INNO-206 (Aldoxorubicin) is the 6-maleimidocaproyl hydrazone derivative prodrug of the anthracycline antibiotic doxorubicin (DOXO-EMCH) with antineoplastic activity. Following intravenous administration, doxorubicin prodrug INNO-206 binds selectively to the cysteine-34 position of albumin via its maleimide moiety. Doxorubicin is released from the albumin carrier after cleavage of the acid-sensitive hydrazone linker within the acidic environment of tumors and, once located intracellularly, intercalates DNA, inhibits DNA synthesis, and induces apoptosis. Albumin tends to accumulate in solid tumors as a result of high metabolic turnover, rapid angiogenesis, hyervasculature, and impaired lymphatic drainage. Because of passive accumulation within tumors, this agent may improve the therapeutic effects of doxorubicin while minimizing systemic toxicity. In a phase I study, INNO-206 showed a good safety profile at doses up to 260 mg/m2 doxorubicin equivalents. Although not the primary end point of the phase I study, INNO-206 was able to induce tumor regressions in breast cancer, small cell lung cancer and sarcoma.