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: A daily oral dose of 100 mg lamivudine for 2 weeks before transplantation for 10 patients enabled 57 . 1 % ( 4 / 7 ) and 62 . 5 % ( 5 / 8 ) of HBV - DNA and HBeAg positive patients respectively to convert to be negative .
### Output Text:
A daily oral dose of 100 mg <span class="chemical">lamivudine</span> for 2 weeks before transplantation for 10 patients enabled 57 . 1 % ( 4 / 7 ) and 62 . 5 % ( 5 / 8 ) of HBV - DNA and <span class="chemical">HBeAg</span> positive patients respectively to convert to be negative . 