Anti-myeloma effects of the novel anthracycline derivative INNO-206

Doxorubicin has shown efficacy especially in combination treatment for the treatment of multiple myeloma; however, its side effects limit its use. INNO-206 is an albumin-binding prodrug of doxorubicin, which is released from albumin under acidic conditions. Because INNO-206 has not been previously evaluated in any hematologic malignancy, we determined its anti-multiple myeloma effects.

The anti-multiple myeloma effect of INNO-206 at different pH levels on multiple myeloma cell proliferation using multiple myeloma cell lines with the MTS assay and antiangiogenic activity using the chorioallantoic membrane/feather bud assay were determined. The anti-multiple myeloma effects and toxicity of INNO-206 were also compared with conventional doxorubicin and PEGylated liposomal doxorubicin (PLD) alone, and in combination with bortezomib, using our multiple myeloma xenograft models.

INNO-206 inhibited blood vessel formation and reduced multiple myeloma cell growth in a pH-dependent fashion. INNO-206 alone produced marked anti-multiple myeloma effects in vivo at doses that doxorubicin was toxic, and the combination of INNO-206 plus bortezomib produced increased anti-multiple myeloma effects compared with either agent alone. In contrast, all mice receiving bortezomib with doxorubicin or PLD died.

These findings show that INNO-206 produces anti-multiple myeloma effects in vitro and in vivo. It also enhances the antitumor effects of bortezomib. These results suggest that INNO-206 may provide patients with multiple myeloma with an anthracycline that may be administered safely at higher doses compared with free doxorubicin, resulting in superior efficacy compared with the currently available anthracyclines to treat this B-cell malignancy.