Trelstar Depot (triptorelin pamoate)

The following drug information is obtained from various newswires, published medical journal articles, and medical conference presentations.

Approval Status:

Approved June 2000

Specific Treatments:

For the palliative treatment of advanced prostate cancer

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General Information

Trelstar Depot is indicated in the palliative treatment of advanced prostate cancer. It offers an alternative treatment for prostate cancer when orchiectomy or estrogen administration are either not indicated, or unacceptable to the patient.

Clinical Results

Following a single intramuscular (IM) injection of Trelstar Depot to healthy male volunteers, serum testosterone levels first increased, peaking on day 4, and declined thereafter to low levels by week 4. Similar testosterone profiles were observed in patients with advanced prostate cancer, when injected with Trelstar Depot. In healthy volunteers, testosterone serum levels returned to near baseline by week 8.

Trelstar Depot was studied in a randomized, active control trial of 277 men, ages 47 to 89, with advanced prostate cancer. The population consisted of 59.9% Caucasian, 39.3% Black, and 0.8% Other. There was no difference noted in relation to patient ethnicity. Patients were given either Trelstar Depot or an approved GnRH agonist monthly for 9 months. The primary efficacy results were both achievement of castration by Day 29 and maintenance of castration from Day 57 through Day 253.

Castration levels of serum testosterone were achieved in 91.2% of Trelstar Depot patients at Day 29 and 97.7% of patients at Day 57.

Side Effects

Trelstar Depot may cause the following side effects:

  • Fatigue
  • Nausea
  • Vomiting
  • Decreased blood cell counts
  • Hair loss
  • Mouth sores
  • Hot flushes
  • Loss of sexual drive
  • Breast tenderness
  • Nausea
  • Diarrhea

Mechanism of Action

Triptorelin is a potent repressor of gonadotropin secretion when given continuously and in therapeutic doses. Following the first administration, there is a transient surge in circulating levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone, and estradiol. After chronic and continuous administration, usually 2 to 4 weeks after initiation of therapy, a sustained decrease in LH and FSH secretion and marked reduction of testicular and ovarian steroidogenesis is observed. In men, a reduction of serum testosterone concentration to a level typically seen in surgically castrated men is obtained. Consequently, the result is that tissues and function that depend on these hormones for maintenance become quiescent. These effects are usually reversible after cessation of therapy.

Additional Information

Trelstar Depot may cause fetal harm if given to pregnant women.

For more information on Prostate Cancer, visit the American Cancer Society