Immunotherapy

Biological therapy is referred to by many terms, including immunologic therapy, immunotherapy, or biotherapy. Biological therapy is a type of treatment that uses the body’s immune system to facilitate the killing of cancer cells. Types of biological therapy include interferon, interleukin, monoclonal antibodies, colony stimulating factors (cytokines), and vaccines.  Biologic therapies are being developed for the treatment of prostate cancer.  Sipuleucel-T( Provenge®)  is an immunotherapy that prompts the body’s immune system to respond against the cancer, and was the first to be approved by the FDA.

Sipuleucel-T is an immunotherapy that prompts the body’s immune system to respond against the cancer. A Phase III clinical trial that contributed to the FDA approval of Sipuleucel-T was a study known as IMPACT (IMmunotherapy for Prostate AdenoCarcinoma Treatment). The results of this study were presented at the 2010 Genitourinary Cancers Symposium, and the final results were published in The New England Journal of Medicine.

To evaluate the effect of Sipuleucel-T among men with metastatic, androgen-independent prostate cancer, researchers conducted a Phase III clinical trial known as IMPACT (IMmunotherapy for Prostate AdenoCarcinoma Treatment). The trial enrolled 512 men. Study participants were treated with either Sipuleucel-T or a placebo and then directly compared. Median overall survival was 25.8 months among men treated with Provenge compared with 21.7 months among men treated with placebo.

  • Three-year survival was 31.7% among men treated with Sipuleucel-T compared with 23% among men treated with placebo.
  • Sipuleucel-T did not significantly delay cancer progression.
  • Side effects of Sipuleucel-T included chills, fever, and headache. Most of these side effects were low grade and of short duration.

The results of the study demonstrate that immunotherapy can be used in the management of prostate cancer; Sipuleucel-T improved overall survival among men with metastatic, androgen-independent prostate cancer.

Strategies to Improve Treatment

The progress that has been made in the treatment of prostate cancer has resulted from development of better treatments that were evaluated in clinical studies. Future progress in the treatment of prostate cancer will result from patients continued participation in appropriate clinical trials. Developing novel immunotherapies is an area of active investigation.

Earlier Use: Immunotherapy appears to work best when used to minimal amounts of caner. Using Sipuleucel-T before cancer becomes hormone refractory may potentially improve outcomes with this therapy and is being evaluated.

Novel Immunotherapies: Novel vaccine strategies to harness the immune system are being tested, such as PROSTVAC in asymptomatic, chemotherapy-naïve men prostate cancer Other immune based strategies include inhibition of immune check points using Ipilimumab, which is a monoclonal anti-CTLA4 antibody that binds to a receptor on T cells, blocking CTLA4 and, in turn, activating T-cell anti-tumor activity.

Reference:

Kantoff PW, Higano CS, Shore ND, et al. Sipuleucel-T immunotherapy for castration-resistant prostate cancer. New England Journal of Medicine. 2010;363:411-422.

Kantoff P, Higano CS, Berger ER, et al. Updated survival results of the IMPACT trial of sipuleucel-T for metastatic castration-resistant prostate cancer (CRPC). Presented at the 2010 Genitourinary Cancers Symposium in San Francisco. March 5-7, 2010. Abstract #8.