Megestrol Acetate for Fatigue Management in T-DXd Treated Breast Cancer

A Multicenter, Double-Blind, Placebo-Controlled, Phase III Clinical Trial Evaluating Megestrol Acetate for the Management of Fatigue in Advanced Breast Cancer Patients Treatment With Trastuzumab Deruxtecan

This study aims to evaluate whether the combination of Megestrol Acetate at the initiation of Trastuzumab Deruxtecan (T-DXd) treatment can effectively prevent and alleviate T-DXd-related fatigue, thereby improving the quality of life for advanced breast cancer patients.

Evaluate the efficacy and safety of Megestrol Acetate (MA) in improving fatigue in breast cancer patients after T-DXd treatment.

Inclusion Criteria:

1. Female, aged 18-75 years
2. Pathologically confirmed inoperable or metastatic breast cancer with complete ER, PR, and HER2 status
3. HER2-positive (IHC 3+ or IHC 2+ with FISH positive), HER2-low (IHC 1+ or IHC 2+ with FISH negative), or HER2-ultralow (IHC 0 with ≤10% weak incomplete membrane staining) [most recent specimen used]
4. Investigator-assessed indication for Trastuzumab Deruxtecan (T-DXd) therapy
5. No prior treatment with Trastuzumab Deruxtecan
6. Received ≤5 lines (including 5 lines) of prior chemotherapy
7. ECOG Performance Status 0-1
8. Estimated life expectancy ≥12 weeks
9. Adequate organ function
10. Reliable contraception or negative serum/urine pregnancy test within 7 days prior to enrollment; willing to use appropriate contraception during study and for 8 weeks after last dose
11. Voluntary participation with good compliance

Exclusion Criteria:

1. Severe underlying disease, comorbidities, active infection, or severe metabolic disorders
2. Clinically significant severe fatigue at baseline (FACIT-F score <30)
3. Currently receiving other antitumor therapies
4. Pregnant or lactating patients
5. Poor compliance or unable to complete normal follow-up
6. History of allergy to megestrol acetate or other components of the formulation
7. History of thromboembolism (use with caution)
8. Other malignancies diagnosed within 5 years, except: resected non-melanoma skin cancer, adequately treated cervical carcinoma in situ, locally radically treated prostate cancer, surgically radically treated ductal carcinoma in situ, or malignancies diagnosed >2 years ago with no current disease evidence and untreated for ≤2 years before randomization
9. Any condition judged by investigator that may affect study conduct or outcome assessment