Background: The most common translocation in multiple myeloma (MM) is t(11;14)(q13;q32), present in approximately 20% of cases. MM cells with t(11;14) usually have a favorable high BCL-2 level and inferior outcomes compared to standard risk MM. Venetoclax (VEN) is a potent, selective, orally available small-molecule BCL-2 inhibitor that induces cell death in MM cell lines and primary samples. VEN has single agent activity in relapsed/refractory MM (RRMM) with an acceptable safety profile, especially in t(11;14) MM; however, non- t(11;14) MM patients may benefit from single agent VEN and VEN incorporated in multi-agent RRMM regimens. Dexamethasone (d) promotes Bcl-2 dependence in MM resulting in sensitivity to VEN and this combination with bortezomib (Vd-VEN) has an acceptable safety profile with high response rates in heavily pre-treated MM. Combination therapy with daratumumab and bortezomib (DVd) has become a standard of care in RRMM. Our hypotheses are that the addition of VEN will improve upon this standard and be most effective in the t(11;14) positive subset. Methods: Eligibility criteria include RRMM with measurable disease, not bortezomib refractory, platelet count > 100K. t(11;14) is an integral biomarker with status (positive or negative) established at registration. After a Ph1 study to determine the recommended phase 2 VEN dose, patients are randomized to DVd +/- VEN [stratified by prior lines of therapy and R-ISS]. The primary Ph2 objectives are to compare 8-cycle minimal residual disease (MRD) negative rate and to inform the role of t(11;14) as a biomarker. The Ph2 design proposed by Freidlin et al. follows a decision algorithm as outlined in the table below. Simulations were run to establish an optimal sample size given various parameters including biomarker prevalence and power to make appropriate decisions for a Ph3 design. Target Ph2 accrual is 240 patients with a 1/3 positive:2/3 negative t(11;14) split. Clinical trial information: NCT03701321