Dosage regimen for 2-butyl-9-methyl-8-(2h-1,2,3-triazol-2-YL)-9h-purin-6-ylamine for the entrainment of circadian rhythm

Abstract

2-butyl-9-methyl-8-(2H-1,2,3-triazol-2-yl)-9H-purin-6-ylamine for use in the entrainment of circadian rhythm in a human subject in need thereof.

Description

[0001] DOSAGE REGIMEN FOR -BUTYL-9-METHYL-8-(2H-1 ,2,3-TRIAZOL-2-YL)-9H-PURIN-6-YLAMINE FOR THE

[0002] ENTRAINMENT OF CIRCADIAN RHYTHM

[0003] This application claims priority to and the benefit of United Kingdom Patent Application No. GB 2319534.0, filed on 19 December 2023, the contents of which are incorporated by reference.

[0004] The disclosure relates to the use of a particular dosage regimen of an adenosine receptor modulator to entrain circadian rhythm. In particular the adenosine receptor modulator is 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine, also referred to as CT1500. The disclosure particularly relates to the entrainment of the circadian rhythm in human subjects.

[0005] Almost all organisms on Earth apply an internal biological timer to anticipate changes that accompany the daily solar cycle. The possession of such an internal timer allows organisms to inherently "know" where in the daily solar cycle they are, absent of external cues. Such internally generated daily rhythms are called "circadian rhythms" and are endogenous to the organism.

[0006] The mechanisms underlying circadian rhythms involve circadian oscillations in processes such as gene expression and protein modifications. A core clock controls these circadian oscillations by signal generation.

[0007] The mammalian circadian clock in the brain conveys 24-hour rhythmicity to rest-activity cycles, temperature, sleep, and virtually all other behavioural and physiological processes. The imposition of an internal temporal framework is an essential part of an organism's biology; it allows all of the internal processes to work in harmony, such as gene expression, cell division and metabolism. In order for such rhythms to be adaptive, they must be synchronised, or entrained, to the external environment, predominantly produced by the 24-hour light / dark cycle due to the rotation of the Earth, and / or to other entraining signals, known as "time givers" or zeitgebers. It is key that circadian rhythms are generated internally by the organism and are not driven by the external environment. However, these endogenous circadian rhythms are adjusted by environmental signals, such that they are synchronised to the external cycle or clock.

[0008] In the absence of external cues or signals, the endogenous circadian rhythm in a human, on average, runs slightly longer than 24 hours. This may be the case in totally blind subjects who are lacking conscious light perception, where the complete absence of detection of the light / dark cycle may be sufficient for the clock to run free of adjustment based on external signals. In these cases, the circadian rhythm may require realignment, such that the internal clock is running at the same time as the external one. This state can be induced in a laboratory setting by housing animals, for example mice, in constant darkness.

[0009] The internal circadian clock has its own time, known as circadian time (CT); which is a standard of time based on the free-running period of a rhythm (oscillation). This may or may not be aligned with the external / environmental time. CT is effectively the internal time (either for the whole clock or the relevant tissue). Time relative to the external environment is denoted as ZT or Zeitgeber time. Under entrained conditions, CTO = ZTO = start of the light phase (typically 6 or 7 am) and under free-running conditions, CTO in a human would be the time at which the onset of activity occurs. Determining the CT of a tissue or individual is possible via testing.

[0010] Zeitgeber time (ZT) is a standardised 24 hour notation of time, in which ZTO indicates the beginning of the day or light cycle, and ZT12 is the beginning of the night or dark phase (in a 12:12 light:dark cycle). In terms of circadian time, it is gene rally the case that CTO indicates the beginning of a subjective day, and CT12 is the beginning of a subjective night. The mechanism underlying the clock is a ubiquitous cell autonomous transcriptiontranslation feedback loop (TTFL) in which the transcription factors CLOCK and BMALl drive the expression of Period (Perl / 2) and Cryptochrome (Cryl / 2), whose protein products in turn feedback to inhibit CLOCK and BMALl resulting in a negative feedback loop within a 24-hour period.

[0011] Each individual cell of an organism has an individual cellular clock. Individual cellular clocks are maintained in synchrony by a master pacemaker in the suprachiasmatic nuclei (SCN) in the hypothalamus. In order to adapt to the external 24-hour world, the clock must receive and respond to signals that provide temporal cues (zeitgebers). Zeitgebers modulate the temporal expression pattern of clock genes such as Perl / 2 (Schwartz et a!., Proc Natl Acad Sci USA 108, 17219-17224, 2011) to set the phase, amplitude and period of oscillation of the molecular clock. Light, which signals the dawn-dusk cycle, drives cAMP response element binding factor (CREB)-mediated transcription of Per genes. However, circadian clocks throughout the body receive inputs from numerous sources including food, glucocorticoids and temperature. The molecular clock receives environmental input through ligands that bind to cell-surface and nuclear receptors and activate downstream signalling pathways that converge on the TTFL. While a few of these pathways are known (e.g., NMDA receptors signal light input to the SCN), the majority remain unknown.

[0012] The process of synchronisation of the timekeeping mechanism to the environment, such as the light-dark cycle, is generally termed entrainment. A subject is described as "free- running" if they have an absence of any entraining stimuli, such as light.

[0013] It is possible for cells and / or tissues of the body to have a circadian rhythm that has desynchronised with the central or SCN rhythm. In this scenario, the cells and / or tissues are running with a different rhythm to the rest of the body. This can result in pathologies developing in those cells and tissues, since inappropriately timed physiological processes are undertaken. For example, it has been shown that a "faulty" or misaligned circadian clock in pancreatic tissues may be related to the development of diabetes. (Disruption of the clock components CLOCK and BMAL1 leads to hypoinsulinaemia and diabetes, Marcheva et al, Nature, 466, 627-631, July 2010).

[0014] When an internal de-synchrony occurs between a person's biological clock and their environmental 24-hour schedule, a group of pathologies known as circadian rhythm disorders can occur. This de-synchronisation can occur in the SCN, and thus the circadian rhythm of the whole body, or can occur in selected tissues peripheral to the SCN as described above. It is possible for either central or peripheral de-synchronisation to occur without any manifest symptoms. Where the circadian rhythm of a subject is not synchronised to the external / environmental clock, it can be said to be free-running. Ultimately, since a free-running clock can be up to one hour longer than the external clock in illustration, every 12 days, the subject's circadian rhythm will be completely antiphase to the outside world and will experience extreme jet-lag symptoms.

[0015] Where the circadian rhythm and the external / environmental clock are de-synchronised, this can have many physiological and behavioural impacts. Several circadian rhythm dysfunctions may result from the lack of synchrony with the external clock.

[0016] In some instances, de-synchronisation of a person's SCN circadian rhythm may be detected since the rest-activity rhythm changes. The timings of rest and activity can be measured using an actimetry sensor, for example. A correlation has been shown between the non-entrained drift in the circadian phase and the non-24-h component of the rest-activity rhythm in subjects when wrist actigraphy data analysed. There is a possibility that chronic circadian misalignment could also result in adverse metabolic, cognitive, and emotional consequences in subjects with non-24h disorder (Emens, Jonathan S. et al. "Non-24-Hour Disorder in Blind Individuals Revisited: Variability and the Influence of Environmental Time Cues." Sleep 36.7 (2013): 1091-1100. PMC. Web. 7 Apr. 2017). Circadian rhythm misalignment or dysfunctions may be introduced into an individual, such as through pharmacological intervention. For example, it has been shown that some cancer treatments are capable of altering the circadian rhythm (Ortiz-Tudela E., et al, Int. J Cancer. 2014 Jun l;134(ll):2717-25.) Such dysfunctions in the circadian rhythm may be correlated with poorer outcomes for treatment, and thus it is important that these are recognised and addressed. In converse, it is also known that some proteins targeted by pharmacological agents are expressed only during certain times of day and this may be out of the patient's wake time (e.g. 3am). Under this circumstance it would be of use to alter the circadian rhythms to align the "drug-time" to the wake time.

[0017] Circadian rhythm misalignment may also occur when individuals travel across time zones. Jet lag, also described as desynchronosis and circadian dysrhythmia, is a physiological condition which results from rapid long-distance trans-meridian (eastwest or west-east) travel.

[0018] Further, circadian rhythm misalignment may occur for shift workers, who are working in the evening and overnight, since they are active during their normal rest cycle. Shift work disorder is a recognised circadian rhythm disorder.

[0019] Certain circadian rhythm disorders may be circadian rhythm sleep disorders, where the misalignment of the circadian clock manifests in the timing of sleep, which itself is determined from the rest-activity rhythm.

[0020] Current methods of treatment of circadian rhythm disorders primarily centre around bright light therapy and the use of melatonin receptor agonists. These methods have their drawbacks; they are not uniformly effective, for example, melatonin has not been shown to have any effect in Advanced Sleep Phase Syndrome or jet-lag in westward travel, and mixed outcomes are observed with Shift Work Disorder and non-24-h sleep disorders. Bright light therapy requires exposure to high levels of light (2,500- 10,000 lux) at precise time windows each day (reviewed in Zee et al., 2013, Circadian rhythm abnormalities. Continuum: Lifelong Learning in Neurology, 19(1, Sleep Disorders), 132- 147.) and for the subject to be sighted.

[0021] Whilst it is known that adenosine receptor antagonists, such as caffeine, can ameliorate the symptoms of circadian rhythm disorders by improving wakefulness, typical use of these antagonists is ineffective at entraining circadian rhythm. Without wishing to be bound by theory, it is thought that the exposure time for the antagonists is too long and therefore does not replicate the physiological cues that entrain the circadian rhythm.

[0022] It is disclosed in WO 2017 / 178820 Al (herein incorporated by reference) that antagonists selective for particular adenosine receptors, particularly the Ai and AZA receptors, are especially effective for treating circadian rhythm disorders in mice. Following from this work, the inventors of that application, supported by the present applicant, recently published the effect of the selective adenosine receptor antagonist CT1500 on the circadian rhythm of mice (Jagannath et al., 2022, The regulation of circadian entrainment in mice by the adenosine the AZA / AI receptor antagonist CT1500, Frontiers in Physiology, 13:1085217, herein incorporated by reference). These studies showed that only a high dose (20 mg / kg) of CT1500 delivered at the same time daily was able to effectively entrain the circadian rhythms of free-running mice. Studies also identified that that, in a dose-dependent manner, CT1500 could be used to more rapidly re-entrain the circadian rhythms of mice exposed to a sudden shift in external light cues, a scenario which replicates the effect of trans-meridian travel.

[0023] CT1500 therefore represents a promising candidate for entraining the circadian rhythm in humans, however the dosage which is sufficient to act as a zeitgeber but not so high as to mirror the effects found with caffeine remains to be resolved. This matter is complicated by the finding that the metabolic profile of CT1500 is particularly complex in humans.

[0024] Summary of the Invention According to a first aspect, the disclosure provides 2-butyl-9-methyl-8-(2H-l,2,3-triazol- 2-yl)-9H-purin-6-ylamine for use in the entrainment of circadian rhythm in a human subject in need thereof wherein 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6- ylamine is provided or delivered in a dose of 5-60 mg.

[0025] "Entrainment of circadian rhythm" means the shifting of CT relative to ZT. This includes shifting to restore a "natural" circadian rhythm wherein CTO is approximately equal to ZTO, however it also includes shifting CTO to be approximately equal to a different ZT which may be desirable for some other reason. "Entrainment of circadian rhythm" may also mean maintaining a circadian rhythm that would otherwise be subject to shift. For example, in patients with otherwise free-running circadian rhythms "entrainment of circadian rhythm" includes both shifting the patient's CTO to a desired ZT and also keeping it there.

[0026] "A human subject in need thereof" means any human who needs or is desirous to shift their CT relative to ZT. In particular it includes but is not limited to: subjects who would otherwise have a free-running or non-entrained circadian rhythm, subjects who have no ability to sense light, subjects who are anopthalmic, subjects who are in an environment where there is insufficient light to entrain circadian rhythm to a 24h cycle, subjects who are shift workers, subjects who have jet-lag disorder, subjects who are receiving an additional treatment and wherein the additional treatment benefits from delivery at a particular point in the subjects circadian rhythm, subjects who have Major Depressive Disorder, subjects who have Major Psychoses, and subjects who have schizophrenia.

[0027] "A dose of 5-60 mg" means 5-60 mg, delivered in effectively a single administration. The dose may be administered through any appropriate route. In an embodiment the dose may be administered orally, for example orally through tablets, or equivalents as described herein, and may be delivered via one single tablet or via more than one smaller tablet wherein the total dose is between 5 and 60 mg. Depending on the need of the subject, the dose of 5-60 mg may be delivered at a particular time of day. For example, for entrainment of circadian rhythm to a 24h cycle or generally for advancing the phase of the subject's circadian rhythm the dose should be delivered in the morning. If the subject needs to delay the phase of their circadian rhythm, for example for shift work, they should take the dose in the evening. Thus, the dose may be administered at or around ZTO (morning) or at or around ZT12 (evening).

[0028] For eastward trans-meridian travel the subject should take the dose at a time equivalent to the morning in the destination time zone. For westward trans-meridian travel the subject should take the dose at a time equivalent to the evening in the destination time zone.

[0029] Thus, the dose may be administered at any appropriate time, depending on the desired entrainment of the circadian rhythm. The dose may thus be administered at any one of ZT1, ZT2, ZT3, ZT4, ZT5, ZT6, ZT7, ZT8, ZT9, ZT10, ZT11, ZT12, ZT13, ZT14, ZT15, ZT16, ZT17, ZT18, ZT19, ZT20, ZT21, ZT22, ZT23 or ZT24, or any interval between these times.

[0030] The dose may be administered to a human. The dose may be administered to a human subject in need of entrainment of a circadian rhythm. Suitable human subjects are described further herein.

[0031] 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine (CT1500) is a known adenosine receptor antagonist with ECso values of 103 nM and 8 nM against Ai and AZA receptors, respectively. In vivo, CT1500 is metabolised into active metabolites 4-[6- amino-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-2-yl]-2-butanone (CT1517) and 4-[6- amino-9-methyl-8-(triazol-2-yl)purin-2-yl]butan-2-ol (CT1518), both of which are also potent Ai and AZA receptor antagonists. (Stasi et al., 2015, Animal models of Parkinson's disease: Effects of two adenosine AZA receptor antagonists ST4206 and ST3932, metabolites of 2-n-Butyl-9-methyl-8-[l,2,3]triazol-2-yl-9H-purin-6-ylamine (ST1535), European Journal of Pharmacology, 761:353-361). CT1500 may be referred to by synonymous nomenclature for example CT-1500, 2-butyl-

[0032] 9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-amine, 2-butyl-9-methyl-8-[l,2,3]triazol-

[0033] 2-yl-9H-purin-6-ylamine, 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6- xylamine and ST1535. The structures of CT1500, and the active metabolites CT1517 and

[0034] CT1518 are given below for the avoidance of any doubt.

[0035] An 'adenosine receptor' is a class of purigenic G protein-coupled receptors with adenosine as an endogenous ligand. These receptors are widely distributed throughout the body and are divided into four subclasses, which include Ai, AZA, AZB and A3 adenosine receptors. Adenosine functions as a signalling molecule through the activation of these four distinct adenosine receptors, which are widely expressed and have been implicated in several biological functions, both physiological and pathological. Adenosine receptors occur as four different subtypes of GPCRs, with the Gscoupled AZA and AZB receptor subtypes and the Gi coupled Ai and A3 receptor subtypes. Differential expression of these receptors can lead to very different downstream effects of adenosine signalling through diverse effectors.

[0036] It has been demonstrated that, high doses of CT1500 do not entrain the circadian rhythm and produce similar effects as, for example, caffeine. The present inventors have found through clinical pharmacokinetic studies that the metabolism of CT1500 and elimination of CT1517 and CT1518 is complex and non-linear. Administration of CT1500 within the dose range 5-60 mg produces a surprisingly potent but short-lived antagonism of adenosine receptors which is particularly effective at entraining circadian rhythm in a human subject.

[0037] It has been found, in the 5-60 mg dose range in a human subject CT1500 is rapidly metabolised into CT1517 and CT1518 such that plasma concentrations of CT1500 are minimal. In this dosage range the length of time the plasma concentrations of CT1500, and / or its active metabolites, such as CT1517 and CT1518, exceed the Ki for Ai and AZA is less than 5 hours which fulfils the requirements of being a short-acting adenosine receptor antagonist, thereby rendering it effective for use in the entrainment of circadian rhythm in a human subject in need thereof. At a dosage of greater than 60 mg, for example 120 mg, CT1500 is metabolised much more slowly such that the plasma concentrations of CT1500, and / or its active metabolites, such as CT1517 and CT1518, are orders of magnitude higher, compared with a 5-60 mg dose range. Suitably, at a dosage of greater than 60 mg, for example 120 mg, the plasma concentrations of CT1500, and / or its active metabolites, such as CT1517 and CT1518, can exceed the Ki for Ai and AZA receptors for over 10 hours. This is comparable with the pharmacokinetics of caffeine and is not effective at entraining circadian rhythm. It appears that, surprisingly, CT1500 inhibits its own metabolism at a dosage of greater than 60 mg and therefore exhibits unpredictable pharmacokinetic behaviour. There is thus a critical dosage threshold below which CT1500 is effective as a short-acting adenosine receptor anatagonist that renders it effective for use in the entrainment of circadian rhythm in a human subject in need thereof. This was entirely unexpected.

[0038] The term 'Ki' means the inhibition constant (also known as the inhibitory constant) and is a measure of the equilibrium binding affinity for a ligand, such as a drug, that reduces the activity of its binding partner, such as a receptor. Ki represents the concentration (typically expressed in nanomoles) at which the ligand occupies 50% of the receptor sites. The smaller the Ki for a particular ligand at a particular receptor, the stronger its binding affinity for that receptor and a smaller amount of ligand is needed to inhibit its binding receptors activity.

[0039] The length of time (i.e. duration) the plasma concentration of CT1500, and / or its active metabolites, such as CT1517 and / or CT1518, exceeds the Ki for Ai and / or AZA receptor(s) may be determined using routine techniques known to those skilled in the art, by comparing the concentration of the respective ligand (e.g. CT1500, CT1517 and CT1518) present in human plasma at various time points following administration (e.g. by serial blood sampling post administration and standard pharmacokinetic sampling) with the known Ki value for Ai and / or AZA receptor(s) for the respective ligand. In this respect, known Ki values for Ai and / or AZA receptor(s) for CT1500, CT1517 and CT1518 as reported by Stasi, Eur J Pharmacol. 2015 Aug 15;761:353 are detailed below:

[0040] The results of the experiments on phase shifting in mice (Jagganath et al, 2022) reported a bell-shaped relationship between CT1500 dose and the phase shift exhibited by the mice. However closer examination of suggests that the phase shift merely plateaued at higher dosages rather than becoming less effective. The authors note also that the different dosages did not produce statistically different results. Thus, the non-linear dose dependence shown here for humans could not have been predicted from the mouse models because the metabolism of CT1500 in mice differs quantitatively and qualitatively from that in humans. In particular, selection of doses based on the mouse models would result in administration of excess amounts of CT1500 and thus protracted exposure to adenosine receptor antagonists which would not be effective at entraining the subject's circadian rhythm.

[0041] The disclosure provides 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine for use in the entrainment of circadian rhythm in a human subject in need thereof wherein 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine is provided or delivered in a dose of 5 to 60 mg, or provided or delivered in a dose as disclosed herein, such as 5 to 45 mg, such as 5 to 30 mg, so as to provide a length of time (i.e. duration) the plasma concentration of CT1500 exceeds the Ki for Ai and AZA receptors of 5 hours or less, such as 4 hours or less, such as 3 hours or less, such as 2 hours or less, such as 1 hour or less.

[0042] The disclosure provides 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine for use in the entrainment of circadian rhythm in a human subject in need thereof wherein 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine is provided or delivered in a dose of 5 to 60 mg, or provided or delivered in a dose as disclosed herein, such as 5 to 45 mg, such as 5 to 30 mg, so as to provide a length of time (i.e. duration) the plasma concentration of CT1500, and / or its active metabolites, such as the active metabolite CT1517 and / or the active metabolite CT1518, exceed the Ki for Ai and AZA receptors of 5 hours or less, such as 4.5 hours or less, such as 4 hours or less, such as 3.75 hours or less.

[0043] The disclosure provides 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine for use in the entrainment of circadian rhythm in a human subject in need thereof wherein 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine is provided or delivered in a dose of 5 to 60 mg, or provided or delivered in a dose as disclosed herein, such as 5 to 45 mg, such as 5 to 30 mg, so as to provide an entrainment of circadian rhythm for a maximum period of up to 5 hours, such as up to 4.5 hours, such as up to 3.75 hours.

[0044] The disclosure provides a pharmaceutical composition comprising 2-butyl-9-methyl-8- (2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine, wherein the composition comprises 5 to 60 mg, such as 5 to 45 mg, such as 5 to 30 mg, 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)- 9H-purin-6-ylamine. The pharmaceutical composition can be for use in the entrainment of circadian rhythm, as defined herein, in a human subject in need thereof, as defined herein. The 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine may be present in the pharmaceutical composition in an amount as disclosed herein.

[0045] The disclosure provides the use of 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin- 6-ylamine in the manufacture of a medicament for treating a human subject, as defined herein, to entrain their circadian rhythm, as defined herein, wherein the medicament comprises 5 to 60 mg, such as 5 to 45 mg, such as 5 to 30 mg, 2-butyl-9-methyl-8-(2H- l,2,3-triazol-2-yl)-9H-purin-6-ylamine. The 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)- 9H-purin-6-ylamine may be present in the medicament in an amount as disclosed herein.

[0046] The disclosure provides a method of treating a human subject, as defined herein, to entrain their circadian rhythm, as defined herein, the method comprising administering 5 to 60 mg, such as 5 to 45 mg, such as 5 to 30 mg, 2-butyl-9-methyl-8-(2H-l,2,3-triazol- 2-yl)-9H-purin-6-ylamine to the human subject. The 2-butyl-9-methyl-8-(2H-l,2,3- triazol-2-yl)-9H-purin-6-ylamine may be administered to the human subject in an amount as disclosed herein. The disclosure provides a means for entraining circadian rhythm in a human subject, as defined herein, for 5 hours or less, such as 4.5 hours or less, such as 4 hours or less, such as 3.75 hours or less.

[0047] The disclosure may provide a dose or the delivery of a dose of 2-butyl-9-methyl-8-(2H- l,2,3-triazol-2-yl)-9H-purin-6-ylamine in an amount of 60 mg or less, such as 55 mg or less, such as 50 mg or less, such as 45 mg or less, such as 40 mg or less, such as 35 mg or less, such as 30 mg or less.

[0048] The disclosure may provide a dose or the delivery of a dose of 2-butyl-9-methyl-8-(2H- l,2,3-triazol-2-yl)-9H-purin-6-ylamine in an amount of 5 mg or more, such as 7.5 mg or more, such as 10 mg or more, such as 12.5 mg or more, such as 15 mg or more.

[0049] The disclosure may provide a dose or the delivery of a dose of 2-butyl-9-methyl-8-(2H- l,2,3-triazol-2-yl)-9H-purin-6-ylamine in an amount of 5 to 60, such as 5 to 55, such as 5 to 50, such as 5 to 45, such as 5 to 40, such as 5 to 35, such as 5 to 30, such as 7.5 to 60, such as 7.5 to 55, such as 7.5 to 50, such as 7.5 to 45, such as 7.5 to 40, such as 7.5 to 35, such as 7.5 to 30, such as 10 to 60, such as 10 to 55, such as 10 to 50, such as 10 to 45, such as 10 to 40, such as 10 to 35, such as 10 to 30, such as 12.5 to 60, such as 12.5 to 55, such as 12.5 to 50, such as 12.5 to 45, such as 12.5 to 40, such as 12.5 to 35, such as 12.5 to 30, mg.

[0050] Suitably, the human subject is an adult male and / or adult female subject of 16 years or more age. Suitably, the human subject, such as an adult male and / or adult female subject, may have a weight of 35 or more, such as 40 or more, such as 45 or more, kg. Suitably, the human subject, such as an adult male and / or female subject, may have a weight of 90 or less, such as 85 or less, such as 80 or less, kg.

[0051] The disclosure may provide a dosage of 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H- purin-6-ylamine and / or active metabolites, such as CT1517 and CT1518, thereof for use in the entrainment of a circadian rhythm in a human subject wherein the total blood concentration of 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine and / or its active metabolites reaches between 1 and 100 ng / mL. Preferably, the total blood concentration of 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine and its active metabolites, such as CT1517 and CT1518, reaches between 1 and 100 ng / mL. As described in the Examples, a dosage of 5-60mg CT1500 may achieve these total blood concentrations in a human. Measurements of total blood concentration are preferably recorded around 90 minutes after oral administration. Alternative modes of administration will necessarily have varying rates of uptake.

[0052] The disclosure may provide 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6- ylamine for use at the dosage described wherein the subject in need thereof would otherwise have a free-running or non-entrained circadian rhythm.

[0053] A "free-running" circadian rhythm means a circadian rhythm that is not affected by external cues and therefore proceeds only under its own mechanisms. Such circadian rhythms are typically longer than 24 hours, closer to 25 hours, and therefore subjects with free-running circadian rhythms phase in and out of alignment with ZT over the course of roughly a month. A "non-entrained" circadian rhythm means a circadian rhythm that is not aligned to the desired ZT. This embodiment includes use by subjects who, by virtue of the use of CT1500, no longer have a free-running or non-entrained circadian rhythm but who previously had a free-running or non-entrained circadian rhythm and would be expected to return to that state if they stopped using CT1500.

[0054] The disclosure may provide 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6- ylamine for use at the dosage described wherein the subject has no ability to sense light.

[0055] A subject having no ability to sense light may be completely blind because of a genetic condition, degenerative disease, trauma or any other circumstance which leads to complete loss of photoreception. Some subjects who are functionally blind still possess the ability to sense light and receive zeitgebers to entrain their circadian rhythm. The light sensing cells which regulate the SCN are distinct from the rods and cones which feed the visual cortex. A subject can therefore be functionally blind but still have a standard circadian rhythm regulated by external light cues. These subjects can sense light, and therefore fall outside the definition of the subject in this scenario.

[0056] The disclosure may provide 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6- ylamine for use at the dosage described wherein the subject is anopthalmic. Anopthalmic means having no eyes. This may be due to a developmental defect, trauma or other circumstance leading to lack of eyes.

[0057] The disclosure may provide 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6- ylamine for use at the dosage described wherein the subject is in an environment where there is insufficient light to entrain circadian rhythm to a 24h cycle.

[0058] The intensity of light necessary to entrain the circadian rhythm has been calculated to be around 1000-10,000 lux for an hour in the morning. Subjects in dark environments for long periods of time such as miners, deep-sea divers, submariners, subjects at high latitudes during winter, are unlikely to receive enough light at appropriate times to entrain their circadian rhythm and could therefore benefit from use of the present disclosure.

[0059] The disclosure may provide 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6- ylamine for use at the dosage described wherein the subject is sighted and needs reentrainment of their circadian rhythm to a new circadian rhythm.

[0060] "Sighted" means the subject can see and can detect light. The subject will therefore likely have a circadian rhythm that is entrained to the external cues of their environment wherein CTO is approximately equal to ZTO. The subject however needs or is desirous to shift their circadian rhythm to align with a different ZT.

[0061] The disclosure may provide 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6- ylamine for use at the dosage described wherein the subject is a shift worker. Shift workers are required to work non-standard hours, often during part of or the entirety of the night. Their working hours may be subject to frequent change and on days off they may wish to be awake during the day like non-shift workers. These unstable timings are incompatible with a static circadian rhythm entrained to external light cues. It is therefore of great value to shift-workers to be able to readily re-entrain their circadian rhythm to be more compatible with their schedules.

[0062] The disclosure may provide 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6- ylamine for use at the dosage described wherein the subject has jet-lag disorder or is preparing for upcoming trans-meridian travel. Jet-lag disorder caused by east-west or west-east trans-meridian travel can cause serious problems for travellers. Particular problems may arise for subjects travelling for business who may have important work to do but do not have time to naturally acclimatise to their new time zone. Use of CT1500 can aid by accelerating the re-entrainment of the subject's circadian rhythm to align with ZTO in the new time zone. Subjects may prefer to pre-empt their travel by use of CT1500 thereof at an appropriate time of day in the days before travel such that when they arrive at their destination their circadian rhythm is already correctly aligned.

[0063] The disclosure may provide 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6- ylamine for use at the dosage described wherein the subject is a patient receiving an additional treatment and wherein the additional treatment benefits from delivery at a particular point in the subject's circadian rhythm.

[0064] It is known that some treatments for some diseases or conditions are best delivered at particular points in a patient's circadian rhythm. If this optimum delivery time is during the day then there is not usually a problem because the patient may be able to selfadminister the treatment or others will be more available to assist them. If, however, the optimum delivery time is during the night this can cause problems such as interrupted sleep, lack of assistance to deliver the treatment. CT1500 can therefore be used to re-entrain a patient's circadian rhythm such that the optimum treatment delivery time occurs during a more convenient real time. This will necessarily have the consequence of the patient's circadian rhythm being out of alignment with ZT, however this will have to be weighed against the benefits to delivering the treatment at the optimum CT.

[0065] The disclosure may provide 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6- ylamine for use at the dosage described wherein the patient has cancer and the additional treatment is chemotherapy.

[0066] It has been found that CT 15 (10pm if synchronised with the external clock) may be an effective time to administer certain chemotherapy drugs (Levi F et al, Circadian timing in cancer treatments. Annu Rev Pharmacol Toxicol. 2010; 50:377-421.). This is not a socially acceptable time for the patient or physician to be administering drugs. Therefore, it is possible to re-entrain the patient's circadian rhythm, such that it is put out of synchrony with the external clock. Thus, the administration of selective modulator or composition may be used to shift the circadian rhythm clock to bring the effective CT time for treatment to a better external time.

[0067] The disclosure may provide 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6- ylamine for use at the dosage described wherein the patient has Parkinson's disease and the additional treatment is an approved treatment for Parkinson's disease.

[0068] Similarly to chemotherapy, some Parkinson's disease treatments are best delivered during the body's "off" state. However, during the "off" periods drugs such as levodopa are less efficacious due to the Blood Brain Barrier (BBB) kinetics (drug absorption and efflux). Given the BBB permeability is regulated by the circadian clock (Zhang et al., Nat Commun (2021); 12, 617) entrainment of the circadian rhythm can be used to change the phase of the BBB such that other drugs remain efficacious. Thus, the present disclosure may be utilised to make other drugs more effective in the treatment of Parkinson's disease.

[0069] The disclosure may provide 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6- ylamine for use at the dosage described wherein the subject has Major Depressive Disorder (MDD) or Seasonal Affective Disorder (SAD).

[0070] The fact that the phase of the clock is severely disturbed in a subpopulation of MDD and SAD patients is well described. Further, entraining the phase of their internal clock to match the external light-dark cycle (e.g., using light therapy) and stabilising their rhythm has been shown to improve their mood symptoms (Germain, et al., 2008. Hum Psychopharmacol; 23(7): 571-585). Therefore 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2- yl)-9H-purin-6-ylamine can be used to stabilise the patient's circadian rhythms to improve the mood of patients suffering from MDD or SAD.

[0071] The disclosure may provide 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6- ylamine for use at the dosage described wherein the subject has Major Psychoses or Schizophrenia.

[0072] As with MDD and SAD, several types of circadian rhythm disruption have been described in Schizophrenia (Wulff et al., 2012. Br J Psychiatry; 200(4):308-16. Further stabilising sleep and circadian disruption has been shown to reduce paranoid delusions in schizophrenia by up to 50%. Therefore, where patients' rhythms are disrupted, the dosage of the present disclosure could be used for rhythm stabilisation and reduction in psychosis and dilutions. Further, the disclosure provides a composition comprising 2-butyl-9-methyl-8-(2H-l,2,3- triazol-2-yl)-9H-purin-6-ylamine for use according to any previous aspect or embodiment wherein the composition comprises any of 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, T1 , 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39 or 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 or 60 mg 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine.

[0073] According to the present disclosure, the use relates to a dosage of 2-butyl-9-methyl-8- (2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine of 5-60mg. For the avoidance of doubt, such a range includes any of 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39 or 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 or 60 mg 2-butyl-9-methyl-8-(2H-l,2,3- triazol-2-yl)-9H-purin-6-ylamine

[0074] The disclosure may provide a composition comprising 2-butyl-9-methyl-8-(2H-l,2,3- triazol-2-yl)-9H-purin-6-ylamine for use according to the present disclosure wherein the composition comprises 15-45 mg 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6- ylamine.

[0075] The disclosure may provide a composition comprising 2-butyl-9-methyl-8-(2H-l,2,3- triazol-2-yl)-9H-purin-6-ylamine for use according to the previous aspect wherein the composition further comprises one or more pharmaceutically acceptable excipients.

[0076] Pharmaceutically acceptable excipients may include but are not limited to: carriers, diluents, fillers, disintegrants, lubricating agents, binders, colorants, pigments, stabilizers, preservatives, antioxidants, and / or solubility enhancers.

[0077] Compositions comprising 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine can be formulated by techniques known in the art, such as the techniques published in Remington's Pharmaceutical Sciences, 20th Edition. The pharmaceutical compositions can be formulated as dosage forms for oral, parenteral, such as intramuscular, intravenous, subcutaneous, intradermal, intraarterial, intracardial, rectal, nasal, topical, aerosol or vaginal administration. The pharmaceutical composition may be formulated as a dosage form for oral administration.

[0078] Dosage forms for oral administration include coated and uncoated tablets, soft gelatin capsules, hard gelatin capsules, lozenges, troches, solutions, emulsions, suspensions, syrups, elixirs, powders and granules for reconstitution, dispersible powders and granules, medicated gums, chewing tablets and effervescent tablets. Dosage forms for parenteral administration include solutions, emulsions, suspensions, dispersions and powders and granules for reconstitution. Emulsions are a preferred dosage form for parenteral administration. Dosage forms for rectal and vaginal administration include suppositories and ovula. Dosage forms for nasal administration can be administered via inhalation and insufflation, for example by a metered inhaler. Dosage forms for topical administration include creams, gels, ointments, salves, patches and transdermal delivery systems.

[0079] If the composition comprising 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6- ylamine is administered parenterally, then examples of such administration include one or more of: intravenously, intraarterially, intraperitoneally, intrathecally, intraventricularly, intraurethrally, intrasternally, intracardially, intracranially, intramuscularly or subcutaneously, and / or by using infusion techniques. For parenteral administration, the compounds are best used in the form of a sterile aqueous solution which may contain other substances, for example, enough salts or glucose to make the solution isotonic with blood. The aqueous solutions should be suitably buffered (preferably to a pH of from 3 to 9), if necessary. The preparation of suitable parenteral formulations under sterile conditions is readily accomplished by standard pharmaceutical techniques well known in the art.

[0080] The composition comprising 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6- ylamine can also be administered orally in the form of tablets, capsules, ovules, elixirs, solutions or suspensions, which may contain flavouring or colouring agents, for immediate-, modified-, pulsed- or controlled-release applications.

[0081] The tablets may contain excipients such as microcrystalline cellulose, lactose, sodium citrate, calcium carbonate, dibasic calcium phosphate and glycine, disintegrants such as starch (preferably corn, potato or tapioca starch), sodium starch glycolate, croscarmellose sodium and certain complex silicates, and granulation binders such as polyvinylpyrrolidone, hydroxypropylmethylcellulose (HPMC), hydroxypropylcellulose (HPC), sucrose, gelatin and acacia. Additionally, lubricating agents such as magnesium stearate, stearic acid, glyceryl behenate and talc may be included. Solid compositions of a similar type may also be employed as fillers in gelatin capsules. Preferred excipients in this regard include lactose, starch, a cellulose, or high molecular weight polyethylene glycols. For aqueous suspensions and / or elixirs, the agent may be combined with various sweetening or flavouring agents, colouring matter or dyes, with emulsifying and / or suspending agents and with diluents such as water, ethanol, propylene glycol and glycerin, and combinations thereof.

[0082] Alternatively, composition comprising 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H- purin-6-ylamine can be administered in the form of a suppository or pessary, or may be applied topically in the form of a gel, hydrogel, lotion, solution, cream, ointment or dusting powder. It may also be dermally or transdermally administered, for example, by the use of a skin patch.

[0083] The composition comprising 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6- ylamine may also be administered by the pulmonary route, rectal routes, or the ocular route. For ophthalmic use, they can be formulated as micronized suspensions in isotonic, pH adjusted, sterile saline, or, preferably, as solutions in isotonic, pH adjusted, sterile saline, optionally in combination with a preservative such as a benzalkonium chloride. Alternatively, they may be formulated in an ointment such as petrolatum. It is also envisaged to prepare dry powder formulations of the composition comprising

[0084] 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine for pulmonary administration, particularly inhalation. Such dry powders may be prepared by spray drying under conditions which result in a substantially amorphous glassy or a substantially crystalline bioactive powder. Accordingly, dry powders of the EGFR inhibitors / antagonists can be made according to the emulsification / spray drying process disclosed in WO 99 / 16419 or WOOl / 85136. Spray drying of solution formulations of the compounds of the present disclosure is carried out, for example, as described generally in the "Spray Drying Handbook", 5th ed., K. Masters, John Wiley & Sons, Inc., NY, NY (1991), and in WO 97 / 41833 or WO 03 / 053411.

[0085] For topical application to the skin, the composition comprising 2-butyl-9-methyl-8-(2H- l,2,3-triazol-2-yl)-9H-purin-6-ylamine can be formulated as a suitable ointment containing the active compound suspended or dissolved in, for example, a mixture with one or more of the following: mineral oil, liquid petrolatum, white petrolatum, propylene glycol, emulsifying wax and water. Alternatively, they can be formulated as a suitable lotion or cream, suspended or dissolved in, for example, a mixture of one or more of the following: mineral oil, sorbitan monostearate, a polyethylene glycol, liquid paraffin, polysorbate 60, cetyl esters wax, 2-octyldodecanol, benzyl alcohol and water.

[0086] The composition comprising 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6- ylamine may also be administered by the intranasal route. Advantages of the intranasal route include:

[0087] -unlike parenteral administration, the intranasal administration is not invasive, is generally well tolerated and is easy to self-manage;

[0088] -unlike what happens after oral administration, the substance administered does not have to pass through the digestive system of the gastrointestinal tract or undergo hepatic metabolization; -the available area of nasal mucosa for absorption is relatively large and easily accessible;

[0089] - and given that dwell time of the substance in the nose is short, the haematic concentration peak is quickly reached and this can be time by time controlled.

[0090] The disclosure may provide a composition comprising 2-butyl-9-methyl-8-(2H-l,2,3- triazol-2-yl)-9H-purin-6-ylamine for use according to the previous aspect wherein the composition is formulated as a solid dose.

[0091] The disclosure may provide a composition comprising 2-butyl-9-methyl-8-(2H-l,2,3- triazol-2-yl)-9H-purin-6-ylamine for use according to the previous aspect wherein the composition is formulated for oral delivery.

[0092] In a third aspect the disclosure provides a composition comprising between 5-60 mg 2- butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine.

[0093] The disclosure may provide a composition comprising 2-butyl-9-methyl-8-(2H-l,2,3- triazol-2-yl)-9H-purin-6-ylamine wherein the composition comprises any of 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39 or 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 or 60 mg 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine.

[0094] The disclosure may provide a composition comprising 2-butyl-9-methyl-8-(2H-l,2,3- triazol-2-yl)-9H-purin-6-ylamine wherein the composition comprises 15-45 mg 2-butyl- 9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine.

[0095] The disclosure may provide a composition comprising 2-butyl-9-methyl-8-(2H-l,2,3- triazol-2-yl)-9H-purin-6-ylamine wherein the composition comprises any of 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39 or 40, 41, 42, 43, 44 or 45 mg 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine. The disclosure may provide a composition comprising 2-butyl-9-methyl-8-(2H-l,2,3- triazol-2-yl)-9H-purin-6-ylamine wherein the composition further comprises one or more pharmaceutically acceptable excipients.

[0096] The disclosure may provide a composition comprising 2-butyl-9-methyl-8-(2H-l,2,3- triazol-2-yl)-9H-purin-6-ylamine wherein the composition is formulated as a solid dose

[0097] The disclosure may provide a composition comprising 2-butyl-9-methyl-8-(2H-l,2,3- triazol-2-yl)-9H-purin-6-ylamine wherein the composition is formulated for oral delivery.

[0098] Any reference herein to 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine includes all pharmaceutically acceptable salt forms thereof. This includes salt forms which may be formed, e.g., by protonation of an atom carrying an electron lone pair which is susceptible to protonation, such as an amino group, with an inorganic or organic acid, or as a salt of a carboxylic acid group with a physiologically acceptable cation as they are well-known in the art.

[0099] In terms of general pharmacology, exemplary base addition salts comprise, for example: alkali metal salts such as sodium or potassium salts; alkaline earth metal salts such as calcium or magnesium salts; zinc salts; ammonium salts; aliphatic amine salts such as trimethylamine, triethylamine, cyclohexylamine, ethanolamine, diethanolamine, triethanolamine, procaine salts, meglumine salts, ethylenediamine salts, or choline salts; aralkyl amine salts such as N,N-dibenzylethylenediamine salts, benzathine salts, benethamine salts; heterocyclic aromatic amine salts such as pyridine salts, picoline salts, quinoline salts or isoquinoline salts; quaternary ammonium salts such as tetramethylammonium salts, tetraethylammonium salts, benzyltrimethylammonium salts, benzyltriethylammonium salts, benzyltributylammonium salts, methyltrioctylammonium salts or tetrabutylammonium salts; and basic amino acid salts such as arginine salts, lysine salts, or histidine salts. Exemplary acid addition salts comprise, for example: mineral acid salts such as hydrochloride, hydrobromide, hydroiodide, sulfate salts, nitrate salts, phosphate salts (such as, e.g., phosphate, hydrogenphosphate, or dihydrogenphosphate salts), carbonate salts, hydrogencarbonate salts or perchlorate salts; organic acid salts such as acetate, propionate, butyrate, pentanoate, hexanoate, heptanoate, octanoate, cyclopentanepropionate, decanoate, undecanoate, oleate, stearate, lactate, maleate, oxalate, fumarate, tartrate, malate, citrate, succinate, glycolate, nicotinate, benzoate, salicylate, ascorbate, or pamoate (embonate) salts; sulfonate salts such as methanesulfonate (mesylate), ethanesulfonate (esylate), 2-hydroxyethanesulfonate (isethionate), benzenesulfonate (besylate), p-toluenesulfonate (tosylate), 2- naphthalenesulfonate (napsylate), 3-phenylsulfonate, or camphorsulfonate salts; and acidic amino acid salts such as aspartate or glutamate salts.

[0100] It will be understood that any reference to the use of or composition comprising 2-butyl- 9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine may also refer to the use or a composition comprising an active metabolite of 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2- yl)-9H-purin-6-ylamine or mixture of active metabolites thereof.

[0101] The present disclosure relates to a method of treating a human to entrain their circadian rhythm comprising the administration of 5-60mg of 2-butyl-9-methyl-8-(2H-l,2,3- triazol-2-yl)-9H-purin-6-ylamine. The administration and / or dosage may be as described herein.

[0102] The human may be a human subject in need of treatment.

[0103] The human may have a circadian rhythm disease or disorder which means their circadian rhythm requires entraining. Various physiological or environmental conditions in which the human's circadian rhythm nay need entrainment are described herein, including lack of ability to sense light, shift work and trans-meridian travel. The human may have an alternative condition that requires their circadian rhythm entrained, such that the treatment for the condition may be more efficacious. Suitable conditions are described herein, but includes any one of cancer, MDD, SAD, Parkinson's, major psychoses and Schizophrenia.

[0104] The method of treatment described herein is administered such that the blood concentration of 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine and / or it's active metabolites thereof reach between 1 and 100 ng / mL within about 90 minutes of administration of the oral dose.

[0105] The disclosure further relates to:

[0106] 1. 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine for use in the entrainment of circadian rhythm in a human subject in need thereof wherein 2-butyl-9- methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine is delivered in a dose of 5-60 mg.

[0107] 2. 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine for use according to paragraph 1 wherein the total blood concentration of 2-butyl-9-methyl-8-(2H-l,2,3- triazol-2-yl)-9H-purin-6-ylamine and / or its active metabolites reaches between 1 and 100 ng / ml.

[0108] 3. 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine for use according to paragraphs 1 or 2 wherein the subject in need thereof has a free-running or nonentrained circadian rhythm.

[0109] 4. 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine for use according to any of paragraphs 1 to 3 wherein the subject has no ability to sense light.

[0110] 5. 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine for use according to paragraph 4 wherein the subject is anopthalmic. 6. 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine for use according to paragraphs 1 or 2 wherein the subject is in an environment where there is insufficient light to entrain circadian rhythm to a 24h cycle.

[0111] 7. 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine for use according to paragraphs 1 or 2 wherein the subject is sighted and requires re-entrainment of their circadian rhythm to a new circadian rhythm.

[0112] 8. 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine for use according to paragraph 7 wherein the subject is a shift worker.

[0113] 9. 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine for use according to paragraph 7 wherein the subject has jet-lag disorder or is preparing for trans-meridian travel.

[0114] 10. 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine for use according to paragraph 7 wherein the subject is a patient receiving an additional treatment and wherein the additional treatment benefits from delivery at a particular point in the subject's circadian rhythm.

[0115] 11. 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine for use according to paragraph 10 wherein the patient has cancer and the additional treatment is chemotherapy.

[0116] 12. 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine for use according to paragraph 10 wherein the patient has Parkinson's disease and the additional treatment is an approved treatment for Parkinson's disease. 13. 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine for use according to paragraphs 1 or 2 wherein the subject has Major Depressive Disorder or Seasonal

[0117] Affective Disorder.

[0118] 14. 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine for use according to claim 1 or claim 2 wherein the subject has Major Psychoses or Schizophrenia.

[0119] 15. A composition comprising 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6- ylamine for use according to any one of paragraphs 1 to 14 wherein the composition comprises any of 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39 or 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 or 60 mg 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2- yl)-9H-purin-6-ylamine.

[0120] 16. The composition comprising 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin- 6-ylamine for use according to paragraph 15 wherein the composition comprises 15-45 mg 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine.

[0121] 17. The composition comprising 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin- 6-ylamine for use according to paragraphs 15 or 16 wherein the composition further comprises one or more pharmaceutically acceptable excipients.

[0122] 18. The composition comprising 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin- 6-ylamine for use according to any of paragraphs 15 to 17 wherein the composition is formulated as a solid dose.

[0123] 19. A composition comprising 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6- ylamine for use according to any of paragraphs 15 to 18 wherein the composition is formulated for oral delivery. 20. A composition comprising between 5-60 mg 2-butyl-9-methyl-8-(2H-l,2,3- triazol-2-yl)-9H-purin-6-ylamine.

[0124] 21. The composition comprising 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin- 6-ylamine according to paragraph 20 wherein the composition comprises any of 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, T1 , 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39 or 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 or 60 mg 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6- ylamine.

[0125] 22. The composition comprising 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin- 6-ylamine according to paragraph 21 wherein the composition comprises 15-45 mg 2- butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine.

[0126] 23. The composition comprising 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin- 6-ylamine according to paragraph 22 wherein the composition comprises any of 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, T1 , 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39 or 40, 41, 42, 43, 44 or 45 mg 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6- ylamine.

[0127] 24. A composition comprising 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6- ylamine according to any of paragraphs 20 to 23 wherein the composition further comprises one or more pharmaceutically acceptable excipients.

[0128] 25. A composition comprising 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6- ylamine according to any of paragraphs 20 to 24 wherein the composition is formulated as a solid dose. 26. A composition comprising 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6- ylamine according to any of paragraphs 20 to 25 wherein the composition is formulated for oral delivery.

[0129] The invention will be further described, by means of non-limiting example only, with reference to the following experimental examples.

[0130] Example 1 - Measurement of plasma mean Cmax values for CT1500, CT1517 and CT1518 for humans

[0131] A clinical study was conducted to determine the pharmacokinetics of CT1500 and to investigate the production of CT1517 and CT1518 from CT1500

[0132] Subjects (males or females) were between 18 to 60 years at the time of screening, generally healthy with the exception of those medical conditions allowed per the inclusion / exclusion criteria, had a body mass index of 18.5 to 32 kg / m2and weight greater than or equal to 48 kg at the time of screening and Day -1.

[0133] Women of childbearing potential (WOCBP) were required to have a negative serum pregnancy test at screening and a negative urine pregnancy test at Day -1 and could not be breastfeeding, lactating or planning pregnancy during the study period. WOCBP agreed to use 2 acceptable forms of contraception during the study and for at least 32 days after the last dose of investigational product.

[0134] A male subject with a female partner of childbearing potential was eligible to participate if he agreed to use acceptable contraception during the treatment period and for at least 92 days after the last dose of investigational product and refrained from donating sperm during this period.

[0135] Subjects were randomly assigned with a ratio of 3:1 to receive either CT1500 or matching placebo respectively as an oral dose. The study consisted of a screening period, treatment period and follow-up period. Subjects undertook a screening visit between Day -28 and Day -2 to determine eligibility in the study. Those subjects that met the eligibility criteria were admitted to the study site on the day prior to dosing (Day -1) where continued eligibility was assessed. On Day

[0136] 1 prior to dosing, baseline assessments were performed. Subjects were then dosed according to the randomization schedule.

[0137] All 46 subjects who received CT1500 were included in the analysis. Blood samples for the determination of plasma concentrations of CT1500 and its metabolites (CT1517 and CT1518) were collected from subjects pre-dose, regularly over 12 hours post-dose and 24 hours post-dose. Plasma concentrations of CT1500 and its metabolites (CT1517 and CT1518) were determined using validated liquid chromatography-mass spectrometry assays following extraction of the plasma sample.

[0138] Table 1 - Plasma mean Cmax values for CT analytes Table 2 Peak plasma concentration of analytes after single 60mg and 120mg oral doses CT1500

[0139] This data demonstrates the non-linear pharmacokinetics of CT1500 administration. For doses of 60 mg and below CT1500 is rapidly metabolised to CT1517 and CT1518. On the other hand a dose of 120 mg leads to orders of magnitude higher concentrations of CT1500, and significantly higher concentrations of CT1517 and CT1518 versus a 60 mg dose.

[0140] Table 3 - Duration of time that analyte exposure exceeded adenosine receptor Ki following a single dose of CT1500

[0141] Doses of 60 mg and below produce exposure times of less than 5h which are suitable for entraining circadian rhythm. A dose of 120 mg leads to exposure for over lOh for some analytes which is comparable to caffeine and will not entrain circadian rhythm.

[0142] Example 2 - Comparative mouse data

[0143] All studies were conducted on animals over 50 days of age. Animals were group housed with food and water ad libitum under a 12:12 h light :da rk (LD) cycle. All procedures were performed in accordance with the UK Home Office Animals (Scientific Procedures) Act 1986 and the University of Oxford's Policy on the Use of Animals in Scientific Research (PPL 8092CED3). Animals were sacrificed via Schedule 1 methods in accordance with the UK Home Office Animals (Scientific Procedures) Act 1986 and approved by the University of Oxford Committee on Animal Care and Ethical Review (ACER).

[0144] Oral gavage: The drugs were formulated as a suspension in 10% sucrose (w / v) and 0.3% Tween 80 (v / v) in water. A weighed quantity of drug was added to an Eppendorf tube and wetted with a small quantity of vehicle and initially made into a smooth paste using a pestle. The paste was then made up to final quantity with vehicle and homogenised in an ultrasonic bath in short bursts for up to 32 min until visibly homogeneous. Formulations were dispensed into amber glass bottles for dosing and stored refrigerated (2°C-8°C). Formulations were stirred for at least 15 min before the start of dosing until the completion of their use for dosing, to ensure thorough re-suspension and homogeneity. When the time point of administration was in the dark, the procedure was conducted under dim red light.

[0145] Plasma concentrations of CT1500 and its metabolites (CT1517 and CT1518) were determined using validated liquid chromatography-mass spectrometry assays following extraction of plasma samples after serial blood collections from treated animals.

[0146] Table 4 - Mouse PO dosing plasma mean Cmax values for CT analytes. * Human

[0147] Equivalent Dose, From Nair and Jacob (2016), BLQ = below level of quantification. It is clear from this data that doses equivalent to 30 mg in humans elicit far higher concentrations of CT analytes in mouse plasma. Notably whereas this dose in humans leads to almost complete rapid metabolism of CT1500, plasma concentrations of CT1500 are high (>180 nM) in mice indicating a different rate of metabolism. Another difference is that whilst in humans roughly equivalent quantities of CT1517 and CT1518 are produced, whereas mice exhibit a clear predominance for metabolism to CT1518.

Claims

Claims1. 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine for use in the entrainment of circadian rhythm in a human subject in need thereof wherein 2- butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine is delivered in a dose of 5 to 60 mg.

2. 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine for use according to claim 1, wherein the dose of 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H- purin-6-ylamine provides a length of time the plasma concentration of 2-butyl- 9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine exceeds the Ki for Ai and AZA receptors of 5 hours or less.

3. 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine for use according to claim 1, wherein the dose of 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H- purin-6-ylamine provides a the length of time the plasma concentration of 2- butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine, and / or the plasma concentration of CT1517, and / or the plasma concentration of CT1518, exceeds the Ki for Ai and AZA receptors of 5 hours or less.

4. 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine for use according to any one of claims 1 to 3, wherein the dose of 2-butyl-9-methyl-8-(2H-l,2,3- triazol-2-yl)-9H-purin-6-ylamine elicits entrainment of circadian rhythm for a maximum period of up to 5 hours.

5. 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine for use according to any one of claims 1 to 4, wherein butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H- purin-6-ylamine is delivered in a dose of 5 to 45 mg, such as 5 to 30 mg.

6. 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine for use according to any one of claims 1 to 5, wherein the total blood concentration of 2-butyl-9- methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine and / or its active metabolites reaches between 1 and 100 ng / ml.

7. 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine for use according to anyone of claims Ito 6, wherein the human subject in need thereof is selected from the group comprising: a. a subject having a free-running or non-entrained circadian rhythm; b. a subject having no ability to sense light, such as a subject that is anopthalmic; c. a subject that is in an environment where there is insufficient light to entrain circadian rhythm to a 24h cycle; d. a subject that is sighted and requires re-entrainment of their circadian rhythm to a new circadian rhythm; e. a subject that is a shift worker, and the subject is sighted and requires reentrainment of their circadian rhythm to a new circadian rhythm; f. a subject that has jet-lag disorder or is preparing for trans-meridian travel, and the subject is sighted and requires re-entrainment of their circadian rhythm to a new circadian rhythm; g. a subject that is sighted and requires re-entrainment of their circadian rhythm to a new circadian rhythm and the subject is a patient receiving an additional treatment and wherein the additional treatment benefits from delivery at a particular point in the subject's circadian rhythm; h. a subject that is sighted and requires re-entrainment of their circadian rhythm to a new circadian rhythm and the subject is a patient that has cancer and is receiving additional chemotherapy treatment, and wherein the additional chemotherapy treatment benefits from delivery at a particular point in the subject's circadian rhythm; ori. a subject that is sighted and requires re-entrainment of their circadian rhythm to a new circadian rhythm and the subject is a patient that has Parkinson's disease and is receiving additional approved treatment for Parkinson's disease, and wherein the additional approved treatment for Parkinson's disease benefits from delivery at a particular point in the subject's circadian rhythm.

8. 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine for use according to any one of claims 1 to 6, wherein the human subject has a Major Depressive Disorder, a Seasonal Affective Disorder, Major Psychoses, or Schizophrenia.

9. A pharmaceutical composition comprising 2-butyl-9-methyl-8-(2H-l,2,3-triazol- 2-yl)-9H-purin-6-ylamine, wherein the composition comprises 5 to 60 mg, such as 5 to 45 mg, such as 5 to 30 mg, 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H- purin-6-ylamine.

10. A pharmaceutical composition as claimed in claim 9, wherein the pharmaceutical composition is for use in the entrainment of circadian rhythm in a human subject in need thereof, as defined in any one of the preceding claims.

11. A pharmaceutical composition as claimed in claim 9 or 10, wherein the composition further comprises one or more pharmaceutically acceptable excipients.

12. A pharmaceutical composition as claimed in any one of claims 9 to 11, wherein the composition is formulated as a solid dosage form.

13. A pharmaceutical composition as claimed in any one of claims 9 to 12, wherein the composition is formulated for oral delivery.

14. A pharmaceutical composition as claimed in anyone of claims 9 to 13, wherein the composition comprises any of 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39 or 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 or 60 mg 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine.

15. A pharmaceutical composition as claimed in any one of claims 9 to 14, wherein the composition comprises 15 to 45 mg 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2- yl)-9H-purin-6-ylamine.

16. Use of 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6-ylamine in the manufacture of a medicament for treating a human subject, as defined in any one of the preceding claims, to entrain their circadian rhythm, as defined in any one of the preceding claims, wherein the medicament comprises 5 to 60 mg, such as 5 to 45 mg, such as 5 to 30 mg, 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2- yl)-9H-purin-6-ylamine.

17. A method of treating a human subject, as defined in any one of the preceding claims, to entrain their circadian rhythm, as defined in any one of the preceding claims, the method comprising administering 5 to 60 mg, such as 5 to 45 mg, such as 5 to 30 mg, 2-butyl-9-methyl-8-(2H-l,2,3-triazol-2-yl)-9H-purin-6- ylamine to the human subject.

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