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

NCT07401381 | Not Yet Recruiting Phase 1 DMC FDA Drug

• 2 other identifiers: ROV-SIE-2025-012025-523269-31-00
• Study Type: interventional
• Target: 120
• Locations: 0 countries
• Sites: N/A

Brief Summary

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.

Conditions

Hormone Receptor Positive Early Breast Cancer

Keywords

Letrozole SIE; Early breast cancer; Pharmacokinetics; Bioavailability; Safety; Endocrine therapy; Injectable

Outcome Measures

Primary Outcomes (1)

• Area under the concentration-time curve within a dosing interval at Steady-State (SS AUCtau)

  Individual and mean area under the concentration-time curve within a dosing interval at steady-state

  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 Outcomes (14)

• Adverse Events

  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

  At pre-dose and 1 hour after each Letrozole SIE administration in TP2

• Injection-related pain score

  From baseline TP2 to the follow-up visit on Day 281

• Bone mineral density (BMD) by dual energy x-ray absorptiometry (DXA)

  From screening to Day 281 TP2

• Average plasma drug concentration during a dosing interval at Steady-State (SS Cave)

  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

Other Outcomes (2)

• Hormone supression

  From screening to the final follow-up visit on Day 281 (or Day 421 for the subset of participants in the Extension Period)

• CYP2A6 genotyping

  From screening to final follow-up visit Day 281 (or Day 421 for the subset of participants in the Extension Period)

Study Arms (2)

US-sourced oral Femara®

EXPERIMENTAL

Drug: US-sourced oral Femara® + Letrozole SIE

EU-sourced oral Femara®

EXPERIMENTAL

Drug: EU sourced oral Femara® + Letrozole SIE

Interventions

US-sourced oral Femara® + Letrozole SIE DRUG

US-sourced Femara® 2.5 mg/day oral for 14 days (treatment period 1) + quarterly injectable Letrozole SIE (treatment period 2)

US-sourced oral Femara®

EU sourced oral Femara® + Letrozole SIE DRUG

EU-sourced oral Femara® 2.5 mg/day for 14 days (treatment period 1) + quarterly injectable Letrozole SIE (treatment period 2)

EU-sourced oral Femara®

Eligibility Criteria

• Age: 18 Years - 80 Years
• Sex: female
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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.

You may not qualify if:

• 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.

Sponsors & Collaborators

• Rovi Pharmaceuticals Laboratories: lead

MeSH Terms

Conditions

Breast Neoplasms

Condition Hierarchy (Ancestors)

Neoplasms by Site; Neoplasms; Breast Diseases; Skin Diseases; Skin and Connective Tissue Diseases

Central Study Contacts

Clinical Operations. Laboratorios Farmacéuticos ROVI

CONTACT

+34913756230; departamento.medico@rovi.es

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: January 22, 2026
• First Posted: February 10, 2026
• Study Start: March 1, 2026
• Primary Completion (Estimated): May 1, 2028
• Study Completion (Estimated): October 1, 2028
• Last Updated: February 10, 2026

Record last verified: 2026-02