Chemical fragment arrays for rapid druggability assessment

Incorporation of early druggability assessment in the drug discovery process provides a means to prioritize target proteins for high-throughput screening.

A phase 1 study of lenvatinib, multiple receptor tyrosine kinase inhibitor, in Japanese patients with advanced solid tumors

Purpose

This phase 1 study aimed to assess the tolerability, safety, pharmacokinetics (PK), pharmacodynamics, and preliminary efficacy of lenvatinib capsules in Japanese patients with solid tumors when administered orally up to 24 mg on a once-daily (QD) continuous schedule.

Methods

Patients were enrolled in one of the two sequential cohorts (20 or 24 mg) of lenvatinib on a 28-day cycle based on the conventional 3 + 3 dose escalation design. Adverse events (AEs) were graded using the Common Terminology Criteria for Adverse Events, version 4.0. Tolerability was judged based on dose-limiting toxicities (DLTs) during Cycle 1. The drug was defined as tolerable when the incidence of DLTs was less than 33 %.

Results

Nine patients received lenvatinib [20 mg (n = 3); 24 mg (n = 6)]. No DLTs were observed. The most common AEs were thrombocytopenia, blood thyroid stimulating hormone increased, and hypertension (89 %), followed by leukopenia, headache, and proteinuria (78 %). The area under the concentration–time curve and maximum observed concentration increased dose proportionally. The PK profiles were similar to those in non-Japanese phase 1 studies. One patient with leiomyosarcoma showed a partial response, and three patients have maintained stable disease for more than 6 months.

Conclusions

The 24-mg QD continuous dose of lenvatinib was determined to be tolerable with encouraging anti-tumor activity in Japanese patients with solid tumors.

Prophylactic Use of Antiemetics for Prevention of Opioid-Induced Nausea and Vomiting: A Questionnaire Survey among Japanese Physicians

BACKGROUND

Antiemetics are being used both for the treatment and prophylaxis of opioid-induced nausea and vomiting (OINV) in clinical practice, despite the lack of evidence for the prophylactic benefit. Data regarding the actual status of prophylactic antiemetic use for OINV remain to be elucidated.

OBJECTIVE

The objective of this study was to evaluate the practice among Japanese physicians of the prophylactic use of antiemetics when starting opioids prescription for the prevention of opioid-induced nausea and vomiting.

METHODS

This questionnaire survey was targeted among physicians experienced in cancer pain treatment at two institutions of Japan (Nagoya University Hospital and Ichinomiya City Municipal Hospital). The questionnaire assessed the physicians' practice and beliefs regarding the prophylactic antiemetics prescription when they start opioids in patients with cancer pain.

RESULTS

Questionnaires were filled in and received from 112 physicians from two institutions. Eighty-two percent of physicians prescribed prophylactic antiemetics at the beginning of opioid prescription, and the most commonly prescribed drug for this purpose was prochlorperazine (88%).

CONCLUSION

Despite the lack of evidence, Japanese physicians commonly prescribe prophylactic antiemetics, most commonly prochlorperazine, for OINV. Prospective clinical trials are necessary to evaluate the efficacy of this practice.

Involvement of TRPV1 and TRPA1 in incisional intraoral and extraoral pain

Thermal and mechanical hypersensitivity in the injured region is a common complication. Although it is well known clinically that thermal and mechanical sensitivity of the oral mucosa is different from that of the skin, the mechanisms underlying injured pain of the oral mucosa remain poorly understood. The transient receptor potential (TRP) vanilloid 1 (TRPV1) and TRP ankyrin 1 (TRPA1) in primary afferent neurons are known to contribute to pathological pain. Therefore, we investigated whether TRPV1 and/or TRPA1 contribute to thermal and mechanical hypersensitivity following oral mucosa or whisker pad skin incision. Strong heat and mechanical and cold hypersensitivity was caused in the buccal mucosa and whisker pad skin following incisions. On day 3 after the incisions, the number of TRPV1-immunoreactive (IR) and TRPA1-IR trigeminal ganglion (TG) neurons innervating the buccal mucosa and whisker pad skin was significantly increased, and the number of TRPV1/TRPA1-IR TG neurons innervating whisker pad skin, but not the buccal mucosa, was significantly increased. Administration of the TRPV1 antagonist, SB366791, to the incised site produced a significant suppression of heat hyperalgesia in both the buccal mucosa and whisker pad skin, as well as mechanical allodynia in the whisker pad skin. Administration of the TRPA1 antagonist, HC-030031, to the incised site suppressed mechanical allodynia and cold hyperalgesia in both the buccal mucosa and whisker pad skin, as well as heat hyperalgesia in the whisker pad skin. These findings indicate that altered expressions of TRPV1 and TRPA1 in TG neurons are involved in thermal and mechanical hypersensitivity following the buccal mucosa and whisker pad skin incision. Moreover, diverse changes in the number of TRPV1 and TRPA1 coexpressed TG neurons in whisker pad skin-incised rats may contribute to the intracellular interactions of TRPV1 and TRPA1 associated with whisker pad skin incision, whereas TRPV1 and TRPA1 expression in individual TG neurons is involved in buccal mucosa-incised pain.

Morphological and functional changes in regenerated primary afferent fibres following mental and inferior alveolar nerve transection

BACKGROUND

It is important to know the mechanisms underlying pain abnormalities associated with inferior alveolar nerve (IAN) regeneration in order to develop the appropriate treatment for orofacial neuropathic pain patients. However, peripheral mechanisms underlying orofacial pain abnormalities following IAN regeneration are not fully understood.

METHODS

Head withdrawal threshold (HWT), jaw opening reflex (JOR) thresholds, single-fibre recordings of the regenerated mental nerve (MN) fibres, calcitonin gene-related peptide (CGRP), isolectin B4 (IB4), peripherin, neurofilament-200 (NF-200) and transient receptor potential vanilloid 1 (TRPV1) expression in trigeminal ganglion (TG) cells, and electron microscopic (EM) observations of the regenerated MN fibres were studied in MN- and IAN-transected (M-IANX) rats.

RESULTS

HWT to mechanical or heat stimulation of the mental skin was significantly lower in M-IANX rats compared with sham rats. Mean conduction velocity of action potentials recorded from MN fibres (n = 124) was significantly slower in M-IANX rats compared with sham rats. The percentage of Fluoro-Gold (FG)-labelled CGRP-, peripherin- or TRPV1-immunoreactive (IR) cells was significantly larger in M-IANX rats compared with that of sham rats, whereas that of FG-labelled IB4- and NF-200-IR cells was significantly smaller in M-IANX rats compared with sham rats. Large-sized myelinated nerve fibres were rarely observed in M-IANX rats, whereas large-sized unmyelinated nerve fibres were frequently observed and were aggregated in the bundles at the distal portion of regenerated axons.

CONCLUSIONS

These findings suggest that the demyelination of MN fibres following regeneration may be involved in peripheral sensitization, resulting in the orofacial neuropathic pain associated with trigeminal nerve injury.

Local application of Aqua Titan improves symptoms of temporomandibular joint muscle disorder: a preliminary study

Aqua Titan (AT), comprising microscopic titanium particles dispersed in water, has been reported to have beneficial effects on muscle tissue. This study investigated the effects of local application of AT on symptoms in patients with muscle disorders of the temporomandibular joint (TMJ) compared to patients with joint disorders of the TMJ. Sixteen patients with unilateral masseter muscle pain during motion (muscle disorder group) and six patients with unilateral TMJ pain during motion (joint disorder group) applied an AT-permeated patch over the painful area every night for 2 weeks. Symptoms were evaluated clinically at the initial visit and 1 and 2 weeks later. Clinical symptoms in the joint disorder group showed no tendency towards improvement after 2 weeks. In contrast, mouth opening range with/without pain, visual analogue scale (VAS) scores for pain during mouth opening and eating, and activities of daily living (ADL) scores in the muscle disorder group were improved significantly after 2 weeks. Multiple comparison tests in the muscle disorder group showed significant improvements in the VAS for eating and ADL score after 1 week. These results suggest that the AT patch has a potential supplementary role in the treatment of patients with muscle disorders of the TMJ.

Tofogliflozin, a novel sodium-glucose co-transporter 2 inhibitor, improves renal and pancreatic function in db/db mice

BACKGROUND AND PURPOSE

Although inhibition of renal sodium-glucose co-transporter 2 (SGLT2) has a stable glucose-lowering effect in patients with type 2 diabetes, the effect of SGLT2 inhibition on renal dysfunction in type 2 diabetes remains to be determined. To evaluate the renoprotective effect of SGLT2 inhibition more precisely, we compared the effects of tofogliflozin (a specific SGLT2 inhibitor) with those of losartan (an angiotensin II receptor antagonist) on renal function and beta-cell function in db/db mice.

EXPERIMENTAL APPROACH

The effects of 8-week tofogliflozin or losartan treatment on renal and beta-cell function were investigated in db/db mice by quantitative image analysis of glomerular size, mesangial matrix expansion and islet beta-cell mass. Blood glucose, glycated Hb and insulin levels, along with urinary albumin and creatinine were measured

KEY RESULTS

Tofogliflozin suppressed plasma glucose and glycated Hb and preserved pancreatic beta-cell mass and plasma insulin levels. No improvement of glycaemic conditions or insulin level was observed with losartan treatment. Although the urinary albumin/creatinine ratio of untreated db/db mice gradually increased from baseline, tofogliflozin or losartan treatment prevented this increase (by 50-70%). Tofogliflozin, but not losartan, attenuated glomerular hypertrophy. Neither tofogliflozin nor losartan altered matrix expansion.

CONCLUSIONS AND IMPLICATIONS

Long-term inhibition of renal SGLT2 by tofogliflozin not only preserved pancreatic beta-cell function, but also prevented kidney dysfunction in a mouse model of type 2 diabetes. These findings suggest that long-term use of tofogliflozin in patients with type 2 diabetes may prevent progression of diabetic nephropathy.

Tofogliflozin, a sodium/glucose cotransporter 2 inhibitor, attenuates body weight gain and fat accumulation in diabetic and obese animal models

OBJECTIVE

Tofogliflozin, a highly selective inhibitor of sodium/glucose cotransporter 2 (SGLT2), induces urinary glucose excretion (UGE), improves hyperglycemia and reduces body weight in patients with Type 2 diabetes (T2D). The mechanisms of tofogliflozin on body weight reduction were investigated in detail with obese and diabetic animal models.

METHODS

Diet-induced obese (DIO) rats and KKAy mice (a mouse model of diabetes with obesity) were fed diets containing tofogliflozin. Body weight, body composition, biochemical parameters and metabolic parameters were evaluated.

RESULTS

In DIO rats tofogliflozin was administered for 9 weeks, UGE was induced and body weight gain was attenuated. Body fat mass decreased without significant change in bone mass or lean body mass. Food consumption (FC) increased without change in energy expenditure, and deduced total calorie balance (deduced total calorie balance=FC-UGE-energy expenditure) decreased. Respiratory quotient (RQ) and plasma triglyceride (TG) level decreased, and plasma total ketone body (TKB) level increased. Moreover, plasma leptin level, adipocyte cell size and proportion of CD68-positive cells in mesenteric adipose tissue decreased. In KKAy mice, tofogliflozin was administered for 3 or 5 weeks, plasma glucose level and body weight gain decreased together with a reduction in liver weight and TG content without a reduction in body water content. Combination therapy with tofogliflozin and pioglitazone suppressed pioglitazone-induced body weight gain and reduced glycated hemoglobin level more effectively than monotherapy with either pioglitazone or tofogliflozin alone.

CONCLUSION

Body weight reduction with tofogliflozin is mainly due to calorie loss with increased UGE. In addition, tofogliflozin also induces a metabolic shift from carbohydrate oxidation to fatty acid oxidation, which may lead to prevention of fat accumulation and inflammation in adipose tissue and liver. Tofogliflozin may have the potential to prevent obesity, hepatic steatosis and improve insulin resistance as well as hyperglycemia.

Effect of SGLT2 inhibitors in a murine model of urinary tract infection with Candida albicans

AIMS

Urinary tract infection (UTI) is a common clinical problem in diabetic patients; however, the relationship between UTI and glucosuria remains uncertain. To investigate the relationship, we examined the effect of glucosuria induced by sodium glucose cotransporter 2 (SGLT2) inhibitors on the progression of UTI in mice.

METHODS

From 1 day before transurethral inoculation with Candida albicans, female mice were treated orally once a day with an SGLT2 inhibitor in different treatment regimens: (i) dapagliflozin at 10 mg/kg for 2, 3 or 7 days, (ii) dapagliflozin at 0.1, 1 or 10 mg/kg for 3 days and (iii) dapagliflozin, canagliflozin or tofogliflozin at 10 mg/kg for 3 days. To evaluate the ascending UTI, the kidneys were removed 6 days after the inoculation, and the number of viable C. albicans cells in kidney was measured as colony-forming units (CFU).

RESULTS

In mice treated with dapagliflozin, the number of C. albicans CFU in kidney increased in accordance with both treatment duration and dose. The number of CFU significantly increased when mice were treated with 10 mg/kg dapagliflozin or canagliflozin but not tofogliflozin. With dapagliflozin and canagliflozin, urine glucose concentration (UGC) significantly increased up to 24 h after drug administration; with tofogliflozin, UGC significantly increased only up to 12 h after drug administration.

CONCLUSIONS

Our data indicate that increased susceptibility to UTI is associated with a persistent increase in UGC.