Methods for increasing efficacy of FOLR1 cancer therapy

1. A method for treating ovarian cancer comprising administering a therapeutically effective dose of an anti-Folate Receptor 1 (FOLR1) immunoconjugate to a human subject having ovarian cancer; wherein a FOLR1 staining intensity score of 2 or greater has been detected in greater than 75% of the cells in a tumor sample from the human subject using an immunohistochemistry (IHC) detection method that distinguishes between staining intensity and staining uniformity in a FOLR1 expressing cancer sample as compared to staining intensity and staining uniformity in one or more reference samples; wherein the IHC detection method can distinguish between different levels of FOLR1 staining intensity; and

wherein the anti-FOLR1 immunoconjugate has the formula (A)-(L)-(C), wherein:

(A) comprises an antibody or antigen binding fragment thereof comprising: (a) a heavy chain CDR1 comprising the amino acid sequence GYFMN (SEQ ID NO:6); a heavy chain CDR2 comprising the amino acid sequence RIHPYDGDTFYNQKFQG (SEQ ID NO:7); and a heavy chain CDR3 comprising the amino acid sequence YDGSRAMDY (SEQ ID NO:8); and (b) a light chain CDR1 comprising the amino acid sequence KASQSVSFAGTSLMH (SEQ ID NO:9); a light chain CDR2 comprising the amino acid sequence RASNLEA (SEQ ID NO:10); and a light chain CDR3 comprising the amino acid sequence QQSREYPYT (SEQ ID NO:11),

(L) comprises the linker N-succinimidyl 4-(2-pyridyldithio)-2-sulfobutanoate (sulfo-SPDB), and

(C) comprises the cytotoxic agent N(2′)-deacetyl-N(2′)-(4-mercapto-4-methyl-1-oxopentyl)-maytansine (DM4), and

wherein the linker (L) links (A) to (C).

2. The method of claim 1 , wherein the antibody or antigen binding fragment thereof of the immunoconjugate comprises a heavy chain variable domain comprising the amino acid sequence of SEQ ID NO: 3 and a light chain variable domain comprising the amino acid sequence of SEQ ID NO: 4 or 5.

3. The method of claim 1 , wherein the antibody or antigen binding fragment thereof of the immunoconjugate comprises (i) a heavy chain comprising the same amino acid sequence as the amino acid sequence of the heavy chain encoded by the plasmid deposited with the American Type Culture Collection (ATCC) as PTA-10772 and (ii) a light chain comprising the same amino acid sequence as the amino acid sequence of the light chain encoded by the plasmid deposited with the ATCC as PTA-10773 or PTA-10774.

4. The method of claim 1 , further comprising detecting FOLR1 expression in the tumor sample from the human subject using the IHC detection method prior to administering the therapeutically effective dose of the anti-FOLR1 immunoconjugate to the human subject having cancer.

5. The method of claim 1 , wherein the IHC detection method produces a range of staining intensity for samples having weak FOLR1 expression, moderate FOLR1 expression, or strong FOLR1 expression.

6. The method of claim 1 , wherein the tumor sample is a formalin fixed paraffin embedded sample.

7. The method of claim 1 , wherein the reference sample is a negative reference sample.

8. The method of claim 1 , wherein the reference sample comprises cells, cell pellets, or tissue.

9. The method of claim 1 , wherein the IHC detection method comprises detecting FOLR1 expression with an antibody or antigen binding fragment thereof that specifically binds FOLR1, wherein the antibody or antigen binding fragment thereof for detecting FOLR1 expression comprises (a) a heavy chain CDR1 comprising the amino acid sequence GYFMN (SEQ ID NO:6); a heavy chain CDR2 comprising the amino acid sequence RIHPYDGDTFYNQKFQG (SEQ ID NO:7); and a heavy chain CDR3 comprising the amino acid sequence YDGSRAMDY (SEQ ID NO:8); and (b) a light chain CDR1 comprising the amino acid sequence KASQSVSFAGTSLMH (SEQ ID NO:9); a light chain CDR2 comprising the amino acid sequence RASNLEA (SEQ ID NO:10); and a light chain CDR3 comprising the amino acid sequence QQSREYPYT (SEQ ID NO:11).

10. The method of claim 9 , wherein the antibody or antigen binding fragment thereof for detecting FOLR1 expression comprises a heavy chain variable domain comprising the amino acid sequence of SEQ ID NO: 3 and a light chain variable domain comprising the amino acid sequence of SEQ ID NO: 4 or 5.

11. The method of claim 1 , wherein the IHC detection method comprises detecting FOLR1 expression with an antibody that specifically binds FOLR1, wherein the antibody for detecting FOLR1 expression comprises (i) a heavy chain comprising the same amino acid sequence as the amino acid sequence of the heavy chain encoded by the plasmid deposited with the ATCC as PTA-10772 and (ii) a light chain comprising the same amino acid sequence as the amino acid sequence of the light chain encoded by the plasmid deposited with the ATCC as PTA-10773 or PTA-10774.

12. The method of claim 1 , wherein the IHC detection method comprises detecting FOLR1 expression with an antibody or antigen binding fragment thereof that specifically binds FOLR1, wherein the antibody or antigen binding fragment thereof for detecting FOLR1 expression is the antibody BN3.2.

13. The method of claim 1 , wherein the IHC detection method comprises detecting FOLR1 expression with an antibody or antigen binding fragment thereof that specifically binds FOLR1, wherein the antibody or antigen binding fragment thereof for detecting FOLR1 expression further comprises a detection reagent selected from the group consisting of: an enzyme, a fluorophore, a radioactive label, and a luminophore.

14. The method of claim 13 , wherein the detection reagent is selected from the group consisting of: biotin, digoxigenin, fluorescein, tritium, and rhodamine.

15. The method of claim 1 , wherein a staining intensity score of 3 or greater for FOLR1 expression has been detected in greater than 75% of cells of the tumor sample.

16. A method for treating ovarian cancer comprising:

(a) measuring the level of FOLR1 expression in a tumor tissue sample obtained from a tumor of a human subject having ovarian cancer using an IHC detection method that distinguishes between staining intensity and staining uniformity in the FOLR1 expressing tumor tissue sample as compared to staining intensity and staining uniformity in a reference sample; wherein the IHC detection method can distinguish between different levels of FOLR1 staining intensity;

(b) determining a FOLR1 expression score for the tumor tissue sample based on the level of FOLR1 staining intensity and staining uniformity in the tumor tissue sample;

(c) comparing the FOLR1 expression score for the tumor tissue sample determined in step (b) to a reference FOLR1 expression score determined by measuring FOLR1 staining intensity and staining uniformity in at least one reference sample, wherein a FOLR1 expression score for the tumor tissue sample determined in step (b) that is equal to or higher than the reference FOLR1 expression score identifies the tumor as being sensitive to treatment with an anti-FOLR1 immunoconjugate; and

(d) administering an anti-FOLR1 immunoconjugate to the human subject whose tumor is identified in step (c) as being sensitive to treatment with an anti-FOLR1 immunoconjugate;

wherein greater than 75% of cells of the tumor tissue sample have a staining intensity score of 2 or greater;

wherein the anti-FOLR1 immunoconjugate has the formula (A)-(L)-(C), wherein:

(A) comprises an antibody or antigen binding fragment thereof comprising: (a) a heavy chain CDR1 comprising the amino acid sequence GYFMN (SEQ ID NO:6); a heavy chain CDR2 comprising the amino acid sequence RIHPYDGDTFYNQKFQG (SEQ ID NO:7); and a heavy chain CDR3 comprising the amino acid sequence YDGSRAMDY (SEQ ID NO:8); and (b) a light chain CDR1 comprising the amino acid sequence KASQSVSFAGTSLMH (SEQ ID NO:9); a light chain CDR2 comprising the amino acid sequence RASNLEA (SEQ ID NO:10); and a light chain CDR3 comprising the amino acid sequence QQSREYPYT (SEQ ID NO:11),

(L) comprises the linker N-succinimidyl 4-(2-pyridyldithio)-2-sulfobutanoate (sulfo-SPDB), and

(C) comprises the cytotoxic agent N(2′)-deacetyl-N(2′)-(4-mercapto-4-methyl-1-oxopentyl)-maytansine (DM4), and

wherein the linker (L) links (A) to (C).

17. The method of claim 16 , wherein the antibody or antigen binding fragment thereof of the immunoconjugate comprises a heavy chain variable domain comprising the amino acid sequence of SEQ ID NO: 3 and a light chain variable domain comprising the amino acid sequence of SEQ ID NO: 4 or 5.

18. The method of claim 16 , wherein the antibody of the immunoconjugate comprises (i) a heavy chain comprising the same amino acid sequence as the amino acid sequence of the heavy chain encoded by the plasmid deposited with the ATCC as PTA-10772 and (ii) a light chain comprising the same amino acid sequence as the amino acid sequence of the light chain encoded by the plasmid deposited with the ATCC as PTA-10773 or PTA-10774.

19. The method of claim 16 , wherein the IHC detection method comprises detecting FOLR1 expression with an antibody or antigen binding fragment thereof that specifically binds FOLR1, wherein the antibody or antigen binding fragment thereof for detecting FOLR1 expression is the antibody BN3.2.

20. The method of claim 16 , wherein the reference sample comprises tissue, cells, or cell pellets.

21. The method of claim 16 , wherein greater than 75% of cells of the tumor tissue sample have a staining intensity score of 3 or greater for FOLR1 expression.

22. A method for treating ovarian cancer comprising:

(a) contacting a tumor tissue sample from a human subject having ovarian cancer with an antibody or antigen binding fragment thereof that specifically binds FOLR1, wherein the sample is formalin-fixed paraffin embedded;

(b) measuring the binding of the antibody or antigen binding fragment thereof to FOLR1 in the tumor tissue sample in step (a) using an IHC detection method that can distinguish between staining intensity and staining uniformity in the FOLR1 expressing tumor tissue sample as compared to staining intensity or staining uniformity in one or more reference samples;

(c) assigning a FOLR1 expression score to the tumor tissue sample after comparing the level of FOLR1 staining intensity and staining uniformity in the tumor tissue sample to one or more reference samples; and

(d) administering an anti-FOLR1 immunoconjugate to the human subject whose tumor tissue sample has greater than 75% of cells having a FOLR1 staining intensity score of 2 or greater;

wherein the anti-FOLR1 immunoconjugate has the formula (A)-(L)-(C), wherein:

(A) comprises an antibody or antigen binding fragment thereof comprising: (a) a heavy chain CDR1 comprising the amino acid sequence GYFMN (SEQ ID NO:6); a heavy chain CDR2 comprising the amino acid sequence RIHPYDGDTFYNQKFQG (SEQ ID NO:7); and a heavy chain CDR3 comprising the amino acid sequence YDGSRAMDY (SEQ ID NO:8);

and (b) a light chain CDR1 comprising the amino acid sequence KASQSVSFAGTSLMH (SEQ ID NO:9); a light chain CDR2 comprising the amino acid sequence RASNLEA (SEQ ID NO:10); and a light chain CDR3 comprising the amino acid sequence QQSREYPYT (SEQ ID NO:11),

(L) comprises the linker N-succinimidyl 4-(2-pyridyldithio)-2-sulfobutanoate (sulfo-SPDB), and

(C) comprises the cytotoxic agent N(2′)-deacetyl-N(2′)-(4-mercapto-4-methyl-1-oxopentyl)-maytansine (DM4), and

wherein the linker (L) links (A) to (C).

23. The method of claim 22 , wherein the antibody or antigen binding fragment thereof of the immunoconjugate comprises a heavy chain variable domain comprising the amino acid sequence of SEQ ID NO: 3 and a light chain variable domain comprising the amino acid sequence of SEQ ID NO: 4 or 5.

24. The method of claim 23 , wherein the antibody of the immunoconjugate comprises (i) a heavy chain comprising the same amino acid sequence as the amino acid sequence of the heavy chain encoded by the plasmid deposited with the ATCC as PTA-10772 and (ii) a light chain comprising the same amino acid sequence as the amino acid sequence of the light chain encoded by the plasmid deposited with the ATCC as PTA-10773 or PTA-10774.

25. The method of claim 22 , wherein the reference sample comprises tissue, cells, or cell pellets.

26. The method of claim 22 , wherein the reference sample is a negative reference sample.

27. The method of claim 22 , wherein the antibody or antigen binding fragment thereof for detecting F OLR1 expression is the antibody BN3.2.

28. The method of claim 22 , wherein the tumor tissue sample has greater than 75% of cells having a staining intensity score of 3 or greater.