Methods of Treating Conditions with Antibodies that Bind Colony Stimulating Factor 1 Receptor (CSF1R)

A method of reducing the number of CD16+ monocytes in a subject with a CD16+ disorder, comprising (a) determining the number of CD16+ monocytes in a peripheral blood sample obtained from the subject, and (b) administering to the subject an antibody that binds human colony stimulating factor 1 receptor (CSF1R) such that the number of CD16+ monocytes is reduced by at least 30%;

• wherein the antibody (i) blocks binding of human colony stimulating factor 1 (CSF1) to human CSF1R and blocks binding of human IL-34 to human CSF1R, and (ii) comprises a heavy chain comprising a heavy chain (HC) CDR1 having the sequence of SEQ ID NO:
• 15, an HC CDR2 having the sequence of SEQ ID NO:
• 16, and an HC CDR3 having the sequence of SEQ ID NO:
• 17, and a light chain comprising a light chain (LC) CDR1 having the sequence of SEQ ID NO:
• 18, a LC CDR2 having the sequence of SEQ ID NO:
• 19, and a LC CDR3 having the sequence of SEQ ID NO:
• 20.

A method of reducing the number of CD16+ monocytes in a subject with a CD16+ disorder, comprising (a) administering to the subject an antibody that binds human colony stimulating factor 1 receptor (CSF1R), (b) determining the number of CD16+ monocytes in a peripheral blood sample obtained from the subject following administration of the antibody, (c) determining whether administration of the antibody reduces the number of CD16+ monocytes in the sample by at least 30% by comparing the number of CD16+ monocytes in the sample of (b) with the number of CD16+ monocytes determined in a peripheral blood sample obtained from the subject prior to administration, and optionally (d) adjusting the dose or frequency of the administration of the antibody such that the number of CD16+ monocytes remains reduced;

• wherein the antibody (i) blocks binding of human colony stimulating factor 1 (CSF1) to human CSF1R and blocks binding of human IL-34 to human CSF1R and (ii) comprises a heavy chain comprising a heavy chain (HC) CDR1 having the sequence of SEQ ID NO:
• 15, an HC CDR2 having the sequence of SEQ ID NO:
• 16, and an HC CDR3 having the sequence of SEQ ID NO:
• 17, and a light chain comprising a light chain (LC) CDR1 having the sequence of SEQ ID NO:
• 18, a LC CDR2 having the sequence of SEQ ID NO:
• 19, and a LC CDR3 having the sequence of SEQ ID NO:
• 20.

A method of treating neoplasia in a subject, comprising (a) determining the number of CD16+ monocytes in a peripheral blood sample obtained from the subject, and (b) administering to the subject an antibody that binds human colony stimulating factor 1 receptor (CSF1R) such that the number of CD16+ monocytes is reduced by at least 30%;

• wherein the antibody (i) blocks binding of human colony stimulating factor 1 (CSF1) to human CSF1R and blocks binding of human IL-34 to human CSF1R, and (ii) comprises a heavy chain comprising a heavy chain (HC) CDR1 having the sequence of SEQ ID NO:
• 15, an HC CDR2 having the sequence of SEQ ID NO:
• 16, and an HC CDR3 having the sequence of SEQ ID NO:
• 17, and a light chain comprising a light chain (LC) CDR1 having the sequence of SEQ ID NO:
• 18, a LC CDR2 having the sequence of SEQ ID NO:
• 19, and a LC CDR3 having the sequence of SEQ ID NO:
• 20.