Venetoclax-based Therapy Improves Outcomes across the Evolving Biology of t(11;14) Multiple Myeloma

Background: Translocation t(11;14) defines a biologically distinct subset of multiple myeloma (MM) enriched for BCL2 dependency. Treatment with venetoclax, selective BCL2 inhibitor, has shown varied responses in clinical trials and retrospective cohorts. Efficacy of venetoclax-based combination therapies and optimal timing of treatment in t(11;14) MM patients remain incompletely characterized. Methods: We have compared the overall survival of t(11;14) MM patients who received Venetoclax (N = 97) at any moment in time, to those who never did (N =284), in the largest retrospective cohort (N = 381) reported to date. We used longitudinal fluorescence in situ hybridization (FISH) to assess cytogenetic evolution and genomic complexity. We performed transcriptomic profiling of CD138 enriched tumors using RNA sequencing in a subset of samples and gene expression signatures (UAMS/HALLMARKS) were used to define molecular subtypes. Ex vivo drug sensitivity assays integrated with paired RNA sequencing were used to identify subtype specific therapeutic vulnerabilities and rational venetoclax based combination strategies. Results: Venetoclax exposure was associated with an improvement of median overall survival by nearly four years compared to non VEN exposed patients (p = 0.0003). Longitudinal cytogenetic analysis demonstrated stability of the primary t(11;14) translocation over time, while secondary abnormalities tend to accumulate, including those harboring high-risk secondary cytogenetic abnormalities such as del13q, amp/gain1q21, del17p, and del1p, resulting in increasing genomic complexity with disease progression. Transcriptomic analyses identified selective enrichment of CD1/CD2 signature (associated with t(11;14) NDMM) by single sample gene set enrichment analysis as a marker of prolonged progression free survival. However, patients with more than five prior lines of therapy were enriched for transcriptionally complex biology characterized by CD1/CD2 with either proliferative/hypermetabolic or inflammatory transcriptional programming which were associated with inferior outcomes with VEN based treatment. Ex vivo drug sensitivity profiling revealed subtype specific vulnerabilities, identifying daratumumab, lenalidomide, ixazomib, and panobinostat as rational partners for venetoclax depending on transcriptional context. Conclusion: Venetoclax-based therapy significantly improved overall survival in t(11;14) MM. Clinical benefit, defined by improved progression free survival, was greatest when venetoclax was administered earlier, preceding the emergence of transcriptomic reprogramming that reduces BCL2 dependency. These findings support transcriptomic biomarker guided, subtype specific venetoclax based treatment strategies to optimize outcomes in patients with t(11;14) MM.