Fc variants that extend antibody half-life

Medicilon's pharmacokinetics department offers the clients a broad spectrum of high quality of services in the areas of in vitro ADME, in vivo pharmacokinetics and bioanalysis services, ranging from small molecules to large molecules, such as protein and antibody. The animal species involved in our services are non-human primate, canine, mice, rat, rabbit and hamster. Meanwhile, non-human primate experimental platform and isotope platform for protein/antibody are certified by the Shanghai Government. Email:marketing@medicilon.com.cn Web:www.medicilon.com.

In one aspect, the present invention provides an antibody comprising a variant Fc region as compared to a parent Fc region, wherein the variant Fc region comprises a first mutation which is a serine at position 434 and a second mutation selected from the group: an isoleucine at position 311, a valine at position 311, an isoleucine at position 436, and a valine at position 436. In a further aspect, the antibody has increased serum half-life as compared to an antibody comprising the parent Fc region, wherein numbering is according to the EU index. In a still further aspect, the antibody has increased binding affinity to a human FcRn receptor as compared to an antibody comprising the parent Fc region, wherein numbering is according to the EU index.

In one embodiment, the present invention provides nucleic acids encoding any of the variant Fc regions described herein.

In a further embodiment, the present invention provides host cells comprising a nucleic acid encoding any of the variant Fc regions described herein.

In one aspect, the present invention provides methods of administering an antibody to a subject, where the antibody comprises a variant Fc region as compared to a parent Fc region, wherein the variant Fc region comprises a first mutation which is a serine at position 434 and a second mutation selected from the group: an isoleucine at position 311, a valine at position 311, an isoleucine at position 436, and a valine at position 436, where the antibody has increased serum half-life as compared to an antibody comprising the parent Fc region, and wherein numbering is according to the EU index.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1. Sequence alignments of human IgG constant heavy chains. Gray indicates differences from IgG1, and boxed residues indicate common allotypic variations in the human population.

FIG. 2. (SEQ ID NO: 1-6) Amino acid sequences of constant regions used in the invention.

FIG. 3. (SEQ ID NO: 7-8) Amino acid sequences of exemplary variant constant regions.

FIG. 4. (SEQ ID NO: 9-10) Amino acid sequences of VH and VL variable regions used in the invention.

FIG. 5. Relative VEGF binding by WT and select variant IgG1 anti-VEGF antibodies. The plot shows the Biacore response units (RU) at the end of the association phase for binding of antibody analyte to immobilized VEGF antigen. Anti-Her2 IgG1 antibody was used as a negative control.

FIG. 6. Biacore sensorgrams of WT and variant IgG1 antibodies to immobilized human FcRn at low (6.0) and high (7.4) pH.

FIG. 7. FcRn binding affinities of WT and select variant IgG1 antibodies to human FcRn at pH 6.0 as determined by Biacore. The graph shows a plot of the pseudo-affinity constant (Ka*), on a log scale.

FIG. 8. In vivo pharmacokinetics study of WT and variant antibodies in mFcRn−/−hFcRn+ mice. The graphs plot the serum concentration of antibody versus time after a single intravenous dose. FIG. 8 a shows data from one of the 4 studies carried out with IgG1 antibodies (Study 3), and FIG. 8 b shows data from a study carried out with IgG2 antibodies (Study 5).

FIG. 9. Fitted PK parameters from all in vivo PK studies carried out in mFcRn−/− hFcRn+ mice with variant and WT antibodies. n represents the number of mice per group, with Mean and standard deviation (SD) data provided for PK parameters. Half-Life represents the beta phase that characterizes elimination of antibody from serum. Cmax is the maximal observed serum concentration, AUC is the area under the concentration time curve, and clearance is the clearance of antibody from serum. Fold half-life is calculated as the half-life of variant antibody over that of the WT IgG1 or IgG2 parent within each study.

FIG. 10. Relative binding of variant IgG1 anti-VEGF antibodies to cynomolgus monkey and human FcRn as determined by Biacore. FIG. 10 a shows the data in tabular form. FIG. 10 b shows a plot of the data.

FIG. 11. In vivo pharmacokinetics of WT and variant antibodies in cynomolgus monkeys. The graphs plot the serum concentration of antibody versus time after a single intravenous dose.

FIG. 12. Fitted PK parameters from the in vivo PK study in cynomolgus monkeys with variant and WT antibodies. Parameters are as described in FIG. 9.

FIG. 13. Designed Fc variants. Variants are screened using the described methods in order to obtain modifications that extend the in vivo half-life of antibodies.

FIG. 14. Screen of engineered Fc variants for binding to human FcRn. The table shows the off-rate (koff) for binding of each variant to human FcRn at pH 6.0 by Biacore.

FIG. 15. Graph of koff for screened Fc variants (data plotted are from FIG. 14).

FIG. 16. Affinities of select variants for human FcRn at pH 6.0 based on a FcRn concentration series Biacore experiment. The data show the on and off kinetic rate constants (kon and koff respectively), and the association and dissociation equilibrium constants (KA and KD respectively), as well as the fold improvement in KD and koff relative to WT IgG1 and IgG1/2 N434S.

FIG. 17. Plot off affinities of select variants for human FcRn at pH 6.0 as determined by Biacore. Values are plotted from FIG. 16.

FIG. 18. Plot off affinities of select variants for human FcRn at pH 6.0 as determined by Biacore. Values are plotted from FIG. 16.

FIG. 19. Designed single variants

FIG. 20. Designed combination variants

FIG. 21. Affinities of select variants for human FcRn at pH 6.0 based on a FcRn concentration series Biacore experiment. The data show the dissociation equilibrium constant KD, as well as the fold improvement in KD relative to the IgG1/2 parent.

FIG. 22. Plot off affinities of select variants for human FcRn at pH 6.0 as determined by Biacore. Values are plotted from FIG. 21.

FIG. 23. In vivo pharmacokinetics of IgG1/2 variant antibodies in mFcRn−/−hFcRn+ mice. The graphs plot the serum concentration of antibody versus time after a single intravenous dose.

FIG. 24. Fitted half-lives (t½) from the PK study in hFcRn+ mice. n=number of mice, columns n1-n5 show the half-lives of the individual mice in each group, and the average half-life and standard deviation are shown in the last two columns.

FIG. 25. Scatter plot of half-life results from PK study in hFcRn+ mice. Data are plotted from FIG. 24. Each dot represents the t½ of an individual mouse within each variant group, and the line indicates the average.