Development of a Unique Rapid Test to Detect Anti-bodies Directed Against an Extended RBD of SARS-CoV-2 Spike Protein

Serological testing for antibodies directed against SARS-CoV-2 in patients may serve as a diagnostic tool to verify a previous infection and as surrogate for an elicited humoral immune response, ideally conferring immunity after infection or vaccination. Here, we present the recombinant expression of an extended receptor binding domain (RBD) of the SARS-CoV-2 Spike protein used as capture antigen in a unique rapid immunoassay to detect the presence of RBD binding antibodies with high sensitivity and specificity. As currently available vaccines focus on the Spike RBD as target, the developed test can also be used to monitor a successful immune response after vaccination with an RBD based vaccine.

Association Between Motor and Cognitive Performances in Elderly With Atrial Fibrillation: Strat-AF Study

Background/Objective: Growing evidence suggests a close relationship between motor and cognitive abilities, but possible common underlying mechanisms are not well-established. Atrial fibrillation (AF) is associated with reduced physical performance and increased risk of cognitive decline. The study aimed to assess in a cohort of elderly AF patients: (1) the association between motor and cognitive performances, and (2) the influence and potential mediating role of cerebral lesions burden.

Design: Strat-AF is a prospective, observational study investigating biological markers for cerebral bleeding risk stratification in AF patients on oral anticoagulants. Baseline cross-sectional data are presented here.

Setting: Thrombosis outpatient clinic (Careggi University Hospital).

Participants: One-hundred and seventy patients (mean age 77.7 ± 6.8; females 35%).

Measurements: Baseline protocol included: neuropsychological battery, motor assessment [Short Physical Performance Battery (SPPB), and walking speed], and brain magnetic resonance imaging (MRI) used for the visual assessment of white matter hyperintensities, lacunar and non-lacunar infarcts, cerebral microbleeds, and global cortical and medial temporal atrophies.

Results: Mean Montreal Cognitive Assessment (MoCA) total score was 21.9 ± 3.9, SPPB total score 9.5 ± 2.2, and walking speed 0.9 ± 0.2. In univariate analyses, both SPPB and walking speed were significantly associated with MoCA (r = 0.359, r = 0.372, respectively), visual search (r = 0.361, r = 0.322), Stroop (r = −0.272, r = −0.263), short story (r = 0.263, r = 0.310), and semantic fluency (r = 0.311, r = 0.360). In multivariate models adjusted for demographics, heart failure, physical activity, and either stroke history (Model 1) or neuroimaging markers (Model 2), both SPPB and walking speed were confirmed significantly associated with MoCA (Model 1: β = 0.256, β = 0.236; Model 2: β = 0.276, β = 0.272, respectively), visual search (Model 1: β = 0.350, β = 0.313; Model 2: β = 0.344, β = 0.307), semantic fluency (Model 1: β = 0.223, β = 0.261), and short story (Model 2: β = 0.245, β = 0.273).

Conclusions: In our cohort of elderly AF patients, a direct association between motor and cognitive functions consistently recurred using different evaluation of the performances, without an evident mediating role of cerebral lesions burden.

4-(Difluoromethyl)-5-(4-((3R,5S)-3,5-dimethylmorpholino)-6-((R)-3-methylmorpholino)-1,3,5-triazin-2-yl)pyridin-2-amine (PQR626), a Potent, Orally Available, and Brain-Penetrant mTOR Inhibitor for the Treatment of Neurological Disorders

The mechanistic target of rapamycin (mTOR) pathway is hyperactivated in cancer and neurological disorders. Rapalogs and mTOR kinase inhibitors (TORKi) have recently been applied to alleviate epileptic seizures in tuberous sclerosis complex (TSC). Herein, we describe a pharmacophore exploration to identify a highly potent, selective, brain penetrant TORKi. An extensive investigation of the morpholine ring engaging the mTOR solvent exposed region led to the discovery of PQR626 (8). 8 displayed excellent brain penetration and was well-tolerated in mice. In mice with a conditionally inactivated Tsc1 gene in glia, 8 significantly reduced the loss of Tsc1-induced mortality at 50 mg/kg p.o. twice a day. 8 overcomes the metabolic liabilities of PQR620 (52), the first-in-class brain penetrant TORKi showing efficacy in a TSC mouse model. The improved stability in human hepatocytes, excellent brain penetration, and efficacy in Tsc1^GFAPCKO mice qualify 8 as a potential therapeutic candidate for the treatment of neurological disorders.

Abstract 665: Discovery and preclinical characterization of PQR626: A potent, orally available, and brain-penetrant mTOR inhibitor for the treatment of tuberous sclerosis complex

Mechanistic target of rapamycin (mTOR), a key player in cell proliferation, growth and survival, is overactivated in tumors and neurological disorders.[1] Rapalogs have recently been explored to alleviate epileptic seizures in Tuberous Sclerosis Complex (TSC).[2] Herein, we combined pharmacophore features of PQR620[3], the first-in-class brain penetrant ATP-competitive mTOR kinase inhibitor showing efficacy in a TSC mouse model, and PQR617[4], a potent, highly selective mTOR inhibitor. An extensive chemical exploration of the morpholine ring led to the discovery of PQR626, a highly potent, selective, brain penetrant inhibitor of mTORC1/2 kinase. In male Sprague Dawley rats and female C57BL/6J mice, PQR626 displayed an excellent brain penetration compared to everolimus, which possessed a limited ability to cross the blood-brain-barrier (brain/plasma levels ~ 1.4:1 vs 1:92). An additional pharmacokinetic comparative study with everolimus and AZD2014 confirmed the superiority of PQR626 [brain/plasma levels: ~ 1:25 (AZD2014), ~ 1:61 (everolimus), ~ 1.8:1 (PQR626)]. PQR626 showed very good tolerability in mice (MTD 100-150 mg/kg). Efficacy studies, using mice with conditional inactivation of the Tsc1 gene primarily in glia (Tsc1GFAPCKO mice), were performed in a dose-range finding study. PQR626 (50 mg/kg, BID - twice a day) showed a significant effect on survival and significantly prevented/decreased mortality as compared to the vehicle. On the basis of its favorable pharmacological parameters, excellent brain penetration, safety profile and efficacy in Tsc1GFAPCKO mice, PQR626 qualifies as a novel mTOR inhibitor with potential application in the treatment of epilepsy and neurological disorders. [1] Wymann M. P. and Schneiter R. Nat. Rev. Mol. Cell Biol. 2008, 9, 162-176. [2] Krueger D. A. et. al. Neurology 2016, 87, 2408-2415. [3] Rageot D. et. al. J Med Chem. 2018, 61 (22), 10084-10105. [4] Borsari C. et. al. J Med Chem. 2019, 62 (18), 8609-8630.

Citation Format: Chiara Borsari, Erhan Keles, Denise Rageot, Anna Melone, Thomas Bohnacker, Lucinda Kate Batchelor, Martina De Pascale, Paul Hebeisen, Petra Hillmann, Doriano Fabbro, Matthias Wymann. Discovery and preclinical characterization of PQR626: A potent, orally available, and brain-penetrant mTOR inhibitor for the treatment of tuberous sclerosis complex [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 665.

Association of nimodipine and choline alphoscerate in the treatment of cognitive impairment in patients with cerebral small vessel disease: study protocol for a randomized placebo-controlled trial-the CONIVaD trial

BACKGROUND

Vascular cognitive impairment (VCI) is an extremely disabling condition that includes post-stroke dementia and VCI caused by cerebral small vessel disease (SVD). Currently, there is no approved treatment for this condition. Drugs active on the cholinergic pathway have been tested in VCI patients showing positive but limited efficacy. The calcium-antagonist nimodipine also showed some moderate positive effects in VCI patients.

AIMS

CONIVaD (choline alphoscerate and nimodipine in vascular dementia) is a pilot, single-center, double-blinded, randomized trial aimed to assess whether the association of choline alphoscerate and nimodipine is more effective than nimodipine alone in reducing cognitive decline in patients with SVD and mild-to-moderate cognitive impairment.

METHODS

All patients are evaluated at baseline and after 12 months with: (1) clinical, daily functions, quality of life, and mood assessment and (2) extensive neuropsychological evaluation. After the baseline evaluation, patients are randomly assigned to one of the two arms of treatment: (1) nimodipine 90 mg/die t.i.d plus placebo b.i.d and (2) nimodipine 90 mg t.i.d plus choline alphoscerate 1200 mg/die b.i.d. for a total of 12 months. The primary endpoint is cognitive decline, expressed as the loss of at least two points on the Montreal Cognitive Assessment at 12 months. Secondary endpoints include safety and tolerability, functional, quality of life, and neuropsychological measures.

DISCUSSION

CONIVaD study is the first randomized controlled trial to examine the cognitive efficacy of combined choline alphoscerate-nimodipine treatment in VCI patients. Results of this pilot study will serve as a methodological basis for other clinical controlled, multicentric, double-blinded, and randomized trials.

TRIAL REGISTRATION

Clinical Trial NCT03228498. Registered 25 July 2017.

Preclinical Development of PQR514, a Highly Potent PI3K Inhibitor Bearing a Difluoromethyl-Pyrimidine Moiety

The phosphoinositide 3-kinase (PI3K)/mechanistic target of rapamycin (mTOR) pathway is a critical regulator of cell growth and is frequently hyperactivated in cancer. Therefore, PI3K inhibitors represent a valuable asset in cancer therapy. Herein we have developed a novel anticancer agent, the potent pan-PI3K inhibitor PQR514 (4), which is a follow-up compound for the phase-II clinical compound PQR309 (1). Compound 4 has an improved potency both in vitro and in cellular assays with respect to its predecessor compounds. It shows superiority in the suppression of cancer cell proliferation and demonstrates significant antitumor activity in an OVCAR-3 xenograft model at concentrations approximately eight times lower than PQR309 (1). The favorable pharmacokinetic profile and a minimal brain penetration promote PQR514 (4) as an optimized candidate for the treatment of systemic tumors.

Role of Biological Markers for Cerebral Bleeding Risk STRATification in Patients with Atrial Fibrillation on Oral Anticoagulants for Primary or Secondary Prevention of Ischemic Stroke (Strat-AF Study): Study Design and Methodology

Background and Objectives: In anticoagulated atrial fibrillation (AF) patients, the validity of models recommended for the stratification of the risk ratio between benefits and hemorrhage risk is limited. Cerebral small vessel disease (SVD) represents the pathologic substrate for primary intracerebral hemorrhage and ischemic stroke. We hypothesize that biological markers-both circulating and imaging-based-and their possible interaction, might improve the prediction of bleeding risk in AF patients under treatment with any type of oral anticoagulant. Materials and Methods: The Strat-AF study is an observational, prospective, single-center hospital-based study enrolling patients with AF, aged 65 years or older, and with no contraindications to magnetic resonance imaging (MRI), referring to Center of Thrombosis outpatient clinic of our University Hospital for the management of oral anticoagulation therapy. Recruited patients are evaluated by means of a comprehensive protocol, with clinical, cerebral MRI, and circulating biomarkers assessment at baseline and after 18 months. The main outcome is SVD progression-particularly microbleeds-as a selective surrogate marker of hemorrhagic complication. Stroke occurrence (ischemic or hemorrhagic) and the progression of functional, cognitive, and motor status will be evaluated as secondary outcomes. Circulating biomarkers may further improve predictive potentials. Results: Starting from September 2017, 194 patients (mean age 78.1 ± 6.7, range 65-97; 61% males) were enrolled. The type of AF was paroxysmal in 93 patients (48%), and persistent or permanent in the remaining patients. Concerning the type of oral anticoagulant, 57 patients (29%) were on vitamin K antagonists, and 137 (71%) were on direct oral anticoagulants. Follow-up clinical evaluation and brain MRI are ongoing. Conclusions: The Strat-AF study may be an essential step towards the exploration of the role of a combined clinical biomarker or multiple biomarker models in predicting stroke risk in AF, and might sustain the incorporation of such new markers in the existing stroke prediction schemes by the demonstration of a greater incremental value in predicting stroke risk and improvement in clinical outcomes in a cost-effective fashion.

A Conformational Restriction Strategy for the Identification of a Highly Selective Pyrimido-pyrrolo-oxazine mTOR Inhibitor

The mechanistic target of rapamycin (mTOR) plays a pivotal role in growth and tumor progression and is an attractive target for cancer treatment. ATP-competitive mTOR kinase inhibitors (TORKi) have the potential to overcome limitations of rapamycin derivatives in a wide range of malignancies. Herein, we exploit a conformational restriction approach to explore a novel chemical space for the generation of TORKi. Structure-activity relationship (SAR) studies led to the identification of compound 12b with a ∼450-fold selectivity for mTOR over class I PI3K isoforms. Pharmacokinetic studies in male Sprague Dawley rats highlighted a good exposure after oral dosing and a minimum brain penetration. CYP450 reactive phenotyping pointed out the high metabolic stability of 12b. These results identify the tricyclic pyrimido-pyrrolo-oxazine moiety as a novel scaffold for the development of highly selective mTOR inhibitors for cancer treatment.

(S)-4-(Difluoromethyl)-5-(4-(3-methylmorpholino)-6-morpholino-1,3,5-triazin-2-yl)pyridin-2-amine (PQR530), a Potent, Orally Bioavailable, and Brain-Penetrable Dual Inhibitor of Class I PI3K and mTOR Kinase

The phosphoinositide 3-kinase (PI3K)/mechanistic target of rapamycin (mTOR) pathway is frequently overactivated in cancer, and drives cell growth, proliferation, survival, and metastasis. Here, we report a structure-activity relationship study, which led to the discovery of a drug-like adenosine 5'-triphosphate-site PI3K/mTOR kinase inhibitor: (S)-4-(difluoromethyl)-5-(4-(3-methylmorpholino)-6-morpholino-1,3,5-triazin-2-yl)pyridin-2-amine (PQR530, compound 6), which qualifies as a clinical candidate due to its potency and specificity for PI3K and mTOR kinases, and its pharmacokinetic properties, including brain penetration. Compound 6 showed excellent selectivity over a wide panel of kinases and an excellent selectivity against unrelated receptor enzymes and ion channels. Moreover, compound 6 prevented cell growth in a cancer cell line panel. The preclinical in vivo characterization of compound 6 in an OVCAR-3 xenograft model demonstrated good oral bioavailability, excellent brain penetration, and efficacy. Initial toxicity studies in rats and dogs qualify 6 for further development as a therapeutic agent in oncology.

Discovery and Preclinical Characterization of 5-[4,6-Bis({3-oxa-8-azabicyclo[3.2.1]octan-8-yl})-1,3,5-triazin-2-yl]-4-(difluoromethyl)pyridin-2-amine (PQR620), a Highly Potent and Selective mTORC1/2 Inhibitor for Cancer and Neurological Disorders

Mechanistic target of rapamycin (mTOR) promotes cell proliferation, growth, and survival and is overactivated in many tumors and central nervous system disorders. PQR620 (3) is a novel, potent, selective, and brain penetrable inhibitor of mTORC1/2 kinase. PQR620 (3) showed excellent selectivity for mTOR over PI3K and protein kinases and efficiently prevented cancer cell growth in a 66 cancer cell line panel. In C57BL/6J and Sprague-Dawley mice, maximum concentration ( C_max) in plasma and brain was reached after 30 min, with a half-life ( t_1/2) > 5 h. In an ovarian carcinoma mouse xenograft model (OVCAR-3), daily dosing of PQR620 (3) inhibited tumor growth significantly. Moreover, PQR620 (3) attenuated epileptic seizures in a tuberous sclerosis complex (TSC) mouse model. In conclusion, PQR620 (3) inhibits mTOR kinase potently and selectively, shows antitumor effects in vitro and in vivo, and promises advantages in CNS indications due to its brain/plasma distribution ratio.

Radiological study to evaluate the spreading of two volumes (10 vs. 20ml) of radiological contrast in the block of cutaneous branches of intercostal nerves in medial axillary line (BRILMA) in a porcine experimental model

OBJECTIVE

Interfascial blocks of the thoracic wall are being developed as an alternative to central blocks in breast surgery. However, there are few studies that have evaluated the anatomical extension of the local anaesthetic. The objective of this study was to analyse, using fluoroscopy, the spreading of two volumes (10 vs. 20ml) of radiological contrast in the serratus-intercostal plane block in an experimental pig model.

MATERIAL AND METHODS

Ten Large-White breed pigs were selected to have a bilateral ultrasound serratus-intercostal plane block performed, with the administering of 10ml and 20ml of iopamidol in the right and left hemithorax, respectively. The spreading of contrast was analysed by fluoroscopy. The Spearman test correlation was used to evaluate the relationship between the administered volume and radiological spreading. A value of P<.05 was considered significant.

RESULTS

Twenty anaesthetic blocks were performed, being able to analyse 18 of them. The administration of 10ml of contrast was associated with a mean spreading of 2.28±0.31 (95% CI; 2.01-2.54) intercostal spaces, while the administration of 20ml showed a spreading of 3±0.25 (95% CI; 2.81-3.18) intercostal spaces. There was a significant correlation between the injected volume and the spreading of the contrast (Spearman correlation coefficient of 0.81; P=.0001).

CONCLUSION

The results showed a spreading of volume subject to the serratus-intercostal plane block, although not maintaining a 1:1 ratio. Doubling the volume increased the blocked segments by 31%. These findings, if corroborated in the clinical practice, would allow a more precise adjustment in the anaesthetic volume administered.

The novel, catalytic mTORC1/2 inhibitor PQR620 and the PI3K/mTORC1/2 inhibitor PQR530 effectively cross the blood-brain barrier and increase seizure threshold in a mouse model of chronic epilepsy

The mTOR signaling pathway has emerged as a possible therapeutic target for epilepsy. Clinical trials have shown that mTOR inhibitors such as everolimus reduce seizures in tuberous sclerosis complex patients with intractable epilepsy. Furthermore, accumulating preclinical data suggest that mTOR inhibitors may have anti-seizure or anti-epileptogenic actions in other types of epilepsy. However, the chronic use of rapalogs such as everolimus is limited by poor tolerability, particularly by immunosuppression, poor brain penetration and induction of feedback loops which might contribute to their limited therapeutic efficacy. Here we describe two novel, brain-permeable and well tolerated small molecule 1,3,5-triazine derivatives, the catalytic mTORC1/C2 inhibitor PQR620 and the dual pan-PI3K/mTOR inhibitor PQR530. These derivatives were compared with the mTORC1 inhibitors rapamycin and everolimus as well as the anti-seizure drugs phenobarbital and levetiracetam. The anti-seizure potential of these compounds was determined by evaluating the electroconvulsive seizure threshold in normal and epileptic mice. Rapamycin and everolimus only poorly penetrated into the brain (brain:plasma ratio 0.0057 for rapamycin and 0.016 for everolimus). In contrast, the novel compounds rapidly entered the brain, reaching brain:plasma ratios of ∼1.6. Furthermore, they significantly decreased phosphorylation of S6 ribosomal protein in the hippocampus of normal and epileptic mice, demonstrating effective mTOR inhibition. PQR620 and PQR530 significantly increased seizure threshold at tolerable doses. The effect of PQR620 was more marked in epileptic vs. nonepileptic mice, matching the efficacy of levetiracetam. Overall, the novel compounds described here have the potential to overcome the disadvantages of rapalogs for treatment of epilepsy and mTORopathies directly connected to mutations in the mTOR signaling cascade.

5-(4,6-Dimorpholino-1,3,5-triazin-2-yl)-4-(trifluoromethyl)pyridin-2-amine (PQR309), a Potent, Brain-Penetrant, Orally Bioavailable, Pan-Class I PI3K/mTOR Inhibitor as Clinical Candidate in Oncology

Phosphoinositide 3-kinase (PI3K) is deregulated in a wide variety of human tumors and triggers activation of protein kinase B (PKB/Akt) and mammalian target of rapamycin (mTOR). Here we describe the preclinical characterization of compound 1 (PQR309, bimiralisib), a potent 4,6-dimorpholino-1,3,5-triazine-based pan-class I PI3K inhibitor, which targets mTOR kinase in a balanced fashion at higher concentrations. No off-target interactions were detected for 1 in a wide panel of protein kinase, enzyme, and receptor ligand assays. Moreover, 1 did not bind tubulin, which was observed for the structurally related 4 (BKM120, buparlisib). Compound 1 is orally available, crosses the blood-brain barrier, and displayed favorable pharmacokinetic parameters in mice, rats, and dogs. Compound 1 demonstrated efficiency in inhibiting proliferation in tumor cell lines and a rat xenograft model. This, together with the compound's safety profile, identifies 1 as a clinical candidate with a broad application range in oncology, including treatment of brain tumors or CNS metastasis. Compound 1 is currently in phase II clinical trials for advanced solid tumors and refractory lymphoma.

Abstract 140: Discovery and biological evaluation of PQR530, a highly potent dual pan-PI3K/mTORC1/2 inhibitor

The PI3K/AKT/mTOR signaling pathway plays a fundamental role in cell proliferation, growth and survival and aberrant activation of this signaling pathway has been shown to drive the progression of malignant tumors.[1] Drugs targeting the pathway at multiple points, such as dual PI3K/mTOR inhibitors appear to have the broadest activity profile to address cancer therapeutic strategies and are currently being explored in numerous clinical studies. Recently, we presented PQR309, a novel, brain-penetrant pan-PI3K/mTOR inhibitor, which entered phase II clinical trials in 2016.[2] Here, we report the lead optimization of PQR530, a potent and brain-penetrant follow-up compound as pan-PI3K/mTORC1/2 inhibitor.

The development of a follow-up compound concentrated on the improvement of both, the potency and the selectivity for all targeted kinases, namely the class IA PI3K isoforms as well as mTOR. We present a detailed ligand-based structure-activity relationship study which was obtained by systematic modifications of the hinge region as well as the affinity binding substituents. This study led to the identification of PQR530, a dual pan-PI3K/mTORC1/2 inhibitor showing excellent activities in cellular assays as well as in PI3Kα and mTOR enzymatic binding assays.

In A2058 melanoma cells PQR530 inhibited protein kinase B (PKB, pSer473) and ribosomal protein S6 (pS6, pSer235/236) phosphorylation with IC50 values of 0.07 µM. PQR530 showed excellent selectivity over a wide panel of kinases, as well as excellent selectivity versus unrelated receptor enzymes and ion channels. Moreover, PQR530 displayed potency in a panel of 44 cancer cell lines (NTRC OncolinesTM) to prevent cancer cell growth (mean value for GI50 of 426 nM). Oral application of PQR530 to mice resulted in a dose-proportional PK and demonstrated good oral bioavailability and excellent brain penetration.[3]

An optimized, robust synthetic route allowed rapid access to multi-gram quantities of PQR530 for pre-clinical development in only 4 steps. In conclusion, PQR530 inhibits all PI3K isoforms and the mammalian target of rapamycin (mTOR) complexes C1/2 potently and selectively, and shows anti-tumor effects in vitro and in vivo.

[1] M. P. Wymann, M. Zvelebil, M. Laffargue (2003). Phosphoinositide 3-kinase signalling – which way to target? Trends Pharmacol Sci.; 24, 366-376.

[2] V. Cmiljanovic et. al. “PQR309: Structure-Based Design, Synthesis and Biological Evaluation of a Novel, Selective, Dual Pan-PI3K/mTOR Inhibitor” presented at AACR Annual Meeting 2015, April 18-22, Philadelphia, Pennsylvania, USA.

[3] P. Hillmann et al. “Pharmacological Characterization of the Selective, Orally Bioavailable, Potent Dual PI3K/mTORC1/2 Inhibitor PQR530” abstract submitted for AACR Annual Meeting 2017, April 1-5, Washington, D. C., USA.

Citation Format: Denise Rageot, Florent Beaufils, Anna Melone, Alexander M. Sele, Thomas Bohnacker, Marc Lang, Jürgen Mestan, Petra Hillmann, Paul Hebeisen, Doriano Fabbro, Matthias P. Wymann. Discovery and biological evaluation of PQR530, a highly potent dual pan-PI3K/mTORC1/2 inhibitor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 140. doi:10.1158/1538-7445.AM2017-140

Abstract 153: Tricyclic fused pyrimidinopyrrolo-oxazines reveal conformational preferences of morpholine for PI3K hinge region binding

Class I phosphoinositide 3-kinases (PI3Ks) are lipid kinases, produce PtdIns(3,4,5)P3 and trigger intracellular signaling pathways that are vital to cell growth, proliferation, survival and migration. Constitutive activation of PI3K is frequently observed in many tumor types, which defines PI3K as a valuable drug target in oncology.1

Numerous PI3K inhibitors in clinical development contain a morpholine moiety that mediates hinge region binding in the ATP pocket of PI3K by a hydrogen bond with the active site valine backbone nitrogen (Val851 in PI3Kα)2. We present here novel pyrimidinopyrrolo-oxazines related to the clinically advanced, pyridinylmorpholine and triazinylmorpholine derived pan-PI3K/mTOR inhibitors BKM120 and PQR309. The novel fused tricyclic core of these compounds contains two morpholine moieties of which one is conformationally restricted by the introduction of a methylene bridge that links the pyrimidine core with one of the two morpholine moieties. This modification leads to the generation of two regioisomers, each existing as a set of enantiomers.

We investigated the influence of this conformational restriction on PI3K inhibitory activity and analyzed the distinct selectivity profiles and potencies of the respective stereo- and regio-isomers. The design and preparation of specific compounds in combination with biological assays (phosphorylation of PKB and S6, binding affinity to p110α), structure-activity relationship (SAR) and molecular modelling studies allowed us to understand the binding mode of these compounds and acquire valuable information that potentially lead to the development of derivatives with a distinct selectivity profile (e.g. PI3K versus mTOR).

A selection of compounds demonstrated inhibition of protein kinase B (pSer473) and ribosomal protein S6 (pSer235/236) phosphorylation with IC50 values in the nanomolar range and high inhibitory potency of all PI3K isoforms (Ki(p110α) &gt; 40 nM). Single p.o. administration of our lead compound to SD rats resulted in good oral bioavailability as well as excellent brain penetration. Furthermore, mechanism of action-based increases in glucose levels and insulin levels have been observed.

In conclusion, we present here the development, optimization, preparation and biological evaluation of a novel class of potent, orally available and brain-penetrant pan-PI3K inhibitors that represent an innovative extension to known pyrimidinomorpholine derived PI3K inhibitors. Moreover, our results add to the understanding of how introducing specific structural and conformational modifications can lead to the development of optimized, selective PI3K and mTOR inhibitors.

[1] Thorpe, L. M.; Yuzugullu, H.; Zhao, J. J. Nat. Rev. Cancer 2015, 15, 7-24.

[2] Andrs, M.; Korabecny, J.; Jun, D.; Hodny, Z.; Bartek, J.; Kuca, K. J. Med. Chem. 2015, 58, 41-71.

Citation Format: Alexander M. Sele, Denise Rageot, Florent Beaufils, Anna Melone, Thomas Bohnacker, Eileen Jackson, Jean-Baptiste Langlois, Paul Hebeisen, Doriano Fabbro, Matthias P. Wymann. Tricyclic fused pyrimidinopyrrolo-oxazines reveal conformational preferences of morpholine for PI3K hinge region binding [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 153. doi:10.1158/1538-7445.AM2017-153

Abstract 159: Pharmacological characterization of the selective, orally bioavailable, potent dual PI3K/mTORC1/2 inhibitor PQR530

Introduction: The phosphatidylinositol 3-kinase (PI3K) signaling pathway plays a fundamental role in many cellular processes like growth, survival, proliferation, differentiation and motility. In cancers several mutations have been identified that lead to constitutive activation of PI3K. PQR530 is a novel, ATP site directed inhibitor of all PI3K isoforms and the mammalian target of rapamycin (mTOR) complexes C1/2 that is currently in pre-clinical development. PQR530 potently binds to its targets, inhibits cell proliferation and shows excellent selectivity versus related and unrelated kinases [1].

Results: PQR530 inhibits PI3K signaling in stimulated MCF7 cells as detected by PathScan analysis. Excellent tolerability has been found for PQR530 during GLP toxicological testing in rats and dogs. Increase in insulin and blood glucose, a treatable class effect of PI3K inhibitors, has been observed after PQR530 administration to mice. Investigation of mutagenicity and hERG binding resulted in a clean profile. PQR530 exhibited dose-proportional pharmacokinetics (PK) in male C57BL/6J mice. A maximum concentration (Cmax) in plasma and brain was reached after 30 minutes (7.8 μg/ml and 112.6 μg/ml, respectively) indicating that efficacious concentrations were reached in both tissues. The calculated half-life (t1/2) for plasma and brain was approximately 5 hours. PQR530 potently inhibited PI3K signaling in vivo for several hours after administration of a single oral dose of 50 mg/kg. Tumor growth was significantly decreased in SUDHL-6 lymphoma, RIVA lymphoma and OVCAR-3 ovarian cancer mouse xenografts using daily, oral administration.

Conclusion: PQR530 is a potent, ATP competitive pan-PI3K and mTORC1/2 inhibitor. The physico-chemical properties of PQR530 result in good oral bioavailability and excellent brain penetration. PQR530 is well tolerated and efficiently inhibits tumor growth in xenograft models. Preclinical data allow for further development of the compound.

[1]  Rageot D, et al., Discovery and biological evaluation of PQR530, a highly potent dual pan-PI3K/mTORC1/2 inhibitor, abstract submitted for AACR Annual Meeting 2017, April 1-5, Washington, D. C., USA.

Citation Format: Petra Hillmann, Denise Rageot, Florent Beaufils, Anna Melone, Alexander Sele, Robert A. Ettlin, Jürgen Mestan, Vladimir Cmiljanovic, Marc Lang, Elisabeth Singer, Carolin Walter, Hoa HP Nguyen, Paul Hebeisen, Matthias P. Wymann, Doriano Fabbro. Pharmacological characterization of the selective, orally bioavailable, potent dual PI3K/mTORC1/2 inhibitor PQR530 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 159. doi:10.1158/1538-7445.AM2017-159

Deconvolution of Buparlisib's mechanism of action defines specific PI3K and tubulin inhibitors for therapeutic intervention

BKM120 (Buparlisib) is one of the most advanced phosphoinositide 3-kinase (PI3K) inhibitors for the treatment of cancer, but it interferes as an off-target effect with microtubule polymerization. Here, we developed two chemical derivatives that differ from BKM120 by only one atom. We show that these minute changes separate the dual activity of BKM120 into discrete PI3K and tubulin inhibitors. Analysis of the compounds cellular growth arrest phenotypes and microtubule dynamics suggest that the antiproliferative activity of BKM120 is mainly due to microtubule-dependent cytotoxicity rather than through inhibition of PI3K. Crystal structures of BKM120 and derivatives in complex with tubulin and PI3K provide insights into the selective mode of action of this class of drugs. Our results raise concerns over BKM120's generally accepted mode of action, and provide a unique mechanistic basis for next-generation PI3K inhibitors with improved safety profiles and flexibility for use in combination therapies.

Buparlisib/BKM120 is in phase 3 clinical trials as a phosphoinositide 3-kinase (PI3K) inhibitor. Here, Bohnacker et al. combine chemical biology and structural biology approaches to segregate BKM120's biological actions, and suggest that it causes mitotic arrest predominantly by binding microtubules and disrupting their dynamics.

Utilizzo dell'Axial Loader nello studio della colonna lobosacrale

Lo scopo dello studio è di valutare le modificazioni indotte dall'applicazione di carico assiale durante I'esame RM della colonna lombosacrale. Sono stati sottoposti all'indagine 75 pazienti consecutivi con varie patologie degenerative del rachide lombosacrale, anche già trattati chirurgicamente. I risultati hanno dimostrato varie modificazioni dopo applicazione del carico, in particolare la osservazione più frequente è stata l'aumento della stenosi. In un caso l'esame ottenuto dopo applicazione di carico ha modificato radicalmente il trattamento ponendo indicazione all'intervento chirurgico. Dalle osservazioni preliminari riteniamo che le modificazioni indotte dal carico assiale siano interessanti da valutare con RM; sarà comunque indispensabile uno studio su una popolazione omogenea per diagnosi clinica per verificarne la effettiva utilità.

Abstract 1336: Structure-activity relationship studies, synthesis, and biological evaluation of PQR620, a highly potent and selective mTORC1/2 inhibitor

Mammalian target of rapamycin (mTOR) signaling pathway plays a fundamental role in cell proliferation, differentiation, growth and survival.[1] As a consequence, various tumors and central nervous system (CNS) disorders share aberrant activation of the mTOR pathway. Drugs targeting the mTOR pathway represent therefore a valuable path to address multiple therapeutic areas.[1-2] Here, we report the lead optimization of PQR620, a novel potent and selective brain penetrant inhibitor of mTORC1/2.

The development of selective mTOR inhibitors is particularly challenging due to extensively conserved amino acid residues in the ATP binding pocket within the PI3K and PI3K-related protein kinase family. Here, we present a detailed ligand-based structure activity relationship study allowing selective targeting of mTOR kinase activity without the interference of other PI3K family members. Systematic variation of the hinge region and affinity binding motifs led to the identification of PQR620, a morpholino-triazinyl derivative, as potent and selective mTOR inhibitor. Substitution of the morpholine binding to the hinge region and introduction of a 2-aminopyridine, substituted with a difluoromethyl group, induced a &gt;1000-fold selectivity towards mTOR over PI3Kα in enzymatic binding assays.

In A2058 melanoma cells PQR620 demonstrated inhibition of protein kinase B (pSer473) and ribosomal protein S6 (pSer235/236) phosphorylation with IC50 values of 0.2 μM and 0.1 μM, respectively. The physico-chemical properties of PQR620 result in good oral bioavailability and excellent brain penetration. PQR620 showed excellent selectivity over a wide panel of kinases, as well as excellent selectivity versus unrelated receptor enzymes and ion channels. Moreover, PQR620 demonstrated its potency to prevent cancer cell growth in an NTRC 44 cancer cell line panel, resulting in a 10log(IC50) of 2.86 (nM). Further pharmacological properties and in vivo efficacy of PQR620 are presented in detail in Ref. [3].

The preparation of PQR620 was optimized towards a robust synthetic route involving only 4 steps, allowing for a rapid access to quantities required for pre-clinical testing. In conclusion, PQR620 inhibits mTOR potently and selectively, and shows anti-tumor effects in vitro and in vivo. PQR620 is currently in pre-clinical development.

[1] M. Laplante, D. Sabatini, Cell 2012, 149, 274-293.

[2] Z. Z. Chong, Y. C. Shang, L. Zhang, S. Wang, K. Maiese, Oxid. Med. Cell. Longev. 2010, 3, 374–391.

[3] F. Beaufils, D. Rageot, A. Melone, A. M. Sele, M. Lang, J. Mestan, R. A. Ettlin, P. Hillmann, V. Cmiljanovic, C. Walter, E. Singer, H. P. Nguyen, P. Hebeisen, D. Fabbro, M. P. Wymann, “Pharmacological characterization of the selective, orally bioavailable, potent mTORC1/2 inhibitor PQR620” presented at AACR Annual Meeting 2016, April 16-20, New Orleans, Louisiana, USA.

Citation Format: Florent Beaufils, Denise Rageot, Anna Melone, Marc Lang, Jürgen Mestan, Vladimir Cmiljanovic, Petra Hillmann, Paul Hebeisen, Doriano Fabbro, Matthias P. Wymann. Structure-activity relationship studies, synthesis, and biological evaluation of PQR620, a highly potent and selective mTORC1/2 inhibitor. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1336.

Abstract 393A: Pharmacological characterization of the selective, orally bioavailable, potent mTORC1/2 inhibitor PQR620

Introduction: The mammalian target of rapamycin (mTOR) signaling pathway is an integrating factor in cell physiology that influences many processes like growth, metabolism and proliferation. mTOR signaling is constitutively activated in many cancers. Rapamycin is an allosteric inhibitor of mTOR that targets a subset of mTOR functions via inhibition of the mTORC1 complex. An ATP site-directed mTORC1/2 inhibitor that fully blocks all mTOR functions is desirable as cancer therapeutic. PQR620 is a novel, ATP site directed inhibitor of mTOR that is currently in pre-clinical development. PQR620 potently binds to its target (Kd = 6 nM) and shows excellent selectivity versus related and unrelated kinases [1].

Results: PQR620 inhibits mTOR signaling in stimulated MCF7 cells as detected by PathScan analysis. Excellent tolerability has been observed in mice (MTD = 150 mg/kg). A 14 day GLP toxicological study in rats showed very good tolerability (MTD = 30 mg/kg). Only minor toxicities such as dose-related changes in body weight and blood count were observed. PQR620 was administered to male C57BL/6J mice for a pharmacokinetic (PK) and pharmacodynamics (PD) evaluation. After oral application PQR620 exhibited dose-proportional PK, a maximum concentration (Cmax) in plasma and brain was reached after 30 minutes (4.8 μg/ml and 7.7 μg/ml, respectively). In muscle, Cmax (7.6 μg/ml) was reached after 2 hours. The calculated half-life (t1/2) for plasma and brain was approximately 5 hours. After 8 hours, the total exposure (expressed as AUC0-tz (area under the curve)) was 20.5 μg*h/ml in plasma, while it was approximately 30% higher in both, brain and thigh muscle (30.6 and 32.3 μg*h/ml, respectively). PQR620 potently inhibited mTOR signaling in vivo after administration of a single oral dose of 50 mg/kg. Importantly, no effect on plasma insulin levels was observed. In an OVCAR-3, ovarian carcinoma mouse xenograft, PQR620 effectively attenuated tumor growth using daily, oral dosing.

Conclusion: PQR620 potently inhibits mTORC1/2 in vitro and in vivo. The physico-chemical properties of PQR620 result in good oral bioavailability and excellent brain penetration. PQR620 is well tolerated and efficiently inhibits tumor growth in xenograft models. Preclinical data allow for further development of the compound.

[1] Beaufils F, Rageot D, et al., Structure-Activity Relationship Studies, Synthesis and Biological Evaluation of PQR620, a Highly Potent and Selective mTORC1/2 Inhibitor, AACR annual meeting 2016

Citation Format: Florent Beaufils, Denise Rageot, Anna Melone, Alexander Sele, Marc Lang, Juergen Mestan, Robert A. Ettlin, Petra Hillmann, Vladimir Cmiljanovic, Carolin Walter, Elisabeth Singer, Hoa HP Nguyen, Paul Hebeisen, Doriano Fabbro, Matthias P. Wymann. Pharmacological characterization of the selective, orally bioavailable, potent mTORC1/2 inhibitor PQR620. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 393A.

Abstract 671: BKM120-mediated G2 arrest: Structural and functional segregation of off-target action and PI3K inhibition

Due to its central role in growth, proliferation, survival and migration, phosphoinositide 3-kinase (PI3K) is considered as an important drug target in oncology (1). BKM120 is one of the clinically most advanced PI3K inhibitors (PI3Ki), and is currently listed in more than 80 clinical studies aimed at attenuating tumour progression. As an off-target effect, BKM120 was reported to disrupt microtubules (MT) at concentrations around 1 μM (2).

Here, we elucidate in detail the structural factors defining PI3K- and tubulin-binding of BKM120, and present a pure PI3K inhibitor (PQR309) and a potent MT disruptor (MTD147) differing from BKM120 by only 1 Dalton. Separation of PI3Ki and MT disruption activities of BKM120 allowed profiling of BKM120 against PQR309 and MTD147: cellular growth profiles of PQR309 clustered with other PI3Ki such as GDC0941/GDC0980, while BKM120 matched MTD147. Both yielded a G2/M cell cycle arrest with typical histone3 phosphorylation. Accumulation of G2/M arrested cells was already evident at concentrations yielding 50% growth inhibition. Interestingly, BKM120 concentrations for 50% cell growth inhibition (with evident G2/M arrest) ranged below or within its reported AUC0-24 levels at day 8 in patient plasma (3,4). This result implies that the two activities of BKM120 cannot be separated, thus complicating the understanding of drug action and impacting on the rational of combination therapies at relevant drug doses.

Using X-ray crystallography we found that BKM120 binds to the colchicine pocket on β-tubulin. This study further highlights the importance of the pyrimidine core orientation for tight tubulin binding. Interestingly, activities of regio-isomers of the pyrimidine core are inversed for PI3Ki and tubulin association, and modulate binding by a factor of &gt;30x. Finally, a combination of biochemical, cellular and structural data suggests an inverted orientation of BKM120 in the catalytic cleft of PI3K as previously proposed (6). In summary, the dissection of BKM120 functions allows reassessment of its dominant activity, to increase drug safety, and to flexibly control PI3K and/or MT targeting in combination therapy.

1. M. P. Wymann, R. Schneiter, Nat Rev Mol Cell Biol 9, 162 (2008).; 2. S. M. Brachmann et al., Mol Cancer Ther 11, 1747 (2012). 3. J. C. Bendell et al., J Clin Oncol 30, 282 (2012). 4. C. Saura et al., Clin Cancer Res 20, 1935 (2014). 5. A. E. Prota et al., Science 339, 587 (2013). 6. S. M. Maira et al., Mol Cancer Ther 11, 317 (2012).

Citation Format: Thomas Bohnacker, Florent Beaufils, Andrea E. Prota, John E. Burke, Anna Melone, Alison J. Inglis, Ludovico Fusco, Vladimir Cmiljanovic, Natasa Cmiljanovic, Denise Rageot, Katja Bargsten, Gonzalo Saez-Calvo, Olivier Pertz, Amol B. Aher, Anna Akhmanova, Fernando J. Diaz, Doriano Fabbro, Marketa Zvelebil, Roger L. Williams, Michel O. Steinmetz, Matthias P. Wymann. BKM120-mediated G2 arrest: Structural and functional segregation of off-target action and PI3K inhibition. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 671. doi:10.1158/1538-7445.AM2015-671

[Imaging of acute brain inflammatory disease]

The central nervous system inflammatory disease can be due to any kind of infective agent (bacterial viral, fungal and parasitic), but entails also multiple sclerosis, a primary demyelinating disease in which the causal agent is unknown. MR imaging is, in most often, the procedure of choice, due to her multiplanar and multiparametric imaging, and to her better contrast resolution. The post-contrast imaging with double dose of gadolinium and late sequences enable visualisation of smallest pathologic foci or slightest blood-brain barrier alterations, with a sensibility very higher than post-contrast CT scan. In addition, RM provide to many functional informations, by means of diffusion, perfusion and spectroscopy studies, Bold technique for cortical activation studies and Fiber Tracking technique, in order to demonstrate pathologic modification earlier than they are evident on morphologic imaging. Functional imaging is also employed to monitor response to treatment and damage reversibility.

[Vertebral fractures: radiological diagnosis, differential diagnosis and prognostic implications]

Vertebral fractures are a relevant problem for the heavy clinical implications and carrying disability. Vertebral fractures can be traumatic or pathologic, the latter can be benign or malignant, both mostly frequent in the elderly. An initial approach to this issue can use plain radiographs, but the correct extension and evaluation must involve CT and MR imaging. In particular MR is a useful tool for the prognostic evaluation of spine marrow injuries and the differential diagnosis of osteoporotic and metastatic fractures.

[Child abuse: imaging of multiorgan damages]

An abused child can present with every lesion known to medicine, but some of these lesions can be specific of child abuse. The most frequent skeletal lesions are that of the long bones, of the head and the chest. Head damages are responsible for 80% of the dead in abused child. These kind of lesions are very important because they can produce important neurological deficits. Most frequent are extraxial bleeding and intraparenchimal lesions. Abdominal damages are the second cause of dead in the abused child. They can be asymptomatic and so they can be misdiagnosed. They are not so frequent but if they are present, they are letal. Conventional radiology, CT and MRI are very important in the management of child abuse because they allow to reveal multiorgan damages which, in some instances, can be specific of a child abuse.

[New CT and MR imaging techniques in non-traumatic neurological emergencies]

New CT and MR imaging techniques used for non-traumatic neurologic emergencies (represented mostly by ischemic stroke) fulfil the exigency to know quickly and with high accuracy the presence of abnormalities in cerebral perfusion, with the final aim to practise immediately all the treatments needed to prevent the progression of the neurologic damage, by selecting those patients to undergo fibrinolysis, which is useless and not indicated in many occasions. The diagnosis of ischemia is only the first goal reached by these new diagostic tools, while it is nowdays possible and required to stratify the risk factors for the therapy and to accurate select those patients candidates to fibrolnilysis, in order to minimize the risck related to the inadequate treatment choice.

[Neuroimaging of Alzheimer disease: current role and future potential]

Alzheimer disease (AD), the most common cause of dementia in the elderly, is a progressive neurodegenerative disorder, associated with deterioration in cognition and behaviour. With the availability of newer drugs for symptoms treatments there is a general agreement to the need of an early diagnosis and an the development of new sensitive tools, to identify and/or monitor early cerebral changes, suggestive for AD. CT and MRI are recommended for routine evaluation, in order to exclude treatable causes of dementia and to exactly evaluate the degree of cerebral atrophy and the presence of parenchymal signal abnormalities. Functional imaging, including PET, SPECT and functional MR techniques, are able to investigate physiological cerebral function, such as blood perfusion, metabolism, activation, molecular composition and water diffusibility, and have the potential to detect subtle pathological changes earlier during course of disease. MRI can provide both an accurate morphological assessment and a functional evaluation. Further investigations are needed to precisely define which will be the role of the different MR techniques. Most likely an exhaustive evaluation of AD will include information obtained by conventional and functional imaging, combined with clinical, laboratory and genetic findings.

[Role of magnetic resonance in shoulder disease]

Next to the knee, the shoulder is the most common joint to be referred for MRI. Excellent soft tissue contrast and multiplanar acquisition provide optimal assessment of muscle, tendons, hyaline and fibrous cartilage, joint capsule, fat, bursae and bone marrow. In this article the most common indications for shoulder MRI are reviewed and discussed, but we focused primarily on the rotator cuff syndrome and shoulder instability. Correct diagnosis requires the use of appropriate pulse sequences and imaging planes, proper patient positioning, and a satisfactory surface coil. Moreover, technical improvements continuously augment the ability of MRI to study the shoulder; for example Magnetic Resonance arthrography is superior to the other imaging techniques in evaluation of glenohumeral joint. This interdependence between technical development in MRI and clinical advance in shoulder therapy ensures that MRI will continue to play an important role in the routine management of patients with shoulder disease.

[The role of MRI in the diagnosis and evaluation of extension of the disease and condition of patients with neurofibromatosis]

Neurofibromatosis 1 (NF 1) and Neurofibromatosis 2 (NF 2) have been recently recognized to be distinct disorders through genetic linkages. MR imaging can be used to identify abnormalities of the head and spine in patients with these disorders. This review highlights some important but lesser known aspects of the two more common phakomatoses. The role of newer imaging technique such as contrast-enhanced MR imaging in the evaluation of these disorders also are discussed.

[Tumors of the nose, paranasal sinuses and facial bones: the role of computerized tomography and MRI in the assessment of the damage]

The authors examine the use of CT and MR comparatively in tumours of nose, paranasal sinuses and facial bones. Both CT and MR are much more useful to assess the real extent of the pathology than to give specific diagnose. The resolution of the images and the possibility of examining them on many different planes give evident advantage to MR as regards the evaluation of tumors in this region. Nevertheless, CT with bone algoritme gives better details about bone structure.

[Imaging technics in the evaluation of malformations, traumatic and expansive disorders of the orbital region]

In this paper the authors evaluate the usefulness of the new radiological techniques in the study of the orbital region. They describe the role of modern computerized imaging in the planning of their correction of malformative and traumatic diseases of the orbit. Furthermore, the authors evaluate the usefulness of US, CT, and MR imaging in the differential diagnosis of growing masses of the orbit.

[Magnetic resonance of the encephalon in 17 patients with ocular Behçet's disease]

Behçet's disease is a chronic relapsing disorder of unknown etiology characterized by oral aphthous ulcerations, uveitis, genital ulcerations and bone lesions. A variety of other signs including polyarthritis, vascular conditions (blood vessel occlusions and aneurysms), epididymitis, gastrointestinal, pulmonary and heart lesions may also occur. Central nervous system (CNS) involvement is reported in 10-49% of cases and it is the first symptom of the disease in 5% of subjects. The neuro-Behçet's syndrome may appear as a brainstem syndrome, meningoencephalitis and an organic confusional syndrome or dementia. Cranial hypertension, mostly related to cerebral venous thrombosis, is also present in neuro-Behçet's disease and its incidence is reported in up to 10% of Behçet's patients. MRI is reportedly the most sensitive neuroradiologic approach to detect the focal lesions related to neuro-Behçet's disease and several single cases or series of Behçet's patients with neurologic signs have been examined with MRI. We used MRI to investigate CNS involvement in Behçet's disease patients with and without previous neurologic signs. MRI was carried out on 17 patients with ocular Behçet's disease without neurologic symptoms to assess the possible subclinical involvement of the CNS. Cerebrospinal fluid spaces were enlarged in 8 patients and 5 patients exhibited cortical atrophy. PD and T2-weighted hypersignal foci were demonstrated in parietal, frontal, subcortical and periventricular white matter in 6 subjects. Neuroradiologic abnormalities were found only in the patients with complete disease and with the disease diagnosed more than 10 years earlier. Even though the pathogenesis of these neuroradiologic abnormalities and their correlation with Behçet's disease remain to be clarified, our study suggests the possibility of subclinical CNS involvement in these patients, which may affect the therapeutic approach and their prognosis.

[Tumors of the oral cavity, oropharynx and salivary glands. Role of TC and MRI in neoplasm staging]

MRI and CT have an important role in the study of neoplasms of oropharynx, oral cavity and salivary glands. They play an invaluable role in the diagnosis and in the evaluation of the tumor growth. Moreover MRI allows multiplanar studies with the advantage of a more sensitive evaluation of the extension of the lesions.

[The role of imaging technics in assessing laryngeal neoplasms]

In this work the most frequent malignant diseases of the larynx are been evaluated. The authors want to emphasize the importance of CT and MRI to perform a careful assessment of the disease to choose an adequate surgical therapy.

[Magnetic resonance in AIDS-related encephalopathy]

Fifty-eight patients with AIDS disease were studied with MR imaging in the aim of detecting the grade of brain involvement. The examinations were performed with a 1.5 Tesla magnet. Thirty-seven showed white matter lesion (63.5%), twenty-five patients showed cerebral atrophy (43%), in eight patients the MR appearance was consistent with toxoplasmosis infection (13.5%), two patients showed a linfoma (3.4%) and two patients micrococcosis (3.4%). Seventeen out of the thirty-seven patients with white matter disease showed focal well circumscribed lesion (46%), while twenty showed diffuse involvement. Between the twenty-five patients with cerebral atrophy, twelve showed a prevalence of the cortical involvement and eight a subcortical atrophy. In five patients a concomitant, cortical and subcortical atrophy was found. Between the eight patients with neurotoxolesion and two of them a widespread encephalitis picture. The MR appearance of the two limphomas was that of periventricular, space occupying, masses. In two patients with micrococcis a nodular aspect of leptomeningeal lesions was found.

[Role of CT and MR in the assessment of lumbar degenerative disk disease]

The application of CT and MR techniques for the evaluation of degenerative disease of lumbar disk is illustrated in this work. A critical review of the literature was done.

[Tumors of the temporal bone and the cerebellopontine angle. Diagnosis, characterization and assessment of extension by using imaging technics]

We discuss in this paper the reliability of neuroimaging techniques in the diagnosis of neoplastic masses of the posterior-lateral skull base. We also discuss the role of TC and MRI in the evaluation of the extension pattern of these masses.

[Role of CT and MRI in the evaluation of tumoral pathology in the rhinopharynx, the parapharyngeal space and the masticatory apparatus]

In this paper we discussed the usefulness of CT and MR imaging in the study of tumors of nasopharynx, paraphararyngeal space and masticatory space. We also stressed the role of the techniques in the characterization and in assessing the extension of these diseases.

[Neoplastic involvement of the cranial base. Role of computerized tomography and magnetic resonance]

We discussed in this paper the abilities and limits of CT Scan and MR Imaging in the diagnosis of skull base tumors. We stressed the role of computerized neuroimaging in the characterization and evaluation of the extension of these tumor masses involving the skull base.

[Characterization of hepatic neoplasms: contribution of magnetic resonance]

The reliability of MR imaging in the diagnosis and characterization of space occupying lesions affecting the liver are discussed in this study. We discuss the role of MR imaging in the diagnosis of these tumours and its advantages compared with other available techniques such as ultrasonography and CT. We also discuss the results of MR in the characterization of focal neoplastic masses.

[Focal lesions of the spleen: contribution of magnetic resonance imaging]

MR findings in the study of focal splenic pathology are discussed in this paper. MR examination of the spleen shows some technical limits in the diagnosis of masses affecting this organ. On the contrary, the introduction of new paramagnetic contrast agents, with organospecific affinity, will no doubt improve the diagnostic power of MR imaging, in order to gain more information about these diseases.

[Current role of computerized tomography and prospectives of the use of magnetic resonance in the diagnosis of aortic abdominal aneurysms and evaluation of their complications]

In this work we discussed the role of conventional radiology, ultrasonography (US), angiographic study, CT scan and MR imaging in the diagnosis of abdominal aortic aneurysms and their complications. US is the most suitable technique for screening and follow-up study of aortic aneurysms. Unfortunately it is not so reliable in the study of visceral arteries and in fat patients. Aortic angiography is the most useful method for the study of visceral arterial branches, but it does not show the phlogistic changes as well as the peripheral thrombotic alterations within the lesion. TC scan is also a useful technique in the study of aortic aneurysm, although it is not so accurate in detecting the visceral arterial branches. Finally, we think that MR imaging is the most reliable method for the diagnosis of aortic aneurysm. Movement artifact and lack of information due to the poor visualization of calcifications are still the principal limits of this technique.

[Characterization of space occupying masses in the diencephalic-hypothalamic region. MRI vs. TC]

All morphologic aspects of neoplastic and non neoplastic masses, arising from the diencephalic-hypothalamic region are discussed in this paper. We describe the densitometric characteristics on CT scan and the MRI appearance of masses affecting this region, both of benign lesions and malignant neoplastic masses. We describe separately masses arising from within the III ventricle and those of extraventricular origin and all semiotic findings of neuroradiological techniques of computed imaging.

[Diagnostic imaging in the evaluation of non-neoplastic space occupying pathology in the sellar and suprasellar region]

Before the introduction of computed imaging techniques like CT scan and MR, the differential diagnosis of lesions affecting the sellar and suprasellar regions was very difficult, more often impossible. These techniques contributed to ameliorate the typing of pathological tissues. Non neoplastic pathological findings of this region are very different and they can variate between phlogistic processes, vascular lesions, hamartomatous formations or congenital malformations. In this work we describe the characteristic changes of morphology and radiologic aspect in the diagnostic study of this region, using CT scan and MR imaging.

[Computerized tomography and magnetic resonance in the evaluation of neoplastic processes localized on the floor of the third ventricle]

In our experience, neoplastic lesions of the floor of the third ventricle are frequently responsible for neurologic and dysendocrine symptoms. Ct scan and MR imaging are the most reliable techniques of neuroimaging in the diagnostic study of neoplastic masses affecting this region. In this work, CT and MR appearance of lesions of the III ventricle floor are discussed with the aim of contributing to the differential diagnosis of neoplasms and their surgical and medical management.

[The role of tomography (X-ray and magnetic resonance) in the diagnosis and determination of the extension of tumors in the roof of the third ventricle]

We describe the CT scan and MR appearance of neoplastic lesions affecting the roof of the third ventricle. The neoplastic lesions of this region may be of neuroepithelial origin (sub-ependymoma, colloid cyst), meningeal cell origin (meningiomas), metastatic or primary localization of lymphoproliferative tumors (lymphomas) and dysembryogenetic origin (epidermoid tumor). CT scan and MR imaging are useful techniques for diagnosis and planning of surgical or medical treatment. The primary role of these imaging techniques, is discussed in the quantification of extension, biologic malignancy and anatomical relationships between pathologic lesion and normal nervous tissue.

[Aortic dissection: the role of diagnostic imaging, with special reference to magnetic resonance imaging and its implications in the pathogenesis]

The aim of this work was to evaluate the usefulness of angiography, CT scan and MR imaging in the diagnosis of aortic dissection, on the basis of the authors' experience and literature review. Angiographic study is still considered the first choice technique in the diagnosis of aortic dissection, although it is considered not completely safe. CT scan allows to note the early thickening of the vessel walls (due to intraparietal bleeding) and the presence of calcifications in the thrombosed portion of the lesion. MR study allows multiplanar study of the lesions without contrast medium, and best visualization of subendothelial bleeding in dissections without intimal lesion.

[Diagnostic imaging in the evaluation of masses developing in the cerebral ventricles]

CT scan and MR imaging of intraventricular masses are discussed in this work. The lesions affecting this region may be of neoplastic, vascular or phlogistic origin. CT scan and MR imaging are useful for diagnosis and management of these lesions. Intraventricular masses are well documented by high resolution CT scan after administration of endo-rachideal metrizamide, during ventriculographic studies. This technique gives important informations about peripheral relationship of intraventricular masses with increased liquoral fluid. MR imaging is also available for characterizing pathologic tissues, and for detecting the anatomic relationships between pathologic and normal structures.

[A comparison between computed tomography and magnetic resonance in the verification of prolactinomas]

First, computer tomography and subsequently magnetic resonance have profoundly changed the diagnostic protocol for the study pituitary pathology. Conventional X-ray and examination with the use of contrast media are being employed less and less. Tomographic techniques (CT and RM) permit direct identification of anomalies as well as precise evaluation of their relationship with surrounding structures.