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 : Stage IIIb or IV NSCLC patients , with two or fewer prior chemotherapy regimens , one platinum based ( stratum 1 ) or both chemotherapy and epidermal growth factor receptor tyrosine kinase inhibitors ( stratum 2 ) , received RAD001 10 mg / day until progression or unacceptable toxicity .
### Output Text:
METHODS : Stage IIIb or IV NSCLC patients , with two or fewer prior chemotherapy regimens , one <span class="chemical">platinum</span> based ( stratum 1 ) or both chemotherapy and epidermal growth factor receptor <span class="chemical">tyrosine</span> kinase inhibitors ( stratum 2 ) , received <span class="chemical">RAD001</span> 10 mg / day until progression or unacceptable toxicity . 