Prostate Cancer

Antiandrogens

 

An antiandrogen is a compound that blocks androgen action at the level of the androgen receptor and inhibits the growth of prostate cancer cells. Endoceuticsä research is focusing on developing a potent and pure antiandrogen to fight prostate cancer. The first treatment of prostate cancer to prolong life has been developed by Endorecherche, the mother company of Endoceuticsä.

Prostate cancer is the second leading cause of cancer deaths in men with 220,800 new cases to be diagnosed and 27,540 deaths estimated to occur in the United States alone in 2015 (American Cancer Society, 2015). Although improvements in surgery and radiotherapy have occurred, National Cancer Institute data from 2.1 million patients with cancer in the USA between 1975 and 1995 have led to the conclusion that “cancer-fighting drugs improved survival rates, especially for cancer of the prostate, where drug innovations have been the greatest” (Lichtenberg 2002).

In prostate cancer therapy, the most important drugs have been gonadotropin-releasing hormone (GnRH) agonists (Labrie, Bélanger et al. 1980) and pure antiandrogens (Neri, Monahan et al. 1967) permitting the co-administration of a pure antiandrogen with medical or surgical castration in order to achieve combined androgen blockade (CAB) simultaneously at start of treatment (Labrie, Dupont et al. 1982; Labrie, Dupont et al. 1985). However, despite significant improvements in diagnosis and treatment, prostate cancer remains the second most common cause of death after lung cancer in American men (American Cancer Society, 2015). Most importantly, since prostate cancer is the most sensitive of all cancers to hormone therapy, every effort should be made to take advantage of this unique characteristic (Labrie 2011).

A paradigm changing discovery is that approximately 50% of androgens are produced by the testicles while a comparable amount is produced locally in the prostate from circulating DHEA. (Labrie, Dupont et al. 1982; Labrie, Dupont et al. 1985; Labrie F., Nature Reviews 8, 73-80, 2011). In 1980, it was discovered that medical castration is easily achieved in men by chronic administration of GnRH agonists (Labrie, Bélanger et al. 1980). Although GnRH agonists rapidly became the standard treatment worldwide to eliminate testicular androgens, early biochemical studies performed with human prostatic tissue have demonstrated that androgens were also synthesized in the prostate by the mechanism of intracrinology (Labrie 1991; Labrie, Bélanger et al. 2005) from dehydroepiandrosterone (DHEA), a precursor of sex steroids produced by the adrenal glands (Labrie, Dupont et al. 1985; Bélanger, Bélanger et al. 1989; Labrie, Simard et al. 1989; Labrie 1991; Labrie 2008b; Labrie, Cusan et al. 2009; Labrie 2010). With this well demonstrated information, the scientifically based logical follow-up is to use CAB to achieve appropriate blockade of the two sources of androgens (Labrie, Dupont et al. 1985) and to develop blockers of androgen formation and/or action having the highest possible inhibitory potency.

Treatment of Prostate Cancer

The first treatment shown to prolong life in prostate cancer, namely combined androgen blockade (CAB) or combination of castration with an antiandrogen, has been developed by the mother company Endoresearch under the direction of Dr. Fernand Labrie, also founder of Endoceuticsä.
The most urgently needed drugs in prostate cancer are more potent blockers of the androgen receptor and highly potent inhibitors of androgen biosynthesis in peripheral tissues. The advantage of antiandrogens is that they theoretically block the action of all androgens originating from any source instead of blocking only specific pathways of androgen formation. Endoceuticsä compounds are potentially much more potent than the available antiandrogens.

Antiandrogens are currently in Phase I/II of their development.

Mechanism of Action

The two sources of androgens (testes and adrenals) need to be blocked for an optimal treatment of prostate cancer.

Highlights of Antiandrogen Action in Prostate Cancer

  • Combined androgen blockade is the first treatment shown to prolong life in prostate cancer and was developed by the founder of Endoceuticsä.
  • A highly potent antiandrogen could potentially permit to cure localized prostate cancer in a shorter period than the 7 years needed with the available antiandrogens.
  • Resistance to combined androgen blockade does not occur or is very rare in localized disease.
  • More than 90% of localized cancers can be cured by combined androgen blockade.