The FDA approved trastuzumab-dttb, a biosimilar to trastuzumab, for three cancer indications.

Trastuzumab-dttb (Ontruzant, Samsung Biopesis), a HER2/NEU receptor antagonist, is indicated for adjuvant treatment of early breast cancer, metastatic breast cancer and metastatic gastric cancer.

Trastuzumab-dttb is the third biosimilar to trastuzumab (Herceptin, Genentech) to receive regulatory approval in the United States.

Biosimilars are biological products that have been shown to be highly similar to an already-approved biological product. The pre-approved agents are called reference products.

Biosimilars must have no clinically meaningful differences from their reference products with regard to effectiveness or safety. Only small differences in clinically inactive components are allowable with biosimilar products.