Patients with persistent or recurrent metastatic carcinoma of the cervix (PRmCC) who took the vaccine survived 52 percent longer than patients who received standard of care treatment, the trial investigators reported. And the therapy was generally well-tolerated.
Charles A. Leath III, MD, associate professor of obstetrics and gynecology at the University of Alabama, presented the Phase 2 trial results at the Society of Gynecologic Oncology’s Annual Meeting on Women’s Cancer March 12-15 in National Harbor, Maryland. His presentation was titled “A prospective phase 2 trial of the listeria-based HPV immunotherapy axalimogene filolisbac in second and third-line metastatic cervical cancer: A NRG oncology group trial.”
Axalimogene filolisbac is an immunotherapy vaccine that targets cancers associated with the human papillomavirus, or HPV. It uses bioengineered live Listeria monocytogenes bacteria to generate T-cells that go after HPV-positive cancer cells. It also neutralizes immunosuppressive cells — such as regulatory T-cells and myeloid-derived suppressor cells — that prevent the immune system from attacking the tumor microenvironment.
The Gynecologic Oncology Group (GOG) conducted the GOG-0265 trial (NCT01266460). The open-label, single-arm, two-part study was designed to evaluate the effectiveness, safety, and tolerability of axalimogene filolisbac in patients whose cancer had worsened during or after chemotherapy.
The study’s primary endpoints, or yardsticks, were 12-month survival rate, the number of patients who developed toxicities that limited their vaccine dose, and the severity of adverse events. Secondary endpoints included progression-free survival, objective survival, and objective tumor response.
Thirty-eight percent of patients treated with axalimogene filolisbac were alive 12 months after receiving the vaccine, the trial showed.
The researchers had calculated an expected 12-month patient survival rate for the GOC-0265 trial by using information from a database that covered nearly 500 PRmCC patients. The 500 had taken part in 17 previous Phase 2 trials the GOC had conducted.
The researchers included prognosis factors such as age, race, and disease status in their survival-rate calculation.
They came up with an expected 12-month survival rate of 24.5% of the patients. The actual rate of 38% of patients represented a 52% improvement over the expected rate.
“The 12-month survival rate of axalimogene filolisbac reached unprecedented levels in this study, which is both impressive and important given the lack of innovation in metastatic cervical cancer,” Warner K. Huh, MD, division director of gynecologic oncology at the University of Alabama at Birmingham, said in a news release. He was the lead investigator of the study.
The main adverse events of the treatment were low-grade anemia, fatigue, nausea, chills, and fever. Only two patients experienced more serious adverse events.
Based on the findings, Advaxis is planning a global Phase 3 trial of the vaccine by the end of the year for patients with metastatic cervical cancer.