Observation Following Subcutaneous Trastuzumab Administration Unnecessary

Extended observation for adverse reactions following subcutaneously administered trastuzumab (Herceptin, Genentech/Roche) serves as an unnecessary use of health care resources, according to the results of a single-institution study.

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Trastuzumab is a commonly used treatment for women with human epidermal growth factor receptor 2–positive breast cancer, as well as patients with stomach cancer and esophageal cancer. The randomized, phase 3 HannaH study found that subcutaneous administration was noninferior to intravenous (IV) administration.

Although subcutaneous administration has not been associated with major administration-related reactions—such as hypotension or respiratory distress—the summary of product characteristics recommends that patients whose trastuzumab is administered subcutaneously be monitored for 6 hours following their first injection, and for 2 hours following each subsequent injection.

Researchers from Bon Secours Hospital (Cork, Ireland) followed 39 patients receiving subcutaneously administered trastuzumab. Of this cohort, 32 patients previously received IV trastuzumab. Patients on study received a total of 470 subcutaneous injections (mean, n = 12), which represented a total of 1096 hours of observation.

Providers used medical notes to record adverse events occurring following the first subcutaneous administration, and after all subsequent administrations. Patients were further reached by telephone and interviewed about date and severity of adverse events.

Three injections resulted in adverse reactions within 24 hours of administration (0.6%). All administration-related reactions occurred during the first treatment cycle. Two patients experienced adverse reactions immediately following administration; one additional patient experienced injection-site pain during administration.

One patient was subsequently hospitalized with a respiratory tract infection, after experiencing pyrexia and a cough that persisted for 24 hours postinjection. However, no patient experienced adverse reactions at 2 hours or 6 hours postinjection, and no observed reactions were serious.

“Administration-related reactions related to subcutaneous trastuzumab are usually immediate, mild, and self-limiting,” the researchers wrote. “Observing patients for 6 hours postinjection and 2 hours after each subsequent injection represents an inefficient use of health care resources.”