Histrelin: in advanced prostate cancer

Area of Science:

• Oncology
• Endocrinology
• Pharmacology

Background:

• Advanced prostate cancer treatment often requires androgen deprivation therapy.
• Gonadotropin-releasing hormone (GnRH) agonists are a key component of androgen deprivation.
• Histrelin is a GnRH agonist delivered via a subcutaneous implant.

Purpose of the Study:

• To evaluate the efficacy and tolerability of a subcutaneous histrelin implant in patients with advanced prostate cancer.
• To assess the sustained suppression of testosterone, luteinizing hormone (LH), and prostate-specific antigen (PSA).

Main Methods:

• Two Phase II/III clinical trials were conducted.
• A noncomparative, multicentre, Phase III study utilized a histrelin acetate 50 mg implant.
• Serum hormone levels (testosterone, LH) and PSA were monitored over a 1-year treatment period.

Main Results:

• The histrelin implant achieved sustained testosterone suppression to castrate levels (< or =50 ng/dL) within 4 weeks in all patients.
• 99-100% of patients maintained castrate testosterone levels for the entire year.
• No acute testosterone or LH surges were observed upon implant replacement, and hormone suppression was maintained.
• The implant was generally well tolerated, with no treatment discontinuations due to adverse events.

Conclusions:

• The subcutaneous histrelin implant provides sustained and effective suppression of testosterone, LH, and PSA in advanced prostate cancer.
• Efficacy is maintained irrespective of patient age or disease stage.
• The histrelin implant is a well-tolerated treatment option for long-term androgen deprivation therapy.