Background: DARA is a human, anti-CD38 IgGκ monoclonal antibody that significantly reduced the risk of progression/death with a manageable safety profile across several phase 3 studies in relapsed/refractory MM and NDMM. DARA + VRd (D-VRd) demonstrated efficacy and tolerability in the safety run-in cohort of the ongoing phase 2 GRIFFIN study that included transplant-eligible NDMM pts. To determine whether D-VRd demonstrates efficacy and tolerability in NDMM pts for whom transplant is not intended as initial therapy, the phase 3 CEPHEUS study will evaluate the efficacy and safety of D-VRd vs VRd alone in this pt population. Methods: This is an ongoing multicenter, open-label, randomized phase 3 study of D-VRd vs VRd alone in pts with NDMM for whom transplant is not intended as initial therapy. Approximately 360 pts will be stratified by ISS stage and age/transplant eligibility (age < 70 years and transplant-ineligible, or age < 70 years and refusal to transplant, or age ≥70 years) and will be randomized in a 1:1 ratio. All pts will receive eight 21-day cycles of VRd (V: 1.3 mg/m² SC Days 1, 4, 8, 11; R: 25 mg PO Days 1-14; d: 20 mg PO/IV Days 1, 2, 4, 5, 8, 9, 11, 12), followed by 28-day cycles of Rd (R: 25 mg PO Days 1-21; d: 40 mg PO/IV Days 1, 8, 15, 22) until progressive disease (PD). Patients in the DARA group will also receive subcutaneous DARA (1,800 mg co-formulated with recombinant human hyaluronidase PH20 [rHuPH20; Halozyme]) weekly in Cycles 1-2, every 3 weeks in Cycles 3-8, and every 4 weeks in Cycles 9+ until PD. All pts will receive preinfusion medications. Minimal residual disease (MRD)-negative rate at 10^–5 sensitivity threshold by NGS is the primary endpoint. MRD will be evaluated at suspected complete response or better. Secondary endpoints include progression-free survival (PFS), MRD-negative rate at 1-year, durable MRD negativity, overall response rate, time to and duration of response, PFS on next line of therapy, overall survival, clinical efficacy in high-risk molecular subgroups, health-related quality of life, pharmacokinetics, immunogenicity, and safety. Clinical trial information: NCT03652064