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: Haematological toxicity was greater for the combination than AraG alone , although median time to neutrophil and platelet recovery was consistent with other salvage therapies .
### Output Text:
Haematological toxicity was greater for the combination than <span class="chemical">AraG</span> alone , although median time to neutrophil and platelet recovery was consistent with other salvage therapies . 