Breast CancerPhase 2IFOCOSNCT07610733
Impact of Formulation Change on Ovarian Suppression in Young Breast Cancer Patients.
A Phase 2 study testing 1-month GnRH and 3-month GnRH in people with Breast Cancer, run by Fudan University.
Trial summary
This is a multicenter, prospective, randomized controlled, phase II study. The primary objective is to evaluate the effect of endocrine therapy modification (switching from a 3-month to a 1-month GnRHa) versus continuation of the 3-month GnRHa on E2 control at 3 months in young patients with hormone receptor-positive… Read more about this study
- Who is it for?
- Ages 18 to 45 years, women only
- Conditions the study is for
- Breast Cancer
- What is being tested?
- 1-month GnRH and 3-month GnRH
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 100 participants
- Where
- No sites listed yet
- Study dates
- 1 Jun 2026to 1 Jun 2030
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 45 years
- Women only
- No healthy volunteers
- Adult
Who may be able to join
- Step 1：iOFS detection phase
- Female, aged ≥18 and ≤45 years;
- Histologically confirmed hormone receptor-positive (HR+) (estrogen receptor [ER] and/or progesterone receptor [PR] ≥1%) and human epidermal growth factor receptor 2-negative (HER2-) early invasive breast cancer (stage I-III according to the American Joint Committee on Cancer [AJCC], version 8)；
- Completed curative surgery, with prior (neo)adjuvant chemotherapy and radiotherapy completed if applicable;
- Currently receiving adjuvant therapy with a 3-month GnRH agonist (GnRHa) plus aromatase inhibitor (AI) or tamoxifen (TAM), with or without CDK4/6 inhibitors (excluding abemaciclib due to its potential interference with estradiol monitoring), for ≥1 dose, and presenting with estradiol (E2) ≥30 pg/mL within 28 days prior to enrollment (measured by CLIA).
- Eastern Cooperative Oncology Group (ECOG) performance status score of 0-1; adequate bone marrow, hepatic, renal, and cardiac function.
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- Voluntarily sign a written informed consent form before the trial screening.
- Step 2：Randomized treatment phase
- iOFS confirmed using the SEMS assay (E2 ≥30 pg/mL);
- Ongoing adjuvant therapy with a 3-month GnRHa plus AI or TAM, with or without CDK4/6 inhibitors.
- No evidence of disease progression.
Who cannot join
- Step 1：iOFS detection phase
- Bilateral breast cancer, inflammatory breast cancer, or distant metastasis;
- Use of GnRHa for ovarian function preservation;
- History of ovarian resection or ablation; planned pregnancy or breastfeeding;
- Concomitant use of hormonal agents other than estrogen, progesterone, selective estrogen receptor modulators (SERM), or selective estrogen receptor degraders (SERD);
- Severe uncontrolled comorbidities;
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- Other malignancies within the past 5 years (except for curatively treated carcinoma in situ of the cervix or basal cell carcinoma);
- Failure to comply with follow-up or psychiatric disorders.
- Step 2：Randomized treatment phase
- a)Prior conversion from a 3-month GnRHa to a 1-month GnRHa.
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
Official title: A Multicenter, Prospective, Randomized Controlled Study-Impact of Formulation Change on Ovarian Suppression in Young Breast Cancer Patients (IFOCOS)
This is a multicenter, prospective, randomized controlled, phase II study. The primary objective is to evaluate the effect of endocrine therapy modification (switching from a 3-month to a 1-month GnRHa) versus continuation of the 3-month GnRHa on E2 control at 3 months in young patients with hormone receptor-positive breast cancer and iOFS.
Read the detailed description
In China, breast cancer occurs at a young age, with a peak incidence at 40-49 years; patients aged ≤45 years account for 20%-24% of cases, and this proportion is increasing. Ovarian function suppression (OFS) combined with aromatase inhibitor (AI) or tamoxifen (TAM), with or without CDK4/6 inhibitors, has become a preferred adjuvant endocrine therapy for intermediate to high-risk premenopausal hormone receptor-positive (HR+) patients with HR+ breast cancer. AI is effective in premenopausal women only when ovarian estrogen production is suppressed, which can be achieved with GnRH agonists (GnRHa). The 3-month GnRHa formulation is commonly preferred in the real world due to its convenience and reduced injection frequency; however, its effectiveness compared with the 1-month formulation remains a concern.
Among premenopausal patients receiving GnRHa combined with AI or TAM, approximately 8% experience incomplete ovarian function suppression (iOFS, E2 ≥30 pg/mL). Persistent iOFS may reduce the efficacy of endocrine therapy and potentially increase the risk of disease recurrence. Current clinical guidelines recommend monitoring serum estradiol (E2) levels during GnRHa treatment and suggest potential management strategies, including switching GnRHa formulations from 3-month to 1-month or modifying endocrine therapy (e.g., AI to TAM). However, evidence supporting these strategies is largely derived from retrospective studies or small case series, and prospective data remain limited. This multicenter, prospective, randomized, phase II study is designed to evaluate whether switching from a 3-month to a 1-month GnRHa can reduce E2 levels to <30 pg/mL within 3 months in premenopausal HR+ young breast cancer patients with iOFS. This study will also assess the long-term efficacy and safety of this strategy.
- Conditions
- Breast Cancer
- Being tested
- 1-month GnRH, 3-month GnRH
- Keywords
- Breast Cancer, ovarian suppression
- Medical subject headings
- Breast Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
1-month GnRHDrug
1-month GnRH (goserelin 3.6 mg depot or goserelin 3.6 mg implant or leuprolide 3.75 mg depot) +endocrine therapy (aromatase inhibitor/tamoxifen±CDK4/6 inhibition)
3-month GnRHDrug
3-month GnRH (goserelin 10.8 mg implant or leuprolide 11.25 mg depot) + endocrine therapy (aromatase inhibitor/tamoxifen±CDK4/6 inhibition)
| Study group | Role | What they receive |
|---|---|---|
| Experimental: 1-month GnRH + endocrine therapy | Experimental | 1-month GnRH (goserelin 3.6 mg depot or goserelin 3.6 mg implant or leuprolide 3.75 mg depot) +endocrine therapy (aromatase inhibitor/tamoxifen±CDK4/6 inhibition) Receives: Drug: 1-month GnRH |
| Active Comparator: Control | Active comparator | 3-month GnRH (goserelin 10.8 mg implant or leuprolide 11.25 mg depot) + endocrine therapy (aromatase inhibitor/tamoxifen±CDK4/6 inhibition) Receives: Drug: 3-month GnRH |
What is being measured
The primary outcome is the main question the study is designed to answer.
Proportion of Participants with E2 <30 pg/mL at 3 Months
The primary endpoint is defined as the proportion of patients with E2 <30 pg/mL at 3 months, comparing patients who switch to GnRHa 1M versus those who continue GnRHa 3M therapy.
Measured: 3 months post randomization
Secondary outcomes (7)
Proportion of patients with E2 <30 pg/mL at 6 months after randomization
This endpoint is defined as the proportion of patients with E2 <30 pg/mL at 6 months, comparing patients who switch to GnRHa 1M versus those who continue GnRHa 3M therapy.
Measured: 6 months post randomization
Time to adequate ovarian function suppression
This endpoint is defined as the time from the first occurrence of iOFS to the first measurement of E2 <30 pg/mL.
Measured: Assessed over a period of up to 12 months following randomization
Patient Age
Age of participants at the time of randomization, categorized by iOFS status (Persistent vs. Transient).
Measured: At randomization
3-year invasive disease-free survival in patients who switch to GnRHa 1M versus those who continue GnRHa 3M therapy
Invasive disease-free survival is defined as the time from randomization to the first occurrence of locoregional recurrence, distant metastasis, second primary breast cancer, or death from any cause.
Measured: From the date of randomization until the date of locoregional recurrence, distant metastasis, second primary breast cancer, or death from any cause, up to 3 months
3-year invasive disease-free survival in patients with persistent iOFS and those with transient iOFS
Measured: From the date of randomization until the date of locoregional recurrence, distant metastasis, second primary breast cancer, or death from any cause, up to 3 months
Intraclass Correlation Coefficient (ICC) for the Consistency of the SEMS Method
The consistency of the SEMS method will be assessed by calculating the Intraclass Correlation Coefficient (ICC) between GnRHa 1M and GnRHa 1M at the post-assay time point.
Measured: post SEMS assay
Adverse events
Adverse events will be graded according to the NCI-CTCAE Version 5.0.
Measured: From the date of treatment initiation until the date of disease progression, intolerable toxicities, death, withdrawal of consent, or completion of planned 3-year postoperative follow-up, whichever occurred first
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 May 2026
- Study start1 Jun 2026 (estimated)
- Primary completion1 Sep 2027 (estimated)
- Study completion1 Jun 2030 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Breast CancerStudies of the same condition, open and under way.
- More trials run by Fudan UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Participants will be randomized into one of two groups: an intervention group that receives the 1-month GnRHa and a control group that receives the 3-month GnRHa.
- Masking
- None (open label)
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Fudan University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Jian Zhang,MD, Fudan University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07610733
- Sponsor's protocol ID
- IFOCOS
- Acronym
- IFOCOS
- Status last verified
- May 2026
- First submitted
- 14 May 2026
- Last updated
- 28 May 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 28 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Multicenter, Prospective, Randomized Controlled Study-Impact of Formulation Change on Ovarian Suppression in Young Breast Cancer Patients (IFOCOS)
- ClinicalTrials.gov ID
- NCT07610733
- Acronym / sponsor ID
- IFOCOS / IFOCOS
- Conditions
- Breast Cancer
- Keywords
- Breast Cancer, ovarian suppression
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 100 participants (estimated)
- Lead sponsor
- Fudan UniversityUniversity, hospital or other
- Study start
- 1 Jun 2026 (estimated)
- Primary completion
- 1 Sep 2027 (estimated)
- Study completion
- 1 Jun 2030 (estimated)
- First posted
- 28 May 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This is a multicenter, prospective, randomized controlled, phase II study. The primary objective is to evaluate the effect of endocrine therapy modification (switching from a 3-month to a 1-month GnRHa) versus continuation of the 3-month GnRHa on E2 control at 3 months in young patients with hormone receptor-positive breast cancer and iOFS.
Detailed description
In China, breast cancer occurs at a young age, with a peak incidence at 40-49 years; patients aged ≤45 years account for 20%-24% of cases, and this proportion is increasing. Ovarian function suppression (OFS) combined with aromatase inhibitor (AI) or tamoxifen (TAM), with or without CDK4/6 inhibitors, has become a preferred adjuvant endocrine therapy for intermediate to high-risk premenopausal hormone receptor-positive (HR+) patients with HR+ breast cancer. AI is effective in premenopausal women only when ovarian estrogen production is suppressed, which can be achieved with GnRH agonists (GnRHa). The 3-month GnRHa formulation is commonly preferred in the real world due to its convenience and reduced injection frequency; however, its effectiveness compared with the 1-month formulation remains a concern.
Among premenopausal patients receiving GnRHa combined with AI or TAM, approximately 8% experience incomplete ovarian function suppression (iOFS, E2 ≥30 pg/mL). Persistent iOFS may reduce the efficacy of endocrine therapy and potentially increase the risk of disease recurrence. Current clinical guidelines recommend monitoring serum estradiol (E2) levels during GnRHa treatment and suggest potential management strategies, including switching GnRHa formulations from 3-month to 1-month or modifying endocrine therapy (e.g., AI to TAM). However, evidence supporting these strategies is largely derived from retrospective studies or small case series, and prospective data remain limited. This multicenter, prospective, randomized, phase II study is designed to evaluate whether switching from a 3-month to a 1-month GnRHa can reduce E2 levels to <30 pg/mL within 3 months in premenopausal HR+ young breast cancer patients with iOFS. This study will also assess the long-term efficacy and safety of this strategy.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- Participants will be randomized into one of two groups: an intervention group that receives the 1-month GnRHa and a control group that receives the 3-month GnRHa.
| Arm | Type | Receives |
|---|---|---|
| Experimental: 1-month GnRH + endocrine therapy | Experimental | Drug: 1-month GnRH1-month GnRH (goserelin 3.6 mg depot or goserelin 3.6 mg implant or leuprolide 3.75 mg depot) +endocrine therapy (aromatase inhibitor/tamoxifen±CDK4/6 inhibition) |
| Active Comparator: Control | Active comparator | Drug: 3-month GnRH3-month GnRH (goserelin 10.8 mg implant or leuprolide 11.25 mg depot) + endocrine therapy (aromatase inhibitor/tamoxifen±CDK4/6 inhibition) |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (11 listed)
- Step 1：iOFS detection phase
- Female, aged ≥18 and ≤45 years;
- Histologically confirmed hormone receptor-positive (HR+) (estrogen receptor [ER] and/or progesterone receptor [PR] ≥1%) and human epidermal growth factor receptor 2-negative (HER2-) early invasive breast cancer (stage I-III according to the American Joint Committee on Cancer [AJCC], version 8)；
- Completed curative surgery, with prior (neo)adjuvant chemotherapy and radiotherapy completed if applicable;
- Currently receiving adjuvant therapy with a 3-month GnRH agonist (GnRHa) plus aromatase inhibitor (AI) or tamoxifen (TAM), with or without CDK4/6 inhibitors (excluding abemaciclib due to its potential interference with estradiol monitoring), for ≥1 dose, and presenting with estradiol (E2) ≥30 pg/mL within 28 days prior to enrollment (measured by CLIA).
Key exclusion criteria (10 listed)
- Step 1：iOFS detection phase
- Bilateral breast cancer, inflammatory breast cancer, or distant metastasis;
- Use of GnRHa for ovarian function preservation;
- History of ovarian resection or ablation; planned pregnancy or breastfeeding;
- Concomitant use of hormonal agents other than estrogen, progesterone, selective estrogen receptor modulators (SERM), or selective estrogen receptor degraders (SERD);
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| 1-month GnRH1-month GnRH (goserelin 3.6 mg depot or goserelin 3.6 mg implant or leuprolide 3.75 mg depot) +endocrine therapy (aromatase inhibitor/tamoxifen±CDK4/6 inhibition) | Drug | Experimental: 1-month GnRH + endocrine therapy |
| 3-month GnRH3-month GnRH (goserelin 10.8 mg implant or leuprolide 11.25 mg depot) + endocrine therapy (aromatase inhibitor/tamoxifen±CDK4/6 inhibition) | Drug | Active Comparator: Control |
Primary outcome
Proportion of Participants with E2 <30 pg/mL at 3 Months
Time frame: 3 months post randomization
The primary endpoint is defined as the proportion of patients with E2 <30 pg/mL at 3 months, comparing patients who switch to GnRHa 1M versus those who continue GnRHa 3M therapy.
7 secondary outcomes
Proportion of patients with E2 <30 pg/mL at 6 months after randomization
Time frame: 6 months post randomization
Time to adequate ovarian function suppression
Time frame: Assessed over a period of up to 12 months following randomization
Patient Age
Time frame: At randomization
3-year invasive disease-free survival in patients who switch to GnRHa 1M versus those who continue GnRHa 3M therapy
Time frame: From the date of randomization until the date of locoregional recurrence, distant metastasis, second primary breast cancer, or death from any cause, up to 3 months
3-year invasive disease-free survival in patients with persistent iOFS and those with transient iOFS
Time frame: From the date of randomization until the date of locoregional recurrence, distant metastasis, second primary breast cancer, or death from any cause, up to 3 months
Intraclass Correlation Coefficient (ICC) for the Consistency of the SEMS Method
Time frame: post SEMS assay
Adverse events
Time frame: From the date of treatment initiation until the date of disease progression, intolerable toxicities, death, withdrawal of consent, or completion of planned 3-year postoperative follow-up, whichever occurred first
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 28 May 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing 1-month GnRH and 3-month GnRH in people with Breast Cancer, run by Fudan University.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 11 inclusion and 10 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 28 May 2026. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Jian Zhang (+8664175590 ext. 85000, syner2000@163.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Proportion of Participants with E2 <30 pg/mL at 3 Months (time frame: 3 months post randomization). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 28 May 2026.