Myeloma: Therapy, excluding Transplantation: Antibodies and Targeted Therapies

595  Preliminary Results from a Phase I Study of Isatuximab (ISA) in Combination with Bortezomib, Lenalidomide, Dexamethasone (VRd) in Patients with Newly Diagnosed Multiple Myeloma (NDMM) Non-Eligible for Transplant

Enrique M. Ocio, et al.

The Abstract concludes: These data suggest that ISA plus VRd followed by ISA plus Rd is well tolerated with a high ORR of 93%. All responders had VGPR or CR except 1 pt with PR. Quality of CR may have been underestimated due to ISA interference which could be resolved with an interference assay.

596  Efficacy and Tolerability of Ixazomib, Daratumumab and Low Dose Dexamethasone (IDd) in Unfit and Frail Newly Diagnosed Multiple Myeloma (NDMM) Patients; First Interim Safety Analysis of the Phase II HOVON 143 Study

Claudia A.M. Stege, et al.

The Abstract concludes: This planned safety analysis of frail patients in the HOVON 143 showed that Ixazomib-Daratumumab-low dose dexamethasone is feasible with a low rate of therapy-related toxicity and mortality. Preliminary response rates are promising.

597  Atezolizumab in Combination with Daratumumab with or without Lenalidomide or Pomalidomide: A Phase Ib Study in Patients with Multiple Myeloma

Hearn Jay Cho, MD,et al.

The Abstract concludes: Atezo plus dara and in combination with len or pom demonstrated acceptable tolerability; no new safety signals were identified. Some pts treated with either atezo plus dara or atezo plus dara and IMiD appeared to have deep and durable responses. The benefit-risk profile of atezo in combination with dara with/without pom in R/R MM pts is promising. These early data support continuation of the study.

598  Results of the Pivotal STORM Study (Part 2) in Penta-Refractory Multiple Myeloma (MM): Deep and Durable Responses with Oral Selinexor Plus Low Dose Dexamethasone in Patients with Penta-Refractory MM

Ajai Chari, MD, et al.

The Abstract concludes: Results of the pivotal STORM Part 2 in penta (PI, IMiD, dara)-refractory MM demonstrated that oral selinexor plus low-dose dexamethasone (Sd) was highly active with an ORR of 26.2%. Importantly, responses were rapid and deep with 2 patients achieving sCRs (both MRD negative) in these heavily pre-treated penta-refractory MM pts (median 7 prior regimens, 53% high risk). AEs are a function of dose/schedule/disease severity and can be managed with dose modifications and supportive care. No major organ toxicity was observed and AEs were typically transient and reversible. Sd is an all-oral, first in class mechanism with novel MOA and represents a potential therapeutic option to the growing number of pts with penta-refractory MM who have exhausted approved therapies.

599  Deep and Durable Responses with Selinexor, Daratumumab, and Dexamethasone (SDd) in Patients with Multiple Myeloma (MM) Previously Exposed to Proteasome Inhibitors and Immunomodulatory Drugs: Results of Phase 1b Study of Sdd

Cristina J Gasparetto, et al.

The Abstract concludes: Selinexor 100 mg QW can be combined safely with dara (per approved dosing) and dex. The preliminary ORR of 74% with SDd in patients with PI/IMiD refractory MM who are dara naïve is promising and compares favorably to 21% ORR of Dara and Sd in quad refractory myeloma. This once weekly regimen is well tolerated with no major organ toxicities to date. Data from the full phase 1 dose expansion will be presented.

600  OP-106 Horizon - Melflufen Therapy for RRMM Patients Refractory to Daratumumab and/or Pomalidomide; Updated Results and First Report on PFS

Paul Richardson, et al.

The Abstract concludes: Melflufen has promising activity in heavily pre-treated and refractory late stage RRMM pts, in whom the majority of available, approved and experimental therapies have failed. Analysis of the preliminary efficacy results showed an encouraging ORR of 32% and a CBR of 39% in a population with a median of 5.5 prior lines of therapy, including 54% with high-risk cytogenetics. Melflufen was generally well tolerated with discontinuation due to AE in only 15% of pts. Thrombocytopenia and neutropenia were the most frequent AEs and non-hematologic AEs were infrequent. Updated data, including PFS and DOR, will be presented at the meeting.