Patent Description:
Lysosomal storage disorders (LSDs) are a group of inherited metabolic diseases caused by defects in lysosomal homeostasis. LSDs encompass over <NUM> diseases, with a collective clinical frequency of <NUM>:<NUM> live births. These diseases can be classified into two main groups: primary storage disorders resulting from a direct deficiency in degradation pathways (typically lysosomal enzyme deficiency disorders), and secondary storage disorders which are caused by malfunctioning downstream lysosomal proteins or processes that impact the lysosome (e.g., defects in trafficking pathways).

The pathology of LSDs affects many of the body's systems, but most commonly the nervous system. Progressive neurodegeneration resulting in physical disability and mental deterioration are common symptoms. Such disorders are generally severely progressive and unremitting. They tend to present in the first few years of life and the severe progression results in frequent hospitalization. If left untreated, patients often die in their mid-teens. Adult-onset patients have also been described.

Current therapeutic approaches to treat LSDs are limited. Miglustat is regarded as the first-line therapy for treating Niemann-Pick type C disease (NPC), <NPL>); <NPL>); <NPL>), but this drug causes unwanted weight loss and gastrointestinal disturbances in the treatment subjects. Acetyl-DL-leucine can also be used to treat NPC as a single agent, <NPL>), and has been administered as an add-on therapy in NPC subjects receiving miglustat as a first-line therapy. <NPL>); <NPL>); <CIT>. These add-on studies did not include NPC subjects naive to treatment with miglustat and were not designed to measure the combined therapeutic effects of acetyl-DL-leucine and miglustat. There is a need for improved treatments of LSDs with enhanced efficacy and an improved safety profile for first-line therapy.

The subject matter of the invention is as defined in the appended claims.

In all instances, disclosures relating to methods of treatment comprising administering acetyl-leucine and miglustat are to be understood as purpose-limited product claims, i.e. acetyl-leucine and miglustat for use in such methods of treatment.

Applicant has unexpectedly discovered that acetyl-leucine synergizes with miglustat to treat NPC, e.g., slow disease progression. Also, without wishing to be bound by any particular theory, it is believed that the combination of acetyl-leucine and miglustat will lessen the toxicity, e.g., weight loss and/or appetite suppression, typically associated with the administration of miglustat.

In one aspect, the present disclosure provides acetyl-leucine in combination with miglustat for use in the treatment of a LSD in a subject, wherein the subject is naive to treatment with miglustat.

In another aspect, the present disclosure provides a method of treating a LSD in a subject in need thereof, the method comprising administering a combination of (i) a therapeutically effective amount of acetyl-leucine; and (ii) a therapeutically effective amount of miglustat, to the subject, wherein the subject is naive to treatment with miglustat.

In another aspect, the present disclosure provides the combination of acetyl-leucine and miglustat for first-first line therapy to treat a LSD.

In another aspect, the present disclosure provides a kit comprising acetyl-leucine and miglustat for use in a method of treating a lysosomal storage disease in a subject, wherein subject is naive to treatment with miglustat.

It is to be understood that both the foregoing summary and the following detailed description are exemplary and explanatory only, and are not restrictive of the invention as claimed.

In one embodiment, the present disclosure provides acetyl-leucine in combination with miglustat for use in the treatment of a lysosomal storage disease (LSD) in a subject in need thereof, wherein the subject is naive to treatment with miglustat.

As used herein, the singular forms "a," "an," and "the" include plural reference.

As used herein, the terms "approximately" and "about" should be generally understood to encompass ± <NUM>% of a specified amount, frequency or value. Numerical quantities given herein are approximate unless stated otherwise, meaning that term "about" or "approximately" can be inferred when not expressly stated.

The terms "administer," "administration," or "administering" as used herein refer to (<NUM>) providing, giving, dosing and/or prescribing by either a health practitioner or his authorized agent or under his direction, the combination of acetyl-leucine and miglustat, and (<NUM>) putting into, taking or consuming by the subject or person himself or herself, acetyl-leucine and miglustat. Any reference to acetyl-leucine and miglustat include pharmaceutically acceptable salts of the same, even if not expressly stated.

A "pharmaceutically acceptable salt" as referred to herein, is any salt preparation that is appropriate for use in a pharmaceutical application. Pharmaceutically acceptable salts include, but are not limited to, amine salts, such as N,N'-dibenzylethylenediamine, chloroprocaine, choline, ammonia, diethanolamine and other hydroxyalkylamines, ethylenediamine, N-methylglucamine, procaine, N-benzylphenethylamine, <NUM>-para-chlorobenzyl-<NUM>-pyrrolidin-<NUM>'-ylmethylbenzimidazole, diethylamine and other alkylamines, piperazine, tris(hydroxymethyl)aminomethane and the like; alkali metal salts, such as lithium, potassium, sodium and the like; alkali earth metal salts, such as barium, calcium, magnesium and the like; transition metal salts, such as zinc, aluminum and the like; other metal salts, such as sodium hydrogen phosphate, disodium phosphate and the like; mineral acids, such as hydrochlorides, sulfates and the like; and salts of organic acids, such as acetates, lactates, malates, tartrates, citrates, ascorbates, succinates, butyrates, valerates, fumarates and the like.

Acetyl-leucine and miglustat may be formulated and administered to a subject in accordance with known teachings in the art. For example, acetyl-leucine and miglustat may be formulated as separate pharmaceutical compositions. These pharmaceutical compositions may comprise the active agent, i.e., acetyl-leucine or miglustat, and one or more pharmaceutically acceptable carriers. Acetyl-leucine and miglustat may also be formulated as single pharmaceutical composition comprising both active agents and one or more pharmaceutically acceptable carriers.

The pharmaceutical compositions comprising acetyl-leucine and miglustat, either separately or together in a single composition, may take any of a number of different forms depending on the manner in which they are to be used. Thus, for example, the pharmaceutical compositions may be in the form of a powder, tablet, capsule, liquid, ointment, cream, gel, hydrogel, aerosol, spray, micellar solution, transdermal patch, liposome suspension, or any other suitable form that may be administered to a subject in need of treatment.

A "pharmaceutically acceptable carrier" as referred to herein, is any known compound or combination of known compounds, e.g., excipients, carriers, etc., that are known to those skilled in the art to be useful in formulating pharmaceutical compositions. It will be appreciated that the carrier of the pharmaceutical composition should be one which is tolerated by the subject to whom it is given.

In one embodiment, the pharmaceutically acceptable carrier may be a solid, and the composition may be in the form of a powder or tablet. A solid pharmaceutically acceptable carrier may include, but is not limited to, one or more substances which may also act as flavouring agents, buffers, lubricants, stabilisers, solubilisers, suspending agents, wetting agents, emulsifiers, dyes, fillers, glidants, compression aids, inert binders, sweeteners, preservatives, dyes, coatings, or tablet-disintegrating agents. The carrier may also be an encapsulating material. In powders, the carrier may be a finely divided solid that is in admixture with the finely divided active agents according to the invention. In tablets, the active agent may be mixed with a carrier having the necessary compression properties in suitable proportions and compacted in the shape and size desired. The powders and tablets may, for example, contain up to <NUM>% of the active agents. Suitable solid carriers include, for example, calcium phosphate, magnesium stearate, talc, sugars, lactose, dextrin, starch, gelatin, cellulose, polyvinylpyrrolidine, low melting waxes and ion exchange resins. In another embodiment, the pharmaceutically acceptable carrier may be a gel and the composition may be in the form of a cream or the like.

The carrier may include, but is not limited to, one or more excipients or diluents. Examples of such excipients are gelatin, gum arabicum, lactose, microcrystalline cellulose, starch, sodium starch glycolate, calcium hydrogen phosphate, magnesium stearate, talcum, colloidal silicon dioxide, and the like.

In another embodiment, the pharmaceutically acceptable carrier may be a liquid. In one embodiment, the pharmaceutical composition is in the form of a solution. Liquid carriers are used in preparing solutions, suspensions, emulsions, syrups, elixirs and pressurized compositions. Acetyl-leucine and/or miglustat may be dissolved or suspended in a pharmaceutically acceptable liquid carrier such as water, an organic solvent, a mixture of both or pharmaceutically acceptable oils or fats. The liquid carrier may contain other suitable pharmaceutical additives such as solubilisers, emulsifiers, buffers, preservatives, sweeteners, flavouring agents, suspending agents, thickening agents, colours, viscosity regulators, stabilizers or osmo-regulators. Suitable examples of liquid carriers for oral and parenteral administration include water (partially containing additives as above, e.g. cellulose derivatives, such as sodium carboxymethyl cellulose solution), alcohols (including monohydric alcohols and polyhydric alcohols, e.g. glycols) and their derivatives, and oils (e.g. fractionated coconut oil and arachis oil). For parenteral administration, the carrier may also be an oily ester such as ethyl oleate and isopropyl myristate. Sterile liquid carriers are useful in sterile liquid form compositions for parenteral administration. The liquid carrier for pressurised compositions may be a halogenated hydrocarbon or other pharmaceutically acceptable propellant.

Liquid pharmaceutical compositions, which are sterile solutions or suspensions, may be utilised by, for example, intramuscular, intrathecal, epidural, intraperitoneal, intravenous and subcutaneous injection. The active agent may be prepared as a sterile solid composition that may be dissolved or suspended at the time of administration using sterile water, saline, or other appropriate sterile injectable medium.

The compositions may be administered orally in the form of a sterile solution or suspension containing other solutes or suspending agents (for example, enough saline or glucose to make the solution isotonic), bile salts, acacia, gelatin, sorbitan monoleate, polysorbate <NUM> (oleate esters of sorbitol and its anhydrides copolymerized with ethylene oxide) and the like. The compositions may also be administered orally either in liquid or solid composition form. Compositions suitable for oral administration include solid forms, such as pills, capsules, granules, tablets, and powders, and liquid forms, such as solutions, syrups, elixirs, and suspensions. Forms useful for parenteral administration include sterile solutions, emulsions, and suspensions.

In one embodiment, the pharmaceutical composition of both acetyl-leucine and miglustat is a solid oral dosage form, such as a tablet. In tablets, the active agent may be mixed with a vehicle, such as a pharmaceutically acceptable carrier, having the necessary compression properties in suitable proportions and compacted in the shape and size desired. The tablets may contain up to <NUM>% by weight of the active agents.

Pharmaceutical compositions in solid oral dosage form, such as tablets, may be prepared by any method known in the art of pharmacy. Pharmaceutical compositions are usually prepared by mixing the active agent with conventional pharmaceutically acceptable carriers.

A tablet may be formulated as is known in the art. Tanganil®, for example, includes wheat starch, pregelatinised maize (corn) starch, calcium carbonate and magnesium stearate as excipients. The same, or similar, excipients, for example, may be employed with the present disclosure.

The composition of each <NUM> Tanganil® tablet is as follows: <NUM> acetyl-DL-leucine, <NUM> wheat starch, <NUM> pregelatinised maize (corn) starch, <NUM> calcium carbonate and <NUM> magnesium stearate. The same tablets, for example, may be employed in the methods of the present disclosure.

As discussed above, acetyl-leucine and miglustat may be formulated and administered as a pharmaceutical composition taking any number of different forms. For example, acetyl-leucine may be formulated as a pharmaceutical composition to facilitate its delivery across the blood-brain barrier. As a further example, acetyl-leucine may be formulated as a pharmaceutical composition for bypassing the blood-brain barrier.

In one embodiment, the pharmaceutical composition, e.g., comprising acetyl-L-leucine, or salt thereof, is formulated for nanodelivery, e.g., colloidal drug-carrier systems. Suitable examples include but are not limited to liposomes, nanoparticles (e.g., polymeric, lipid and inorganic nanoparticles), nanogels, dendrimers, micelles, nanoemulsions, polymersomes, exosomes, and quantum dots. See, e.g., <NPL>); <NPL>); <NPL>); <NPL>).

In one embodiment, the pharmaceutical composition, e.g., comprising N-acetyl-L-leucine, or salt thereof, is formulated for direct delivery to the central nervous system (CNS), such as by injection or infusion. Formulations for and methods of direct delivery to the CNS are known in the art. See, e.g., <CIT>. Examples of such administration include but are not limited to intranasal, intraventricular, intrathecal, intracranial, and delivery via nasal mucosal grafting. In one embodiment, the pharmaceutical composition is administered by intracerebroventricular infusion.

In one embodiment, the pharmaceutical composition is formulated for (and administered by) intranasal delivery. See, e.g., <NPL>). In one embodiment, the pharmaceutical composition is formulated for (and administered by) delivery via a nasal mucosal graft. In one embodiment, the pharmaceutical composition is formulated for (and administered by) intracerebroventricular injection or infusion. In another embodiment, the pharmaceutical composition is formulated for (and administered by) intrathecal intracisternal injection or infusion. In one embodiment, the pharmaceutical composition is formulated for (and administered by) intrathecal lumbar injection or infusion.

Various techniques may be used including, without limitation, injection through a burrhole or cisternal or lumbar puncture or the like as known in the art. Various devices, whether internal (e.g., implanted) or external, may be used for delivery as known in the art, such as pumps, catheters, reservoirs, etc. In one embodiment, the administration interval is once every two weeks.

"Lysosomal storage disease" or "LSD" refers to any disorder that involves dysfunction or disruption in the late endosomal/lysosomal system and the accumulation of undigested or partially digested macromolecules. The LSD may involve increased storage of lipids or non-lipids. All LSDs are within the scope of the present disclosure.

In one embodiment, the LSD is chosen from any of glycogen storage disease, mucopolysaccaridoses, mucolipidoses, oligosaccharidoses, lipidoses, sphingolipidoses, and lysosomal transport diseases.

The glycogen storage disease may be chosen from Infantile-onset Pompe disease, Lateonset Pompe disease and Danon disease.

The mucopolysaccharidoses may be chosen from any of MPS IH, MPS I H-S, MPS IS, MPS IIA, MPS IIB, MPS IIIA-D, MPS IVA, MPS VI, MPS VII and MPS IX. In one embodiment, the mucopolysaccharidosis is MPS III or MPS VII. In one embodiment, the mucopolysaccharidosis is MPS IIIB.

The mucolipidoses may be chosen from any of mucolipidosis I, mucolipidosis II, mucolipidosis III, and mucolipidosis IV. In one embodiment the mucolipidosis is mucolipidosis II or mucolipidosis III.

The oligosaccharidoses may be chosen from any of beta-mannosidosis, alphafucosidosis, and aspartylglucosaminuria. In one embodiment, the oligosaccharidosis is aspartylglucosaminuria.

The lipidoses may be chosen from any of Niemann-Pick disease type C, Niemann-Pick disease type D, neuronal ceroid lipofuscinoses (Type I to X inclusive), and Wolman disease. In one embodiment, the lipidosis is Niemann-Pick disease type C.

The sphingolipidoses may be chosen from any of Niemann-Pick disease type A/B, Gaucher disease types I, II, and III, Krabbe disease, Fabry disease, Schindler Disease, GM1 gangliosidosis, Morquio B disease, GM2 gangliosidoses, metachromatic leukodystrophy, Farber disease, multiple sulfatase deficiency, lysosomal acid lipase deficiency and galactosialidosis. In one embodiment, the sphingolipidoses are chosen from Niemann-Pick disease type A, GM1 gangliosidosis, Tay-Sachs disease, the AB variant of Tay-Sachs disease, and Sandhoff disease.

The lysosomal transport diseases may be chosen from cystinosis, pycnodysostosis, sialic acid storage disease and infantile free sialic acid storage disease.

The LSD may be a primary lysosomal hydrolase defect, a post-translational processing defect of lysosomal enzymes, a trafficking defect for lysosomal enzymes, a defect in lysosomal enzyme protection, a defect in soluble non-enzymatic lysosomal proteins, a transmembrane (non-enzyme) protein defect or an unclassified defect.

In one embodiment, the LSD is chosen from a primary lysosomal hydrolase defect. Primary lysosomal hydrolase defects include, but are not limited to, Tay-Sachs disease (β-hexosaminidase A defect), Sandhoff disease (β-hexosaminidase A+B defect), Fabry disease (α-galactosidase A defect), Krabbe disease (β-galactosyl ceramidase defect), Niemann-Pick Type A and B (sphingomyelinase defect), metachromatic leukodystrophy (arylsulphatase A defect), MPS IH (Hurler syndrome; α-iduronidase defect), MPS IS (Scheie syndrome; α-iduronidase defect), MPS IH-S (Hurler-Scheie syndrome; α-iduronidase defect), MPS II (Hunter syndrome; iduronate sulphatase defect), MPS IIIA (Sanfilippo A syndrome; heparan sulphamidase defect), MPS IIIB (Sanfilippo B syndrome; acetyl α-glucosaminidase defect), MPS IIIC (Sanfilippo C syndrome; acetyl CoA: α-glucosaminide N-acetyltransferase defect), MPS IIID (Sanfilippo D syndrome; N-acetyl glucosamine-<NUM>-sulphatase defect), MPS IV A (Morquio A disease; acetyl galactosamine-<NUM>-sulphatase defect), MPS IVB (Morquio B disease; β-galactosidase defect), MPS V (redesignated MPS IS), MPS VI (Maroteaux Lamy Syndrome; acetyl galactosamine-<NUM>-sulphatase (arylsulphatase B) defect), MPS VII (Sly Syndrome; β-glucuronidase defect), MPS IX (hyaluronidase defect), Wolman/cholesteryl ester storage disease (WD; acid lipase defect), Pompe disease (Type II; α-<NUM>,<NUM>-glucosidase defect), aspartylglucosaminuria (glycosylasparaginase defect), fucosidosis (α-fucosidase defect), α-mannosidosis (α-mannosidase defect), β-mannosidosis <NUM> (β-mannosidase defect), Schindler disease (N-acetylgalactosaminidase defect), sialidosis/ML I (α-neuraminidase defect), infantile neuronal ceroid lipofuscinosis (CLN1; palmitoyl protein thioesterase defect), late infantile neuronal ceroid lipofuscinosis (CLN2; carboxypeptidase defect), early infantile GM1 gangliosidosis, late infantile GM1 gangliosidosis, adult infantile GM1 gangliosidosis, Gaucher Disease Type <NUM> (Non-Neuronopathic), Gaucher Disease Type <NUM>/<NUM> (Neuronopathic), Neuronal Ceroid Lipofuscinosis Type <NUM> (CLN4; Kufs disease; Adult NCL; palmotoyl-protein thioesterase-<NUM> deficiency (Type A); Cathepsin F deficiency (Type B)), Neuronal Ceroid Lipofuscinosis Type <NUM> (CLN10; Congenital Cathepsin D Deficiency), Pycnodysostosis (Cathepsin K defect), Infantile-Onset Pompe Disease, Late-Onset Pompe Disease, Farber Disease (Farber's lipogranulomatosis; ceramidase deficiency; Fibrocytic dysmucopolysaccharidosis; Lipogranulomatosis) and Galactosialidosis (protective protein cathepsin A defect, PPCA defect). In one embodiment, the primary lysosomal hydrolase defect is chosen from Tay-Sachs disease, Sandhoff disease, Niemann-Pick Type A, Niemann-Pick Type B, neuronal ceroid lipofuscinoses, Gaucher disease, Fabry disease, Krabbe disease, GM1 gangliosidosis, GM2 gangliosidosis, metachromatic leukodystrophy, and Farber disease. In one embodiment, the primary lysosomal hydrolase defect is chosen from Tay-Sachs disease, Sandhoff disease, Niemann-Pick Type A, Niemann-Pick Type B, and GM1 gangliosidosis.

In one embodiment, the LSD is Gaucher disease.

In one embodiment, the LSD is GM1 gangliosidosis.

The term "acetyl-leucine" refers collectively to N-acetyl-DL-leucine (ADLL), or a pharmaceutically acceptable salt thereof; N-acetyl-D-leucine (ADL), or a pharmaceutically acceptable salt thereof; and N-acetyl-L-leucine (ALL), or a pharmaceutically acceptable salt thereof. The term acetyl-leucine includes isotopically-labelled analogs of N-acetyl-DL-leucine, N-acetyl-D-leucine, and N-acetyl-L-leucine, wherein one or more atoms are replaced by an atom having a different atomic mass or mass number. Examples of isotopes that can be incorporated include isotopes of hydrogen, carbon, nitrogen, and oxygen, such as <NUM>H (or deuterium (D)), <NUM>H, <NUM>C, <NUM>C, <NUM>C, <NUM>N, <NUM>O, and <NUM>O. In one embodiment, provided is an isotopically-labelled analog of acetyl-leucine, wherein substantially all of the atoms at a position within acetyl-leucine are replaced by an atom having a different atomic mass or mass number. In another embodiment, provided is an isotopically-labelled analog of acetyl-leucine, wherein a portion of the atoms at a position within acetyl-leucine are replaced, e.g., acetyl-leucine is enriched at one or more positions with an atom having a different atomic mass or mass number. Isotopically-labelled acetyl-leucine can be prepared by methods known in the art.

In one embodiment, the N-acetyl-DL-leucine, N-acetyl-D-leucine, or N-acetyl-L-leucine is not isotopically-labelled.

In one embodiment, the isotopically-labelled analog is a deuterated analog of N-acetyl-DL-leucine, N-acetyl-D-leucine, or N-acetyl-L-leucine, wherein one or more hydrogen atoms are replaced with deuterium. In one embodiment, one hydrogen atom of N-acetyl-DL-leucine, N-acetyl-D-leucine, or N-acetyl-L-leucine is replaced with deuterium. In another embodiment, two hydrogen atoms of N-acetyl-DL-leucine, N-acetyl-D-leucine, or N-acetyl-L-leucine are replaced with deuterium. In another embodiment, three hydrogen atoms of N-acetyl-DL-leucine, N-acetyl-D-leucine, or N-acetyl-L-leucine are replaced with deuterium. In another embodiment, four hydrogen atoms of N-acetyl-DL-leucine, N-acetyl-D-leucine, or N-acetyl-L-leucine are replaced with deuterium. In another embodiment, five hydrogen atoms of N-acetyl-DL-leucine, N-acetyl-D-leucine, or N-acetyl-L-leucine are replaced with deuterium. In another embodiment, six hydrogen atoms of N-acetyl-DL-leucine, N-acetyl-D-leucine, or N-acetyl-L-leucine are replaced with deuterium.

In one embodiment, the acetyl-leucine used in the methods of the present disclosure is N-acetyl-DL-leucine, or a deuterated analog thereof. In another embodiment, the acetyl-leucine used in the methods of the present disclosure is N-acetyl-D-leucine, or a deuterated analog thereof. In another embodiment, the acetyl-leucine used in the methods of the present disclosure is N-acetyl-L-leucine, or a deuterated analog thereof.

In another embodiment, the acetyl-leucine used in the methods of the present disclosure is N-acetyl-DL-leucine. In another embodiment, the acetyl-leucine used in the methods of the present disclosure is N-acetyl-D-leucine. In another embodiment, the acetyl-leucine used in the methods of the present disclosure is N-acetyl-L-leucine.

"Miglustat" refers to <NUM>,<NUM>-(butylimino)-<NUM>,<NUM>-dideoxy-D-glucitol (also known as N-butyl-deoxynojirimycin).

"Administered in combination" and similar phrases mean that two agents, e.g., (<NUM>) acetyl-DL-leucine, acetyl-D-leucine, or acetyl-L-leucine; and (<NUM>) miglustat, are administered concurrently to the subject being treated. In one embodiment, acetyl-DL-leucine, acetyl-D-leucine, or acetyl-L-leucine and miglustat are administered in combination as a first line therapy to treat a LSD.

"First line therapy" means a treatment regimen generally accepted or recommended by the medical establishment or a regulatory authority, e.g., the U. Food and Drug Administration or the European Medicines Agency, for the initial treatment of a condition, disease, or disorder.

"Concurrently" means that each active agent is administered either (i) simultaneously; or (ii) sequentially in any order at different points in time. A combination of two agents is considered to be administered simultaneously if each agent is administered to the subject less than <NUM> minute apart. If not administered simultaneously, it is meant that both agents are administered to a subject in a sequence and sufficiently close in time so as to provide the desired therapeutic effect and can act in concert to treat a LSD.

In one embodiment, acetyl-leucine and miglustat are administered separately, in any appropriate form and by any suitable route. In one embodiment, both acetyl-leucine and miglustat are orally administered to the subject as tablets.

In one embodiment, acetyl-leucine is administered to the subject <NUM> minute to <NUM> hours before the administration of miglustat to the subject. For example, acetyl-leucine is administered <NUM> minutes, <NUM> minutes, <NUM> minutes, <NUM> minutes, <NUM> minutes, <NUM> hour, <NUM> hours, <NUM> hours, <NUM> hours, or <NUM> hours before the administration of miglustat to a subject.

In another embodiment, acetyl-leucine is administered simultaneously with miglustat to the subject.

In another embodiment, acetyl-leucine is administered to the subject <NUM> minute to <NUM> hours after the administration of miglustat to the subject. For example, acetyl-leucine is administered <NUM> minutes, <NUM> minutes, <NUM> minutes, <NUM> minutes, <NUM> minutes, <NUM> hour, <NUM> hours, <NUM> hours, <NUM> hours, or <NUM> hours after, the administration of miglustat to a subject.

In another embodiment, acetyl-leucine and miglustat are administered to the subject about <NUM> minute to about <NUM> hours apart. For example, acetyl-leucine and miglustat are administered about <NUM> minute apart, <NUM> minutes apart, <NUM> minutes apart, <NUM> minutes apart, <NUM> minutes apart, <NUM> hour apart, <NUM> hour to <NUM> hours apart, <NUM> hours to <NUM> hours apart, <NUM> hours to <NUM> hours apart, <NUM> hours to <NUM> hours apart, <NUM> hours to <NUM> hours apart, <NUM> hours to <NUM> hours apart, <NUM> hours to <NUM> hours apart, <NUM> hours to <NUM> hours apart, <NUM> hours to <NUM> hours apart, <NUM> hours to <NUM> hours apart, or <NUM> hours to <NUM> hours apart.

"Naive to treatment with miglustat" and similar phrases means that miglustat has not previously been administered to the subject to treat a LSD.

"Subject in need thereof" means a human who has a LSD and is need of treatment. The subject may or may not have been diagnosed a LSD. For example, the subject may not yet have a diagnosis (clinical or otherwise) of a LSD, but may have one or more symptoms of a LSD. The subject may also have a biochemical or other similar identifiable marker of a LSD.

A "therapeutically effective amount" of acetyl-leucine or miglustat is any amount of either active agent which, when administered to a subject, is the amount that is needed to produce the desired effect, which, for the present disclosure, can be therapeutic and/or prophylactic. The dose may be determined according to various parameters, such as the specific active agent used; the age, weight and condition of the patient to be treated; the route of administration; and the required regimen. A physician will be able to determine the required route of administration and dosage for any particular patient. For example, a daily dose of either active agent may be from about <NUM> to about <NUM> per kg, from about <NUM> to about <NUM> per kg, or from about <NUM> to about <NUM> per kg of body weight.

As used herein, "treating" or "treatment" refers to any indicia of success in preventing, arresting, or ameliorating a disease, disorder, condition, or syndrome, e.g., a LSD, in a subject, and/or preventing, arresting, or ameliorating any one or more symptoms a disease, disorder, condition, or syndrome, e.g., a LSD, in a subject, including any objective or subjective parameter such as abatement; remission; preventing, diminishing, inhibiting, or eliminating one or more symptoms; making the disease, disorder, condition, or syndrome more tolerable to the subject; slowing in the worsening of the disease, disorder, condition, or syndrome; or improving the physical or mental well-being of the subject in need thereof.

The terms "treating" or "treatment" also encompasses inducing inhibition, regression, or stasis of the disease, disorder, condition, or syndrome, e.g., a LSD. For example, treatment of a patient or subject in need of treatment for a LSD includes reducing a symptom of the LSD in the subject, inducing clinical response, inhibiting or reducing progression of the LSD, or inhibiting or reducing a complication of the LSD.

Preventing, arresting, or ameliorating an injury or pathology of a disease, disorder, condition, or syndrome, e.g., a LSD, e.g., NPC, such as preventing, diminishing, inhibiting, or eliminating one or more symptoms of disease, disorder, condition, or syndrome can be based on objective and/or subjective parameters, including, e.g., the results of physical examination(s), neurological examination(s), and/or psychiatric evaluation(s). The success of treatment for certain diseases e.g., a LSD, may be measured or evaluated by, for example, comparing the severity of the disease, e.g., objective and/or subjective parameters of the LSD, e.g., NPC, before treatment with acetyl-leucine and miglustat is initiated, with the severity of the disease following the initiation of treatment with acetyl-leucine and miglustat. For example, the severity of NPC may be assessed using a scale, index, rating, or score. In one embodiment, the treatment described herein improves such an assessment from a value or degree characteristic of a symptomatic subject to a value or degree characteristic of a non-symptomatic subject. In one embodiment, the treatment described herein improves such an assessment compared to a baseline. The baseline may be, for example, the subject's condition before initiating any treatment for the disease, e.g., NPC, or before initiating treatment for the disease with a acetyl-leucine and miglustat. Alternatively, the baseline may be, for example, the subject's condition after a certain time period on treatment for the disease. In one embodiment, treatment with acetyl-leucine and miglustat as described herein improves the subject's assessment (e.g., scale, index, rating, or score of objective and/or subjective parameters) compared to a baseline by at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>%, or at least <NUM>%. In one embodiment, assessment is improved by at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>%, or <NUM>%.

In one embodiment, acetyl-leucine is administered at a dose ranging from about <NUM> to about <NUM> per day. For example acetyl-leucine is administered at a dose ranging from about <NUM> to about <NUM> per day, a dose ranging from about <NUM> to about <NUM> per day, optionally by solid oral or liquid oral route. N-Acetyl-DL-leucine, may be administered, for example, in a dose according to that of Tanganil®, which is prescribed to adults in a dose of <NUM> to <NUM> per day, <NUM>-<NUM> tablets in two doses, morning and evening.

If a single enantiomer of acetyl-leucine, i.e., N-acetyl-D-leucine or N-acetyl-L-leucine, is administered the doses may be reduced accordingly. For instance, if only N-acetyl-L-leucine or if only N-acetyl-D-leucine is administered, the dose may range from about <NUM> to about <NUM> per day, range from about <NUM> to about <NUM> per day, or range from about <NUM> to about <NUM> per day, such as from about <NUM> to about <NUM> per day.

In one embodiment, the administered dose ranges of acetyl-leucine are from about <NUM> to about <NUM> per day. For example, the administered dose ranges of acetyl-leucine are from about <NUM> to about <NUM> per day, from about <NUM> to about <NUM> per day, or from about <NUM> to about <NUM> per day, from <NUM> to about <NUM> per day, <NUM> to about <NUM> per day, <NUM> to about <NUM> per day, <NUM> to about <NUM> per day, <NUM> to about <NUM> per day, or <NUM> to about <NUM> per day. It may be from about <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> to about <NUM> per day. It may be from about <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or <NUM> to about <NUM> per day. It may be from <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> to about <NUM> per day. It may be more than about <NUM> per day, but less than about <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or <NUM> per day. In one embodiment, the dose ranges from about <NUM> to about <NUM> per day. In one embodiment, the dose ranges from about <NUM> to about <NUM> per day. In one embodiment, the dose is about <NUM> per day. In one embodiment, the dose is about <NUM> per day. In one embodiment, the dose is about <NUM> per day, about <NUM> per day, about <NUM> per day, about <NUM> per day, about <NUM> per day, about <NUM> per day, about <NUM> per day, about <NUM> per day, about <NUM> per day, about <NUM> per day, about <NUM> per day, about <NUM> per day, about <NUM> per day, about <NUM> per day, or about <NUM> per day. In another embodiment, the dose is about <NUM> per day, about <NUM> per day, about <NUM> per day, about <NUM> per day, or about <NUM> per day. In another embodiment, the dose is about <NUM> per day, about <NUM> per day, about <NUM> per day, about <NUM> per day, about <NUM> per day, about <NUM> per day, about <NUM> per day, about <NUM> per day, about <NUM> per day, or about <NUM> per day. In one embodiment, these doses are administered in a solid oral dosage form, notably tablets. In another embodiment, these doses are for acetyl-leucine when in its racemic form. Doses for acetyl-leucine when an enantiomeric excess is present may be lower, for example, around <NUM>% lower. The above recited dose-ranges when halved are thus also explicitly encompassed by the present disclosure.

In one embodiment, miglustat is administered at a dose ranging from about <NUM> to about <NUM> per day. In another embodiment, miglustat is administered at a dose of about <NUM> per day. In another embodiment, miglustat is administered at a dose of about <NUM> per day. In another embodiment, miglustat is administered at a dose of about <NUM> per day. In another embodiment, miglustat is administered at a dose of about <NUM> per day. In another embodiment, miglustat is administered at a dose of about <NUM> per day. In another embodiment, miglustat is administered at a dose of about <NUM> per day. In another embodiment, miglustat is administered at a dose of about <NUM> per day. In another embodiment, miglustat is administered at a dose of about <NUM> per day. In another embodiment, miglustat is administered at a dose of about <NUM> per day. In another embodiment, miglustat is administered at a dose of about <NUM> per day.

In one embodiment, the total daily dose of acetyl-leucine may be spread across multiple administrations, i.e., administration may occur two or more times a day to achieve the total daily dose. As an example, the required number of tablets to provide the total daily dose of a acetyl-leucine may be split across two administrations (for example, in the morning and evening) or three administrations (for example, in the morning, noon and evening). Each dose may be suitably administered with or without food. For example, N-acetyl-L-leucine or N-acetyl-DL-leucine may be dosed by about <NUM> or about <NUM> hours before meals, such as at least about <NUM> minutes, at least about <NUM> minutes, at least about <NUM> minutes, or at least about <NUM> hour before meals, or may be dosed by about <NUM>, about <NUM>, or about <NUM> hours after meals, such as waiting at least about <NUM> minutes, at least about <NUM> minutes, at least about <NUM> hour, at least about <NUM> hours, at least about <NUM> hours, or at least about <NUM> hours after meals. For example, a total daily dose of <NUM> acetyl-DL-leucine may be administered as three Tanganil® (or equivalent) tablets before, with, or after breakfast, three further tablets before, with, or after lunch and three further tablets before, with, or after dinner.

The treatment duration for the combination of acetyl-leucine and miglustat may be about seven days or more. For example, the treatment duration may be about two weeks or more, about three weeks or more, about one month or more, about six weeks or more, about seven weeks or more, or about two months or more. In one embodiment, the treatment duration is about three months or more, e.g., about four months or more, about five months or more or about six months or more. The treatment duration may also be about <NUM> year or more, about <NUM> years or more, about <NUM> years or more, about <NUM> years or more, or about <NUM> years or more. The treatment duration may also be the life-time of the subject.

Any and all combinations of dosage form, dose amount, dosing schedule, and treatment duration for the combination of acetyl-leucine and miglustat are envisaged and encompassed by the disclosure. In one embodiment, the dose of acetyl-leucine is from about <NUM> to about <NUM> per day, taken across one, two, or three administrations per day, for a treatment duration of about two months or more. In another embodiment, the dose of acetyl-leucine is more than <NUM> but no more than <NUM> per day, taken across one, two, or three administrations per day, for a treatment duration of about six months or more. The dosage form may be a solid oral dosage form, notably tablets.

In one embodiment, the combination of acetyl-leucine and miglustat is used for treating a LSD or one or more symptoms of a LSD. As used herein, "treating a LSD or one or more symptoms of a LSD" and the like refer to delaying onset of a LSD or one or more symptoms of a LSD that would otherwise be expected to manifest according to typical disease progression, reducing the severity of a LSD or reducing the severity of or eliminating one or more existing symptoms associated with a LSD, delaying progression of a LSD or one or more symptoms of a LSD over time as compared to typical disease progression, and/or reversing progression of a LSD or one or more symptoms of a LSD over time. "Treating a LSD or one or more symptoms of a LSD" may also refer to improving a biochemical marker of a LSD.

As used herein, "typical disease progression," "disease progression that would typically be expected" and the like refer to the typical or expected progression of a LSD, one or more symptoms associated with a LSD, or a biochemical marker of a LSD if the subject were untreated. Typical or expected disease progression may be based, for example, on a known scale, index, rating, or score, or other suitable test, for assessing the progression of a LSD, one or more symptoms associated with a LSD, or a biochemical marker of a LSD, such as those described herein. The scale, index, rating, score, or other suitable test may correspond to the progression of the LSD overall or to the progression of one or more symptoms associated with the LSD. For instance, typical or expected disease progression may be based on the typical or expected onset or severity of the LSD or a symptom or collection of symptoms associated with the LSD. The typical or expected disease progression may be determined on a subject-by-subject basis or may be based on what is typically observed for or experienced by a collection of subjects afflicted with the LSD, such as a population or subpopulation of subjects. Subpopulations may include, for example, subpopulations of the same gender, of the same or similar age, of the same or similar timing for the onset of one or more symptoms, etc..

In another embodiment, "treating a LSD or one or more symptoms of a LSD" refers to delaying onset of a LSD or one or more symptoms of a LSD that would otherwise be expected to manifest according to typical disease progression. As used herein, "delaying onset of a LSD or one or more symptoms of a LSD" and the like refer to increasing the time to, or preventing, onset of the LSD or one or more symptoms of the LSD. For example, onset can be said to be delayed when the time to manifestation of a LSD or one or more symptoms of a LSD takes at least <NUM>% longer than that observed according to typical disease progression. Further for example, an increase in time of at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>% or at least <NUM>% is observed. In one embodiment, the subject is asymptomatic. The administration of acetyl-leucine and miglustat may be initiated at the time the subject is asymptomatic to delay onset of a LSD or one or more symptoms of a LSD that would otherwise be expected to manifest according to typical disease progression. In another embodiment, the subject is symptomatic. The administration of acetyl-leucine and miglustat may be initiated at the time the subject has some symptoms in order to delay onset of one or more additional symptoms of a LSD that would otherwise be expected to manifest according to typical disease progression. The subject in need thereof may continue to receive treatment with acetyl-leucine and miglustat in accordance with the durations described herein. In one embodiment, the treatment prevents onset of one or more symptoms of the LSD that would otherwise be expected to manifest according to typical disease progression.

In another embodiment, "treating a LSD or one or more symptoms of a LSD" refers to reducing the severity of a LSD or reducing the severity of or eliminating one or more existing symptoms associated with a LSD. The severity of a LSD or of the existing symptom(s) may be assessed using a known scale, index, rating, or score, such as those described as examples herein, or another suitable test for assessing severity. For example, the scale, index, rating, score, or other suitable test may correspond to the severity of the LSD overall or to the severity of one or more symptoms associated with the LSD. In one embodiment, the treatment improves such an assessment from a value or degree characteristic of a symptomatic patient to a value or degree characteristic of a non-symptomatic patient.

In another embodiment, "treating a LSD or one or more symptoms of a LSD" refers to delaying progression of a LSD or one or more symptoms associated with a LSD over time as compared to typical disease progression, or reversing progression of a LSD or one or more symptoms associated with a LSD over time. The time over which the treatment delays or reverses progression may coincide with the duration of treatment as described herein. The treatment may delay or reverse progression over a duration of, for example, about seven days or more, about two weeks or more, about three weeks or more, about one month or more, about six weeks or more, about seven weeks or more or about two months or more. For example, the treatment delays or reverses progression over a duration of about three months or more, about four months or more, about five months or more or about six months or more. Further for example, it delays or reverses progression over a duration of about <NUM> year or more, about <NUM> years or more, about <NUM> years or more, about <NUM> years or more, about <NUM> years or more, or about <NUM> years or more. The treatment may delay or reverse progression of the LSD or one or more symptoms associated with the LSD over the lifetime of the patient.

In another embodiment, "treating a LSD or one or more symptoms of a LSD" refers to delaying progression of a LSD or one or more symptoms of a LSD over time as compared to typical disease progression. As used herein, "delaying progression of a LSD or one or more symptoms associated with a LSD over time" and the like refer to slowing and/or stopping progression of the LSD or one or more symptoms of the LSD (e.g., slowing and/or stopping the worsening or increasing severity of the LSD or one or more symptoms of the LSD) over time. Disease progression may be determined, for example, using a known scale, index, rating, or score, such as those described as examples herein, or other suitable tests for assessing progression. For example, the scale, index, rating, score, or other suitable test may correspond to the progression of the LSD overall or to the progression of one or more symptoms associated with the LSD. In one embodiment, "delaying progression of a LSD or one or more symptoms associated with a LSD" means that a subject's disease severity value (e.g., overall severity or severity of one or more symptoms) determined by a known scale, index, rating, score, etc., or another suitable test for evaluating severity, does not meaningfully increase (e.g., at least remains substantially constant). In one embodiment, "delaying progression of a LSD or one or more symptoms of a LSD" means preventing the subject from reaching, or increasing the time taken for a subject to reach (e.g., decreasing the rate of change of increasing severity), a severity value according to a known scale, index, rating, score, etc., or other suitable test, for assessing progression compared to a value corresponding to typical disease progression. For example, progression can be said to be delayed when the time to reach a severity value takes at least <NUM>% longer than that observed according to typical disease progression. Further for example, an increase in time of at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>%, at least <NUM>% or at least <NUM>% is observed. The time over which the treatment delays progression of a LSD or one or more symptoms of a LSD may coincide with the duration of treatment as described herein. In one embodiment, the treatment delays progression for at least about three months, at least about four months, at least about five months, or at least about six months. In another embodiment, the treatment delays progression for at least about <NUM> year, at least about <NUM> years, at least about <NUM> years, at least about <NUM> years, at least about <NUM> years, or at least about <NUM> years. The treatment may delay progression over the lifetime of the patient.

In another embodiment, "treating a LSD or one or more symptoms of a LSD" refers to reversing progression of a LSD or one or more symptoms of a LSD over time. As used herein, "reversing progression of a LSD or one or more symptoms of a LSD over time" and the like refer to stopping progression and reducing the severity of the LSD or one or more symptoms of the LSD over time. Disease progression and severity may be determined, for example, using a known scale, index, rating, or score, such as those described as examples herein, or another suitable test for assessing progression and severity. For example, the scale, index, rating, score, or other suitable test may correspond to the progression and severity of the LSD overall or to the progression and severity of one or more symptoms associated with the LSD. In one embodiment, "reversing progression of a LSD or one or more symptoms of a LSD over time" means that a subject's disease severity value (e.g., overall severity or severity of one or more symptoms) determined by a known scale, index, rating, score, etc., or another suitable test, for evaluating severity, improves over time (i.e., shows a reduction in severity over time). The time over which the treatment reverses progression of a LSD or one or more symptoms of a LSD may coincide with the duration of treatment as described herein. In one embodiment, the treatment reverses progression for at least about three months, at least about four months, at least about five months, or at least about six months. In another embodiment, the treatment reverses progression for at least about <NUM> year, at least about <NUM> years, at least about <NUM> years, at least about <NUM> years, at least about <NUM> years, or at least about <NUM> years. The treatment may reverse progression over the lifetime of the patient.

In another embodiment, "treating a LSD or one or more symptoms of a LSD" refers to improving in the subject a biochemical marker of a LSD (e.g., increased levels of the storage metabolite(s) or secondary biochemical changes resulting from the primary storage). A biochemical marker is a signal of disease activity and may provide ongoing indications of disease severity and progression over time. In one embodiment, the biochemical marker is improved in view of a control value. In one embodiment, the biochemical marker is chosen from increased lysosomal volume and increased glycosphingolipid (GSL) levels. In one embodiment, the biochemical marker is increased lysosomal volume and the treatment reduces lysosomal volume in the subject. In one embodiment, the biochemical marker is increased glycosphingolipid (GSL) levels and the treatment reduces GSL levels in the subject. In one embodiment, the treatment improves a biochemical marker over time. For example, in one embodiment, improving a biochemical marker over time means that the treatment improves a biochemical marker over time toward a control value, prevents the progression of a biochemical marker over time, and/or delays the progression of the biochemical marker over time as compared to typical disease progression. The time over which the treatment improves a biochemical marker may coincide with the duration of treatment as described herein. In one embodiment, the treatment improves a biochemical marker for at least about three months, at least about four months, at least about five months, or at least about six months. In a further embodiment, the treatment improves a biochemical marker for at least about <NUM> year, at least about <NUM> years, at least about <NUM> years, at least about <NUM> years, at least about <NUM> years, or at least about <NUM> years. The treatment may improve the biochemical marker over the lifetime of the patient.

A "symptom" of a LSD includes any clinical or laboratory manifestation associated with a LSD and is not limited to what the subject can feel or observe. Symptoms as described herein include, but are not limited to, neurological symptoms and psychiatric symptoms. Examples of neurological symptoms include ataxia, other movement disorders such as hypokinesia, rigor, tremor or dystonia, central ocular motor disorders such as vertical and horizontal supranuclear saccade/gaze palsy and neuropsychological deficits such as dementia. Examples of psychiatric symptoms include depression, behavioural disorders or psychosis. Onset of symptoms may range from birth to adulthood.

Progression of a LSD or one or more symptoms of a LSD over time or through treatment can be monitored, for example, using one or more known tests at two or more time points and comparing the results. Disease progression and/or severity can be assessed, for example, using the Scale for the Assessment and Rating of Ataxia (SARA), Spinocerebellar Ataxia Functional Index (SCAFI), the International Cooperative Ataxia Rating Scale (ICARS), the brief ataxia rating scale (BARS), the modified Disability Rating Scale (mDRS), EuroQol 5Q-5D-<NUM> (EQ-5D-<NUM>), the visual analogue scale (VAS), Wechsler Adult Intelligence Scale-Revised (WAIS-R), Wechsler Intelligence Scale for Children-IV (WISC-IV), Montreal Cognitive Assessment (MoCA) or other suitable tests. For certain LSDs, such as NPC, particular scores have been developed and validated over the last decades, for instance the clinical severity score (CSS) and annual severity increment score (ASIS) (see Yanjanin et al. , "Linear Clinical Progression, Independent of Age of Onset, in Niemann-Pick Disease, Type C," Am J Med Genet Part B 153B:<NUM>-<NUM>) and the modified <NUM>-Domain NP-C disability Scale (mDRS score). For example, an NPC patient's severity can be quantified by assigning a CSS, which assesses various parameters of the disease (ambulation, seizures, eye movement, etc.) and gives each parameter a score out of <NUM>. A higher score equals a greater severity. The ASIS quantifies the annual rate of change in the CSS, calculated by dividing the CSS by the patient's age. In this regard, certain scores in these tests are characteristic of symptomatic LSD patients and evidence disease progression and/or severity.

Thus, "treating a LSD or one or more symptoms of a LSD," for example, may be equated to achieving an improved assessment, such as those described herein, of a SARA, SCAFI, ICARS, BARS, mDRS, EQ-5D-<NUM>, VAS, WAIS-R, WISC-IV, CSS and/or MoCA score, or result of another test suitable for characterising a LSD subject. For example, in one embodiment, "reducing the severity of a LSD or reducing the severity of or eliminating one or more existing symptoms of a LSD" means improving a SARA, SCAFI, ICARS, BARS, mDRS, EQ-5D-<NUM>, VAS, WAIS-R, WISC-IV, CSS and/or MoCA score, or a result of another suitable test for evaluating severity, such as improving the score or result from a severity value characteristic of a symptomatic subject to a value characteristic of a non-symptomatic subject. In another embodiment, "delaying progression of a LSD or one or more symptoms of a LSD" means that a subject's SARA, SCAFI, ICARS, BARS, mDRS, EQ-5D-<NUM>, VAS, WAIS-R, WISC-IV, CSS and/or MoCA score, or a result of another suitable test for evaluating progression, does not meaningfully increase (e.g., at least remains substantially constant). In a further embodiment, "delaying progression of a LSD or one or more symptoms of a LSD" means preventing a subject's SARA, SCAFI, ICARS, BARS, mDRS, EQ-5D-<NUM>, VAS, WAIS-R, WISC-IV, CSS and/or MoCA score, or a result of another suitable test for evaluating progression, from reaching, or increasing the time taken to reach, a value compared to that of typical disease progression. In another embodiment, "reversing progression of a LSD or one or more symptoms of a LSD over time" means that a subject's SARA, SCAFI, ICARS, BARS, mDRS, EQ-5D-<NUM>, VAS, WAIS-R, WISC-IV, CSS and/or MoCA score, or result of another suitable test for evaluating progression, improves over time (i.e., shows a reduction in severity over time).

For example, to evaluate overall neurological status, mDRS, a four-domain scale (ambulation, manipulation, language and swallowing), may be applied. Cerebellar function may be evaluated using SARA, an eight-item clinical rating scale (gait, stance, sitting, speech, fine motor function and taxis; range <NUM>-<NUM>, where <NUM> is the best neurological status and <NUM> the worst), and SCAFI, comprising the <NUM>-m-Walking-Time (8MW; performed by having patients walking twice as quickly as possible from one line to another excluding turning), <NUM>-Hole-Peg-Test (9HPT) and the number of "PATA" repetitions over <NUM>. Subjective impairment and quality of life may be evaluated using the EQ-5D-<NUM> questionnaire and VAS. To assess ocular motor function, <NUM>-dimensional videooculography (EyeSeeCam) may be used to measure the peak velocity of saccades, gain of smooth pursuit, peak slow phase velocity of gaze-evoked nystagmus (gaze-holding function), peak slow phase velocity of optokinetic nystagmus, and gain of horizontal vestibulo-ocular reflex. To evaluate the cognitive state, WAIS-R or WISC-IV, and MoCA, assessing different cognitive domains, including attention and concentration, executive functions, memory, language, visuoconstructional skills, conceptual thinking, calculations, and orientation with a maximum of <NUM> points and a cut-off score of <NUM>, may be used. The skilled person will know how to perform these and other such tests.

BALBc/NPCnih and Sandhoff mice were bred as heterozygotes to generate affected mice (Npc1-/- Hexb-/-) and controls (Npc1+/+ Hexb+/+). The mice were housed under non-sterile conditions, with food and water available ad libitum. All experiments were conducted using protocols approved by the UK Home Office Animal Scientific Procedures Act, <NUM>.

Wild type and NPC1 null Chinese Hamster Ovary (CHO) cells were kindly provided by Chris Wassif (NIH).

The antibodies used in this study are summarised in Table <NUM>.

ADLL and enantiomers (ADLL: Molekula #<NUM>, ALL: Sigma Aldrich #<NUM>, ADL: Sigma #A0876) were administered as dry admix in powdered mouse diet (PicoLab Rodent Diet <NUM>/<NUM>, LabDiet) at a dose of <NUM>/kg/day for in vivo studies. Treatment groups for in vivo study consisted of at least <NUM> mice per group. In vitro studies were conducted with each compound dissolved in PBS to generate a <NUM> stock solution and diluted to a <NUM> working concentration in media (DMEM High Glucose-Gibco #<NUM>).

Miglustat (Monsanto/Oxford GlycoSciences) was administered as a dry solid mixed with powdered chow (<NUM>/kg/day) (see above) alone or in combination with ADLL.

The weight and activity of each mouse was recorded weekly until reaching the humane endpoint (defined as a loss of <NUM> body weight within <NUM>). Gait analysis was performed using CatWalk <NUM> system (Noldus) according to the manufacturer's instructions and five runs were recorded per animal at each time point. The camera was set to <NUM> below the walkway, the walkway was approximately <NUM> wide, and detection settings set to camera gain <NUM> and green intensity <NUM>. Motor function was measured using an accelerating NG Rota Rod for mice (Ugo Basile) starting from <NUM> rpm to <NUM> rpm, accelerating every <NUM> seconds by one rpm. Bar crossing experiments on Sandhoff animals were conducted to measure motor strength and coordination. The apparatus used was modified from published studies. Briefly, a metal bar (<NUM> width and <NUM> in length) was suspended horizontally between two wooden supports <NUM> high over a cushioned surface and animals were allowed to grasp the center of the bar with forepaws only, the tail was released, and the clock was started. Latency to cross or fall from the bar was scored, with <NUM> sec, maximum, to termination of each trial. A score was given to each animal between +<NUM> and -<NUM>. If crossing time was greater than <NUM>, then score = <NUM>- CT; if falling time was greater than <NUM>, the score = FT-<NUM>.

Biochemical and immunohistochemical analyses. Mice were saline perfused under terminal anaesthesia. Tissues for biochemical analysis were snap-frozen on ice-cold isopentane. For immunofluorescent staining, tissues were perfused with <NUM>% PFA followed by PBS and kept in <NUM>% PFA for <NUM> and stored in PBS containing <NUM>% sucrose longer term. Brains were cut parasagitally (<NUM> micron sections) and stored in <NUM>% ethylene glycol, <NUM>% glycerol <NUM> sodium phosphate buffer (pH <NUM>) at -<NUM>. Biochemical analysis was performed on water-homogenised tissues (<NUM>/ml) and protein content was determined using a BCA protein assay (Thermo Fisher #<NUM>) according to the manufacturer's instructions.

Western blot analyses. Western blot analysis was carried out by homogenising half cerebellums (ranging from <NUM> to <NUM> wet weight) in RIPA buffer (Pierce RIPA Buffer, Thermo Fischer Scientific-<NUM>) with protease/phosphatase inhibitor cocktail (Halt™ Protease and Phosphatase Inhibitor Cocktail-100X, Cat No: <NUM>) to achieve <NUM>/ml w/v. Samples then incubated for <NUM> minutes on ice. They were centrifuged at <NUM>,<NUM> at <NUM> and supernatants were retained for BCA protein assay and western blotting.

ADP and ATP extraction. ADP and ATP were extracted with Phenol-TE from tissues according to published methods. Briefly, freshly prepared tissues were homogenized with <NUM> of ice-cold phenol-TE (Sigma-<NUM>) and processed with three cycles of <NUM>-s homogenization and <NUM>-s cooling. One mL of homogenate was transferred into tubes containing <NUM> uL of chloroform and <NUM> uL of de-ionized water. The homogenate was thoroughly shaken for <NUM> and centrifuged at <NUM>,<NUM> × g for <NUM> at <NUM> (standardise all temps to this format). The supernatant was diluted <NUM>-fold with deionized water, the diluted extract was used for ADP/ATP analyses.

NAD and NADH extraction. NAD and NADH extractions were performed with <NUM> fresh tissue that was PBS washed on wet ice. Tissues were homogenised with a Dounce homogeniser with <NUM> uL of NADH/NAD extraction buffer (Abcam NAD/NADH Assay kit-ab65348), followed by centrifugation for <NUM> at <NUM> at <NUM>. Supernatants were collected into a new tube and filtered through 10kD Spin column (Abcam, #ab93349) at <NUM>,<NUM> at <NUM> until the majority of the liquid had passed through (approximately <NUM>).

Sphingoid Base Measurements: Sphingoid bases (sphingosine and sphinganine) were extracted from <NUM> uL tissue homogenates in <NUM> uL of chloroform: methanol (<NUM>:2v/v) followed by sonication for <NUM> minutes at room temperature. Subsequently, <NUM> <NUM>-uL sodium chloride, <NUM> uL chloroform, and <NUM> <NUM> uL sodium hydroxide were added to the samples, and vortexed every five minutes for <NUM> minutes at room temperature. Homogenates were centrifuged (<NUM>,<NUM> for <NUM> minutes) and the lower organic phase retained. Sphingoid bases were purified from the samples by pre-equilibrating SPA-NH2 columns with <NUM> x <NUM> chloroform followed by sample elution with 3x300 ul acetone. The samples were dried under nitrogen. Lipids were resuspended in <NUM> uL pre-warmed ethanol (<NUM>) and <NUM> uL OPA labelling solution (<NUM> OPA/<NUM> uL Ethanol/<NUM> uL <NUM>-mercaptoethanol; dilution <NUM>:<NUM> in <NUM>% boric acid pH <NUM>) was added. Samples were kept at room temperature in the dark for <NUM> minutes and vortexed every <NUM> minutes. Samples were buffered with <NUM> uL methanol: <NUM> Tris pH <NUM> (<NUM>:<NUM>) and centrifuged at <NUM>,<NUM> for <NUM> minutes. Supernatants (<NUM> uL) were loaded onto a reverse phase HPLC. Chromatography was carried out using a mobile phase of <NUM>% acetonitrile/<NUM>% H<NUM>O at a flow rate of <NUM>/min. The orthophthaldehyde-labelled derivatives were monitored at an excitation wavelength of <NUM> and an emission wavelength of <NUM>. Quantification of trace peak area was carried out using EZChrom Elite software v3.

Glycosphingolipid measurements: Glycosphingolipids were extracted and measured by NP-HPLC according to published methods. Tissue homogenates in chloroform/methanol (C:M) (<NUM>:<NUM> v/v) overnight at <NUM>. The mixture was centrifuged (<NUM> rpm/<NUM>) and <NUM> chloroform and <NUM> PBS were added to the supernatant and centrifuged (<NUM> rpm/<NUM>). The lower phase was dried under N<NUM>, resuspended in <NUM> uL C:M <NUM>:<NUM> v/v and combined with the upper phase. Subsequently, GSLs were recovered using C18 Isolute columns (<NUM>) (Biotage) pre-equilibrated with 4x1 mL MeOH and 2x1 mL H<NUM>O. Samples were washed 3x1 mL H<NUM>O and eluted with <NUM> C:M <NUM>:<NUM>, 2x1 mL C:M <NUM>:<NUM>, <NUM> MeOH. The column eluate was dried under N<NUM>, resuspended in <NUM> uL C:M <NUM>:<NUM>, dried again under N2 and resuspended in ceramide glycanase (CGase) buffer (<NUM> sodium acetate pH <NUM>, <NUM>/mL sodium taurodeoxycholate). <NUM> mU CGase was added, and samples incubated at <NUM> overnight. Released oligosaccharides were anthranilic acid (<NUM>-AA) labelled and purified by mixing with <NUM> Acetonitrile: H<NUM>O <NUM>:<NUM> and added to Discovery DPA-<NUM> columns (SUPELCO, # <NUM>-U) pre-equilibrated with <NUM> acetonitrile, 2x1 mL H<NUM>O, and 2x1 mL acetonitrile. Columns were washed with 2x1 mL Acetonitrile: H<NUM>O <NUM>:<NUM> v/v, and eluted in 2x <NUM> H<NUM>O. Samples were loaded <NUM>:<NUM><NUM>O: MeCN (v/v) for normal phase HPLC. Solvent A was acetonitrile, solvent B was H<NUM><NUM>, and solvent C was <NUM> NH<NUM>OH (pH <NUM>) in H<NUM><NUM>. Separation was carried out at <NUM> using Waters Alliance <NUM> separation module, excitation <NUM>, emission <NUM> using Waters <NUM> Fluorescence detector.

Cholesterol measurements: Cholesterol was measured with the Amplex Red kit (Molecular Probes) according to the manufacturer's instructions. Briefly, cell and tissue homogenates in <NUM> uL mQ water were Folch extracted and dried down under nitrogen. The pellets containing cholesterol were resuspended in 1X Reaction Buffer, and <NUM> uL was loaded for each sample in a flat bottom <NUM>-well plate. The reaction was initiated by adding Working Solution per sample (<NUM>% Amplex® Red, 2U/mL HRP stock solution, <NUM> U/mL cholesterol oxidase stock solution, <NUM> U/mL cholesterol esterase stock solution in 1X Reaction Buffer). Samples were incubated at <NUM> for <NUM> minutes and the fluorescence was measured in a microplate reader (Optima, BMG Labtech) using excitation in the range of <NUM>-<NUM> and emission detection at ~<NUM>.

Lysotracker Green and Propidium Iodide Staining of CHO cells: In vitro FACS experiments were performed in order to measure relative acidic compartment volume staining live cells with LysoTracker™ Green DND-<NUM> (Thermo Fisher-L7526) at <NUM> for <NUM> minutes in PBS at RT, centrifuged at 1200rpm for <NUM> and cells resuspended in FACS buffer (PBS, <NUM>% BSA, <NUM>% NaN3 sodium azide). Cells were stained with propidium iodide (<NUM>) (Invitrogen-P3566) immediately prior to analysis on the FACS for dead cell discrimination. FACS analysis was performed on <NUM>,<NUM> recorded cells using FACS Canto (Becton Dickinson, (BD)) with BD software.

Filipin Staining: Free cellular cholesterol in CHO cells was visualized with Filipin (from Streptomyces filipinensis (Sigma)). Cells were fixed with <NUM>% paraformaldehyde, washed <NUM> x PBS and incubated with <NUM>/mL glycine for <NUM> to quench auto-fluorescence. Cells were incubated with filipin (<NUM>/mL in PBS/<NUM>% FBS/<NUM>% Triton x100) for <NUM> hours, washed 3xPBS and visualized by Leica-SP8 confocal microscope.

Immunohistochemistry: Free-floating brain sections in glycerol/ethylene were rinsed <NUM> times with PBS and blocked with <NUM>% goat serum in <NUM>% PBS Triton at room temperature. Sections were stained with primary antibodies; rabbit Calbindin (<NUM>:<NUM>) and rat CD68 (<NUM>:<NUM>) in <NUM>% goat serum in <NUM>% PBS for <NUM> hours at <NUM>, followed by washing with <NUM>% PBS Triton, then <NUM> times with PBS. Secondary antibody staining (Alexa Fluor <NUM> Goat anti rabbit Far Red, Alexa Fluor <NUM> Goat anti rat) was conducted at room temperature for <NUM> hours. The antibodies used are summarised in Table <NUM>. Samples were washed once with <NUM>% PBS Triton, <NUM> times with PBS and manually mounted on slides. Slides left on the bench overnight to dry the sections followed by application of ProLong Gold (Invitrogen, #P36930).

Western Blotting: Homogenates of cerebellum (<NUM>/ml) were stored with <NUM>% Igepal CA, <NUM>% sodium deoxycholate, <NUM>% SDS, and <NUM>% protease-phosphatase inhibitor cocktail. Samples were resolved using <NUM>-<NUM>% SDS Tris-Glycine (Biorad) gel electrophoresis and transferred to low fluorescent PVDF membrane (Biorad Immunblot Low Fluorescence PVDF paper-#<NUM>) using a semidry transfer apparatus (Trans-Blot Turbo Transfer System (Biorad #<NUM>)). The antibodies used are summarised in Table <NUM>.

Image Acquisition and Quantification: Brain sections and CHO cells imaging was performed with a Leica-SP8 confocal microscope in tile imaging mode. Western blot data acquisition was conducted with LiCOR Odyssey Infrared Imaging system model no <NUM>. Mean fluorescence values, cerebellum diameters and areas, cell quantifications were calculated with Fuji Version <NUM> software.

ADP/ATP measurements: ADP/ATP measurements were made using a kit (Sigma Aldrich, MAK135) according to the manufacturer's instructions. The ADP/ATP ratio was calculated with the equation: (RLU-C-RLUB)/RLU-A.

NAD and NADH measurements: NAD, NADH and total NAD (NADt) (NAD+NADH = NADt) were measured with the NAD/NADH assay kit (Abcam-ab65348). Fresh samples were processed for ADP ATP extraction. Each sample was divided into <NUM>: <NUM>) Normal samples <NUM>) Decomposed samples. Decomposition of each sample was achieved by heating samples at <NUM> for <NUM> minutes on a heating block. <NUM> uL extracts were loaded into flat bottom clear <NUM> well plates, each sample comprising <NUM> wells: <NUM>) Background <NUM>) NADt <NUM>) Decomposed samples (contains only NADH). Background reaction mix (<NUM> uL) was loaded into "background wells", and Reaction Mix was loaded into "NADt" and "Decomposed sample" wells. The plate was incubated at room temperature for <NUM> minutes, and <NUM> uL NADH developer solution was added to the "Decomposed sample" wells. Absorbance readings were taken at <NUM> intervals over <NUM> at <NUM>.

Demographics and statistical analysis of a clinical observational study of adult NPC patients treated with ADLL: The cohort comprised <NUM> females and <NUM> males. Consent from all participants was obtained. Twelve of the NPC patients were on miglustat therapy (minimum exposure <NUM>, <NUM>st quartile <NUM>, median <NUM>, mean <NUM>, <NUM>rd quartile <NUM> and maximum <NUM> years). The thirteen NPC1 patients participated in an observational study treated with <NUM>/day acetyl-DL-leucine (Tanganil™). Three patients had four prospective clinical severity score measurements and ten patients had five measurements taken during this observational study (NIH, CSS). Retrospective data were used to calculate rates of disease progression prior to recruitment to this study. The mean age at the start of acetyl-DL-leucine (Tanganil™) treatment was <NUM> years. The minimum age was <NUM>, <NUM>st quartile <NUM>, median <NUM> and third quartile <NUM> with maximum age <NUM> years. The time in the observational treatment study was a mean of <NUM>, <NUM>st quartile <NUM>, median <NUM>, mean <NUM>, third quartile <NUM> and maximum <NUM> years.

Observational studies in GM2 gangliosidosis Patients: In a prospective observational case series in three patients with genetically proven GM2 gangliosidoses (<NUM> patients with Tay-Sachs disease, <NUM> patient with Sandhoff disease) the symptomatic effects of ADLL was evaluated. Patients were treated with <NUM> per kg body weight per day, for at least four weeks and the clinical effects determined using the Scale for the Assessment and Severity of Ataxia (SARA), the <NUM>-meter walk test (8MWT) and the Montreal Cognitive Assessment (MoCA). Consent from all participants was obtained.

A <NUM>-yearsold male patient with a genetically confirmed diagnosis of Tay-Sachs disease presented with dysarthrophonia, tremor, ataxia of stance and gait, paraparesis, and muscular atrophy. Prior to treatment, the patient required the support of both a caregiver on one side and a wall on the other in order to walk down a corridor. The patient was receiving sodium-valproate (<NUM>/d), lithium (<NUM>/d), and risperidone (<NUM>/d) (medications for clinically diagnosed bipolar disorder), and continued to do so during treatment with N-Acetyl-DL-Leucine. The patient was also receiving physiotherapy, ergotherapy, and logotherapy twice a week.

A <NUM>-year-old female patient with a genetically confirmed diagnosis of Tay-Sachs disease presented with ataxia of stance and gait, fine motor impairment, paraparesis of lower extremities and muscular atrophy. She was receiving physiotherapy, ergotherapy and logotherapy and continued to do so during treatment with N-Acetyl-DL-Leucine.

An <NUM>-year-old male patient suffering from Sandhoff disease, with muscle hypotrophy, epileptic cramps (tonic-clonic, about <NUM> seconds, self-limiting), disordered ocular movement and anarthria. His daily activities were very limited, being unable to eat, wash, or dress himself. He was receiving levetiracetam (<NUM>/d), lamotrigine (<NUM>/d), omeprazole (<NUM>/d), and miglustat (<NUM>/d), in addition to physiotherapy, ergotherapy and logotherapy, and continued to do so during treatment with N-Acetyl-DL-Leucine.

Differences between groups were identified either by <NUM>-way or <NUM>-way analyses of variances (ANOVA); comparisons of groups were made after <NUM>-way ANOVAs with Fisher's LSD test. Statistical tests were performed using GraphPad Prism <NUM> software (La Jolla, CA).

Npc1-/- mice have a <NUM>-<NUM>-week life span, with onset of symptoms (gait abnormalities, tremor and weight loss) beginning at <NUM>-<NUM> weeks of age. ADLL, ALL, and ADL were administered to Npc1-/- mice in the diet (<NUM>/kg/day), a dose similar to that used in observational clinical studies. Untreated <NUM>-week-old Npc1-/- mice exhibit statistically significant (p <<NUM>) ataxia that presents as a sigmoidal gait, relative to wild-type mice, whereas <NUM>-week-old Npc1-/- mice treated with ADLL, ALL or ADL from <NUM>-weeks of age (<NUM> week of treatment) all displayed significantly reduced ataxia as determined by measuring lateral displacement from a straight trajectory in an automated gait analysis system (<FIG> and <FIG>) (p <<NUM>, all treatments).

Npc1-/- mice were treated pre-symptomatically from weaning (<NUM> weeks of age) and assessed at <NUM> weeks of age (<NUM> weeks of treatment). ADLL, ALL, and ADL significantly reduced the magnitude of ataxia (<FIG> and <FIG>) with the magnitude comparable to the effects observed with one week of treatment.

Npc1-/- mice develop motor dysfunction (measured by Rotarod) and paw placement abnormalities when ambulatory (measured with CatWalk). Npc1-/- mice were treated pre-symptomatically from weaning (<NUM> weeks of age) and assessed the mice at <NUM> weeks of age. Untreated Npc1-/- mice had a significantly increased hind paw duty cycle (<FIG>) (percentage of hind paws in contact with the platform relative to the elapsed time between two consecutive contacts of the same paw) and a reduced hind paw stand mean (average duration of paw in contact with the platform) relative to wild-type mice. Pre-symptomatic ADLL and ALL treatment of Npc1-/- mice resulted in a significantly reduced (functional improvement) duty cycle of hind paws (ADLL: p = <NUM>, ALL: p <<NUM>) (<FIG>) and hind paw stand mean (indicative of functional improvement) (ADLL: p = <NUM>, ALL: p = <NUM>) relative to untreated Npc1-/- mice (<FIG>). Rotarod performance was significantly impaired in untreated Npc1-/- mice relative to wild-type littermates (p <<NUM>). Treatment with ADLL (p = <NUM>) and ALL (p = <NUM>) resulted in a significant improvement in Rotarod performance by Npc1-/- mice (<FIG>). ADL treatment had no significant benefit on Npc1-/- mouse motor function, as assessed using Catwalk (p <<NUM>) or Rotarod (p = <NUM>), suggesting that the D enantiomer has no benefit on these specific functional parameters. Relative to untreated Npc1-/- mice, the life span of animals treated from weaning was significantly increased by <NUM> days (<NUM>%) with ALL treatment (p = <NUM>), <NUM> days with ADLL (p = <NUM>) (<NUM>%) and was not changed with ADL (p = <NUM>) (<FIG>).

In light of the benefits of ADLL and ALL on gait, motor function and survival when treatment was initiated in the pre-symptomatic period, the impact of ALs on lipid storage in Npc1-/- mice was evaluated. Since NPC1 disease is characterized by the accumulation of sphingoid bases (sphingosine and sphinganine), cholesterol, sphingomyelin, free fatty acids and glycosphingolipids (GSLs), the impact of ALs administered to Npc1-/- mice from <NUM> weeks of age measuring lipid storage in brain was measured. At <NUM> days of age Npc1-/- mice exhibited increased lipid levels relative to wild-type (<FIG>, <FIG>, <FIG>, <FIG>, <FIG>). In order to evaluate the differential impact of the AL analogues in the CNS, the cerebellum and the forebrain (referred to as brain in the figures) were measured separately. Total GSLs in the forebrain were not significantly altered by any of the AL treatments (<FIG>), whilst ALL selectively reduced GM1a (<NUM>%; p = <NUM>) and GM2 (<NUM>%; p = <NUM>) (<FIG>). Interestingly, although sphingosine levels were not significantly affected, ADLL and ADL reduced sphinganine levels by <NUM>% (p = <NUM>) and <NUM>% (p = <NUM>) respectively (<FIG>). Analysis of the cerebellum confirmed there was no significant difference in total GSLs relative to untreated Npc1-/- mice with any of the AL analogues tested (<FIG>). However, ADLL and ALL treatment significantly lowered levels of specific GSLs including GA2 (ADLL: <NUM>%, p = <NUM>; ALL: <NUM>%, p = <NUM>), whereas a significant reduction in GA1 was only observed with ALL treatment (<NUM>%, p = <NUM>) (<FIG>). Comparable to the results for the forebrain, sphingosine was unchanged in the cerebellum, but sphinganine was significantly reduced following ADL treatment (<NUM>%, p = <NUM>) (<FIG>).

Npc1-/- mice exhibit progressive neurodegeneration, with cerebellar Purkinje cell loss progressing from anterior to posterior lobes, accompanied by microglial activation. ADLL treatment increased Purkinje cell survival at <NUM> days of age relative to untreated Npc1-/- littermates: <NUM>% more Purkinje cells were present in lobules I and II (p = <NUM>), and <NUM>% more Purkinje cells in lobule III (p = <NUM>) (<FIG>). Other treatments did not significantly improve Purkinje cell survival in any cerebellar lobules (Npc1-/-ALL Lobule I-IIp = <NUM>, Lobule III p = <NUM>, Lobule IV-V p = <NUM>; Npc1-/- ADL Lobule I-II p = <NUM>, Lobule III p = <NUM>, Lobule IV-V p = <NUM>, compared to Npc1-/- UT) (<FIG>). In addition, only ALL treatment significantly reduced (by <NUM>%, p = <NUM>) the frequency of CD68 positive activated microglia (<FIG>) while other treatments did not have a significant impact (p = <NUM> for Npc1-/- ADLL, p = <NUM> for Npc1-/-ADL compared to Npc1-/- UT). ADL did not mediate any long term, neuroprotective effects.

Liver GSL levels in the Npc1-/- mice were significantly reduced in Npc1-/- mice treated with ADLL (<NUM>%, p = <NUM>), ADL (<NUM>%, p = <NUM>) and <NUM>% for ALL (p = <NUM>) (<FIG>). Quantification of the major GSL species confirmed that levels of GM2Gc (the most abundant GSL in the mouse liver) was decreased significantly with all AL analogues tested (<NUM>% ADLL: p = <NUM>, <NUM>% ALL: p <<NUM>, <NUM>% ADL: p <<NUM>), while GM3Gc levels were only reduced significantly by ALL (<NUM>%: p = <NUM>) relative to untreated Npc1-/- mice (<FIG>). All analogues tested caused significant and comparable levels of reduction of sphingosine (the catabolic break down product of ceramide) (ADLL <NUM>%, p = <NUM>; ALL <NUM>%, p = <NUM>; ADL <NUM>% p = <NUM>) and its de novo precursor sphinganine (ADLL <NUM>% p = <NUM>; ALL <NUM>% p = <NUM>; ADL <NUM>% p = <NUM>) (<FIG> and <FIG>). Total free cholesterol in Npc1-/- liver was also significantly decreased after treatment with ADLL, ALL or ADL (ADLL <NUM>% p = <NUM>; ALL <NUM>% p = <NUM>; ADL <NUM> % p = <NUM>) (<FIG>). To explore whether other non-neuronal cell types were corrected by ALs the lysosomal volume as a surrogate for storage in Npc1-/- Chinese Hamster Ovary (CHO) cells was evaluated. Treatment with <NUM> ADLL and ALL reduced relative lysosomal volume after <NUM> (ADLL <NUM>%, p = <NUM>; ALL <NUM>%, p = <NUM>); however, this beneficial effect was seen with all three acetyl leucine treatments after <NUM> of treatment (ADLL <NUM>% p = <NUM>; ALL <NUM>% p = <NUM>; ADL <NUM> % p = <NUM>) (<FIG>). After <NUM> hours AL treatment sphingosine levels were significantly reduced by <NUM>% with ADLL (p = <NUM>), <NUM>% with ALL (p <<NUM>) and <NUM>% with ADL (p = <NUM>) (<FIG>). Total GSL levels were significantly reduced with all treatments to a comparable extent (<NUM>% with ADLL p = <NUM>; <NUM>% with ALL p = <NUM>; and <NUM>% with ADL p = <NUM>) (<FIG>). Likewise, cholesterol content was significantly reduced (<NUM>% with ADLL p = <NUM>; <NUM>% with ALL p = <NUM>; and <NUM>% with ADL p = <NUM>) (<FIG>).

Npc1-/- mice were treated with ADLL in combination with the standard of care drug miglustat, resulting in a statistically significant longer life span than animals on monotherapy (Npc1-/- miglustat vs Npc1-/- miglustat & ADLL p = <NUM>; Npc1-/- ADLL vs Npc1-/- miglustat & ADLL p = <NUM>; median survival; Npc1-/-UT: <NUM> days, Npc1-/- / ADLL: <NUM> days; Npc1-/- miglustat: <NUM> days, Npc1-/- miglustat & ADLL: <NUM> days) (<FIG>). Miglustat is known to cause weight loss through appetite suppression. When ADLL was used in combination with miglustat it prevented the weight loss associated with miglustat treatment (<FIG>) but not the weight loss resulting from progression of the disease. Combination therapy significantly increased Rotarod test performance (<NUM> weeks: p = <NUM>; <NUM>,<NUM> weeks p <<NUM> versus untreated Npc1-/-), with combination therapy associated with increased benefit relative to mice receiving either miglustat (<NUM> weeks: p = <NUM>; <NUM> weeks: p = <NUM>) or ADLL monotherapy (<NUM>,<NUM> weeks: p <<NUM>) (<FIG>). Gait analysis at <NUM> weeks of age demonstrated that hind Duty Cycle percentages were significantly improved with combination therapy (p = <NUM>) whereas miglustat monotherapy showed no benefit (<FIG>). Stand mean significantly improved in mice treated either with combination therapy (p = <NUM>) or miglustat monotherapy (p = <NUM>) (<FIG>).

Unexpected beneficial effects of ALs in Npc1-/- mice were discovered. Whether neuroprotective effects also occur in NPC patients treated with ADLL enrolled in an observational clinical study was investigated. Total clinical severity scores (maximum score <NUM>, with higher values equating to increasing levels of disability) were plotted prior to initiation of treatment with Tanganil™, including available retrospective data (<FIG>). All <NUM> patients had positive slopes of disease progression before ADLL treatment (<NUM> severity units/year was the average slope). Following initiation of ADLL treatment the average slope was -<NUM> (<NUM> patients had no slope, <NUM> had negative slopes) equating to a significant reduction in disease progression and improvement in the majority of patients (One-sided sign test p = <NUM>). The data were also computed as Annual Severity Increment Scores that measures the rate of disease progression and a mean of -<NUM>% / year (p <<NUM>) in ASIS scores was observed. When the treated patient data were analysed by neurological subdomain the majority of patients improved or stabilised on treatment, irrespective of the neurological subdomain measured (Table <NUM>).

The Sandhoff (Hexb-/-) mouse model is pre-symptomatic up to <NUM>-<NUM> weeks of age. Subsequently, these mice develop tremor and their motor function begins to decline. By the later stages of the disease (<NUM>-<NUM> weeks) they are inactive and are unable to complete motor function tests such as bar crossing. Hexb-/- animals were treated from weaning with ADLL (<NUM>/kg/day, the same dose used for treatment of Npc1-/- mice). Extended survival, with a median increase in lifespan of <NUM> days (p = <NUM>) (<FIG>) was observed. Bar-crossing test performance also significantly improved (<NUM> weeks: p = <NUM>; <NUM> weeks: p = <NUM>), which is indicative of delayed deterioration in motor function (<FIG>).

These findings in Sandhoff mice were extended to observational clinical studies in three patients with a confirmed GM2 gangliosidosis diagnosis (<NUM> Tay-Sachs and <NUM> Sandhoff disease) treated with ADLL. A mean improvement of the Scale for Assessment and Rating of Ataxia (SARA) by <NUM>%, the <NUM>-M-Walking-Test (8MWT) by <NUM>% and the Montreal Cognitive Assessment (MoCA) by <NUM>% was found as shown in the <FIG>. All patients and caregivers also reported a subjective improvement and are still on treatment at the same dosage.

Claim 1:
Acetyl-leucine and miglustat for use in a method of treating a lysosomal storage disease in a subject in need thereof, the method comprising administering a combination of:
(i) a therapeutically effective amount of acetyl-leucine; and
(ii) a therapeutically effective amount of miglustat,
to the subject, wherein subject is naive to treatment with miglustat.