Baricitinib in adult patients with moderate-to-severe atopic dermatitis: A phase 2 parallel, double-blinded, randomized placebo-controlled multiple-dose study.

BACKGROUND: Baricitinib, an oral selective inhibitor of Janus kinase 1 and Janus kinase 2, modulates proinflammatory cytokine signaling. OBJECTIVES: The efficacy and safety of baricitinib were evaluated in patients with moderate-to-severe atopic dermatitis (AD). METHODS: In this phase 2, randomized, double-blind, placebo-controlled study, 124 patients with moderate-to-severe AD applied topical corticosteroids (TCSs) for 4 weeks before randomization to once-daily placebo, 2 mg of baricitinib, or 4 mg of baricitinib for 16 weeks. Use of TCSs was permitted during the study. The primary outcome was the proportion of patients achieving at least a 50% reduction in the Eczema Area and Severity Index (EASI-50) compared with placebo. RESULTS: Significantly more patients who received baricitinib, 4 mg, achieved EASI-50 than did patients receiving placebo (61% vs 37% [P = .027]) at 16 weeks. The difference between the proportion of patients receiving baricitinib, 2 or 4 mg, who achieved EASI-50 and the proportion of patients receiving placebo and achieving EASI-50 was significant as early as week 4. Baricitinib also improved pruritus and sleep loss. Treatment-emergent adverse events were reported in 24 of the patients receiving placebo (49%), 17 of those receiving 2 mg of baricitinib (46%), and 27 of those receiving 4 mg of baricitinib (71%). LIMITATIONS: A TCS standardization period before randomization reduced disease severity, limiting the ability to compare results with those of baricitinib monotherapy. Longer studies are required to confirm baricitinib's efficacy and safety in patients with AD. CONCLUSIONS: Baricitinib used with TCSs reduced inflammation and pruritus in patients with moderate-to-severe AD.

TRPA1 Antagonist LY3526318 Inhibits the Cinnamaldehyde-Evoked Dermal Blood Flow Increase: Translational Proof of Pharmacology.

Transient receptor potential Ankyrin 1 (TRPA1) is an ion channel expressed by sensory neurons, where it mediates pain signaling. Consequently, it has emerged as a promising target for novel analgesics, yet, to date, no TRPA1 antagonists have been approved for clinical use. In the present translational study, we utilized dermal blood flow changes evoked by TRPA1 agonist cinnamaldehyde as a target engagement biomarker to investigate the in vivo pharmacology of LY3526318, a novel TRPA1 antagonist. In rats, LY3526318 (1, 3, and 10 mg/kg, p.o.) dose-dependently reduced the cutaneous vasodilation typically observed following topical application of 10% v/v cinnamaldehyde. The inhibition was significant at the site of cinnamaldehyde application and also when including an adjacent area of skin. Similarly, in a cohort of 16 healthy human volunteers, LY3526318 administration (10, 30, and 100 mg, p.o.) dose-dependently reduced the elevated blood flow surrounding the site of 10% v/v cinnamaldehyde application, with a trend toward inhibition at the site of application. Comparisons between both species reveal that the effects of LY3526318 on the cinnamaldehyde-induced dermal blood flow are greater in rats relative to humans, even when adjusting for cross-species differences in potency of the compound at TRPA1. Exposure-response relationships suggest that a greater magnitude response may be observed in humans if higher antagonist concentrations could be achieved. Taken together, these results demonstrate that cinnamaldehyde-evoked changes in dermal blood flow can be utilized as a target engagement biomarker for TRPA1 activity and that LY3526318 antagonizes the ion channel both in rats and humans.

The fate of 4-hydroxycarbazole metabolite: metabolism and carcinogenicity assessment of a ß-adrenergic receptor modulator containing carbazole structure.

LY377604 has a potential to form 4-hydroxycarbazole, which was reported in the literature as a mutagen. This safety concern led to our investigation of the metabolism and carcinogenicity of LY377604. In in vitro studies with LY377604, 4-hydroxycarbazole was detected in the presence of liver microsomes prepared from different species. When incubated with liver slices, only the conjugate of 4-hydroxycarbazole was detected. Subsequent in vivo radio-labelled studies were conducted to characterise the formation of 4-hydroxycarbazole from LY377604. Free 4-hydroxycarbazole was not detected in vivo, but the O-glucuronide conjugate was identified as a minor metabolite in urine samples, representing 0.2% and 0.9% of the radioactive dose in rats and monkeys. The low level of circulating 4-hydroxycarbazole glucuronide conjugate was also detected in plasma. LY377604 was negative in all genetic toxicology assays and was not associated with tumour induction in a 6-month carcinogenicity study using RasH2+/- mouse model. The exposure to free 4-hydroxycarbazole was not measurable after one dose and was about 0.1%-0.2% of the parent exposure at the end of the 6-month study. These data suggested that 4-hydroxycarbazole was formed as a minor metabolite in vivo, but it was primarily conjugated and excreted in urine as the glucuronide conjugate. The absence of tumours in the carcinogenicity study combined with the exposure data suggested that the low level of free 4-hydroxycarbazole did not represent a carcinogenic risk.

Characterization of dark liver pigment observed in rats after subchronic dosing of the beta3-adrenergic receptor agonist LY368842.

Dark liver pigmentation was observed in F344 rats in a subchronic toxicology study after daily dosing of LY368842 glycolate. In addition, green-colored urine was observed in some animals. To identify the source of the pigment and its potential for toxic consequences, the liver pigment was isolated from the liver tissue of rats. The resulting material was a dark brown to black powder that was insoluble in water, organic solvents, or a tissue-solubilizing agent. Several techniques, such as chemical degradation, HPLC, tandem mass spectrometry (LC/MS/MS), (1)H NMR, and matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS), were employed to characterize the dark liver pigment. Following oxidative degradation of the isolated pigment, degradation products related to LY368842 were identified or tentatively identified using LC/MS/MS. Two degradation products had the same protonated molecular ion at m/z 505, which is 30 amu higher than that of LY368842. The major m/z 505 product has been identified as the indole-2,3-dione oxidative product based on (1)H NMR data and confirmed by an authentic standard. In addition, monohydroxylated product was also identified in the degradation mixture. These degradation products were consistent with the metabolites found in vivo in rats. MALDI-MS analyses of liver and urine pigment both identified a product with a protonated molecular ion at m/z 977, suggesting formation of indirubin-like and indigo-like pigments. The results obtained suggest that the oxidative metabolites of LY368842 played a key role in the formation of the liver and urine pigments.