On Feb. 28, 2019, the U.S. Food and Drug Administration (FDA) approved trastuzumab and hyaluronidase-oysk injection,for subcutaneous use (Herceptin Hylecta, Genentech). Herceptin Hylecta is a combination of trastuzumab, a HER2/neu receptor antagonist, and hyaluronidase, an endoglycosidase, for the treatment of HER2-overexpressing breast cancer.

Approval was based on two randomized trials, HannaH and SafeHER. In HannaH, 596 patients with HER2-positive operable or locally advanced breast cancer, including inflammatory breast cancer, were randomized to receive 8 cycles of either Herceptin Hylecta or intravenous trastuzumab concurrently with chemotherapy, followed by surgery and continued therapy with either Herceptin Hylecta or intravenous trastuzumab, for an additional 10 cycles.

HannaH demonstrated comparability between Herceptin Hylecta and intravenous trastuzumab based on co-primary endpoints of pathologic complete response and pharmacokinetics.