Terminated: Amgen decision following Primary Analysis. Not due to safety reason

This randomized phase 3 trial is studying the effect of denosumab to see if it can prevent disease recurrence in the bone or in any other part of the body, when it is given as adjuvant therapy for women with early-stage breast cancer, who are at high risk of disease recurrence.

Eligible participants were randomized in a 1:1 ratio to receive denosumab 120 mg or placebo subcutaneously (SC) for up to 5 years. Randomization was stratified based on:

1. Breast cancer therapy/lymph node (LN) status: neoadjuvant therapy/any LN status versus adjuvant therapy/LN negative (based on axillary LN dissection, or based on sentinel node status) versus adjuvant therapy/LN positive
2. Hormone receptor (estrogen receptor [ER]/progesterone receptor [PR]) status: ER and/or PR positive versus ER and PR negative
3. Human epidermal growth factor receptor 2 (HER-2) status: HER-2 positive versus HER-2 negative
4. Age: < 50 years versus ≥ 50 years
5. Geographic Region: Japan versus Other regions.

The primary analysis was conducted after all enrolled participants had the opportunity to complete 5 years of treatment from study day 1.

Inclusion Criteria:

• Histologically confirmed, American Joint Committee on Cancer (AJCC) stage II or III breast cancer

• High risk of breast cancer recurrence, defined as documented evidence of one or more of the following criteria:

  i) Biopsy evidence of breast cancer in regional lymph node(s) (LN) (node-positive disease); Nodal micrometastases only are not considered node positive ii) Tumor size > 5 cm (T3) or locally advanced disease (T4)

• Documented pathological evaluation of the breast cancer for hormone receptor (estrogen receptor [ER] and progesterone receptor [PR]) status and HER-2 status

• Subjects must be receiving or be scheduled to receive standard of care systemic adjuvant or neoadjuvant chemotherapy and/or endocrine therapy and/or HER-2 targeted therapy

• For subjects receiving adjuvant therapy only:

• subjects must have undergone complete resection of the primary tumor with clean surgical margins, or subjects must have undergone resection of the primary tumor and be scheduled for further treatment of the primary tumor with curative intent. Definitive treatment must be planned to be completed within approximately 9 months of randomization

• Time between definitive surgery and randomization must be ≤ 12 weeks. Definitive surgery may include secondary interventions (e.g. to clear inadequate surgical margins)

• Subjects with node positive disease must have undergone treatment of axillary LN with curative intent, or subjects must be scheduled for further treatment of regional lymph nodes with curative intent. Definitive treatment must be planned to be completed within approximately 9 months of randomization

• Subjects must not have received prior neoadjuvant treatment. Endocrine treatment for less than 30 days prior to surgery is not considered prior neoadjuvant treatment

• For subjects receiving neoadjuvant therapy only:

• Time between start of neoadjuvant treatment and randomization must be ≤ 8 weeks and subjects must be scheduled to undergo definitive treatment (including surgery and/or radiotherapy) with curative intent within approximately 9 months of starting neoadjuvant treatment

• Female subjects with age ≥ 18 years

• Subjects with reproductive potential must have a negative pregnancy test within 14 days before randomization

• Serum calcium or albumin-adjusted serum calcium ≥ 2.0 mmol/L (8.0 mg/dL) and ≤ 2.9 mmol/L (11.5 mg/dL)

• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1

• Written informed consent before any study-specific procedure is performed

Exclusion Criteria:

• Prior or current evidence of any metastatic involvement of any distant site
• History of breast cancer (other than ductal carcinoma in situ [DCIS] or lobular carcinoma in situ [LCIS]) prior to the current diagnosis
• Osteoporosis requiring treatment at the time of randomization or treatment considered likely to become necessary within the subsequent six months
• Any prior or synchronous malignancy (other than breast cancer), except i) Malignancy treated with curative intent and with no evidence of disease for ≥ 5 years prior to enrollment and considered to be at low risk for recurrence by the treating physician ii) Adequately treated non-melanoma skin cancer or lentigo maligna without evidence of disease
• Active infection with Hepatitis B virus or Hepatitis C virus
• Known infection with human immunodeficiency virus (HIV)
• Prior history or current evidence of osteomyelitis/osteonecrosis of the jaw
• Active dental or jaw condition which requires oral surgery
• Planned invasive dental procedure for the course of the study
• Non-healed dental or oral surgery
• Use of oral bisphosphonates within the past 1 year
• Prior or current IV bisphosphonate administration
• Prior administration of denosumab
• Subject currently is enrolled in or has not yet completed at least 30 days since ending other investigational device or investigational drug study(s), or subject is receiving other investigational agent(s)
• Subject is pregnant or breast feeding, or planning to become pregnant within 7 months after the end of treatment.
• Subject is of child bearing potential and is not willing to use, in combination with her partner, 2 highly effective methods of contraception or abstinence during treatment and for 5 months after the end of treatment
• Subject has known sensitivity to any of the products to be administered during the study (e.g., mammalian derived products, calcium, or vitamin D)
• Subject has any kind of disorder that compromises the ability of the subject to give written informed consent and/or to comply with study procedures.
• Any major medical or psychiatric disorder that in the opinion of the investigator prevent the subject from completing the study or interfere with the interpretation of the study results