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: Evaluation of RAD001 plus standard therapy for metastatic NSCLC continues .
### Output Text:
Evaluation of <span class="chemical">RAD001</span> plus standard therapy for metastatic NSCLC continues . 