Provenge or Sipuleucel-T (sip-T) remains not well understood by many prostate cancer survivors as well as some treating physicians. Because Provenge does not immediately control PSA or disease progression it creates a situation where some individuals are skeptical as to its efficacy. This is true despite the clear survival advantage demonstrated in clinical trials. This is even true despite the FDA and EMA having approved this treatment.

There is an ongoing multicenter Phase 4 registry trial called PROCEED active in the US. It enrolled prostate cancer survivors treated with commercial Provenge. The PROCEED trial is collecting information on chemotherapy treatments after Provenge treatment; these data will allow researchers and doctors to assess chemotherapy predictability and determine characteristics associated with time to beginning chemotherapy after having been treated with Provenge.

PROCEED has enrolled over 1,900 men who were treated with Provenge within the prior 6 months. Demographics, disease characteristics, and prior and ongoing prostate cancer treatments were recorded at baseline.

Additionally, data was also collected that characterized men who received chemotherapy after Provenge and used statistical modeling to identify predictors of time to a man’s first chemotherapy treatment.

As of May 2013, 1,254 enrolled men had completed Provenge. Time to their first chemotherapy session ranged from 0.4 – 19.2 months. Median time to first chemotherapy was shorter at oncology vs. urology practices (11.6 vs. 18.0 months, Kaplan-Meier method; HR= 2.154; p<0.001).The researchers found that men who are younger, have lower baseline hemoglobin, have higher baseline PSA, or who received prior chemotherapy, receive subsequent chemotherapy sooner.Thoughts

It is interesting that oncology practices started chemotherapy earlier than did the urologic practices. What we need is a follow up with these groups of men to see if there might be a survival advantage to either of these groups.

I have written that it is significantly advantageous to take Provenge as early as possible, ideally as soon as you become castrate resistant. This data confirms my assertion as we see that men with lower PSA scores and men who have not yet had any chemotherapy sessions faired better (as measured by a longer period of time needed to start chemotherapy than those at a later disease stage).

Clinical trial information: NCT01306890.

J Clin Oncol 32:5s, 2014 (suppl; abstr 5040); Christopher Michael Pieczonka, Raoul S. Concepcion, Ronald F. Tutrone, David F. Penson, James L. Bailen, Carl A. Olsson, John B. Forrest, Vahan Kassabian, Bryan A. Mehlhaff, Neal D. Shore, Raymond S. Lance, Robert Claude Tyler, Andrew Sandler, Candice McCoy, James Boyd Whitmore, Matthew R. Cooperberg;

Joel T Nowak, M.S.W. M.A.