Provenge For Early Stage Prostate Cancer
Provenge for early stage prostate cancer is not the approved use of this drug. In fact, when the immunotherapy Provenge (sipuleucel-T) was approved by the Food and Drug Administration (FDA) in 2010, it was approved for treatment of late stage prostate cancer. Specifically, it is for men with asymptomatic or minimally symptomatic metastatic prostate cancer that had not responded to hormone therapy. Because of the encouraging survival results achieved in the clinical trials in men who used Provenge and the immune system boost provided by the treatment, a growing number of experts and others have suggested the use of Provenge for early stage prostate cancer, or healthy men with prostate cancer.
It seems to make sense to offer Provenge at for early stage prostate cancer, because the immune system is better able to respond to the immune-boosting advantages of immunotherapy. Under the current guidelines, Provenge is offered only to men whose immune system is likely compromised because of previous treatment with hormone therapy.
The results of several studies support the effort to get approval for use of Provenge for early stage prostate cancer, and a brief overview of them is presented here. It also should be noted that the maker of Provenge, Dendreon, is currently planning a large Phase III study that will explore the use of the drug at an earlier phase of prostate cancer, with the hope of eventually getting FDA approval for such an indication.
But several small, preliminary trials have already looked at the effect of Provenge for early stage prostate cancer. For example:
- A Phase II trial was conducted that included 42 men with localized prostate cancer who were scheduled for radical prostatectomy. All completed the three-infusion course of Provenge less than 2 months before surgery. The men were followed for 72 weeks. A report on 19 patients, which was given at the 2012 Genitourinary Cancers Symposium, indicated a “robust immune system activation,” suggesting more research is needed to determine the potential benefits of Provenge in men with earlier stage prostate cancer. An important finding of this study, according to Leonard G. Gomella, MD, chair of the conference program committee at the American Society of Clinical Oncology symposium, was the presence of tumor markers, which allow clinicians to evaluate the impact of treatment. Gomella explained that it was “very positive news that this study was able to show that there were specific markers of an immune response in the prostate.”
- An additional analysis of this Phase II trial looked at the ability of Provenge to cause T cells (immune system cells that fight infection) to enter the tumor. Sipuleucel-T was associated with a greater than threefold increase in mean total T cells, T helper cells, and cytotoxic T cells, indicating Provenge can modulate the immune cells in prostate cancer tissue.
- Analysis of data from the Phase III IMPACT trial, which is the study that lead to FDA approval of Provenge, found that men who had indicators of less advanced disease, such as lower baseline prostate-specific antigen (PSA) and lactate dehydrogenase (an indicator of prostate cancer), tended toward a stronger treatment response, suggesting that giving Provenge earlier may result in better survival outcome.
At this point, it is uncertain whether the FDA will approve Provenge for early stage prostate cancer. Men who are interested in Provenge should discuss their options with their healthcare providers.
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Fong L et al. Immune responses in prostate tumor tissue following neoadjuvant sipuleucel-T in patients with localized prostate cancer. J Clin Oncol 2012;30:(suppl 5). Abstr 181.
Fong L et al. Neoadjuvant sipuleucel-T in localized prostate cancer: Effects on immune cells within the prostate tumor microenvironment. J Clin Oncol 2012;30(suppl; abstr 2564).
Sheikh NA et al. Evaluation of immune activation following neoadjuvant sipuleucel-T in subjects with localized prostate cancer. J Clin Oncol 2012;30(suppl; abstr 2563).