Prostvac + ipilimumab shows promise in management of mCRPC

Results from a small trial of Barvarian Nordic’s investigational drug Prostvac — used in combination with Bristol-Myers Squibb’s ipilimumab (Yervoy) — appear to have shown relatively dramatic effects in the treatment of men with metastatic, castration-resistant prostate cancer (mCRPC).

The early-stage Phase I trial reported by Singh et al. and conducted the U.S. National Cancer Institute enrolled just 30 patients. However, on average, the patients taking both drugs survived for 31.3 months, compared with a predicted survival period of 18.5 months based on historical survival data for older chemotherapy treatments. In addition, of the 15 patients who received the highest dose of ipilimumab (10 mg) in combination with Prostvac, 20 percent remained alive at 80 months (yes, that is nearly 7 years).

These data, reported at the ongoing Genitourinary Cancers Symposium in Orlando, are obviously very preliminary and still need to be confirmed in larger, prospective, randomized trials. However, they clearly seem to show further promise related to the use of immunotherapeutic agents in the management of progressive forms of prostate cancer.

The abstract by Singh et al. also reports data from two other Phase II trials. In one of those two studies, 125 men with mCRPC were randomized 2:1 to receive Prostvac or placebo; the patients treated with Prostvac had improved overall survival compared to placebo (25.1 vs 16.6 months; hazard ratio [HR] = 0.56). In the second Phase II study, 32 patients with mCRPC treated with Prostvac had a median overall survival of 26.6 months (compared to a predicted median overall survival of 17.4 months).

6 Responses

  1. As a younger, advanced prostate cancer guy, it’s encouraging to read results like this. Hopefully I will be able to take advantage of drugs and therapies like this in the future so I can become an older, advanced prostate cancer guy.

  2. The phase I trial referred to here appears to be this one — that started in 2005 and first reported results in 2012.

    Thus the long-term report includes those men who were able to stay alive to benefit from sipuleucel-T, cabazataxel, abiraterone, enzalutimide, radium 223, docetaxel, and whatever else could be used. The extended survival is likely due, in part, to the study drugs. But only in part.


    Thanks again for reporting this news about these promising agents.

    I was especially interested to see if any safety and tolerance results were reported for Ipi, which is known to pose the risk that comes with turning off the immune system checkpoints that prevent the immune system from overreacting and doing unacceptable injury to the patient. The clinical trial site indicates that several types of safety data were collected, but none were reported. I’m thinking that means there were no major issues, but it would be good to know. I suspect the data have not been reported.

  4. I agree “Tarhoosier” — 100%. Of course there will algorithms for sorting out possible ‘interventions’ but their accuracy can only be confirmed if none of the interventions are ever taken!

    I am currently in the Phase III Prostvac trial and have the same concern if at the end of the trial I resort to enzalutamide, etc., due to a worryingly high PSA. After three injections (of seven) my PSA is certainly still rising at an “uncomfortable” rate — doubling time just 62 days.

    I have reason to believe I am receiving a “live” injection because although low, my doubling time has improved from its previous 45 days and I can see no other reason to cause this.

  5. Graham,

    Do you know at this point if you received the “live injection” and how are you doing?



  6. Not officially but 99.9% certain I was on the placebo arm.

    My PSA rose alarmingly until the end of the trial, when I started enzalutamide, which has brought it down to quite a bit less than half it’s zenith in the 2 months I have taken it.

    Many thanks for your interest.


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