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: Eighty - seven percent of the patients had received immunomodulatory drugs included in some line of therapy before bort - dex .
### Output Text:
Eighty - seven percent of the patients had received immunomodulatory drugs included in some line of therapy before <span class="chemical">bort</span> - <span class="chemical">dex</span> . 