A vaccine derived from a patient’s tumor cells, which enhances T-cell targeting of cancer cells, has shown promise against ovarian cancer.
This outcome of a phase 1 clinical trial was reported at the Society of Gynecologic Oncology’s 2018 Annual Meeting on Women’s Cancer, from March 24 – 27.
Rodney Rocconi, MD, of the University of South Alabama-Mitchell Cancer Institute, Mobile, explained that the majority of women with stage 3/4 ovarian cancer who achieve clinical complete response with frontline standard of care relapse within 2 years.
Vigil® is a genetically engineered vaccine made from tumor cells acquired from each patient being treated. The immunotherapy is a granulocyte-macrophage colony-stimulating factor/bi-shRNA furin DNA-engineered autologous tumor cell product.
Vigil employs the entire complement of antigens present in a patient’s cancer cells by using surgically removed tumor tissue to stimulate T-cell activation against a heterogeneous mix of cancer neoantigens specific to that patient.
With gene modification, an immunosuppressive pathway of cancer cells is downregulated while immune stimulation function of those same cells is upregulated.
When those cells are reintroduced back into the patient, these two modifications are designed to help activate the immune system to detect and kill any cancer cells that may remain locally and in circulation. Altogether, the goal is to stimulate the existing components of the immune system with the intent to improve their antitumor responses.
Tumor types studied in phase 1 trials have included but have not been limited to ovarian cancer, breast cancer, melanoma, Ewing’s sarcoma, non-small cell lung cancer, colon cancer, and hepatocellular cancer. Phase 2 studies have begun advanced ovarian cancer and Ewing’s sarcoma.
A randomized phase 2 trial combining Vigil with atezolizumab, a checkpoint inhibitor, is underway in women with ovarian, cervical and uterine cancers.
Before the 29 patients with recurrent ovarian cancer were considered for the trial, an enzyme-linked ImmunoSpot (ELISPOT) test was used to determine whether their T-cells would be activated. Those whose T-cells were activated experienced a significant increase in survival. Overall, 20 of 29 patients reached the 3-year mark of survival. Median survival has not yet been reached. Fatigue was the only reported side effect.
According to Dr. Rocconi, as more is known about cancer causes, researchers should try to be as specific as possible about the individual cancer cells that should be targeted for therapy.
He concluded that personalized treatment with Vigil immunotherapy showed excellent tolerability with limited side effects in patients with ovarian cancer. The therapy is unique because it targets the patient’s specific cancer cells. Dr. Rocconi noted that no therapy is more targeted than this.
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