valrubicin

Blend of val(erate) (“ester of valeric acid”) +‎ -rubicin (“daunorubicin derivative”).

However, the molecule is in fact a valerate analog of doxorubicin, not daunorubicin. Thus an etymology as val(erate) + (doxo)rubicin is plausible as well. See libfix for information on affixes such as -rubicin.