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# FDA Approves Merck’s Herceptin Biosimilar
- URL: https://www.fdaweb.com/fda-approves-mercks-herceptin-biosimilar/
- Published: 2019-01-18T12:00:00.000Z
- Updated: 2026-09-15T00:55:26.000Z
- Author: David McFarland
- Tags: Biologics, #legacy-id-D5143185

FDA has approved Merck’s Ontruzant (trastuzumab-dttb) as a biosimilar to Genentech’s Herceptin (transtuzumab) for patients with HER2-overexpressing breast cancer. The product will be manufactured by Samsung Bioepis. The Ontruzant [prescribing information](https://www.accessdata.fda.gov/drugsatfda%5Fdocs/label/2019/761100s000lbl.pdf?utm%5Fcampaign=FDA%20approves%20Ontruzant%20%28trastuzumab-dttb%29%2C%203rd%20biosimilar%20to%20Herceptin%20%28trastuzumab%29&utm%5Fmedium=email&utm%5Fsource=Eloqua) says common expected side effects include headache, diarrhea, nausea, chills, fever, infection, congestive heart failure, insomnia, cough, and rash. Serious expected side effects include worsening of chemotherapy-induced neutropenia. Like Herceptin, the labeling contains a Boxed Warning for increased risks of cardiomyopathy, infusion reactions, pulmonary toxicity, and embryo-fetal toxicity.