Monday, July 5, 2021

Vaccine ‘encouraging’ in certain ovarian cancer patients, researcher tells ASCO meeting

A vaccine made from a patient’s own cancer cells kept ovarian cancer from recurring in a group of patients with specific types of tumors that typically are less responsive to therapy, according to a study presented by a USA Health researcher at the annual meeting of the American Society of Clinical Oncology. Further, by analyzing DNA data, researchers were able to predict which ovarian cancer patients were likely to benefit the most from the vaccine.

The presenter, Rodney P. Rocconi, M.D., a gynecologic oncologist at USA Health and professor of gynecologic oncology at the USA College of Medicine, said the results of the VITAL study, a phase 2b clinical trial, set the stage for further clinical research on an international scale.

“These results are extremely encouraging in offering increased survivals in patients that currently have an unmet need with homologous recombination proficient (HRP) ovarian cancer,” Rocconi said. “Historically, patients with HRP cancers have significantly lower responses to chemotherapy with survivals that are approximately 20 months lower than other patients with ovarian cancer.”

The VITAL trial enrolled patients diagnosed with advanced stage III or IV ovarian cancer who had a complete response to surgery and standard combination chemotherapy. After this response, patients were randomized to either the Vigil vaccine or placebo.

Compared to placebo, patients receiving the Vigil vaccine demonstrated significantly better overall survival at two years from 55 percent to 92 percent. This survival advantage was extended to a three-year overall survival of 40 percent to 70 percent.

The clinical benefit was shown in patients with homologous recombination proficient (HRP) ovarian cancer, which makes up nearly 50 percent of all ovarian cancer diagnoses. These HRP cancers are capable of effectively repairing DNA damage caused by chemotherapy and thus are associated with resistance to traditional therapy.

The researchers also analyzed protein-DNA pathway interactions and found a unique molecular subset that may enhance a patient’s sensitivity to the Vigil vaccine.

“It’s exciting to demonstrate an effective therapy that possibly could change the standard of care for essentially half of all ovarian cancer patients,” Rocconi said. “Although further studies are needed, our research shows that we are able to predict which patients are most likely to benefit from this novel vaccine.”