OncoVAX is a cancer vaccine that Vaccinogen is developing to prevent the return of stage 2 colon cancer and other solid tumors after surgery.
OncoVAX uses cancer cells from a patient’s body to create an injectable vaccine.
How OncoVAX works
The first step in creating OncoVAX is removing tumor cells from a patient, sterilizing them, then using radiation to prevent them from dividing.
Doctors inject the cells back into the patient to trigger an immune response against cancer cells left after surgery. This kills the residual cells, preventing the recurrence of cancer.
Vaccinogen uses Bacillus Calmette-Guerin (BCG), a live but weakened bacteria, to help generate a potent immune response. BCG is an adjuvant, or helper, therapy that prompts the immune system to recognize previously hidden cancer cells as foreign.
Since the vaccine uses the patient’s own tumor cells, there is a high probability that the immune system will target the right tumor antigens. An antigen is a molecule capable of triggering an immune response — that is, production of an antibody — against an invader.
An OncoVAX vaccination consists of four injections over six months. The first two doses include cancer cells and BCG, while the last two are cancer cells alone. The first dose is given four to five weeks after surgery, the second dose a week later, and the third dose a week after the second. The fourth dose is administered six months after surgery as a booster.
OncoVAX in clinical trials
The safety and effectiveness of OncoVAX have been evaluated in five clinical trials, including the 8701 study published in The Lancet, which established the vaccine’s optimum dose and regimen.
A randomized, controlled, pilot clinical trial assessed OncoVAX in 80 people with cancer of the colon or rectum. The study showed significant improvement in colon cancer patients’ survival and the length of time it took for their disease to return. No benefits were seen in patients with cancer of the rectum.
Another randomized Phase 3 trial called the 5283 study covered 412 patients with stage 2 and 3 colon cancer. It compared the effect of surgery plus OncoVAX with surgery alone.
Patients received up to three weekly injections of the vaccine beginning four weeks after surgery, with BCG part of the first two injections. There was a trend toward better overall survival and longer time for the cancer to return among those who received all three doses, researchers said.
A randomized Phase 3 trial known as the 8701 study compared the effectiveness of surgery plus OncoVAX and surgery alone in 254 patients with stage 2 and Stage 3 colon cancer. Researchers aded a fourth vaccination at six months to the three-dose regimen.
OncoVAX reduced by 44 percent the risk of patients’ cancer recurring. The benefit for stage 2 patients was even better. It reduced their risk of recurrence by 61 percent, significantly increased the time it took for their cancer to return, and tended to improve their overall survival.
Vaccinogen followed the 8701 study with a bioequivalence study known as ASI 2002-01 in 15 patients. It looked at whether manufacturing OnoVAX under sterile conditions would affect patient outcomes. It showed that the manufacturing process did not affect OncoVAX’s ability to trigger an immune response.
Researchers are recruiting patients for a pivotal, randomized, multicenter Phase 3b clinical trial (NCT02448173). The ACTIVE trial will look at whether OncoVAX after surgery does a better job than surgery alone in preventing stage 2 colon cancer from returning. The goal is to recruit 550 patients.
Participants will receive the four-vaccination regimen beginning 35 days after surgery. The primary measure of the vaccine’s effectiveness will be whether it increases the length of time it takes for a patient’s cancer to return after surgery. Vaccinogen expects the trial to be completed by 2022.
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