In summary, these results indicate that germline mutations in RTKs might be of prognostic relevance in MM. PO-004 Minimal Residual Disease in Transplant Ineligible Myeloma Patients: Results from the UK NCRI Myeloma XI trial R. de Tute, 1 A.C. Rawstron, 1 D. Cairns, 2 C. Pawlyn, 3 F. Davies, 3,4 C. Collett, 2 J. Jones, 3 M. Kaiser, 3 A. Chalmers, 2 A. Striha, 2 G. Cook, 1 N. Russell, 5 M.T. Drayson, 6 W.M. Gregory, 2 G.H. Jackson, 7 G.J. Morgan, 3,4 R.G. Owen 1 1 St James’s University Hospital, Leeds, UK; 2 Clinical Trials Research Unit, University of Leeds, Leeds, UK; 3 Institute of Cancer Research, London, UK; 4 University of Arkansas for Medical Sciences, Little Rock, USA; 5 Nottingham University Hospitals NHS Trust, Notting- ham, UK; 6 University of Birmingham, Birmingham, UK; 7 University of Newcastle, Newcastle, UK Introduction: Minimal residual disease (MRD) is a powerful predictor of outcome in multiple myeloma (MM). We have previously demonstrated, in transplant eligible patients, that the level of MRD as a continuous variable independently predicts both PFS and OS, with approximately one year median OS benefit per log depletion. There is more limited data on the applicability of MRD assessment in transplant ineligible pa- tients, largely as a consequence of low rates of CR historically within this patient cohort. Patients and Methods: In this analysis we have chosen to assess the impact of MRD on PFS amongst patients treated within the non-intensive arm of the NCRI Myeloma XI trial. In this study patients were randomised between thalidomide (CTDa) and lenalidomide (RCDa) based induction therapies with responding patients being subsequently randomised to maintenance with lenalidomide monotherapy, lenalidomide and vorinostat or no further therapy. Bone marrow aspirates were obtained at the end of induction and this analysis represents a subset of 281 patients (median age 74.0 years). MRD was assessed using flow cytometry (sensitivity 10-4) with a minimum of 500,000 cells evaluated with six-colour antibody combinations including CD138/CD38/CD45/CD19 with CD56/CD27 in all cases and CD81/CD117 in additional cases as required. Results: MRD-negativity was demonstrated in 41/ 281 (14.6%) and this was associated with a significant outcome advantage as the median PFS was 34 months versus 19 months for MRD-positive patients (p<0.0001, HR 0.38). Similarly when MRD was assessed as a continuous variable across 5 logs of residual disease there were sequential improvements in outcome with each log reduction. Median PFS for the following disease levels; <0.01%, 0.01 - <0.1%, 0.1% - <1%, 1% - <10% and >10% were 34, 26, 16, 15 and 9 months respectively (p<0.0001, see figure). Multivariate analysis confirmed the in- dependent predictive value of MRD both as a qualitative and continuous quantitative variable (p<0.0001 and p¼0.004 respectively). Conclusions: We would conclude that MRD is a powerful predictor of outcome in transplant ineligible patients and is clearly a desirable therapeutic goal in this patient group. Similar to our previous data in transplant eligible patients there is a significant sequential improvement in outcome with each log depletion. This data further supports the role of MRD as a pri- mary endpoint and surrogate marker for survival in future clinical trials. PO-006 Relationship Between Presence of Osteolytic Lesions, Cytogenetic Features and Bone Marrow Levels of Cytokines and Chemokines in Multiple Myeloma Patients: Role of Chemokine (C-C motif) Ligand 20 as new marker of bone disease B. Dalla Palma, 1,2 D. Guasco, 1 F. Accardi, 1 M. Pedrazzoni, 1,3 M. Bolzoni, 1 F. Costa, 1 G. Sammarelli, 1 L. Craviotto, 1 S. Bonomini, 1 G. Todaro, 1 M. De Filippo, 4 L. Ruffini, 5 F. Aversa, 1,2 N. Giuliani 1,2 1 Department of Clinical and Experimental Medicine, Myeloma Unit, University of Parma, Italy; 2 Hematology and BMT Center, “Azienda Ospedaliero-Universitaria“ Parma, Italy; 3 “Clinica e Terapia Medica” “Azienda Ospedaliero-Universitaria“ Parma, Italy; 4 Radiology Unit, University of Parma, Italy; 5 Nuclear Medicine Unit “Azienda Ospeda- liero-Universitaria“ Parma, Italy The relationship between bone marrow (BM) cytokines and chemokines levels, cytogenetic profiles and the skeletal involve- ment in multiple myeloma (MM) patients is not yet completely defined and has been investigated in this study in a total cohort of Abstracts e84 - 15th International Myeloma Workshop, September 23-26, 2015