January 18, 2019
The FDA has approved trastuzumab-dttb (Ontruzant; Merck), as a biosimilar to trastuzumab (Herceptin; Genentech) for the treatment of certain patients with HER2-overexpressing breast cancer or metastatic gastric or gastroesophageal junction adenocarcinoma, according to an e-mail–based statement from the administration.
Specifically, trastuzumab-dttb is indicated for the adjuvant treatment of HER2-overexpressing, node-positive or node negative breast cancer in combination with doxorubicin, cyclophosphamide, and paclitaxel or docetaxel; in combination with docetaxel and carboplatin; or as a single agent multi-modality anthracycline based therapy. The drug is also approved in combination with paclitaxel for the first-line treatment of HER2-overexpressing metastatic breast cancer or as a single agent for the treatment of HER2-overexpressing metastatic breast cancer in patients who have received ≥1 chemotherapy regimen, and in combination with cisplatin and capecitabine or 5-fluorouracil for the treatment of patients with HER2-overexpressing metastatic gastric or gastroesophageal junction adenocarcinoma.
This approval was based on a comprehensive review of animal, human pharmacokinetic, clinical immunogenicity, and other data demonstrating that trastuzumab-dttb is a biosimilar to the reference drug.
Common adverse reactions observed with trastuzumab-dttb include in patients with adjuvant breast cancer include headache, diarrhea, nausea, and chills. Among patients with metastatic breast cancer, common adverse reactions include fever, child, headache, infection, congestive heart failure, insomnia, cough, and rash. For those with metastatic gastric cancer, the most common adverse reactions are neutropenia, diarrhea, fatigue, anemia, stomatitis, weight loss, upper respiratory tract infections, fever, thrombocytopenia, mucosal inflammation, nasopharyngitis, and dysgeusia.