Paricalcitol and Chemotherapy in Treating Women With Metastatic Breast Cancer

OBJECTIVES:

Primary

• To determine the ability to administer 8 continuous weeks of therapy within the first 3 months of enrollment with paricalcitol when given together with taxane or ixabepilone therapy in women with metastatic breast cancer.
• To estimate the proportion of patients who successfully complete 8 continuous weeks of therapy as well as the proportion of patients who achieve a 'steady-state' dose.

Secondary

• To determine a dose of paricalcitol that can be taken continuously that maintains a normal calcium level when combined with a taxane or ixabepilone.
• To determine if baseline levels of 25-hydroxycholecalciferol and parathyroid hormone (PTH) are associated with time to treatment failure in these patients.
• To determine if PTH levels decline from baseline in patients treated with paricalcitol in combination with taxane or ixabepilone therapy.

OUTLINE: Beginning on day 1, patients receive oral paricalcitol. The dose of paricalcitol is increased every 2 weeks until the serum calcium level is between 9 mg/dL and 11.4 mg/dL. Once this level is reached, the patient continues at that dose for the duration of the study. Patients also receive paclitaxel albumin-stabilized nanoparticle formulation, docetaxel, or paclitaxel once a week or once every 3 weeks or ixabepilone once every 3 weeks. Treatment continues for at least 12 weeks in the absence of disease progression or unacceptable toxicity.

Inclusion criteria

• Histologically confirmed invasive breast cancer

• Metastatic or recurrent disease
• Patients with bone metastasis only are eligible and evaluable for time to progression
• Candidate for taxane or ixabepilone therapy
• At least one lesion that can be measured in at least one diameter ≥ 2 cm by CT scan
• No symptomatic brain metastases or other symptomatic CNS metastases
• ECOG performance status 0 or 1
• Life expectancy > 3 months
• ANC ≥ 1,500/mm³
• Platelet count ≥ 100,000/mm³
• Hemoglobin ≥ 9 g/dL
• Serum creatinine ≤ 2.0 mg/dL
• Total bilirubin ≤ 2.0 g/dL
• Albumin corrected serum calcium < 10.5 mg/dL
• Fertile patients must use effective contraception during and for at least 1 year after study participation
• At least 2 weeks since prior chemotherapy or radiation therapy
• Prior and concurrent taxane or ixabepilone therapy allowed
• Concurrent oral multivitamins allowed (i.e., Centrum or One a Day)
• Concurrent bisphosphonates allowed

Exclusion criteria

• History of allergy to calcitriol, paricalcitol, or other Vitamin D compounds
• History of drug or alcohol abuse within the past 6 months
• History of other malignancy except inactive nonmelanoma skin cancer, adequately treated stage I or II cancer from which the patient is currently in complete remission, or other cancer if the patient has been disease-free for 5 or more years
• Serious medical illness that would limit survival to < 3 months
• Active, uncontrolled bacterial, viral or fungal infection
• Poorly controlled diabetes
• Concurrent supplemental calcium
• Concurrent digitalis compounds
• Concurrent chemotherapy
• Concurrent biologic therapy, including trastuzumab and bevacizumab
• Concurrent hormonal agents for breast cancer except luteinizing hormone-releasing hormone agonists