Combined physicochemical and functional assessment of pertuzumab integrity supports extended in-use stability.

Pertuzumab (Perjeta®) is a monoclonal antibody approved for the treatment of HER2-positive breast cancer. Before treatment, the concentrate must be diluted to obtain the ready-to-use infusion solution. Data on the storage stabilities of these preparations are lacking but important for all healthcare professionals in the area of outpatient chemotherapy. The aim of this study was to investigate the storage stability of the ready-to-use infusion bags and the concentrates from once-opened vials over a period of up to 42 days. For a comprehensive and unambiguous assessment of pertuzumab's integrity, a panel of orthogonal analytical methods was employed, including a newly established mass spectrometry-based peptide mapping procedure along with a reporter gene assay for monitoring cellular bioactivity. The herein presented data showed that the ready-to-use infusion solutions stored at 4 ± 2°C and at 20 ± 3°C without light protection, as well as the undiluted Perjeta® concentrates stored at 4 ± 2°C, were physicochemically stable and biologically active for 28 days. These results might eventually allow for infusion preparations in advance, thus improving the quality of patient care as well as the economic usage of pertuzumab.