In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: METHODS : A Phase II study of the combination of cisplatin plus amifostine was conducted in patients with progressive metastatic breast carcinoma who had received one , but not more than one , chemotherapy regimen for metastatic disease .
### Output Text:
METHODS : A Phase II study of the combination of <span class="chemical">cisplatin</span> plus <span class="chemical">amifostine</span> was conducted in patients with progressive metastatic breast carcinoma who had received one , but not more than one , chemotherapy regimen for metastatic disease . 