Background: Intravenous (IV) administration of DARA 16 mg/kg is approved as monotherapy and in combination with standard of care regimens for RRMM. The phase 1b PAVO study (NCT02519452) demonstrated that delivery of DARA with recombinant human hyaluronidase enzyme (rHuPH20) by subcutaneous (SC) infusion through a syringe pump (Part 1) or by manual SC injection (Part 2) was well tolerated with an efficacy profile consistent with IV DARA (Chari A, et al. ASH 2017; abstract 838). We present updated data from Part 2. Methods: Eligible pts received ≥2 prior lines of therapy (LOTs) including a proteasome inhibitor and an immunomodulatory drug. In Part 2, pts received a concentrated co-formulation of DARA (DARA SC; 1,800 mg in 15 mL) and rHuPH20 (30,000 U) dose in a single, pre-mixed vial, which was administered in 3 to 5 minutes by manual SC injection. Primary endpoints were C_trough of DARA at the end of weekly dosing on Cycle 3 Day 1 (C3D1) and safety. Secondary endpoints included overall response rate (ORR), rate of complete response, time to response, and duration of response. Results: Pts in Part 2 (n = 25) had a median age of 68 years and received a median of 3 prior LOTs. At a median follow-up of 4.6 months, none discontinued due to treatment-emergent adverse events (TEAEs). Pharmacokinetic analyses indicated that DARA SC had a T_max of approximately 72 h and achieved similar or greater C_trough on C3D1 compared to what has been observed with DARA IV. Most common Grade 3/4 TEAEs ( > 1 pt) were lymphopenia (16%), thrombocytopenia (8%), and neutropenia (8%). IRRs were reported in 3 (12%) pts, all occurring ≤6 h of the first injection. No grade 4 IRRs or discontinuations due to IRRs occurred. DARA SC injections in the periumbilical area were well tolerated with reversible erythema observed in 20% of pts. DARA SC achieved an ORR of 44%, including 28% ≥very good partial response. Conclusions: DARA SC, which enables dosing in 3-5 minutes, was well tolerated with low IRR rates, had an acceptable PK profile, and demonstrated clinical response rates similar to DARA-IV. Updated data based on longer follow-up will be presented at the meeting. Clinical trial information: NCT02519452