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TAPUR is a pragmatic, phase II basket study evaluating the antitumor activity of commercially available targeted agents in patients with advanced cancers harboring genomic alterations known to be drug targets. Sunitinib is an oral multikinase inhibitor of FMS-like tyrosine kinase-3 (FLT-3), among other targets. Results from a cohort of patients with metastatic colorectal cancer (mCRC) with FLT-3 amplification treated with sunitinib are reported. This study aimed to investigate whether patients with mCRC with FLT-3 amplification would be responsive to sunitinib, an oral multikinase inhibitor. Eligible patients received a standard sunitinib dose of 50 mg orally for 4 weeks followed by 2 weeks off. Simon’s two-stage design was used with the primary study endpoint of objective response (OR) or stable disease (SD) at 16 weeks based on Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. Secondary endpoints were progression-free survival, overall survival, and safety. Ten patients were enrolled from November 2016 to April 2018. All patients had mCRC with FLT-3 amplification. No ORs were observed. Although two patients had SD at 16 weeks, one died because of disease progression shortly thereafter and the cohort was closed. A single grade 3 adverse event of diarrhea was reported as possibly related to sunitinib. Monotherapy with sunitinib does not have clinical activity in patients with mCRC with FLT-3 amplification and should not be prescribed for off-label use. Other treatments should be considered for these patients, including treatments offered in clinical trials. NCT02693535 (26 February 2016).

Approximately 15-20% of all breast cancers are human epidermal growth factor receptor 2 (HER2) positive, with clinical studies having validated the HER2 receptor tyrosine kinase pathway as an important therapeutic target. Presently, two HER2-targeted therapies are approved by the Food and Drug Administration for treatment of HER2-positive breast cancer: the HER2-targeted humanized monoclonal antibody trastuzumab and the small-molecule tyrosine kinase inhibitor lapatinib. Despite use of these HER2-targeted agents, many patients still experience disease progression. For this reason, numerous new agents and therapeutic strategies are under investigation. Based on preclinical data suggesting synergistic effects from dual therapy targeting HER2, clinical trials that test the effects of combining anti-HER2 agents have been conducted and are ongoing. Here, we review recently presented data from several clinical trials, which indicate that the strategy of combining HER2 blockade therapies can offer greater clinical efficacy, with adverse effects of varying degrees. Specifically, we review new data reported at the 2010 San Antonio Breast Cancer Symposium (SABCS 2010), including the phase II NeoSphere and phase III NeoALTTO clinical trials, and data from three clinical trials reported at the 2011 American Society of Clinical Oncology (ASCO 2011) meeting. Together these trials elucidate the potential role of combining trastuzumab with lapatinib or pertuzumab. We also discuss additional ongoing studies that will help further define the role of dual HER2 blockade therapies and its impact on clinical practice.