Abstracts Clinical Lymphoma, Myeloma & Leukemia September 2023 S494 Oncology, Memorial Sloan Kettering Cancer Center/Weill Cornell Medical College, New York, USA Context: Elranatamab, a bispecific antibody, targets BCMA on myeloma cells and CD3 on T cells. Objective: Evaluate efficacy and safety/tolerability of elranatamab in RRMM patients without prior BCMA-directed therapy. Design: MagnetisMM-3 (NCT04649359): open-label, non-randomized, Phase II. Setting: Multicenter. Patients: One hundred twenty-three patients refractory to ≥1 PI, ≥1 immunomodulatory drug, and ≥1 anti-CD38 antibody with 46 (efficacy) and 58 (safety) patients included in Q2W analyses. Interventions: Subcutaneous elranatamab in 28-d cycles (stepup doses, 12 mg [C1D1] and 32 mg [C1D4]; followed by 76 mg QW beginning C1D8). Patients treated for 6 cycles and achieving ≥partial response with response persisting ≥2 months switched to 76 mg Q2W. Main Outcome Measures: Objective response rate (ORR), minimal residual disease (MRD)-negativity, duration of response (DOR), progression-free survival (PFS), overall survival (OS), adverse events (AEs). Results: Median age, 68.0 years (range, 36−89); median prior lines of therapy, 5.0 (2−22); 96.7% and 42.3% of patients triple-class- and penta-drug refractory. At data cut-off (~12 months after last-patient-initial-dose), median follow-up, 12.8 months (0.2−22.7); 34.1% of patients remained on treatment. Most common reasons for permanent treatment discontinuation, progressive disease (39.0%) and AEs (13.8%). ORR per blinded independent central review was 61% (95% CI: 51.8−69.6), with 39 (31.7%) patients with complete response (CR)/stringent CR. MRDnegativity was achieved by 92.0% (n=23/25) of evaluable patients. Median DOR has not been reached (95% CI: 12.9−NE); DOR at 12 months, 74.1% (95% CI: 60.5−83.6). Among 46 patients who switched to Q2W dosing ≥24 weeks prior to the data cut-off, 80.4% maintained/improved their response ≥24 weeks after the switch. Median PFS/OS have not been reached; respective rates (95% CI) at 12 months, 57.1% (47.2−65.9) and 62.0% (52.8−70.0). Most common grade (G) 3/4 treatment-emergent AEs were hematologic; G3/4 non-hematologic events reported in ≥5% of patients were COVID-pneumonia (10.6%), hypokalemia (9.8%), pneumonia (7.3%), sepsis (6.5%), hypertension (6.5%), aminotransferase increased (5.7%), and SARS-COV-2 test positive (5.7%). Incidence of G3/4 AEs decreased by >10% among patients who switched to Q2W dosing (n=58). Conclusion: Elranatamab remains efficacious and well tolerated in RRMM patients after >1 year of follow-up. Updated analysis with a median follow-up of ~15 months will be presented. Keywords: MM, B-cell maturation antigen, bispecific, clinical trial, phase II MM-368 Iraqi Metadata Analysis of Diagnosis, Risk Stratification, and Management of Multiple Myeloma Najmaddin Khoshnaw MD2, Sara Abdulghani MBChB2, Rebar Mohammed PhD, MSc3,2 1Department of Medical Laboratory Science, Haematology Unit, College of science, Komar University of Science and Technology, Sulaymaniyah, Iraq. 2Hiwa Hospital, Sulaymaniyah, Iraq. 33Department of Microbiology, College of Veterinary Medicine, University of, Sulaymaniyah, Iraq Context: MM is a hematological disorder characterized by proliferation of clonal plasma cells and overproduction of monoclonal antibody paraproteins, which results in end organ damage. Objectives: In this metadata analysis, the diagnosis, risk stratifications and management of all MM patients treated in Iraq were reviewed. Design: Thirty-seven published articles were reviewed critically. Settings: MM is an aggressive disease and a limited study was published using data that originated from Iraqi cancer centers. This review article assists medical professions from Iraq to be aware of old and up-to-date scientific studies in the area. Patients or Other Participants: Multiple myeloma accounts for nearly 1.08–1.3% of all the cancers registered in Iraq in 2020. Nearly 440 new cases diagnosed and 367 died with MM in Iraq in 2020. Results: The annual crude rates of MM in various genders of male and females are accounted for 0.63 and 0.74/100,000 cases/ year respectively. The age-standardized incidence rates accounts for 7.8 and 9/100,000 cases/year in both males and females respectively. MM incidence rate is increased with rising age (mean 59 years old). The male to female ratio was 1.3/1. The commonest clinical presentation was backache, bone pain, fatigue, pallor and weight loss. We found that 45% of the cases were presented with stage III. The SPE showed immunoglobulin (Ig) G in 63%, IgA in 18%, light chain myeloma in 12%, nonsecretory multiple melanoma in 6%, and biclonal in 1% of cases. The common myeloma-defining events were lytic bone lesion (79%), anemia (76%), renal impairment (22%) and hypercalcemia in 12% of cases. There were reported data for correlation of poor prognosis with factors as high levels of each of hypercalcemia, interleukin 13, CD38, lactate dehydrogenase, CD34, serum GDF15, tumor necrosis factor-a, P53 mutation and finally low vitamin D. Most popular protocols used were bortezomib, lenalidomide and dexamethasone, bortezomib, thalidomide and dexamethasone, bortezomib and dexamethasone, bortezomib, cyclophosphamide and dexamethasone, bortezomib, melphalan and prednisone, melphalan-prednisone and vincristine, mitoxantrone, and dexamethasone. The mean survival of MM patients was 4.5 years and 72% of the MM patients had 3-year survival, which decreased to 41% for 6‑year survival. Conclusion: MM in Iraq is nearly similar to what has been published in other countries, despite minor differences. Keywords: MM, serum protein electrophoresis, CRAB MM-371 Pomalidomide, Daratumumab, and Dexamethasone After Lenalidomide Treatment in Patients With Relapsed or Refractory Multiple Myeloma (RRMM): Final Overall Survival (OS) Analysis of the Phase II MM‑014 Study Nizar J. Bahlis MD1, Christy Samaras DO2, Donna Reece MD, FRCPC3, Michael Sebag MD, PhD4, Jeffrey Matous MD5, Jesús G. Berdeja MD6, Jesse Shustik MD7, Gary J. Schiller MD8, Siddhartha Ganguly MD, FACP9,
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