Neurofibromatosis type 1-associated optic pathway gliomas: pathogenesis and emerging treatments.

Neurofibromatosis type 1 (NF1) is an autosomal dominant genetic disorder associated with an increased risk of developing a variety of benign and malignant tumors. Fifteen to 20% of children with NF1 are diagnosed with an optic pathway glioma (NF1-OPG) before 7 years of age, and more than half of them experience visual decline. At present, no effective therapy is available for prevention, restoration, or even stabilization of vision loss in subjects affected by NF1-OPG. This paper aims to review the main emerging pharmacological approaches that have been recently assessed in preclinical and clinical settings. We performed a search of the literature using Embase, PubMed, and Scopus databases to identify articles regarding NF1-OPGs and their treatment up to July 1st, 2022. The reference lists of the analyzed articles were also considered a source of literature information. To search and analyze all relevant English articles, the following keywords were used in various combinations: neurofibromatosis type 1, optic pathway glioma, chemotherapy, precision medicine, MEK inhibitors, VEGF, nerve growth factor. Over the past decade, basic research and the development of genetically engineered mice models of NF1-associated OPG have shed light on the cellular and molecular mechanisms underlying the disease and inspired animal and human testing of several compounds. A promising line of research is focusing on the inhibition of mTOR, a protein kinase controlling proliferation, protein synthesis rate and cell motility that is highly expressed in neoplastic cells. Several mTOR blockers have been tested in clinical trials, the most recent of which employed oral everolimus with encouraging results. A different strategy aims at restoring cAMP levels in neoplastic astrocytes and non-neoplastic neurons, since reduced intracellular cAMP levels contribute to OPG growth and, more importantly, are the major determinant of NF1-OPG-associated visual decline. So far, however, this approach has only been attempted in preclinical studies. Stroma-directed molecular therapies - seeking to target Nf1 heterozygous brain microglia and retinal ganglion cells (RGCs) - are another fascinating field. Microglia-inhibiting strategies have not yet reached clinical trials, but preclinical studies conducted over the last 15 years have provided convincing clues of their potential. The importance of NF1-mutant RGCs in the formation and progression of OPGs also holds promise for clinical translation. The evidence of Vascular Endothelial Growth Factor (VEGF)- Vascular Endothelial Growth Factor (VEGFR) signaling hyperactivity in pediatric low-grade gliomas prompted the use of bevacizumab, an anti-VEGF monoclonal antibody, which was tested in children with low-grade gliomas or OPGs with good clinical results. Neuroprotective agents have also been proposed to preserve and restore RGCs and topical eye administration of nerve growth factor (NGF) has demonstrated encouraging electrophysiological and clinical results in a double-blind, placebo-controlled study. Traditional chemotherapy in patients with NF1-OPGs does not significantly ameliorate visual function, and its effectiveness in halting tumor growth cannot be considered a satisfactory result. Newer lines of research should be pursued with the goal of stabilizing or improving the vision, rather than reducing tumor volume. The growing understanding of the unique cellular and molecular characteristics of NF1-OPG, coupled with the recent publication of promising clinical studies, raise hope for a shift towards precision medicine and targeted therapies as a first-line treatment.

Effects of Topical Application of CHF6467, a Mutated Form of Human Nerve Growth Factor, on Skin Wound Healing in Diabetic Mice.

Nerve growth factor (NGF) is the protein responsible for the development and maintenance of sensory skin innervation. Given the role of appropriate innervation in skin healing, NGF has been indicated as a possible prohealing treatment in pathologic conditions characterized by nerve-ending loss, such as chronic ulcers in diabetes; however, its use as a therapeutic agent is limited by its hyperalgesic effect. We tested the effect of topical application of the nonalgogenic NGF derivative hNGFP61S/R100E in two models of skin ulcer induced in dbdb diabetic mice, investigating healing time, skin histology, reinnervation, and angiogenesis using morphologic and molecular approaches. We showed that the topical administration of CHF6467, a recombinant human NGF in which an amino acid substitution (R100E) abolished the hyperalgesic effect usually associated with NGF, accelerated skin repair in experimental wounds (full-excision and pressure-ulcer) induced in diabetic mice (dbdb). CHF6467-induced acceleration of wound healing was accompanied by increased re-epithelization, reinnervation, and revascularization as assessed by histology, immunohistochemistry, and image analysis. Bioinformatic analysis of differentially expressed genes and signaling pathways in the wound tissues showed that protein kinase B-mammalian target of rapamycin was the most regulated pathway. In spite of the transdermal absorption leading to measurable, dose-dependent increases in CHF6467 plasma levels, no systemic thermal or local mechanical hyperalgesia was observed in treated mice. When tested in vitro in human cell lines, CHF6467 stimulated keratinocyte and fibroblast proliferation and tube formation by endothelial cells. Collectively, these results support a possible use of CHF6467 as a prohealing agent in skin lesions in diabetes. SIGNIFICANCE STATEMENT: Topical application of CHF6467 accelerates reinnervation, neoangiogenesis, and wound healing in diabetic mice in both full-thickness skin-excision and pressure-ulcer models through the protein kinase B/mammalian target of rapamycin pathway and does not induce hyperalgesia.

CHF5074 (CSP-1103) induces microglia alternative activation in plaque-free Tg2576 mice and primary glial cultures exposed to beta-amyloid.

Activation of microglia associated with neuroinflammation and loss of phagocytic activity is considered to play a prominent role in the pathogenesis of Alzheimer's disease (AD). CHF5074 (CSP-1103) has been shown to improve cognition and reduce brain inflammation in patients with mild cognitive impairment (MCI). CHF5074 was also found to reverse impairments in recognition memory and improve hippocampal long-term potentiation when administered to plaque-free Tg2576 mice (5-month-old) for 4 weeks. Though, no investigation has focused on the consequence of CHF5074 treatment on microglia polarization yet. In this study we evaluated the effect of CHF5074 administration (375 ppm in the diet) to 5-month-old Tg2576 mice on the expression of pro-inflammatory (M1) genes, Interleukin 1 beta (IL-1ß), Tumor Necrosis Factor alpha (TNFα) and inducible Nitric Oxide Synthase (iNOS), and anti-inflammatory/phagocytic (M2) markers Mannose Receptor type C 1 (MRC1/CD206), Triggering Receptor Expressed on Myeloid cells 2 (TREM2) and Chitinase 3-like 3 (Ym1). No changes of pro-inflammatory gene transcription but a reduced expression of MRC1/CD206, TREM2 and Ym1 were detected in the hippocampus of young Tg2576 mice receiving normal diet, when compared to wild-type littermates. CHF5074 did not affect the pro-inflammatory transcription but significantly increased the expression of MRC1/CD206 and Ym1. CHF5074 effects appeared to be hippocampus-specific, as the M2 transcripts were only slightly modified in the cerebral cortex. In primary cultures of mouse astrocyte-microglia, CHF5074 totally suppressed the expression of TNF-α, IL-1ß and iNOS induced by 10 µM ß-amyloid1-42 (Aß42). Moreover, CHF5074 significantly increased the expression of anti-inflammatory/phagocytic markers MRC1/CD206 and TREM2, reduced by the Aß42 application alone. The effect of CHF5074 was not reproduced by ibuprofen (3 µM or 500 µM) or R-flurbiprofen (3 µM or 100 µM), as both compounds limited the pro-inflammatory gene expression but did not modify the anti-inflammatory/phagocytic transcription. These data show that CHF5074 specifically drives the expression of microglia M2 markers either in young Tg2576 hippocampus or in primary astrocyte-microglia cultures, suggesting its potential therapeutic efficacy as microglial modulator in the early phase of AD.

Electrophysiological and metabolic effects of CHF5074 in the hippocampus: protection against in vitro ischemia.

CHF5074 is a non-steroidal anti-inflammatory derivative holding disease-modifying potential for the treatment of Alzheimer's disease. The aim of the present study was to characterize the electrophysiological and metabolic profile of CHF5074 in the hippocampus. Electrophysiological recordings show that CHF5074 inhibits in a dose-dependent manner the current-evoked repetitive firing discharge in CA1 pyramidal neurons. This result is paralleled by a dose-dependent reduction of field excitatory post-synaptic potentials with no effect on the paired-pulse ratio. The effects of CHF5074 were not mediated by AMPA or NMDA receptors, since the inward currents induced by local applications of AMPA and NMDA remained constant in the presence of this compound. We also suggest a possible activity of CHF5074 on ASIC1a receptor since ASIC1a-mediated current, evoked by application of a pH 5.5 solution, is reduced by pretreatment with this compound. Moreover, we demonstrate that CHF5074 treatment is able to counteract in hippocampal slices the OGD-induced increase in alanine, lactate and acetate levels. Finally, CHF5074 significantly reduced the apoptosis in hippocampal neurons exposed to OGD, as revealed by cleaved-caspase-3 immunoreactivity and TUNEL staining. Overall, the present work identifies novel mechanisms for CHF5074 in reducing metabolic acidosis, rendering this compound potentially useful also in conditions of brain ischemia.

CHF5074 and LY450139 sub-acute treatments differently affect cortical extracellular glutamate levels in pre-plaque Tg2576 mice.

CHF5074 is a nonsteroidal anti-inflammatory derivative that has been shown to inhibit ß-amyloid plaque deposition and to reverse memory deficit in vivo in transgenic mouse models of Alzheimer's disease (AD). In the present in vivo study we used pre-plaque Tg2576 mice showing cognitive impairments to investigate the effects of a sub-acute treatment with CHF5074 on prefrontal cortex dialysate glutamate levels. Furthermore, the effects of CHF5074 have been compared with those induced, under the same experimental conditions, by LY450139, a potent γ-secretase inhibitor, that has been shown to inhibit brain ß-amyloid production. No differences in prefrontal cortex dialysate glutamate levels were observed between control Tg2576 and wild-type animals. A sub-acute (8days) treatment with CHF5074 (30mg/kg, s.c.), LY450139 (3mg/kg, s.c.) or their respective vehicles did not modify prefrontal cortex dialysate glutamate levels. After these treatments, the injection of CHF5074 reduced, while LY450139 increased, prefrontal cortex dialysate glutamate levels in Tg2576 mice, but not in wild-type animals. These results suggest that at the dose tested CHF5074 and LY450139 differently affect cortical glutamate transmission in pre-plaque Tg2576 mice. This different neurochemical profile could be involved in the different ability of the two drugs in improving early cognitive performance in this animal model of AD.

Interacting with γ-secretase for treating Alzheimer's disease: from inhibition to modulation.

Drugs currently used for the treatment of Alzheimer's disease (AD) produce limited clinical benefits, and there is no disease-modifying therapy yet available. Compounds that inhibit or modulate γ-secretase, the pivotal enzyme that generates ß-amyloid (Aß), are potential therapeutics for AD. This article briefly reviews the profile of γ-secretase inhibitors and modulators that have reached the clinic. Studies in both transgenic and non-transgenic animal models of AD have indicated that γ-secretase inhibitors, administered by the oral route, are able to lower brain Aß concentrations. However, scanty data are available on the effects of these compounds on brain Aß deposition after prolonged administration. γ-Secretase inhibitors may cause abnormalities in the gastrointestinal tract, thymus, spleen, skin, and decrease in lymphocytes and alterations in hair color in experimental animals and in man, effects believed to be associated with the inhibition of the cleavage of Notch, a transmembrane receptor involved in regulating cell-fate decisions. Unfortunately, two large Phase III clinical trials of semagacestat in mild-to-moderate AD patients were prematurely interrupted because of the observation of a detrimental cognitive and functional effect of the drug. These detrimental effects were mainly ascribed to the inhibition of the processing of an unknown substrate of γ-secretase. It has been also hypothesized that the detrimental cognitive effects observed after semagacestat administration are due to the accumulation of the neurotoxic precursor of Aß (the carboxy-terminal fragment of amyloid precursor protein, APP, or CTFß) resulting from the block of the γ-secretase cleavage activity on APP. Some non-steroidal anti-inflammatory drugs and other small organic molecules have been found to modulate γ-secretase shifting its cleavage activity from longer to shorter Aß species without affecting Notch cleavage. However, two large Phase III studies in mild AD patients with tarenflurbil, a putative γ-secretase modulator, were also completely negative. The failure of tarenflurbil was ascribed to low potency and brain penetration. New more selective γ-secretase inhibitors and more potent, more brain penetrant γ-secretase modulators are being developed with the hope of overcoming the previous setbacks. Further understanding of the reasons of the failures of these γ-secretase-based drugs in AD may be important for the future research on effective treatments for this devastating disease.

Mediterranean diet in predementia and dementia syndromes.

There is a critical need to potentially individualize new strategies able to prevent and to slow down the progression of predementia and dementia syndromes. Only recently higher adherence to a Mediterranean-type diet was associated with decreased cognitive decline although the Mediterranean diet (MeDi) combines several foods, micro- and macronutrients already separately proposed as potential protective factors against dementia and predementia syndromes. In fact, elevated saturated fatty acids could have negative effects on age-related cognitive decline and mild cognitive impairment (MCI). Furthermore, at present, epidemiological evidence suggested a possible association among fish consumption, monounsaturated fatty acids and polyunsaturated fatty acids (PUFA) (particularly, n-3 PUFA) and reduced risk of cognitive decline and dementia. Light to moderate alcohol use may be associated with a reduced risk of incident dementia and Alzheimer's disease (AD), while for vascular dementia, cognitive decline, and predementia syndromes the current evidence is only suggestive of a protective effect. Finally, the limited epidemiological evidence available on fruit and vegetable consumption and cognition generally supported a protective role of these macronutrients against cognitive decline, dementia, and AD. Moreover, recent prospective studies provided evidence that higher adherence to a Mediterranean-type diet could be associated with slower cognitive decline, reduced risk of progression from MCI to AD, reduced risk of AD, and decreased all-causes mortality in AD patients. These findings suggested that adherence to the MeDi may affect not only the risk for AD, but also for predementia syndromes and their progression to overt dementia. Nonetheless, at present, no definitive dietary recommendations are possible. However, high levels of consumption of fats from fish, vegetable oils, non-starchy vegetables, low glycemic fruits, and diet low in foods with added sugars and with moderate wine intake should be encouraged. In fact, this dietary advice is in accordance with recommendations for lowering the risk of cardiovascular disease, obesity, diabetes, and hypertension and might open new ways for the prevention and management of cognitive decline and dementia.

Metabolic syndrome, mild cognitive impairment, and dementia.

At present, the search for preventive strategies for cognitive decline and dementia appears to be of crucial importance, given that the therapeutic options currently available have demonstrated limited efficacy. Cumulative epidemiological evidence suggested that vascular and vascular-related factors may be important for the development of age-related cognitive decline (ARCD), mild cognitive impairment (MCI), and cognitive decline of degenerative (Alzheimer's disease, AD) or vascular origin (vascular dementia, VaD). Among vascular-related factors, metabolic syndrome (MetS) has been associated with the reduced risk of predementia syndromes (ARCD and MCI), overall dementia, and VaD, but contrasting findings also exist on the possible role of MetS in AD. In the next future, trials could then be undertaken to determine if modifications of these risks including inflammation, another factor probably related to MetS, could lower risk of developing cognitive decline. If MetS is associated with increased risk of developing cognitive impairment, then early identification and treatment of these individuals at risk might offer new avenues for disease course modification. Future research aimed at identifying mechanisms that underlie comorbid associations will not only provide important insights into the causes and interdependencies of predementia and dementia syndromes, but will also inspire novel strategies for treating and preventing these disorders. At present, vascular risk factor management could be decisive in delaying the onset of dementia syndromes or in preventing the progression of predementia syndromes.

CHF5074, a novel gamma-secretase modulator, attenuates brain beta-amyloid pathology and learning deficit in a mouse model of Alzheimer's disease.

BACKGROUND AND PURPOSE: We evaluated the effects of 1-(3',4'-dichloro-2-fluoro[1,1'-biphenyl]-4-yl)-cyclopropanecarboxylic acid (CHF5074), a new gamma-secretase modulator, on brain beta-amyloid pathology and spatial memory in transgenic mice expressing the Swedish and London mutations of human amyloid precursor protein (hAPP). EXPERIMENTAL APPROACH: Sixty 6-month-old hAPP mice were treated for 6 months with CHF5074 or ibuprofen (375 ppm in the diet) or standard diet. Twenty-one wild-type mice received standard diet. KEY RESULTS: Compared with transgenic controls, CHF5074 treatment significantly reduced the area occupied by plaques in cortex (P = 0.003) and hippocampus (P = 0.004). The number of plaques were also reduced by CHF5074 in both cortex (P = 0.022) and hippocampus (P = 0.005). Plaque-associated microglia in CHF5074-treated animals was lower than in transgenic controls in cortex (P = 0.008) and hippocampus (P = 0.002). Ibuprofen treatment significantly reduced microglia area in cortex and hippocampus but not beta-amyloid burden. On the last day of the Morris water maze, transgenic controls performed significantly worse than the non-transgenic animals and the CHF5074-treated transgenic mice, on the swimming path to reach the hidden platform. Ibuprofen-treated animals did not perform significantly better than transgenic controls. CONCLUSIONS AND IMPLICATIONS: Chronic CHF5074 treatment reduced brain beta-amyloid burden, associated microglia inflammation and attenuated spatial memory deficit in hAPP mice. This novel gamma-secretase modulator is a promising therapeutic agent for Alzheimer's disease.

Pharmacodynamic-tolerability relationships of cholinesterase inhibitors for Alzheimer's disease.

According to the cholinergic hypothesis, the impairment of cognitive function and the behavioural disturbances that affect patients with Alzheimer's disease are mainly due to cortical deficiencies in cholinergic transmission. Numerous cholinesterase inhibitors have been investigated for treatment of this disease, the rationale being to support the cholinergic system by blocking the degradation of acetylcholine released from presynaptic neurons. These drugs can be classified as reversible (tacrine, donepezil and galantamine), pseudo-reversible (physostigmine, eptastigmine and rivastigmine) or irreversible (metrifonate) enzyme inhibitors. This article reviews efficacy and tolerability results from 6-month placebo-controlled studies of 7 cholinesterase inhibitors: tacrine (80 to 160 mg/day), donepezil (5 to 10 mg/day), rivastigmine (1 to 12 mg/day), metrifonate (30 to 80 mg/day), eptastigmine (30 to 60 mg/day), physostigmine (30 to 36 mg/day) and galantamine (8 to 32 mg/day). All these agents have demonstrated a statistically significant, although modest, effect versus placebo on the cognitive and global performance of patients with Alzheimer's disease. Dramatic clinical response has been seen in only 3 to 5% of patients. There are no major differences in terms of efficacy between the different drugs. The mean difference between drug and placebo effects on standardised psychometric scales is about 2 to 4 points on the cognitive subscale of the Alzheimer's Disease Assessment Scale (ADAS-Cog; a 70-point cognitive scale) and 0.2 to 0.5 points on the Clinician's Interview-Based Impression of Change with Caregiver Input (CIBIC-Plus; a 7-point global scale), or 5 to 14% of the average value of the scales. The most common adverse effects observed after administration of cholinesterase inhibitors are nausea, vomiting, diarrhoea, dizziness, asthenia and anorexia, all symptoms linked to cholinergic overstimulation. These effects are dose related and largely depend on the degree of cholinesterase inhibition. Also important is the rate of onset of cholinesterase inhibition, which depends on the kinetics of enzyme inhibition, the presence and rate of titration, and the pharmacodynamic peak-to-trough fluctuations. A model predicting the incidence of nausea based on acetylcholinesterase inhibition and the half-life of acetylcholinesterase recovery is proposed. In conclusion, cholinesterase inhibitors are the only pharmacological agents proved to be effective for the treatment of Alzheimer's disease in large, long term, double-blind, placebo-controlled trials. While the efficacy of different cholinesterase inhibitors is similar, their tolerability profiles differ. For example, the incidence of nausea (in excess of that seen with placebo) at cognitively effective dosages ranges from 1% with eptastigmine 60 mg/day to 53% with physostigmine 30 mg/day. Differences in tolerability profile may be due to the extent of peripheral acetylcholinesterase inhibition needed to reach clinical efficacy. Other contributing pharmacodynamic factors are the rate of onset of and fluctuations in acetylcholinesterase inhibition at steady state.

Synthesis of new cardioselective M2 muscarinic receptor antagonists.

A series of 5H-dibenz[b,f]azepine derivatives was prepared and evaluated for binding affinities to muscarinic receptors in vitro. Among them, compound 8 showed a high affinity for human recombinant M2 receptors (Ki=2.6 nm), a low affinity for M4 receptors (39-fold less than for M2 receptors) and a very low affinity for M1 and M3 receptors (119- and 112-fold less than for M2 receptors, respectively). The high M2 selectivity of 8 may be attributed to the olefinic bond of the azepine ring. Functional experiments showed 8 to be a competitive antagonist with high affinity to the cardiac (pA2=7.1) and low affinity to the intestinal muscarinic receptors (IC50=0.54 microM). In vivo experiments confirmed the in vitro M, selectivity of 8. Acetylcholine-induced bradycardia was dose-dependently antagonized in rats after both intravenous and intraduodenal administration of 8. In rats, cholinergic functions mediated by M1 or M3 receptors (salivary secretion, pupil diameter, gastric emptying, intestinal transit time) were not affected by the oral administration of 8 even at doses as high as 30 times the antibradycardic effective dose. Furthermore, 8 had no analgesic activity in mice, indicating poor central nervous system penetration. In dogs, nocturnal bradycardia was dose-dependently inhibited by the oral route with a duration of action of about 24 h. Compound 8 appears to be a promising cardioselective antimuscarinic agent for the treatment of dysfunctions of the cardiac conduction system such as sinus or nodal bradycardia ("sick-sinus syndrome") and atrioventricular block.

Hemodynamic effects of MF 10058, a new cardioselective muscarinic M(2) receptor antagonist, in conscious dogs.

The 5-¿4-[4-(diethylamino)butyl]-1-piperidinyl¿acetyl-5H-dibenz[b, f]-azepine (MF 10058) is a new potent and selective muscarinic M(2) receptor antagonist. The hemodynamic effects of MF 10058 were investigated in conscious freely moving dogs. Placebo and three doses of MF 10058 (2, 4 and 8 mg/kg) were orally administered according to a randomised four-way crossover design. Heart rate, cardiac conduction times, systolic and diastolic blood pressure were telemetrically recorded for 12-24 h after dosing. After placebo administration, a consistent reduction over time in heart rate was observed during the night-time period (-15%, P=0.019). MF 10058 administration antagonised the nocturnal bradycardia and shortened QT interval. The effect of the drug reached statistically significance, compared to placebo, with the highest dose of 8 mg/kg (+19% on heart rate, P=0.013; -4% on QT interval, P=0.049). The effect on heart rate lasted for the entire 24-h observation period (+16%, P=0.030). Nocturnal systolic and diastolic blood pressure were not significantly affected by MF 10058. No other signs of peripheral or central cholinergic block were observed at any dose. The results of this study demonstrated that oral administration of MF 10058 produces long-lasting hemodynamic effects in the conscious dog. The drug has a therapeutic potential for the treatment of bradycardic disorders.

A 6-month, double-blind, placebo-controlled trial of eptastigmine in Alzheimer's disease.

OBJECTIVES: To evaluate the efficacy and safety of eptastigmine as a treatment for patients with mild-to-moderate Alzheimer's disease (AD). PATIENTS AND METHODS: The study was designed as a randomized, double-blind, placebo-controlled, parallel-group study. It was performed in 26 Italian and American geriatric and neurological centers. The study group comprised 349 outpatients with a diagnosis of probable AD according to the criteria of the National Institute of Neurological and Communicative Disorders and Stroke and the AD and Related Disorders Association. Patients were assigned to one of the three study groups: placebo (n = 119), eptastigmine 10 mg t.i.d. (n = 115) or eptastigmine 12 mg t.i.d. (n = 115) for 25 weeks. The AD Assessment Cognitive Subscale (ADAS-Cog) and the Clinical Dementia Rating Scale-Sum of the Boxes (CDR-SB) were the primary outcome measures for efficacy. RESULTS: The two doses of eptastigmine produced similar results and are presented together. Percentages of patients completing double-blind treatment were 82 and 87% in the placebo and eptastigmine groups, respectively. At the end of treatment, the intent to-treat analysis on 342 patients showed a statistically significant effect of eptastigmine compared to placebo on both ADAS-Cog (p = 0.047) and CDR-SB (p = 0.010). Patients on eptastigmine performed significantly better than placebo-treated patients also on the Mini-Mental State Examination (p < 0.001). The drug was well tolerated with 5% of patients withdrawing due to adverse events versus 3% on placebo. Adverse events were recorded in 46% of the patients on placebo compared to 52% of the patients taking eptastigmine. Cholinergic side effects (nausea, vomiting, diarrhea and abdominal pain) were reported with similar frequency in the eptastigmine and placebo-treated patients. CONCLUSION: Eptastigmine doses up to 12 mg t.i.d. for 25 weeks are well tolerated. The drug positively affects cognitive performance and global function of patients with mild-to-moderate AD.

Pharmacodynamics of a long acting depot preparation of avorelin in patients with prostate cancer. Avorelin Study Group.

PURPOSE: We evaluate the pharmacodynamics, pharmacokinetics and tolerability of a sustained release depot formulation of avorelin, a new potent super agonist of luteinizing hormone-releasing hormone receptors, in patients with prostate cancer. MATERIALS AND METHODS: A total of 60 patients were randomized to receive a 10 mg. (31) or 15 mg. (29) avorelin subcutaneous depot. Serum testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH) and plasma avorelin were measured regularly until depot exhaustion. RESULTS: Of the 10 mg. group patients 3 withdrew from the study after 31 to 35 weeks due to disease progression. Of the 15 mg. group patients 1 did not complete the study for logistical reasons. After the expected flare in serum testosterone, LH and FSH during week 1, medical castration (testosterone concentration less than 1.735 nmol./l.) was achieved within 4 weeks of depot injection. Median duration of testosterone suppression was 40 weeks in the 10 mg. (95% confidence interval 35 to 42) and 39 in the 15 mg. (37 to 43) group. The reduction in serum LH was similar to that of testosterone, while that of FSH was less pronounced. Plasma avorelin was proportional to the dose and correlated with serum testosterone. Normalization of serum prostate specific (4 ng./ml. or less) at 6 months was achieved in 80 and 88% of the 10 and 15 mg. groups, respectively. During the (7 to 20-month) observation period 94 and 86% of the 10 and 15 mg. groups, respectively, complained of adverse events mainly related to androgen suppression (hot flushes, decreased libido and impotence) or the nature of the disease (skeletal pain). In each group 3 patients had serious adverse events requiring hospitalization for reasons unrelated to avorelin treatment. The depot was well tolerated locally. CONCLUSIONS: Subcutaneous depot formulations of avorelin were well tolerated and had protracted inhibitory effects on pituitary gonadotropin secretion in patients with prostate cancer. Testosterone suppression was maintained for more than 6 months in all patients. Avorelin depots could be the first luteinizing hormone-releasing hormone agonist formulation to be administered at 6-month intervals.

Suicide in two patients with a diagnosis of probable Alzheimer disease.

Two patients meeting the criteria for probable Alzheimer disease (AD) who were participating in a phase 3 clinical program with eptastigmine, a cholinesterase inhibitor, committed suicide. The first patient committed suicide by a self-inflicted gunshot wound to the head. The second patient committed suicide by jumping from a 19th story window. These two patients shared several clinical features with those found in the literature: being at the early stages of the disease, having a high level education, with preserved insight, having access to firearms, and being aware of not responding to pharmacological treatment.

Efficacy and safety of eptastigmine for the treatment of patients with Alzheimer's disease.

OBJECTIVE: To evaluate the efficacy and safety of eptastigmine in patients with moderate to moderately severe AD. BACKGROUND: Eptastigmine is a centrally acting cholinesterase inhibitor. METHODS: The study was carried out according a multicenter, randomized, double-blinded, placebo-controlled, parallel-group design. Patients received a 24-week treatment with placebo or eptastigmine 15 mg or 20 mg three times daily after a 4-week, stepwise dose escalation. The effects of treatment on cognition, global function, and activities of daily living were evaluated with the Alzheimer's Disease Assessment Cognitive Subscale (ADAS-Cog), the Clinician's Interview-Based Impression of Change Plus (CIBIC-Plus), and the Instrumental Activities of Daily Living scale (IADL), respectively. RESULTS: Thirty-six centers recruited 491 patients: 164 on placebo, 166 on eptastigmine 15 mg three times daily, and 161 on eptastigmine 20 mg three times daily. Percentages of patients completing double-blinded treatment were 87% in the placebo group and 86% in both the eptastigmine-treated groups. At the end of treatment, the intent-to-treat analysis on 463 patients showed a dose-dependent effect of eptastigmine on all efficacy variables, with a statistically significant effect of the 20 mg three times daily dose compared with placebo on the ADAS-Cog, CIBIC-Plus, and IADL. Patients on eptastigmine 15 mg three times daily performed significantly better than placebo-treated patients only on the ADAS-Cog. Eleven patients on placebo (7%), 13 patients on eptastigmine 15 mg three times daily (8%), and 12 patients on eptastigmine 20 mg three times daily (8%) discontinued study treatment because of adverse events. Adverse events were recorded in 49% of patients on placebo compared with 54% on eptastigmine 15 mg three times daily and 48% on eptastigmine 20 mg three times daily. Cholinergic side effects (nausea, vomiting, diarrhea, and abdominal pain) were reported with similar frequency in the eptastigmine- and placebo-treated patients. There was a dose-dependent transient and mild neutropenic effect associated with eptastigmine treatment, and one patient on 20 mg three times daily had an asymptomatic pancytopenia. CONCLUSIONS: Eptastigmine produces significant cognitive, clinical, and functional benefits in patients with probable AD. Although the cholinergic tolerability of eptastigmine was found to be favorable, its potential adverse hematologic effects limit its clinical utility.

Two-year treatment of Alzheimer's disease with eptastigmine. The Eptastigmine Study Group.

The effectiveness of long-term treatment of Alzheimer's disease with cholinesterase inhibitors is a matter of controversy. We evaluated the effects of prolonged treatment with eptastigmine in 176 patients with mild to moderate Alzheimer's disease participating in the open-label extension phase of a 25-week double-blind, placebo-controlled trial of eptastigmine. The effects of eptastigmine on cognition and daily functioning were evaluated with the cognitive portion of the Alzheimer's Disease Assessment Scale (ADAS-Cog) and the Instrumental Activities of Daily Living (IADL) scale, respectively. Safety was monitored by physical examination, laboratory tests, vital functions and electrocardiogram measurements and by the assessment of adverse events. One hundred and fifty-three patients (87%) completed 1 year of treatment, 77 patients (44%) 18 months and 33 patients (19%) 2 years of treatment. Patients treated for 2 years showed an improvement of mean ADAS-Cog scores compared to baseline for 31 weeks and mean IADL scores remained close to baseline for 25 weeks. Cognitive and functional scores then worsened as expected in this progressive disease. After 2 years, patients deteriorated compared to baseline by 13.4 points on the ADAS-Cog and 6.1 points on IADL. Historical untreated controls with identical disease severity are expected to have an annual worsening of approximately 10.9 points on ADAS-Cog and 4.9 points on IADL. Thus patients treated with eptastigmine for 2 years had a benefit of 8.5 points on ADAS-Cog and 3.8 points on IADL. These benefits translate to about 9 months difference between eptastigmine-treated patients and untreated historical patients. The drug was generally well tolerated with 14 patients (7.9%) withdrawing due to adverse events. Adverse events, not necessarily drug-related, were recorded in 66 patients (37.5%) and were transient and generally mild in severity. This study indicates that prolonged treatment with eptastigmine is safe and produced a clinically long-term benefit in patients with Alzheimer's disease.

Maximum tolerated dose and pharmacodynamics of eptastigmine in elderly healthy volunteers.

Eptastigmine is a new acetylcholinesterase (AChE) inhibitor currently under development for the symptomatic treatment of Alzheimer disease. This study was conducted to establish the maximum tolerated dose and the pharmacodynamics of eptastigmine in nine healthy elderly volunteers. Subjects received single oral doses of 8 mg, 20 mg, 32 mg, and 40 mg eptastigmine and placebo according to a double-blind, randomized, rising-dose, five-way crossover design. Adverse events, blood pressure, heart rate, body temperature, forced expiratory volume, salivary flow, and pupilar activity were closely monitored during treatment. Pharmacodynamic activity of eptastigmine was evaluated with an assay of AChE activity in red blood cells. Eptastigmine doses of 8 mg, 20 mg, and 32 mg were well tolerated. Two of four subjects receiving the 40-mg dose developed profound AChE inhibition (58-59%) and reported severe adverse events (nausea, vomiting, syncope, and bradycardia), precluding further administration in the remaining subjects. Eptastigmine administration produced a weak effect on supine heart rate, body temperature, and pupil diameter. There were no effects on blood pressure, forced expiratory volume, salivary flow, and near point of focus. Acetylcholinesterase activity was inhibited in a dose-related fashion according to a sigmoidal (logistic) function. The mean (+/- SEM) maximum inhibition of AChE activity (Imax) was 14.5+/-3.3%, 20.4+/-2.3%, 28.7+/-2.9%, 45.2+/-1.3% and 53.6+/-2.9% after placebo, 8 mg, 20 mg, 32 mg, and 40 mg of eptastigmine, respectively. The theoretical maximum response (Emax) was 72.9%, and the dose that produced half of the maximum response (ED50) was 29.5 mg. At 24 hours, residual AChE inhibition ranged from 9% to 15%, with a half-life of recovery of the enzyme of approximately 10 hours. The maximum tolerated dose of eptastigmine after single-dose oral administration in healthy elderly subjects is 32 mg. Single oral doses of eptastigmine produce sustained, dose-related inhibition of AChE activity. Adverse events are related to the degree of AChE inhibition.

Effect of food on the absorption of eptastigmine.

OBJECTIVE: The aim of the study was to evaluate the effects of food on the rate and extent of eptastigmine absorption in healthy volunteers. METHODS: The study was carried out according to a double-blind, randomized, placebo-controlled, three-way cross-over design. On three separate occasions, six young subjects received 30 mg eptastigmine after a 12-h overnight fast (reference treatment), 30 mg eptastigmine 15 min after a standard breakfast (test treatment) and placebo 15 min after a standard breakfast (control treatment). Acetylcholinesterase activity in red blood cells was assayed 24 h after drug administration as a biological marker of eptastigmine plasma concentrations. RESULTS: Mean maximum acetylcholinesterase inhibition (Imax) was 39.9% after eptastigmine without food and 33.1% after eptastigmine with food. Maximum inhibitions occurred at 4.75 h and 4.88 h after eptastigmine without and with food, respectively. Areas under the curve of acetylcholinesterase per cent inhibition from 0 to 8 h after drug administration (AUC0-8) were 198% h after eptastigmine without food and 124% h after eptastigmine with food. Ninety per cent confidence intervals of test/reference ratios for AUC0-8 and Imax exceeded the 0.80 to 1.20 limits, thus indicating that the two eptastigmine treatments cannot be considered bioequivalent. Mild and transient adverse events were recorded in three subjects receiving eptastigmine without food, one subject receiving eptastigmine with food and one subject receiving placebo. CONCLUSIONS: The ingestion of food significantly reduces the bioavailability of eptastigmine estimated by the assay of red blood cell acetylcholinesterase activity.