Pemetrexed is a multi-targeted anti-folate, that is used for non-small cell lung cancer and mesothelioma. There are several clinical studies of pemetrexed in breast cancer, but these are largely done before the wide use of premedication (steroid and vitamin B12) for pemetrexed. Moreover, it has not been studied in combination with vinorelbine, which is a commonly used drug for anthracycline- and taxane-pretreated metastatic breast cancer.

This is a randomized phase II study of pemetrexed plus vinorelbine versus vinorelbine in patients with recurrent or metastatic breast cancer previously treated with or resistant to an anthracycline and taxane.

Inclusion Criteria:

1. histologically confirmed, recurrent or metastatic breast cancer
2. HER2-negative
3. ECOG PS 0-2
4. Age ≥ 20 years
5. Anthracycline- and Taxane-pretreated
6. Wash-out period of 3 weeks for cytotoxic chemotherapy
7. Wash-out period of 2 weeks for hormone therapy or radiotherapy
8. measurable or non-measurable lesions by RECIST v1.1
9. Adequate hematological functions : ANC ≥1,500/mm3, Platelet ≥100,000/mm3, Hb≥ 9g/dL
10. Adequate liver functions
11. Adequate renal functions : sCr≤1.5mg/dL
12. Subjects willing to follow study protocol
13. Informed consent before study entry

Exclusion Criteria:

1. More than 3 lines of chemotherapy for metastatic breast cancer
2. Pregnant or breastfeeding women
3. Previous exposure to Pemetrexed or Vinorelbine
4. Neuropathy (grade 2 or more)
5. Symptomatic CNS metastasis
6. History of malignant disease within 5 years (except for cured basal cell cancer or squamous cell cancer of skin, cured thyroid cancer, in-situ cervical cancer)
7. Hypersensitivity to study medication or related drugs
8. Concomitant vaccination for yellow fever