New pharmacotherapy strategy for drug-resistant epilepsy

Epilepsy is one of the greatest therapeutic challenges in today's neurology. Unfortunately, despite the introduction of newer and newer preparations into treatment, as many as 30% of patients show resistance to pharmacotherapy (the so-called drug-resistant epilepsy). Hence, there is a need for new and alternative therapeutic strategies.

The proposed research corresponds with this direction. In recent years, in cooperation with
Epilepsy Therapy Screening Program (ETPS), we have discovered a series of pyridylacetamide derivatives, novel sodium channel blockers, with extensive activity in animal models of epilepsy (including drug-resistant epilepsy). As a development of this direction, we propose to enrich the in vivo activity profile of one of the most active pyridylacetamides (code name - ADD424042), through its chemical conjugation with another compound found in advanced research preclinical for epilepsy, glycogenesis inhibitor, 2-deoxy-d-glucose (2DG). Such a conjugate should have better anticonvulsant properties than either of the substances separately. This assumption is based on the fact that ADD424042 and 2DG have different mechanisms of action, and their profiles in in vivo studies are complementary (e.g. 2DG is not active in MES and scPTZ models, and is more effective than ADD424042 in drug-resistant kindle convulsions models). Therefore, we assume that a properly designed conjugate will interact with the molecular targets of both parent compounds, and that its pharmacological profile in in vivo tests will be additive or even amplified.

2DG is known to penetrate the brain in an active manner dependent on GLUT-type transporters. Expression of these
transporters is higher in areas where there is a high demand for energy (incl. areas of the brain affected by epileptic discharges), which suggests that the relationship will be selectively delivered to neurons with disturbed excitability and that it will stay in these cells trapped after phosphorylation by hexokinase. This may be relevant to ADD424042's effects as
a sodium channel modulator as the compound is likely to act intracellularly. The first stage of the project will be to obtain a properly designed conjugate. According to the SAR data of the ADD424042 analogs, the substituents on the amide nitrogen are tolerated. On the other hand, literature reports show that the acylated derivatives of 2-amino-2DG
are subject to active transport. The essence of the synthesis is the coupling of ADD424042 with 2-DG. For this, you will need to receive key ester 1 followed by its aminolysis with a linker, b-alanine tert-butyl ester. This process, catalyzed by the strong guanidine base, is chemoselective towards the methyl esters. We know from previous studies that aternative hydrolysis of compound 2 is not possible because it is simultaneously decoxylated. The next planned stage is deprotection
derivative 2 and conjugation of the released carboxyl group with the amine derivative of 2DG. The next step will be to determine the inhibitory activity of the glycolytic enzymes: isomerase glucosephate and hexokinase (test kits are commercially available). Both of these enzymes are inhibited by 2DG, while 2DG and 2-acylamino-2DG are known inhibitors heskokinases. The basic ADME profile will be determined: microsomal and plasma stability, plasma protein binding, logD, biological membrane permeability (Caco-2), susceptibility to P-glycoprotein-mediated release, inhibition of cytochrome P450 and hERG channel. Tests are required to submit an ETSP for the compound to be qualified for in vivo testing. After completing the project, the ability to modulate sodium currents will be tested, characterizing ADD424042. The described tests will help to determine the usefulness of the planned ones conjugates as compounds with in vivo activity in animal models of epilepsy; and examination under the ETSP. If a proof-of-concept is obtained, another one will be submitted as grant application, presenting a plan for optimization and further research on 2DG conjugates.