Anti-transferrin receptor / anti-BACE1 multispecific antibodies and methods of use

1. A multispecific antibody comprising a first half antibody comprising a first antigen binding site that binds to human transferrin receptor (TfR) and primate TfR, wherein the antibody does not inhibit the binding of transferrin to TfR; and a second half antibody comprising a second antigen binding site that binds BACE1, wherein the second antigen binding site comprises: (i) HVR-H1, HVR-H2, and HVR-H3, respectively comprising the amino acid sequences of:

(a) SEQ ID NOs: 165, 179, and 202;

(b) 376, 377, and 202;

(c) 376, 377, and 378;

(d) 376, 377, and 379;

(e) 380, 179, and 384;

(f) 381, 179, and 202;

(g) 382, 179, and 202;

(h) 165, 383, and 385;

or (i) 165, 179, and 379 and (ii) HVR-L1, HVR-L2, and HVR-L3, respectively comprising the amino acid sequences of:

(a) SEQ ID NO: 215, 221, and 230;

(b) 215, 223, and 230; or

(c) 215, 375, and 230;

and wherein the first antigen binding site comprises (iii) HVR-H1, HVR-H2, and HVR-H3, respectively comprising the amino acid sequences of:

(a) SEQ ID NOs: 53, 54 and 55;

(b) SEQ ID NOs: 53, 406 and 55; or

(c) SEQ ID NOs: 53, 407 and 55;

and (iv) HVR-L1, HVR-L2, and HVR-L3, respectively comprising the amino acid sequences of:

(a) SEQ ID NOs: 50, 51 and 52 or

(b) SEQ ID NOs: 50, 51 and 408.

2. The antibody of claim 1 , wherein each of the first half antibody and the second half antibody is a monoclonal antibody.

3. The antibody of claim 1 , wherein the first antigen binding site is human or humanized.

4. The antibody of claim 1 , wherein the second antigen binding site is human.

5. The antibody of claim 1 , wherein the first antigen binding site comprises (a) a VH sequence having at least 95% sequence identity to the amino acid sequence of SEQ ID NO: 108, 403 or 404; or (b) a VL sequence having at least 95% sequence identity to the amino acid sequence of SEQ ID NO: 401 or 402; or (c) a VH sequence as in (a) and a VL sequence as in (b).

6. The antibody of claim 1 , wherein the first antigen binding site comprises a heavy chain variable region (VH) sequence of SEQ ID NO: 108, 403, or 404; and a light chain variable region (VL) sequence of SEQ ID NO: 401 or 402.

7. The antibody of claim 1 , wherein the first antigen binding site comprises:

a) a VH sequence of SEQ ID NO: 108 and a VL sequence of SEQ ID NO: 401;

b) a VH sequence of SEQ ID NO: 108 and a VL sequence of SEQ ID NO: 402;

c) a VH sequence of SEQ ID NO: 403 and a VL sequence of SEQ ID NO: 401; or

d) a VH sequence of SEQ ID NO: 404 and a VL sequence of SEQ ID NO: 401.

8. The antibody of claim 1 , wherein the second antigen binding site comprises:

a) a heavy chain variable domain sequence having at least 90% sequence identity to a sequence selected from SEQ ID NOs: 288, 352 to 358, 367 to 374, and 399; or

b) a light chain variable domain sequence having at least 90% sequence identity to a sequence selected from SEQ ID NOs: 306, 345 to 351, and 359 to 366; or

c) a heavy chain variable domain sequence as in (a) and a light chain variable domain sequence as in (b).

9. The antibody of claim 1 , wherein the second antigen binding site comprises:

a) a heavy chain variable domain sequence having a sequence selected from SEQ ID NOs: 288, 352 to 358, 367 to 374, and 399; or

b) a light chain variable domain sequence having a sequence selected from SEQ ID NOs: 306, 345 to 351, and 359 to 366; or

c) a heavy chain variable domain sequence as in (a) and a light chain variable domain sequence as in (b).

10. The antibody of claim 1 , wherein the antibody is a human IgG1 or IgG4 antibody.

11. The antibody of claim 1 , wherein the first half antibody comprises a first heavy chain and a first light chain, and the second half antibody comprises a second heavy chain and a second light chain, wherein:

a) the first heavy chain and the first light chain are selected from SEQ ID NOs: 329 and 330, SEQ ID NOs: 333 and 334, SEQ ID NOs: 337 and 338, SEQ ID NOs: 341 and 342, and SEQ ID NOs: 394 and 342; and

b) the second heavy chain and the second light chain are selected from SEQ ID NOs: 331 and 332, SEQ ID NOs: 335 and 336, SEQ ID NOs: 339 and 340, and SEQ ID NOs: 343 and 344.

12. The antibody of claim 11 , wherein:

a) the first heavy chain and the first light chain are selected from SEQ ID NOs: 333 and 334, SEQ ID NOs: 341 and 342, and SEQ ID NOs: 394 and 342; and

b) the second heavy chain and the second light chain are selected from SEQ ID NOs: 335 and 336, and SEQ ID NOs: 343 and 344.

13. The antibody of claim 1 , wherein the antibody comprises a first heavy chain constant region and a second heavy chain constant region.

14. The antibody of claim 13 , wherein the first heavy chain constant region is fused to the first antigen binding site and the second heavy chain constant region is fused to the second antigen binding site; or wherein the first heavy chain constant region is fused to the second antigen binding site and the second heavy chain constant region is fused to the first antigen binding site.

15. The antibody of claim 13 , wherein the antibody is an IgG1 antibody, wherein the antibody comprises a knob mutation, and wherein the knob mutation comprises a T366W mutation.

16. The antibody of claim 15 , wherein the antibody is an IgG1 antibody, wherein the antibody comprises a hole mutation, and wherein the hole mutation comprises at least one, at least two, or three mutations selected from T366S, L368A, and Y407V.

17. The antibody of claim 13 , wherein the antibody is an IgG4 antibody, wherein the antibody comprises a knob mutation, and wherein the knob mutation comprises a T366W mutation.

18. The antibody of claim 17 , wherein the antibody is an IgG4 antibody, wherein the antibody comprises a hole mutation, and wherein the hole mutation comprises at least one, at least two, or three mutations selected from T366S, L368A, and Y407V mutations.

19. The antibody of claim 13 , wherein the Fc region comprises a modification selected from N297G; D265A and N297A; and D265A and N297G.

20. The antibody of claim 13 , wherein the Fc region comprises L234A, L235A, and P329G modifications.

21. The antibody of claim 13 , wherein the Fc region comprises M252Y, S254T and T256E modifications.

22. The antibody of claim 13 , wherein the Fc region comprises N434A and Y436I modifications.

23. A multispecific antibody comprising a first half antibody comprising a first antigen binding site that binds to human transferrin receptor (TfR) and primate TfR, and a second half antibody comprising a second antigen binding site that binds BACE1, wherein:

a) the first half antibody comprises a first heavy chain having the sequence of SEQ ID NO: 394 and a first light chain having the sequence of SEQ ID NO: 342, and the second half antibody comprises a second heavy chain having the sequence of SEQ ID NO: 343 and a second light chain having the sequence of SEQ ID NO: 344; or

b) the first half antibody comprises a first heavy chain variable region comprising the sequence of SEQ ID NO: 396 and a first light chain variable region comprising the sequence of SEQ ID NO: 398, and the second half antibody comprises a second heavy chain variable region comprising the sequence of SEQ ID NO: 399 and a second light chain variable region comprising the sequence of SEQ ID NO: 400.

24. A pharmaceutical formulation comprising the antibody of claim 1 and a pharmaceutically acceptable carrier.

25. The pharmaceutical formulation of claim 24 comprising red blood cells, reticulocytes, or a compound selected from erythropoietin (EPO), an iron supplement, vitamin C, folic acid, and vitamin B12.