Anti-cd71 antibodies, activatable anti-cd71 antibodies, and methods of use thereof

An activatable antibody that, in an activated state, specifically binds to mammalian CD71 comprising:

• an antibody or an antigen binding fragment thereof (AB) that specifically binds to mammalian CD71, wherein the AB specifically binds human CD71 and cynomolgus monkey CD71;
• a masking moiety (MM) coupled to the AB that inhibits the binding of the AB to CD71 when the activatable antibody is in an uncleaved state;
• and
• a cleavable moiety (CM) coupled to the AB, wherein the CM is a polypeptide that functions as a substrate for a protease.

An activatable antibody comprising an antibody or an antigen binding fragment thereof (AB) that specifically binds to mammalian CD71, a MM, and a CM, wherein the activatable antibody has one or more of the following characteristics selected from the group consisting of:

• (i) the activatable antibody comprises a heavy chain sequence of SEQ ID NOS:
• 325 or 699;
• and a light chain comprising an amino acid sequence selected from the group consisting of SEQ ID NOS:
• 327, 329, 331, 333, 335, 337, 650, 652, 654, 656, 658, 660, 670-673, 701-712, and 721-788;
• (ii) the MM comprises an amino acid sequence selected from the group consisting of SEQ ID NOs:
• 16-295 and 297-314, and the CM comprises an amino acid sequence selected from the group consisting of SEQ ID NOs:
• 356-423, 680-698, 713, 714, and 789-808;
• (iii) the AB comprises the VH CDR1 sequence GYTFTSYWMH (SEQ ID NO:
• 9), the VH CDR2 sequence AIYPGNSETG (SEQ ID NO:
• 10), the VH CDR3 sequence ENWDPGFAF (SEQ ID NO:
• 11), the VL CDR1 sequence SASSSVYYMY (SEQ ID NO:
• 12) or CRASSSVYYMY (SEQ ID NO:
• 13), the VL CDR2 sequence STSNLAS (SEQ ID NO:
• 14), and the VL CDR3 sequence QQRRNYPYT (SEQ ID NO:
• 15);
• (iv) the activatable antibody comprises a heavy chain variable region comprising an amino acid sequence selected from the group consisting of SEQ ID NOs:
• 3-5, and a light chain variable region comprising an amino acid sequence selected from the group consisting of SEQ ID NOs:
• 6-8, 809-836, and 841-908;
• and
• (v) the AB comprises the VH CDR1 sequence GYTFTSYWMH (SEQ ID NO:
• 9), the VH CDR2 sequence AIYPGNSETG (SEQ ID NO:
• 10), the VH CDR3 sequence ENWDPGFAF (SEQ ID NO:
• 11), the VL CDR1 sequence SASSSVYYMY (SEQ ID NO:
• 12) or CRASSSVYYMY (SEQ ID NO:
• 13), the VL CDR2 sequence STSNLAS (SEQ ID NO:
• 14), and the VL CDR3 sequence QQRRNYPYT (SEQ ID NO:
• 15), the MM comprises an amino acid sequence selected from the group consisting of SEQ ID NOs:
• 16-295 and 297-314, and the CM comprises an amino acid sequence selected from the group consisting of SEQ ID NOs:
• 356-423, 680-698, 713, 714, and 789-808.

A conjugated activatable antibody that, in an activated state, binds CD71 comprising:

• (a) an activatable antibody comprising:
• (i) an antibody or an antigen binding fragment thereof (AB) that specifically binds to mammalian CD71, wherein the AB specifically binds human CD71 and cynomolgus monkey CD71;
• (ii) a masking moiety (MM) coupled to the AB that inhibits the binding of the AB to CD71 when the activatable antibody is in an uncleaved state;
• and
• (iii) a cleavable moiety (CM) coupled to the AB, wherein the CM is a polypeptide that functions as a substrate for a protease;
• and
• (b) an agent conjugated to the AB.

A conjugated antibody comprising:

• (a) an antibody or an antigen binding fragment thereof (AB) that specifically binds to mammalian CD71, wherein the AB comprises:
• (i) the VH CDR1 sequence GYTFTSYWMH (SEQ ID NO:
• 9);
• the VH CDR2 sequence AIYPGNSETG (SEQ ID NO:
• 10);
• the VH CDR3 sequence ENWDPGFAF (SEQ ID NO:
• 11);
• the VL CDR1 sequence SASSSVYYMY (SEQ ID NO:
• 12) or CRASSSVYYMY (SEQ ID NO:
• 13);
• the VL CDR2 sequence STSNLAS (SEQ ID NO:
• 14);
• and the VL CDR3 sequence QQRRNYPYT (SEQ ID NO:
• 15), or
• (ii) a heavy chain variable region comprising an amino acid sequence selected from the group consisting of SEQ ID NOs:
• 3-5, and a light chain variable region comprising an amino acid sequence selected from the group consisting of SEQ ID NOs:
• 6-8;
• and
• (b) an agent conjugated to the AB, wherein the agent is selected from the group consisting of auristatin E, monomethyl auristatin F (MMAF), monomethyl auristatin E (MMAE), monomethyl auristatin D (MMAD), maytansinoid DM4, maytansinoid DM1, a calicheamicin, a pyrrolobenzodiazepine, a pyrrolobenzodiazepine dimer, and a duocarmycin.

A conjugated activatable antibody that, in an activated state, specifically binds to mammalian CD71, comprising:

• (a) an activatable antibody comprising:
• (i) an antibody or an antigen binding fragment thereof (AB) that specifically binds to mammalian CD71, wherein the AB specifically binds human CD71 and cynomolgus monkey CD71;
• (ii) a masking moiety (MM) coupled to the AB that inhibits the binding of the AB to CD71 when the activatable antibody is in an uncleaved state;
• (iii) a cleavable moiety (CM) coupled to the AB, wherein the CM is a polypeptide that functions as a substrate for a protease;
• and
• (b) an agent conjugated to the AB,
• wherein the activatable antibody comprises:
• (i) the VH CDR1 sequence GYTFTSYWMH (SEQ ID NO:
• 9);
• the VH CDR2 sequence AIYPGNSETG (SEQ ID NO:
• 10);
• the VH CDR3 sequence ENWDPGFAF (SEQ ID NO:
• 11);
• the VL CDR1 sequence SASSSVYYMY (SEQ ID NO:
• 12) or CRASSSVYYMY (SEQ ID NO:
• 13);
• the VL CDR2 sequence STSNLAS (SEQ ID NO:
• 14);
• and the VL CDR3 sequence QQRRNYPYT (SEQ ID NO:
• 15), or
• (ii) a heavy chain variable region comprising an amino acid sequence selected from the group consisting of SEQ ID NOs:
• 3-5, and a light chain variable region comprising an amino acid sequence selected from the group consisting of SEQ ID NOs:
• 6-8, 809-836, and 841-908, or
• (iii) a heavy chain comprising the amino acid sequence of SEQ ID NOS:
• 325 or 699, and a light chain comprising an amino acid sequence selected from the group consisting of SEQ ID NOS:
• 327, 329, 331, 333, 335, 337, 650, 652, 654, 656, 658, 660, 670-673, 701-712, and 721-788;
• and
• wherein the agent is selected from the group consisting of auristatin E, monomethyl auristatin F (MMAF), monomethyl auristatin E (MMAE), monomethyl auristatin D (MMAD), maytansinoid DM4, maytansinoid DM1, a calicheamicin, a pyrrolobenzodiazepine, a pyrrolobenzodiazepine dimer, and a duocarmycin.

A conjugated activatable antibody or conjugated antibody comprising:

• an antibody or antigen binding fragment thereof (AB) that, in an activated state, binds CD71;
• and
• a toxin conjugated to the AB via a linker,
• wherein the conjugated activatable antibody or the conjugated antibody comprises amino acid sequences, a linker, and a toxin selected from a single row in Table F, wherein for the given combination:
• (a) the AB comprises a heavy chain comprising the amino acid sequence of the heavy chain sequence or heavy chain variable domain sequence corresponding to the given combination in the single row listed in Table F,
• (b) the AB comprises a light chain comprising the amino acid sequence of the light chain sequence or light chain variable domain sequence corresponding to the given combination in the single row listed in Table F, and
• (c) the linker and the toxin comprise the linker and the toxin corresponding to the given combination in the single row listed in Table F.