City of Hope has opened a first-in-human clinical trial evaluating the use of a cancer-killing oncolytic virus to treat patients with metastatic triple-negative breast cancer.
The City of Hope-developed therapy, CF33-hNIS-antiPDL1, is genetically engineered from a naturally occurring virus (chimeric oncolytic orthopoxvirus). The patents covering CF33-hNIS-antiPDL1 have been licensed to Imugene Limited (ASX:IMU), a company developing immunotherapies that seek to activate the immune system of cancer patients to treat and eradicate tumors. CF33-hNIS-antiPDL1 is designed to infect, replicate in and kill cancer cells while sparing healthy cells.
Yuan Yuan, M.D., Ph.D., associate professor in City of Hope’s Department of Medical Oncology & Therapeutics Research and principal investigator of the Phase 1 clinical trial. “Current approved therapies do not offer a cure for this aggressive type of breast cancer, which often becomes resistant to chemotherapy. Clinical trials like this one seek durable responses and better quality of life for patients.”
The researchers seek to determine the appropriate dose of CF33-hNIS-antiPDL1 and ascertain if it is a safe and potentially effective treatment for patients with triple-negative breast cancer that is advanced or has spread to other places in the body. It will be tested in patients whose cancer has progressed through standard-of-care chemotherapy.
Triple-negative breast cancer affects about 15-20% of all breast cancer patients. It is a challenging disease to treat — most Food and Drug Administration-approved therapies prolong survival for a median of two years, Yuan said. Despite the recent FDA approval of targeted therapy for BRCA gene mutation (that is, immune checkpoint inhibitor pembrolizumab and Trop-2 antibody drug conjugate), the majority of patients continue to progress after the first two lines of therapy. There is an unmet need for patients whose triple-negative breast cancer has progressed despite previous treatment regimens.
The cancer-killing effects of CF33 have been observed for the following cancer cell types in the preclinical setting: pancreatic, stomach, lung, ovarian and colon. Published preclinical data show that the CF33 oncolytic virus can increase the presence of immune checkpoint inhibitors, which can help enhance the immune system’s ability to do its job.
Preclinical research has shown that this oncolytic virus can direct the killing of cancers and stimulate the immune system to enable further killing of cancers,” said Yuman Fong, M.D., the Sangiacomo Family Chair in Surgical Oncology at City of Hope who developed CF33. “This trial is an important step forward.”
The three-year trial seeks to enroll patients who have been diagnosed with recurrent metastatic triple-negative breast cancer who experienced disease progression after standard-of-care therapies. Study participants may receive a total of three cycles of six doses of the treatment through direct injection into the tumor.
Scientists will be able to say that the oncolytic virus activated the immune system against breast cancer if they note increased expression of checkpoint targets PD-1, PD-L1 or CTLA-4 and increased CD8+ immune cells. When there are more of these checkpoint targets, current approved and experimental therapies are better able to grab onto and unlock cancer cells to destroy them from the inside.
More information about the clinical trial can be found at CityofHope.org/research/find-a-clinical-trial or clinicaltrials.gov.