Trastuzumab; is there an easier, more pain-free method of administration?

This paper reviews the use of subcutaneous trastuzumab. 

The human epidermal growth factor receptor 2 (HER2) is a protein involved in tumour cell growth and division. HER2 is associated with more aggressive disease and is a target for therapy. Trastuzumab (Herceptin) targets HER2 and is approved for use in breast cancer. Until recently, intravenous infusion (straight into the vein) was the only way of administering trastuzumab. Now, trastuzumab is can be administered subcutaneously (into the fat layer below skin). This can be cheaper, safer, and more convenient than intravenous infusion. Subcutaneous trastuzumab is approved for use in patients with HER2 present and early or metastatic (cancer that spreads to other regions) breast cancer. 

Intravenous trastuzumab is effective as it prolongs disease-free survival (no symptoms of cancer). A study comparing subcutaneous trastuzumab with intravenous trastuzumab gave similar results for both methods. This indicates that subcutaneous trastuzumab is an alternative to intravenous trastuzumab. In another study, 45.4% of patients receiving subcutaneous trastuzumab and 40.7% of intravenous  trastuzumab recipients had a complete disappearance of signs or symptoms of cancer. This suggests both methods have similar effectiveness.

Patients generally preferred subcutaneous treatment. Based on one study, 84% of patients preferred subcutaneous administration over intravenous administration, mainly due to the fact that it was time-saving and caused less pain and discomfort.

How well patients tolerated trastuzumab was also studied. In one study, 94% of subcutaneous  trastuzumab and 97% of intravenous trastuzumab recipients had at least one adverse event. Adverse events occurring in more than 25% of patients were hair loss, nausea, a low number of white blood cells, diarrhea, weakness and fatigue. Two of three deaths in patients receiving subcutaneous trastuzumab were considered treatment related. 21% of subcutaneous trastuzumab and 12% of intravenous trastuzumab recipients had a serious adverse event. In another study, adverse events were reported by 58% of subcutaneous trastuzumab and 44% of intravenous trastuzumab recipients. 

The authors conclude that subcutaneous trastuzumab is a viable alternative to intravenous infusion.