Listeria cancer vaccine found safe in humans

SAN DIEGO — The Listeria cancer vaccine, Lovaxin C, was reported to be safe in 15 women with progressive, recurrent or advanced cervical cancer, according to the results of a study presented this week at the 2008 Annual Meeting of the American Association for Cancer Research.

“We have modified a pathogen, a live organism with which we have an immune relationship, and we are injecting it into patients, giving them the infection with the expectation that that infection will cure their cancer,” John Rothman, PhD, vice president of clinical development at Advaxis, said during the April 15 presentation. Listeria monocytogenes infect antigen-presenting cells, which consume foreign invaders and instruct the immune system to attack them.

In the phase-1/ phase-2 study, researchers divided patients into three groups of five. Each group received two doses of either 1 x 10⁹, 3.3 x 10⁹ or 1 x 10¹⁰ units of Listeria at three-week intervals. Patients were administered ampicillin five days after each dose, first intravenously and then orally for 10 days.

At study end, five patients progressed, seven patients had stable disease and one patient had a partial response. The patient with a partial response was pulled from the study to continue chemotherapy and undergo a radical hysterectomy; this patient is now tumor free with a performance status of 100%. Of the seven stable patients, three demonstrated tumor reductions of about 20%.

The most common adverse events were flu-like symptoms. Dose-limiting toxicities, in the form of severe flu-like symptoms, were seen at the highest doses; however, the vaccine was well tolerated in the low-dose groups.

Six of the 15 patients are still alive. The median survival as of March 3, 2008 was 194 days in those patients who died and 434 days in the remainder of patients. Overall median survival was 354 days. – by Leah Lawrence

Although it is still early days for this kind of treatment strategy, it appears as if it is safe, which is very important. This is an example of ingenuity in our field where we can take a fearsome infection and tame the beast by introducing novel genes to it that can turn it from a potentially lethal foe into an ally in the fight against cancer.

– Louis Weiner, MD

Director, Lombardi Comprehensive Cancer Center

For more information:

Rothman J. #225. Presented at: 2008 Annual Meeting of the American Association for Cancer Research; April 12-16, 2008; San Diego.