Patent Description:
Interleukin-<NUM> (IL-<NUM>) is produced when lymphocyte proliferation is stimulated by a mitogen such as phytohemagglutinin (PHA). The IL-<NUM> produced by lymphocytes acts on cells with IL-<NUM> receptors on their surface, causing the cells to proliferate and exert the biological functions thereof. The research on this factor and its receptors has become increasingly intensive recently, and it has been found that the factor plays an important role in cellular immunity, humoral immunity and immunomodulation, and especially its role and clinical significance in tumor immunotherapy has drawn great attention. IL-<NUM> was approved for the treatment of renal cell carcinoma and metastatic melanoma many years ago, but the application of commercial drugs has been limited mainly due to the following: (<NUM>) low effective rate: the effective rate of IL-<NUM> used alone can only reach about <NUM>-<NUM>%; (<NUM>) two-sided functions of IL-<NUM>: a low dose of IL-<NUM> promotes the proliferation of regulatory T cells and causes immunosuppression, and how to balance the two functions remains to be solved; (<NUM>) short half-life: the half-life is only a few minutes, and administration at a large dose is a must for sustained effect; (<NUM>) severe adverse reaction: the over-activated immune system may attack visceral organs and thus cause organ failure, and the dose window is relatively narrow. In order to improve the therapeutic effect of IL-<NUM> and reduce its adverse reaction, various combined regimens have been tried, such as that of IL-<NUM> and interferon, IL-<NUM> and lymphokine-activated killer (LAK) cell therapy, and IL-<NUM> and chemotherapy, but none of these is satisfactory.

In recent years, studies have found that the addition of chemical modification to the normal IL-<NUM> molecule can maintain the effect of IL-<NUM> while reducing the use concentration and side effects as well. For example, NKTR-<NUM> developed by Nektar has lower side effects and better specificity, and can more efficiently activate the immune system. Specifically, <NUM> polyethylene glycol (PEG) modifications are added to the IL-<NUM> molecule to form an inactive medicament; after injection into a tumor patient, the <NUM> PEG modifications will gradually be shed to form the active <NUM>-PEG and <NUM>-PEG.

To address toxicity of IL-<NUM>, certain conjugates of IL-<NUM> have also been proposed; for example, <CIT> discloses a conjugate of an IL-<NUM> moiety with one or more non-peptide water-soluble polymers and a method for preparing the conjugate.

A form of PEGylated IL-<NUM> is designed in the non-patent literature "Relationship of Effective Molecular Size to Systemic Clearance in Rats of Recombinant Interleukin-<NUM> Chemically Modified with Water-soluble Polymers" in which a PEG molecule is conjugated to the primary amine of IL-<NUM> to form a protein heterogeneous mixture containing <NUM> IL-<NUM> molecule and <NUM> PEG molecules. This study found that the covalent attachment of the hydrophilic polymer polyethylene glycol can increase the solubility of IL-<NUM> and reduce the plasma clearance, thereby improving its anti-tumor capability <CIT> discloses mixtures of PEG-IL2. In addition, it describes ion exhcange chromatography or reverse-phase chromatography as purification methods for the obtention of the pegylated IL2 variants.

However, in the prior art, there are neither methods for obtaining high-purity disubstituted PEGylated interleukin <NUM> nor reports about high-purity PEGylated interleukin <NUM> and uses thereof.

The invention is defined in claims <NUM>-<NUM>.

The present invention provides a preparation method for the mixture of PEGylated interleukin <NUM> comprises the following specific steps:.

Preferably, a content of a disubstituted PEGylated interleukin <NUM> in the components of the mixture of PEGylated interleukin <NUM> is greater than <NUM>%,further preferably greater than <NUM>%, particularly preferably greater than <NUM>%.

Preferably, the mixture of PEGylated interleukin <NUM> further comprises a trisubstituted PEGylated interleukin <NUM> and/or a monosubstituted PEGylated interleukin <NUM>.

Preferably, a content of the trisubstituted PEGylated interleukin <NUM> in the mixture of PEGylated interleukin <NUM> is less than <NUM>%, further preferably less than <NUM>%, particularly preferably less than <NUM>%.

Preferably, a content of the monosubstituted PEGylated interleukin <NUM> in the mixture of PEGylated interleukin <NUM> is less than <NUM>%, further preferably less than <NUM>%, particularly preferably less than <NUM>%.

Preferably, the PEG is a linear or branched PEG (<NUM>-<NUM> arm branched PEG), including linear PEG, double-ended PEG, <NUM>-arm branched PEG, <NUM>-arm branched PEG, <NUM>-arm branched PEG, <NUM>-arm branched PEG, or the like.

Preferably, the PEG has a molecular weight of <NUM>-<NUM> KDa, such as <NUM>-<NUM> KDa (specifically <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or <NUM> KDa), <NUM>-<NUM> KDa (specifically <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or <NUM> KDa) or <NUM>-<NUM> KDa (specifically <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or <NUM> KDa).

Preferably, the interleukin <NUM> (IL-<NUM>) includes a mammalian wild-type interleukin <NUM> (IL-<NUM>) and active variants.

More preferably, the active variants of interleukin <NUM> (IL-<NUM>) include glycosylated variants or non-glycosylated variants; particularly preferably, the non-glycosylated variants of the interleukin include IL-<NUM> phosphorylated variants and IL-<NUM> polypeptide molecule fusion or polymeric variants.

Preferably, the PEG can be linked to the interleukin <NUM> through a hydrolytic bond, such as an amide bond, a urethane bond, an amine bond, a thioether bond, or an urea bond.

The present invention also provides a preparation method for the disubstituted PEGylated interleukin <NUM> comprises:.

Preferably, the PEG in the step (<NUM>) may have a molecular weight of <NUM>-<NUM> KDa, such as <NUM>-<NUM> KDa (specifically <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or <NUM> KDa), <NUM>-<NUM> KDa (specifically <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or <NUM> KDa) or <NUM>-<NUM> KDa (specifically <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or <NUM> KDa). More preferably, the PEG in the step (<NUM>) has a molecular weight of <NUM> KDa.

Preferably, the PEG in the step (<NUM>) may be a linear or branched PEG (<NUM>-<NUM> arm branched PEG), including linear PEG, double-ended PEG, <NUM>-arm branched PEG, <NUM>-arm branched PEG, <NUM>-arm branched PEG, <NUM>-arm branched PEG, or the like. More preferably, the PEG in the step (<NUM>) is a linear single-chain PEG.

PEG in the step (<NUM>) is methoxy polyethylene glycol succinimidyl propionate.

In one embodiment of the present invention, the step (<NUM>) comprises: adding methoxy polyethylene glycol succinimidyl propionate and IL2 to a buffer and reacting at room temperature for <NUM>-<NUM>, preferably <NUM>-<NUM>.

Preferably, a flow rate of loading and elution for the gel chromatography filtration in the step (<NUM>) is <NUM>-<NUM>/min, further preferably <NUM>/min;
Preferably, the elution buffer for the gel chromatography filtration in the step (<NUM>) is an acetic acid solution and a sodium chloride solution, a concentration of the acetic acid solution is <NUM>-<NUM>, and a concentration of the sodium chloride solution is <NUM>-<NUM>; more preferably, the elution buffer for the gel chromatography filtration is <NUM> acetic acid solution and <NUM> the sodium chloride solution.

In one embodiment of the present invention, the step (<NUM>) comprises:.

Preferably, the step (<NUM>) comprises: loading a sample onto the α receptor affinity column, wherein the sample is the product obtained in the step (<NUM>); after the sample loading, eluting with an equilibration buffer, preferably until UV is stable, and collecting the flow-through peak; after washing, using an elution buffer instead to elute and collecting the elution peak.

Preferably, a flow rate of loading and elution in the step (<NUM>) is <NUM>-<NUM>/min, preferably <NUM>/min;
preferably, the equilibration buffer in the step (<NUM>) is a PBS solution with a concentration of <NUM>-<NUM>, and the elution buffer is a balanced salt solution with a concentration of <NUM>-<NUM>.

More preferably, the chromatographic column used in the receptor affinity chromatography in step (<NUM>) is an α receptor affinity column, the equilibration buffer is <NUM> PBS solution, and the elution buffer is <NUM> sodium acetate solution and <NUM> sodium chloride solution.

In one embodiment of the present invention, the step (<NUM>) comprises: after a <NUM> α receptor affinity column is installed, equilibrating the system until the UV curve is stable; loading a sample, wherein the sample is the product obtained in the step (<NUM>), and the flow rate is controlled at <NUM>/min; after the sample loading is completed, eluting with the equilibration buffer until UV is stable, and collecting the flow-through peak; after washing, using an elution buffer instead to elute a mixture of the PEGylated IL-<NUM> and collecting the elution peak.

Preferably, the step (<NUM>) comprises: loading one or two of the flow-through peak component and the elution peak component in the step (<NUM>) through a sample injection loop, using a washing buffer A1 instead, after the sample loading, for elution until UV is stable, and collecting a flow-through peak; after the washing is completed, using an elution buffer B1 instead for elution, and collecting an elution peak; after the collecting is completed, using an elution buffer A2 instead for elution, and collecting an elution peak; after the collecting is completed, using an elution buffer B2 instead for elution, and collecting an elution peak.

Preferably, the elution flow rate for the ion exchange separation in the step (<NUM>) is <NUM>-<NUM>/min, more preferably <NUM>/min;
In the ion exchange chromatography, the equilibration buffer is a NaAc solution, and the washing buffer A1 is a NaAc solution; the elution buffer B1 is a NaAc solution, and a conductivity is adjusted to <NUM>-<NUM>/cm; the elution buffer A2 is a NaAc solution, and the conductivity is adjusted to <NUM>-<NUM>/cm; the elution buffer B2 is a NaAc solution.

More preferably, in the ion exchange chromatography, the washing buffer A1 is <NUM> NaAc pH <NUM>, the elution buffer B1 is <NUM> NaAc pH <NUM>, and the conductivity is adjusted to <NUM>/cm; the elution buffer A2 is <NUM> NaAc pH <NUM>, and the conductivity is adjusted to <NUM>/cm with <NUM> NaCl; the elution buffer B2 is <NUM> NaAc pH <NUM> containing <NUM> NaCl.

Preferably, the elution peak for the elution buffer A2 is collected in the step (<NUM>), so as to obtain the components of the disubstituted PEGylated interleukin <NUM>.

Unless defined otherwise, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those skilled in the art to which the present invention relates, for example:.

Unless otherwise stated, the term "preventing" include reducing the risks of having, contracting or experiencing a disease, disorder, condition or state, the development and/or progression thereof, and/or symptoms thereof.

Unless otherwise stated, the terms "treatment" and "treating" include inhibiting, delaying, moderating, attenuating, limiting, alleviating, or causing the regression of a disease, disorder, condition or state, the development and/or progression thereof, and/or symptoms thereof.

Unless otherwise stated, the terms "comprise" "comprising" and "containing" are intended to represent "open" or "inclusive" language, such that they include the enumerated elements and also allow for the inclusion of additional, unmentioned elements.

In the figures, G1 is blank control group, G2 is IL-<NUM> group (<NUM>/kg), G3 is NKTR-<NUM> group (<NUM>/kg), G4 is sample No. <NUM> group (<NUM>/kg), and G5 is sample No. <NUM> group (<NUM>/kg).

The technical solutions in the examples of the present invention will be described clearly and completely below, and it is apparent that the examples described herein are only some examples of the present invention, but not all of them. Based on the examples of the present invention, all other examples obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

S1: <NUM> of methoxy polyethylene glycol succinimidyl propionate with a molecular weight of <NUM> (M-SPA-<NUM>) was weighed accurately and added into a <NUM> centrifuge tube;
S2: <NUM> of <NUM>/mL IL2 was added, and the resulting mixture was mixed gently until the PEG was completely dissolved;
S3: <NUM> of <NUM> PBS buffer (pH <NUM>) was then added, and the resulting mixture was mixed gently and left to stand at room temperature for reaction for <NUM>;
S4: the tube was slowly shaken at room temperature for <NUM>;
S5: the excess receptors were washed off with <NUM> column volumes of coupling buffer;
S6: a sample was taken and the content of each component in the reaction mixture was determined by HPLC, and the results are shown in <FIG> and Table <NUM>:.

The gel chromatography filtration was set as follows: mobile phase: <NUM> PBS, flow rate: <NUM>/min, chromatography column: superdex <NUM> increase <NUM>/<NUM> GL.

The separation steps were as follows: S1: the chromatography system was equilibrated until the UV curve was stable; S2: the elution peak was collected after the sample obtained in the Example <NUM> was loaded;.

S3: the collected components were concentrated by ultrafiltration and detected by HPLC, and the results are shown in <FIG> and Table <NUM>:.

The receptor column affinity chromatography was set as follows: mobile phase A: <NUM> PBS, pH <NUM>, mobile phase B: <NUM> HAc + <NUM> NaCl, flow rate: <NUM>/min, column: <NUM> α receptor affinity column, self-made.

The separation steps were as follows: S1: the chromatography system was equilibrated until the UV curve was stable; S2: the flow-through peak and the elution peak were collected after the sample obtained in the Example <NUM> was loaded.

The ion exchange separation chromatography was set as follows: mobile phase A1: <NUM> NaAc pH <NUM>, mobile phase B1: <NUM> NaAc pH <NUM>, conductivity adjusted to <NUM>/cm with <NUM> NaCl, mobile phase A2: <NUM> NaAc pH <NUM>, conductivity adjusted to <NUM>/cm with <NUM> NaCl, mobile phase B2: <NUM> NaAc pH <NUM> containing <NUM> NaCl, flow rate: <NUM>/min, column: CM FF <NUM>.

The separation steps were as follows: S1: the chromatography system was equilibrated until the UV curve was stable; S2: the flow-through/elution components separated in the Example <NUM> were each loaded through a sample injection loop; S3: elution was performed with the phase A1 until the UV was stable, and a flow-through peak was collected; S4: elution was performed with the phase B1 instead, and an elution peak was collected; S5: elution was performed with the phase A2 instead, and an elution peak was collected; S6: elution was performed with the phase B2 instead, and an elution peak was collected; S7: the collected components were detected for volume and concentration; S8: the HPLC detection was performed; S9: the collected components were concentrated by ultrafiltration and detected by SDS-PAGE.

Samples No. <NUM>, No. <NUM>, No. <NUM> and No. <NUM> were collected separately, concentrated and then subjected to affinity assay using a SPR system. The receptor proteins are an IL-2α receptor and an IL-2β receptor, and the test results are shown in Table <NUM>. The results showed that the 2PEG-IL-<NUM> prepared by the method described herein generated receptor selectivity and had stronger binding ability to the IL-2β receptor.

To assess the effect of the test drug 2PEG-IL-<NUM> on the level of p-Stat5 in female C57BL/<NUM> mice at different time points.

The test compound 2PEG-IL-<NUM> and the positive control drug NKTR214 were administrated separately, blood samples were taken at <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM>, and the p-Stat5 levels in the blood samples of female C57BL/<NUM> mice were determined by flow cytometry. The specific administration design is shown in Table <NUM>:.

The expression levels of p-Stat5 cells were analyzed using the analysis software that came with an Attune NxT flow cytometer, and the plotting and data analysis were performed using prism graphpad5.

The curves of p-Stat5 expression levels of the drugs in two groups at different time points are shown in <FIG>.

In this experiment, the drugs IL-sample <NUM> and NKTR214 were administered via tail vein injection in female C57BL/<NUM> mice, and the p-Stat5 levels at different time points were determined by flow cytometry. The results showed that the area under the curve was smaller for the 2PEG-IL-<NUM> group relative to the NKTR214 group, indicating that it results in lower expression and faster metabolic efficiency of p-Stat5 in mice.

In this experiment, p-Stat5 expression induced by the test drug 2PEG-IL-<NUM> is metabolized more rapidly relative to the positive drug in the NKTR214 group. The persistence of phosphorylation activation is significantly reduced compared to NKTR214.

In vivo experimental study on anti-tumor effect for B16-F10 subcutaneous tumors in C57BL/<NUM> mice.

To evaluate the growth of B16-F10 subcutaneous tumors in C57BL/<NUM> mice.

<NUM> mice/carrier group, <NUM> mice/treatment group, a total of <NUM> groups as shown in Table <NUM>:.

The mice were fed in BioDuro eco-boxes (Shanghai).

The mice were housed in ventilated cages with constant temperature and humidity and there were up to <NUM> animals in each cage.

B16F10 was incubated in a <NUM>% CO<NUM> incubator at <NUM> with RPMI-<NUM> supplemented with <NUM>% heat-inactivated FBS. The cells were subcultured <NUM> times a week. The cells had been harvested, counted and subcultured, and inoculated when the confluence was about <NUM>%.

When B16f10 reached the desired average size (<NUM>-<NUM><NUM>), <NUM> animals were enrolled to the efficacy study. The animals were randomized as follows according to tumor size by using block randomization in Excel. This ensured that all groups were comparable at baseline. <NUM> × <NUM> B16F10 cells suspended in <NUM>µL of PBS had been inoculated subcutaneously into the right flank.

All procedures related to animal handling, care and treatment in this study were performed according to guidelines approved by Institutional Animal Care and Use Committee (IACUC) of BioDuro and followed the guidelines of The Association for Assessment and Accreditation of Laboratory Animal Care (AAALAC, accreditation number <NUM>). In routine monitoring, the animals had been examined for any adverse effects of tumor growth and/or treatment on normal behavior, such as motility, food and water consumption (by observation only), and body weight gain/loss (the body weight was measured twice weekly during the pre-administration phase and daily during the administration phase), eye/hair matting, and any other abnormal effects, including tumor ulceration.

Tumor volume was measured in two dimensions twice weekly with a caliper, and the volume was expressed in mm<NUM> by the following formula: V = <NUM>. 5a × b<NUM>, where a and b are the long and short diameters of the tumor, respectively. The tumor volume was then used to calculate the T-C and T/C values. T-C was calculated, where T is the median time (in days) required for tumors in the treatment group to reach a predetermined size and C is the median time (in days) for tumors in the control group to reach the same size. The T/C value (in percent) is an indication of anti-tumor efficacy; T and C are the average volumes of the treatment and control groups, respectively, on a given day. The T-C value was calculated according to TV. T-C had been calculated with T as the median time (days) required for tumors in the treatment group to reach a predetermined size and C as the median time (days) for tumors in the control group to reach the same size. The tumor tissues were photographed and weighed at the end of the study.

The tumor tissues were collected at different time points, and after digestion and decomposition of the tumor tissues into individual cells, the cells were subjected to immunofluorescence staining with CD45, CD3, CD4, CD8, CD25 and FOXP3. The stained cells were counted with a flow cytometer and then the proportions of cells with different labels were calculated.

The laboratory animals in groups <NUM>, <NUM> and <NUM> showed significant weight loss; there were only <NUM> animals left in group <NUM> on day <NUM> after drug injection, and all of these animals were sacrificed on day <NUM>, so data for day <NUM> were missing. The curves of change in body weight of the animals in each group are shown in <FIG>.

The animals in groups <NUM>, <NUM>, <NUM> and <NUM> showed significant anti-tumor activity, and the curves of change in tumor volume are shown in <FIG>.

The proportions of different immune cells in tumor tissues were determined by FACS, and the curves of change in the proportion of CD4 T cells to T cells are shown in <FIG>.

The curves of change in the proportion of Treg cells to CD4 T cells in tumor tissues are shown in <FIG>.

The curves of change in the proportion of Th cells to CD4 T cells are shown in <FIG>.

The curves of change of CD8 T cells in tumor cells are shown in <FIG>.

The curves of change in the proportion of CD8/Treg in tumor tissues are shown in <FIG>.

The curves of change in double samples CD8 and PD-<NUM> T cells are shown in <FIG>.

In this experiment, the anti-tumor effect of PEG-IL-<NUM> was tested on B16F10 melanoma-bearing C57BL6 mice, the mechanism of anti-tumor activity of PEG-IL-<NUM> was also studied, and the changes in the content of different types of immune cells in tumor tissues at different stages were tested. The samples include IL2 (group <NUM>) and three PEG-IL-<NUM> components, including NKTR-<NUM> (group <NUM>), sample No. <NUM> (receptor column flow-through sample) and sample No. <NUM> (receptor column elution sample).

A stringent toxicity test was not performed in this experiment, but toxicity was observed generally from the body weight changes and deaths of the mice. The body weight changes showed that the body weight of animals in groups <NUM>, <NUM> and <NUM> clearly decreased first and then increased. This indicated that all the three PEG-IL-<NUM> were toxic. The animals in NKTR-<NUM> group were almost all dead by the second time point, indicating that NKTR-<NUM> was more toxic at a dose of <NUM>/kg.

According to the curves of change in tumor volume, IL-<NUM> and three PEG-IL2 showed significant anti-tumor activity, with NKTR-<NUM> showing the minimal tumor volume.

IL-<NUM> is an immune cell molecule that achieves the purpose of killing tumor cells by regulating the type and the number of immune cells. The manner in which PEG-IL-<NUM> inhibits tumors was explored by analyzing the number of different immune cells in tumors. In this experiment, the changes in the number of immune cells labeled with CD45, CD3, CD4, CD8, CD25 and FOXP3 were tested by flow cytometry.

It has been reported in the literature that NKTR-<NUM> is an IL-<NUM> coupled with <NUM> PEGs, and its mechanism is that receptor selectivity can be generated after PEG coupling, and it is more likely to bind to β receptor. The binding of NKTR-<NUM> to β receptor can increase the proliferation of CD8 cells and inhibit the differentiation of Treg cells, which results in a proportion of CD8/Treg being <NUM> times that for IL-<NUM>.

According to the results of this experiment, both NKTR-<NUM> and sample No. <NUM> showed significant effect of increasing the proportion of CD8/Treg, so it can be seen that the mechanism of anti-tumor killing of 2PEG-IL-<NUM> sample and that of NKTR-<NUM> should be the same.

A hydrolysis process is required for the NKTR-<NUM> product to exert drug efficacy, and 6PEG-IL-<NUM> is not effective unless it is degraded to 2PEG-IL-<NUM> or 1PEG-IL-<NUM>. The hydrolysis process is relatively long, and it has been reported in the literature that only <NUM> PEG can be degraded about every <NUM> hours at pH <NUM> and <NUM>, and <NUM> hours are needed for degrading from 6PEG-IL-<NUM> to 2PEG-IL-<NUM>. In contrast, the PEG-IL-<NUM> sample of the present invention does not require the degradation process, so the time for it to exert drug efficacy is earlier than that of NKTR-<NUM>.

Claim 1:
A preparation method for a mixture of PEGylated interleukin <NUM>, comprising the steps of:
(<NUM>) reacting PEG with IL-<NUM> to obtain a crude product of a PEGylated interleukin <NUM>;
(<NUM>) performing gel chromatography filtration to remove free interleukin <NUM> from the crude product;
(<NUM>) performing affinity chromatography on a product in the step (<NUM>) by means of an α receptor column, and collecting a flow-through peak component and an elution peak component; and
(<NUM>) performing ion exchange separation on the flow-through peak component and/or the elution peak component in the step (<NUM>), and collecting to obtain components of the mixture of PEGylated interleukin <NUM>.