The GnRH agonist triptorelin has been used successfully for some time in various areas, including the treatment of hormone-dependent prostate cancer. The drug is now also approved for adjuvant therapy of hormone receptor-positive early breast cancer and will be reimbursed by health insurers from December 1, 2020.
A further development of gonadorelin, triptorelin (Pamorelin®) is a more potent agonist of gonadotropin-releasing hormone (GnRH) with increased affinity for pituitary receptors and slower inactivation in target tissues. Continuous dosing of the substance causes a decrease in plasma LH/FSH levels as well as in the sex hormones testosterone, estrogen, and progesterone. Thus, chemical castration can be achieved by monthly intramuscular injection of Pamorelin® 3.75 mg. Alternatively, there are formulations of 11.25 mg for three-monthly injection and 22.5 mg for six-monthly administration.
Until now, Pamorelin® was approved in Switzerland for the treatment of advanced hormone-dependent prostate cancer and endometriosis, as well as for downregulation in the context of assisted reproductive medicine. Now the drug may also be used in the dosage of 3.75 mg for the adjuvant therapy of hormone receptor-positive early breast cancer. Prerequisites include a high risk of recurrence, confirmation of premenopausal status after chemotherapy, and concomitant administration of tamoxifen or an aromatase inhibitor. In the pivotal studies, the addition of Pamorelin® to tamoxifen treatment was shown to significantly prolong both overall survival and disease-free survival.
By expanding the indication, a new active ingredient is now available that is subject to health insurance coverage and whose use in other areas has already been tried and tested for many years. It represents an alternative to the previously common chemical castration with other GnRH analogues such as goserelin. The clinical value in breast carcinoma remains to be seen; in any case, the options for eliminating ovarian function have become more diverse.
Source: “New: Pamorelin® LA 3.75 mg is approved and reimbursable for the treatment of breast cancer,” December 2020, Debiopharm International S.A.
Further reading:
- Francis PA, et al: Tailoring Adjuvant Endocrine Therapy for Premenopausal Breast Cancer. N Engl J Med. 2018; 379(2): 122-137.
- Pamorelin® LA Technical Information, as of August 2020, www.swissmedicinfo.ch.
InFo ONCOLOGY & HEMATOLOGY 2021; 9(1): 20
