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: CONCLUSION : Although our findings support the observation that dexrazoxane reduces neither hematologic activity nor antitumor activity from doxorubicin clinically , the potent antagonism of daunorubicin activity raises concern ; a possible interference with anticancer efficacy certainly would call for renewed attention .
### Output Text:
CONCLUSION : Although our findings support the observation that <span class="chemical">dexrazoxane</span> reduces neither hematologic activity nor antitumor activity from <span class="chemical">doxorubicin</span> clinically , the potent antagonism of <span class="chemical">daunorubicin</span> activity raises concern ; a possible interference with anticancer efficacy certainly would call for renewed attention . 