- Additional experimental anti-cancer treatment and/or standard chemo-, immunotherapy, hormone treatment (with the exception of megestrol acetate), or concurrent radiotherapy is not allowed concomitantly with the administration of study treatment (with the exception listed in section 9.0) 89Zr-trastuzumab use as imaging agent for 89Zr-trastuzumab PET permitted. Afatinib is a substrate of P-gp and its plasma concentrations can be affected by the use of P-gp inhibitors (data on file) and it is also likely that P-gp inducers could also influence afatinib plasma concentrations.