COMBINATION THERAPIES FOR TREATING HER2-POSITIVE CANCERS THAT ARE RESISTANT TO HER2-TARGETED THERAPIES
Methods for treating cancer patients (e.g., cancer patients resistant or intolerant to pertuzumab and ado-trastuzumab emtansine) having HER2-positive tumors are disclosed. The methods comprise administering to a patient a therapeutically effective amount of a combination of a doxorubicin-loaded immunoliposome with a targeting moiety that is an anti-HER2 antibody that is not an inhibitor of HER2 signaling and an anti-cancer therapeutic comprising a doxorubicin-free anti-cancer therapeutic comprising a different anti-HER2 antibody.
1 . A method of follow-on treatment of a HER2-positive tumor in a human patient comprising administering to the patient a therapeutically effective amount of an immunoliposome comprising encapsulated doxorubicin and a HER2-binding antibody, in combination with an anti-HER2 therapeutic that comprises trastuzumab or another anti-HER2 antibody, wherein, prior to the follow-on treatment, the patient had received treatment with one or more of 1) trastuzumab, 2) pertuzumab, and 3) ado-trastuzumab emtansine, and had experienced tumor progression following such prior treatment initiation with, or was intolerant to treatment with pertuzumab and had experienced tumor progression following such prior treatment initiation with, or was intolerant to such prior treatment with ado-trastuzumab emtansine.
2 . The method of claim 1 , wherein (i) the immunoliposome is an immunoliposome comprising encapsulated doxorubicin and an immunoliposome-associated anti-HER2 antibody that is not an inhibitor of HER2 signaling and is oriented on the immunoliposome so as to be able to bind to an antigen that is external to the immunoliposome and (ii) the anti-HER2 therapeutic is a doxorubicin-free therapeutic comprising an anti-HER2 antibody that a) is an inhibitor of HER2 signaling, or that b) does not bind to the same epitope of HER2 that is bound by the immunoliposome-associated antibody, or that c) does not compete with the immunoliposome-associated antibody for immunospecific binding to HER2, or that a) and b), or that a) and c), or that b) and c), or that a) and b) and c).
3 . The method of claim 2 , wherein the immunoliposome is administered intravenously.
4 . The method of claim 3 , wherein the patient has not previously been treated with a systemically administered anthracycline.
5 . The method of claim 4 , wherein the immunoliposome-associated anti-HER2 antibody is a single-chain Fv (scFv).
6 . The method of claim 5 , wherein scFv is an F5 scFv comprising the amino acid sequence encoded byATCC plasmid deposit designation PTA7843.
7 . The method of claim 6 , wherein the immunoliposome is MM-302 and the doxorubicin-free anti-cancer therapeutic is trastuzumab.
8 . The method of claim 7 , wherein the tumor is a breast cancer tumor.
9 . The method of claim 8 , wherein the breast cancer is histologically or cytologically characterized as invasive cancer of the breast.
10 . The method of claim 9 , wherein the breast cancer is either or both of locally advanced and metastatic.
11 . The method of claim 10 , wherein the breast cancer is not amenable to resection with curative intent.
12 . The method of claim 11 , wherein, prior to initial administration of the immunoliposome, an antihistamine is administered orally or intravenously as prophylactic premedication.
13 . The method of claim 12 , wherein the method comprises at least one 3-week treatment cycle in which the signaling-inhibitory anti-HER2 antibody is administered at a dose of 6 mg/kg per administration and the immunoliposome is administered at a dose of 30 mg/m 2 per administration;
and wherein,
when the at least one cycle is a single cycle, the anti-HER2 antibody and the immunoliposome are each administered once;
and wherein, when the at least one cycle is a plurality of cycles, the signaling-inhibitory anti-HER2 antibody is administered every three weeks and the immunoliposome is administered every three weeks or every four weeks.