Combination comprising at least one serotonin reuptake inhibitor and at least one stimulator of the potassium chloride cotransporter type 2, and medical uses thereof

Abstract

The present invention relates to a combination comprising at least one monoamine reuptake inhibitor and at least one potassium chloride cotransporter type 2 expression enhancing compound (KEEC). The present invention further relates to a pharmaceutical composition comprising at least one monoamine reuptake inhibitor and at least one KEEC, as well as to a kit of parts comprising at least one monoamine reuptake inhibitor and at least one KEEC as a combined preparation for simultaneous, separate or sequential use.

Description

[Technical field]

[0001] The present invention relates to a combination of active agents and their use in the treatment of pain sensations induced by peripheral neuropathy, inflammation or diabetes.

[0002] Thus, the present invention has utility in the medical field.

[0003] In the following description, references in square brackets ([]) refer to the list of references at the end of this document. [Background technology]

[0004] Pain is a warning system that protects the organism from actual or potential tissue damage. This unpleasant sensation can be efficiently filtered in cases of excessive pain thanks to the presence of an endogenous system that controls pain transmission. This endogenous system is activated in humans by diffuse inhibitory nociceptive modulation (DNIC), also called conditioned stimulus pain modulation (CPM). Deficits in CPM are valid predictors of poor pain outcomes after surgery, and there is growing evidence linking abnormal CPM to chronic pain states in patients with postoperative, neuropathic or idiopathic pain. In this context, CPM paradigms are used to evaluate pain states. Alterations in CPM seem to result from an imbalance between excitatory and inhibitory descending pain pathways involving monoaminergic nuclei (i.e., serotonin and noradrenaline) in the brainstem that project to the dorsal horn of the spinal cord (DH). So far, the underlying neural circuits remain largely unknown.

[0005] Therefore, the treatment of chronic neuropathic pain remains an important area of ​​research. In fact, current treatments have very modest efficacy. Of these treatments, the first line consists of tricyclic antidepressants (TCAs) and nonspecific serotonin and noradrenaline reuptake inhibitors (SNRIs). Unfortunately, these molecules alone provide interesting but still very unsatisfactory results. In fact, the latest data from the International Association for the Study of Pain (IASP) NeuPSIG (International Neuropathic Pain Expert Group) show that the number of treatments needed to halve pain in at least one patient is 3.6 for tricyclic antidepressants and 6.6 for SNRIs (NNT). These results were obtained after a meta-analysis of 229 placebo-controlled studies.

[0006] On the other hand, these uses of SNRIs resulted in significant side effects, with the number needed to stop treatment due to adverse side effects (NNH) being 13.4 for tricyclics and 11.8 for SNRIs (data published by Finnnerup et al. in Lancet neurology in 2016).

[0007] At the same time, research using molecules that specifically target serotonin (SSRIs) has little or no effect on pain levels in neuropathic patients, but has fewer side effects.

[0008] Therefore, there is a need for alternative, efficient and well-tolerated tools to treat chronic neuropathic pain. Summary of the Invention

[0009] The present invention meets these and other needs, and indeed the applicant has surprisingly discovered such an alternative solution for treating chronic pain.

[0010] The applicant has surprisingly shown that increasing serotonin levels in the spinal cord is beneficial in neuropathic pain states when combined with a KCC2 type chloride transporter activator.

[0011] In particular, applicants have demonstrated in vivo superior efficacy of combination treatment with serotonin reuptake inhibitors, also referred to as "monoamine transporter inhibitors," or monoamine reuptake inhibitors, including SSRIs, SNRIs, SMSs, SNDRIs, and TCAs, and enhancers of KCC2-type chloride transporters, also referred to as KCC2 expression enhancing compounds ("KEECs"), in neuropathic mice, compared to treatment with serotonin reuptake inhibitors (i.e., "MRI") alone or with KCC2-type chloride transporter activators (i.e., "KEEC") alone. In particular, the combination of fluoxetine, a selective serotonin reuptake inhibitor, injected intraperitoneally by gavage (orally), and CLP290, a KCC2-type chloride transporter activator, resulted in an increase in mechanical threshold response that was maintained for at least 24 hours after injection in a model of neuropathic pain, as demonstrated by applicants. The fluoxetine / CLP combination resulted in a significant improvement in mechanical response threshold that was significantly higher than fluoxetine and CLP alone.

[0012] The applicant also compared the efficacy of a combination of a serotonin reuptake inhibitor, particularly a SSRI, and a KCC2 chloride transporter activator (also called KEEC) in the conditioned place preference (CPP) test. The applicant showed that this combination increases the time that animals spend in the treatment compartment, but this time is not modified by the combination of a serotonin reuptake inhibitor (particularly a SSRI) / vehicle. The results show that the combination of a serotonin reuptake inhibitor / KCC2 chloride transporter activator leads to an improvement in the general condition of the animals, reinforcing the results obtained in terms of mechanical response threshold.

[0013] Finally, the Applicant has obtained surprising results with combinations of SSRIs with various KEECs (CLP657, a piperazine phenothiazine, prochlorperazine (PCPZ), an ATP-competitive inhibitor of glycogen synthase kinase 3 beta (Kenpaullone)) and with combinations including CLP290 and MRI (in particular an SSRI as paroxetine, an SNRI as duloxetine, or a TCA as amitriptyline).

[0014] Thus, in a first aspect, the present invention provides a combination comprising at least one serotonin reuptake inhibitor (also called a "monoamine reuptake inhibitor") and at least one enhancer of the potassium chloride cotransporter type 2 (KCC2).

[0015] "Serotonin reuptake inhibitors" and its synonym "monoamine reuptake inhibitors," as used herein, refer to any compound, drug, active agent, or pharma- ceutically acceptable salt thereof, that acts by inhibiting the neuronal reuptake of the neurotransmitter serotonin, thus increasing serotonin levels and serotonergic neurotransmission in the brain and spinal cord. Examples of serotonin reuptake inhibitors (SRIs) are given in the literature: "NICE Clinical Guidelines, No.31. National Collaborating Centre for Mental Health (UK). Leicester (UK): British Psychological Society (UK); 2006" ([8]), Grunder et al. ([9]), Moses-Kolko et al. (

[10] ), Hughes ZA, Starr KR, Langmead CJ, et al. Neurochemical evaluation of the novel 5-HT1A receptor partial agonist / serotonin reuptake inhibitor, vilazodone. Eur J Pharmacol 2005; 510(1-2): 49-5 (

[11] ), Bartoszyk et al. (

[12] ) and Gerald P. Koocher et al. (

[13] ). The serotonin reuptake inhibitor is advantageously a serotonin-specific reuptake inhibitor (SSRI), a serotonin-specific inhibitor. It may be selected from the group consisting of serotonin modulators and stimulants (SMS), serotonin, norepinephrine and dopamine reuptake inhibitors (SNDRI), serotonin noradrenaline reuptake inhibitors (SNRI) and tricyclic antidepressants (TCA).Preferably, the serotonin reuptake inhibitor may be SSRI or SMS.In this case, the SSRI or SMS may be selected from fluoxetine, paroxetine, sertraline, citalopram, escitalopram oxalate, indalpine, zimelidine, vilazodone, dapoxetine, vortioxetine and fluvoxamine maleate.Preferably, it may be fluoxetine.When the serotonin reuptake inhibitor is an SNRI, it may be selected from desvenlafaxine, duloxetine, levomilnacipran, milnacipran and venlafaxine. If the serotonin reuptake inhibitor is a TCA, it may be selected from amitriptyline, amoxapine, desipramine, doxepin, imipramine, nortriptyline, protriptyline and trimipramine.If the serotonin reuptake inhibitor is an SNDRI, it may be selected from sibutramine, mazindol and nefazodone.

[0016] "Stimulator of potassium chloride cotransporter type 2" or "KCC2", or its synonyms "potassium chloride cotransporter type 2 enhancer", "KCC2 expression enhancing compound" or "KEEC" refers to any compound, drug, active agent, or pharma- ceutically acceptable salt thereof, that can increase KCC2 expression, activity, or function and decrease the intracellular concentration of chloride ions. The stimulator of the potassium chloride cotransporter type 2 may advantageously be selected from the group consisting of molecules of the CLP family that increase the number of KCC2-type chloride transporters in the membrane of spinal cord neurons, antipsychotic molecules of piperazine phenothiazines, and ATP-competitive inhibitors of glycogen synthase kinase 3 beta, other molecules that have such activity in particular by acting via inhibition of fms-like tyrosine kinase 3 (FLT3), or tropomyosin / tyrosine receptor kinase B (TrkB), or phosphodiesterase 1 (PDE1), or via activation of the sirtuin 1 (SIRT1) or transient receptor potential cation channel subfamily V member 1 (TRPV1) pathway, or via any other mechanism that leads to an increase in KCC2. The molecules of the CLP family may be selected, for example, from CLP 290, CLP257 and CLP657. The antipsychotic molecule of the piperazine phenothiazine family may be prochlorperazine. Glycogen synthase kinase 3 ATP-competitive inhibitors of β are, for example, Kenpaullone, BIO (6-bromoindirubin-3'-oxime), TWS-119 (3-[6-(3-aminophenyl)-7H-pyrrolo[2,3-d]pyrimidin-4-yloxy]-phenol), indirubin monoxime (3-[1,3-dihydro-3-(hydroxyimino)-2H-indol-2-ylidene]-1,3-dihydro-2H-indol-2-one), indirubin ( (3Z)-3-(3-oxo-1,3-dihydro-2H-indol-2-ylidene)-1,3-dihydro-2H-indol-2-one), AR-A014418 (N-(4-methoxybenzyl)-N'-(5-nitro-1,3-thiazol-2-yl)urea), SB-415286 (3-[(3-chloro-4-hydroxyphenyl)-amino]-4-(2-nitrophenyl)-1H-pyrrole-2,5-dione).Examples of FLT3 inhibitors include KW-2449 ((E)-(4-(2-(1H-indazol-3-yl)vinyl)phenyl)(piperazin-1-yl)methanone), crenolanib (1-(2-{5-[(3-methyloxetan-3-yl)methoxy]-1H-benzimidazol-1-yl}quinolin-8-yl)piperidin-4-amine), XL-184 (cabozantinib; N-(4-((6,7-dimethoxyquinolin-4-yl)oxy)phenyl)methanone), dovitinib (1-amino-5-fluoro-3-(6-(4-methylpiperazin-1-yl)-1H-benzo[d]imidazol-2-yl)quinolin-2(1H)-one), FLT inhibitor-1 (Calbiochem 343020; 2-(3,4-dimethoxybenzamido)-5,6-dihydro-4H-cyclopenta[b]thiophene-3-carboxamide), BMS 777607 (N-(4-(2-amino-3-chloropyridin-4-yloxy)-3-fluorophenyl)-4-ethoxy. -1-(4-fluorophenyl)-2-oxo-1,2-dihydropyridine-3-carboxamide) and sunitinib (N-[2-(diethylamino)ethyl]-5-[(Z)-(5-fluoro-1,2-dihydro-2-oxo-3H-indol-3-ylidene)-methyl]-2,4-dimethyl-1H-pyrrole-3-carboxamide).

[0017] The TrkB inhibitor can be 7,8-dihydroxy-flavone (7,8-dihydroxyflavone). The phosphodiesterase 1 (PDE1) inhibitor can be 8-methoxy-methyl-IBMX (8-(methoxymethyl)-1-methyl-3-(2-methylpropyl)-7H-purine-2,6-dione). The SIRT1 signaling pathway activator can be selected from, for example, resveratrol (3,5,4'-trihydroxy-trans-stilbene), kaempferol (3,5,7-trihydroxy-2-(4-hydroxyphenyl)-4H-chromen-4-one). The TRPV1 signaling pathway activator can be piperine ((2E,4E)-5-(benzo[d][1,3]dioxol-5-yl)-1-(piperidin-1-yl)penta-2,4-dien-1-one). Other mechanisms leading to an increase in KCC2 include kinase inhibitors such as SU-4312 (3-(4-dimethylaminobenzylidenyl)-2-indolinone, 3-[[(4-dimethylamino)phenyl]methylene]-1,3-dihydro-2H-indol-2-one), monoamine oxidase inhibitors-B such as safinamide, paxillin ((2R,4bS,6aS,12bS,12cR,14aS)-5,6,6a,7,12,12b,12c,13,14,14a-decahydro-4bhydroxy-2-(1-hydroxy-1-methylethyl)-12b,12c-dimethyl- and potassium channel blockers such as 2H-pyrano[2”,3”:5’,6’]benz[1’,2’:6,7)indeno[1,2-b]indol-3(4bH)-one); atypical antipsychotics such as paliperidone (9-hydroxyrisperidone); kava extracts such as the kavalactone methisin ((2R)-2-[(E)-2-(1,3-benzodioxol-5-yl)ethenyl]-4-methoxy-2,3-dihydropyran-6-one); and ATP-competitive inhibitors of tyrosine kinases including Flt-1, Flt-4, Met and Ron, such as foretinib.

[0018] Advantageously, in the combination, the at least one serotonin reuptake inhibitor (or monoamine reuptake inhibitor) is fluoxetine, paroxetine, duloxetine, amitriptyline and the at least one KCC2 stimulator (or KCC2 expression enhancing compound) is CLP 290, CLP657, PCPZ or Kenpaullone.

[0019] "Combination" as used herein refers to a formulation in which at least one serotonin reuptake inhibitor and at least one KCC2 stimulator exhibit synergistic effects in reducing pain sensation induced by peripheral neuropathy, inflammation, or diabetes, either in vitro or in vivo. The term "synergism" or "synergistic" as used herein refers to a therapeutic combination that is more effective than the additive effects of two single active agents, i.e., at least one serotonin reuptake inhibitor (also called "monoamine reuptake inhibitor"), at least one KCC2 stimulator (also called KCC2 expression enhancing compound). The determination of synergistic interactions between at least one serotonin reuptake inhibitor and at least one KCC2 stimulator may be based on the results obtained from the assays described herein. The results of these assays may be analyzed using a simplified up-and-down method for mechanical pain threshold assays and a tracking system for conditioned place preference assays. The combinations provided by the present invention have been evaluated in several assay systems, and the data can be analyzed using standard programs to quantify synergy, additivity, and antagonism between drugs.

[0020] According to the present invention, a synergistic effect occurs when the active agents are (1) co-formulated and administered or delivered simultaneously in a combined unit dosage formulation, or (2) delivered as separate formulations. , can be achieved. When delivered in separate formulations, synergistic effects can be achieved when the compounds are administered or delivered simultaneously or sequentially, for example by different injections in separate syringes. In this case, the combination may be administered in two or more doses, for example by sequential administration in any order, preferably with a period during which both (or all) active agents simultaneously exert their biological activity. Whether by co-administration or by a simultaneous, separate or sequential regimen, a therapeutically effective amount of each active ingredient is administered. Advantageously, the synergistic effect of the combination of the present invention allows to improve pain sensation and / or symptoms from the very first administration of the combination, regardless of whether it is simultaneous, separate or sequential administration. Advantageously, the effect of the combination is very fast or even immediate. Moreover, advantageously, the therapeutic effect can last for at least 4 hours, and up to at least 24 hours. In other words, advantageously, in some embodiments, a single dose of the combination can be sufficient to eliminate pain and reduce the administered dose to limit adverse side effects.

[0021] The combination of the present invention may comprise a therapeutically effective amount of at least one serotonin reuptake inhibitor (also called "monoamine reuptake inhibitor") and a therapeutically effective amount of at least one KCC2 stimulator (also called KCC2 expression enhancing compound). The phrase "therapeutically effective amount" refers to an amount of a compound of the present invention that (i) treats a particular disease, condition, or disorder, (ii) attenuates, improves, or eliminates one or more symptoms of a particular disease, condition, or disorder, or (iii) prevents or delays the onset of one or more symptoms of a particular disease, condition, or disorder described herein. In the case of treating pain sensation induced by peripheral neuropathy, inflammation, or diabetes, a therapeutically effective amount of the above-mentioned active agent may reduce mechanical allodynia by about 52% (38% to 101%) 1 hour and 30 minutes after injection, and still by about 36% (23% to 65%) 24 hours after injection. As an example, the pharmacologic effective amount of a serotonin reuptake inhibitor (also called a "monoamine reuptake inhibitor") administered per dose ranges from about 0.1 to 10 mg / kg, depending on the route of administration, i.e., about 20 mg (1 tablet) per day, with a typical initial range of the compound used being 20 to 60 mg / day (i.e., a dose of about 0.3 mg / kg / day for a 70 kg adult). Also as an example, the pharmacologic effective amount of a stimulator of KCC2 (also called a KCC2 expression enhancing compound) administered per dose ranges from about 10 to 100 mg / kg, depending on the route of administration, i.e., about 10 to 100 mg per kg of patient body weight per day, with a typical initial range of the compound used being 10 to 100 mg / kg / day.

[0022] According to the present invention, "at least one" refers to one, or two, or three, or four, or more of the mentioned active agents.

[0023] Another object of the present invention relates to a pharmaceutical composition comprising at least one serotonin reuptake inhibitor (also called "monoamine reuptake inhibitor") and at least one stimulator of potassium chloride cotransporter type 2 (KCC2) (also called KCC2 expression enhancing compound). The at least one serotonin reuptake inhibitor and the at least one KCC2 stimulator, as well as their therapeutically effective amounts, are as defined above.

[0024] Serotonin reuptake inhibitors (also referred to as monoamine reuptake inhibitors) and stimulators of KCC2 (also referred to as KCC2 expression enhancing compounds) may be formulated into pharmaceutical compositions according to standard pharmaceutical practice for use in therapeutic treatments in mammals, including humans. Thus, the pharmaceutical compositions of the present invention include a combination of the above-mentioned active agents with one or more pharma- ceutically acceptable carriers, diluents, or excipients. The phrase "pharma-ceutically acceptable" indicates that a substance or composition must be chemically and / or toxicologically compatible with the other components of the formulation and with the mammal being treated therewith. Suitable carriers, diluents, and excipients are well known to those skilled in the art and include materials such as carbohydrates, waxes, water-soluble and / or swellable polymers, hydrophilic or hydrophobic materials, gelatin, oils, solvents, water, and the like. Solvents may be one or more of the following: Generally, the solvent is selected based on those recognized by those skilled in the art as being safe (GRAS) for administration to mammals. Generally, safe solvents are non-toxic aqueous solvents, such as water and other non-toxic solvents that are soluble or miscible in water. Suitable aqueous solvents include water, saline, cyclodextrin, ethanol, propylene glycol, polyethylene glycol (e.g., PEG 400, PEG 300), and the like, and mixtures thereof. The formulation may also include one or more buffers, stabilizers, surfactants, wetting agents, lubricants, emulsifiers, suspending agents, preservatives, antioxidants, opacifiers, glidants, processing aids, colorants, sweeteners, fragrances, and flavoring agents.

[0025] The pharmaceutical compositions of the invention can be prepared using conventional dissolution and mixing procedures. For example, the bulk drug substance can be dissolved in a suitable solvent in the presence of one or more of the excipients described above.

[0026] The pharmaceutical composition of the present invention can be administered by any route suitable for the condition to be treated, including oral and parenteral routes, the latter including subcutaneous, intramuscular, intravenous, intraarterial, intradermal, intrathecal, epidural, and infusion techniques. It is understood that the preferred route may vary, for example, depending on the condition of the recipient. When the composition is administered orally, it can be formulated as a tablet, pill, hard or soft capsule, such as a gelatin capsule, cachet, troche, lozenge, aqueous or oily suspension, dispersible powder or granule, emulsion, syrup, or elixir, each containing a predetermined amount of each active agent together with a pharma-ceutically acceptable carrier, glidant, or excipient. When the composition is administered parenterally, it can be formulated in a unit dosage injectable form together with a pharma-ceutically acceptable parenteral vehicle or diluent, as detailed below. For example, formulations suitable for parenteral administration include aqueous and non-aqueous sterile injection solutions which may contain antioxidants, buffers, bacteriostats, and solutes which render the formulation isotonic with the blood of the intended recipient; and aqueous and non-aqueous sterile suspensions which may include suspending agents and thickening agents.

[0027] Another object of the invention relates to a kit of parts comprising at least one serotonin reuptake inhibitor (also called monoamine reuptake inhibitor) as defined above and at least one stimulator of potassium chloride cotransporter type 2 (KCC2, also called KCC2 expression enhancing compound) as a combined preparation for simultaneous, separate or sequential use. All definitions given above are likely to apply mutatis mutandis to the kit of parts of the invention.

[0028] The "kit" according to the present invention may be provided as a product containing active agents useful for the treatment of the above diseases and disorders. The kit may include one container per active agent, or one container containing all active agents. The kit may further include a label or package insert on or associated with the container. The term "package insert" is used to refer to instructions customarily included in commercial packages of therapeutic products, including information on instructions for administration, indications, usage, dosage, management, contraindications and / or warnings regarding the use of such therapeutic products. In particular, when the kit includes a first formulation containing a serotonin reuptake inhibitor (also called a monoamine reuptake inhibitor) and a second formulation containing a KCC2 stimulator (also called a KCC2 expression enhancing compound), the kit may further include instructions for simultaneous, sequential or separate administration of the two formulations to a patient in need thereof.

[0029] Another object of the invention relates to a combination as defined above, to a pharmaceutical composition as defined above, or to a kit of parts as defined above, for medical use.

[0030] More specifically, the medical use may be the treatment of pain sensations induced by peripheral neuropathy, by inflammation or by diabetes.

[0031] The present invention is illustrated by the following examples with reference to the accompanying drawings, which should not be construed as limiting. This is further explained below. [Brief description of the drawings]

[0032] [Figure 1A]Reversal of mechanical allodynia by association of the KCC2 potentiator, CLP290, and the serotonin-specific reuptake inhibitor, fluoxetine. A) Von Frey filaments are used to assess the mechanical withdrawal threshold. Values ​​in grams (g) are the force required to induce paw withdrawal. Mechanical thresholds (in g) were assessed in naïve, SNI ("saline"), SNI (spinal nerve injury) groups injected intraperitoneally with 10 mg / kg fluoxetine, SNI injected by gavage with 100 mg / kg CLP290, and SNI injected with both fluoxetine and CLP290 of mice. SNI treatment induces a decrease in the mechanical threshold, indicative of mechanical allodynia. Treatment with CLP290 and fluoxetine reduced this allodynia, as the mechanical thresholds were not significantly different from naïve animals. [Figure 1B] Figure 1 shows reversal of mechanical allodynia by the association of the KCC2 potentiator, CLP290, and the serotonin-specific reuptake inhibitor, fluoxetine. B) Reduction of mechanical allodynia (in %) following treatment with fluoxetine, CLP290, and the association of both molecules. The association of CLP290 with fluoxetine reduced the amplitude of mechanical allodynia by 51.8%. [Figure 1C] Figure 2 shows reversal of mechanical allodynia by association of the KCC2 potentiator, CLP290, and the serotonin-specific reuptake inhibitor, fluoxetine. C) The combination of fluoxetine and CLP290 induces a reduction in mechanical allodynia 1 hour 30 minutes after one single injection, which lasts for at least 24 hours. [Diagram 2]Represents conditioned place preference (CPP). Neuropathic mice are allowed to freely explore the two-chamber arena. An association of CLP290 and fluoxetine (closed circle) is injected, and 1 hour and 30 minutes after injection, the neuropathic animals are blocked in the cued chamber. The next day, the mice are allowed to freely explore the two-chamber arena again. As a control experiment, the same procedure is performed in neuropathic mice with fluoxetine and CLP290 vehicle. Both associations of fluoxetine and CLP290 increase the time (in seconds) spent by neuropathic mice in the conditioned chamber, but fluoxetine alone does not (open circle). This preference for the compartment associated with our molecular formula is associated with the increased "health" associated with the association of the present invention. [Figure 3A] A) Reversal of mechanical allodynia by association of KCC2 potentiators and fluoxetine. Reduction of mechanical allodynia (in %) following treatment with CLP657, PCPZ and Kenpaullone alone, or in combination with either fluoxetine and CLP657, fluoxetine and PCPZ, or fluoxetine and Kenpaullone. [Figure 3B] B) Reversal of mechanical allodynia by association of CLP290 with an SSRI (paroxetine), a SNRI (duloxetine) or a TCA (amitriptyline). Reduction in mechanical allodynia (in %) following treatment with paroxetine, duloxetine or amitriptyline alone or in combination with either paroxetine and CLP290, either duloxetine and CLP290 or either amitriptyline and CLP290. EXAMPLES

[0033] Example 1: Reversal of mechanical allodynia by association of the KCC2 potentiator, CLP290, and the serotonin-specific reuptake inhibitor, fluoxetine In Figure 1A and B, mice are divided into five experimental groups: 1) a naïve group that receives only mechanical threshold assessment (in g). 2) the SNI (spinal nerve injury) group undergoes unilateral ligation and sectioning of two of the three main branches of the right sciatic nerve. Fourteen days after the surgical procedure, mechanical thresholds (in g) were assessed in the SNI group, the SNI group injected intraperitoneally with fluoxetine 10 mg / kg, the SNI group injected by gavage with CLP290 100 mg / kg, and the SNI group injected by gavage with fluoxetine 10 mg / kg. The results are evaluated in a group of SNIs injected with both poliovirus and CLP290.

[0034] Mechanical evaluation is performed for 1 hour and 30 minutes along with drug injection.

[0035] The mechanical withdrawal threshold is assessed using Von Frey filaments. The value in grams (g) is the force required to induce paw withdrawal (see FIG. 1A). SNI treatment induces a decrease in the mechanical threshold indicating mechanical allodynia. Treatment with CLP290 and fluoxetine reduced this allodynia, as the mechanical threshold was not significantly different from naive animals.

[0036] FIG. 1B) shows the percentage of reduced mechanical allodynia following treatment with fluoxetine, CLP290 and the association of both molecules. The association of CLP290 with fluoxetine reduced the amplitude of mechanical allodynia by 51.8%.

[0037] 3) Mechanical thresholds are assessed over 48 hours following injection of fluoxetine and CLP290.

[0038] Example 2: Conditioned Place Preference (CPP) Test Spinal nerve injury is performed as in Example 1.

[0039] After 14 days, the mice are free to explore a two-chamber arena separated by a narrow corridor for 10 min. A camera placed above the apparatus allows tracking of the mouse's movements. This investigation is considered the pretreatment condition in Figure 2. One hour and 30 min after injection with either fluoxetine alone or the combination of fluoxetine and CLP290, the mice are restricted to one chamber for 10 min. After 2 days, the mice are placed again and allowed to freely explore the entire arena. If the treatment improved the "health" of the mice, they will spend more time in the chamber associated with the treatment. This happened with the combination of CLP290 and fluoxetine, but not with fluoxetine alone (Figure 2). As a control experiment, the same procedure is performed in neuropathic mice with fluoxetine and CLP290 vehicle.

[0040] Thus, the association of both fluoxetine and CLP290, but not fluoxetine alone, increases the time spent by neuropathic mice in the conditioned chamber. This preference for the compartment associated with the molecular formula of the present invention is associated with an increase in "health" associated with this molecular formula.

[0041] Example 3: Reversal of mechanical allodynia by association of KCC2 potentiators and fluoxetine In Figure 3A and B, mice are divided into 12 experimental groups that undergo unilateral ligation and sectioning of two of the three main branches of the right sciatic nerve. 1) 14 days after the surgical procedure, in three groups, the percentage of allodynia is evaluated in SNI mice that received CLP657, PCPZ or Kenpaullone alone. In three other groups, the percentage of allodynia is evaluated in SNI mice that received fluoxetine (intraperitoneal, 10 mg / kg) and CLP657 (orally, 100 mg / kg), fluoxetine (intraperitoneal, 10 mg / kg) and PCPZ (intraperitoneal, 2 mg / kg) or fluoxetine (intraperitoneal, 10 mg / kg) and Kenpaullone (intraperitoneal, 10 mg / kg) alone. 2) In three other groups, mice receive paroxetine (SSRI, intraperitoneally, 10 mg / kg), duloxetine (SNRI, intraperitoneally, 10 mg / kg), or amitriptyline (TCA, intraperitoneally, 10 mg / kg) alone. In three other groups, mice receive a combination of paroxetine (i.p., 10 mg / kg) and CLP290 (orally, 100 mg / kg), or duloxetine (i.p., 10 mg / kg) and CLP290 (orally, 100 mg / kg), or amitriptyline (i.p., 10 mg / kg) and CLP290 (orally, 100 mg / kg). In all conditions, mechanical assessment is performed 1 hour and 30 minutes after drug injection.

[0042] Reference List 1. Rosenberg MB, Carroll FI, Negus SS. Effects of monoamine reuptake inhibitors in assays of acute pain-stimulated and pain-depressed behavior in rats. J Pain. 2013 Mar; 14 (3): 246-59. 2. Trepl J, Dahlmanns M, Kornhuber J, Groemer TW, Dahlmanns JK. Common network effect-patterns after monoamine reuptake inhibition in dissociated hippocampus cultures. J Neural Transm(Vienna). 2022 Mar; 129 (3): 261-275. 3. Lucas MC, Weikert RJ, Carter DS, Cai HY, Greenhouse R, Iyer PS, Lin CJ, Lee EK, Madera AM, Moore A, Ozboya K, Schoenfeld RC, Steiner S, Zhai Y, Lynch SM. Design, synthesis, and biological evaluation of new monoamine reuptake inhibitors with potential therapeutic utility in depression and pain. Bioorg Med Chem Lett. 2010 Sep 15; 20 (18): 5559-66. 4. Kearns B, Cooper K, Orr M, Essat M, Hamilton J, Cantrell A. The Incidence and Costs of Adverse Events Associated with Antidepressants: Results from a Systematic Review, Network Meta-Analysis and Multi-Country Economic Model. Neuropsychiatr Dis Treat. 2022 Jun 7; 18:1133-1143.doi: 10.2147 / NDT.S356414.PMID: 35698594; PMCID: PMC9188369. 5. Tang X, Drotar J, Li K, Clairmont CD, Brumm AS, Sullins AJ, Wu H, Liu XS, Wang J, Gray NS, Sur M, Jaenisch R. Pharmacological enhancement of KCC2 gene expression exerts therapeutic effects on human Rett syndrome neurons and Mecp2 mutant mice. Sci Transl Med. 2019 Jul 31; 11 (503) 6. Gagnon M, Bergeron MJ, Lavertu G, Castonguay A, Tripathy S, Bonin RP, Perez-Sanchez J, Boudreau D, Wang B, Dumas L, Valade I, Bachand K, Jacob-Wagner M, Tardif C, Kianicka I, Isenring P, Attardo G, Coull JA, De Koninck Y. Chloride extrusion enhancers as novel therapeutics for neurological diseases. Nat Med. 2013 Nov; 19 (11): 1524-8. 7. Serranilla M, Woodin MA. Striatal Chloride Dysregulation and Impaired GABAergic Signaling Due to Cation-Chloride Cotransporter Dysfunction in Huntington’s Disease. Front Cell Neurosci. 2022 Jan 14; 15: 817013.doi: 10.3389 / fncel. 2021. 817013. Erratum in: Front Cell Neurosci. 2022 Mar 11; 16: 876821. 8. NICE Clinical Guidelines, No.31. National Collaborating Centre for Mental Health (UK). Leicester (UK): British Psychological Society (UK); 2006. 9. Grunder G, Hiemke C, Paulzen M, Veselinovic T, Vernaleken I (2011). “Therapeutic plasma concentrations of antidepressants and antipsychotics: lessons from PET imaging”. Pharmacopsychiatry. 44(6): 236-48. 10. Moses-Kolko EL, Bogen D, Perel J, et al. Neonatal Signs After Late In Utero Exposure to Serotonin Reuptake Inhibitors: Literature Review and Implications for Clinical Applications. JAMA. 2005; 293 (19): 2372-2383. 11. Hughes ZA, Starr KR, Langmead CJ, et al. Neurochemical evaluation of the novel 5-HT1A receptor partial agonist / serotonin reuptake inhibitor, vilazodone. Eur J Pharmacol 2005: 510 (1-2): 49-5. 12. Bartoszyk et al., 1997 G. D. Bartoszyk, R. Hegenbart, H. Ziegler EMD 68843, a serotonin reuptake inhibitor with selective presynaptic 5-HT1A receptor agonistic properties Eur. J. Pharmacol., 322 (1997), pp.147-153. 13. Gerald P. Koocher; John C.Norcross; Beverly A. Greene (2013). Psychologists ’ Desk Reference. Oxford University Press. pp.407. ISBN 978-0-19-984550-7.

Claims

1. A combination comprising at least one monoamine reuptake inhibitor and at least one potassium chloride cotransporter type 2 expression enhancing compound (KEEC).

2. The combination according to claim 1, wherein the monoamine reuptake inhibitor is selected from the group consisting of a serotonin specific reuptake inhibitor (SSRI), a serotonin norepinephrine reuptake inhibitor (SNRI), and a tricyclic antidepressant (TCA).

3. The combination according to claim 2, wherein the SSRI is fluoxetine or paroxetine.

4. The combination according to claim 2, wherein the SNRI is duloxetine.

5. The combination according to claim 2, wherein the TCA is amitriptyline.

6. The combination according to any one of claims 1 to 5, wherein the KEEC is selected from the group consisting of a molecule of the CLP family, an antipsychotic molecule of the piperazine phenothiazine family, an ATP competitive inhibitor of glycogen synthase kinase 3β, and a molecule acting via inhibition of fms-like tyrosine kinase 3 (FLT3), tropomyosin / tyrosine receptor kinase B (TrkB), or phosphodiesterase 1 (PDE1), or via activation of the sirtuin 1 (SIRT1) or transient receptor potential cation channel subfamily V member 1 (TRPV1) pathway.

7. The combination according to claim 6, wherein the molecule of the CLP family is selected from CLP290, CLP257, and CLP657 The combination according to claim 6.

8. The combination according to claim 6, wherein the antipsychotic molecule of the piperazine phenothiazine family is prochlorperazine (PCPZ).

9. The combination according to claim 6, wherein the ATP competitive inhibitor of glycogen synthase kinase 3β is kenpaullone.

10. Wherein the at least one monoamine reuptake inhibitor is fluoxetine and the at least one KEEC is CLP 290, Wherein the at least one monoamine reuptake inhibitor is fluoxetine and the at least one KEEC is CLP 257, Wherein the at least one monoamine reuptake inhibitor is fluoxetine and the at least one KEEC is CLP 657, The at least one monoamine reuptake inhibitor is fluoxetine, and the at least one KEEC is PCZP. The at least one monoamine reuptake inhibitor is fluoxetine, and the at least one KEEC is camazepam. The at least one monoamine reuptake inhibitor is paroxetine, and the at least one KEEC is CLP 290. The at least one monoamine reuptake inhibitor is paroxetine, and the at least one KEEC is CLP 257. The at least one monoamine reuptake inhibitor is paroxetine, and the at least one KEEC is CLP 657. The at least one monoamine reuptake inhibitor is duloxetine, and the at least one KEEC is CLP 290. The at least one monoamine reuptake inhibitor is duloxetine, and the at least one KEEC is CLP 257. The at least one monoamine reuptake inhibitor is duloxetine, and the at least one KEEC is CLP 657. The at least one monoamine reuptake inhibitor is amitriptyline, and the at least one KEEC is CLP 290. The at least one monoamine reuptake inhibitor is amitriptyline, and the at least one KEEC is CLP 257, or The at least one monoamine reuptake inhibitor is amitriptyline, and the at least one KEEC is CLP 657, the combination according to claim 1.

11. The at least one monoamine reuptake inhibitor is paroxetine, and the at least one KEEC is PCZP. The at least one monoamine reuptake inhibitor is paroxetine, and the at least one KEEC is camazepam. The at least one monoamine reuptake inhibitor is duloxetine, and the at least one KEEC is PCZP. The at least one monoamine reuptake inhibitor is duloxetine, and the at least one KEEC is camazepam. wherein the at least one monoamine reuptake inhibitor is amitriptyline and the at least one KEEC is PCZP, or The combination according to claim 1, wherein the at least one monoamine reuptake inhibitor is amitriptyline and the at least one KEEC is camazepam.

12. A pharmaceutical composition comprising at least one monoamine reuptake inhibitor and at least one KEEC.

13. A kit of parts comprising the at least one monoamine reuptake inhibitor and the at least one KEEC as a combined preparation for simultaneous, separate, or sequential use.

14. The pharmaceutical composition according to claim 12, for medical use.

15. The pharmaceutical composition according to claim 12, for use in the treatment of pain sensation induced by peripheral neuropathy, by inflammation, or by diabetes.

16. The pharmaceutical composition according to claim 14 or 15, wherein the at least one monoamine reuptake inhibitor and the at least one KEEC are administered orally or intraperitoneally.

17. The kit of parts according to claim 13, for medical use.

18. The kit of parts according to claim 13, for use in the treatment of pain sensation induced by peripheral neuropathy, by inflammation, or by diabetes.

19. The kit of parts according to claim 17 or 18, wherein the at least one monoamine reuptake inhibitor and the at least one KEEC are administered orally or intraperitoneally.

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