NOVEL HETERODIMERIC PROTEINS

18 .- 30 . (canceled)

31 . A heterodimeric antibody comprising:

a) a first heavy chain comprising:

i) a first variant Fc domain; and

ii) a single chain Fv region that binds a first antigen; and

b) a second heavy chain comprising:

i) a second variant Fc domain;

ii) a first variable heavy chain; and

iii) a first light chain;

wherein said first and second variant Fc domains each comprise amino acid substitution(s) selected from the group consisting of 236A, 239D, 239E, 332E, 332D, 239D/332E, 267D, 267E, 328F, 267E/328F, 236A/332E, 239D/332E/330Y, 239D, 332E/330L, 299T, 434S, 428L, 308F, 259I, 428L/434S, 2591/308F, 4361/428L, 436I/434S, 436V/434S, 436V/428L and 259I/308F/428L.

32 . A heterodimeric antibody according to claim 31 wherein the pIs of said first heavy chain and said second heavy chain are at least 0.5 logs apart.

33 . A heterodimeric antibody according to claim 32 wherein one of said heavy chains comprises a pI variant selected from the group consisting of S119E, K133E, K133Q, R133E (in case of IgG2-4), R133Q (in case of IgG2-4), T164E, K205E, K205Q, N208D, K210E, K210Q, K274E, K320E, K322E, K326E, K334E, R355E, K392E, Deletion of K447, adding peptide DEDE at the c-terminus, G137E, N203D, K274Q, R355Q, K392N and Q419E, 349A, 349C, 349E, 3491, 349K, 349S, 349T, 349W, 351E, 351K, 354C, 356K, 357K, 364C, 364D, 364E, 364F, 364G, 364H, 364R, 364T, 364Y, 366D, 366K, 366S, 366W, 366Y, 368A, 368E, 368K, 368S, 370C, 370D, 370E, 370G, 370R, 370S, 370V, 392D, 392E, 394F, 394S, 394W, 394Y, 395T, 395V, 396T, 397E, 397S, 397T, 399K, 401K, 405A, 405S, 407T, 407V, 409D, 409E, 411D, 411E, 411K, 439D, 349C/364E, 349K/351K, 349K/351K/394F, 349K/354C, 349K/394F, 349K/394F/401K, 349K/394Y, 349K/401K, 349K/405A, 349T/351E/411E, 349T/394F, 349T/394F/401K, 349T/394F/411E, 349T/405A, 349T/411E, 351E/364D, 351E/364D/405A, 351E/364E, 351E/366D, 351K/364H/401K, 351K/366K, 364D/370G, 364D/394F, 364E/405A, 364E/405S, 364E/411E, 364E/411E/405A, 364H/394F, 364H/401K, 364H/401K/405A, 364H/405A, 364H/405A/411E, 364Y/370R, 370E/411E, 370R/411K, 395T/397S/405A and 397S/405A.

34 . A heterodimeric antibody according to claim 32 wherein one of said first and second Fc variant Fc domains comprises amino acid substitutions ISO(−):

I199T/N203D/K274Q/R355Q/N384S/K392N/V397M/Q419E/DEL44 and the other are ISO(+RR): Q196K/1199T/P217R/P228R/N276K.

35 . A heterodimeric antibody according to claim 31 further comprising a conjugated drug.

36 . A composition comprising a heterodimeric antibody according to claim 31 and a carrier.

37 . A nucleic acid encoding said first heavy chain of claim 31 .

38 . A nucleic acid encoding said second heavy chain of claim 31 .

39 . A nucleic acid encoding said light chain of claim 31 .

40 . A host cell comprising a first nucleic acid encoding said first heavy chain of claim 31 , a second nucleic acid encoding said second heavy chain of claim 31 , and a nucleic acid encoding said light chain of claim 31 .

41 . A method of producing a heterodimeric antibody according to claim 31 comprising:

a) culturing a host cell according to claim 40 under conditions wherein said heterodimeric antibody is produced; and

b) recovering said heterodimeric antibody.

42 . A method of purifying a heterodimeric antibody comprising:

a) providing an antibody according to claim 31 ;

b) loading said composition onto an ion exchange column; and

c) collecting the heterodimeric fraction.

43 . A method of treating an individual in need thereof comprising administering the composition of claim 36 .