Nitroxide radical conjugated ovalbumin theranostic nanosystem for enhanced dendritic cell-based immunotherapy and T1 magnetic resonance imaging.

Melanoma, known for its aggressive metastatic nature, presents a formidable challenge in cancer treatment, where conventional therapies often fall short. This study introduces a pioneering approach utilizing metal-free nanosystem as tumor vaccines, spotlighting their potential in revolutionizing melanoma treatment. This work employed organic nitroxides, specifically 4-carboxy-TEMPO, in combination with chitosan (CS), to create a novel nanocomposite material - the CS-TEMPO-OVA nanovaccines. This composition not only improves biocompatibility and extends blood circulation time of TEMPO but also marks a significant departure from traditional gadolinium-based contrast agents in MRI technology, addressing safety concerns. CS-TEMPO-OVA nanovaccines demonstrate excellent biocompatibility at both the cellular and organoid level. They effectively stimulate bone marrow-derived dendritic cells (BMDCs), which in turn promote the maturation and activation of T cells. This ultimately leads to a strong production of essential cytokines. These nanovaccines serve a dual purpose as both therapeutic and preventive. By inducing an immune response, activating cytotoxic T cells, and promoting macrophage M1 polarization, they effectively inhibit melanoma growth and enhance survival in mouse models. When combined with αPD-1, the CS-TEMPO-OVA nanovaccines significantly bolster the infiltration of cytotoxic T lymphocytes (CTLs) within tumors, sparking a powerful systemic antitumor response that effectively curbs tumor metastasis. The ability of these nanovaccines to control both primary (subcutaneous) and metastatic B16-OVA tumors highlights their remarkable efficacy. Furthermore, the CS-TEMPO-OVA nanovaccine can be administered in vivo via both intravenous and intramuscular routes, both of which effectively enhance the T1 contrast of magnetic resonance imaging in tumor tissue. This study offers invaluable insights into the integrated application of these nanovaccines in both clinical diagnostics and treatment, marking a significant stride in cancer research and patient care.

Clinical pharmacology and tolerability of REC-994, a redox-cycling nitroxide compound, in randomized phase 1 dose-finding studies.

Cerebral cavernous malformation (CCM) has variable clinical symptoms, including potentially fatal hemorrhagic stroke. Treatment options are very limited, presenting a large unmet need. REC-994 (also known as tempol), identified as a potential treatment through an unbiased drug discovery platform, is hypothesized to treat CCMs through a reduction in superoxide, a reactive oxygen species. We investigated the safety, tolerability, and pharmacokinetic profile of REC-994 in healthy volunteers. Single- and multiple-ascending dose (SAD and MAD, respectively) studies were conducted in adult volunteers (ages 18-55). SAD study participants received an oral dose of REC-994 or placebo. MAD study participants were randomized 3:1 to oral doses of REC-994 or matching placebo, once daily for 10 days. Thirty-two healthy volunteers participated in the SAD study and 52 in the MAD study. Systemic exposure increased in proportion to REC-994 dose after single doses of 50-800 mg and after 10 days of dosing over the 16-fold dose range of 50-800 mg. Median Tmax and mean t1/2 were independent of dose in both studies, and the solution formulation was more rapidly absorbed. REC-994 was well tolerated. Treatment-emergent adverse effects across both studies were mild and transient and resolved by the end of the study. REC-994 has a favorable safety profile and was well tolerated in single and multiple doses up to 800 mg with no dose-limiting adverse effects identified. Data support conducting a phase 2 clinical trial in patients with symptomatic CCM.

Safety, Tolerability, and Pharmacokinetics of FAAH Inhibitor BIA 10-2474: A Double-Blind, Randomized, Placebo-Controlled Study in Healthy Volunteers.

This study evaluated the safety, tolerability, pharmacokinetics, and pharmacodynamics of BIA 10-2474, a fatty acid amide hydrolase (FAAH) inhibitor, after first administration to healthy male and female participants. Participants (n = 116) were recruited into this phase I, double-blind, randomized, placebo-controlled, single ascending dose and multiple ascending dose (10-day) study. The primary outcome was the safety and tolerability of BIA 10-2474. Secondary outcomes were pharmacokinetics of BIA 10-2474 and pharmacodynamics, considering plasma concentrations of anandamide and three other fatty acid amides (FAAs) and leukocyte FAAH activity. Single oral doses of 0.25-100 mg and repeated oral doses of 2.5-50 mg were evaluated. BIA 10-2474 was well tolerated up to 100 mg as a single dose and up to 20 mg once daily for 10 days. In the cohort receiving repeated administrations of 50 mg, there were central nervous system adverse events in five of six participants, one with fatal outcome, which led to early termination of the study. BIA 10-2474 showed a linear relationship between dose and area under plasma concentration-time curve (AUC) across the entire dose range and reached steady state within 5-6 days of administration, with an accumulation ratio, based on AUC0-24h , of <2 on Day 10. BIA 10-2474 was rapidly absorbed with a mean terminal elimination half-life of 8-10 hours (Day 10). BIA 10-2474 caused reversible, dose-related increases in plasma FAAs. In conclusion, we propose that these data, as well as the additional data generated since the clinical trial was stopped, do not provide a complete mechanistic explanation for the tragic fatality.

Tempol Alters Urinary Extracellular Vesicle Lipid Content and Release While Reducing Blood Pressure during the Development of Salt-Sensitive Hypertension.

Salt-sensitive hypertension resulting from an increase in blood pressure after high dietary salt intake is associated with an increase in the production of reactive oxygen species (ROS). ROS are known to increase the activity of the epithelial sodium channel (ENaC), and therefore, they have an indirect effect on sodium retention and increasing blood pressure. Extracellular vesicles (EVs) carry various molecules including proteins, microRNAs, and lipids and play a role in intercellular communication and intracellular signaling in health and disease. We investigated changes in EV lipids, urinary electrolytes, osmolality, blood pressure, and expression of renal ENaC and its adaptor protein, MARCKS/MARCKS Like Protein 1 (MLP1) after administration of the antioxidant Tempol in salt-sensitive hypertensive 129Sv mice. Our results show Tempol infusion reduces systolic blood pressure and protein expression of the alpha subunit of ENaC and MARCKS in the kidney cortex of hypertensive 129Sv mice. Our lipidomic data show an enrichment of diacylglycerols and monoacylglycerols and reduction in ceramides, dihydroceramides, and triacylglycerols in urinary EVs from these mice after Tempol treatment. These data will provide insight into our understanding of mechanisms involving strategies aimed to inhibit ROS to alleviate salt-sensitive hypertension.

Nitrite and tempol combination promotes synergic effects and alleviates right ventricular wall stress during acute pulmonary thromboembolism.

INTRODUCTION: The mechanical obstruction and pulmonary vasoconstriction are major determinants of the sudden right ventricular (RV) afterload increases observed during acute pulmonary thromboembolism (APT). Vasodilators and antioxidants agents have been shown to mitigate pulmonary hypertension. We examined whether sodium nitrite and the antioxidant tempol combination could be advantageous in an APT sheep model. METHODS: APT was induced in anesthetized sheep by autologous blood clots (250 mg/kg) into the right atrium. Thirty minutes after APT induction, the animals received a continuous infusion of tempol (1.0 mg/kg/min), increasing sodium nitrite infusion (5, 15, and 50 µmol/kg), or a simultaneous combination of both drugs. Saline was used as a control treatment. Hemodynamic measurements were carried out every 15 min. Also, whole blood nitrite and serum 8-isoprostanes levels were measured. RESULTS: APT induced sustained pulmonary hypertension, increased dp/dtmax, and rate pressure product (RPP). Nitrite or tempol treatments attenuated these increases (P < 0.05). When both drugs were combined, we found a robust reduction in the RV RPP compared with the treatments alone (P < 0.05). The sole nitrite infusion increased blood nitrite concentrations by 35 ± 6 µM (P < 0.05), whereas the nitrite and tempol combination produced higher blood nitrite concentrations by approximately 54 ± 7 µM. Tempol or nitrite infusions, both alone or combined, blunted the increases in 8-isoprostane concentrations observed after APT. CONCLUSIONS: Nitrite and tempol combination protects against APT-induced RV wall stress. The association of both drugs may offer an advantage to treat RV failure during severe APT.

Targeting transcription of MCL-1 sensitizes HER2-amplified breast cancers to HER2 inhibitors.

Human epidermal growth factor receptor 2 gene (HER2) is focally amplified in approximately 20% of breast cancers. HER2 inhibitors alone are not effective, and sensitizing agents will be necessary to move away from a reliance on heavily toxic chemotherapeutics. We recently demonstrated that the efficacy of HER2 inhibitors is mitigated by uniformly low levels of the myeloid cell leukemia 1 (MCL-1) endogenous inhibitor, NOXA. Emerging clinical data have demonstrated that clinically advanced cyclin-dependent kinase (CDK) inhibitors are effective MCL-1 inhibitors in patients, and, importantly, well tolerated. We, therefore, tested whether the CDK inhibitor, dinaciclib, could block MCL-1 in preclinical HER2-amplified breast cancer models and therefore sensitize these cancers to dual HER2/EGFR inhibitors neratinib and lapatinib, as well as to the novel selective HER2 inhibitor tucatinib. Indeed, we found dinaciclib suppresses MCL-1 RNA and is highly effective at sensitizing HER2 inhibitors both in vitro and in vivo. This combination was tolerable in vivo. Mechanistically, liberating the effector BCL-2 protein, BAK, from MCL-1 results in robust apoptosis. Thus, clinically advanced CDK inhibitors may effectively combine with HER2 inhibitors and present a chemotherapy-free therapeutic strategy in HER2-amplified breast cancer, which can be tested immediately in the clinic.

The superoxide scavenger tempol attenuates DNA oxidative injury and spontaneous pain-like behavior in chronic post-cast pain model rats.

The mechanism of severe pain occurring because of physical disuse, such as complex regional pain syndrome Type I, has not been elucidated so far. Therefore, to investigate this mechanism, we have developed a model called a chronic post-cast pain (CPCP) model. Oxidative stress-related factors generated in a fixed limb may be triggers for nociceptive signals due to physical disuse. On the basis of the results of our previous studies, we speculated that oxidative stress-related factors in immobilized hind limbs may also be triggers of nociceptive signals due to physical disuse. In this study, we aimed to clarify whether an oxidative stress-related factor is involved in the induction of nociceptive signals. The time course of oxidative damage in the soleus (slow-twitch fiber) and gastrocnemius (fast-twitch fiber) muscles was evaluated by immunostaining of 8-hydroxy-2'-deoxyguanosine (a marker of oxidative damage in DNA). We also investigated the effects of tempol, a scavenger of superoxide, on oxidative damage in DNA, spontaneous pain-related behaviors (licking and/or biting and flinching), and the activation of spinal dorsal horn neurons (c-Fos). Systemic administration of tempol before cast removal attenuated oxidative damage to DNA in immobilized skeletal muscles, suppressed spontaneous pain-related behavior, and suppressed the activation of spinal dorsal horn neurons. We suggest that superoxide generated in immobilized skeletal muscles after cast removal is one of the peripheral factors that trigger nociceptive signals.

A Phase I Study of Dinaciclib in Combination With MK-2206 in Patients With Advanced Pancreatic Cancer.

The combination of drugs targeting Ral and PI3K/AKT signaling has antitumor efficacy in preclinical models of pancreatic cancer. We combined dinaciclib (small molecule cyclin dependent kinase inhibitor with MK-2206 (Akt inhibitor) in patients with previously treated/metastatic pancreatic cancer. Patients were treated with dinaciclib (6-12 mg/m2 i.v.) and MK-2206 (60-135 mg p.o.) weekly. Tumor biopsies were performed to measure pAKT, pERK, and Ki67 at baseline and after one completed cycle (dose level 2 and beyond). Thirty-nine patients participated in the study. The maximum tolerated doses were dinaciclib 9 mg/m2 and MK-2206 135 mg. Treatment-related grade 3 and 4 toxicities included neutropenia, lymphopenia, anemia, hyperglycemia, hyponatremia, and leukopenia. No objectives responses were observed. Four patients (10%) had stable disease as their best response. At the recommended dose, median survival was 2.2 months. Survival rates at 6 and 12 months were 11% and 5%, respectively. There was a nonsignificant reduction in pAKT composite scores between pretreatment and post-treatment biopsies (mean 0.76 vs. 0.63; P = 0.635). The combination of dinaciclib and MK-2206 was a safe regimen in patients with metastatic pancreatic cancer, although without clinical benefit, possibly due to not attaining biologically effective doses. Given the strong preclinical evidence of Ral and AKT inhibition, further studies with better tolerated agents should be considered.

Mechanistic study of mtROS-JNK-SOD2 signaling in bupivacaine-induced neuron oxidative stress.

Manganese superoxide dismutase (SOD2) is a key enzyme to scavenge free radical superoxide in the mitochondrion. SOD2 deficiency leads to oxidative injury in cells. Bupivacaine, a local anesthetic commonly used in clinic, could induce neurotoxic injury via oxidative stress. The role and the mechanism of SOD2 regulation in bupivacaine-induced oxidative stress remains unclear. Here, bupivacaine was used to treat Sprague-Dawley rats with intrathecal injection and culture human neuroblastoma cells for developing vivo injury model and vitro injury model. The results showed that bupivacaine caused the over-production of mitochondrial reactive oxygen species (mtROS), the activation of C-Jun N-terminal kinase (JNK), and the elevation of SOD2 transcription. Decrease of mtROS with N-acetyl-L-cysteine attenuated the activation of JNK and the increase of SOD2 transcription. Inhibition of JNK signaling with a small interfering RNA (siRNA) or with sp600125 down-regulated the increase of SOD2 transcription. SOD2 gene knock-down exacerbated bupivacaine-induced mtROS generation and neurotoxic injury but had no effect on JNK phosphorylation. Mito-TEMPO (a mitochondria-targeted antioxidant) could protect neuron against bupivacaine-induced toxic injury. Collectively, our results confirm that mtROS stimulates the transcription of SOD2 via activating JNK signaling in bupivacaine-induced oxidative stress. Enhancing antioxidant ability of SOD2 might be crucial in combating bupivacaine-induced neurotoxic injury.

First-in-human dose: current status review for better future perspectives.

AIM: The aim of this article is to understand the pros and cons of various methods involved in first-in-human (FIH) dose calculation and act decisively in dose escalations when calculating the maximum tolerated dose. SUBJECTS AND METHODS: We reviewed early phase clinical trials for methods of FIH dose and dose-escalation steps and discuss them in line with existing guidelines. We also reviewed the clinical trial registry to recognize trends in trial registration in recent years and after a massive failure in a few trials. RESULTS: Phase 1 trials of TGN 1412 and BIA10-2474 would always be remembered as catastrophes for pharmaceutical development plans. Quite often than not, healthy human volunteers are the guinea pigs in this stage of drug development. And, the most important aspect of designing an early phase study is deciding upon the dose to be started with, apart from the selection of cohort and escalation steps. The common principles used for FIH dose calculation include no observed adverse effect level, minimum anticipated biological effect level, pharmacologically active dose, pharmacokinetic/pharmacodynamic approach, and similar drug comparison approach. CONCLUSION: Early phase clinical trials are basically foundation stones on which lies the entire onus of the later stages of development. Deciding FIH dose is a crucial step that necessitates the incorporation of detailed data from the preclinical stages and application of the most conservative approach for the safety/benefit of the volunteers in these studies.

Effect of reactive oxygen species of the psoas major muscle in complete Freund's adjuvant-induced inflammatory pain in rats.

Lower limb pain is a common clinical disease that affects millions of people worldwide. It is found in previous studies that reactive oxygen species is closely related to neuropathic, cancer, chemotherapy, and inflammatory pain, which can be relieved by reactive oxygen species scavengers. Furthermore, acupuncture or electroacupuncture on the psoas major muscle has a great effect on adjuvant-induced arthritis and lower back pain. In our study, we investigated the function of reactive oxygen species scavengers locally injecting into the ipsilateral psoas major muscle on complete Freund's adjuvant-induced inflammatory pain. Our results demonstrated that in the development of complete Freund's adjuvant-induced inflammatory pain, early local continuous application of N-tert-Butyl-α-phenylnitrone (PBN, 1 and 5 mg/kg/0.2 ml) on the ipsilateral psoas major muscle effectively reduced mechanical and cold hyperalgesia. However, intraperitoneal injection of PBN (1 and 5 mg/kg) or local injection of PBN (1 and 5 mg/kg/0.2 ml) into contralateral psoas major muscle, ipsilateral quadratus lumborum, and ipsilateral erector spinae showed limited effect. In the developed inflammatory pain model, local injection of PBN into the ipsilateral psoas major muscle also alleviated pain and paw edema. In addition, reactive oxygen species level increased in ipsilateral psoas major muscle at seven days after complete Freund's adjuvant injection. In general, PBN reduces complete Freund's adjuvant-evoked inflammatory pain by inhibiting reactive oxygen species in the psoas major muscle.

Novel neuroprotection using antioxidant nanoparticles in a mouse model of head trauma.

INTRODUCTION: Free radicals and reactive oxygen species are related to deteriorating pathological conditions after head trauma because of their secondary effects. 2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO) scavenges free radicals; however, this molecule is also toxic. Here, we have evaluated the neuroprotective effect of antioxidant nanoparticles, which consisted of a novel core-shell type nanoparticle containing 4-amino-TEMPO, that is, redox-active nitroxide radical-containing nanoparticles (RNPs). METHODS: Institute of Cancer Research mice were subjected to a head-impact procedure, randomly divided into four groups and intravenously (3 mg/kg) administered phosphate-buffered saline, TEMPO, micelle (a self-assembling block copolymer micelle without a TEMPO moiety), or RNP through the tail vein immediately thereafter and intraperitoneally at days 1, 3, and 5 after traumatic brain injury (TBI). The RNP distribution was detected by rhodamine labeling. Cognitive behavior was assessed using the neurological severity score and a rotarod test at days 1, 3, and 7 following TBI, and contusion volume was measured at day 7 after TBI. Free radical-scavenging capacity was analyzed by electron paramagnetic resonance on day 1 after TBI, and immunostaining was used to observe mobilization of microglia (Iba-1) and rescued neuronal cells (NeuN). RESULTS: Redox-active nitroxide radical-containing nanoparticle was detected in the microvessels around the injured area in the brain. Cognitive behavior assessment was significantly better, and contusion volume was significantly smaller in the RNP group compared with the other groups. Superoxide anion scavenging capacity was significantly higher in the RNP group, and neuronal loss was significantly suppressed around the injured area at day 7 after TBI. Furthermore, in the RNP group, neurodegenerative microglia production was suppressed at days 3 and 7 after TBI, whereas neuroprotective microglia production was higher at day 7 after TBI. CONCLUSION: The RNP administration after TBI improved cognitive behavior and reduced contusion volume by improving reactive oxygen species scavenging capacity. Therefore, RNP may have a neuroprotective effect after TBI. LEVEL OF EVIDENCE: Therapeutic test.

Regulatory safety pharmacology evaluation of BIA 10-2474.

The present paper describes the regulatory safety pharmacology studies that were carried out to support the clinical trial application for BIA 10-2474. Animal studies complied with worldwide regulatory guidelines (e.g. EEC Council Directive 75/318/EEC and subsequent amendments). Oral administration of BIA 10-2474 at doses of 30, 100 and 300 mg/kg to male Han Wistar rats did not cause any significant physiological or behavioral changes, affect the respiration rate or the tidal volume, the gastrointestinal transit, urinary output volume or pH, nor urinary sodium, potassium or chloride excretion. BIA 10-2474, at 30 µg/mL, slightly, but significantly, reduced the hERG outward tail currents by 10.62%, but had no effect at 1, 3 or 10 µg/mL. BIA 10-2474 (1.5, 4.5 and 15 µg/mL) had no substantial effects on resting membrane potential (RMP), maximal upstroke velocity (Vmax), action potential amplitude (APA), action potential duration at 30%, 60% and 90% or action potential triangulation over the 30-min superfusion period in the dog isolated Purkinje fiber. In conscious dogs monitored by telemetry, BIA 10-2474 (20, 50 and 100 mg/kg p.o.) did not significantly modify arterial blood pressure as compared with controls (inter-group comparison), although a tendency toward an increase in arterial blood pressure was observed at 100 mg/kg, with systolic blood pressure being the most affected parameter. In conclusion, BIA 10-2474 had no adverse effects on any of the major vital organ systems, and, unfortunately, the data shed no further light on the mechanism(s) responsible for the clinical trial accident with BIA 10-2474.

Hernia Repair Strength Enhanced With Antioxidants.

BACKGROUND: Incisional hernia is one of the most common complications of abdominal surgery, and repairs are associated with significant recurrence rates. Mesh repairs are associated with the best outcomes, but failures are not uncommon. Doxycycline has been demonstrated to enhance mesh hernia repair outcomes with associated increases in collagen deposition and improved tensiometric strength. This study compares the outcomes of incisional hernia repair with doxycycline administration and the antioxidant tempol. MATERIALS AND METHODS: Twenty-eight male Sprague Dawley rats underwent a midline hernia creation and an intraabdominal polypropylene mesh repair. The animals were administered saline, doxycycline, tempol, or both, daily for 8 wk. The abdominal wall was harvested at 8 wk and tensiometric strength and biochemical analysis was performed. RESULTS: The tensiometric strength of the repair was increased in all experimental groups. Collagen type 1 deposition was increased, and collagen type 3 deposition was decreased in each of the experimental groups relative to control. There was no difference in MMP-2 and MMP-9 levels between control and experimental groups. CONCLUSIONS: The hernia repair strength is equally enhanced with the administration of doxycycline or tempol. Dual therapy provided no benefit over treatment with either single agent. All treatment groups had an increase in collagen type 1:3 ratios, but the mechanism is not well understood. The benefits of antioxidant treatment following hernia repair are similar to treatment with doxycycline. Given the high frequency of incisional hernia repair failures, this study has implications for improving outcomes following ventral hernia repair through the use of either doxycycline or antioxidant therapy.

Oral repeated-dose toxicity studies of BIA 10-2474 in CD-1 mice.

We independently and retrospectively reviewed three studies that evaluated the toxicity of BIA 10-2474 (3-(1-(cyclohexyl(methyl)carbamoyl)-lH-imidazol-4-yl)pyridine 1-oxide), a novel fatty acid amide hydrolase (FAAH) inhibitor in male and female CD-1 mice based upon raw data obtained from Bial Portela & Companhia S.A. (São Mamede do Coronado, Portugal). These studies were carried out prior to the clinical trial with BIA 10-2474 and formed part of the regulatory submission. An initial oral dose range-finding study with BIA 10-2474 showed that doses from 600 mg/kg/day were poorly tolerated with a high mortality rate and signs of weakness, prostration, labored breathing, clear lacrimation, tachypnea/bradypnea and decreased activity. At lower doses (100 and 300 mg/kg/day) there were few signs but post-mortem analysis showed increased liver weight. In a 28-day study a third of the animals receiving 500 mg/kg/day died or required euthanasia, with similar signs to those seen in the dose-range finding study. At lower doses (i.e. 100 and 300 mg/kg/day) there were few clinical signs although there were dose-related decreases in erythrocyte count and hemoglobin. Histopathology was seen in the 300 and 500 mg/kg/day groups and included hepatocellular hypertrophy (with increased liver weight), nephropathy and enterocyte vacuolation. Finally, in the 13-week oral gavage study, BIA 10-2474 was administered to CD-1 mice of both sexes at dose levels of 25, 75 and 150 mg/kg/day. Under these conditions, there were almost no clinical signs apart from a tendency to increase body-weight. Cholesterol was increased at 75 and 150 mg/kg and remained high after recovery. Liver and spleen weights increased at 75 and 150 mg/kg/day. Histopathologically, there was a dose-dependent increase in sciatic nerve and myofiber degeneration, hepatocellular hypertrophy, nephropathy and inflammatory loci in the bladder. The nerve damage and nephropathy seen at 150 mg/kg/day persisted after a 4-week recovery period. Toxicokinetic analysis in the 4- and 13-week studies showed that exposure was broadly dose-proportional with no evidence of accumulation. On the basis of the changes seen during the 13-week study, the NOAEL was established at 75 mg/kg/day.

Oral repeated-dose toxicity studies of BIA 10-2474 in beagle dogs.

BIA 10-2474 is a novel fatty acid amide hydrolase inhibitor developed for the treatment of medical conditions which would benefit from enhanced levels of endogenous anandamide (AEA) such as pain disorders. During a Phase I clinical trial one subject died after receiving BIA 10-2474 and others displayed neurological signs. We describe here the toxicology studies in beagle dogs that supported phase I testing of BIA 10-2474 in humans. A Maximum Tolerated Dose (MTD) study using once-a-day oral (capsule) application of BIA 10-2474 was first conducted to establish suitable dose levels for subsequent studies. Based on these results, 100 mg/kg/day was considered to be the MTD. The 4-week oral (capsule) toxicity study with a 3-week recovery period for BIA 10-2474 was therefore carried out at 20, 50 or 100 mg/kg/day. There were no changes recorded at 50 mg/kg/day and this was considered the oral No Observed Effect Level (NOEL) for four-week once-a-day capsule administration to Beagle dogs. At 100 mg/kg/day, the dose-limiting findings consisted of clinical symptoms including tremor, loss of balance, abnormal gait, decreased motor activity, weakness, vomits, salivation increase and miosis, increased severity of thymic atrophy/involution, and moderate acute, focal/multifocal bronchopneumonia in lungs of three animals. In a 13-week oral (capsule) toxicity study in the Beagle dog with a 6-week recovery period, using the same dose levels, clinical signs were recorded during treatment with BIA 10-274 at 50 and 100 mg/kg/day. The most frequent signs included difficulty breathing, respiratory sounds (with or without auscultation) and cough. Incoordination of the hind limbs with absence of correction reflex were also observed on some occasions. As a result, the 50 and 100 mg/kg/day doses were reduced to 35 and 50 mg/kg/day respectively on day 37. Because of the continued signs, the doses in both groups were further reduced to 20 mg/kg/day from day 77. Under the conditions of this study and given the severe signs recorded in groups treated at 100-50-20 and 50-35-20 mg/kg/day and only very occasional presence of signs in the group treated for the 13-week period at 20 mg/kg/day (abnormal respiratory sounds once in two animals), the dose of 20 mg/kg/day was considered the No Observed Adverse Effect Level (NOAEL).

Oral repeated-dose toxicity studies of BIA 10-2474 in cynomolgus monkeys.

BIA 10-2474 (3-(1-(cyclohexyl(methyl)carbamoyl)-1H-imidazol-4-yl)pyridine 1-oxide) is a novel fatty acid amide hydrolase (FAAH) inhibitor developed by BIAL for the treatment of medical conditions which would benefit from enhanced levels of endogenous anandamide (AEA) such as pain disorders. During a Phase I clinical trial one subject died after receiving BIA 10-2474 and others displayed neurological signs. As part of series of papers presenting all the toxicology data available prior to the clinical trial we report here the nonclinical toxicology studies performed in cynomolgus monkeys. Maximum Tolerated Dose (MTD) studies and a preliminary 14-day study by oral (capsule) administration of BIA 10-2474 established a dose between 90 and 120 mg/kg/day as a suitable high dose for a subsequent regulatory toxicity studies. An up-titration scheme was used to achieve these doses. The dose-limiting effect was the early sacrifice for ethical reasons of monkeys at doses from 125 mg/kg/day upwards. Thereafter, regulatory 4- and 13-week oral gavage toxicity studies followed by a 2- or a 4-week recovery period, respectively, were performed. In both cases a 3-4-week up-titration period was used prior to repeat dosing with the target doses. One female was euthanized during the up-titration period after receiving 9 administrations of 75 mg/kg as a result of bleeding erosion on the feet and hands and ulceration on the tongue. These signs were not seen in any other monkeys during these studies. Doses of 10, 50 or 100 mg/kg/day were administered during the 4-week study and clinical signs related to the pharmacological action of BIA 10-2474 (e.g., tremors and weakness, incoordination and loss of balance, reduction in food intake and reduced body weight) were observed in several monkeys from the intermediate and high dose. Histological alterations consisted of axonal dystrophy in the fasciculus cuneatus (dorsal medulla oblongata) characterized by swollen axons and myelin sheath edema, edema in the pars nervosa of the pituitary gland and vacuolation of Meissner's plexus ganglia in all gastrointestinal segments. All lesions recovered and a dose of 100 mg/kg/day was considered to be the NOAEL. In the 13-week oral study the monkeys received BIA 10-2474 daily by gavage at a dose of 6.25, 37.5 or 75 mg/kg/day. Similar clinical signs and histological alterations as noted in monkeys of the 28-day study were observed in monkeys at 37.5 or 75 mg/kg/day. All findings recovered, and the dose of 75 mg/kg/day was considered the NOAEL.

Developmental and reproductive toxicity studies of BIA 10-2474.

A series of regulatory studies were carried out to investigate the effects of the FAAH inhibitor BIA 10-2474 on fertility, embryo-fetal toxicity and pre- and post-natal development in rats and rabbits. Despite some reductions in sperm count in rats from 50 mg/kg, there were no major changes in male fertility up to 100 mg/kg. In female rats administered up to GD6, there were increases in pre-implantation loss at 50 and 100 mg/kg but neither post-implantation loss nor early embryonic development was affected. In contrast, when administered to female rats during pregnancy (GD6-GD17), BIA 10-2474 at 75 mg/kg/day reduced food consumption resulting in weight loss, increased post-implantation loss and reduced mean fetal body weight. In rabbits, the same maternal toxicity was seen but there were no effects in this species on post-implantation loss or fetal body weights. There were no teratological effects clearly due to BIA 10-2474 and developmental milestones and behavior of offspring were not affected. When administered during pregnancy and lactation (GD6-PND20), some post-implantation loss was seen from 20 mg/kg/day, but developmental milestones and behavior of the offspring were not affected, although males tended to have lower body weight. Based on these data the NOAEL for parental fertility was established as 50 mg/kg/day, the maternal NOAEL during pregnancy was 25 mg/kg/day in rats and developmental NOAEL was 25 and 75 mg/kg/day in rats and rabbits, respectively. When administered during post-natal development to rats the maternal NOAEL was 6 mg/kg/day. The parental reproductive NOAEL, the NOAEL for viability and growth of the F1 offspring, the F1 parental NOAEL and the F1 reproductive NOAEL were all considered to be 20 mg/kg/day.

Oral repeated-dose toxicity studies of BIA 10-2474 in Wistar rat.

BIA 10-2474 is a novel fatty acid amide hydrolase (FAAH) inhibitor developed for the treatment of medical conditions which would benefit from enhanced levels of endogenous anandamide (AEA) such as pain disorders. During a Phase I clinical trial one subject died after receiving BIA 10-2474 and four other subjects displayed neurological signs. As part of series of papers presenting all the toxicology data available prior to the clinical trial, we report here the preclinical toxicology studies examining once-a-day oral administration of BIA 10-2474 to male and female Wistar rats. These included a 14-day dose range finding (150, 200 and 250 mg/kg/day), a 4-week study (30, 90 and 150 mg/kg/day) and 13- and 26-week studies (both at 10, 30 and 90 mg/kg/day). The 13- and 26-week studies also included a 4-week recovery arm and a toxicokinetic arm for the parent compound, BIA 10-2474, and the two major metabolites (BIA 10-2445 and BIA 10-2583) were also measured in the 26-week study. At 150 mg/kg and below, all animals survived the scheduled treatment periods although neurological side-effects (abnormal or stiff gait, dragging of fore- or hind-limbs) were seen at 150 mg/kg in both the dose-range finding and 4-week studies. At 90 mg/kg/day, even up to 26-weeks treatment, no clinical signs were seen apart from some decreases in body weight gain. A number of consistent hematological and biochemical changes were noted which were considered related to treatment with BIA 10-2474. Morphologically, in the 4-week study, except for a slight gliosis in the hippocampus of one female at 150 mg/kg, no CNS histopathology was observed; hippocampus gliosis was not observed in subsequent studies. In the 13-week study axonal swelling was present in the medulla oblongata in about half the animals at 90 mg/kg/day and this increased to nearly all the rats at 90 mg/kg/day in the 26-week study. Additional signs seen only in the 26-week study at 90 mg/kg/day included axonal swelling of the fasiculus gracilis and vacuolar changes in the medulla oblongata and ventral commissure of the 3rd ventricle. Other findings included vacuolar degeneration in the ganglia of the GI tract, salivary glands, prostate gland, uterus, and parathyroid glands. The pituitary gland showed edema and mitotic figures in the pars nervosa. These observations outside the CNS were seen in most rats at 90 and 150 mg/kg/day independent of study duration. At 30 mg/kg/day, most of these observations were only seen in isolated cases except for the vacuolar degeneration in GI tract ganglia, which was absent at this dose after 4 weeks treatment but was present in almost all rats at 13 and 26 weeks. Hepatocellular hypertrophy and nephropathy were seen across all studies and the extent of these changes was similar in the 13- and 26-week studies. Most findings resolved after the 4-week recovery periods except for the axonal swelling seen in the medulla oblongata and spinal cord. BIA 10-2474 exposure was markedly higher than the exposure to either metabolite, BIA 10-2445 (19- to 192-fold) and BIA 10-2583 (63- to 526-fold). Exposure to metabolites differed between sexes with higher concentrations of BIA 10-2445 in females compared to males, but the inverse for BIA 10-2583. Although a No Observed Adverse Effect Level (NOAEL) of 30 mg/kg/day was concluded following the 4-week study, the histopathological findings at that dose in the 13- and 26-week studies resulted in the NOAEL being determined to be 10 mg/kg/day.

Effect of Tempol, a Membrane-Permeable Free Radical Scavenger, on In Vitro Model of Eye Inflammation on Rabbit Corneal Cells.

Purpose: Inflammatory corneal diseases such as bacterial keratitis provoke severe injury to the visual functions and physical structure, leading to opaqueness, wounding, damage to the cornea, and even long-lasting vision loss. Usually antioxidant substances have been of great attention as candidate therapies in the management of keratitis in both humans and animals. Based on the findings, the aim of our research was to examine the effects of Tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl), a membrane-permeable free radical scavenger with exclusive antioxidant properties, on in vitro model of eye inflammation of rabbit corneal cells stimulated with lipopolysaccharide (LPS) (Seruminstitute Rabbit Cornea). Methods: The cells were pretreated with Tempol and incubated with LPS for 24 h. LPS stimulation triggered increased cellular mortality, oxidative stress, cytokine levels expression of tumor necrosis factor (TNF)-α, interleukin (IL)-1ß and IL-6, and also enhanced prostaglandin E2 (PGE2) levels and cyclooxygenase-2 (COX-2) expression. Results: Pretreatment with Tempol (3 mM) significantly increased cell viability and antioxidant activity as well as decreased reactive oxygen species production, cytokines, PGE2 levels, and COX-2 expression. Conclusions: Taken together, Tempol could be a new therapeutic strategy for management of ocular inflammatory disorders for clinical and veterinary use.