Aromatase inhibition: 4-hydroxyandrostenedione (4-OHA, CGP 32349) in advanced prostatic cancer
J H Davies1, M Dowsett, S Jacobs
1Department of Urology, St Georges Hospital, Tooting, London, UK.
Abstract:
We report the use of the steroidal aromatase inhibitor, 4-hydroxyandrostenedione (4-OHA, CGP 32349), in the management of patients with advanced, hormone resistant, prostatic cancer. Eighteen of 25 patients (72%) showed a subjective response, mainly in the form of pain relief and increased performance. There were no objective improvements. A tumour flare occurred in 17/25 (68%). Detailed endocrine studies were performed during treatment. These showed that suppression of serum oestradiol levels occurred in 19/25 (76%) of patients during treatment with 4-OHA. Serum levels of androstenedione increased in 9/14 patients (64%). Concentration of serum testosterone and 5 alpha-dihydrotestosterone were elevated in 3/14 (21%) and 2/11 (18%) patients respectively. There appeared to be no correlation between response or tumour flare and changes in steroid levels during treatment with 4-OHA. The mechanism of action of 4-OHA in palliating patients with advanced prostatic cancer remains obscure. 4-OHA or its metabolites may be acting on metastatic bone metabolism via effects on oestrogen related osteoclastic and osteoblastic activity. Further investigation of the effects of aromatase inhibitors on prostatic biology, and bone metabolism in patients with metastatic prostate cancer, would appear worthwhile.
Insights
The steroidal aromatase inhibitor 4-hydroxyandrostenedione (4-OHA) offered subjective benefits like pain relief in advanced prostate cancer patients. However, objective improvements and a clear mechanism of action for this hormone-resistant cancer treatment remain elusive.
Area of Science:
- Endocrinology
- Oncology
- Pharmacology
Background:
- Advanced, hormone-resistant prostate cancer presents significant management challenges.
- Hormonal therapies are a cornerstone of prostate cancer treatment, but resistance develops.
- Aromatase inhibitors are explored for their potential in hormone-refractory malignancies.
Purpose of the Study:
- To evaluate the efficacy of 4-hydroxyandrostenedione (4-OHA) in patients with advanced, hormone-resistant prostate cancer.
- To assess the endocrine effects of 4-OHA treatment in this patient population.
- To investigate the potential mechanisms of action of 4-OHA in palliative care for prostate cancer.
Main Methods:
- A clinical study involving 25 patients with advanced, hormone-resistant prostate cancer.
- Administration of the steroidal aromatase inhibitor 4-hydroxyandrostenedione (4-OHA).
- Monitoring of subjective and objective patient responses, tumor flare, and detailed endocrine profiles (steroid levels).
Main Results:
- Seventy-two percent (18/25) of patients reported subjective improvements, primarily pain relief and enhanced performance.
- No objective tumor responses were observed in any patients.
- Tumor flare occurred in 68% (17/25) of patients; 76% (19/25) showed suppressed serum estradiol levels.
- Changes in androstenedione, testosterone, and 5 alpha-dihydrotestosterone levels were variable and showed no clear correlation with patient response or tumor flare.
Conclusions:
- 4-hydroxyandrostenedione (4-OHA) demonstrates palliative effects in advanced prostate cancer, offering subjective relief but lacking objective tumor regression.
- The precise mechanism by which 4-OHA exerts its palliative effects in hormone-resistant prostate cancer remains unclear.
- Further research into aromatase inhibitors' impact on prostate cancer biology and bone metabolism is warranted, particularly in metastatic disease.
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