The current role of sipuleucel-T in the management of advanced prostate cancer

A new review article has provided a detailed update on the current state of knowledge about the use of sipuleucel-T (Provenge®) in the treatment of advanced forms of prostate cancer.

The full text of this review article, by Hu et al., is available on line and will be a useful resource for prostate cancer educators and prostate cancer support group leaders. It will also make interesting reading for some patients with progressive forms of prostate cancer who are having to think about “what do I do next” when standard forms of androgen deprivation therapy stop working.

Hu and her colleagues at Duke University Medical Center take a very positive approach to the potential value of sipuleucel-T, whether it is being used in combination with ADT or used in combination with ADT and with other agents such as abiraterone acetate or enzalutamide. We should note that not all experts would necessarily be quite so positive about the value of this type of treatment, but these are very personal decisions, and the question of whether one’s insurance will cover the costs involved are clearly going to be a factor for most patients.

What Hu et al. have done for the reader is provide an excellent summary of all of the available data on the use of sipuleucel-T and of the ongoing clinical trials that involve the use of what — at present — is still the only immunotherapeutic agent that has ever been demonstrated to have a clinical impact on prostate cancer progression and survival in large, well-designed clinical trials.

Hu et al. state that, in their practice at Duke, they are currently using sipuleucel-T in two basic categories of patient:

  • Informed patients who have early, asymptomatic, metastatic, castration-resistant prostate cancer (mCRPC) with a low tumor burden and typically with a low PSA level (<20 ng/ml); these patients are then followed to monitor for disease progression.
  • Informed mCRPC patients with a rapidly rising PSA (i.e., a PSA doubling time of < 3 months), PSA levels > 50 ng/ml, minimally symptomatic disease, or a higher tumor burden; again, these patients would be followed for effects on disease progression and for any effects on PSA doubling time.

However, the authors also note that

 … we have increasingly administered sipuleucel-T in the context of additional hormonal therapy (either enzalutamide or abiraterone acetate) either concomitantly or immediately following.

It is clear today that the greatest current potential value of sipuleucel-T in the management of advanced forms of prostate cancer comes if it is used as soon as there is a clear indication of metastatic, castration-resistant disease  — which could be as little as clear evidence of a positive lymph node and a rising PSA in a man whose disease had previously been well controlled on standard forms of ADT. The implication is therefore that the use of newer forms of imaging in such patients to identify metastasis as early as possible may be critical to the earliest possible use of sipuleucel-T within its approved indication, i.e., “for the treatment of asymptomatic or minimally symptomatic metastatic castrate-resistant
(hormone-refractory) prostate cancer”.

The potential of sipuleucel-T much earlier, in the treatment of high-risk patients who are non-metastatic or not castration-resistant or both, is still limited by: (a) the lack of an approved indication for such use and (b) the very small amount of data available — from the NeoACT and the STAND studies, which are discussed in the full text of this paper.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: