Osamu Nemoto

Japanese guidance for use of biologics for psoriasis (the 2013 version)

The clinical use of adalimumab and infliximab, human anti‐tumor necrosis factor (TNF)‐α monoclonal antibodies, for psoriasis began in January 2010. In January 2011, ustekinumab, a human anti‐interleukin‐12/23p40 (IL‐12/23p40) monoclonal antibody, was newly approved as the third biologic with an indication for psoriasis. While all of these biologics are expected to exhibit excellent therapeutic effect for psoriasis and to contribute to the improvement of quality of life in patients, these drugs require careful safety measures to prevent adverse drug reactions, such as serious infections. The new guidance, an English version prepared by revising the Japanese Guidance/Safety Manual for Use of Biologics for Psoriasis 2011 (in Japanese), is intended to provide up‐to‐date, evidence‐based recommendations and safety measures on the use of biologics, and describes the optimal use of the three biologics, medical requirements for facilities for using biologics, details of safety measures against reactivation of tuberculosis and hepatitis B virus infection, and recommendable combination therapies with biologics.

Effect of topical phosphodiesterase 4 inhibitor E6005 on Japanese children with atopic dermatitis: Results from a randomized, vehicle-controlled exploratory trial.

This exploratory study was designed to evaluate the safety and efficacy profile of the topical phosphodiesterase 4 inhibitor E6005 in Japanese children with mild‐to‐moderate atopic dermatitis. The present randomized, multicenter study included 62 patients who were treated with 0.05% E6005, 0.2% E6005 or vehicle ointment twice daily for 2 weeks. Safety and pharmacokinetics were assessed with a focus on the occurrence of adverse events and the whole blood concentrations of E6005 and its metabolite. Exploratory efficacy evaluations included assessments of lesion severity and pruritus score. The 2‐week application of topical E6005 was safe and well tolerated with no cutaneous adverse events. The whole blood concentration of E6005 was quantified in only one subject receiving 0.2% E6005 treatment, while its major metabolite was undetectable. The 0.2% E6005 group showed a greater decrease in the severity score than the vehicle group (−45.94% vs −32.26%), although this difference was not statistically significant. Similarly, the treatment success rate according to the investigators global assessment of the total application sites was higher in the 0.2% E6005 group than in the vehicle group (34.4% vs 20.0%). Moreover, the 0.2% E6005 group showed a greater decrease in the pruritus score than the vehicle group (−37.5% vs −6.7%) in a predefined subpopulation. The efficacy of 0.05% E6005 treatment was comparable to that of vehicle treatment. These results suggest that topical 0.2% E6005 treatment is safe and effective in children with atopic dermatitis, although further large confirmatory clinical trials are warranted.

Effects of hydrocortisone on the adrenaline-adenylate cyclase system of the skin.

Using pig skin slices, we investigated the effects of hydrocortisone on the adenylate cyclase system of the skin. In short‐term experiments, hydrocortisone, when added singly or in combination with other stimulators of adenylate cyclase in the skin (adrenaline or histamine), had no effect on cyclic AMP accumulation. However, when skin slices were incubated with hydrocortisone for more than 6 h, the response to adrenaline differed, with a greater accumulation of cyclic AMP in the hydrocortisonetreated skin. This effect was seen at a concentration of more than 1 μM hydrocortisone and was most marked 48 h later, while responses to adrenaline in control skin gradually decreased and remained low.

Efficacy and safety of topical JTE-052, a Janus kinase inhibitor, in Japanese adult patients with moderate-to-severe atopic dermatitis: a phase II, multicentre, randomized, vehicle-controlled clinical study

JTE‐052 is a novel Janus kinase inhibitor presently under clinical development for the topical treatment of atopic dermatitis (AD).

Apremilast, an oral phosphodiesterase 4 inhibitor, in the treatment of Japanese patients with moderate to severe plaque psoriasis: Efficacy, safety and tolerability results from a phase 2b randomized controlled trial

Apremilast, an oral, small‐molecule phosphodiesterase 4 inhibitor, works intracellularly within immune cells to regulate inflammatory mediators. This phase 2b randomized, placebo‐controlled study evaluated efficacy and safety of apremilast among Japanese patients with moderate to severe plaque psoriasis. In total, 254 patients were randomized to placebo, apremilast 20 mg b.i.d. (apremilast 20) or apremilast 30 mg b.i.d. (apremilast 30) through week 16; thereafter, all placebo patients were re‐randomized to apremilast 20 or 30 through week 68. Efficacy assessments included achievement of 75% or more reduction from baseline in Psoriasis Area and Severity Index score (PASI‐75; primary) and achievement of static Physician Global Assessment (sPGA; secondary) score of 0 (clear) or 1 (minimal) at week 16. Safety was assessed through week 68. At week 16, PASI‐75 response rates were 7.1% (placebo), 23.5% (apremilast 20; P = 0.0032 vs placebo) and 28.2% (apremilast 30; P = 0.0003 vs placebo); sPGA response rates (score of 0 or 1) were 8.8% (placebo), 23.9% (apremilast 20; P = 0.0165 vs placebo) and 29.6% (apremilast 30; P = 0.0020 vs placebo). Responses were maintained with apremilast through week 68. Most common adverse events (AEs) with placebo, apremilast 20 and apremilast 30 (0–16 weeks) were nasopharyngitis (8.3%, 11.8%, 11.8%), diarrhea (1.2%, 8.2%, 9.4%), and abdominal discomfort (1.2%, 1.2%, 7.1%), respectively. Exposure‐adjusted incidence of these AEs did not increase with continued apremilast treatment (up to 68 weeks). Apremilast demonstrated efficacy and safety in Japanese patients with moderate to severe plaque psoriasis through 68 weeks that was generally consistent with prior studies.

A novel synthetic vitamin-A-like compound (a polyprenoic acid derivative: E-5166) inhibits UVB-stimulated epidermal ornithine decarboxylase activity

SummaryIrradiation of skin with ultraviolet B (UVB) stimulates epidermal activity of ornithine decarboxylase (ODC), a rate limiting polyamine biosynthesing enzyme. The maximum stimulation of ODC activity by UVB was found at 24 after irradiation. Systemic administration of a polyprenoic acid derivative (E-5166) significantly inhibited the UVB-stimulated ODC activity in a dose-dependent manner. The inhibitory effect of E-5166 on the UVB-stimulated ODC activity was found to begin at 5 mg/kg body weight. These results indicate that because it inhibits ODC activity E-5166 can be utilized for the treatment of hyperproliferative skin diseases.

Amenamevir, a novel helicase–primase inhibitor, for treatment of herpes zoster: A randomized, double‐blind, valaciclovir‐controlled phase 3 study

Amenamevir is a potent helicase–primase inhibitor and a novel class of antiviral agent other than nucleoside compounds, such as aciclovir, valaciclovir and famciclovir. This study is the first randomized, double‐blind, valaciclovir‐controlled phase 3 study to evaluate the efficacy and safety of amenamevir in Japanese patients with herpes zoster when treated within 72 h after onset of rash. A total of 751 patients were randomly assigned to receive either amenamevir 400 mg or 200 mg p.o. once daily or valaciclovir 1000 mg three times daily (daily dose, 3000 mg) for 7 days. The primary efficacy end‐point was the proportion of cessation of new lesion formation by day 4 (“day 4 cessation proportion”). The day 4 cessation proportions for amenamevir 400 and 200 mg and valaciclovir were 81.1% (197/243), 69.6% (172/247) and 75.1% (184/245), respectively. Non‐inferiority of amenamevir 400 mg to valaciclovir was confirmed by a closed testing procedure. Days to cessation of new lesion formation, complete crusting, healing, pain resolution and virus disappearance were evaluated as secondary end‐points. No significant differences were observed in any of the treatment groups. Amenamevir 400 and 200 mg were well tolerated as well as valaciclovir. The proportions of patients who experienced drug‐related adverse events were 10.0% (25/249), 10.7% (27/252) and 12.0% (30/249) with amenamevir 400 and 200 mg and valaciclovir, respectively. In conclusion, amenamevir 400 mg appears to be effective and well tolerated for treatment of herpes zoster in immunocompetent Japanese patients.

Effects of 12-o-tetradecanoylphorbol-13-acetate and polyprenoic acid derivative on calcium-activated phospholipid-dependent protein kinase of pig skin

Summary12-o-Tetradecanoylphorbol-13-acetate (TPA) activates calcium-activated, phospholipid-dependent protein kinase (protein kinase C) partially purified in an ion exchange column from pig epidermis. Protein kinase C was activated by TPA in a concentration-dependent manner with simultaneous addition of Ca2+ and phospholipid. Polyprenoic acid derivative (E5166) which is a newly synthesized retinoic acid derivative, inhibited the TPA activation of protein kinase C. This inhibition may explain the mechanisms by which retinoids inhibit TPA-induced tumor promotion.

Effects of calcium and calcium-ionophore on the outgrowing epidermis--possible activation of epidermal phospholipase A2.

Using an in vitro explant culture system of pig skin, the effects of calcium and calcium‐ionophore on the outgrowing epidermis were studied. The optimum concentration of calcium on the rates of epidermal outgrowth was 1.0 mM and that of mitosis was around 1.2 mM. Ionophore A23187 (Ionophore) significantly stimulated both the rates of epidermal outgrowth and the mitosis of the outgrowing epidermis. This stimulation was partially blocked by the addition of hydrocortisone.

Phase 1 studies to assess the safety, tolerability and pharmacokinetics of JTE-052 (a novel Janus kinase inhibitor) ointment in Japanese healthy volunteers and patients with atopic dermatitis

The purpose of the present two phase 1 studies was to assess the safety, tolerability and pharmacokinetics for topical application of a novel Janus kinase (JAK) inhibitor, JTE‐052, in Japanese healthy adult male volunteers and Japanese adult patients with atopic dermatitis (AD). Additionally, exploratory investigation was performed on the efficacy for disease severity and pruritus score in AD patients. In the QBX1‐1 study, the cutaneous safety of JTE‐052 ointment by a patch test and a photo patch test was assessed in an intra‐individual comparative study using placebo ointment, white petrolatum and non‐application as comparators. The study demonstrated that JTE‐052 ointment would be associated with a low potential for phototoxicity but had no potential for skin irritation or photoallergy. In the QBX1‐2 study, it was revealed that the systemic exposure to JTE‐052 in both healthy volunteers with normal skin and AD patients with inflamed skin was low in application of not only 1% but also 3% JTE‐052 ointment. JTE‐052 ointments of 1% and 3% were generally safe and well tolerated in both populations. In a repeated twice‐daily application for 7 days, the efficacy of JTE‐052 ointment to AD patients was observed with both 1% and 3% ointments in the exploratory investigations evaluated by Eczema Area and Severity Index, Investigators Global Assessment and Numeric Rating Scale assessments. The mean scores for each assessment declined from the baseline throughout the study. These results suggest that the treatment of JTE‐052 ointment is generally safe and effective in AD patients, although further large confirmatory studies are needed.