Treatment patterns of goserelin 3.6 mg once monthly and 10.8 mg every three months in women with breast cancer: A real-world analysis.
Authors: McCann Kelly Elizabeth , Kaklamani Virginia G. , Osman Noran , Cannon Joan , Brent Lonnie , Lucia Rachel , Li Chong , Duran Nicole , Gupta Sidharth , Martin Nancy Elizabeth 
Published: September 2024

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Background:
Goserelin is a gonadotropin-releasing hormone agonist used for ovarian function suppression in the treatment of pre- and peri-menopausal patients with breast cancer. Goserelin, administered as a subcutaneous implant, is available in doses of 3.6 mg once monthly or 10.8 mg every three months; goserelin 3.6 mg is approved in the US, and both the 3.6 mg and 10.8 mg doses are approved by Health Canada and the European Medicines Agency. A study utilizing US real-world evidence was conducted to characterize treatment patterns of patients treated with goserelin 3.6 mg and/or 10.8 mg.
Methods:
Electronic health record data of adult patients with a history of breast cancer and with ≥2 prescriptions of goserelin between 1 January 2017 – 31 December 2022 were identified through TriNetX. Index date was the initiation of goserelin administration. Patients were followed until 15 March 2024. Patient demographics, treatment adherence, and healthcare resource utilization (HCRU) were examined and summarized using descriptive analytics.
Results:
Overall, 3,620 patients were identified: 2,870 treated with goserelin 3.6 mg, 410 with goserelin 10.8 mg, and 340 who switched from goserelin 3.6 mg to 10.8 mg. Peak utilization of goserelin 10.8 mg (36.6%) and peak dosage switching (26.5%) occurred in 2020. Across groups, mean age at index date was 42.2–44.4 years, and patients were white (64.1–67.6%), black (11.8%–13.9%), Asian (8.0%–11.8%), and American Indian and/or Alaskan native (0.3%–2.9%). Of patients with known BMI, BMI mostly ranged between 18.5–24.9 kg/m
2
in all groups. Patients who switched from goserelin 3.6 mg to 10.8 mg had the longest median treatment duration (776 days) (Table). Patients treated with goserelin 10.8 mg remained on treatment for a median of 426 days; 74.4% of these patients were treatment-adherent (Table). In comparison, patients treated with goserelin 3.6 mg had a shorter median treatment duration (226 days) and were less adherent (56.4%) (Table). HCRU during the 12 months after index date was broadly similar across groups.
Conclusions:
Treatment with goserelin 10.8 mg every three months is associated with greater adherence and longer treatment duration, compared with 3.6 mg once monthly, in patients with a history of breast cancer. Patients who switched from goserelin 3.6 mg to 10.8 mg were treatment-adherent for nearly two years, consistent with clinical recommendations.

Goserelin 3.6 mg (n = 2,870)
Goserelin 10.8 mg (n = 410)
Switched from goserelin 3.6 mg to 10.8 mg (n = 340)

Median duration of treatment (days)
264
429
776

Median time to switch (days)
—
—
218

Patients adherent* to dosing schedule
1,608 (56.4%)
306 (74.4%)
—

Status as of March 15, 2024

Discontinued goserelin

2,018 (70.8%)
261 (64.3%)
173 (50.9%)

Death

88 (3.1%)
10 (2.5%)
3 (0.9%)

*Defined as: ≤36 days between prescriptions (3.6 mg) or ≤108 days between prescriptions (10.8 mg).