Importance of PLD2 in an IL-23 driven psoriasiform dermatitis model and potential link to human psoriasis.

Phospholipase D2 (PLD2), a major isoform of the PLD family, has been reported to regulate inflammatory responses. Thus far, the relevance of PLD2 in psoriasis, an inflammatory skin disease, has not been explored. In the current study, we examined PLD2 expression in the skin of psoriasis patients and the role of PLD2 in an interleukin (IL)-23-induced mouse model of psoriasiform dermatitis. Both in situ hybridization and bulk RNA sequencing showed PLD2 gene expression is significantly higher in lesional relative to non-lesional skin of psoriasis patients or the skin of healthy subjects. PLD2 expression is also enriched in residual lesions from patients on biologic therapies. Murine in vivo studies showed that PLD2 deficiency significantly reduced psoriasiform inflammation in IL-23-injected ears, as reflected by decreases in ear thickness, expression of defensin beta 4A and the S100 calcium binding protein A7A, macrophage infiltrate, and expression of CXCL10 and IL-6. However, the expression of type 17 cytokines, IL-17A and IL-17F, were not reduced. Dual knockout of PLD1 and PLD2 offered little additional protection compared to PLD2 knockout alone in the IL-23 model. In addition, pharmacological inhibition with a pan-PLD1/PLD2 inhibitor also suppressed IL-23-induced psoriasiform dermatitis. Bone-marrow-derived macrophages from wild type (WT) and PLD2 knockout (KO) mice exhibited little difference in viability and sensitivity to lipopolysaccharide and/or interferon gamma, or resiquimod (R848). PLD2 deficiency did not alter the differentiation and function of Th17 cells in an ex vivo study with splenocytes isolated from WT and PLD2 KO mice. Overall, these data suggest that PLD2 may play a role in the pathophysiology of psoriasis. Reducing macrophage infiltrate and cytokine/chemokine production might contribute to an anti-inflammatory effect observed in PLD2 knockout mice. Further studies are required to better understand the mechanisms by which PLD2 contributes to skin lesions in psoriasis patients and psoriasiform dermatitis models.

Rilzabrutinib, a reversible covalent Bruton's tyrosine kinase inhibitor: Absorption, metabolism, excretion, and absolute bioavailability in healthy participants.

This single-center, open-label, non-randomized, two-part, phase I study was conducted (1) to evaluate the absolute oral bioavailability of rilzabrutinib 400 mg tablet following an i.v. microtracer dose of ~100 µg [14C]-rilzabrutinib (~1 µCi) and single oral dose of 400 mg rilzabrutinib tablet (part 1), and (2) to characterize the absorption, metabolism, and excretion (AME) of 14C-radiolabeled rilzabrutinib following single oral dose (300 mg) of [14C]-rilzabrutinib (~1000 µCi; administered as a liquid) in healthy male participants (part 2). A total of 18 subjects were enrolled (n = 8 in part 1; n = 10 in part 2). The absolute bioavailability of 400 mg rilzabrutinib oral tablet was low (<5%). In part 1, rilzabrutinib was absorbed rapidly after single oral dose of rilzabrutinib 400 mg tablet with a median (range) time to maximum concentration (Tmax ) value of 2.03 h (1.83-2.50 h). The geometric mean (coefficient of variation) terminal half-life following the oral dose and i.v. microtracer dose of ~100 µg [14C]-rilzabrutinib, were 3.20 (51.0%) and 1.78 (37.6%) h, respectively. In part 2, rilzabrutinib was also absorbed rapidly following single oral dose of 300 mg [14C]-rilzabrutinib solution with a median (range) Tmax value of 1.00 h (1.00-2.00 h). The majority of total radioactivity was in the feces for both non-bile collection subjects (92.9%) and bile collection subjects (87.6%), and ~5% of radioactivity was recovered in urine after oral administration. Urinary excretion of unchanged rilzabrutinib was low (3.02%). The results of this study advance the understanding of the absolute bioavailability and AME of rilzabrutinib and can help inform its further investigation.

A thorough QTc study to evaluate the effects of oral rilzabrutinib administered alone and with ritonavir in healthy subjects.

This study aimed to define the clinically relevant supratherapeutic dose of rilzabrutinib, an oral Bruton tyrosine kinase (BTK) inhibitor, and evaluate potential effects of therapeutic and supratherapeutic exposures on cardiac repolarization in healthy subjects. This was a two-part phase I study (anzctr.org.au ACTRN12618001036202). Part A was a randomized, open-label, three-period, single-dose crossover study (n = 12) with rilzabrutinib 100 mg ± ritonavir 100 mg or rilzabrutinib 1200 mg. Part B was a randomized, double-blind, placebo-controlled, four-way, single-dose crossover study (n = 39) with matched placebo, rilzabrutinib 400 mg ± ritonavir 100 mg, or moxifloxacin (positive control). Primary objectives: part A - pharmacokinetics (PK) of rilzabrutinib ± ritonavir, safety, and optimal dose for Part B; Part B - effect of rilzabrutinib therapeutic and supratherapeutic concentration on electrocardiogram (ECG) parameters. ECGs and PK samples were serially recorded before and post-dose. In part A, rilzabrutinib 100 mg + ritonavir led to 17-fold area under the concentration-time curve (AUC0-∞ ) and 7-fold maximum plasma concentration (Cmax ) increases over rilzabrutinib alone. Rilzabrutinib 1200 mg was discontinued due to mild-to-moderate gastrointestinal intolerance. In Part B, rilzabrutinib 400 mg + ritonavir increased rilzabrutinib mean AUC0-∞ from 454 to 3800 ng h/mL and Cmax from 144 to 712 ng/mL. The concentration-QTc relationship was slightly negative, shallow (-0.01 ms/ng/mL [90% CI -0.016 to -0.001]), and an effect >10 ms on QTcF could be excluded within the observed range of plasma concentrations, up to 2500 ng/mL. Safety was similar to other studies of rilzabrutinib. In conclusion, rilzabrutinib, even at supratherapeutic doses, had no clinically relevant effects on ECG parameters, including the QTc interval.

Preclinical Mechanisms of Topical PRN473, a Bruton Tyrosine Kinase Inhibitor, in Immune-Mediated Skin Disease Models.

The expression of Bruton tyrosine kinase (BTK) in B cells and innate immune cells provides essential downstream signaling for BCR, Fc receptors, and other innate immune cell pathways. The topical covalent BTK inhibitor PRN473 has shown durable, reversible BTK occupancy with rapid on-rate and slow off-rate binding kinetics and long residence time, resulting in prolonged, localized efficacy with low systemic exposure in vivo. Mechanisms of PRN473 include inhibition of IgE (FcεR)-mediated activation of mast cells and basophils, IgG (FcγR)-mediated activation of monocytes, and neutrophil migration. In vivo, oral PRN473 was efficacious and well tolerated in the treatment of canine pemphigus foliaceus. In this study, we evaluated in vitro selectivity and functionality, in vivo skin Ab inflammatory responses, and systemic pharmacology with topically administered PRN473. Significant dose-dependent inhibition of IgG-mediated passive Arthus reaction in rats was observed with topical PRN473 and was maintained when given 16 h prior to challenge, reinforcing extended activity with once-daily administration. Similarly, topical PRN473 resulted in significant dose-dependent inhibition of the mouse passive cutaneous anaphylaxis IgE-mediated reaction. Multiday treatment with topical PRN473 in rodents resulted in low-to-no systemic accumulation, suggesting that efficacy was mainly due to localized exposure. Reduced skin Ab inflammatory activity was also confirmed with oral PRN473. These preclinical studies provide a strong biologic basis for targeting innate immune cell responses locally in the skin, with rapid onset of action following once-daily topical PRN473 administration and minimal systemic exposure. Dose-dependent inhibition in these preclinical models of immune-mediated skin diseases support future clinical studies.

Two-year outcomes of a pilot glaucoma suspect telemedicine monitoring program.

PURPOSE: The purpose of this study was to characterize a pilot program using e-health to monitor glaucoma suspects in a large integrated health system. METHODS: A retrospective chart review of patients enrolled in the first 2 years of a new glaucoma suspect telemedicine monitoring program was conducted. Patients were enrolled in the program after being diagnosed as glaucoma suspects in the regular clinic setting and were eligible for the program if they had better than 20/40 vision, intraocular pressure (IOP) <25 mmHg, a normal baseline visual field, and an optical coherence tomography (OCT) retinal nerve fiber layer (RNFL) without clear evidence of glaucomatous optic nerve damage. Patients were followed annually thereafter with measurements of vision, IOP, and OCT RNFL, which were reviewed at a centralized telemedicine reading center. Patients were retained within the program unless there was evidence of disease progression, in which case they were referred to an ophthalmologist for further evaluation. The first 100 patients received a survey assessing their satisfaction with the program after their first visit. The number of patients who adhered to follow-up recommendations, who were referred to an ophthalmologist for additional evaluation, and who began on IOP-lowering medications was evaluated. RESULTS: A total of 225 patients were enrolled in this program. Of eligible patients, 97.3% attended their 1-year follow-up visit and 92.5% attended their 2-year follow-up visit. Over the course of 2 years, five patients were referred for further clinic evaluation due to concern for progressive RNFL loss, of which two were started on IOP-lowering medications. No patients were referred to the clinic for vision loss or elevated IOP. In all, 87% of patients said that they would be extremely or quite likely to recommend the program to a friend. More than 80% of patients said that the program was extremely or very helpful, convenient, and professional. CONCLUSION: This novel telemedicine program for monitoring low-risk glaucoma suspects achieved high patient retention. Significant disease progression was rare with a few patients requiring referrals back to the clinic setting or initiation of IOP-lowering therapy. Telemedicine is a promising method to follow patients who are glaucoma suspects.

Comparing the relative benefits of grooming-contact and full-contact pairing for laboratory-housed adult female Macaca fascicularis.

Tactile social contact is the most effective form of environmental enrichment for promoting normal behavior in captive primates. For laboratory macaques housed indoors, pair housing is the most common method for socialization. Pairs can be housed either in full contact (FC), or in protected contact (PC). At Washington National Primate Research Center, PC is provided by grooming-contact (GC) cages whereby two partners are housed individually in adjacent cages with access to each other through widely spaced vertical bars. Grooming-contact has been used to accommodate research protocol restrictions and improve the likelihood of compatibility for various pairings, in part by enabling male-female pairs. This study compares the benefits between the two housing types by video recording 14 pairs of adult female Macaca fascicularis in four sequential housing phases following an ABBA design: baseline grooming-contact, full contact shortly after introduction, 1-month-later full contact, and after reversion to grooming-contact. Prior to this study, pairs had been housed compatibly in GC. Twelve of the 14 long-term pairs transitioned successfully to full contact and data presented exclude the two failed pairs. Allogrooming increased significantly when pairs first switched from GC to FC (P = 0.018), but the effect did not last through the on 1-month-later FC phase suggesting that the initial improvement in affiliative behavior was a transitory novelty response that did not persist. Self-grooming significantly decreased between the first GC and first FC phases (P = 0.016), likely due to redirected allogrooming. Non-contact affiliative behavior towards partner or other conspecifics in the room did not differ, nor did agonism towards partner or others in the room. Occurrence of abnormal, tension, manipulation, miscellaneous active, and inactive behaviors did not differ significantly across housing phases. Proximity measurements indicated that pairs were significantly out of arm's reach more often in protected contact than when in full contact (P ≤ 0.02). Proportion of time spent in physical contact significantly increased between the first GC and first FC phases (P = 0.002), but subsequently declined. For both FC phases, partners chose to spend about 50% of their time in the same cage. Few behavioral improvements were seen after pairs switched to full contact and no negative effects came of reversion to grooming contact. This study suggests that tactile contact provided through widely spaced bars (grooming-contact) is a viable alternative to full contact housing for adult female longtailed macaques. It provides a degree of social housing while allowing both partners choice and control, key concepts in contemporary animal welfare guidelines.

An interesting relationship between drug absorption and melting point.

The ability to predict the extent of passive intestinal drug absorption is very important for efficient lead candidate selection and development. Physicochemical-based absorption predictive models previously developed use solubility, partition coefficient and pK(a) as drug input parameters for intestinal absorption. Alternatively, this study looks at the relationship between melting point and passive transport for poorly soluble drugs. It is based entirely on the expression derived from the General Solubility Equation (GSE) that relates melting point to the product of intrinsic solubility and partition coefficient. Given that the melting point of a compound is one of the first and more reliable physical properties measured, it can be advantageously used as a guide in early drug discovery and development. This paper elucidates the interesting relationship between the melting point and dose to the fraction absorbed of poorly soluble drugs, i.e., class II and IV compounds in the Biopharmaceutics Classification System. The newly defined melting point based absorption potential (MPbAP) parameter is successful at distinguishing 90% of the 91 drugs considered being well absorbed (FA>0.5) or poorly absorbed. In general, lower melting compounds are more likely to be well absorbed than higher melting compounds for any given dose. The fraction absorbed for drugs with high melting temperatures is limited by the dose to a greater degree than it is for low melting compounds.

Predicting aqueous solubility: the role of crystallinity.

This paper revisits the role of crystallinity in predicting the aqueous solubility of a wide variety of organic compounds. Box and Comer (Current Drug Metabolism, 2008, 9, 869-878) fitted solubility data for 86 drugs to an equation based solely on log P. The General Solubility Equation of Jain and Yalkowsky, which accounts for the crystal lattice energy, was applied to the same data set and gives more accurate solubility predictions. In this simple comparison between two solubility prediction methods, we show that log P alone is only half of the solution, and that there is a need to include the melting point when dealing with crystalline solutes.