Safety assessment of trastuzumab diluted in 100 ml of saline in the treatment of HER2-positive breast cancer patients.
e11555 Background: The infusion rate is considered to affect incidence and severity of infusion reaction (IR) caused by infusion of protein formulations. Trastuzumab (TRS) is approved for 90-minute infusion as the initial dose followed by 30-minute infusion with 250 ml saline. We evaluated the safety of TRS intravenously administered over 30minutes with 100 ml saline to reduce burden of patients although safety of infusion with 250 ml saline is established. Methods: Women with HER2 positive breast cancer, ≥18 years and ≥55% left ventricular ejection fraction (LVEF) were registered in the study. Patients received 8mg/kg of TRS 250 ml over 90 minutes diluted in 250 ml saline followed by 6mg/kg of TRS in 100 ml saline over 30 minutes in a three-week cycle. The primary endpoint of this study was the incidence of infusion reactions, and secondary endpoints were as follows: incidence of adverse events and effects on cardiac function. Results: Between June 2011 and June 2012, a total of 31 patients were recruited; 24 for adjuvant therapy and seven with metastases. The median age was 59 years (range, 39 to 82). Hormone receptor was positive in 18 patients (58%). Previous treatment with anthracyclines was reported in seven patients and radiation therapy in fourteen patients. The total number of TRS doses ranged from 5 to 17 with the median of 15. Mild IR occurred in two patients and rash occurred in one patient at the first dose. However, no IR and adverse events were observed after reducing to 100 ml saline. The average LVEF measured every 3 months was between 62.3% and 64.8%. No significant decrease in LVEF was reported with the largest decrease of 8% in one patient at the 12th month on treatment. Conversely, brain natriuretic peptide levels tended to decrease as the number of received doses increased. None of the subgroup analysis (age groups, adjuvant vs. metastatic setting, previous anthracycline treatment, and previous radiotherapy) showed statistical significance. Conclusions: Intravenous infusion of TRS with 100 ml saline over 30 minutes in breast cancer patients is considered safe based on results from the study. The safe treatment with shorter infusion time has benefit for both healthcare professionals and patients. Clinical trial information: UMIN000006710.