Dolastatin 15 shows growth inhibitory activity against all four SCLC cell lines (NCI-H69, NCI-H82, NCI-H345, NCI-H446) (IC50: 0.039-28.8 nM), which were 2.7-9.2-fold higher than the values for dolastatin 10. Dolastatin 15 induces cell cycle arrest at the G2/M phase followed by apoptosis in various human myeloma cell lines (RPMI8226, U266, and IM9) and it also induces apoptosis of myeloma cells via activation of both mitochondrial- and Fas (CD95)/Fas-L (CD95-L)-mediated pathways [2]. All four SCLC cell lines underwent G2/M arrest within 24 hours of exposure to dolastatin 15 [4].

Dolastatin 15, using a non-cleavable linker, conjugates to Trastuzumab via lysine residues at the drug C-terminus. Trastuzumab-amide-C-term-Dol15 produced target-dependent growth inhibition of cells endogenously expressing high HER2 levels (i.e., SK-BR-3, SK-OV-3) in vitro. This ADC was effective at varying doses (i.e., 10 and 20 mg/kg) in the SK-OV-3 human ovarian cancer xenograft [3].