Clinical Lymphoma, Myeloma & Leukemia, Vol.20, Suppl.1 - September 2020

Abstracts Clinical Lymphoma, Myeloma & Leukemia September 2020 S306 were 75% and 89%, respectively. A stringent CR was achieved in 62.5% of patients. Myeloma progression was noted in 2 cases against the background of 100% donor bone marrow chimerism. Severe acute GVHD was observed in 25% of cases. The high frequency of GVHD requires close monitoring and timely treatment. The transplant-related mortality rate was 12.5%. Keywords: multiple myeloma, allogeneic hematopoietic stem cell transplant, allo-HSCT, high-risk, progression, acute GVHD, transplant-related mortality, MM MM-296 A Real - W o rld S t udy o f Pan o bin o s t a t , Weekly B o r t e zo mib, and D exame t has o ne in a Very Heavily Pre - Trea t ed P o pula t i o n o f Mul t iple Myel o ma Pa t ien t s Sarah Bird 1,2 *, Charlotte Pawlyn 1,2 , Susanna Nallamilli 3 , Priya Sriskandarajah 1 , Martin Kaiser 1,2 , Kwee Yong 3 , Rakesh Popat 3 , Neil Rabin 3 , Kevin Boyd 1,2 1 The Royal Marsden Hospital NHS Foundation Trust, London, 2 The Institute of Cancer Research, London, 3 University College London Hospital NHS Foundation Trust, London Context: In the UK, treatment with panobinostat, bortezomib, and dexamethasone (PAN-Vd) is often positioned as a fifth- line therapy, but there is little published experience of its use in such heavily pre-treated patients. Objective: Assessment of the efficacy and toxicity of PAN-Vd in the real-world setting. Design: Retrospective case-review study including patients commenced on PAN-Vd April 2016–March 2019 (follow-up until December 2019). Setting: Two UK tertiary MM centres: The Royal Marsden Hospital (RMH) and University College London Hospital. Patients: Seventy-five patients received PAN-Vd, with a median of four prior lines of therapy (range 2–8). Fifty-one percent (38/75) were PI refractory. Cytogenetic data were available in 44; 77% (34/44) had high-risk disease. Interventions: Bortezomib was given at 1.3 mg/ m 2 weekly D1, 8, 15, 22; panobinostat 20 mg D1, 3, 5,15, 17,19; dexamethasone 20–40mg D1, 8,15, 22. Main outcome measures: The primary objective was to assess the overall response rate (ORR) and clinical benefit rate (CBR). Secondary objectives included calculation of progression-free survival (PFS) and overall survival (OS) and assessment of toxicity. Results: ORR was 47% (34/73), and CBR was 60% (44/73). The median PFS was 3.5 months (median follow-up 26 months), and the OS was 10 months (follow- up 38 months). Achievement of  PR was associated with longer PFS and OS (median PFS 6.2 months vs 1.5 months, p<0.001; OS 13 months vs 5.4 months, p=0.007). The presence of high-risk disease compared to non-high-risk disease showed a trend towards shorter PFS and OS (median PFS 2.5 months vs 5.4 months, p=0.098; OS 9.3 months vs 18 months, p=0.151). Patients who were previously refractory to PI therapy had a significantly shorter PFS and OS than those not previously refractory (median PFS 1.5 months vs 5.3 months, p=0.008; OS 7.6 months vs 12.6 months, p=0.040. Toxicity data were collected for the 45 patients treated at RMH. Twenty-four percent (11/45) received  8 cycles, and 27% (12/44) stopped treatment due to toxicity. The main adverse events were haematological, and 84% (38/45) required transfusion of platelets and/or red cells. Conclusions: PAN-Vd can be effective for a subset of heavily pre-treated patients. Specific benefit was seen in patients who were not refractory to PIs and responding patients. However, the regimen was associated with significant toxicity. Keywords: multiple myeloma, MM, relapsed, refractory, panobinostat MM-339 E ffec t o f Lenalid o mide (R) ± D exame t has o ne (d) D isc o n t inua t i o n o n D ara t umumab E f fi cacy in Mul t iple Myel o ma (MM) : Subgr o up Analysis o f t he Phase 3 MAIA and P O LLUX S t udies Philippe Moreau 1 *, Thierry Facon 2 , Saad Z. Usmani 3 , Meletios Dimopoulos 4 , Shaji Kumar 5 , Torben Plesner 6 , Hartmut Goldschmidt 7 , Donna Reece 8 , Robert Z. Orlowski 9 , Aurore Perrot 10 , Merav Leiba 11 , Ajai Chari 12 , Jesus San-Miguel 13 , Gordon Cook 14 , Shinsuke Iida 15 , Huiling Pei 16 , Rian Van Rampelbergh 17 , Clarissa M. Uhlar 18 , Thomas Renaud 19 , Jon Ukropec 20 , Rachel Kobos 19 , Nizar Bahlis 21 1 Hematology, University Hospital Hôtel-Dieu, Nantes, France, 2 Service des Maladies du Sang, Hôpital Claude Huriez, Lille, France, 3 Levine Cancer Institute/Atrium Health, Charlotte, NC, USA, 4 National and Kapodistrian University of Athens, Athens, Greece, 5 Department of Hematology, Mayo Clinic Rochester, Rochester, MN, USA, 6 Vejle Hospital and University of Southern Denmark, Vejle, Denmark, 7 University Hospital Heidelberg and National Center of Tumor Diseases (NCT), Heidelberg, Germany, 8 Cancer Clinical Research Unit, Princess Margaret Cancer Centre, Toronto, Canada, 9 Department of Lymphoma-Myeloma, University of Texas M.D. Anderson Cancer Center, Houston, TX, USA, 10 Hematology Department, University Cancer Institute IUCT, Toulouse, France, 11 Assuta University Hospital, Faculty of Health Science, Ben-Gurion University of the Negev, Beersheba, Israel, 12 Icahn School of Medicine at Mount Sinai, New York, NY, USA, 13 Clínica Universidad de Navarra-CIMA, IDISNA, CIBERONC, Pamplona, Spain, 14 St James’s Institute of Oncology, Leeds Teaching Hospitals NHS Trust and University of Leeds, Leeds, UK, 15 Department of Hematology and Oncology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan, 16 Janssen Research & Development, LLC, Titusville, NJ, USA, 17 Janssen Research & Development, Beerse, Belgium, 18 Janssen Research & Development, LLC, Spring House, PA, USA, 19 Janssen Research & Development, Raritan, NJ, USA, 20 Janssen Global Medical Affairs, Horsham, PA, USA, 21 University of Calgary, Arnie Charbonneau Cancer Institute, Calgary, AB, Canada Context: Daratumumab (D), is approved as monotherapy and combination therapy for MM. We report an analysis of patients who discontinued R±d in the D-Rd arm of the MAIA and POLLUX studies. Design: In MAIA and POLLUX, patients with transplant- ineligible newly diagnosed MM and relapsed/refractory MM,