Androgen blockades come in many different configurations. One of these configurations known as monotherapy, or ADT1, involves using only the drug Bicalutamide (Casodex).

The most common androgen blockade (ADT2) involves using Bicalutamide along with an agonadotropin releasing hormone (GnRH) agonists (i.e. Lupron and Leuprolide). Some men also add a third drug (ADT3), Adovart or Proscar.

ADT2 and ADT3 cause significant side effects as it stops the production of sex hormones (testosterone). This often causes loss of bone density, hot flashes, weight gain, depression and confusion etc. ADT1 does not stop the production of the hormones, but instead blocks the hormones ability to bind with the cell’s receptors and feed the prostate cancer.

In the July issue of the Journal of Clinical Oncology, researchers from the Massachusetts General Hospital (MGH) describe a very small study they performed using only Bicalutamides (ADT1). The study subjects had improved bone density and reported fewer unpleasant side effects than did those on ADT2. The study subjects on ADT1 maintained hormone levels in their blood stream and demonstrated dramatic increase in bone density while the ADT2 group lost bone density.

Earlier research has shown that ADT1 alone is as effective as ADT2 for men with locally advanced prostate cancer.

This small study included only 51 men with nonmetastatic prostate cancer who were randomly assigned to receive either ADT1 or ADT2 for one year. The subjects knew which treatment they received, as the drugs are administered differently. The researchers who gathered and analyzed the data were blinded, they did not know which patients were in which group.

At the end of the study period, blood levels of testosterone and the female hormone estradiol had risen significantly in the ADT1 group but fallen in those receiving ADT2. Bone mineral density decreased in the ADT2 group, but increased in the ADT1 group. Both groups had increases in body fat but the changes were more pronounced in the ADT2 group. The negative side effects were significantly lower in the ADT1 group.

ADT1 might an attractive alternative to ADT2 and ADT3 for men with non-metastatic prostate cancer. ADT1 is currently approved as monotherapy for prostate cancer in 55 countries, however, in the U.S., it is only approved in combination with GnRH-analog therapy.

Joel T Nowak MA, MSW