New trial of VTP for localized prostate cancer opens at five US centers

A media release from New York University Langone Medical Center, issued yesterday, has announced the initiation of a multi-center, Phase I/II clinical trial of vascular-targeted photodynamic therapy (VTP) in men with localized prostate cancer.

In this trial, about 30 patients with biopsy-proven, localized disease will initially be medicated with a photosensitizing agent called WST11 and then treated with VTP. Greater detail is available on the web site. In this procedure, laser fibers are positioned over the prostate where cancer cells have been identified. Once the laser fibers are correctly positioned, the WST11 is administered to the patient intravenously and circulates throughout the blood stream. The laser fibers are then activated to deliver a specific wavelength of light to the prostate. When the light comes into contact with the drug in circulation, the laser fibers supposedly destroy the blood vessels around the tumor, shutting down blood supply to the cancer. Patients are followed for a year after treatment with PSA tests after each visit and an MRI and needle biopsy performed at 6 months.

Specifically, treatment will consist of a single, 10-minute, IV administration of WST11 at doses of 2, 4, or 6 mg/kg, followed by either light activation delivered through transperineal interstitial optical fibers for 20 minutes using 753 nm laser light at escalating fixed energy doses of 200 J/cm or 300 J/cm by escalating power at each energy to 167 mW/cm or 250 mW/cm respectively. A brachytherapy-like template is used for the placement of the transparent implant catheters which are positioned in the prostate under transrectal ultrasound image guidance. The illumination fiber(s) are then inserted into the implant catheters.

A key objective of this trial is to compare patient outcomes based on the three different doses of WST11 and the two different doses of light energy. Patients can enroll in this trial at two centers in New York and at centers in Los Angeles, Atlanta, and St Louis, MO. Similar studies have already been carried out in some European countries or are currently under way.

According to Dr. Samir Taneja, the principal investigator for this clinical trial, “This minimally invasive technique for localized prostate cancer offers the potential to destroy the cancer without making any incision or causing any potentially devastating sexual, urinary or reproductive side-effects. … [It] only treats the cancerous part of the prostate gland, similar to how a lumpectomy might be done for breast cancer.”

5 Responses

  1. I’ve been waiting for this. Bookmarked!

  2. This is interesting and would be a nice substitute for the thalidomide I’ve been on twice to reduce the blood supply to the tumors. (I’ve used this for 6 and 8 months at the end of my second and third off-therapy periods to extend those periods.)

    However, I’m having a little trouble visualizing how this would work. I can easily understand a laser being able to do the job on blood vessels in its line of sight, but what about vessels obscured from direct view? Can the beam penetrate in a broadcast fashion for a centimeter or two? Is any collateral damage anticipated?

  3. Jim:

    The fact that they are testing three different doses of the WST11 and two different laser power levels makes me think that this has more to do with the synergistic interaction between the drug and the photons than either one alone.

  4. I have done enough research to have made a decision to seek vascular-targeted photodynamic therapy as a first choice method to address my localized prostate cancer (clinical stage T1c, PSA 6.2 ng/ml). I know this trial is ongoing and has been for some time. I would like to know if there are any facilities near Boston, MA, that might be offering this procedure currently.

    Thank you.

  5. Dear Richard:

    The trial referred to in this post was a small one, with a total enrollment of just 30 patients, and was fully enrolled some time ago. We know of no other trial currently enrolling patients for this type of therapy in North America, although there is a large Phase III clinical trial currently enrolling patients at centers in France and England.

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