ASCO: Experimental vaccine made from frozen immune cells shows promise for prostate cancer patients

Metastatic prostate cancer patients who received an investigational vaccine made from their own frozen immune cells lived 10 months longer than those not treated with it, according to data being presented by researchers from the Kimmel Cancer Center at Jefferson at the 2011 American Society of Clinical Oncology annual meeting in Chicago on Saturday, June 4.

In an exploratory, multi-institutional analysis, researchers administered the vaccine APC8015F to a group of patients from the control arm of three randomized, Phase 3 clinical trials evaluating sipuleucel-T, a similar, FDA-approved cancer vaccine for metastatic castrate resistant prostate cancer.

APC8015F is made from immune system cells taken from a patient with prostate cancer; however, unlike sipuleucel-T, which is never frozen, APC8015F is cryopreserved at a time before the disease progressed.

Results from the analysis showed that patients treated with APC8015F had improved survival relative to the patients who were not treated in the control arm. Following disease progression, the median survival of patients treated with APC8015F was 20.0 months compared to 9.8 months for control patients.

"The study is important because it suggests that the sipuleucel-T therapy may have extended survival for a longer time than estimated in the clinical trials due to the beneficial effects of the frozen product on some men who initially received the placebo," said Leonard Gomella, M.D., Chair of Urology at Jefferson's Kimmel Cancer Center in Philadelphia. "Further, the clinical activity of the frozen-activated product is maintained."

Post-progression treatment with APC8015F, which is not FDA approved, may have extended survival of subjects, potentially reducing the magnitude of survival difference observed between sipuleucel-T and controls in randomized controlled trials.

Sipuleucel-T is FDA approved under the brand name Provenge to treat men with advanced prostate cancer that is asymptomatic or minimally symptomatic and no longer responding to hormonal therapy.