A Study to Compare the Steady-State Bioavailability of Injectable Letrozole SIE and Oral Letrozole in Post-Menopausal Women With Hormone Receptor Positive Early Breast Cancer
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- The protocol lists: US-sourced oral Femara® + Letrozole SIE, EU sourced oral Femara® + Letrozole SIE.
- Who it may be relevant to
- Registry conditions: Hormone Receptor Positive Early Breast Cancer. Basic parameters: 18 years — 80 years · Female.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- Spain
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
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Official title
An Open-Label, One-Sequence Study to Evaluate the Steady-State Comparative Bioavailability of Quarterly Letrozole SIE and Once Daily 2.5 mg Oral Letrozole (Femara®) in Post-Menopausal Women Treated With Endocrine Therapy for Hormone Receptor-Positive Early Breast Cancer. (SIE-1)
Overview
The study aims to compare the amount of the drug letrozole that gets into the bloodstream after multiple doses of the quarterly injection Letrozole SIE, versus multiple doses of the standard oral daily tablet of letrozole (Femara®), in women who have gone through menopause and have received treatment for hormone receptor-positive early breast cancer. Participants must have completed at least five years of hormone therapy with at least two of those years with letrozole before starting their participation in the study. Women who have completed four years of hormone therapy are also eligible if their doctor considers them at low risk of cancer returning.
Detailed description
The primary objective of the study is to evaluate the steady-state comparative bioavailability of quarterly injectable Letrozole SIE compared to United States (US)-sourced oral Femara® in the US-sourced arm and of quarterly injectable Letrozole SIE compared to European Union (EU)-sourced oral Femara® in the EU-sourced arm, in post-menopausal women treated with endocrine therapy for hormone-receptor positive (HR+) early breast cancer (EBC). The study also aims to characterize the elimination phase of Letrozole SIE after multiple doses.
The study consists of four periods: Screening, Treatment Period 1 (TP1), Treatment Period 2 (TP2) and Extension Period. After the Screening Period, participants will be randomized to two different arms: US-sourced oral Femara® or EU-sourced oral Femara® for 14 days to achieve the steady-state concentrations of letrozole in TP1. After receiving the latest oral letrozole dose, participants from both arms will start TP2. In TP2, quarterly injectable Letrozole SIE will be administered to achieve steady-state. After TP2, a subset of participants (up to 60 participants, regardless of which study arm they belong to) will continue in the study for the assessment of the elimination phase of Letrozole SIE after multiple doses during the Extension Period.
It is estimated that approximately 120 subjects should be randomized.
Interventions
- Drug US-sourced oral Femara® + Letrozole SIE
US-sourced Femara® 2.5 mg/day oral for 14 days (treatment period 1) + quarterly injectable Letrozole SIE (treatment period 2) - Drug EU sourced oral Femara® + Letrozole SIE
EU-sourced oral Femara® 2.5 mg/day for 14 days (treatment period 1) + quarterly injectable Letrozole SIE (treatment period 2)
Primary outcome measures
- Area under the concentration-time curve within a dosing interval at Steady-State (SS AUCtau) [Time frame: After multiple doses of Letrozole SIE until Day 281 TP2 and after multiple doses of US-sourced oral Femara® or EU-sourced oral Femara® on Day 14 TP1]
Secondary outcome measures (12)
- Adverse Events [Time frame: From the time of obtaining signed informed consent until the final follow-up visit on Day 281 (or Day 421 for the subset of participants in the Extension Period)]
- Injection site reactions [Time frame: At pre-dose and 1 hour after each Letrozole SIE administration in TP2]
- Injection-related pain score [Time frame: From baseline TP2 to the follow-up visit on Day 281]
- Bone mineral density (BMD) by dual energy x-ray absorptiometry (DXA) [Time frame: From screening to Day 281 TP2]
- Average plasma drug concentration during a dosing interval at Steady-State (SS Cave) [Time frame: After multiple doses of Letrozole SIE until Day 281 TP2 and after multiple doses of US-sourced oral Femara® or EU-sourced oral Femara® at Day 14 TP1]
- Minimum drug concentration at steady-state (Cmin ss) [Time frame: After multiple doses of Letrozole SIE until Day 281 TP2 and after multiple doses of US-sourced oral Femara® or EU-sourced oral Femara® at Day 14 TP1]
- Maximum plasma concentration at steady-state (Cmax ss) [Time frame: After multiple doses of Letrozole SIE at Day 281 TP2 and after multiple doses of US-sourced oral Femara® or EU-sourced oral Femara® at Day 14 TP1]
- Letrozole blood level percent fluctuation [Time frame: After multiple doses of Letrozole SIE at Day 281 TP2 and after multiple doses of US-sourced oral Femara® or EU-sourced oral Femara® at Day 14 TP1]
- Time to peak observed concentration (Tmax) [Time frame: After multiple doses of Letrozole SIE until Day 281 TP2 and after multiple doses of US-sourced oral Femara® or EU-sourced oral Femara® at Day 14 TP1]
- Steady-State (SS) [Time frame: After multiple doses of Letrozole SIE until Day 281 TP2 and after multiple doses of US-sourced oral Femara® or EU-sourced oral Femara® at Day 14 TP1]
- Terminal rate constant (λz) [Time frame: After multiple doses of Letrozole SIE in TP2 until Day 421 in the Extension Period]
- Terminal half-life (t1/2) [Time frame: After multiple doses of Letrozole SIE in TP2 until Day 421 in the Extension Period]
Eligibility criteria
Inclusion criteria
- Women with weight of ≥50 kg and a Body Mass Index (BMI) ≥19 kg/m2 and ≤39 kg/m2
- Postmenopausal women.
- Women with confirmed diagnosis of HR+/HER2- or HR+/HER2+ early stage breast cancer who have completed at least 5 years of endocrine therapy, at least 2 years of which were with letrozole. Participants at a low risk of relapse, as assessed by the investigator, can also be eligible after completing 4 years of adjuvant endocrine therapy, at least 2 of which were with letrozole.
- Women in good health.
- Women who have undergone breast imaging per applicable guidelines (e.g., mammogram) within the last 12 months with no evidence of malignancy (documentation required), and if not done, must be willing to have 1 performed prior to baseline.
Exclusion criteria
- Presence of an uncontrolled, unstable, clinically significant medical condition.
- Have used estrogen or progesterone systemic or topical therapy, oral contraceptives, androgens, LH-releasing hormone analogs, prolactin inhibitors, or antiandrogens within 3 months prior to screening.
- Use of inducers or inhibitors of CYP3A4 and CYP2A6.
- Diagnosed with osteoporosis.
- Preexisting cardiovascular disease
- Positive result for hepatitis B surface antigen, hepatitis B core antibody, hepatitis C antibody, or HIV antibodies.
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: No
Study design
- Allocation
- Randomized
- Model
- Parallel assignment
- Masking
- Open label
- Primary purpose
- Treatment
Study locations
Spain · 1 center
- Hospital Clínico Universitario Virgen de la Arrixaca (Investigational Site number ESP-009) — Murcia
Identifiers
NCT: NCT07401381 · ROV-SIE-2025-01 · 2025-523269-31-00