Ovarian cancer is the fifth leading cause of cancer death among women and the most lethal gynecological cancer in the US. More than 90% of ovarian cancer occurs in the epithelium, the thin layer of tissue that covers the ovaries. Unfortunately, diagnosis typically occurs at an advanced stage of disease after the cancer has spread beyond the ovary. The first-line treatment for advanced ovarian cancer includes surgery and a platinum-paclitaxel chemotherapy regimen. Staging of ovarian cancer is determined by how far the cancer has spread and correlates with prognosis.
Despite recent treatment advances dramatically increasing survival rates for other types of cancer in women, including breast and cervical, the incidence and mortality of ovarian cancer have not changed in 50 years. Even with modest improvements in patient outcomes as a result of surgery or chemotherapy, most ovarian cancer patients relapse and die of their disease. Yearly estimates for treatment of ovarian cancer in the US are $5–6 billion. There is a clearly a need for more effective systemic therapies.
A large proportion of patients do not successfully respond to platinum-based therapies, and 70–90% of women with ovarian cancer will have a recurrence at some point after their diagnosis, depending on how advanced the disease was. Cynvec’s preclinical and clinical development have great potential for success for several reasons. Sindbis and other viral vectors may help address many limitations of checkpoint inhibitors and CAR-T technology. They can induce effective immune cell infiltration into tumors, which has proven problematic for CAR-T and many forms of immune therapies. It can also increase expression of checkpoint proteins and other T-cell receptors that are downregulated in many cancers but are required for the immune therapies to work.