WO2016114633A1 - Long-acting fgf21 fusion proteins and pharmaceutical composition comprising the same - Google Patents

Abstract

The present invention provides a fusion protein including a mutant protein of human FGF21 and an Fc region of a human immunoglobulin. The fusion protein according to the present invention exhibits improved pharmacological efficacy, in vivo duration, and protein stability, and a pharmaceutical composition including the fusion protein as an active ingredient may be effectively used as a therapeutic agent for diabetes, obesity, and lipid metabolism improvement.

Description

LONG-ACTING FGF21 FUSION PROTEINS AND PHARMACEUTICAL COMPOSITION COMPRISING THE SAME

The present invention relates to a fusion protein including a long-acting FGF21 mutant protein with improved pharmacological activity and in vivo stability, and a pharmaceutical composition including the same.

Fibroblast growth factor 21 (FGF21), which is synthesized in the liver, is a hormone known to play an important role in glucose and lipid homeostasis. FGF21 exhibits the pharmacological action in the liver, adipocytes, β cells of the pancreas, hypothalamus in brains and muscle tissues, where both an FGF21-specific receptor, i.e., FGF receptor, and β-klotho complex are expressed. Until now, it has been reported that, in mice and monkeys with various diabetic and obesity diseases, FGF21 lowered the blood glucose levels in an insulin-independent manner, and reduced body weights, and the concentrations of triglycerides and low-density lipoprotein (LDL) in the blood. Additionally, due to the effect of improving insulin sensitivity, FGF21 has the potential as a target of novel therapeutic agent for anti-diabetes and obesity (see WO2003/011213, WO2003/059270, WO2005/072769, and WO2013/033452).

Accordingly, in order to develop a novel anti-diabetic drug targeting to FGF21, attempts have been made to improve a biological activity and in vivo stability by constructing FGF21 mutants based on wild-type FGF21 via substitution, insertion, and deletion of some amino acids (see WO2005/061712, WO2006/029714, WO2006/065582, WO2010/065439, WO2011/154349, WO2013/052311, WO2013/131091, WO2013/188182, and WO2014/085365). However, since FGF21 has a very short half-life, FGF21 is problematic to be directly used as a biotherapeutic agent (see the document [Kharitonenkov, A. et al. (2005) Journal of Clinical Investigation 115:1627-1635]). The in vivo half-life of FGF21 is 1 hour to 2 hours in mice, and 2.5 hours to 3 hours in monkeys. Therefore, when the FGF21 is developed as a therapeutic agent for diabetes, daily administration thereof is required.

Until now, various technologies have been reported in order to increase in vivo half-life of the FGF21 recombinant protein. First, one example as such is to link polyethylene glycol (PEG), i.e., a polymer material, to FGF21 to increase molecular weight, thereby inhibiting renal excretion and increasing in vivo retention time (see WO2005/091944, WO2006/050247, WO2008/121563, and WO2012/066075). There is another example to improve the half-life by fusing a fatty acid, which binds to human albumin, to the FGF21 molecule (see WO2010/084169 and WO2012/010553).

Additionally, there is a further example to increase the half-life while exhibiting a pharmacological activity equivalent to that in the mechanism of FGF21 by preparing an agonist antibody, which specifically binds to a human FGF receptor alone or a complex with the β-klotho (see WO2011/071783, WO2011/130417, WO2012/158704, and WO2012/170438). Moreover, the half-life may be improved by preparing long-acting fusion proteins, in which an Fc region of an immunoglobulin G (IgG) binds to the FGF21 molecule (see WO2004/110472, WO2005/113606, WO2009/149171, WO2010/042747, WO2010/129503, WO2010/129600, WO2013/049247, and WO2013/188181).

Among the various long-acting technologies, the Fc fusion technology is most widely used, because it has less adverse actions such as trigger of immune response or toxicity due to an increase of in vivo half-life. For the development of the Fc-fused FGF21 protein as a long-acting therapeutic drug, the following various conditions should be satisfied. First, the decrease of in vitro activity caused by fusion should be minimized. Both the N-terminus and C-terminus of FGF21 are involved in the FGF21 activity. In this regard, it is known that the activities of FGF21 fusion proteins greatly vary depending on the location of the fusion. Accordingly, the activities of the FGF21 fusion proteins, in which mutations are introduced into FGF21, may be altered depending on the presence/absence or the location of the fusion. Second, a pharmacokinetic profile enabling administration at an interval of once per week in humans should be expressed due to the increase of in vivo half-life by the fusion. Third, considering that immunogenicity may occur in patients in most biopharmaceuticals, an immunogenicity risk due to a fusion linker or mutation should be minimized. Fourth, there should be no stability problem due to the position of the fusion or the introduction of a mutation. Fifth, since an undesired immune response may occur depending on the isotypes of a fused immunoglobulin, an alternate approach is required to prevent such response.

An attempt to develop a long-acting fusion protein by linking an Fc region of an immunoglobulin G (IgG) to the FGF21 molecule has been already reported (see WO2009/149171, WO2010/042747, WO2010/129503, WO2010/129600, WO2013/049247, and WO2013/188181). In case of an Fc-FGF21 structure, where the Fc is fused to the N-terminus of the wild-type FGF21 structure, there is no distinct difference in in vitro activity compared to that of the wild-type FGF21, but, the half-life is known to be very short by in vivo degradation of proteins. To improve this, there has been an attempt to improve the in vivo half-life by introducing several mutations having resistance to the protein degradation on specific locations of the FGF21. However, the immunogenicity risk may increase due to the introduction of multiple mutations. In contrast, in case of an FGF21-Fc structure, where the Fc is fused to the C-terminus of the FGF21 molecule, it is known that there is a significant decrease in activity by the fusion compared to the Fc-FGF21 structure. Until now, there has been no attempt to improve the activity in the FGF21-Fc structure or improve the pharmacokinetic profile thereof.

The present inventors have endeavored to improve the physiological activity and stability of FGF21 and discovered that the activity of FGF21 may be improved and the in vivo half-life may be increased when a mutation is introduced to a particular location of FGF21 and the immunoglobulin Fc region is linked thereto, thereby accomplishing the present invention.

Therefore, an object of the present invention is to provide a fusion protein including an FGF21 mutant protein with improved pharmacological efficacy, in vivo duration and protein stability.

Another object of the present invention is to provide a pharmaceutical composition including the fusion protein, and a method for preventing or treating diabetes, obesity, dyslipidemia, or metabolic syndrome by employing the pharmaceutical composition.

To achieve the above objects, the present invention provides a fusion protein including an Fc region of an immunoglobulin and an FGF21 mutant protein, where arginine, which is the 19^th amino acid of an amino acid sequence represented by SEQ ID NO: 1, is substituted with a different amino acid.

Further, the present invention provides a pharmaceutical composition including the fusion protein for treating FGF21-related diseases, and a method for preventing or treating the FGF21-related diseases.

The long-acting FGF21 fusion protein of the present invention with improved pharmacological efficacy, in vivo duration, and protein stability, which is prepared by linking an Fc region of a human immunoglobulin G (IgG) to an FGF21 mutant, and a pharmaceutical composition including the fusion protein as an active ingredient can be used as a therapeutic agent for diabetes, obesity and lipid metabolism improvement. In particular, the pharmaceutical composition of the present invention has an advantage of a long administration interval due to the increased in vivo stability compared with that of the conventional pharmaceutical composition including an FGF21 protein.

The above and other objects and features of the present invention will become apparent from the following description of the invention, when taken in conjunction with the accompanying drawings, which respectively show:

FIG. 1A is a graph showing the measurement results of in vitro activity of alanine point mutation at positions from the 19^th to the 22^nd of FGF21-Fc using HEK293 cell line where human β-klotho is overexpressed. It is shown that the point mutation at the 19^th position has the least reduction in activity.

FIG. 1B is a table showing the measurement results of in vitro activities of alanine point mutation of FGF21-Fc protein and the point mutation in the amino acid at the 19^th position of FGF21, indicated in relative values.

FIG. 2 is a graph showing the measurement results of in vitro activities of N00 and N12 using HEK293 cell line where human β-klotho is overexpressed. It is shown that N12 has an increased activity compared with that of N00 in the cell line where human β-klotho is overexpressed.

FIG. 3 is a graph showing the concentration of each protein in the blood versus time for 192 hours after subcutaneous administration of N00 and N12 to mice at a dose of 2 mg/kg, respectively. Data are indicated as mean values and standard deviation.

FIG. 4 shows that N12 has improved efficacy compared with N00 in an ob/ob diabetic mouse model. FIG. 4A shows graphs illustrating the non-fasted blood glucose levels measured in ob/ob mice subcutaneously injected with N00 and N12 at each administration dose. Data are indicated as mean values and standard error of the mean (S.E.M.).

FIG. 4B is a histogram showing the values for the area under the curve for the non-fasted blood glucose levels from the 0^th day to the 7^th day measured after subcutaneous administration of N00 and N12 depending on each dose, respectively.

FIG. 4C is plotted graphs showing the changes in percent of body weights in ob/ob mice from the day of administration to the 7^th day measured after subcutaneous injection of N00 and N12 depending on each dose, respectively. Data are indicated as mean values and standard error of the mean (S.E.M.).

FIG. 4D is a histogram showing the change in percent of body weight on the 4^th day compared with that of the baseline (the 0^th day) after administration of N00 and N12, respectively. Data are indicated as mean values and standard error of the mean (S.E.M.), and the test of significance among each experimental group was statistically treated relative to the vehicle-treated group of ob/ob mice, via Dunnett's test of one-way ANOVA, and then determined to be of statistical significance when the confidence interval (p value) is less than 0.05.

FIG. 5 shows the measurement results of in vitro activities of H05, H09, H11, and HyC in HEK293 cell line where human β-klotho is overexpressed. Data are indicated in EC₅₀ values.

FIG. 6 is a graph showing the concentration of each protein in the blood versus time for 192 hours measured after subcutaneous administration of H05, H09, H11 and HyC to mice at a dose of 2 mg/kg, respectively. Data are indicated as mean values and standard deviation.

FIG. 7 shows the efficacy test results depending on various types of hinges linking FGF21 and a hybrid Fc in an ob/ob diabetic mouse model. FIG. 7A shows a histogram illustrating the values for the area under the curve for the non-fasted blood glucose levels (the 7^th day from administration) measured in an ob/ob mouse model after injection of H05, H09 and H11 depending on each dose, respectively.

FIG. 7B is a histogram showing the change in percent of body weights on the 3^rd day compared with that of the baseline (the 0^th day) after administration of H05, H09 and H11, respectively. Data are indicated as mean values and standard error of the mean (S.E.M.), and the test of significance among each experimental group was statistically treated relative to the vehicle-treated group of ob/ob mice, via Dunnett's test of one-way ANOVA, and then determined to be of statistical significance when the confidence interval (p value) is less than 0.05.

FIG. 8 shows the measurement results of in vitro activities of H05 and H09 in HEK293 cell line where human β-klotho is overexpressed. Data are indicated as EC₅₀ values.

FIG. 9 shows that M09 has improved efficacy compared with H05 in an ob/ob diabetic mouse model. FIG. 9A shows graphs illustrating the non-fasted blood glucose levels measured in ob/ob mice subcutaneously injected with H05 and M09 at each administration dose. Data are indicated as mean values and standard error of the mean (S.E.M.).

FIG. 9B is a histogram showing the values for the area under the curve for the non-fasted blood glucose levels from the 0^th day to the 7^th day measured after subcutaneous injection of H05 and M09 depending on each dose, respectively.

FIG. 9C is plotted graphs showing the changes in percent of body weights in ob/ob mice from the onset of administration to the 7^th day measured after subcutaneous injection of H05 and M09 depending on each dose, respectively. Data are indicated as mean values and standard error of the mean (S.E.M.).

FIG. 9D is a histogram showing the change in percent of body weights on the 4^th day compared with that of the baseline (the 0^th day) after administration of H05 and M09, respectively. Data are indicated as mean values and standard error of the mean (S.E.M.), and the test of significance among each experimental group was statistically treated relative to the vehicle-treated group of ob/ob mice, via Dunnett's test of one-way ANOVA, and then determined to be of statistical significance when the confidence interval (p value) is less than 0.05.

FIG. 10 shows the measurement results of in vitro activities of H05 and H40 in HEK293 cell line where human β-klotho is overexpressed. Data are indicated as EC₅₀ values.

FIG. 11 is a graph showing the drug concentration in the blood versus time for 192 hours after subcutaneous administration of H05 and H40 to mice at a dose of 2 mg/kg, respectively. Data are indicated as mean values and standard deviation.

FIG. 12 shows that H40 has improved efficacy compared with H05 in an ob/ob diabetic mouse model. FIG. 12A shows plotted graphs illustrating the dose-response of non-fasted blood glucose in ob/ob mice subcutaneously injected with H05 and H40. Data are indicated as mean values and standard error of the mean (S.E.M.).

FIG. 12B is a histogram showing the values for the area under the curve for the non-fasted blood glucose levels from the 0^th day to the 7^th day measured after subcutaneous injection of H05 and H40, respectively.

FIG. 12C is graphs showing the changes in percent of body weights in ob/ob mice from the onset of administration to the 7^th day measured after subcutaneous injection of H05 and H40, respectively. Data are indicated as mean values and standard error of the mean (S.E.M.).

FIG. 12D is a histogram showing the change in percent of body weights on the 7^th day compared with that of the baseline (the 0^th day) after subcutaneous administration of various dose of H05 and H40, respectively. Data are indicated as mean values and standard error of the mean (S.E.M.), and the test of significance among each experimental group was statistically treated relative to the vehicle-treated group of ob/ob mice, via Dunnett's test of one-way ANOVA, and then determined to be of statistical significance when the confidence interval (p value) is less than 0.05.

FIG. 13 shows the measurement results of in vitro activities of M09 and F09 in HEK293 cell line where human β-klotho is overexpressed. Data is indicated as EC₅₀ values.

FIG. 14A is a graph showing the concentration of each protein in the blood versus time for 192 hours after subcutaneous administration of M09 and F09 to mice at a dose of 2 mg/kg, respectively. Data are indicated as mean values and standard deviation.

FIG. 14B is a graph showing the concentration of each protein in the blood versus time for 192 hours after subcutaneous administration of M09 and F09 to rats at a dose of 1 mg/kg, respectively. Data are indicated as mean values and standard deviation.

FIG. 15 shows that F09, which is a long-acting FGF21 mutant, has improved efficacy compared with M09 in an ob/ob diabetic mouse model. FIG. 15A shows plotted graphs illustrating the dose-response of the non-fasted blood glucose in ob/ob mice subcutaneously injected with M09 and F09. Data are indicated as mean values and standard error of the mean (S.E.M.).

FIG. 15B is a histogram showing the values for the area under the curve for the non-fasted blood glucose from the 0^th day to the 7^th day measured after a single injection of M09 and F09, respectively.

FIG. 16 shows that F09, which is a long-acting FGF21 mutant, has an improved anti-obesity effect compared with M09 in a diet-induced obese mouse model. FIG. 16A shows plotted graphs illustrating the dose-response of changes in body weights in a diet-induced obese mouse model subcutaneously injected with M09 and F09 as a single administration or once weekly administration during 2 weeks. Data are indicated as mean values and standard error of the mean (S.E.M.).

FIG. 16B is a histogram showing the changes in body weights on the 7^th day and the 14^th day compared with that of the administration point (the 0^th day) in a diet-induced obese mouse model subcutaneously injected with M09 and F09 as a single administration or once weekly administration during 2 weeks. Data are indicated as mean values and standard error of the mean (S.E.M.).

FIG. 17 shows efficacy test results of F09, which is a long-acting FGF21 mutant, depending on the administration dose and number of injections in a db/db diabetic mouse model. FIG. 17A shows plotted graphs illustrating the dose-response of the non-fasted blood glucose in db/db mice after subcutaneous injection of as a single administration or twice weekly (0^th day, 4^th day) administration during 2 weeks. Data are indicated as mean values and standard error of the mean (S.E.M.).

FIG. 17B is a histogram showing the values for the area under the curve for the non-fasted blood glucose from the 0^th day to the 7^th day measured after single administration or twice weekly administration of F09 in db/db mice, respectively.

FIG. 17C is graphs showing the changes in body weights in db/db mice from the day of administration to the 7^th day after single administration or twice weekly administration of F09. Data are indicated as mean values and standard error of the mean (S.E.M.).

FIG. 17D is a histogram showing the changes in body weights in db/db mice on the 7^th day compared with that of the day of administration of F09 (the 0^th day). Data are indicated as mean values and standard error of the mean (S.E.M.), and the test of significance among each experimental group was statistically treated relative to the vehicle-treated group of db/db mice, via Dunnett's test of one-way ANOVA, and then determined to be of statistical significance when the confidence interval (p value) is less than 0.05.

Hereinafter, the present invention will be described in more detail.

In an aspect, the present invention provides a fusion protein including an Fc region of an immunoglobulin and an FGF21 mutant protein, where arginine, which is the 19^th amino acid of an amino acid sequence represented by SEQ ID NO: 1, is substituted with a different amino acid.

The FGF21, a fibroblast growth factor, is a hormone known to play an important role in glucose and lipid homeostasis. The FGF21 may be one derived from mammals such as humans, mice, pigs, monkeys, etc., preferably from humans. More preferably, the FGF21 may have an amino acid sequence represented by SEQ ID NO: 1. In an exemplary embodiment, the FGF21 may be a mutant protein, in which the 19^th amino acid of SEQ ID NO: 1, i.e., arginine, is substituted with tyrosine. Further, the FGF21 mutant protein may include a protein in which the 19^th amino acid of SEQ ID NO: 1 is tyrosine and 1 to 10 amino acids at the N-terminus or C-terminus is(are) deleted compared to the wild-type FGF21.

Furthermore, the immunoglobulin Fc region may be an entire Fc region constituting an antibody, a fragment thereof, or an Fc region mutant. As used herein, the term "Fc region," "Fc fragment," or "Fc" refers to a protein, which includes a heavy chain constant region 1 (CH1), a heavy chain constant region 2 (CH2) and a heavy chain constant region 3 (CH3) of an immunoglobulin, but does not include variable regions of the heavy- and light chains and a light chain constant region 1 (CL1). Additionally, the Fc region includes a molecule in the form of a monomer or a multimer. Moreover, the Fc region may further include a hinge region of the heavy chain constant region.

As used herein, the term “Fc region mutant” refers to one which is prepared by substituting a part of amino acid(s) of an Fc region or by combining Fc regions of different types. The Fc region mutant may be modified to prevent from being cut off at the hinge region.

In an exemplary embodiment, the Fc region of the immunoglobulin may be any one of IgG1, IgG2, IgG3, IgG4 or IgD region, or a hybrid Fc, which is a combination thereof. Further, the hybrid Fc may include an IgG4 region and an IgD region. Further, the hybrid Fc region may include a part of the hinge sequence of an IgG4 Fc, CH2 and CH3 sequences. Furthermore, the hinge sequence of the IgG4 Fc may have substitution in some amino acid sequences to reduce antibody-dependent cell-mediated cytotoxicity (ADCC) or complement-dependent cytotoxicity (CDC). In addition, a part of the amino acid sequence of the IgG4 Fc hinge sequence may be substituted to inhibit the rearrangement of the Fab region. A lysine residue at the C-terminus of the IgG4 Fc may be removed.

Additionally, the Fc fragment of the present invention may be in the form of wild-type glycosylated chain, more glycosylated chain than the wild-type, less glycosylated chain than the wild-type, or deglycosylated chain. The increase, decrease, or removal of glycosylation of an immunoglobulin Fc may be performed by a conventional method known in the art, such as a chemical method, an enzymatic method, and a genetic engineering method using microorganisms.

Further, in an exemplary embodiment of the fusion protein, the immunoglobulin Fc region may include an amino acid sequence of SEQ ID NO: 4 or SEQ ID NO: 5.

Additionally, the fusion protein may further include a linker. The fusion protein may be in the form, in which the FGF21 mutant protein is directly linked to the N-terminus or C-terminus of the immunoglobulin Fc region, or may be linked via a linker.

In this case, the linker may be linked to the N-terminus, C-terminus, or a free radical of the Fc fragment, and also, may be linked to the N-terminus, C-terminus, or a free radical of the FGF21 mutant protein. When the linker is a peptide linker, the linking may occur in any linking region. When the linker and Fc are separately expressed and then linked, the linker may be a crosslinking agent known in the art.

Examples of the crosslinking agent may include 1,1-bis(diazoacetyl)-2-phenylethane, glutaraldehyde, imidoesters including N-hydroxysuccinimide ester such as 4-azidosalicylic acid and disuccinimidyl esters such as 3,3'-dithiobis (succinimidylpropionate), and bifunctional maleimides such as bis-N-maleimido-1,8-octane, but are not limited thereto.

Further, the linker may be a peptide. In this case, the linker may be a peptide consisting of 10 to 20 amino acid residues including glycine and serine residues. Furthermore, alanine may additionally be attached to both ends of the linker. Preferably, the linker may be a peptide having an amino acid sequence of SEQ ID NO: 2 or SEQ ID NO: 3.

Additionally, the fusion protein may be in a form of a dimer, in which one or more FGF21 mutant proteins are linked, or in a form in which a multimer FGF21 mutant protein is linked to an immunoglobulin Fc region. Additionally, the fusion protein may be in a form of a dimer or multimer, to which two or more immunoglobulin Fc regions are linked, wherein the immunoglobulin Fc regions have the FGF21 mutant protein linked thereto.

Additionally, the fusion protein including the FGF21 mutant protein may be a peptide which preferably includes an amino acid sequence represented by SEQ ID NO: 18, SEQ ID NO: 39, or SEQ ID NO: 40.

In another aspect, the present invention provides a pharmaceutical composition including the fusion protein for treating FGF21-associated disorders.

As used herein, the term “FGF21-associated disorder” may include obesity, type I-and type II diabetes, pancreatitis, dyslipidemia, non-alcoholic fatty liver disease (NAFLD), nonalcoholic steatohepatitis (NASH), insulin resistance, hyperinsulinemia, glucose intolerance, hyperglycemia, metabolic syndrome, acute myocardial infarction, hypertension, cardiovascular diseases, atherosclerosis, peripheral arterial disease, apoplexy, heart failure, coronary artery heart disease, renal disease, diabetic complications, neuropathy, gastroparesis, disorder associated with a serious inactivation mutation in insulin receptor, and other metabolic disorders. Preferably, the FGF21-associated disorder may be diabetes, obesity, dyslipidemia, or metabolic syndrome.

Further, the pharmaceutical composition may further include a pharmaceutical carrier. The pharmaceutical carrier may be any carrier as long as it is a non-toxic material suitable for delivering antibodies to patients. For example, distilled water, alcohol, fats, waxes, and inactive solids may be included as a carrier. Pharmaceutically acceptable adjuvants (buffering agents, dispersants) may also be included in the pharmaceutical composition. In these formulations, the concentration of the fusion protein may vary greatly. For example, the concentration may be about 0.5% or less, or generally at least from about 1% to 15% or 20% depending on the weight, and may be selected primarily based on the volume of body liquid, viscosity, etc., according to the selected particular administration method.

Specifically, the pharmaceutical composition may contain a formulating material for altering, maintaining, or conserving the pH, osmolarity, viscosity, transparency, color, isotonicity, odor, asepticism, stability, solubility, or release rate, adsorption, or permeability of the composition. Examples of the suitable formulating material may include amino acids (e.g., glycine, glutamine, asparagine, arginine, or lysine), anti-microorganism agents, anti-oxidants (e.g., ascorbic acid, sodium sulfite, or sodium bisulfite), buffering agents (e.g., borate, bicarbonates, Tris-HCl, citrate, phosphate, or other organic acids), bulking agents (e.g., mannitol or glycine), chelating agents (e.g., ethyelenediaminetetraacetic acid (EDTA), complexing agents (e.g., caffeine, polyvinylpyrrolidione, β-cyclodextrin, or hydroxypropyl-β-cyclodextrin), fillers, monosaccharides, disaccharides, and other carbohydrates (e.g., glucose, mannose, or dextrin), proteins (e.g., serum albumin, gelatin, or immunoglobulin), coloring agents, flavoring agents, diluents, emulsifiers, hydrophilic polymers (e.g., polyvinylpyrrolidione), low molecular weight polypeptides, salt-forming counterions (e.g., sodium), preservatives (e.g., benzalkonium chloride, benzoic acid, salicylic acid, thimerosal, phenethyl alcohol, methylparaben, propylparaben, chlorhexidine, sorbic acid or hydrogen peroxide), solvents (e.g., glycerin, propylene glycol, or polyethylene glycol), sugar alcohols (e.g., mannitol or sorbitol), suspending agents, surfactants, or humectants (e.g., pluronics; PEG; sorbitan ester; polysorbate, e.g., polysorbate 20 or polysorbate 80; triton; tromethanimine; lecithin; cholesterol or tyloxapol), stability improvers (e.g., sucrose or sorbitol), growth improvers (e.g., alkali metal halides; preferably, sodium chloride or potassium chloride; or mannitol sorbitol), delivery vehicles, diluents, excipients and/or pharmaceutical adjuvants, but not limited to.

In another aspect, the present invention provides a method for preventing or treating FGF21-associated disorders including administering the fusion protein to a subject in need of treatment. This method includes, in particular, administering an effective amount of the FGF21 fusion protein of the present invention to a mammal having diabetes, obesity, dyslipidemia, or a symptom of metabolic syndrome which are FGF21-associated disorders.

The pharmaceutical composition of the present invention may be administered via any route. The composition of the present invention may be provided to an animal directly (e.g., topically, by administering into tissue areas by injection, transplantation, or by topical administration) or systemically (e.g., by oral- or parenteral administration) via any appropriate means. When the composition of the present invention is parenterally provided via intravenous-, subcutaneous-, ophthalmic-, intraperitoneal-, intramuscular-, oral-, rectal-, intraorbital-, intracerebral-, intracranial-, intraspinal-, intraventricular-, intrathecal-, intracistenal-, intracapsular-, intranasal-, or aerosol administration, the composition is preferably aqueous or may include a part of a physiologically applicable body liquid suspension or solution. Accordingly, since the carrier or vehicle is physiologically applicable, the carrier or vehicle may be added to a composition and be delivered to a patient. Therefore, a physiological saline may generally be included as a carrier like a body fluid for formulations.

Further, the administration frequency may vary depending on the pharmacokinetic parameters of the FGF21 mutant protein in the formulations to be used. Typically, physicians would administer the composition until an administration dose to achieve a desired effect is reached. Accordingly, the composition may be administered as a unit dose at least two doses with time intervals (may or may not contain the same amount of a target molecule) or administered by a continuous injection via a transplantation device or catheter. The precision of addition of an appropriate administration dose may be routinely performed by a skilled person in the art, and corresponds to the business scope being routinely performed by them.

Additionally, the preferable unit dose of the fusion protein in humans may be in a range from 0.1 ㎍/kg to 100 mg/kg, and more preferably from 0.01 mg/kg to 10 mg/kg. Although this is the optimal amount, the unit dose may vary depending on the disease to be treated or the presence/absence of adverse effects. Nevertheless, the optimal administration dose may be determined by performing a conventional experiment. The administration of the fusion protein may be performed by a periodic bolus injection, an external reservoir (e.g., an intravenous bag), or a continuous intravenous-, subcutaneous-, or intra-abdominal administration from the internal (e.g., a bioerodable implant).

Additionally, the fusion protein of the present invention may be administered to a subject/recipient along with other biologically active molecules. However, the optimal combination between the fusion protein and other molecule(s), dosage forms, and optimal doses may be determined by a conventional experiment well known in the art.

In still another aspect, the present invention provides an isolated nucleic acid molecule encoding the fusion protein.

As used herein, the term “isolated nucleic acid molecule” refers to a nucleic acid molecule of the present invention, which is isolated from about at least 50% of proteins, lipids, carbohydrates, or other materials, discovered in nature along with a supply cell when total nucleic acid is isolated from the supply cell; which is operatively linked to a polynucleotide which is not linked in nature; or which is a part of a larger polynucleotide sequence and does not occur in nature. Preferably, in the isolated nucleic acid molecules of the present invention, there are not substantially present any other contaminated nucleic acids, or other contaminants which are discovered in natural environment and inhibit uses of the nucleic acids in the production of polypeptides, or treatment, diagnosis, prevention, or research.

In this case, the isolated nucleic acid molecules encoding the fusion protein may have different sequences with each other due to codon redundancy. Furthermore, as long as the isolated nucleic acid can produce the fusion protein, the isolated nucleic acid may be appropriately modified or a nucleotide is added to the N-terminus or C-terminus of the isolated nucleic acid according to the intended purposes.

In still another aspect, the present invention provides an expression vector including an isolated nucleic acid molecule, which encodes the fusion protein consisting of the FGF21 fusion protein and an Fc region of an immunoglobulin.

As used herein, the term “expression vector” refers to a vector containing a nucleic acid sequence, which is suitable for the transformation of a host cell and directs or controls the inserted heterogenous nucleic acid sequence. The expression vector includes a linear nucleic acid, a plasmid, a phagemid, a cosmid, an RNA vector, a viral vector, and analogs thereof. Examples of the viral vector include a retrovirus, an adenovirus, and an adeno-associated virus, but not limited thereto. As used herein, the term “expression of the heterogeneous nucleic acid sequence” or “expression” of a target protein refers to transcription of an inserted DNA sequence, translation of an mRNA transcript, and production of an Fc fusion protein product, an antibody or an antibody fragment.

A useful expression vector may be an RcCMV (Invitrogen, Carlsbad) or a mutant thereof. The useful expression vector may include a human cytomegalovirus (CMV) promoter for promoting a continuous transcription of a target gene in a mammalian cell and a bovine growth hormone polyadenylation signal sequence for increasing the level of post-transcriptional RNA stability. In an exemplary embodiment of the present invention, the expression vector is pAD15, which is a modified vector of the RcCMV.

In still another aspect, the present invention provides a host cell including the expression vector.

As used herein, the term “host cell” refers to a prokaryotic cell or a eukaryotic cell into which a recombinant expression vector may be introduced. As used herein, the term “transformed” or “transfected” refers to an introduction of a nucleic acid (e.g., a vector) into a cell by numerous technologies known in the art.

An appropriate host cell may be transformed or transfected with the DNA sequence of the present invention and may be used for the expression and/or secretion of the target protein. Examples of the appropriate host cell that may be used in the present invention include immortal hybridoma cells, NS/0 myeloma cells, 293 cells, Chinese hamster ovary (CHO) cells, HeLa cells, CAP cells (human amniotic fluid-derived cells), and COS cells.

Hereinbelow, exemplary embodiments of the present invention will be described in detail with reference to the examples. However, these examples according to the present invention can be embodied in many different forms and the scope of the present invention should not be construed as limited to the examples set forth herein.

Preparation Example 1. Preparation and screening of fusion protein including FGF21 mutant

Preparation Example 1-1. Preparation of expression vector for expression of FGF21 mutant protein

In order to increase the biological activity of the FGF21 in the FGF21-Fc structure, mutation studies were performed. First, each of the amino acids at positions of 19, 20, 21, and 22, which were expected to affect significantly on protein activities through the 3-dimensional structure analysis of the FGF21 proteins, was substituted with alanine, and the fusion proteins to which the IgG4 Fc mutants were linked were prepared as shown in Table 1 below.

Fusion proteins including FGF21 mutant protein

Material Code	Change in FGF21 sequence	Fusion carrier	Linker sequence	SEQ ID NO
N00	None	IgG4 Fc mutant(SEQ ID NO: 5)	GS3A(SEQ ID NO: 3)	SEQ ID NO: 6
N01	R19A	IgG4 Fc mutant(SEQ ID NO: 5)	GS3A(SEQ ID NO: 3)	SEQ ID NO: 7
N02	Y20A	IgG4 Fc mutant(SEQ ID NO: 5)	GS3A(SEQ ID NO: 3)	SEQ ID NO: 8
N03	L21A	IgG4 Fc mutant(SEQ ID NO: 5)	GS3A(SEQ ID NO: 3)	SEQ ID NO: 9
N04	Y22A	IgG4 Fc mutant(SEQ ID NO: 5)	GS3A(SEQ ID NO: 3)	SEQ ID NO: 10

Specifically, the nucleotide sequences encoding each of the FGF21 mutant proteins were synthesized by consulting to Bioneer Corporation (Korea) based on amino acid sequences of each protein. NheI and NotI restriction enzyme sequences were added to the 5’ terminus and 3’ terminus of each nucleotide sequence encoding the FGF21 mutant proteins and an initiation codon for protein translation and a leader sequence capable of secreting the expressed protein to outside of a cell were inserted next to the restriction enzyme sequence at the 5’ terminus. A termination codon was inserted next to the nucleotide sequence, which encodes each of the mutant proteins of the FGF21 proteins. The nucleotide sequences encoding each of the FGF21 mutant proteins were cloned into pTrans-empty expression vector using the two restriction enzymes of NheI and NotI. The pTrans-empty expression vector was purchased from CEVEC Pharmaceuticals (Germany) and this expression vector has a simple structure including a CMV promoter, a pUC-derived replication origin, an SV40-derived replication origin and an ampicillin-resistant gene.

Preparation Example 1-2. Construction of plasmid DNA for expression of FGF21 mutant protein

E. coli was transformed with each of the expression vectors constructed in Preparation Example 1-1 and a large amount of plasmid DNA to be used for expression was obtained. E . coli cells, whose cell wall was weakened through heat shock, were transformed with each expression vector, and the transformants were plated out on an LB plate to obtain colonies. The thus-obtained colonies were inoculated into an LB medium, cultured for 16 hours, and each E. coli intracellularly including each expression vector in an amount of 100 mL was obtained. The thus-obtained E. coli was centrifuged to remove the culture medium, and then added with P1, P2, P3 solutions (QIAGEN, Cat No.:12963) to break cell walls, thereby obtaining a DNA suspension in which proteins and DNA were separated. Plasmid DNA was purified from the thus-obtained solution using a Qiagen DNA purification column. The eluted DNA was identified through an agarose gel electrophoresis, and concentrations and purities were measured by using a nanodrop device (Thermo scientific, Nanodrop Lite). The resultant was used for expression.

Preparation Example 1-3. Expression of FGF21 mutant proteins in CAP-T cells

Human cell lines were transfected with each plasmid DNA separated in Preparation Example 1-2. Each plasmid DNA was transfected into CAP-T cells (CEVEC), which had been cultured in a PEM medium (Life technologies), using a PEI solution (Polyplus, Cat. No.:101-10N). The mixed solution of DNA and the PEI solution was mixed with the cells suspension using a Freestyle293 expression medium (Invitrogen), cultured for 5 hours, and added with a PEM medium. After culturing for 7 days, the culture was centrifuged to remove cells and a supernatant including FGF21 mutant proteins was obtained.

Preparation Example 1-4. Purification of fusion proteins having FGF21 mutant proteins and an Fc region

Protein A affinity chromatography column was equilibrated with a 20 mM sodium phosphate (pH 7.0) buffer solution. The culture supernatant including each FGF21 mutant protein was filtered with 0.2 μm filter and loaded into the Protein A affinity chromatography (GE Healthcare) column. The column was washed with a 20 mM sodium phosphate buffer solution and FGF21 mutant proteins were eluted using a 100 mM glycine (pH 3.0) buffer solution. The proteins obtained by affinity chromatography were purified using a hydroxyapatite (CHT hydroxyapatite Type I 40 μm, Bio-Rad) column. The hydroxyapatite column was equilibrated using a 5 mM sodium phosphate (pH 6.8) buffer solution, and then the proteins eluted by affinity chromatography were loaded thereto.

After washing the column with a 5 mM sodium phosphate (pH 6.8) buffer solution, a 500 mM sodium phosphate (pH 6.8) buffer solution was flowed along the concentration gradient and the eluted fractions were analyzed. Each eluted fraction was analyzed under SDS-PAGE reducing conditions and the fractions including FGF21 mutant proteins with high purity were collected, and dialyzed at 4℃ using a final buffer solution (1X PBS, 1 mM EDTA, pH 7.4) overnight. Upon completion of the dialysis, the resultant was concentrated at 4℃ at 3,000 rpm using 30,000 MW cut-off centrifugation filter. The concentration of FGF21 mutant proteins was measured via BCA quantitative analysis.

Experimental Example 1. Screening of fusion proteins including FGF21 mutant proteins

The in vitro activities of fusion proteins N01, N02, N03 and N04, prepared in Preparation Example 1, were measured. Specifically, the in vitro activities of the fusion proteins were evaluated using the HEK293 cell line which was constructed so that β-klotho, a coreceptor of FGF21, was overexpressed. For the evaluation of activity, wild-type FGF21 was subjected to a 3-fold serial dilution at a concentration of 200 nM and the samples including fusion proteins were subjected to a 3-fold serial dilution at a concentration of 30 μM. The human β-klotho overexpressing HEK293 cell line, which was cultured in a serum-deficient state for 5 hours, was treated with the diluted wild-type FGF21 and the samples including fusion preteins for 20 minutes, and the cells were lysed. The cell lysate solution was mixed with antibodies which can detect ERK and phosphorylated ERK and reacted at room temperature for 2 hours. The fluorescence was detected. The FGF21 activities of the samples including the fusion proteins were measured compared with that of N00, which is a fusion protein prepared by linking an IgG4 Fc to the wild-type FGF21 protein.

As a result, when the FGF21 activity of the four fusion proteins were compared with that of N00, which is the fusion protein prepared by linking an IgG4 Fc to the wild-type FGF21 protein, the activity reduction was the least when arginine (R), the amino acid residue at position 19 of the wild-type FGF21, was substituted with alanine (A). Accordingly, the 19^th position of the wild-type FGF21 was confirmed to be most important.

Preparation Example 2. Preparation and screening of fusion proteins including FGF21 mutant protein having a mutation at 19th position of wild-type FGF21

Fusion proteins (N05 to N22) including FGF21 mutant proteins, in which the 19^th amino acid, arginine, was substituted with 18 different amino acids, other than alanine, shown in Table 2, were prepared in accordance with the methods described in Preparation Examples 1-1 to 1-4.

Fusion proteins including the FGF21 mutant proteins having a mutation at the 19^th position of wild-type FGF21

Material Code	Change in FGF21 sequence	Fusion carrier	Linker sequence	SEQ ID NO
N05	R19E	IgG4 Fc mutant (SEQ ID NO: 5)	GS3A(SEQ ID NO: 3)	SEQ ID NO: 11
N06	R19H	IgG4 Fc mutant (SEQ ID NO: 5)	GS3A(SEQ ID NO: 3)	SEQ ID NO: 12
N07	R19N	IgG4 Fc mutant (SEQ ID NO: 5)	GS3A(SEQ ID NO: 3)	SEQ ID NO: 13
N08	R19M	IgG4 Fc mutant (SEQ ID NO: 5)	GS3A(SEQ ID NO: 3)	SEQ ID NO: 14
N09	R19S	IgG4 Fc mutant (SEQ ID NO: 5)	GS3A(SEQ ID NO: 3)	SEQ ID NO: 15
N10	R19T	IgG4 Fc mutant (SEQ ID NO: 5)	GS3A(SEQ ID NO: 3)	SEQ ID NO: 16
N11	R19P	IgG4 Fc mutant (SEQ ID NO: 5)	GS3A(SEQ ID NO: 3)	SEQ ID NO: 17
N12	R19Y	IgG4 Fc mutant (SEQ ID NO: 5)	GS3A(SEQ ID NO: 3)	SEQ ID NO: 18
N13	R19F	IgG4 Fc mutant (SEQ ID NO: 5)	GS3A(SEQ ID NO: 3)	SEQ ID NO: 19
N14	R19L	IgG4 Fc mutant (SEQ ID NO: 5)	GS3A(SEQ ID NO: 3)	SEQ ID NO: 20
N15	R19I	IgG4 Fc mutant (SEQ ID NO: 5)	GS3A(SEQ ID NO: 3)	SEQ ID NO: 21
N16	R19V	IgG4 Fc mutant (SEQ ID NO: 5)	GS3A(SEQ ID NO: 3)	SEQ ID NO: 22
N17	R19Q	IgG4 Fc mutant (SEQ ID NO: 5)	GS3A(SEQ ID NO: 3)	SEQ ID NO: 23
N18	R19K	IgG4Fc mutant (SEQ ID NO: 5)	GS3A(SEQ ID NO: 3)	SEQ ID NO: 24
N19	R19D	IgG4 Fc mutant (SEQ ID NO: 5)	GS3A(SEQ ID NO: 3)	SEQ ID NO: 25
N20	R19C	IgG4 Fc mutant (SEQ ID NO: 5)	GS3A(SEQ ID NO: 3)	SEQ ID NO: 26
N21	R19W	IgG4 Fc mutant (SEQ ID NO: 5)	GS3A(SEQ ID NO: 3)	SEQ ID NO: 27
N22	R19G	IgG4 Fc mutant (SEQ ID NO: 5)	GS3A(SEQ ID NO: 3)	SEQ ID NO: 28

The in vitro activities of the thus-obtained fusion proteins were measured in the same manner as in Experimental Example 1. As a result of evaluation of the in vitro activities of the N05 to N22 compared to that of N00, the in vitro activities were reduced in all mutants, except the N12. N12 showed about a 6-fold increase in activity compared to that of N00.

Preparation Example 3. Preparation and screening of fusion proteins including FGF21 mutant protein having hybrid Fc

Fusion proteins were prepared by linking wild-type FGF21 or FGF21 mutant protein having substitution at the 19^th position of the wild-type, from arginine to tyrosine, to hybrid Fc, as shown in Table 3 below in accordance with the method described in Preparation Examples 1-1 to 1-4.

FGF21 fusion proteins including hybrid Fc

Material Code	Change in FGF21 sequence	Fusion carrier	Linker sequence	SEQ ID NO
H05	None	hyFc5(SEQ ID NO: 29)	-	SEQ ID NO: 34
H09	None	hyFc9(SEQ ID NO: 30)	-	SEQ ID NO: 35
H11	None	hyFc11(SEQ ID NO: 31)	-	SEQ ID NO: 36
HyC	-	hyFc-C(SEQ ID NO: 32)	-	SEQ ID NO: 37
H40	None	hyFc40(SEQ ID NO: 33)	-	SEQ ID NO: 38
M09	R19Y	hyFc5(SEQ ID NO: 29)	-	SEQ ID NO: 39
F09	R19Y	hyFc40(SEQ ID NO: 33)	-	SEQ ID NO: 40

The in vitro activities were evaluated in the same method as in Experimental Example 1. As a result of measurement of EC₅₀ values for each of the fusion proteins, the in vitro activity of the H05 was most excellent. In case of the HyC, the activity measured via measurement of EC₅₀ value was excellent, but the E_max value was slightly low.

Experimental Example 2. Measurement result of in vitro activities of fusion proteins

Experimental Example 2-1. Experimental results of N00 and N12

For the evaluation of the activities of fusion proteins including FGF21 depending on a mutation on the 19^th amino acid of FGF21, experiments were performed on N00 and N12. As a result, it was confirmed that the in vitro activity of N12 was increased 6 times compared to that of N00. Accordingly, it was confirmed that the in vitro activity of the fusion protein including the FGF21 mutant protein, in which the 19^th amino acid was substituted with tyrosine, was increased compared to that of the wild-type FGF21.

Experimental Example 2-2. Experimental results of H05, H09, H11 and HyC

For the evaluation of the in vitro activities of FGF21 mutant proteins and each of the linker structures, the in vitro activities of H05, H09, H11 and HyC proteins were measured in accordance with the above experimental method. As a result, it was confirmed that the in vitro activity of the H05 was most excellent. In case of the HyC, the activity measured via measurement of EC₅₀ value was excellent, but the E_max value was slightly low.

Experimental Example 2-3. Experimental results of H05 and H40

For the evaluation of the activities of fusion proteins including the wild-type FGF21 protein depending on the types of hybrid Fc, the activities of H05 and H40 were measured. As a result, it was confirmed that there was no significant difference in in vitro activity between the two materials.

Experimental Example 2-4. Experimental results of H05 and M09

For the measurement of the activities of fusion proteins depending on the presence/absence of a mutation in FGF21, the in vitro activities of H05 and M09 were evaluated. As a result, it was confirmed that the M09 showed an increased in vitro activity compared to that of H05. That is, it was found that the fusion protein including the mutant protein of FGF21 exhibits superior activity to the fusion protein including the wild-type FGF21 protein.

Experimental Example 2-5. Experimental results of M09 and F09

For the evaluation of the in vitro activities of the mutant, in which the 19^th amino acid of the wild-type FGF21 was substituted with tyrosine, depending on the hybrid Fc, the in vitro activities of M09 and F09 were measured. As a result, it was confirmed that there was no significant difference in in vitro activity between the two materials. Accordingly, it was found that the activity of the FGF21 mutant may be significantly influenced by the position of the FGF21 mutant, not by the type of Fc.

Experimental Example 3. Pharmacokinetic measurement of fusion proteins

Experimental Example 3-1. Experimental method for pharmacokinetic measurement

Six-week old male ICR mice purchased from Orient BIO (Korea) were partitioned into groups (n = 3/blood sampling time) to have a similar mean value of body weight one day before drug treatment, and subcutaneously administered once with a respective sample in an amount of 2 mg/kg. And then, their blood samples were collected at 1-, 4-, 8-, 12-, 24-, 48-, 72-, 96-, 144-, and 192 hours, respectively. The concentration of intact full length FGF21 in the blood was measured using an intact human FGF21 ELISA Kit (F1231-K01, Eagle Biosciences, USA), which has an immuno-reactivity to the N-terminus and C-terminus of FGF21. The blood concentrations of the samples collected until 192 hours after the subcutaneous injection into the mice were measured.

Experimental Example 3-2. Measurement result of pharmacokinetic activity

3-2-1. Experimental results of N00 and N12

For the evaluation of the pharmacokinetics of fusion proteins including FGF21 depending on the mutation on the 19^th amino acid of FGF21, experiments were performed using N00 and N12. The blood concentrations of N00 and N12 until 192 hours after the subcutaneous injection into the mice are shown in FIG. 3. N00 showed a high value of blood concentration depending on time and about 2.4-fold increase of a value of the areas under the curve (AUC) of blood concentration compared to N12. The two materials showed similar half-lives; i.e., 20.9 hours for N00 and 18.8 hours for N12.

3-2-2. Experimental results of H05, H09, H11 and HyC

For the evaluation of pharmacokinetics of FGF21 mutant proteins and each of the linker structures, pharmacokinetics of H05, H09, H11 and HyC proteins were measured in accordance with the method described above. The blood concentrations of H05, H09, H11 and HyC proteins depending on time after the subcutaneous injection are shown in FIG. 6. H05 and H11 showed similar levels of the areas under the curve of blood concentration, which represents the level of drug exposure; H09 showed a value reduced by about 40% compared to that of H05; and HyC showed the lowest value of the areas under the curve of blood concentration due to rapid loss of the drug. Additionally, the half-lives of each of the materials were 18.3 hours for H05, 19.0 hours for H09, 20.9 hours for H11, and 5.7 hours for HyC, respectively. That is, they showed similar half-lives except HyC.

3-2-3. Experimental results of H05 and H40

For the evaluation of the pharmacokinetics of fusion proteins including the wild-type FGF21 protein depending on the types of hybrid Fc, pharmacokinetics of H05 and H40 were measured. The blood concentrations of H05 and H40 depending on time after subcutaneous injection in mice are shown in FIG. 11. H40 showed the areas under the curve of blood concentration with about 1.6-fold increase compared to that of H05, and the two materials showed similar levels of half-lives; i.e., 18.3 hours for H05 and 18.7 hours for H40.

3-2-4. Experimental results of H05 and M09

For the measurement of pharmacokinetics of fusion proteins depending on the presence/absence of a mutation in FGF21, the pharmacokinetics of H05 and M09 was evaluated. Referring to the values of the areas under the curve of blood glucose concentration from the day of drug treatment (the 0^th day) to the 7^th day, similar hypoglycemic effects were exhibited at administration dosages of 10 mg/kg of H05 and 3 mg/kg of M09. Thus, it is suggested that M09 has superior hypoglycemic effect to H05 about 3 times. The group administered with M09 at a dosage of 10 mg/kg also showed an improved effect of inhibiting body weight increase compared to that of the H05 group. Specifically, on the 4^th day, M09 at a dosage of 10 mg/kg showed a significant inhibitory effect against body weight increase. Accordingly, it was confirmed that M09 is a long-acting FGF21 protein showing excellent anti-diabetic effect and inhibitory effect against body weight increase, compared to H05.

3-2-5. Experimental results of M09 and F09

For the measurement of pharmacokinetics of an FGF21 mutant, in which the 19^th amino acid of the wild-type FGF21 was substituted with tyrosine, depending on the hybrid Fc, the pharmacokinetics of M09 and F09 were measured. The concentrations of M09 and F09 in the blood after the subcutaneous injection in mice are shown in FIG. 14A. F09 showed the areas under the curve of blood concentration with about 1.6-fold increase compared to that of M09, and the half-lives of the two materials were 15.6 hours for M09 and 20.9 hours for F09, respectively.

Experimental Example 4. Activity evaluation of fusion proteins in ob/ob mice

Experimental Example 4-1. Experimental method for evaluating activities anti-diabetic efficacy in ob/ob mice

The ob/ob mice are those which are characterized by having hyperglycemia, insulin resistance, hyperphagia, fatty liver, and obesity due to genetic deficiency in leptin, and is widely used for the study of type 2 diabetes. Male ob/ob mice (Harlan, USA) and the age-matched lean mice of the control group were purchased from Raonbio (Korea). These mice were 5- to 6-week old at the time of arrival, and 8- to 9-week old at the time of drug treatment after 3 weeks of adaptation. The mice were partitioned into groups (n=8/group) to have a similar mean value of body weight and caudal blood glucose levels one day before the drug treatment (the 0^th day), and the samples were subcutaneously administered once according to each of their respective dosage. In particular, Dulbecco's phosphate buffered saline (DPBS, Gibco, USA) was administered as the vehicle treatment, and the glucose concentration in the blood was measured using a glucose meter, GlucoDr (All Medicus, Korea). The non-fasting glucose levels until the 7^th day after the administration were measured. Additionally, the values of the areas under the curve of blood glucose from the 0^th day to the 7^th day were calculated.

Experimental Example 4-2. Result of anti-diabetic efficacy evaluation in ob/ob mice

4-2-1. Experimental results of N00 and N12

In order to identify the in vivo effects of the fusion proteins including the FGF21 depending on the mutation on the 19^th amino acid of FGF21, experiments were performed using N00 and N12. Referring to the graph of FIG. 4A, which illustrates the non-fasting blood glucose levels until the 7^th day after the administration, the N00 (SEQ ID NO: 06) showed excellent glucose lowering effect at a dosage of 3 mg/kg or higher, whereas N12 (SEQ ID NO: 18) showed an excellent effect of controlling blood glucose levels even at a dosage of 1 mg/kg, and also lowered the blood glucose levels to a level equal to that of normal control group. Referring to FIG. 4B, which illustrates the values of the areas under the curve of blood glucose concentration from the day of drug treatment (the 0^th day) to the 7^th day, the dosage of 1 mg/kg of N12 and 3 mg/kg of N00 showed a similar glucose lowering effect, and thus, it is suggested that N12 has superior effect to N00 about 3 times. Further, the group administered with N12 showed an potent lowering inhibitory effect against body weight increase compared to that of the group administered with N00 at an equal dosage. In comparison with the effect on the 4^th day after the administration, 1 mg/kg of N12 and 3 mg/kg of N00 showed a similar level of inhibitory effects against body weight increase. Accordingly, it was confirmed that N12 is a mutant having a stronger anti-diabetic effect than N00.

That is, it was confirmed that the mutant, N12, has not only an excellent activity in the in vitro evaluation as compared to that of N00, but also a higher anti-diabetic effect and a higher inhibitory effect against body weight increase at an equal dosage in a mouse model compared to those of N00.

4-2-2. Experimental results of H05, H09, H11 and HyC

In order to confirm the in vivo effects of FGF21 mutant proteins and each of the linker structures, experiments were performed on H05, H09, H11 and HyC proteins in accordance with the method described above. Referring to FIG. 7A, which illustrates the values of the areas under the curve of blood glucose concentration from the day of administration (the 0^th day) to the 7^th day, the groups administered with H05 and H11, excluding H09, showed a glucose reducing effect in a dose-dependent manner. Regarding the inhibitory effect against body weight increase, the groups administered with H05 and H11 at a dosage of 10 mg/kg showed an excellent inhibitory effect (FIG. 7B).

4-2-3. Experimental results of H05 and H40

In order to confirm the in vivo effects of fusion proteins including the wild-type FGF21 protein depending on the types of hybrid Fc, experiments were performed on H05 and H40. According to each dosage, H05 (SEQ ID NO: 34) and H40 (SEQ ID NO: 38) were subcutaneously administered once. Referring to FIG. 12A, which shows a graph illustrating the non-fasting blood glucose levels until the 7^th day after the administration, H05 showed an excellent glucose lowering effect at a dosage of 10 mg/kg or higher, whereas H40, which showed an improved in vivo exposure value compared to that of H05 in a pharmacokinetic test, showed an excellent effect of controlling blood glucose levels even at a dosage of 3 mg/kg.

Referring to FIG. 12B, which illustrates the values of the areas under the curve of blood glucose concentration from the day of administration (the 0^th day) to the 7^th day, the administration of H05 at a dosage of 10 mg/kg and H40 at a dosage of 3 mg/kg showed similar glucose lowering effects, thus suggesting that H40 has approximately 3-fold potent effect compared to that of H05. Regarding the inhibitory effect against body weight increase, the group administered with H40 also showed an improved effect at a dosage of 10 mg/kg compared to that of H05. In comparison with the effect on the 4^th day after the administration, the group administered with H40 at a dosage of 3 mg/kg showed a higher inhibitory effect against body weight increase compared to the group administered with H05 at a dosage of 10 mg/kg (FIGS. 12C and 12D). Accordingly, H40 is a long-acting FGF21 protein which shows an excellent anti-diabetic effect and an improved inhibitory effect against body weight increase compared to that of H05.

That is, in the evaluation of H05 and H40, which link FGF21 and a hybrid Fc, the two materials showed similar activities in the in vitro evaluation. However, as shown in the result of pharmacokinetics in mice, H40 showed approximately a 1.6-fold increase in the value of the area under the curve compared to that of H05, and showed an improved glucose lowering effect and an improved inhibitory effect against body weight increase, even in a diabetic mouse model, ob/ob, compared to that of H05 at an equal dosage.

4-2-4. Experimental results of M09 and F09

In order to identify the in vivo effect of a mutant where the 19^th amino acid of the wild-type FGF21 was substituted with tyrosine depending on the hybrid Fc, experiments were performed on M09 and F09. According to each dosage, M09 (SEQ ID NO: 39) and F09 (SEQ ID NO: 40) were subcutaneously administered once. Referring to the graph of FIG. 15A, which illustrates the non-fasting blood glucose levels until the 7^th day after the administration, both materials showed excellent hypoglycemic effects at dosages of 3 mg/kg and 10 mg/kg, and in particular, showed blood glucose levels equal to the level of the normal control group at dosage of 10 mg/kg. F09 showed a good hypoglycemic effect in the group administered with a low dosage of 0.3 mg/kg, and this showed a blood glucose profile similar to that of the group administered with M09 at a dosage of 3 mg/kg. Referring to FIG. 15B, which illustrates the values of the areas under the curve of blood glucose from the day of drug treatment (the 0^th day) to the 7^th day, the administration of F09 at a dosage of 0.3 mg/kg and the administration of M09 at a dosage of 3 mg/kg showed similar hypoglycemic effects. Thus, it was confirmed that F09 has higher anti-diabetic effect in a low dosage, compared to that of M09.

Experimental Example 5. Evaluation of activity of fusion proteins in db/db mice

Experimental Example 5-1. Experimental method of evaluating activities in db/db mice

The anti-diabetic effect and the inhibitory effect against body weight increase of the samples including the fusion proteins were evaluated in another diabetic mouse model, i.e., db/db mice. The db/db mice are those characterized by having hyperglycemia, insulin resistance, hyperphagia, fatty liver, and obesity due to genetic deficiency in a leptin receptor, and is widely used for the study of type 2 diabetes, along with ob/ob mice. Six-week old male db/db mice (SLC, Japan) and the age-matched lean mice of the control group were purchased from Central Lab. Animal Inc. (Korea). These mice were 9-week old at the time of drug treatment after 3 weeks of adaptation. The mice were partitioned into groups (n=8/group) to have a similar mean value of body weight and caudal blood glucose levels one day before the drug treatment (the 0^th day), and the samples were subcutaneously administered once or twice (on the 0^th day and the 4^th day) according to each of their respective dosage. The graph of the non-fasting glucose levels and the values of the areas under the curve of glucose concentration until the 7^th day after the administration were measured.

Experimental Example 5-2. Result of activity evaluation in db/db mice

In order to measure the activity of F09 in db/db mice, the activity of F09 was measured in accordance with the method described above. Referring to the graph of FIG. 17A, which illustrates the non-fasting blood glucose levels until the 7^th day after the administration and the FIG. 17B, which illustrates the values of the areas under the curve of glucose concentration, glucose lowering effects were exhibited depending on the dosage of F09, and the group administered twice per week, compared to the group administered once, showed an excellent hypoglycemic effect revealing a value close to the blood glucose levels of normal mice on the 4^th day after the administration and thereafter. Further, regarding the inhibition of body weight increase, the F09 administration showed an inhibitory effect although it was not in a dose-dependent manner, and the group administered twice per week showed the highest inhibitory effect (FIGS. 17C and 17D). This experiment confirmed that the anti-diabetic effect and the inhibitory effect against body weight increase of F09 were also shown in a different diabetic mouse model, i.e., db/db mice.

Experimental Example 6. Pharmacokinetic study of fusion proteins in rats

In order to compare pharmacokinetic profile of the fusion proteins including a mutant where the 19^th amino acid of the wild-type FGF21 was substituted with tyrosine, the study was performed in rats. One day before the administration, male rats (Orient BIO, Korea) partitioned into groups (n=3/group) according to the mean value of body weight, were subcutaneously administered once with M09 (SEQ ID NO: 39) and F09 (SEQ ID NO: 40) at a dosage of 1 mg/kg, respectively, and the blood samples were collected at 1-, 4-, 8-, 12-, 24-, 48-, 72-, 96-, 144-, and 192 hours, respectively. FIG. 14B shows the concentrations of M09 and F09 in the blood depending on time after the subcutaneous injection. Similar to the pharmacokinetic results in mice, F09 showed the area under the curve of blood concentration with 1.4-fold increase compared to that of M09, and the half-lives of the two materials were 15.0 hours for M09 and 17.8 hours for F09.

Experimental Example 7. Evaluation of anti-obesity effect of fusion proteins in diet-induced obese mice

The body weight-reducing effects of M09 and F09 including an FGF21 mutant protein were evaluated in diet-induced obese mice. For the diet-induced obesity, C57BL/6J mice were purchased from Central Lab. Animal Inc. and fed in a high-fat diet containing 60 kcal % fat for about 8 to 12 weeks to prepare an obesity mouse model. One day before the administration, the mice were partitioned into groups (n=8/group) according to the mean value of body weight, and then subcutaneously administered with a test material once or at intervals of once per week for two weeks according to each dosage.

Regarding the body weight-reducing effects on the 7^th day and the 14^th day after the administration, both of the two materials reduced body weight in a dose-dependent manner. For single administration, F09 showed an excellent body weight loss effect at a dosage of 10 mg/kg and 30 mg/kg, compared to the group administered with M09 at an equal dosage. Further, the group administered with F09 twice at intervals of once a week at a dose of 10 mg/kg showed the highest body weight-reducing effect compared to all other administered groups including the group repeatedly administered with M09 at an equal dosage (FIGS. 16A and 16B). Accordingly, F09 is a long-acting FGF21 mutant showing an excellent anti-obesity effect compared to that of M09.

That is, in the evaluation of M09 and F09, which link a FGF21 mutant and a hybrid Fc, the two materials showed similar in vitro activities. However, in the pharmacokinetic test in mice and rats, F09 showed an improved value of the area under the curve of blood concentration, compared to that of M09. In addition, in the comparative evaluation of the effect in ob/ob mice, and diet-induced obese mice, F09 showed superior glucose lowering and body weight loss effect, compared to that of M09.

Experimental Example 8. Evaluation of stability of fusion proteins

Experimental Example 8-1. Experimental method of evaluating stability

In order to measure the amount of the protein aggregates at the initial stage of the samples, % high molecular weight aggregates (%HMW) were measured using a size-exclusion chromatography (SEC-HPLC) method. For the SEC-HPLC method, TosoHaas model TSK-GEL G3000SW_XL column was used. The column was equilibrated by flowing a buffer solution (1X PBS, 1 mM EDTA, pH 7.4) at a flow rate of 1 mL/min thereto. The M09 and F09 protein stock solutions were concentrated to a target concentration of 20 mg/mL or more at 3,000 rpm, 4℃ using a 30,000 MW cut-off centrifugation filter.

After the measurement of the concentration of each sample by BCA quantitative analysis, the samples were diluted with the buffer solution (1X PBS, 1 mM EDTA, pH 7.4) to a final concentration of 20 mg/mL. In order to measure the initial %HMW of M09 and F09, 20 mg/mL of the samples were diluted with the buffer solution (1X PBS, 1 mM EDTA, pH 7.4) to a final concentration of 0.5 mg/mL, and each sample in an amount of 100 μL was injected into the SEC-HPLC column for analysis. For the stability evaluation of each of the samples, %HMW of the samples were measured using the SEC-HPLC method on the 1^st-, the 2^nd, and the 4^th week while storing them at 4℃ and 25℃ for four weeks. The samples stored for 1-, 2-, and 4 weeks were analyzed with the zero-hour sample (initial stage).

Experimental Example 8-2. Evaluation of stability of N09 and F09

As a result of stability measurement of M09 and F09 in accordance with the experimental method described above, the analysis results of zero-hour sample (initial stage) and 1-, 2-, and 4 week-stored samples of M09 and F09 are summarized in Table 4 below. The amount of %HMW at zero hour was 2.27% for M09, but it was not observed in F09. At a time-point of more than 4 weeks, the amount of %HMW was 3.70% for M09 and 1.31% for F09. F09 was shown to have a lower HMW rate at the initial stage and at a time-point more than 4 weeks.

Stability of M09 and F09 for 4 weeks at concentration of 20 mg/mL (%HMW)

Week	Initial Stage	1 Week		2 Weeks		4 Weeks
Temp.		4℃	25℃	4℃	25℃	4℃	25℃
M09	2.27	2.19	2.32	2.53	2.50	3.70	3.90
F09	0.00	1.07	1.27	1.40	1.45	1.31	1.45

Claims (15)

1. A fusion protein comprising an Fc region of an immunoglobulin and an FGF21 mutant protein where arginine, which is the 19^th amino acid of an amino acid sequence represented by SEQ ID NO: 1, is substituted with a different amino acid.
2. The fusion protein of claim 1, wherein the FGF21 mutant protein has a substitution at the 19^th amino acid of the amino acid sequence represented by SEQ ID NO: 1 from arginine into tyrosine.
3. The fusion protein of claim 1, wherein the FGF21 mutant protein is linked to the Fc region of the immunoglobulin via a linker.
4. The fusion protein of claim 3, wherein the linker is a peptide consisting of 10 to 20 amino acid residues including glycine- and serine residues.
5. The fusion protein of claim 4, wherein the linker is GGGGSGGGGSGGGGS (SEQ ID NO: 2) or GGGGSGGGGSGGGGSA (SEQ ID NO: 3).
6. The fusion protein of claim 1, wherein the Fc region of the immunoglobulin is any one of IgG1, IgG2, IgG3, IgG4 and IgD regions, or a hybrid Fc, which is a combination thereof.
7. The fusion protein of claim 6, wherein the hybrid Fc comprises the IgG4 region and the IgD region.
8. The fusion protein of claim 1, wherein the fusion protein has an amino acid sequence represented by SEQ ID NO: 18.
9. The fusion protein of claim 1, wherein the fusion protein has an amino acid sequence represented by SEQ ID NO: 39.
10. The fusion protein of claim 1, wherein the fusion protein has an amino acid sequence represented by SEQ ID NO: 40.
11. A pharmaceutical composition comprising the fusion protein according to any one of claims 1 to 10 for treating diabetes, obesity, dyslipidemia or metabolic syndrome.
12. A method of treating or preventing diabetes, obesity, dyslipidemia or metabolic syndrome comprising administering the fusion protein according to any one of claims 1 to 10 to a subject in need of treatment.
13. An isolated nucleic acid molecule encoding the fusion protein according to any one of claims 1 to 10.
14. An expression vector comprising the nucleic acid of claim 13.
15. A host cell comprising the expression vector of claim 14.

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