Protoxin, also called PRX302, is a drug being tested on men with localized recurrent prostate cancer in Phase I clinical trials in Texas and Vermont.

Patients considering this trial must have experienced recurrence after completing a full course of definitive external beam radiation or definitive brachytherapy (but not both) as primary therapy for diagnosed prostate cancer at least one year prior to enrollment

Our main news about Protoxin is here:
PSA-activated protoxin that kills prostate cancer: phase I clinical trial is underway

http://www.psa-rising.com/prostatecancer/protoxin1106.htm

A reader asked for a simpler, clearer explanation of what’s going on with this drug. Here’s what we know at the moment:

In Texas, one trial enrolled the first patients in May this year and is hoping to recruit 36 men with localized recurrent prostate cancer. Patients must have recurred after EBR or brachytherapy, have PSA level less than 20 ng/mL and PSA doubling time longer than 3 months. They must NOT be taking hormone drugs. Also, they must NOT have signs of metastatic disease including no bone metastases on bone scan, or any lymph node, lung, liver or soft tissue.

A link to info about that trial is here:

http://clinicaltrials.gov/ct/gui/show/NCT00379561?order=2

The 3 cancer centers so far are

1) Scott and White Cancer Center, Temple, Texas:

http://www.sw.org/sw/portal/_pagr/105/_pa.105/161

2) M. D. Anderson Cancer Center

3) University of Vermont (contact Dr. Mark Plante).

If you think you would want to be in this trial take this info to your doctor.

This Phase I trial aims to find out:

1) whether the drug is safe
2) whether it has side effects
3) whether it beats back the cancer.

So far they have reached the third “dose level” in testing the drug in the Temple, TX trial, which began in May and are moving forward to recruit more patients there and at the 2 other centers.

What they know so far is that PRX302 is activated (switched on) by PSA. It reduces the size of a prostate cancer tumor by destroying cancer cells. It does this by making a hole (or pore) in the cell membrane (the surface covering each prostate cancer cell).

PRX302 is injected into the prostate under ultrasound guidance.

PRX302 is expected to have fewer side effects than traditional or current systemic treatments because it is injected directly into the prostate.

The high level of PSA being produced by prostate cancer cells switches on the drug, the drug forms pores on the cell´s surface, and the cancer cells die.

This is the plan. Whether it will really work on men with localized recurrent prostate cancer, and whether it will keep working permanently or for a long time, no one will know for sure till the trial is further along and/or completed.

If it works reasonably well they will take it to a Phase II and then a Phase III clinical trial. Ultimately this might create a whole new treatment for men with early stage localized prostate cancer.

Another Phase I trial testing Protoxin for BPH (benign overgrowth of the prostate) is under way in Vancouver, Canada.