drive inertial confinement fusion hohlraums

We demonstrate the hohlraum radiation temperature and symmetry required for ignition-scale inertial confinement fusion capsule implosions. Cryogenic gas-filled hohlraums with 2.2 mm-diameter capsules are heated with unprecedented laser energies of 1.2 MJ delivered by 192 ultraviolet laser beams on the National Ignition Facility. Laser backscatter measurements show that these hohlraums absorb 87% to 91% of the incident laser power resulting in peak radiation temperatures of T(RAD)=300 eV and a symmetric implosion to a 100 μm diameter hot core.

Quantitative study of calcium uptake by tumorigenic bone (TE-85) and neuroblastoma x glioma (NG108-15) cells exposed to extremely-low-frequency (ELF) electric fields

To verify the effect of cell culture state on frequency dependent increase in proliferation as well as Ca2+ flux across the plasma membrane, tumorigenic bone (TE-85) and neuroblastoma x glioma (NG108-15) cells cultured in the presence of fetal bovine serum (FBS) were exposed to capacitively coupled electric (CCEF) fields in the extremely low frequency (ELF) range of 10 to 18 Hz. [3H]Thymidine incorporation and 45Ca2+ uptake were used as endpoints. TE-85 cells cultured in the presence of 10% FBS did not exhibit a frequency dependent increase in proliferation in contrast to previous studies under growth arrested culture conditions, in which the cells were deprived of FBS. However, both TE-85 and NG108-15 cells had an increase in 45Ca2+ uptake in response to a 16 Hz 18.3 mV/cm CCEF. Fura-2 digital imaging microscopy was used to verify addition of 0.5 mM La3+ and 0.5 mM ionomycin as negative and positive controls, respectively. Imaging microscopy data was combined with 45Ca2+ incorporation results to quantify free intracellular calcium ([Ca2+]i) increase in response to CCEF exposure. TE-85 [Ca2+]i increased from 140 to 189-210 nM where as NG108-15 [Ca2+]i increased from 67 to 189-210 nM. These results suggested that serum deprivation may be a requirement for a frequency dependent increase in proliferation in TE-85 cells but is not necessary for the electric field induced increase in 45Ca2+ uptake in both TE-85 and NG108 cells. The present study also represents the first demonstration of increased 45Ca2+ uptake by neuroblastoma and/or glioma cells in response to an electric field exposure.

The effects of different steroids on costal and epiphyseal cartilage of fetal and adult rats

The effects of different doses of various steroids on growth, and on costal and epiphyseal chondrocytes, have been studied in prenatal, immature, and adult Long-Evans rats using histochemical techniques, and both light and electron microscopy. Both prenatal and postnatal treatments have been employed. The steroids used were cortisone (CA), betamethasome (BM), and, in the prenatal group only, dexamethasone (DM). Body weight is reduced in all treated rats (except the low dose of CA) by day 17 of gestation, with greater weight reductions occurring in rats receiving the higher dose level of each steroid. In rats treated prenatally or neonatally, and sacrificed postnatally on days 39-43 or days 116-127, body weights, and tibial and tail lengths, are less than in correspondingly aged controls, thus showing a persistence of the effects of treatment. Costal and epiphyseal cartilages in prenatal rats show cellular, synthetic, and ultrastructural alterations induced by treatment with glucocorticoids but the responses are not necessarily comparable. Except for the low dose of DM, the higher doses of each steroid are more effective in inhibiting, or altering, growth and cellular differentiation in the developing fetuses. Surprisingly, a low dose of DM has a more devastating effect on the cells and extracellular matrix of both costal and epiphyseal cartilage, than do higher dose-levels of the various steroids. Low doses of CA and BM are also effective in inhibiting or altering growth and cellular differentiation, but their effectiveness is largely limited to 17 days of gestation. The order of effect of the various doses of the different steroids on fetal cartilage, listed in decreasing order of severity, is as follows: 0.12 DM, 0.24 DM, 0.42 BM, 50 CA, with 25 CA and 0.18 BM being approximately equal and only slightly different from control cartilages. The effect of prenatal or neonatal glucocorticoid treatment on chondrocytes is minimal in the 30-43 days, or 116-127 day, postnatal groups. In immature and adult rats, cortisone affects the chondrocytes more deleteriously than does betamethasone, and a 5.0 mg dose of CA seems to affect chondrocytes, body weight, and tibial and tail lengths more than 0.2 or 7.5 mg doses.