We previously reported that a monoclonal antibody (CBT-15) targeting a unique ECD region, termed the non-kinase extracellular binding domain (NKEBD), reduces PDAC tumor growth and disrupts tumorigenic signaling.7,13 Here, we extend these findings by developing a novel D-peptide that binds the NKEBD of DCLK1 isoform 4, inhibiting tumor growth in vitro and in vivo. Here, OPN1SW is linked to neoplasm.