title: Curing mice with large tumors by locally delivering combinations of immunomodulatory antibodies.
abstract: OBJECTIVE
  Immunomodulatory mAbs can treat cancer, but cures are rare except for small tumors. Our objective was to explore whether the therapeutic window increases by combining mAbs with different modes of action and injecting them into tumors.
  
  
  METHODS
  Combinations of mAbs to CD137/PD-1/CTLA-4 or CD137/PD-1/CTLA-4/CD19 were administrated intratumorally to mice with syngeneic tumors (B16 and SW1 melanoma, TC1 lung carcinoma), including tumors with a mean surface of approximately 80 mm(2). Survival and tumor growth were assessed. Immunologic responses were evaluated using flow cytometry and qRT-PCR.
  
  
  RESULTS
  More than 50% of tumor-bearing mice had complete regression and long-term survival after tumor injection with mAbs recognizing CD137/PD-1/CTLA-4/CD19 with similar responses in three models. Intratumoral injection was more efficacious than intraperitoneal injection in causing rejection also of untreated tumors in the same mice. The three-mAb combination could also induce regression, but was less efficacious. There were few side effects, and therapy-resistant tumors were not observed. Transplanted tumor cells rapidly caused a Th2 response with increased CD19 cells. Successful therapy shifted this response to the Th1 phenotype with decreased CD19 cells and increased numbers of long-term memory CD8 effector cells and T cells making IFNγ and TNFα.
  
  
  CONCLUSIONS
  Intratumoral injection of mAbs recognizing CD137/PD-1/CTLA-4/CD19 can eradicate established tumors and reverse a Th2 response with tumor-associated CD19 cells to Th1 immunity, whereas a combination lacking anti-CD19 is less effective. There are several human cancers for which a similar approach may provide clinical benefit.
authors.affiliation: University of Washington Harborview Medical Center, Department of Pathology, Seattle, Washington.
authors.forename: Min
authors.initials: M
authors.lastname: Dai
authors.affiliation: University of Washington Harborview Medical Center, Department of Pathology, Seattle, Washington.
authors.forename: Yuen Yee
authors.initials: YY
authors.lastname: Yip
authors.affiliation: University of Washington Harborview Medical Center, Department of Pathology, Seattle, Washington.
authors.forename: Ingegerd
authors.initials: I
authors.lastname: Hellstrom
authors.affiliation: University of Washington Harborview Medical Center, Department of Pathology, Seattle, Washington. hellsk@u.washington.edu.
authors.forename: Karl Erik
authors.initials: KE
authors.lastname: Hellstrom
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000008:administration & dosage*; D060890:B7-H1 Antigen / Q000037:antagonists & inhibitors; D015415:Biomarkers / Q000378:metabolism; D060908:CTLA-4 Antigen / Q000037:antagonists & inhibitors; D045744:Cell Line, Tumor; D004195:Disease Models, Animal; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D007155:Immunologic Factors / Q000008:administration & dosage*; D015552:Injections, Intralesional; D007274:Injections, Intraperitoneal; D051379:Mice; D009369:Neoplasms / Q000188:drug therapy / Q000276:immunology* / Q000401:mortality / Q000473:pathology*; D018418:Th2 Cells / Q000276:immunology / Q000378:metabolism; D047368:Tumor Burden / Q000187:drug effects / Q000276:immunology; D059016:Tumor Microenvironment / Q000187:drug effects / Q000276:immunology; D053261:Tumor Necrosis Factor Receptor Superfamily, Member 9 / Q000037:antagonists & inhibitors
chemical_list: D000911:Antibodies, Monoclonal; D060890:B7-H1 Antigen; D015415:Biomarkers; D060908:CTLA-4 Antigen; D007155:Immunologic Factors; D053261:Tumor Necrosis Factor Receptor Superfamily, Member 9