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.