The U.S. Food and Drug Administration (FDA) has approved trastuzumab-strf (Hercessi), a biosimilar to trastuzumab (Herceptin), for the treatment of HER2-overexpressing breast cancer and gastric or gastroesophageal junction adenocarcinoma.
Trastuzumab-strf is indicated for adjuvant treatment of HER2-overexpressing breast cancer, the treatment of HER2-overexpressing metastatic breast cancer, and the treatment of HER2-overexpressing metastatic gastric or gastroesophageal junction adenocarcinoma. HER2 cancers in general are particularly aggressive malignancies that respond well to targeted treatment. Trastuzumab-strf works by binding to and inactivating the HER2 receptor, slowing down cell replication.
FDA approval was granted based on a comprehensive package of analytical, preclinical, and clinical data, which showed trastuzumab-strf and its reference product, trastuzumab are highly similar in terms of efficacy, safety, and quality. The clinical program for trastuzumab-strf included three studies conducted since 2015 to demonstrate pharmacokinetic comparability and clinical efficacy/safety similarity between trastuzumab-strf and its reference product.
The studies include two phase I comparative single-dose pharmacokinetic equivalence studies conducted in healthy volunteers (HLX02-HV01 and HLX02-HV02), and a supportive phase III, double-blind, randomized clinical efficacy and safety comparability study in patients with HER2-overexpressing metastatic breast cancer in combination with docetaxel (HLX02-BC01). The pharmacokinetic comparability and clinical efficacy/safety similarity exercised in HLX02-HV02 and HLX02-BC01 adheres to current biosimilar guidance from the FDA.
The safety profile of trastuzumab-strf has been shown to be consistent with the safety profile for the reference product trastuzumab. The data demonstrate that there are no clinically meaningful differences between trastuzumab-strf and trastuzumab in the populations studied, and support biosimilarity between the two therapies.
Trastuzumab-strf was approved by the FDA at a dosage of 150 mg. A 420-mg version of trastuzumab-strf is also in development, with an FDA decision anticipated later in 2024.
