• To compare the effects of L-carnitine therapy versus placebo on: other potential markers of anthracycline induced cardiotoxicity such as LV volume, LV systolic and diastolic function, troponin T (TnT) and NT-pro-brain natriuretic peptide (BNP)
• "Anthracycline-induced cardiotoxicity" and clinical cardiac outcomes
• Serum L-carnitine levels
• To assess: the safety of L-carnitine
• the predictive value of serum biomarkers (TnT, BNP, and L-carnitine levels) for cardiotoxicity and cardiac outcome (ejection fraction, LV volumes, congestive heart failure, and cardiac death)
• the effect of anthracyclines on plasma L-carnitine levels
• the correlation of L-carnitine levels with serum TnT and BNP levels

• A) Effect of L-carnitine versus placebo on:
• 1) LV end-systolic and end-diastolic volumes (RNA)
• 2) LV diastolic dysfunction (ECHO)
• 3) serum TnT and BNP measured with each cycle of chemotherapy (immediately prior to and 3 days after chemotherapy)
• 4) composite outcome of: cardiac death, clinical congestive heart failure, reduction in EF requiring termination of anthracycline therapy (LVEF reduction ≥ 10% and LVEF < 50%), dexrazoxane use or “anthracycline-induced cardiotoxicity”.
• 5) adverse events (e.g. chemotherapy efficacy, seizures, nausea, diarrhea).
• B)
• 6) correlation of serum biomarkers (serum L-Carnitine levels, serum TnT, BNP) with surrogate markers of cardiotoxicity (LV ejection fraction, LV volumes and diastolic dysfunction) will be performed.

Breast cancer is very common and afflicts 1 in 9 North American women. The treatment of breast cancer often requires the use of chemotherapy including "anthracyclines". Anthracyclines can damage the heart resulting in heart failure and even death. Clinicians and researchers are continually seeking methods that will reduce the toxic effects of anthracycline treatment.

L-carnitine is a substance that is produced naturally in the body and is required for normal heart function. Animal studies have suggested that L-carnitine protects the heart from the effects of anthracyclines, however this has not been verified in humans.

This study will assess the potential role of L-carnitine in the prevention of anthracycline induced heart damage. The investigators will enroll 144 patients into this study. Patients will be randomly assigned to L-carnitine therapy or to standard care (no L-carnitine therapy). Patients in the L-carnitine group will receive oral and intravenous L-carnitine prior to and after their anthracycline therapy. Patients will undergo regular follow up and testing to assess heart function. The investigators believe that patients treated with L-carnitine will benefit and have fewer complications associated with anthracycline treatment.

Inclusion Criteria:

• Female patients must have histologically or cytologically indicated breast cancer (stages I, II, III) eligible for adjuvant anthracycline chemotherapy [FEC100 or AC-Taxol(paclitaxel) every 21 days.
• HER2 negative or HER2 positive breast cancer by immunohistochemistry (IHC3+) and/or fluorescent in-situ hybridization.
• Eastern cooperative oncology group (ECOG) performance status = 0, 1, 2
• Age ≥ 18 years old.
• Ability to understand and the willingness to sign a written informed consent document.
• The effects of L-carnitine on the developing human fetus at the recommended therapeutic dose are unknown. For this reason, women of child-bearing potential must agree to use adequate contraception prior to study entry and for the duration of study participation. Should a woman become pregnant or suspect she is pregnant while participating in this study, she should inform her treating physician immediately.

Exclusion Criteria:

• Patients with evidence of metastatic breast cancer.
• Resting LV ejection fraction < 50%.
• Patients having received previous anthracycline therapy or contraindication to anthracycline.
• Patients having a contraindication to L-carnitine therapy
• Dexrazoxane therapy at the time of enrollment.

• Patients with abnormal baseline bloodwork:

  • hemoglobin ≤ 100 mg/L
  • platelets ≤ 100 x 10^9/L
  • white blood cells ≤ 4 x 10^9/L
  • creatinine, AST, ALT, bilirubin > 1.5 x the upper normal limits
• Participation in another randomized clinical trial.
• Patients having significant cardiac disease (previous myocardial infarction, congestive heart failure, or hemodynamically significant valvular heart disease) that would limit compliance with study requirements.
• Patients taking medication that may affect LV function (b-blockers, amiodarone, ACE-inhibitors, calcium channel blockers, or digoxin).
• Patients with symptoms of heart failure.
• Patients unable to participate in a study requiring long term follow up.
• Pregnant or lactating women.