EGF105084, a phase II study of lapatinib for brain metastases in patients (pts) with HER2+ breast cancer following trastuzumab (H) based systemic therapy and cranial radiotherapy (RT)

1012 Background: CNS disease is a major problem among pts treated with H for stage IV HER2+ breast cancer with a reported incidence of 28–43%. This study was designed to characterize further the activity reported with lapatinib in an initial phase II trial in women with HER2+ disease metastatic to brain (Lin et al ASCO ‘06). Methods: Eligible pts had HER2+ breast cancer, prior H therapy and cranial RT, ECOG PS 0–2, and radiographic evidence of progressive brain metastases with at least one measurable (LD = 10mm) brain lesion. Pts received lapatinib 750 mg PO BID. Brain MRIs were obtained at 3.0 mm slices without gaps in the axial dimension. The primary endpoint was CNS response as defined by a = 50% volumetric (vol) reduction of CNS lesions in the absence of: new lesions, need for increased dose of steroids, progressive neurological signs/symptoms (NSS), or progressive extra-CNS disease. CNS disease progression was defined as either a = 40% vol increase from nadir, increase in steroid requirements, or pro...