The present invention relates to certain anti-M(H)DM2/4 antibodies orantigen- binding fragments thereof, pharmaceutical compositionscomprising anti-M(H)DM2/4 antibodies or antigen-binding fragmentsthereof, antibody-drug conjugates comprising anti-M(H)DM2/4 antibodies orantigen-binding fragments thereof bound to a cytotoxic drug, and the use ofsuchantibodies, fragments, compositions and conjugates for treating cancer and/or for preventing metastases. In particular, described herein are certainantibodies or antigen-binding fragments thereof that specifically bind toextracellularly accessible epitopes of M(H)DM2/4 and inhibit tumor growth invivo,pharmaceutical compositions comprising such antibodies or fragments,antibody-drug conjugates comprising such antibodies or fragments, and the useof such antibodies, fragments, compositions and conjugates for treatingcancer or for preventing metastasis.
