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: PATIENTS AND METHODS : Two hundred ninety - seven patients with MBC and no prior chemotherapy for metastatic disease were randomized to receive either 60 mg / m ( 2 ) of Myocet ( M ) or conventional doxorubicin ( A ) , in combination with 600 mg / m ( 2 ) of cyclophosphamide ( C ) , every 3 weeks until disease progression or unacceptable toxicity .
### Output Text:
PATIENTS AND METHODS : Two hundred ninety - seven patients with MBC and no prior chemotherapy for metastatic disease were randomized to receive either 60 mg / m ( 2 ) of <span class="chemical">Myocet</span> ( M ) or conventional <span class="chemical">doxorubicin</span> ( A ) , in combination with 600 mg / m ( 2 ) of <span class="chemical">cyclophosphamide</span> ( C ) , every 3 weeks until disease progression or unacceptable toxicity . 