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: Seven of the 13 patients had exhibited a subclinical hypertensive state before cyclosporin A therapy .
### Output Text:
Seven of the 13 patients had exhibited a subclinical hypertensive state before <span class="chemical">cyclosporin A</span> therapy . 