A Phase III clinical trial of PROSTVAC-VF may be in the offing


According to a story on ScienceDaily today, investigators are continuing to plan for a Phase III clinical trial of PROSTVAC-VF — a poxvirus-based prostate cancer “vaccine” — in men with castration-resistant prostate cancer (CRPC).

This story comes out in conjunction with the publication of data from the Phase II clinical trial of PROSTVAC-VF that was presented at the ASCO annual meeting last year. For our original summary of the results of that trial see our earlier report on these data from the ASCO meeting.

At the time of that report, Therion Biologics, the US developer of PROSTVAC-VF, had stated that they were in discussions with the Eastern Cooperative Oncology Group (ECOG) about the development  of an appropriate Phase III trial. However, all rights to the development of PROSTVAC-VF are now controlled by Bavarian Nordic, and additional information about the product can be found on that company’s web site.

To date, only one prostate cancer “vaccine” (sipuleucel-T/Provenge) has actually demonstrated a survival benefit in the treatment of men with CRPC in a randomized, double-blind, multicenter, Phase III clinical trial. Should PROSTVAC-VF also be able to demonstrate such a benefit, this would further establish the potential of immunobiologics in the treatment of cancer in general and prostate cancer in particular. In the Phase II trial data reported in the Journal of Clincial Oncology and presented at ASCO, PROSTVAC-VF provided an 8.5-month survival benefit compared to placebo, which is approximately twice the survival benefit demonstrated by sipuleucel-T.

14 Responses

  1. Is the PROSTVAC-VF vaccine already to buy. And if yes, I would like to know, if there is a chance to buy it in Central America (Costa Rica). Thank you for your answer. Sonja

  2. Dear Sonja:

    No. I am sorry. PROSTVAC-VF is still an experimental therapy, and no one can buy at anywhere in the world yet. It coulkd be at least a couple of years before this product is available for physicians to prescribe for patients.

  3. Who do I contact to invest in the private company (Therion or BN?)?

    Contact info? Will they go public soon? Additional info?

    Thank you
    John

  4. Dear Mr. Walker:

    We regret that neither The “New” Prostate Cancer InfoLink nor Prostate Cancer International provides investment-related services.

  5. I keep finding articles such as this one which talk about “promising” trials of new medicines that are not available for years to come.

    Is there a list of “promising” medications or just all the existing meds used for prostate cancer treatment that are actually available right now anywhere on your site? I need to learn about alternatives as it seems no one doctor I see knows about every option.

    Thanks,

    Nick

  6. Dear Nick:

    I am not aware that anyone has such a complete list. Maybe I should see if I could compile one. The problem is that different drugs work at different disease stages.

    What I can easily tell you is that the following drugs are currently awaiting approval, in Phase III clinical trials for the treatment of advanced forms of prostate cancer, or expected to enter such trials in the near future:

    — Adenovirus-based “suicide” gene therapy in combination with radiation therapy for the first-line treatment of intermediate risk, localized prostate cancer.

    — Sipuleucel-T (Provenge), which has completed its registration trials and which people hope will be approved by the US FDA in May or June this year.

    — Dasatinib (Sprycel), which is in Phase III clinical trials in combination with docetaxel + prednisone for the treatment of patients with hormone-refractory prostate cancer.

    — Lenalidomide (Revlimid), which is in Phase III clinical trials in combination with docetaxel + prednisone for the treatment of patients with hormone-refractory prostate cancer.

    — Bevacizumab (Avastin), which is in Phase III clinical trials in combination with docetaxel + prednisone for the treatment of patients with hormone-refractory prostate cancer.

    — Sunitinib (Sutent), which is in Phase III clinical trials in combination with prednisone for the treatment of patients who have relapsed after at least one round of docetaxel-based chemotherapy.

    — Abiraterone acetate, which is in Phase III clinical trials for the treatment of (a) patients who have relapsed after at least one round of docetaxel-based chemotherapy and (b) patients who have hormone-refractory prostate cancer but who have not received chemotherapy.

    — Atrasentan (Xinlay), which is in Phase III clinical trials in combination with docetaxel + prednisone for the treatment of patients who have hormone-refractory prostate cancer.

    — Alpharadin (injectable radium-233), which is currently in Phase III trials for the treatment of patients with symptomatic, metastatic, hormone-refractory prostate cancer and skeletal metastases.

    — ZD4054, which is in Phase III trials for the treatment of (a) patients who have hormone-refractory prostate cancer with evidence of gross metastasis and (b) patients who have hormone-refractory prostate cancer with no evidence of gross metastasis.

    — MDV3100, which has just started Phase III trials for the treatment of patients who have relapsed after at least one round of docetaxel-based chemotherapy.

    — OGX-011, which should shortly start Phase III clinical trials in combination with docetaxel and prednisone for patients who have relapsed after at least one round of docetaxel-based chemotherapy.

    — Ipilimumab, which should shortly start Phase III clinical trials in patients with symptomatic or minimally symptomatic, chemotherapy-naïve, castration-resistant prostate cancer.

    — PROSTVAC-VF, which is apparently in the planning stage for Phase III trials for patients with metastatic hormone-refractory prostate cancer (as specificed above).

    I think that is everything in late stage clinical trials that is not already approved for treatment of advanced prostate cancer. If I have missed anything, I apologize.

  7. With cancer, in this case prostate cancer, why is it that after a primary treatment most all chemotherapy or virus or anti angiogenesis is initiated after tumors are rediscovered? PSA may be zero, but not in a significant quantity (reflecting cancer volume) to initiate treatment. Why not prophylactically treat it’s potential while it may be much smaller and treatable with more success?

    Thank you,

  8. Dear RM:

    Some cancers can be treated successfully just as you describe. For example, many blood cancer patients may receive initial targeted chemotherapy followed by long-term maintenance chemotherapy to reduce the likelihood of recurrence. Blood cancers by their very nature are commonly disseminated cancers from the time they are found, and may need this type of therapy.

    In the case of solid tumors, however, the initial treatment is commonly surgical or some other form of therapy designed to eliminate what is believed to be a localized tumor (e.g., cancer that is entirely confined to the prostate). Such tumors are very commonly treated successfully by simply removing the cancerous organ or tissue. Following such treatment, there is no apparent sign of cancer, and so there is nothing to treat.

    Giving someone who might already be cured a year’s worth of hormone therapy or several cycles of chemotherapy would actually be dangerous. It is therefore appropriate practice to monitor the patient with care and re-treat them only when there is a clear and early signal of recurrence.

    Having said that, there are most certainly higher-risk patients with solid tumors who do receive adjuvant long-term treatment to accomplish exactly what you are describing. A man initially diagnosed with high-risk prostate cancer might receive initial surgery to remove his prostate followed by a combination of external beam radiation to his pelvis and 2 or 3 years of hormone therapy to maximize the chance of complete remission. Similarly, a friend of mine with a high-risk form of sarcoma in her leg received initial chemotherapy and radiation followed by surgery to remove the dead tissues and is now in complete remission.

  9. Thank you for the informative resoponse. PROSTVAC-VF vaccine is an example of something with a low side effect profile.

    Do you think this is just the process of determining the effectiveness of a therapy by taking on a disease once it’s gained significant momentum rather than before or even prophylactically while the cancer may be less differentiated and or more susceptible to therapies?

    I believe this poxvirus would be one to watch for all men at risk of any recurrence. The immune response may be even more effective with low volume solid tumors.

  10. Dear RM:

    To date, PROSTVAC-VF has only been tested in a relatively small number of men with metastatic, castration-resistant prostate cancer — men who were also receiving androgen deprivation therapy (ADT) as well as the investigational vaccine.

    There is a lot which, as yet, we don’t know about PROSTVAC-VF. It does indeed appear to have a relatively low risk for side effects — based on data available to date. There is also little doubt that within the next few years we can expect to see trials of a number of prostate cancer “vaccines” in much earlier stages of the disease. Whether they will be able to radically change the course of prostate cancer when given earlier in the disease state is completely unknown at this time, but an awful lot of people are hoping this will be the case.

  11. Dear Sirs:

    I would like to have the news letter (by e-mail) from you. I am interested in new prostate cancer trials.

    Best regards,

    Jerzy

  12. Dear Jerzy:

    We do not produce an actual newsletter, but you can receive introductions to all the news we produce directly on your computer if you sign up for the RSS feed service. To do this, first click here; then click on the link that says, “Subscribe to this feed.”

  13. I am 3 years post-prostatectomy, and in the last 6 months my PSA has started to creep up from 0.05 to 0.5 ng/ml so I am anxiously casting around for what I can do, considering everything and anything. I am at the same time excited and suspicious when I read websites of eg Issels clinics, and all their success reviews. Can they be real, truthful, and as successful as they claim?

  14. Some of the types of treatment used at the Issels clinics are based on science that does indeed appear to have a valid foundation. Indeed, the only FDA-approved cancer “vaccine” is one that is based on stimulation of the activity of dendritic cells. However, I am aware of no independent data validating the methods used at the Issels clinics in the treatment of prostate cancer.

    If your PSA has risen from 0.05 to 0.5 ng/ml within 6 months, you should be thinking seriously about your next step because you clearly have a rapid PSA doubling time and you are increasing the potential risk that your cancer might metastasize way beyond the pelvic region if you do not take action in the reasonably near future. Standard therapy for someone like you would normally be external beam radiation therapy to the pelvic region around the prostate, possibly in combination with a period of hormone therapy.

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