Focused Prostate Cancer Drugs: Sophiris Bio and Steba Biotech

In the last decade, focal treatments for prostate cancer and BPH have appeared as an alternative to major prostate removal surgery.  Many of these use a minimally invasive surgical technique to ablate portions of the prostate.  These may use cryo (cold), laser (heat), HIFU (heat/ultrasound), NanoKnife (electrical) or radio frequency (heat) techniques to kill localized tumors and surrounding tissue.  Some of these techniques are already approved in the United States, while others are available in Europe, Mexico or other countries.

In the last few years, companies have also developed focused drug delivery systems to treat BPH and/or Prostate Cancer.  These include  PRX302 from Sophiris Bio and TOOKAD from Steba Biotech.

PRX302 (Topsalysin) has already completed a Phase III trial in the USA for treating BPH, or Benign Prostatic Hyperplasia (prostate enlargement).  It recently competed a Phase IIa trial for treating localized PCa, or Prostate Cancer.  It has just started a Phase IIb trial in the USA for PCa.  Topsalysin is injected into the prostate to minimize affects on other areas of the body.  It is activated by PSA, made only by prostate cells.  Once activated, it causes death of affected prostate and prostate cancer cells.  Sophiris Bio is based in Canada and trades on the NASDAQ as SPHS.

TOOKAD® (Padeliporfin) is also injected directly into the prostate in low risk, localized prostate cancer patients.  It recently completed Phase III trials in Europe and in Latin America and is now available in Mexico.  Once injected, near-infrared light is applied to the tumor, activating the drug and releasing toxins that destroy surrounding blood vessels and cancerous cells.  Steba Biotech is based in Luxembourg, France and Israel and is privately owned.

The traditional treatment for prostate cancer, radical prostatectomy, removes the entire prostate along with a section of the urethra and the internal sphincter that is used in the process of urination and ejaculation.  Obviously, this kind of major surgery has possible side effects involving sexual function, urinary continence, infection and even damage to the rectum.  Localized focal treatments generally reduce or avoid these risks and may even be performed on an outpatient basis.  The disadvantage is that they may not offer as high of a cure rate for the cancer, since some of the prostate may be left intact .  Fortunately, many of these focal treatments can be repeated or followed by a radical prostatectomy, if necessary.