Classification of spinal cord arteriovenous shunts: Proposal for a reappraisal - The Bicêtre experience with 155 consecutive patients treated between 1981 and 1999

OBJECTIVE: Spinal cord arteriovenous shunts (SCAVSs) are currently classified according to their morphological features. Certain shunts cannot be fully integrated into the predetermined categories that are usually described, however. Can these classifications be reevaluated on the basis of recent anatomic, biological, and genetic advances? METHODS: We reviewed the clinical and radiological files for 155 SCAVSs that were treated at Hôpital Bicêtre between 1981 and 1999. The lesions were examined with respect to their number (single or multiple), their primary architectural type (nidus or fistula), and their possible links with associated metameric lesions. RESULTS: All SCAVSs were either arteriovenous malformations or fistulae, with the latter being either micro- or macrofistulae. All SCAVSs corresponded to three categories, i.e. genetic hereditary lesions (macrofistulae and hereditary hemorrhagic telangiectasia), genetic nonhereditary lesions (all of which were multiple lesions with metameric or myelomeric associations), and single lesions (which could represent incomplete presentations of one of the previous groups). Of the SCAVSs in our series, 81% were single lesions and 19% were multiple; among these, 59% were true intradural shunts with metameric features. Ten cases of Cobb syndrome, three cases of Klippel-Trenaunay syndrome, and two cases of Parkes-Weber syndrome, all with associated cord lesions, were observed. Nineteen percent of SCAVSs were fistulae; 23% of those were macrofistulae, of which 83% were related to Rendu-Osler-Weber disease. CONCLUSION: It seems legitimate to propose a categorization that takes into consideration a primary malformation (nidus or fistula) that evolves with time and in which angioarchitectural changes occur. Recognition of the factors originally responsible for the shunt (e.g. genetic hereditary or genetic nonhereditary) allows a different classification of SCAVSs.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Discovery of Umibecestat (CNP520): A Potent, Selective and Efficacious β-Secretase (BACE1) Inhibitor for the Prevention of Alzheimer’s Disease

Starting from lead compound 6, 5-amino-1,4-oxazine BACE1 inhibitors were optimised in order to improve potency, brain penetration and metabolic stability. Insertion of a Me and a CF3 group at the 6-position of the 5-amino-1,4-oxazine, led to 8 (NB-360) an inhibitor with a pKa of 7.1, a very low P-gp efflux ratio and excellent pharmacological profile enabling high CNS penetration and exposure. Fur color changes observed with NB-360 in efficacy studies in preclinical animal models triggered further optimization of the series. Herein, we describe the steps leading to the discovery of 3-chloro-5-trifluoromethyl-pyridine-2-carboxylic acid [6-((3R,6R)-5-amino-3,6-dimethyl-6-trifluoromethyl-3,6-dihydro-2H-[1,4]oxazin-3-yl)-5-fluoro-pyridin-2-yl]amide 15 (CNP520, umibecestat), an inhibitor with superior BACE1/BACE2 selectivity and pharmacokinetics. CNP520 reduced significantly Aβ levels in mice and rats in acute and chronic treatment regimen without any side effects and thus qualified for AD prevention studies in the clinic

Discovery of amino-1,4-oxazines as potent BACE-1 inhibitors

New amino-1,4-oxazine derived BACE-1 inhibitors were explored and various synthetic routes developed. The binding mode of the inhibitors was elucidated by co-crystallization of 4 with BACE-1 and X-ray analysis. Subsequent optimization led to inhibitors with low double digit nanomolar activity in a biochemical and single digit nanomolar potency in a cellular assays. To assess the inhibitors for their permeation properties and potential to cross the blood-brain-barrier a MDR1-MDCK cell model was successfully applied. Compound 8a confirmed the in vitro results by dose-dependently reducing Aβ levels in mice in an acute treatment regimen

Synthesis of the Potent, Selective, and Efficacious β-Secretase (BACE1) Inhibitor NB-360

Starting from lead compound 4, the 1,4-oxazine headgroup was optimized to improve potency and brain penetration. Focusing at the 6-position of the 5-amino-1,4-oxazine, the insertion of a Me and a CF3 group delivered an excellent pharmacological profile with a pKa of 7.1 and a very low P-gp efflux ratio enabling high central nervous system (CNS) penetration and exposure. Various synthetic routes to access BACE1 inhibitors bearing a 5-amino-6-methyl-6-(trifluoromethyl)-1,4-oxazine headgroup were investigated. Subsequent optimization of the P3 fragment provided the highly potent N-(3-((3R,6R)-5-amino-3,6-dimethyl-6-(trifluoromethyl)-3,6-dihydro-2H-1,4-oxazin-3-yl)-4-fluorophenyl)-5-cyano-3-methylpicolinamide 54 (NB-360), able to reduce significantly Aβ levels in mice, rats, and dogs in acute and chronic treatment regimens

Discovery of a selective and biologically active low-molecular weight antagonist of human interleukin-1β

Abstract Human interleukin-1β (hIL-1β) is a pro-inflammatory cytokine involved in many diseases. While hIL-1β directed antibodies have shown clinical benefit, an orally available low-molecular weight antagonist is still elusive, limiting the applications of hIL-1β-directed therapies. Here we describe the discovery of a low-molecular weight hIL-1β antagonist that blocks the interaction with the IL-1R1 receptor. Starting from a low affinity fragment-based screening hit 1, structure-based optimization resulted in a compound (S)-2 that binds and antagonizes hIL-1β with single-digit micromolar activity in biophysical, biochemical, and cellular assays. X-ray analysis reveals an allosteric mode of action that involves a hitherto unknown binding site in hIL-1β encompassing two loops involved in hIL-1R1/hIL-1β interactions. We show that residues of this binding site are part of a conformationally excited state of the mature cytokine. The compound antagonizes hIL-1β function in cells, including primary human fibroblasts, demonstrating the relevance of this discovery for future development of hIL-1β directed therapeutics

The BACE‐1 inhibitor CNP520 for prevention trials in Alzheimer's disease

Abstract The beta‐site amyloid precursor protein cleaving enzyme‐1 (BACE‐1) initiates the generation of amyloid‐β (Aβ), and the amyloid cascade leading to amyloid plaque deposition, neurodegeneration, and dementia in Alzheimer's disease (AD). Clinical failures of anti‐Aβ therapies in dementia stages suggest that treatment has to start in the early, asymptomatic disease states. The BACE‐1 inhibitor CNP520 has a selectivity, pharmacodynamics, and distribution profile suitable for AD prevention studies. CNP520 reduced brain and cerebrospinal fluid (CSF) Aβ in rats and dogs, and Aβ plaque deposition in APP‐transgenic mice. Animal toxicology studies of CNP520 demonstrated sufficient safety margins, with no signs of hair depigmentation, retina degeneration, liver toxicity, or cardiovascular effects. In healthy adults ≥ 60 years old, treatment with CNP520 was safe and well tolerated and resulted in robust and dose‐dependent Aβ reduction in the cerebrospinal fluid. Thus, long‐term, pivotal studies with CNP520 have been initiated in the Generation Program