Neo-adjuvant and/or Adjuvant Subcutaneous Trastuzumab (Herceptin®) in Patients With Early HER2-positive Breast Cancer: Real World Data from a German Observational Study - (NIS HerSCin).

Background/aim Subcutaneous Herceptin (HER SC) has been shown to be equally effective and safe compared to intravenous Herceptin (HER i.v.) application in early HER2-positive breast cancer (HER2+ BC). However, real-world data from the subcutaneous application are currently limited. Patients and methods Based on a non-interventional study (NIS), data from routine clinical use of HER SC have been gathered between 2013 and 2018 in 135 hospitals and open-care practices throughout Germany. Results A total of 265 patients were recruited in the neo-adjuvant and 605 patients in the adjuvant setting. Primary effectiveness endpoint in the neoadjuvant treatment setting was pathological complete response rate, which was achieved in 41.5%. Primary endpoint in the adjuvant setting was disease free survival rate after 2 years (94.9%). Safety results from the study were comparable to the well-known safety profile of HER i.v. including preferred terms, incidence, severity, including cardiac events. No new safety signals were detected. Conclusion Effectiveness and safety of HER SC were comparable to data from HER i.v. in early HER2+ BC.