Phase I Study of Local Radiation and CP-675,206 Administration in Patients With Inoperable Locally Recurrent or Metastatic Breast Cancer
Breast cancer is the most common cancer in Canadian women. In 2007 an estimated 22,300 women
will be diagnosed and 5300 will die of the disease. Despite advances in therapy, metastatic
disease remains an incurable illness, with a median survival of only 2 years. Standard
systemic treatment options for metastatic disease include chemotherapy or hormonal therapy.
Radiation is frequently used in the metastatic setting for palliation of symptoms, with the
most frequent site of radiation being bone. Response rates to first line chemotherapy are in
the range of 30%, however these responses are not durable. Currently there are no curative
options for metastatic disease, underscoring the need for novel therapeutic approaches.
CTLA4 is a receptor expressed on the surface of activated T cells and regulatory T cells.
CTLA-blockade has been tested in clinical trials using humanized monoclonal antibodies, and
some biological responses have been reported. The anti-tumor immune response may be further
augmented by the combination of CTLA4-blockade with radiation, with the potential to mediate
regression of metastases outside of the field of radiation. The primary goal of this study
therefore is to establish the safety of CTLA4-blockade using the antibody CP-675, 206 in
combination with radiation. This trial is being conducted as a prelude to a planned phase II
trial of CP-675,206 in combination with radiation in metastatic breast cancer.
Endpoint Classification: Safety Study, Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Treatment
Assessing safety through toxicities observed using CTCAE version 3.0
At each study visit for the duration of the 12-week cycle
Srikala Sridhar, MD FRCPC
University Health Network - Princess Margaret Hospital
Canada: Ethics Review Committee