Genomic mechanisms of resistance to venetoclax in multiple myeloma with t(11;14)(CCND1;IGH) Available to Purchase

• RAS pathway mutations predict poor response and contribute to venetoclax resistance in t(11;14) multiple myeloma.

• Clonal evolution under venetoclax pressure favors selection of genomic complexity clones.

Multiple myeloma (MM) with t(11;14)(CCND1;IGH) remains the only subset sensitive to the BCL2 inhibitor venetoclax. Not all t(11;14)(CCND1;IGH) patients respond to treatment and some progress early after initial response. To investigate this, we interrogated 44 whole genome and exome sequencing data from 34 patients with t(11;14) MM treated with venetoclax. The presence of mutations in the RAS pathway was strongly associated with shortened progression-free survival (PFS) and was validated in an independent cohort of 21 MM patients. Presence of 1q gain was also associated with shorter PFS in patients without RAS mutations. In 10 patients with paired, pre- and post-venetoclax treatment samples, post-venetoclax progression was recurrently driven by the selection of genomic events in BCL2/MCL1 and RAS pathways and of high-risk features (e.g., loss of TP53 and CDKN2C). Overall, our study shows that comprehensive genomic profiling can identify most mechanisms underlying resistance to BCL2 inhibition in t(11;14)(CCND1;IGH) MM.