In the Clinic provides overviews of novel oncology agents, addressing indications, mechanisms of action, administration recommendations, safety profiles, and other essential information needed for the appropriate clinical use of these drugs.

On December 1, 2017, trastuzumab-dkst (Ogivri) was approved as a biosimilar to trastuzumab (Herceptin) for the treatment of patients with HER2-overexpressing breast or metastatic gastric or gastroesophageal junction adenocarcinoma.^1,2 Trastuzumab-dkst has been approved as a biosimilar to U.S.-approved trastuzumab, not as an interchangeable product. Patients must be selected for therapy based on a U.S. Food and Drug Administration (FDA)-approved companion diagnostic for a trastuzumab product.

Basis for Approval

A biosimilar product is a biologic product approved based on data demonstrating it is highly similar to an FDA-approved biologic product, known as a reference product, and there are no clinically meaningful differences between the biosimilar product and the reference product. The biosimilarity of trastuzumab-dkst has been demonstrated for the condition(s) of use—eg, indication(s), dosing regimen(s), strength(s), dosage form(s), and route(s) of

administration—described in its full prescribing information. Approval was based on comparisons of extensive structural and functional product characterization, animal data, human pharmacokinetic and pharmacodynamic data, and clinical studies including clinical immunogenicity between trastuzumab-dkst and U.S.-licensed trastuzumab. These data demonstrate that trastuzumab-dkst is highly similar to U.S.-licensed trastuzumab, with no clinically meaningful differences between the products.

Safety Profile

As with trastuzumab, the most common expected adverse events with trastuzumab-dkst in the treatment of HER2-positive breast cancer include fever, chills, headache, infection, congestive heart failure, insomnia, cough, and rash. The most common expected adverse events in the treatment of metastatic gastric cancer include neutropenia, diarrhea, fatigue, anemia, stomatitis, weight loss, upper respiratory tract infections, fever,

thrombocytopenia, mucosal inflammation, nasopharyngitis, and dysgeusia. Serious expected side effects of trastuzumab-dkst include worsening of chemotherapy-induced neutropenia.

As with trastuzumab, trastuzumab-dkst has boxed warnings for cardiomyopathy, infusion reactions, pulmonary toxicity, and embryofetal toxicity and also carries warnings/precautions for exacerbation of chemotherapy-induced neutropenia. ■

REFERENCES

1. U.S. Food and Drug Administration: FDA approves Ogivri as a biosimilar to Herceptin. Available at www.fda.gov/Drugs/InformationOnDrugs/ApprovedDrugs/ucm587404.htm. Accessed December 21, 2017.

2. Ogivri (trastuzumab-dkst) for injection prescribing information, Mylan GmbH, December 2017. Available at www.accessdata.fda.gov/drugsatfda_docs/label/2017/761074s000lbl.pdf. Accessed December 21, 2017.