The prostate cancer vaccine sipuleucel-T (Provenge) is the first T-cell-driven immunotherapy that has received U.S. Food and Drug Administration (FDA) approval. As the leader of the clinical trials for Provenge at Seattle Cancer Care Alliance (SCCA) over a span of more than 15 years, Celestia S. Higano, MD, played a key role in the development of the vaccine. She continues as lead investigator in the PROCEED Registry, which tracks patient outcomes and immune changes after treatment with Provenge.
Provenge is considered a “therapeutic vaccine” because it is given to men who already have prostate cancer. It is produced by removing some of the patient’s own immune cells and exposing them directly to an antigen that is present on over 95 percent of prostate cancer cells and stimulating the immune cells with a cytokine. The product contains activated T-cells that are reinfused into the patient two days later. These activated cells further initiate an immune response in the patient. In the pivotal clinical study of the vaccine, men with no or minimal symptoms with metastatic castration resistant prostate cancer survived 19 percent longer than those who did not receive it.
Other therapeutic vaccines are designed to protect patients with cancers that are likely to recur. Mary “Nora” Disis, MD, leads the effort at SCCA to develop a vaccine that could prevent relapses in patients with breast or ovarian cancer where up to 30 percent of women diagnosed with invasive breast cancer will have recurrences within five years, and 80 percent of women treated for ovarian cancer will relapse after the initial treatment.
What to Expect
Administering Provenge is relatively non-invasive for patients and takes only four to six weeks to complete. First, the patient’s white blood cells are collected in a process called leukapheresis. The white blood cells are express-shipped to a facility where they are co-cultured with a prostate cancer antigen linked to an immune stimulant. After about 40 hours, the cells are washed, tested for cell counts, immune activity, and sterility. The final product is Provenge. On the third day after leukapheresis, the patient returns to have Provenge administered intravenously, similar to a blood transfusion. This process is repeated every two weeks for a total of three infusions.
Typically, the side effects are mild. Like traditional vaccines, immunotherapy vaccines may be associated with side effects that commonly include low-grade fever and chills that last for a few days and then disappear. This is outpatient treatment. Patients who come to the SCCA from outside the United States to receive Provenge should plan to stay in the Seattle area for a total of six to eight weeks for appropriate consultation and scheduling of the leukapheresis procedures.