Efficacy of Mirogabalin for Taxane-associated Chemotherapy-induced Peripheral Neuropathy in Perioperative Chemotherapy for Early Breast Cancer.

BACKGROUND/AIM: Treatment with taxanes can result in chemotherapy-induced peripheral neuropathy (CIPN). We investigated the efficacy and safety of mirogabalin for the treatment of CIPN in patients who had been administered perioperative chemotherapy including taxane-based agents for breast cancer. PATIENTS AND METHODS: We retrospectively analyzed the case of 43 patients with early breast cancer who received a taxane as perioperative chemotherapy and were administered mirogabalin at the diagnosis of CIPN. RESULTS: Thirty-six patients (83.7%) had grade 1 CIPN and the other seven patients (16.3%) had grade 2 CIPN. The median mirogabalin dose was 10 mg (5-30 mg). CIPN improved from grade 1 to 0 in 12 patients (27.9%) and from grade 2 to 1 in one patient (2.3%); 13 (30.2%) patients thus had an objective therapeutic response. There were no cases in which chemotherapy was reduced or discontinued due to CIPN. Adverse events were evaluated by Common Terminology Criteria for Adverse Events and included five cases of dizziness (11.7%), three of somnolence (7.0%), and two of nausea (4.7%), all of which were grade ≤2. There were no cases of serious (grade ≥3) adverse effects. CONCLUSION: Mirogabalin may be effective and safe for treating CIPN of patients who receive a taxane in a perioperative breast cancer setting.

Safety of mirogabalin and pregabalin in Japanese patients with neuropathic pain: a retrospective cohort study.

BACKGROUND: Few studies have compared the safety risks between the gabapentinoids, pregabalin, and mirogabalin in post-marketing clinical settings. We assessed reported events associated with gabapentinoid use in patients with neuropathic pain. RESEARCH DESIGN AND METHODS: We conducted a retrospective cohort study between September 2020 and December 2020 using the community pharmacies records in Japan. The pharmacists identified new vs. prevalent users of mirogabalin and pregabalin in September 2020 and reported data regarding baseline and adverse events to the Japan Pharmaceutical Association using web-based questionnaires. The incidence of events and hazard ratio (HR) were consequently compared. RESULTS: New users of mirogabalin and pregabalin were identified (n = 1,650 and 2,244; mean age (SD): 69 (15) and 68 (16) years; women: 59% and 56%, respectively). Although serious events were not reported, a marked difference in HRs of common adverse events, including somnolence (1.6), dizziness (1.3), nausea (2.8), edema (3.1), and acetaminophen (2.0)/antidepressant (2.4) addition, was observed. CONCLUSION: No new serious safety concerns were found for mirogabalin and pregabalin use in patients with neuropathic pain, although the HR of some events indicated increased risk among mirogabalin users. However, further studies are needed as estimates for events occurring in small numbers with wide confidence intervals.

Safety, Tolerability and Pharmacokinetics of Single and Multiple Doses of Mirogabalin in Healthy Chinese Participants: A Randomized, Double-Blind, Placebo-Controlled Study.

INTRODUCTION: Mirogabalin is a treatment option for patients with neuropathic pain; however, safety, tolerability, and pharmacokinetics (PK) data specifically for Chinese individuals are limited to a single-dose study. We aimed to assess these for both single- and multiple-dose mirogabalin in healthy Chinese participants. METHODS: In this randomized, double-blind, placebo-controlled, phase I study, 54 healthy Chinese men and women aged 18-45 years were randomly allocated to receive single- (5, 10, or 15 mg, daily) or multiple-dose (5 mg titrated to 15 mg, twice-daily, over 22 days) oral mirogabalin or placebo. In each of three single-dose groups, 10 participants received mirogabalin and 2 received placebo; in the multiple-dose group, 14 participants received mirogabalin and 4 received placebo. The primary endpoints were PK, safety, and tolerability variables, including treatment-emergent adverse events (TEAEs), laboratory tests, and vital signs. PK data were collected for both single- and multiple-dose cohorts and evaluated by non-compartmental analysis. RESULTS: Single- and multiple-dose mirogabalin was generally well tolerated with no deaths, serious TEAEs, or TEAEs leading to treatment discontinuation. Frequently reported TEAEs included dizziness, nystagmus, increased blood triglycerides, headache, and increased blood uric acid and creatine phosphokinase. Single-dose mirogabalin was rapidly absorbed (median time to maximum plasma concentration, 1.00 h) and eliminated (mean terminal elimination half-life, 2.57-3.08 h). The exposure was approximately dose-proportional. In the multiple-dose cohort, the trough plasma concentration increased dose-proportionally, and exposure and clearance were comparable to that following a single 15-mg dose. The mean cumulative amount excreted into urine up to 48 h post-dose increased in a dose-proportional manner, the mean cumulative percentage excreted into urine was 61.9%-74.3%, and renal clearance remained relatively constant. CONCLUSION: Consistent with previous phase I studies in other populations, mirogabalin was safe and well tolerated in healthy Chinese participants at single and multiple doses of up to 15 mg twice-daily.

Bicyclic Ligand-Biased Agonists of S1P1: Exploring Side Chain Modifications to Modulate the PK, PD, and Safety Profiles.

Sphingosine-1-phosphate (S1P) binds to a family of sphingosine-1-phosphate G-protein-coupled receptors (S1P1-5). The interaction of S1P with these S1P receptors has a fundamental role in many physiological processes in the vascular and immune systems. Agonist-induced functional antagonism of S1P1 has been shown to result in lymphopenia. As a result, agonists of this type hold promise as therapeutics for autoimmune disorders. The previously disclosed differentiated S1P1 modulator BMS-986104 (1) exhibited improved preclinical cardiovascular and pulmonary safety profiles as compared to earlier full agonists of S1P1; however, it demonstrated a long pharmacokinetic half-life (T1/2 18 days) in the clinic and limited formation of the desired active phosphate metabolite. Optimization of this series through incorporation of olefins, ethers, thioethers, and glycols into the alkyl side chain afforded an opportunity to reduce the projected human T1/2 and improve the formation of the active phosphate metabolite while maintaining efficacy as well as the improved safety profile. These efforts led to the discovery of 12 and 24, each of which are highly potent, biased agonists of S1P1. These compounds not only exhibited shorter in vivo T1/2 in multiple species but are also projected to have significantly shorter T1/2 values in humans when compared to our first clinical candidate. In models of arthritis, treatment with 12 and 24 demonstrated robust efficacy.

Cost-effectiveness of mirogabalin for the treatment of post-herpetic neuralgia in Taiwan.

Objectives: To assess the cost-effectiveness of mirogabalin versus no treatment or pregabalin in patients with post-herpetic neuralgia (PHN) from a third-party perspective in Taiwan.Methods: A Markov model, which was developed with 2-week cycles and 1-year time horizon from the Taiwanese National Health Insurance Administration perspective, consisted of three health states: "mild," "moderate," and "severe" pain. Average daily pain score (ADPS) was assessed at the end of each cycle. Patients either remained in, or transitioned from, their assigned health state to a different state according to their pain score changes. All patients entered the model in "moderate" (4 ≤ ADPS <7) or "severe" (7 ≤ ADPS ≤ 10) pain health states. Efficacy data was informed by the pivotal Phase III trial, or by a network meta-analysis (NMA). Utility values were obtained from published literature and cost data from Taiwanese clinical experts and the Taiwan National Health Insurance Administration, using 2018 New Taiwan dollar (NT$). Probabilistic analysis was conducted to test the robustness of base case results.Results: Head-to-head analysis showed mirogabalin 30 mg to be cost-effective versus placebo in PHN. The deterministic analysis estimated a quality-adjusted life years gain of 0.041 at an ICER of NT$11,231 (US$365) versus no treatment (ICER: NT$274,567 [US$8,900]). In the NMAs, mirogabalin was cost-effective compared to pregabalin 150 mg (ICER: NT$515,881 [US$16,720]) and 300 mg (ICER: NT$201,671 [US$6,535]). Mirogabalin 30 mg dominated pregabalin 600 mg. Results from sensitivity and scenario analyses confirmed these results.Conclusion: Mirogabalin 30 mg, a potent and selective α2δ ligand, is a cost-effective treatment option for PHN in Taiwan, with ICERs below the willingness-to-pay threshold.

Efficacy and safety of mirogabalin for the treatment of fibromyalgia: results from three 13-week randomized, double-blind, placebo- and active-controlled, parallel-group studies and a 52-week open-label extension study.

Objective: To investigate the efficacy and safety of mirogabalin, an α2δ ligand, in patients with fibromyalgia (FM). Methods: In three 13-week, multicenter, double-blind, phase 3 studies (studies A, B, and C), patients with FM (n = 1293, 1270, and 1301, respectively) were randomized (1:1:1:1) to placebo, pregabalin 150 mg twice daily, mirogabalin 15 mg once daily or mirogabalin 15 mg twice daily. The primary endpoint was the change in weekly average daily worst pain score (ADPS) at week 13. Key secondary endpoints included Patient Global Impression of Change and change in the Fibromyalgia Impact Questionnaire total score. Long-term safety of mirogabalin was assessed in a 52-week extension study. Results: Neither mirogabalin dose demonstrated a significant ADPS reduction from baseline vs. placebo at week 13 in any of the three studies. Pregabalin significantly reduced ADPS from baseline vs. placebo in studies B and C (p = .0008 and .0001, respectively). The effect of mirogabalin compared with placebo on key secondary endpoints was variable across the studies. Mirogabalin was well tolerated by most patients in the phase 3 studies; no unexpected adverse events occurring during the 52-week extension study. Conclusion: While both mirogabalin doses were well tolerated by most patients and showed potential for reducing pain associated with FM, the primary endpoint of significant pain reduction in patients on mirogabalin compared with placebo was not achieved in any of the three randomized controlled studies. Clinical trial registration: NCT02146430; NCT02187159; NCT02187471; and NCT02234583 (extension study).

Mirogabalin: First Global Approval.

Mirogabalin besylate (hereafter mirogabalin) [Tarlige®] is an orally administered gabapentinoid developed by Daiichi Sankyo for the treatment of peripheral neuropathic pain (PNP), including diabetic PNP and post-herpetic neuralgia. The drug binds to and modulates the α2δ-1 subunit of the voltage-gated calcium channels widely found in the nervous system in areas that mediate pain transmission and processing. Mirogabalin has a unique binding profile and long duration of action. The drug is approved in Japan for the treatment of PNP and is in clinical development for this indication elsewhere in Asia. Clinical development of the drug for fibromyalgia pain was discontinued in the USA and EU after the primary endpoint was not met in phase 3 trials. No recent reports of development have been identified for PNP in the USA or India or for fibromyalgia pain in Australia, India, New Zealand, Russia, Argentina, Belarus, Chile, Colombia, Israel, Mexico, Switzerland, Canada, Serbia or South Africa. This article summarizes the milestones in the development of mirogabalin leading to this first approval for PNP.

Pharmacokinetics, Pharmacodynamics, Safety, and Tolerability of Mirogabalin When Coadministered With Lorazepam, Zolpidem, Tramadol, or Ethanol: Results From Drug-Drug Interaction Studies in Healthy Subjects.

Four randomized, double-blind, placebo-controlled, 4-period drug-drug interaction studies were conducted in healthy subjects to evaluate the pharmacokinetic and pharmacodynamic (PD) interactions between mirogabalin and commonly used central nervous system depressants. Mirogabalin or placebo was administered alone or with single-dose lorazepam, zolpidem, tramadol, ethanol, or interacting drug placebo. Safety was assessed and serial samples for pharmacokinetic parameters were collected for up to 48 hours postdose. PD assessments included body sway (except tramadol), digit symbol substitution test, vertigo symptom scale short form, brief ataxia rating scale, and the Bond and Lader visual analog scale. Coadministration of mirogabalin with any of the 4 drugs did not cause any clinically relevant pharmacokinetic interactions. Peak mirogabalin concentration decreased by 28% (least squares mean ratio, 0.72; 90% confidence interval, [CI] 0.67, 0.76) following tramadol coadministration, and increased by 20% (least squares mean ratio, 1.20; 90%CI, 1.12, 1.28) following ethanol coadministration. Mirogabalin alone had little to no effect on PD parameters, but coadministration of mirogabalin with either lorazepam or ethanol increased the PD effects in body sway and digit symbol substitution test assays. Mirogabalin/lorazepam and mirogabalin/zolpidem increased occurrence of somnolence. Increased incidence of nausea and headache was noted with mirogabalin/tramadol and mirogabalin/ethanol, respectively.

A Randomized, Placebo-Controlled, Double-Blind Study of the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of Single and Repeated Doses of Mirogabalin in Healthy Asian Volunteers.

Mirogabalin is a novel, preferentially selective α2 δ-1 ligand under investigation to treat neuropathic pain. The purpose of this study was to evaluate the safety, tolerability, and pharmacokinetics of various doses of mirogabalin in healthy subjects of different ethnicities. This randomized, placebo-controlled, double-blind, sequential, ascending-dose study evaluated single (10-40 mg) and repeated (10, 15 mg twice a day) doses of mirogabalin in Japanese subjects, and a single dose of mirogabalin in Korean, Chinese, and white subjects. Mirogabalin was rapidly absorbed, with a median time to maximum plasma concentration of 1 hour, and rapidly eliminated, with a mean elimination half-life of 2 to 3 hours. Single-dose mirogabalin pharmacokinetic parameters were comparable between Asian and white subjects. Exposure increased proportionally as mirogabalin dose increased in Japanese subjects. Mean mirogabalin steady-state clearance and volume of distribution values were comparable across dose levels. No accumulation of mirogabalin was observed on repeated dosing in Japanese subjects. Mirogabalin had an acceptable safety and tolerability profile in Asian and white subjects at doses up to 15 mg twice a day for 7 days. The most common treatment-emergent adverse events (somnolence, headache, and dizziness) were consistent with the known mechanism of action and safety profile of mirogabalin.

Binding Characteristics and Analgesic Effects of Mirogabalin, a Novel Ligand for the α2δ Subunit of Voltage-Gated Calcium Channels.

Mirogabalin ([(1R,5S,6S)-6-(aminomethyl)-3-ethylbicyclo[3.2.0]hept-3-en-6-yl]acetic acid), a novel ligand for the α2δ subunit of voltage-gated calcium channels, is being developed to treat pain associated with diabetic peripheral neuropathy and postherpetic neuralgia. In the present study, we investigated the in vitro binding characteristics and in vivo analgesic effects of mirogabalin compared with those of pregabalin, a standard α2δ ligand. Mirogabalin showed potent and selective binding affinities for the α2δ subunits, while having no effects on 186 off-target proteins. Similar to pregabalin, mirogabalin did not show clear subtype selectivity (α2δ-1 vs. α2δ-2) or species differences (human vs. rat). However, in contrast to pregabalin, mirogabalin showed greater binding affinities for human α2δ-1, human α2δ-2, rat α2δ-1, and rat α2δ-2 subunits; further, it had a slower dissociation rate for the α2δ-1 subunit than the α2δ-2 subunit. Additionally, in experimental neuropathic pain models, partial sciatic nerve ligation rats and streptozotocin-induced diabetic rats, mirogabalin showed more potent and longer lasting analgesic effects. In safety pharmacological evaluations, mirogabalin and pregabalin inhibited rota-rod performance and locomotor activity in rats; however, the safety indices of mirogabalin were superior to those of pregabalin. In conclusion, mirogabalin shows potent and selective binding affinities for the human and rat α2δ subunits, and slower dissociation rates for the α2δ-1 subunit than the α2δ-2 subunit. It shows potent and long-lasting analgesic effects in rat models of neuropathic pain, and wider safety margins for side effects of the central nervous system. These properties of mirogabalin can be associated with its unique binding characteristics.

Pharmacokinetics and Safety of a Single Oral Dose of Mirogabalin in Japanese Subjects With Varying Degrees of Renal Impairment.

Mirogabalin (DS-5565) is a novel preferentially selective α2 δ-1 ligand being developed for the treatment of diabetic peripheral neuropathic pain and postherpetic neuralgia. The current multicenter open-label study determined the effect of varying degrees of renal impairment on the pharmacokinetics and safety of a single dose of mirogabalin 5 mg in Japanese subjects. A total of 30 subjects (6 subjects per renal function category [normal, mild, moderate, or severe impairment; and end-stage renal disease (ESRD)]) were enrolled and completed the study. The AUClast increased with severity of renal impairment; the geometric least-squares mean ratios of AUClast compared with subjects with normal renal function were 1.3, 1.9, 3.6, and 5.3 for patients with mild, moderate, and severe impairment and ESRD, respectively. In accordance with this AUClast increase, apparent total body clearance (CL/F), renal clearance (CLr), and the cumulative percentage of mirogabalin dose excreted into urine all decreased with severity of renal impairment. There were no deaths and no severe treatment-related adverse events (TEAEs), serious TEAEs, or TEAEs resulting in study discontinuation. Mirogabalin was well tolerated in Japanese subjects with normal renal function and those with mild to severe renal impairment. It was also tolerated in subjects with ESRD but with a higher incidence of TEAEs. The most frequently reported TEAEs were dizziness (ESRD, n = 3), somnolence (ESRD, n = 2), and vomiting (ESRD, n = 2). Based on these data, a mirogabalin dose adjustment will be considered in Japanese subjects with moderate to severe renal impairment and those with ESRD.

Exposure-response modeling of average daily pain score, and dizziness and somnolence, for mirogabalin (DS-5565) in patients with diabetic peripheral neuropathic pain.

Mirogabalin (DS-5565) is an α2δ-1 ligand being developed for pain associated with diabetic peripheral neuropathy, fibromyalgia, and postherpetic neuralgia. Nonlinear mixed-effects analyses were performed on average daily pain and on the incidence of the adverse events dizziness and somnolence. These models were used to predict the dose of mirogabalin equivalent to pregabalin and the probability of meaningful reduction in pain compared with placebo and pregabalin. In addition, regimen effects were evaluated for reductions of adverse events. Mirogabalin was estimated to be 17-fold more potent than pregabalin. The effectiveness of 150 mg pregabalin, dosed twice daily, attenuated by week 5. Therefore, the estimated mechanism-based equivalent dose (ED) of 17.7 mg mirogabalin was higher than that predicted to achieve comparable pain reduction. If attenuation of the pregabalin effect is real, mirogabalin doses lower than the ED could yield comparable pain reduction, albeit with less differentiation in pain from placebo. The incidence rate of dizziness and somnolence decreased over time. Twice-daily dosing of mirogabalin was predicted to yield a lower incidence rate of dizziness than once-daily dosing; thus, titration of dosages should reduce adverse event rates. These model results were used to influence phase 3 dosing selection.

mGlu2 Receptor Agonism, but Not Positive Allosteric Modulation, Elicits Rapid Tolerance towards Their Primary Efficacy on Sleep Measures in Rats.

G-protein-coupled receptor (GPCR) agonists are known to induce both cellular adaptations resulting in tolerance to therapeutic effects and withdrawal symptoms upon treatment discontinuation. Glutamate neurotransmission is an integral part of sleep-wake mechanisms, which processes have translational relevance for central activity and target engagement. Here, we investigated the efficacy and tolerance potential of the metabotropic glutamate receptors (mGluR2/3) agonist LY354740 versus mGluR2 positive allosteric modulator (PAM) JNJ-42153605 on sleep-wake organisation in rats. In vitro, the selectivity and potency of JNJ-42153605 were characterized. In vivo, effects on sleep measures were investigated in rats after once daily oral repeated treatment for 7 days, withdrawal and consecutive re-administration of LY354740 (1-10 mg/kg) and JNJ-42153605 (3-30 mg/kg). JNJ-42153605 showed high affinity, potency and selectivity at mGluR2. Binding site analyses and knowledge-based docking confirmed the specificity of JNJ-42153605 at the mGluR2 allosteric binding site. Acute LY354740 and JNJ-42153605 dose-dependently decreased rapid eye movement (REM) sleep time and prolonged its onset latency. Sub chronic effects of LY354740 on REM sleep measures disappeared from day 3 onwards, whereas those of JNJ-42153605 were maintained after repeated exposure. LY354740 attenuated REM sleep homeostatic recovery, while this was preserved after JNJ-42153605 administration. JNJ-42153605 enhanced sleep continuity and efficiency, suggesting its potential as an add-on medication for impaired sleep quality during early stages of treatment. Abrupt cessation of JNJ-42153605 did not induce withdrawal phenomena and sleep disturbances, while the initial drug effect was fully reinstated after re-administration. Collectively, long-term treatment with JNJ-42153605 did not induce tolerance phenomena to its primary functional effects on sleep measures, nor adverse effects at withdrawal, while it promoted homeostatic recovery sleep. From the translational perspective, the present rodent findings suggest that mGluR2 positive allosteric modulation has therapeutic potential based on its superior long term efficacy over agonists in psychiatric disorders, particularly of those commonly occurring with REM sleep overdrive.

Efficacy and safety of the dual L- and T-type calcium channel blocker, ACT-280778: a proof-of-concept study in patients with mild-to-moderate essential hypertension.

ACT-280778 is an oral, non-dihydropyridine, dual L-/T-type calcium channel blocker. This phase 2a, double-blind, randomized, placebo- and active-controlled study investigated the efficacy and safety of 10 mg ACT-280778. Patients with mild-to-moderate essential hypertension received once-daily placebo (n=53), ACT-280778 10 mg (n=52) or amlodipine 10 mg (n=54) for 4 weeks. The primary end point was the change from baseline to week 4 in placebo-adjusted mean trough sitting diastolic blood pressure (SiDBP) with ACT-280778. Tolerability was assessed by recording treatment-emergent adverse events (TEAEs). Baseline clinical characteristics were similar across groups. No significant difference was observed at week 4 in mean trough SiDBP between placebo (-9.9 (95% confidence limit (CL) -12.7, -7.0) mm Hg) and ACT-280778 (-9.5 (-12.4, -6.5) mm Hg; P=0.86); amlodipine reduced mean trough SiDBP by -16.8 (-19.0, -14.5) mm Hg, confirming assay validity. Change in mean PR interval at week 4 (pre-dose) differed between placebo (-1.0 (95% CL -4.4, 2.3) ms) and ACT-280778 (6.5 (3.5, 9.6) ms); amlodipine did not increase PR interval (1.1 (-1.6, 3.9) ms).Treatment-emergent adverse events (TEAE) frequency was 32.1% (placebo), 32.7% (ACT-280778) and 33.3% (amlodipine). The most common TEAEs were headache, peripheral edema, hypertension and second-degree atrioventricular block. ACT-280778 (10 mg) did not lower blood pressure in mild-to-moderate hypertension.

Efficacy and safety of mirogabalin (DS-5565) for the treatment of diabetic peripheral neuropathic pain: a randomized, double-blind, placebo- and active comparator-controlled, adaptive proof-of-concept phase 2 study.

OBJECTIVE: We aimed to identify doses of mirogabalin (DS-5565) providing clinically meaningful efficacy with manageable side effects for treatment of diabetic peripheral neuropathic pain (DPNP). RESEARCH DESIGN AND METHODS: Adults (≥18 years) with type 1 or 2 diabetes, HbA1c ≤10% at screening, and DPNP for ≥6 months were eligible for study participation. Subjects (n = 452) were randomized (2:1:1:1:1:1:1 ratio) to placebo, dose-ranging mirogabalin (5, 10, 15, 20, and 30 mg/day), or pregabalin (300 mg/day) for 5 weeks. The primary end point was weekly change in average daily pain score (ADPS; 0 to 10 numeric rating scale) from baseline to week 5 (minimally meaningful effect, ≥1.0-point decrease versus placebo). ANCOVA was conducted using last observation carried forward, and treatment effect least squares (LS) means were provided for each contrast. Safety assessments included adverse events (AEs), clinical laboratory tests, and electrocardiograms. RESULTS: LS mean differences in change in ADPS from baseline to week 5 versus placebo were -0.22, -0.53, -0.94, -0.88, and -1.01 for the mirogabalin 5-, 10-, 15-, 20-, and 30-mg/day treatment groups, respectively, and -0.05 in the pregabalin group (P < 0.05 versus placebo for mirogabalin 15, 20, and 30 mg/day). Most frequent AEs (n = 277) were primarily mild to moderate dizziness (9.4%), somnolence (6.1%), and headache (6.1%); otherwise, mirogabalin was well tolerated. CONCLUSIONS: Mirogabalin 15, 20, and 30 mg/day had statistically significant reductions in ADPS versus placebo, and mirogabalin 30 mg/day also met the criteria of minimally meaningful effect. Mirogabalin may be a promising new treatment option for patients with DPNP.

Role of 5-HT(1A)- and 5-HT(2A) receptors for the murine model of the serotonin syndrome.

INTRODUCTION: The serotonin (5-HT) syndrome (SS) in man covers side effects of drugs in over dose that increase synaptic 5-HT concentration or directly activate 5-HT receptors. The SS is characterized by mental state alterations, neuromuscular excitation, and autonomic dysregulation. In mice, a set of behavioral and autonomic responses can be induced by the same serotonergic drugs as in man. The role of the 5-HT1A receptor for the murine SS has been extensively studied and several responses have been attributed to 5-HT1A receptor activation. So far, 5-HT2A receptor activation is thought to induce head twitches and hypothermia. The aim of this study is to define the impact of the 5-HT2A and the 5-HT1A receptor for different SS-like responses. METHODS: The effects of the full 5-HT1A receptor agonist 8-OH-DPAT, the partial 5-HT1A agonist buspirone, and the 5-HT2A receptor agonist TCB-2 were investigated in male NMRI mice. The responses were compared with the effects induced by the 5-HT precursor 5-HTP. RESULTS: Flat body posture, hindlimb abduction, Straub tail, tremor, piloerection and decreased rearing were observed after 8-OH-DPAT treatment. A similar set of responses was seen after administration of buspirone. However, the Straub tail response did not occur, probably due to the lower efficacy of buspirone at postsynaptic 5-HT1A receptors. As expected, TCB-2 induced head twitches, but also evoked flat body posture, hindlimb abduction, and piloerection, and decreased the numbers of rearings and defecation boli. DISCUSSION: The Straub tail response seems to be a specific sign for postsynaptic 5-HT1A receptor activation. In addition, the 5-HT2A receptor has more impact on the 5-HT syndrome than previously suggested. By inducing the broadest spectrum of signs, 5-HTP seems to be suitable as a positive control when investigating the 5-HT syndrome in mice. In summary, the murine model of the SS is a valid tool for preclinical studies to screen drugs and drug combinations for the risk to cause an SS in man.

Tolerability and pharmacokinetics of ACT-280778, a novel nondihydropyridine dual L/T-type calcium channel blocker: early clinical studies in healthy male subjects using adaptive designs.

ACT-280778 is a novel nondihydropyridine dual L/T-type calcium channel blocker. Two clinical studies (AC-067-101 and AC-067-102) were conducted to characterize its safety, tolerability, and pharmacokinetics in healthy male subjects after oral administration of single and multiple doses. Both trials were single-center, randomized, double-blind, placebo-controlled, adaptive design, ascending-dose studies, in which ACT-280778 was administrated as single doses of 2, 5, 15, or 40 mg, or as once-daily doses of 5 or 15 mg for 7 days. Single and multiple doses up to and including 15 mg were well tolerated, and no serious or severe adverse event was reported in either study. A single dose of 40 mg was associated with abnormal electrocardiogram findings resulting in the discontinuation of further treatment at this dose or higher doses. ACT-280778 was rapidly absorbed, and larger than dose-proportional increases of the maximum plasma concentration and area under the plasma concentration-time curve were observed. Food intake delayed the time to maximum plasma concentration and doubled exposure. Urinary excretion of unchanged ACT-280778 was negligible, and accumulation at steady state was modest. Overall, pharmacokinetic and tolerability profiles of ACT-280778 observed in these 2 studies warranted further evaluation of ACT-280778 in a proof-of-concept study in patients with hypertension.

Pesticide risk assessment in flower greenhouses in Argentina: the importance of manipulating concentrated products.

An evaluation of the Potential Dermal Exposure of workers to endosulfan and procymidone at the mix/load and application stages was done in small floricultural production units in Argentina. Seven experiments were performed with different operators under typical greenhouse conditions, based on the whole body dosimetry methodology. These results indicate that the mean Potential Dermal Exposure of the application step was 45.0 ± 55.0 mL h(-1) with the highest proportion on torso, head, arms and hands. When the mix/load and application stages were compared, the first was found to contribute the most to the total exposure. Also, the Margin of Safety for the different operations was calculated, and a pesticide surrogate was developed and used to make comparative evaluations of hand exposure for different groups of operators. These results emphasize the importance of the mix/load stage in the exposure process.

Antidepressant hyperforin up-regulates VEGF in CNS tumour cells.

Vascular endothelial growth factor (VEGF) is a key player in neo-angiogenesis; it sustains the progression of solid neoplasias, brain tumours included. It has recently been demonstrated that the use of antidepressants correlates with increasing VEGF levels in the central nervous system (CNS). In order to elucidate whether the most used natural antidepressant [St. John's wort (SJW) extract] modulates VEGF expression, possible relationship between≤µM hyperforin (Hyp, the bioactive component in SJW) and VEGF in CNS tumours has been now examined in medulloblastoma and glioblastoma cells. Real-time PCR and ELISA revealed that under Hyp VEGF expression increased more than three fold in DAOY medulloblastoma cells; while, U87 glioblastoma cells - constitutively expressing high VEGF levels - showed no significant differences. Moreover, Hyp induced endothelial pro-angiogenic behaviour in a multi-parametric Matrigel colonisation assay, and down-modulation of pro-MMP-2 and pro-MMP-9 activities as measured by gelatin zymography. Should these results be confirmed in vivo for this and other types of CNS tumour, the antidepressant use of SJW extracts must be carefully re-considered, in particular for brain tumour patients.

Serratia odorifera: analysis of volatile emission and biological impact of volatile compounds on Arabidopsis thaliana.

Bacteria emit a wealth of volatiles. The combination of coupled gas chromatography/mass spectrometry (GC/MS) and proton-transfer-reaction mass spectrometry (PTR-MS) analyses provided a most comprehensive profile of volatiles of the rhizobacterium Serratia odorifera 4Rx13. An array of compounds, highly dominated by sodorifen (approximately 50%), a bicyclic oligomethyl octadiene, could be detected. Other volatiles included components of the biogeochemical sulfur cycle such as dimethyl disulfide (DMDS), dimethyl trisulfide and methanethiol, terpenoids, 2-phenylethanol, and other aromatic compounds. The composition of the bouquet of S. odorifera did not change significantly during the different growth intervals. At the beginning of the stationary phase, 60 µg of volatiles per 24 h and 60 easily detectable components were released. Ammonia was also released by S. odorifera, while ethylene, nitric oxide (NO) and hydrogen cyanide (HCN) could not be detected. Dual culture assays proved that 20 µmol DMDS and 2.5 µmol ammonia, individually applied, represent the IC(50) concentrations that cause negative effects on Arabidopsis thaliana.