A small peptide antagonist of integrin alpha5beta1 with potential antineoplastic activity. ATN-161 selectively binds to and blocks the receptor for integrin alpha5beta1, thereby preventing integrin alpha5beta1 binding. This receptor blockade may result in inhibition of endothelial cell-cell interactions, endothelial cell-matrix interactions, angiogenesis, and tumor progression. Integrin alpha5beta1 is expressed on endothelial cells and plays a crucial role in endothelial cell adhesion and migration. or A substance being studied in the treatment of certain multiple myelomas and other advanced cancers. Atiprimod may block the growth of tumors and may prevent the growth of new blood vessels that tumors need to grow. Atiprimod is a type of signal transduction inhibitor and a type of antiangiogenesis agent. Also called azaspirane and SK&F106615.