POLYMORPHS OF N-[(2,6-DIFLUORO-3-METHOXYPHENYL)METHYL]-3-(METHOXYMETHYL)-l -({4-[(2- OXOPYRIDIN-l-YL)M ETHYL] PHENYL}M ETHYL)PYRAZOLE-4-CARBOXAM IDE

The present invention relates to new polymorphs of a plasma kallikrein inhibitor, a pharmaceutical composition containing them and their use in therapy.

Background to the Invention

Inhibitors of plasma kallikrein have a number of therapeutic applications, particularly in the treatment of retinal vascular permeability associated with diabetic retinopathy, diabetic macular edema and hereditary angioedema.

Plasma kallikrein is a trypsin-like serine protease that can liberate kinins from kininogens (see K. D. Bhoola et al., "Kallikrein-Kinin Cascade", Encyclopeclia of Respiratory Medicine, p483-493; J. W. Bryant et al., "Human plasma kallikrein-kinin system: physiological and biochemical parameters" Cardiovascular and haematological agents in medicinal chemistry, 7, p234-250, 2009; K. D. Bhoola et al.,

Pharmacological Rev., 1992, 44, 1; and D. J. Campbell, "Towards understanding the kallikrein-kinin system: insights from the measurement of kinin peptides", Brazilian Journal of Medical and Biological Research 2000, 33, 665-677). It is an essential member of the intrinsic blood coagulation cascade although its role in this cascade does not involve the release of bradykinin or enzymatic cleavage.

Plasma prekallikrein is encoded by a single gene and synthesized in the liver. It is secreted by hepatocytes as an inactive plasma prekallikrein that circulates in plasma as a heterodimer complex bound to high molecular weight kininogen which is activated to give the active plasma kallikrein. Kinins are potent mediators of inflammation that act through G protein-coupled receptors and antagonists of kinins (such as bradykinin antagonists) have previously been investigated as potential therapeutic agents for the treatment of a number of disorders (F. Marceau and D. Regoli, Nature Rev., Drug Discovery, 2004, 3, 845-852).

Plasma kallikrein is thought to play a role in a number of inflammatory disorders. The major inhibitor of plasma kallikrein is the serpin CI esterase inhibitor. Patients who present with a genetic deficiency in CI esterase inhibitor suffer from hereditary angioedema (HAE) which results in intermittent swelling of face, hands, throat, gastro-intestinal tract and genitals. Blisters formed during acute episodes contain high levels of plasma kallikrein which cleaves high molecular weight kininogen liberating bradykinin leading to increased vascular permeability. Treatment with a large protein plasma kallikrein inhibitor has been shown to effectively treat HAE by preventing the release of bradykinin which causes increased vascular permeability (A. Lehmann "Ecallantide (DX-88), a plasma kallikrein inhibitor for the treatment of hereditary angioedema and the prevention of blood loss in on-pump cardiothoracic surgery" Expert Opin. Biol. Ther. 8, pll87-99).

The plasma kallikrein-kinin system is abnormally abundant in patients with advanced diabetic macular edema. It has been recently published that plasma kallikrein contributes to retinal vascular dysfunctions in diabetic rats (A. Clermont et al. "Plasma kallikrein mediates retinal vascular dysfunction and induces retinal thickening in diabetic rats" Diabetes, 2011, 60, pl590-98). Furthermore, administration of the plasma kallikrein inhibitor ASP-440 ameliorated both retinal vascular permeability and retinal blood flow abnormalities in diabetic rats. Therefore a plasma kallikrein inhibitor should have utility as a treatment to reduce retinal vascular permeability associated with diabetic retinopathy and diabetic macular edema.

Plasma kallikrein also plays a role in blood coagulation. The intrinsic coagulation cascade may be activated by factor XII (FXII). Once FXII is activated (to FXIIa), FXIIa triggers fibrin formation through the activation of factor XI (FXI) thus resulting in blood coagulation. Plasma kallikrein is a key component in the intrinsic coagulation cascade because it activates FXII to FXIIa, thus resulting in the activation of the intrinsic coagulation pathway. Furthermore, FXIIa also activates further plasma prekallikrein resulting in plasma kallikrein. This results in positive feedback amplification of the plasma kallikrein system and the intrinsic coagulation pathway (Tanaka et al. (Thrombosis Research 2004, 113, 333-339); Bird et al.

(Thrombosis and Haemostasis, 2012, 107, 1141-50).

Contact of FXII in the blood with negatively charged surfaces (such as the surfaces of external pipes or the membrane of the oxygenator that the blood passes during cardiopulmonary bypass surgery) induces a conformational change in zymogen FXII resulting in a small amount of active FXII (FXIIa). The formation of FXIIa triggers the formation of plasma kallikrein resulting in blood coagulation, as described above. Activation of FXII to FXIIa can also occur in the body by contact with negatively charged surfaces on various sources (e.g. bacteria during sepsis, NA from degrading cells), thus resulting in disseminated intravascular coagulation (Tanaka et al. (Thrombosis Research 2004, 113, 333-339)). Therefore, inhibition of plasma kallikrein would inhibit the blood coagulation cascade described above, and so would be useful in the treatment of disseminated intravascular coagulation and blood coagulation during cardiopulmonary bypass surgery where blood coagulation is not desired. For example, Katsuura et al. (Thrombosis Research, 1996, 82, 361-368) showed that administration of a plasma kallikrein inhibitor, PKSI-527, for LPS-induced disseminated intravascular coagulation significantly suppressed the decrease in platelet count and fibrinogen level as well as the increase in FDP level which usually occur in disseminated intravascular coagulation. Bird et al. (Thrombosis and

Haemostasis, 2012, 107, 1141-50) showed that clotting time increased, and thrombosis was significantly reduced in plasma kallikrein-deficient mice. evenko et al. (Blood, 2011, 118, 5302-5311) showed that the reduction of plasma prekallikrein levels in mice using antisense oligonucleotide treatment resulted in antithrombotic effects. Tanaka et al. (Thrombosis Research 2004, 113, 333-339) showed that contacting blood with DX-88 (a plasma kallikrein inhibitor) resulted in an increase in activated clotting time (ACT). Lehmann et al. (Expert Opin. Biol. Ther. 2008, 1187-99) showed that Ecallantide (a plasma kallikrein inhibitor) was found to delay contact activated induced coagulation. Lehmann et al. conclude that Ecallantide "had in vitro anticoagulant effects as it inhibited the intrinsic pathway of coagulation by inhibiting plasma kallikrein".

Plasma kallikrein also plays a role in the inhibition of platelet activation, and therefore the cessation of bleeding. Platelet activation is one of the earliest steps in hemostasis, which leads to platelet plug formation and the rapid cessation of bleeding following damage to blood vessels. At the site of vascular injury, the interaction between the exposed collagen and platelets is critical for the retention and activation of platelets, and the subsequent cessation of bleeding.

Once activated, plasma kallikrein binds to collagen and thereby interferes with collagen-mediated activation of platelets mediated by GPVI receptors (Liu et al. (Nat Med., 2011, 17, 206-210)). As discussed above, plasma kallikrein inhibitors reduce plasma prekallikrein activation by inhibiting plasma kallikrein-mediated activation of factor XII and thereby reducing the positive feedback amplification of the kallikrein system by the contact activation system.

Therefore, inhibition of plasma kallikrein reduces the binding of plasma kallikrein to collagen, thus reducing the interference of plasma kallikrein in the cessation of bleeding. Therefore plasma kallikrein inhibitors would be useful in the treatment of treating cerebral haemorrhage and bleeding from post operative surgery. For example, Liu et al. (Nat Med., 2011, 17, 206-210) demonstrated that systemic administration of a small molecule PK inhibitor, ASP-440, reduced hematoma expansion in rats. Cerebral hematoma may occur following intracerebral haemorrhage and is caused by bleeding from blood vessels into the surrounding brain tissue as a result of vascular injury. Bleeding in the cerebral haemorrhage model reported by Liu et al. was induced by surgical intervention involving an incision in the brain parenchyma that damaged blood vessels. These data demonstrate that plasma kallikrein inhibition reduced bleeding and hematoma volume from post operative surgery. Bjorkqvist et al. (Thrombosis and Haemostasis, 2013, 110, 399- 407) demonstrated that aprotinin (a protein that inhibits serine proteases including plasma kallikrein) may be used to decrease postoperative bleeding. Other complications of diabetes such as cerebral haemorrhage, nephropathy, cardiomyopathy and neuropathy, all of which have associations with plasma kallikrein may also be considered as targets for a plasma kallikrein inhibitor.

Synthetic and small molecule plasma kallikrein inhibitors have been described previously, for example by Garrett et al. ("Peptide aldehyde...." J. Peptide Res. 52, p62-71 (1998)), T. Griesbacher et al.

("Involvement of tissue kallikrein but not plasma kallikrein in the development of symptoms mediated by endogenous kinins in acute pancreatitis in rats" British Journal of Pharmacology 137, p692-700 (2002)), Evans ("Selective dipeptide inhibitors of kallikrein" WO03/076458), Szelke et al. ("Kininogenase inhibitors" WO92/04371), D. M. Evans et al. (Immunolpharmacology, 32, pll5-116 (1996)), Szelke et al. ("Kininogen inhibitors" WO95/07921), Antonsson et al. ("New peptides derivatives" W094/29335), J. Corte et al. ("Six membered heterocycles useful as serine protease inhibitors" WO2005/123680), J. Sturzbecher et al. (Brazilian J. Med. Biol. Res 27, pl929-34 (1994)), Kettner et al. (US 5,187,157), N. Teno et al. (Chem. Pharm. Bull. 41, pl079-1090 (1993)), W. B. Young et al. ("Small molecule inhibitors of plasma kallikrein" Bioorg. Med. Chem. Letts. 16, p2034-2036 (2006)), Okada et al. ("Development of potent and selective plasmin and plasma kallikrein inhibitors and studies on the structure-activity relationship" Chem. Pharm. Bull. 48, pl964-72 (2000)), Steinmetzer et al. ("Trypsin-like serine protease inhibitors and their preparation and use" WO08/049595), Zhang et al. ("Discovery of highly potent small molecule kallikrein inhibitors" Medicinal Chemistry 2, p545-553 (2006)), Sinha et al. ("Inhibitors of plasma kallikrein" WO08/016883), Shigenaga et al. ("Plasma Kallikrein Inhibitors" WO2011/118672), and Kolte et al. ("Biochemical characterization of a novel high-affinity and specific kallikrein inhibitor", British Journal of Pharmacology (2011), 162(7), 1639-1649). Also, Steinmetzer et al. ("Serine protease inhibitors" WO2012/004678) describes cyclized peptide analogs which are inhibitors of human plasmin and plasma kallikrein.

To date, no small molecule synthetic plasma kallikrein inhibitor has been approved for medical use. Many of the molecules described in the known art suffer from limitations such as poor selectivity over related enzymes such as KLKl, thrombin and other serine proteases, and poor oral availability. The large protein plasma kallikrein inhibitors present risks of anaphylactic reactions, as has been reported for

Ecallantide. Thus there remains a need for compounds that selectively inhibit plasma kallikrein, that do not induce anaphylaxis and that are orally available. Furthermore, the vast majority of molecules in the known art feature a highly polar and ionisable guanidine or amidine functionality. It is well known that such functionalities may be limiting to gut permeability and therefore to oral availability. For example, it has been reported by Jamie J. Chilcote and Sukanto Sinha ("ASP-634: An Oral Drug Candidate for Diabetic MacularEdema", A VO 2012 May 6 ^th - May 9 ^th , 2012, Fort Lauderdale, Florida, Presentation 2240) that ASP-440, a benzamidine, suffers from poor oral availability. It is further reported that absorption may be improved by creating a prodrug such as ASP-634. However, it is well known that prodrugs can suffer from several drawbacks, for example, poor chemical stability and potential toxicity from the inert carrier or from unexpected metabolites. In another report, indole amides are claimed as compounds that might overcome problems associated with drugs possessing poor or inadequate ADME- tox and physicochemical properties although no inhibition against plasma kallikrein is presented or claimed (Griffioen et al, "Indole amide derivatives and related compounds for use in the treatment of neurodegenerative diseases", WO2010, 142801).

BioCryst Pharmaceuticals Inc. have reported the discovery of the orally available plasma kallikrein inhibitor BCX4161 ("BCX4161, An Oral Kallikrein Inhibitor: Safety and Pharmacokinetic Results Of a Phase 1 Study In Healthy Volunteers", Journal of Allergy and Clinical Immunology, Volume 133, Issue 2, Supplement, February 2014, page AB39 and "A Simple, Sensitive and Selective Fluorogenic Assay to Monitor Plasma Kallikrein Inhibitory Activity of BCX4161 in Activated Plasma", Journal of Allergy and Clinical Immunology, Volume 133, Issue 2, Supplement February 2014, page AB40). However, human doses are relatively large, currently being tested in proof of concept studies at doses of 400 mg three times daily. There are only few reports of plasma kallikrein inhibitors that do not feature guanidine or amidine functionalities. One example is Brandl et al. ("N-((6-amino-pyridin-3-yl)methyl)-heteroaryl-carboxamides as inhibitors of plasma kallikrein" WO2012/017020), which describes compounds that feature an amino- pyridine functionality. Oral efficacy in a rat model is demonstrated at relatively high doses of 30 mg/kg and 100 mg/kg but the pharmacokinetic profile is not reported. Thus it is not yet known whether such compounds will provide sufficient oral availability or efficacy for progression to the clinic. Other examples are Brandl et al. ("Aminopyridine derivatives as plasma kallikrein inhibitors" WO2013/111107) and Flohr et al. ("5-membered heteroarylcarboxamide derivatives as plasma kallikrein inhibitors" WO2013/111108). However, neither of these documents report any in vivo data and therefore it is not yet known whether such compounds will provide sufficient oral availability or efficacy for progression to the clinic. Another example is Allan et al. "Benzylamine derivatives" WO2014/108679.

In the manufacture of pharmaceutical formulations, it is important that the active compound be in a form in which it can be conveniently handled and processed in order to obtain a commercially viable manufacturing process. Accordingly, the chemical stability and the physical stability of the active compound are important factors. The active compound, and formulations containing it, must be capable of being effectively stored over appreciable periods of time, without exhibiting any significant change in the physico-chemical characteristics (e.g. chemical composition, density, hygroscopicity and solubility) of the active compound. It is known that manufacturing a particular solid-state form of a pharmaceutical ingredient can affect many aspects of its solid state properties and offer advantages in aspects of solubility, dissolution rate, chemical stability, mechanical properties, technical feasibility, processability, pharmacokinetics and bioavailability. Some of these are described in "Handbook of Pharmaceutical Salts; Properties, Selection and Use", P. Heinrich Stahl, Camille G. Wermuth (Eds.) (Verlag Helvetica Chimica Acta, Zurich). Methods of manufacturing solid-state forms are also described in "Practical Process Research and Development", Neal G. Anderson (Academic Press, San Diego) and "Polymorphism: In the Pharmaceutical Industry", Rolf Hilfiker (Ed) (Wiley VCH). Polymorphism in pharmaceutical crystals is described in Byrn (Byrn, S.R., Pfeiffer, R.R., Stowell, J.G., "Solid-State Chemistry of Drugs", SSCI Inc., West Lafayette, Indiana, 1999), Brittain,H.G., "Polymorphism in Pharmaceutical Solids", Marcel Dekker, Inc., New York, Basel, 1999) or Bernstein (Bernstein, J., "Polymorphism in Molecular Crystals", Oxford University Press, 2002).

The applicant has developed a novel series of compounds that are inhibitors of plasma kallikrein, which are disclosed in WO2016/083820 (PCT/GB2015/053615). These compounds demonstrate good selectivity for plasma kallikrein and are potentially useful in the treatment of diabetic retinopathy, macular edema and hereditary angioedema. One such compound is N-[(2,6-difluoro-3- methoxyphenyl)methyl]-3-(methoxymethyl)-l-({4-[(2-oxopyridin -l-yl)methyl]phenyl}methyl)pyrazole-4- carboxamide. Initial attempts to prepare N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3- (methoxymethyl)-l-({4-[(2-oxopyridin-l-yl)methyl]phenyl}meth yl)pyrazole-4-carboxamide yielded an amorphous solid (Form A). However, the applicant has now developed novel, stable crystalline forms of this compound, which are herein referred to as 'Form 1', 'Form 2' and 'Form 3'. The novel solid forms have advantageous physico-chemical properties that render them suitable for development.

Description of the Invention

Thus, in accordance with an aspect of the present invention, there is provided crystalline polymorphs of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)-l -({4-[(2-oxopyridin-l- yl)methyl]phenyl}methyl)pyrazole-4-carboxamide. In the present application these polymorphs may be referred to as 'Form , 'Form 2' and 'Form 3'. The crystalline polymorphs of the present invention have advantageous physico-chemical properties that render them suitable for development. For example, Gravimetric Vapour Sorption (GVS) data of 'Form of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)-l -({4-[(2-oxopyridin-l- yl)methyl]phenyl}methyl)pyrazole-4-carboxamide, Figure 4, show that hydration is reversible (i.e. no significant hysteresis). Furthermore, these data show that under normal conditions (up to 70% relative humidity) there is only a relatively gradual increase in water content. This is consistent with the absence of significant hygroscopicity. Further evidence of the suitability of the crystalline forms for pharmaceutical development is provided by the stability data disclosed herein. Form 1 of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3- (methoxymethyl)-l-({4-[(2-oxopyridin-l-yl)methyl]phenyl}meth yl)pyrazole-4-carboxamide was stored at 40°C/75% RH in a open glass vial covered with tissue. At the initial timepoint XRPD showed the sample to be crystalline and consistent with the Form 1 polymorph (Figure 1). DSC showed an onset temperature of 154.9 °C (Figure 3). XRPD showed no change after 7 days and after 28 days (Figure 6). Similarly, DSC showed no significant change after 7 days (onset 155.2 °C) and after 28 days (155.0 °C) (Figure 9 and Figure 10).

Yet further evidence of the suitability of the crystalline forms for pharmaceutical development is provided by additional stability data disclosed herein. Form 1 of N-[(2,6-difluoro-3- methoxyphenyl)methyl]-3-(methoxymethyl)-l-({4-[(2-oxopyridin -l-yl)methyl]phenyl}methyl)pyrazole-4- carboxamide was stored separately at two conditions of 40°C/75% RH for 6 months and 25°C/60% RH for 12 months packed into double polyethylene bags inside an HDPE bottle sealed with a screw cap closure. At the initial timepoint XRPD showed the sample to be crystalline and consistent with the Form 1 polymorph. XRPD showed no change after 6 months at 40°C/75% RH, or after 12 months at 25°C/60% RH (Figure 16). All measured parameters including Assay, Water Content, XRPD, DSC, Purity and Impurity Profile remained unchanged over the course of this study.

The name N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)-l -({4-[(2-oxopyridin-l- yl)methyl]phenyl}methyl)pyrazole-4-carboxamide denotes the structure depicted in Figure A.

Figure A

Three crystalline polymorphs of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)-l -({4-[(2- oxopyridin-l-yl)methyl]phenyl}methyl)pyrazole-4-carboxamide have been isolated and characterised to date, which are herein referred to as 'Form , 'Form 2' and 'Form 3'. Preferably, the crystalline form is Form 1.

In the present specification, X-ray powder diffraction peaks (expressed in degrees 2Θ) are measured using Cu Kct radiation.

The present invention provides a crystalline form (Form 1) of N-[(2,6-difluoro-3-methoxyphenyl)methyl]- 3-(methoxymethyl)-l-({4-[(2-oxopyridin-l-yl)methyl]phenyl}me thyl)pyrazole-4-carboxamide, which exhibits at least the following characteristic X-ray powder diffraction peaks (Cu Kct radiation, expressed in degrees 2Θ) at approximately:

(1) 5.5, 9.5, 12.7, 14.7 and 16.7; or

(2) 5.5, 9.5, 12.7, 14.7, 16.7, 18.3 and 20.2; or

(3) 5.5, 9.5, 12.7, 14.7, 15.5, 16.7, 18.3, 19.3 and 20.2. The term "approximately" means in this context that there is an uncertainty in the measurements of the degrees 2Θ of ± 0.3 (expressed in degrees 2Θ), preferably ± 0.2 (expressed in degrees 2Θ).

The present invention also provides a crystalline form (Form 1) of N-[(2,6-difluoro-3- methoxyphenyl)methyl]-3-(methoxymethyl)-l-({4-[(2-oxopyridin -l-yl)methyl]phenyl}methyl)pyrazole-4- carboxamide, having an X ray powder diffraction pattern comprising characteristic peaks (expressed in degrees 2Θ) at approximately 5.5, 9.5, 12.7, 14.7, 15.5, 16.7, 18.3, 19.3, 20.2 and 22.9. Figure 1 shows an X-ray powder diffraction pattern of Form 1 of N-[(2,6-difluoro-3- methoxyphenyl)methyl]-3-(methoxymethyl)-l-({4-[(2-oxopyridin -l-yl)methyl]phenyl}methyl)pyrazole-4- carboxamide. The present invention also provides a crystalline form (Form 1) of N-[(2,6-difluoro-3- methoxyphenyl)methyl]-3-(methoxymethyl)-l-({4-[(2-oxopyridin -l-yl)methyl]phenyl}methyl)pyrazole-4- carboxamide having an X-ray powder diffraction pattern substantially the same as that shown in Figure 1.

The X-ray powder diffraction pattern of a polymorphic form may be described herein as "substantially" the same as that depicted in a Figure. It will be appreciated that the peaks in X-ray powder diffraction patterns may be slightly shifted in their positions and relative intensities due to various factors known to the skilled person. For example, shifts in peak positions or the relative intensities of the peaks of a pattern can occur because of the equipment used, method of sample preparation, preferred packing and orientations, the radiation source, and method and length of data collection. However, the skilled person will be able to compare the X-ray powder diffraction patterns shown in the figures herein with those of an unknown polymorph to confirm the identity of the polymorph.

The present invention also provides a crystalline form (Form 2) of N-[(2,6-difluoro-3- methoxyphenyl)methyl]-3-(methoxymethyl)-l-({4-[(2-oxopyridin -l-yl)methyl]phenyl}methyl)pyrazole-4- carboxamide, which exhibits at least the following characteristic X-ray powder diffraction peaks (Cu Kct radiation, expressed in degrees 2Θ) at approximately:

(1) 9.5, 10.3, 13.2, 15.6 and 16.9; or

(2) 6.5, 9.5, 10.3, 13.2, 14.1, 15.6 and 16.9; or

(3) 6.5, 8.3, 9.5, 10.3, 13.2, 14.1, 15.6, 16.9 and 25.3. The present invention also provides a crystalline form (Form 2) of N-[(2,6-difluoro-3- methoxyphenyl)methyl]-3-(methoxymethyl)-l-({4-[(2-oxopyridin -l-yl)methyl]phenyl}methyl)pyrazole-4- carboxamide, having an X ray powder diffraction pattern comprising characteristic peaks (expressed in degrees 2Θ) at approximately 6.5, 8.3, 9.5, 10.3, 13.2, 14.1, 15.0, 15.6, 16.9, 19.0, 19.2, 21.0, 21.8, 23.5 and 25.3.

Figure 12 shows an X-ray powder diffraction pattern of Form 2 of N-[(2,6-difluoro-3- methoxyphenyl)methyl]-3-(methoxymethyl)-l-({4-[(2-oxopyridin -l-yl)methyl]phenyl}methyl)pyrazole-4- carboxamide. The present invention also provides a crystalline form (Form 2) of N-[(2,6-difluoro-3- methoxyphenyl)methyl]-3-(methoxymethyl)-l-({4-[(2-oxopyridin -l-yl)methyl]phenyl}methyl)pyrazole-4- carboxamide having an X-ray powder diffraction pattern substantially the same as that shown in Figure 12.

The present invention also provides a crystalline form (Form 3) of N-[(2,6-difluoro-3- methoxyphenyl)methyl]-3-(methoxymethyl)-l-({4-[(2-oxopyridin -l-yl)methyl]phenyl}methyl)pyrazole-4- carboxamide, which exhibits at least the following characteristic X-ray powder diffraction peaks (Cu Kct radiation, expressed in degrees 2Θ) at approximately:

(1) 12.3, 13.7, 20.7, 26.2 and 27.8; or

(2) 9.7, 12.3, 13.7, 19.0, 20.7, 26.2 and 27.8; or

(3) 9.7, 12.3, 13.7, 17.7, 19.0, 20.7, 23.2, 26.2 and 27.8.

The present invention also provides a crystalline form (Form 3) of N-[(2,6-difluoro-3- methoxyphenyl)methyl]-3-(methoxymethyl)-l-({4-[(2-oxopyridin -l-yl)methyl]phenyl}methyl)pyrazole-4- carboxamide, having an X ray powder diffraction pattern comprising characteristic peaks (expressed in degrees 2Θ) at approximately 9.7, 12.3, 13.7, 17.7, 19.0, 20.7, 23.2, 26.2 and 27.8.

Figure 13 shows an X-ray powder diffraction pattern of Form 3 of N-[(2,6-difluoro-3- methoxyphenyl)methyl]-3-(methoxymethyl)-l-({4-[(2-oxopyridin -l-yl)methyl]phenyl}methyl)pyrazole-4- carboxamide. The present invention also provides a crystalline form (Form 3) of N-[(2,6-difluoro-3- methoxyphenyl)methyl]-3-(methoxymethyl)-l-({4-[(2-oxopyridin -l-yl)methyl]phenyl}methyl)pyrazole-4- carboxamide having an X-ray powder diffraction pattern substantially the same as that shown in Figure 13.

The skilled person is familiar with techniques for measuring X PD patterns. In particular, the X-ray powder diffraction pattern of the sample of compound may be recorded using a Philips X-Pert MPD diffractometer with the following experimental conditions:

Tube anode: Cu;

Generator tension: 40 kV;

Tube current: 40 mA;

Wavelength alphal: 1.5406 A;

Wavelength alpha2: 1.5444 A;

Sample: 2 mg of sample under analysis gently compressed on the XRPD zero back ground single obliquely cut silica sample holder.

The present invention provides a crystalline form (Form 1) of N-[(2,6-difluoro-3-methoxyphenyl)methyl]- 3-(methoxymethyl)-l-({4-[(2-oxopyridin-l-yl)methyl]phenyl}me thyl)pyrazole-4-carboxamide, which exhibits an endothermic peak in its DSC thermograph at 157 ± 3 °C, preferably 157 ± 2 °C, more preferably 157 ± 1 °C.

The present invention provides a crystalline form (Form 1) of N-[(2,6-difluoro-3-methoxyphenyl)methyl]- 3-(methoxymethyl)-l-({4-[(2-oxopyridin-l-yl)methyl]phenyl}me thyl)pyrazole-4-carboxamide, having a DSC thermograph substantially the same as that shown in Figure 3.

The skilled person is familiar with techniques for measuring DSC thermographs. In particular, the DSC thermograph of the sample of compound may be recorded by

(a) weighing 5 mg of the sample into an aluminium DSC pan and sealing non-hermetically with an aluminium lid;

(b) loading the sample into a Perkin-Elmer Jade DSC and holding the sample at 30°C until a stable heat- flow response is obtained while using a 20 cm ³ /min helium purge;

(c) heating the sample to a temperature of between 200 and 300°C at a scan rate of 10°C/min and monitoring the resulting heat flow response while using a 20 cm ³ /min helium purge.

The present invention provides a crystalline form (Form 1) of N-[(2,6-difluoro-3-methoxyphenyl)methyl]- 3-(methoxymethyl)-l-({4-[(2-oxopyridin-l-yl)methyl]phenyl}me thyl)pyrazole-4-carboxamide having an X-ray powder diffraction pattern as described above, and a DSC thermograph as described above.

A reference to a particular compound also includes all isotopic variants.

The crystalline forms of the present invention can exist in both unsolvated and solvated forms. The term 'solvate' is used herein to describe a molecular complex comprising the compound of the invention and an amount of one or more pharmaceutically acceptable solvents, for example, methanol. The term 'hydrate' is employed when the solvent is water.

In an aspect of the invention, crystalline Form 1 of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3- (methoxymethyl)-l-({4-[(2-oxopyridin-l-yl)methyl]phenyl}meth yl)pyrazole-4-carboxamide is not a solvate or a hydrate.

The present invention also encompasses a process for the preparation of Form 1 of the present invention, said process comprising the crystallisation of said crystalline form from a solution of N-[(2,6- difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)-l-({4-[(2 -oxopyridin-l- yl)methyl]phenyl}methyl)pyrazole-4-carboxamide in a solvent or a mixture of solvents. Preferably, the solvent is isopropanol. After adding the N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)- l-({4-[(2-oxopyridin-l-yl)methyl]phenyl}methyl)pyrazole-4-ca rboxamide to a solvent or a mixture of solvents (e.g. isopropanol), the combined mixture (compound plus solvent(s)) may be heated to a temperature of approximately 60-85°C. Alternatively, the combined mixture may be heated to a temperature of approximately 70-85°C. Alternatively, the combined mixture may be heated to a temperature of approximately 80-85°C. Alternatively, the combined mixture may be heated to a temperature of approximately 80, 81, 82, 83, 84 or 85°C. Alternatively, the combined mixture may be heated to a temperature of approximately 82°C. Alternatively, the combined mixture may be heated to reflux. Following heating, the combined mixture may be cooled. Alternatively, the combined mixture may be cooled to a temperature of approximately 0-40 °C. Alternatively, the combined mixture may be cooled to a temperature of approximately 10-30 °C. Alternatively, the combined mixture may be cooled to room temperature.

The present invention also encompasses a process for the preparation of Form 2 of the present invention, said process comprising the crystallisation of said crystalline form from a solution of N-[(2,6- difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)-l-({4-[(2 -oxopyridin-l- yl)methyl]phenyl}methyl)pyrazole-4-carboxamide in a solvent or a mixture of solvents. Preferably, the solvent is methanol and water. More preferably, the solvent is approximately 50:50 methanol/water. After adding the N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)-l -({4-[(2-oxopyridin-l- yl)methyl]phenyl}methyl)pyrazole-4-carboxamide to a solvent or a mixture of solvents (e.g. methanol and water), the solvent of the combined mixture (compound plus solvent(s)) may be allowed to evaporate.

The present invention also encompasses a process for the preparation of Form 3 of the present invention, said process comprising the crystallisation of said crystalline form from a solution of N-[(2,6- difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)-l-({4-[(2 -oxopyridin-l- yl)methyl]phenyl}methyl)pyrazole-4-carboxamide in a solvent or a mixture of solvents. Preferably, the solvent is methanol and pentane. The crystallisation from methanol and pentane may be performed by adding a solution of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)-l -({4-[(2-oxopyridin- l-yl)methyl]phenyl}methyl)pyrazole-4-carboxamide in methanol to pentane.

The processes of the present invention may also comprise the addition of crystalline seeds of the crystalline form of the invention. In an aspect, the present invention provides the crystalline form of the invention when manufactured by a process according to the invention.

As previously mentioned, the crystalline form of the present invention has a number of therapeutic applications, particularly in the treatment of diseases or conditions mediated by plasma kallikrein.

Accordingly, the present invention provides a crystalline form of N-[(2,6-difluoro-3- methoxyphenyl)methyl]-3-(methoxymethyl)-l-({4-[(2-oxopyridin -l-yl)methyl]phenyl}methyl)pyrazole-4- carboxamide, as hereinbefore defined, for use in therapy. In a preferred embodiment, the crystalline form is Form 1.

The present invention also provides for the use of a crystalline form of N-[(2,6-difluoro-3- methoxyphenyl)methyl]-3-(methoxymethyl)-l-({4-[(2-oxopyridin -l-yl)methyl]phenyl}methyl)pyrazole-4- carboxamide, as hereinbefore defined, in the manufacture of a medicament for the treatment of a disease or condition mediated by plasma kallikrein. In a preferred embodiment, the crystalline form is Form 1.

The present invention also provides a crystalline form of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3- (methoxymethyl)-l-({4-[(2-oxopyridin-l-yl)methyl]phenyl}meth yl)pyrazole-4-carboxamide, as hereinbefore defined, for use in a method of treatment of a disease or condition mediated by plasma kallikrein. In a preferred embodiment, the crystalline form is Form 1.

The present invention also provides a method of treatment of a disease or condition mediated by plasma kallikrein, said method comprising administering to a mammal in need of such treatment a therapeutically effective amount of a crystalline form of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3- (methoxymethyl)-l-({4-[(2-oxopyridin-l-yl)methyl]phenyl}meth yl)pyrazole-4-carboxamide, as hereinbefore defined. In a preferred embodiment, the crystalline form is Form 1.

In an aspect, the disease or condition mediated by plasma kallikrein is selected from impaired visual acuity, diabetic retinopathy, retinal vascular permeability associated with diabetic retinopathy, diabetic macular edema, hereditary angioedema, diabetes, pancreatitus, cerebral haemorrhage, nepropathy, cardiomyopathy, neuropathy, inflammatory bowel disease, arthritis, inflammation, septic shock, hypotension, cancer, adult respiratory distress syndrome, disseminated intravascular coagulation, blood coagulation during cardiopulmonary bypass surgery, and bleeding from post-operative surgery. In a preferred embodiment, the disease or condition mediated by plasma kallikrein is diabetic macular edema. In another preferred embodiment, the disease or condition mediated by plasma kallikrein is hereditary angioedema.

In another aspect, the disease or condition in which plasma kallikrein activity is implicated is retinal vein occlusion.

Alternatively, the disease or condition mediated by plasma kallikrein may be selected from retinal vascular permeability associated with diabetic retinopathy, diabetic macular edema and hereditary angioedema. Alternatively, the disease or condition mediated by plasma kallikrein may be retinal vascular permeability associated with diabetic retinopathy or diabetic macular edema. Alternatively, the disease or condition mediated by plasma kallikrein may be hereditary angioedema. The crystalline form of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)-l -({4-[(2-oxopyridin-l- yl)methyl]phenyl}methyl)pyrazole-4-carboxamide may be administered in a form suitable for injection into the ocular region of a patient, in particular, in a form suitable for intra-vitreal injection.

In the context of the present invention, references herein to "treatment" include references to curative, palliative and prophylactic treatment, unless there are specific indications to the contrary. The terms "therapy", "therapeutic" and "therapeutically" should be construed in the same way. The crystalline form of the present invention may be administered alone or in combination with one or more other drugs. Generally, it will be administered as a formulation in association with one or more pharmaceutically acceptable excipients. The term "excipient" is used herein to describe any ingredient other than the compound(s) of the invention which may impart either a functional (i.e., drug release rate controlling) and/or a non-functional (i.e., processing aid or diluent) characteristic to the formulations. The choice of excipient will to a large extent depend on factors such as the particular mode of administration, the effect of the excipient on solubility and stability, and the nature of the dosage form.

In another aspect, the compounds of the present invention may be administered in combination with laser treatment of the retina. The combination of laser therapy with intravitreal injection of an inhibitor of VEGF for the treatment of diabetic macular edema is known (Elman M, Aiello L, Beck , et al.

"Randomized trial evaluating ranibizumab plus prompt or deferred laser or triamcinolone plus prompt laser for diabetic macular edema" .Ophthalmology. 27 April 2010). Pharmaceutical compositions suitable for the delivery of the crystalline form of the present invention and methods for their preparation will be readily apparent to those skilled in the art. Such compositions and methods for their preparation may be found, for example, in Remington's Pharmaceutical Sciences, 19th Edition (Mack Publishing Company, 1995).

For administration to human patients, the total daily dose of the crystalline form of the invention is typically in the range 0.1 mg and 10000 mg, or between 1 mg and 5000 mg, or between 10 mg and 1000 mg depending, of course, on the mode of administration. If administered by intra-vitreal injection a lower dose of between 0.0001 mg (0.1 μg) and 0.2 mg (200 μg) per eye is envisaged, or between 0.0005 mg (0.5 μg) and 0.05 mg (50 μg) per eye.

The total daily dose may be administered in single or divided doses and may, at the physician's discretion, fall outside of the typical range given herein. These dosages are based on an average human subject having a weight of about 60kg to 70kg. The physician will readily be able to determine doses for subjects whose weight falls outside this range, such as infants and the elderly.

Accordingly, the present invention provides a pharmaceutical composition comprising a crystalline solid form of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)-l -({4-[(2-oxopyridin-l- yl)methyl]phenyl}methyl)pyrazole-4-carboxamide, as hereinbefore defined, and a pharmaceutically acceptable carrier, diluent or excipient. In a preferred embodiment, the crystalline solid form is Form 1.

The pharmaceutical compositions may be administered topically (e.g. to the eye, to the skin or to the lung and/or airways) in the form, e.g., of eye-drops, creams, solutions, suspensions, heptafluoroalkane (HFA) aerosols and dry powder formulations; or systemically, e.g. by oral administration in the form of tablets, capsules, syrups, powders or granules; or by parenteral administration in the form of solutions or suspensions; or by subcutaneous administration; or by rectal administration in the form of suppositories; or transdermally. In a further embodiment, the pharmaceutical composition is in the form of a suspension, tablet, capsule, powder, granule or suppository. In an embodiment of the invention, the active ingredient is administered orally. Oral administration may involve swallowing, so that the compound enters the gastrointestinal tract, and/or buccal, lingual, or sublingual administration by which the compound enters the blood stream directly from the mouth.

Formulations suitable for oral administration include solid plugs, solid microparticulates, semi-solid and liquid (including multiple phases or dispersed systems) such as tablets; soft or hard capsules containing multi- or nano-particulates, liquids, emulsions or powders; lozenges (including liquid-filled); chews; gels; fast dispersing dosage forms; films; ovules; sprays; and buccal/mucoadhesive patches.

Formulations suitable for oral administration may also be designed to deliver the crystalline form in an immediate release manner or in a rate-sustaining manner, wherein the release profile can be delayed, pulsed, controlled, sustained, or delayed and sustained or modified in such a manner which optimises the therapeutic efficacy of the said crystalline form. Means to deliver compounds in a rate-sustaining manner are known in the art and include slow release polymers that can be formulated with the said compounds to control their release.

Liquid (including multiple phases and dispersed systems) formulations include emulsions, suspensions, solutions, syrups and elixirs. Such formulations may be presented as fillers in soft or hard capsules. Liquid formulations may also be prepared by the reconstitution of a solid, for example, from a sachet.

The crystalline form of the invention may also be used in fast-dissolving, fast-disintegrating dosage forms such as those described in Liang and Chen, Expert Opinion in Therapeutic Patents, 2001, 11 (6), 981-986.

The formulation of tablets is discussed in Pharmaceutical Dosage Forms: Tablets, Vol. 1, by H. Lieberman and L. Lachman (Marcel Dekker, New York, 1980).

The invention will now be illustrated by the following non-limiting examples. In the examples the following figures are presented:

Figure 1: X-ray powder diffraction pattern of Form 1 of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-

(methoxymethyl)-l-({4-[(2-oxopyridin-l-yl)methyl]phenyl}m ethyl)pyrazole-4-carboxamide. Figure 2: STA of Form 1 of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)-l -({4-[(2- oxopyridin-l-yl)methyl]phenyl}methyl)pyrazole-4-carboxamide.

Figure 3: DSC thermograph of Form 1 of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-

(methoxymethyl)-l-({4-[(2-oxopyridin-l-yl)methyl]phenyl}m ethyl)pyrazole-4-carboxamide. Figure 4: Gravimetric vapour sorption isotherms (adsorption and desorption) of Form 1 of N-[(2,6- difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)-l-({4-[(2 -oxopyridin-l- yl)methyl]phenyl}methyl)pyrazole-4-carboxamide. Figure 5: X-ray powder diffraction patterns of Form 1 of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3- (methoxymethyl)-l-({4-[(2-oxopyridin-l-yl)methyl]phenyl}meth yl)pyrazole-4-carboxamide before (top) and after (bottom) gravimetric vapour sorption shown in Figure 4.

Figure 6: X-ray powder diffraction patterns of Form 1 of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3- (methoxymethyl)-l-({4-[(2-oxopyridin-l-yl)methyl]phenyl}meth yl)pyrazole-4-carboxamide during a stability study at 0 days (top), 7 days (middle) and 28 days (bottom).

Figure 7: STA of Form 1 of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)-l -({4-[(2- oxopyridin-l-yl)methyl]phenyl}methyl)pyrazole-4-carboxamide after 7 days in a stability study.

Figure 8: STA of Form 1 of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)-l -({4-[(2- oxopyridin-l-yl)methyl]phenyl}methyl)pyrazole-4-carboxamide after 28 days in a stability study.

Figure 9: DSC thermograph of Form 1 of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-

(methoxymethyl)-l-({4-[(2-oxopyridin-l-yl)methyl]phenyl}m ethyl)pyrazole-4-carboxamide after 7 days in the stability study.

Figure 10: DSC thermograph of Form 1 of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-

(methoxymethyl)-l-({4-[(2-oxopyridin-l-yl)methyl]phenyl}m ethyl)pyrazole-4-carboxamide after 28 days in the stability study.

Figure 11: X-ray powder diffraction pattern of Form 1 of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3- (methoxymethyl)-l-({4-[(2-oxopyridin-l-yl)methyl]phenyl}meth yl)pyrazole-4-carboxamide

(recrystallised from isopropanol).

Figure 12: X-ray powder diffraction pattern of Form 2 of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-

(methoxymethyl)-l-({4-[(2-oxopyridin-l-yl)methyl]phenyl}m ethyl)pyrazole-4-carboxamide. Figure 13: X-ray powder diffraction pattern of Form 3 of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3- (methoxymethyl)-l-({4-[(2-oxopyridin-l-yl)methyl]phenyl}meth yl)pyrazole-4-carboxamide. Figure 14: X-ray powder diffraction pattern of Form A of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-

(methoxymethyl)-l-({4-[(2-oxopyridin-l-yl)methyl]phenyl}m ethyl)pyrazole-4-carboxamide. Figure 15: Gravimetric vapour sorption isotherms (adsorption and desorption) of Form A of N-[(2,6- difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)-l-({4-[(2 -oxopyridin-l- yl)methyl]phenyl}methyl)pyrazole-4-carboxamide.

Figure 16: X-ray powder diffraction patterns of Form 1 of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-

(methoxymethyl)-l-({4-[(2-oxopyridin-l-yl)methyl]phenyl}m ethyl)pyrazole-4-carboxamide during a stability study at 0 months (top), 6 months at 40 °C / 75% H (middle) and 12 months at 25 °C / 60%RH (bottom). General Experimental Details

In the following examples, the following abbreviations and definitions

All reactions were carried out under an atmosphere of nitrogen unless specified otherwise. ¹ H NMR spectra were recorded on a Bruker (400MHz) spectrometer with reference to deuterium solvent and at rt. Molecular ions were obtained using LCMS which was carried out using a Chromolith Speedrod RP-18e column, 50 x 4.6 mm, with a linear gradient 10% to 90% 0.1% HC0 ₂ H/MeCN into 0.1% HC0 ₂ H/H ₂ 0 over 13 min, flow rate 1.5 mL/min, or using Agilent, X-Select, acidic, 5-95% MeCN/water over 4 min. Data was collected using a Thermofinnigan Surveyor MSQ mass spectrometer with electospray ionisation in conjunction with a Thermofinnigan Surveyor LC system.

Where products were purified by flash chromatography, 'silica' refers to silica gel for chromatography, 0.035 to 0.070 mm (220 to 440 mesh) (e.g. Merck silica gel 60), and an applied pressure of nitrogen up to 10 p.s.i accelerated column elution. Reverse phase preparative HPLC purifications were carried out using a Waters 2525 binary gradient pumping system at flow rates of typically 20 mL/min using a Waters 2996 photodiode array detector.

All solvents and commercial reagents were used as received.

Chemical names were generated using automated software such as the Autonom software provided as part of the ISIS Draw package from MDL Information Systems or the Chemaxon software provided as a component of MarvinSketch or as a component of the IDBS E-WorkBook.

X-Ray Powder Diffraction patterns were collected, unless stated otherwise, on a Philips X-Pert MPD diffractometer and analysed using the following experimental conditions:

Tube anode: Cu

Generator tension: 40 kV

Tube current: 40 mA

Wavelength alphal: 1.5406 A

Wavelength alpha2: 1.5444 A

Start angle [2Θ]: 4

End angle [2Θ]: 40

Approximately 2 mg of sample under analysis was gently compressed on the XRPD zero back ground single obliquely cut silica sample holder. The sample was then loaded into the diffractometer for analysis. DSC data were collected using the following method: Approximately 5 mg of each sample was weighed into an aluminium DSC pan and sealed non-hermetically with an aluminium lid. The sample was then loaded into a Perkin-Elmer Jade DSC and held at 30°C. Once a stable heat-flow response was obtained, the sample was then heated to a temperature between 200 and 300°C at a scan rate of 10°C/min and the resulting heat flow response was monitored. A 20 cm ³ /min helium purge was used. Prior to analysis, the instrument was temperature and heat flow verified using an indium standard.

Gravimetric Vapour Sorption (GVS) data were collected using the following method: Approximately 10 mg of sample was placed into a wire-mesh vapour sorption balance pan and loaded into an 'IgaSorp' vapour sorption balance (Hiden Analytical Instruments). The sample was then dried by maintaining a 0% humidity environment until no further weight change was recorded. Subsequently, the sample was then subjected to a ramping profile from 0 - 90 % H at 10 % RH increments, maintaining the sample at each step until equilibration had been attained (99% step completion). Upon reaching equilibration, the % RH within the apparatus was ramped to the next step and the equilibration procedure repeated. After completion of the sorption cycle, the sample was then dried using the same procedure. The weight change during the sorption/desorption cycles were then monitored, allowing for the hygroscopic nature of the sample to be determined. Simultaneous Thermal Analysis (STA) data were collected using the following method: Approximately 5 mg of sample was accurately weighed into a ceramic crucible and it was placed into the chamber of Perkin-Elmer STA 600 TGA/DTA analyzer at ambient temperature. The sample was then heated at a rate of 10°C/min, typically from 25°C to 300°C, during which time the change in weight was monitored as well as DTA signal. The purge gas used was nitrogen at a flow rate of 20 cm ³ /min.

Synthetic Examples

A. l-(4-Hydroxymethyl-benzyl)-lH-pyridin-2-one

4-(Chloromethyl)benzylalcohol (5.0 g, 31.93 mmol) was dissolved in acetone (150 mL). 2- hydroxypyridine (3.64 g, 38.3 mmol) and potassium carbonate (13.24 g, 95.78 mmol) were added and the reaction mixture was stirred at 50 °C for 3 hrs after which time the solvent was removed in vacuo and the residue taken up in chloroform (100 mL). This solution was washed with water (30 mL), brine (30 mL), dried (IN^SC ) and evaporated in vacuo. The residue was purified by flash chromatography (silica), eluent 3% MeOH / 97% CHCI ₃ , to give a white solid identified as l-(4-hydroxymethyl-benzyl)-lH- pyridin-2-one (5.30g, 24.62mmol, 77% yield). [M+Na] ⁺ = 238

B. l-(4-Chloromethyl-benzyl)-lH-pyridin-2-one

l-(4-Hydroxymethyl-benzyl)-lH-pyridin-2-one (8.45 g, 39.3 mmol), dry DCM (80 mL) and triethylamine (7.66 ml, 55.0 mmol) were cooled in an ice bath. Methanesulfonyl chloride (3.95 ml, 51.0 mmol) was added and stirred in ice bath for 15 min. The ice bath was removed and stirring continued at rt temperature overnight. The reaction mixture was partitioned between DCM (100 mL) and saturated aqueous N H4CI solution (100 mL). The aqueous layer was extracted with further DCM (2 x 50 mL) and the combined organics washed with brine (50 mL), dried over Na ₂ S0 ₄ , filtered and concentrated to give l-(4-chloromethyl-benzyl)-lH-pyridin-2-one (8.65 g, 36.6 mmol, 93 % yield) as a pale yellow solid.

[M+H] ⁺ = 234.1

C. Methyl 3-(methoxymethyl)-l-(4-((2-oxopyridin-l(2H)-yl)methyl)benzyl )-lH-pyrazole-4-carboxylate

Potassium carbonate (519 mg, 3.76 mmol) was added to a solution of methyl 3-(methoxymethyl)-lH- pyrazole-4-carboxylate (320 mg, 1.88 mmol; CAS no. 318496-66-1 (synthesised according to the method described in WO 2012/009009)) and l-(4-(chloromethyl)benzyl)pyridin-2(lH)-one (527 mg, 2.26 mmol) in DMF (5 mL) and heated at 60 °C overnight. The reaction mixture was diluted with EtOAc (50 mL) and washed with brine (2 x 100 mL), dried over magnesium sulfate, filtered and reduced in vacuo. The crude product was purified by flash chromatography (40 g column, 0-100% EtOAc in isohexanes) to afford two regioisomers. The second isomer off the column was collected to afford methyl 3-(methoxymethyl)-l-(4- ((2-oxopyridin-l(2H)-yl)methyl)benzyl)-lH-pyrazole-4-carboxy late (378 mg, 1.01 mmol, 53.7 % yield) as a colourless gum.

[M+H] ⁺ = 368.2 D. 3-(Methoxymethyl)-l-(4-((2-oxopyridin-l(2H)-yl)methyl)benzyl )-lH-pyrazole-4-carboxylic acid

To methyl 3-(methoxymethyl)-l-(4-((2-oxopyridin-l(2H)-yl)methyl)benzyl )-lH-pyrazole-4-carboxylate (3.77 g, 10.26 mmol) in THF (5 mL) and MeOH (5 mL) was added 2M NaOH solution (15.39 ml, 30.8 mmol) and stirred at rt overnight. 1M HCI (50 mL) was added and extracted with EtOAc (50 mL). The organic layer was washed with brine (50 mL), dried over magnesium sulfate, filtered and reduced in vacuo to give 3-(methoxymethyl)-l-(4-((2-oxopyridin-l(2H)-yl)methyl)benzyl )-lH-pyrazole-4-carboxylic acid (1.22 g, 3.45 mmol, 33.6 % yield) as a white powder.

[M+H] ⁺ = 354.2

E. N-[(2,6-Difluoro-3-methoxyphenyl)methyl1-3-(methoxymethyl)-l -({4-[(2-oxopyridin-l- yl)methyllphenyl}methyl)pyrazole-4-carboxamide (Form A) 3-(Methoxymethyl)-l-(4-((2-oxopyridin-l(2H)-yl)methyl)benzyl )-lH-pyrazole-4-carboxylic acid (621 mg, 1.76 mmol) and 2,6-difluoro-3-methoxy benzylamine (304 mg, 1.76 mmol) were dissolved in DCM at 0 °C. HOBt (285 mg, 2.11 mmol), triethylamine (1.23 mL, 8.79 mmol) and l-ethyl-3-(3- dimethylaminopropyl)carbodiimide (471.6 mg, 2.46 mmol) were added and the mixture was allowed to warm to rt. After stirring for 2 days, DCM (50 mL) was added and the mixture was washed with brine. The organic layer was dried over magnesium sulphate, filtered and concentrated in vacuo. The crude product was purified by flash chromatography (silica gel, 5% MeOH, 95% DCM), the solvents were removed in vacuo, the residue was taken up in acetonitrile and water and freeze dried to give a white solid identified as title compound.

[M+H] ⁺ = 509.0

^X H NM , (d6-DMSO): 3.20 (3H, s), 3.81 (3H, s), 4.43 (2H, d, J = 5.3Hz), 4.49 (2H, s), 5.06 (2H, s), 5.26 (2H, s), 6.21 (1H, dt, J = 1.4, 6.7Hz), 6.39 (1H, ddd, J = 0.7, 1.4, 9.1Hz), 7.02 (1H, dt, J = 1.9, 9.2Hz), 7.12 (1H, dt, J = 5.3, 9.3Hz), 7.18-7.27 (4H, m), 7.40 (1H, ddd, J = 2.1, 6.6, 9.2Hz), 7.75 (1H, ddd, J = 0.7, 2.1, 6.8Hz), 8.21 (1H, s), 8.24 (1H, t, J = 5.3Hz).

An XRPD diffractogram of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)-l -({4-[(2- oxopyridin-l-yl)methyl]phenyl}methyl)pyrazole-4-carboxamide (Form A) is shown in Figure 14.

Gravimetric Vapour Sorption (GVS)

The GVS data for Form A are listed in the table below and shown in

Figure 15.

N-[(2,6-difluoro-3-methoxyphenyl)methyl1-3-(methoxymethyl )-l-({4-[(2-oxopyridin-l- yl)methvHphenyl}methyl)pyrazole-4-carboxamide (Form 1)

A suspension of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)-l -({4-[(2-oxopyridin-l- yl)methyl]phenyl}methyl)pyrazole-4-carboxamide (200mg) in acetonitrile (2.0mL) was temperature- cycled between 40 °C and ambient temperature for about 18 - 24 hours overnight. The resulting product was dried initially by evaporation of excess solvent under nitrogen then in a vacuum oven at 50°C for approximately 6 hours to constant weight to afford N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3- (methoxymethyl)-l-({4-[(2-oxopyridin-l-yl)methyl]phenyl}meth yl)pyrazole-4-carboxamide (Form 1).

An X PD diffractogram of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)-l -({4-[(2- oxopyridin-l-yl)methyl]phenyl}methyl)pyrazole-4-carboxamide (Form 1) is shown in Figure 1.

Peak position table:

Simultaneous Thermal Analysis (STA)

The STA data for Form 1 are shown in Figure 2. Differential Scanning Calorimetry (DSC)

The DSC data for Form 1 are shown in Figure 3. Gravimetric Vapour Sorption (GVS)

The GVS data for Form 1 are listed in the table below and shown in Figure 4. Adsorption Desorption

%-RH %-Wt(dry basis) %-RH %-Wt(dry basis)

0.007 0.000001 89.98 4.172724

0.008 0.001373 85.005 2.90527

10.023 0.075445 75.011 1.652904

20.021 0.161862 65.02 1.032894

30.013 0.263368 55.026 0.647445

40.002 0.397795 44.976 0.455407

50.002 0.592577 34.982 0.290802

59.996 0.857316 24.99 0.193412

69.993 1.31135 14.995 0.090534

79.987 2.170037 5 0.046639

89.98 4.172724 0.32 0.002745

Stability data

A sample of Form 1 was placed in an open vial covered with tissue in a dessicator under accelerated stability conditions of 40 °C / 75%RH. The sample was reanalysed after 7 days and 28 days by XRPD, STA and DSC using the same methods as described above. The data is shown in Figure 6 to Figure 10.

Further samples of Form 1 were stored separately at two conditions of 40°C/75% RH for 6 months and 25°C/60% RH for 12 months packed into double polyethylene bags inside an HDPE bottle sealed with a screw cap closure. In this stability study X-Ray Powder Diffraction patterns were collected on a

PANalytical X' Pert PRO diffractometer using CuKct radiation (45 kV, 40 mA), θ- Θ goniometer, focusing mirror (Cu W/Si), divergence slit (1/2°), soller slits at both incident and diffracted beam (0.04 RAD), fixed mask (4 mm) and a PIXcel detector. The software used for data collection was X' Pert Data Collector, version 2.2f. The instrument was performance checked using a certified Standard Reference Material ^® 640d, Silicon Powder (N IST). XRPD patterns were acquired under ambient conditions via a transmission foil sample stage (polyimide - Kapton ^® , TF-475, 7.5μιη thickness film). The specimen was examined with approximately 5 mg of the sample examined as dispensed onto the sample stage. The data collection range was 2.994 - 35.0056°2Θ with a step size of 0.0263° and a continuous scan speed of 0.202004°s ^_1 . No change in the XRPD diffractogram was observed after 6 months at 40°C/75% RH or after 12 months at 25°C/60% RH (Figure 16).

Further tests on the samples of Form 1 stored at 25 °C / 60%RH and 40°C/75% RH were carried out as described in the table below. All measured parameters including Assay, Water Content, XRPD, DSC, Purity and Impurity Profile remained unchanged over the course of this study. Storage condition Initial 40°C / 75% H 25°C / 60% RH

Storage Time (months) 0 6 12

A white solid. Free

Appearance from visible As initial As initial

contamination

Assay (% w/w on an

100.18 99.31 99.94

anhydrous basis)

Analysis not

Assay (% w/w "as-is") 99.1 99.78

performed

Water content (% w/w) 0.19 0.17 0.12

XRPD Conforms to Form 1 As initial As initial

Onset = Peak = Onset = Peak = Onset = Peak =

DSC (°C)

156.3 158.9 157.5 159.8 156.8 159.5

Purity (% area) 100 99.9 100

Impurity 1.12 0.03 ND ND

Profile by Approx

HPLC RRT 1.16 ND 0.03 ND

(% area)

N-[(2,6-difluoro-3-methoxyphenyl)methvn-3-(methoxymethyl) -l-({4-[(2-oxopyridin-l- yl)methyllphenyl}methyl)pyrazole-4-carboxamide (Form 1)

To a 5 L flange flask under nitrogen was added N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-

(methoxymethyl)-l-({4-[(2-oxopyridin-l-yl)methyl]phenyl}m ethyl)pyrazole-4-carboxamide (159.6 g) and IPA (3.2 L). The mixture was heated to reflux to give a clear solution. The mixture was allowed to cool slowly to 50 °C before water cooling was applied. The solution was cooled from 50 °C to rt over 30 mins and optionally further cooled in an ice/water bath. The mixture was stirred at rt for 30 mins and filtered. The solid was washed with IPA (480 mL) and optionally further washed with diethyl ether. The solid was then dried over vacuum at 50 °C over the weekend to afford a total of 153.9 g of N-[(2,6-difluoro-3- methoxyphenyl)methyl]-3-(methoxymethyl)-l-({4-[(2-oxopyridin -l-yl)methyl]phenyl}methyl)pyrazole-4- carboxamide (Form 1) (153.9 g, 96%). ^X H NMR indicated a purity of >95%. LC indicated a purity of 99.8%. An XRPD diffractogram of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)-l -({4-[(2- oxopyridin-l-yl)methyl]phenyl}methyl)pyrazole-4-carboxamide isolated by recrystallization from isopropanol is shown in Figure 11 and confirms the identity of the solid as Form 1.

N-[(2,6-difluoro-3-methoxyphenyl)methvn-3-(methoxymethyl) -l-({4-[(2-oxopyridin-l- yl)methyllphenyl}methyl)pyrazole-4-carboxamide (Form 2) N-[(2,6-difluoro-3-methoxyphenyl)methy^

yl)methyl]phenyl}methyl)pyrazole-4-carboxamide was dissolved in a 50/50 methanol/water mixture. The solvent was allowed to evaporate and N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3- (methoxymethyl)-l-({4-[(2-oxopyridin-l-yl)methyl]phenyl}meth yl)pyrazole-4-carboxamide (Form 2) was isolated.

An X PD diffractogram of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)-l -({4-[(2- oxopyridin-l-yl)methyl]phenyl}methyl)pyrazole-4-carboxamide (Form 2) is shown in Figure 12.

Peak position table:

N-[(2,6-difluoro-3-methoxyphenyl)methyl1-3-(methoxymethyl )-l-({4-[(2-oxopyridin-l- yl)methvHphenyl}methyl)pyrazole-4-carboxamide (Form 3) N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)-l -({4-[(2-oxopyridin-l- yl)methyl]phenyl}methyl)pyrazole-4-carboxamide was dissolved in methanol. The solution was added to pentane. N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)-l -({4-[(2-oxopyridin-l- yl)methyl]phenyl}methyl)pyrazole-4-carboxamide (Form 3) was isolated from the resulting mixture. An X PD diffractogram of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)-l -({4-[(2- oxopyridin-l-yl)methyl]phenyl}methyl)pyrazole-4-carboxamide (Form 3) is shown in Figure 13. Peak position table:

Biological Methods

The ability of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)-l -({4-[(2-oxopyridin-l- yl)methyl]phenyl}methyl)pyrazole-4-carboxamide to inhibit plasma kallikrein may be determined using the following biological assays:

Determination of the IC ₅ o for plasma kallikrein

Plasma kallikrein inhibitory activity in vitro was determined using standard published methods (see e.g. Johansen et al., Int. J. Tiss. Reac. 1986, 8, 185; Shori et al., Biochem. Pharmacol., 1992, 43, 1209;

Sturzebecher et al., Biol. Chem. Hoppe-Seyler, 1992, 373, 1025). Human plasma kallikrein (Protogen) was incubated at 25 °C with the fluorogenic substrate H-DPro-Phe-Arg-AFC and various concentrations of the test compound. Residual enzyme activity (initial rate of reaction) was determined by measuring the change in optical absorbance at 410nm and the IC ₅ o value for the test compound was determined.

When tested in this assay, N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)-l -({4-[(2- oxopyridin-l-yl)methyl]phenyl}methyl)pyrazole-4-carboxamide showed an IC ₅ o (human PKal) of 4.5 nM.

N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl )-l-({4-[(2-oxopyridin-l- yl)methyl]phenyl}methyl)pyrazole-4-carboxamide was also screened for inhibitory activity against the related enzyme KLK1 using the following biological assay: Determination of the IC ₅ o for KLKl

KLKl inhibitory activity in vitro was determined using standard published methods (see e.g. Johansen et al., Int. J. Tiss. eac. 1986, 8, 185; Shori et al., Biochem. Pharmacol., 1992, 43, 1209; Sturzebecher et al., Biol. Chem. Hoppe-Seyler, 1992, 373, 1025). Human KLKl (Callbiochem) was incubated at 25 °C with the fluorogenic substrate H-DVal-Leu-Arg-AFC and various concentrations of the test compound.

Residual enzyme activity (initial rate of reaction) was determined by measuring the change in optical absorbance at 410nm and the IC ₅ o value for the test compound was determined.

When tested in this assay, N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)-l -({4-[(2- oxopyridin-l-yl)methyl]phenyl}methyl)pyrazole-4-carboxamide showed an IC ₅ o (human KLKl) of >10000 nM.

N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl )-l-({4-[(2-oxopyridin-l- yl)methyl]phenyl}methyl)pyrazole-4-carboxamide was also screened for inhibitory activity against the related enzyme FXIa using the following biological assay:

Determination of the % inhibition for FXIa

FXIa inhibitory activity in vitro was determined using standard published methods (see e.g. Johansen et al., Int. J. Tiss. Reac. 1986, 8, 185; Shori et al., Biochem. Pharmacol., 1992, 43, 1209; Sturzebecher et al., Biol. Chem. Hoppe-Seyler, 1992, 373, 1025). Human FXIa (Enzyme Research Laboratories) was incubated at 25 °C with the fluorogenic substrate Z-Gly-Pro-Arg-AFC and 40 μΜ of the test compound. Residual enzyme activity (initial rate of reaction) was determined by measuring the change in optical absorbance at 410nm. When tested in this assay, N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)-l -({4-[(2- oxopyridin-l-yl)methyl]phenyl}methyl)pyrazole-4-carboxamide showed a % inhibition @ 40 μΜ (human FXIa) of 4%.

Pharmacokinetics

A pharmacokinetic study of N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3-(methoxymethyl)-l -({4-[(2- oxopyridin-l-yl)methyl]phenyl}methyl)pyrazole-4-carboxamide was performed to assess the pharmacokinetics following a single oral dose in male Sprague-Dawley rats. Two rats were given a single po dose of 5 mL/kg of a nominal 2 mg/mL (10 mg/kg) composition of test compound in vehicle.

Following dosing, blood samples were collected over a period of 24 hours. Sample times were 5, 15 and 30 minutes then 1, 2, 4, 6, 8 and 12 hours. Following collection, blood samples were centrifuged and plasma fraction analysed for concentration of test compound by LCMS.

Oral exposure data acquired from this study for N-[(2,6-difluoro-3-methoxyphenyl)methyl]-3- (methoxymethyl)-l-({4-[(2-oxopyridin-l-yl)methyl]phenyl}meth yl)pyrazole-4-carboxamide is shown below:

Vehicle Dose po (mg/kg) Cmax (ng/mL) Tmax (min)

10% DM SO / 10%

11.3 2892 60

cremophor / 80% SWFI