Improved tumor response and survival outcomes with post-transplant bortezomib (Btz) consolidation versus observation (Obs) alone in patients with newly diagnosed multiple myeloma (MM): Results from a randomized, open-label, multicenter, parallel-group phase 2 study

and showed evidence of disease in 145 (93%). After a median follow-up of 3.5 years, the median OS for the entire group was 7 months. Untreated and treated patients had median OS of 2 and 8 months, respectively. At least one previous line of therapy for MM and > 1 cytogenetic abnormality were independently associated with worse OS. The median OS for patients with 0, 1 and 2 of these risk factors were 25 months, 5.5 months and 2 months, respectively. Conclusion: Neurological manifestations observed in patients with MM should raise a suspicion of CNS involvement. The diagnosis of CNS MM should be based on imaging studies and CSF cytology and flow cytometry. Although prognosis is generally poor, especially in patients with a long history of chemotherapy and unfavorable cytogenetic profile, survival of individuals free from these negative prognostic factors can be prolonged due to administration of systemic treatment and/or radiotherapy. Prospective multi-institutional studies are warranted to improve the outcome of patients with CNS MM. PO-089 Improved tumor response and survival outcomes with post-transplant bortezomib (Btz) consolidation versus observation (Obs) alone in patients with newly diagnosed multiple myeloma (MM): Results from a randomized, open-label, multicenter, parallel-group phase 2 study O. Sezer, E. Terpos, R. Hajek, G. Sucak, S. Cagirgan, W. Linkesch, O.M. Akay, G. Armbrecht, T. Plesner, J.A. Snowden, H. Nahi, Z. Gulbas, A. Potamianou, C. Couturier, R. Olie, C. Feys, N. Allietta, M. Beksac Department of Hematology and Stem Cell Transplantation, Memorial Hospital, Istanbul, Turkey; Department of Clinical Therapeutics, University of Athens School of Medicine, Alexandra General Hospital, Athens, Greece; Internal Medicine and Hematooncology, Masaryk University Hospital Brno and Faculty of Medicine University Hospital Ostrava, Czech Republic; Department of Hematology, Faculty of Medicine, Gazi University, Ankara, Turkey; Department of Hematology and BMT Center, Izmir Medicalpark Private Hospital, Izmir, Turkey; Department of Hematology, Medical University Clinic, Medical University of Graz, Graz, Austria; Hematology Department, Eskisehir Osmangazi University, Eskisehir, Turkey; Centre for Muscle and Bone Research, Charite e Campus Benjamin Franklin, Berlin, Germany; Department of Hematology, Vejle Hospital, Vejle and IRS/ SDU, Denmark; Department of Haematology, Royal Hallamshire Hospital, Sheffield, UK; Haematology Centre, Karolinska University Hospital, Stockholm, Sweden; Bone Marrow Transplantation Department, Anadolu Health Center, Kocaeli, Turkey; Janssen-Cilag Pharmaceutical SACI, Athens, Greece; Janssen-Cilag, Issy-lesMoulineaux, France; Janssen-Cilag AG, Zug, Switzerland; Janssen Research & Development, Division of Janssen Pharmaceutica NV, Beerse, Belgium; Covance for Janssen-Cilag, Issy-les-Moulineaux, France; Department of Hematology, Ankara University, Ankara, Turkey Background: Induction therapy followed by high-dose chemotherapy and autologous stem cell transplantation (ASCT) is a standard frontline treatment for eligible MM patients (pts). PostASCT consolidation can improve depth of response and long-term outcomes. This phase 2 study evaluated the effects of Btz consolidation vs Obs alone on MM-related bone disease; pre-specified secondary endpoints of disease status (myeloma response), PFS, and OS are reported here. Methods: Eligible pts were adults with newly diagnosed MM who had achieved PR after single/double ASCT. Pts were randomized 1:1 (stratified by baseline bisphosphonate use and age) to receive 4 x 35-d cycles of Btz 1.6 mg/m2 IV on d 1, 8, 15, and 22, or Obs alone, followed by 18-mos’ follow-up for disease status and survival monitoring. Response was investigator-assessed per IMWG 2009 criteria. A last observation carried forward approach was used for missing assessments. PFS and OS were estimated using Kaplan-Meier analysis; exploratory p-values were determined using the log-rank test. Results: Between July 2009 and May 2012, 106 pts were randomized (52 Btz, 54 Obs). 2 pts were withdrawn prior to d 1, thus the modified intent-to-treat (mITT) population included 104 pts (51 Btz, 53 Obs): median age 58 vs 57 yrs; 71% vs 66% prior Btz-based induction. 41 (79%) and 46 (85%) pts completed the respective Btz consolidation and Obs phases as planned. CR+sCR rates at screening were 16% (Btz) and 15% (Obs). After the treatment/Obs phase, response rates were (Btz vs Obs): CR+sCR 22% vs 11%; VGPR 80% vs 68%; PD 8% vs 23%. PFS appeared longer with Btz consolidation vs Obs, both from randomization (median 44.9 vs 21.8 mos) and from first antiMM treatment (median 50.7 vs 35.0 mos) (Figure). After 21 (20%) deaths (11 Btz; 10 Obs), mean OS from randomization was 40.1 vs 36.6 mos and from first anti-MM treatment was 51.7 vs 47.1 mos; median OS was not reached in either arm at both time points. Pvalues for between-arm differences in response rates, PFS, and OS were all >0.05, likely due to small sample size. Conclusion: Compared with Obs alone, Btz consolidation was associated with trends for improved response depth and longer PFS and OS in newly diagnosed MM pts. Our response and PFS findings compare favorably with recent phase 3 data of Btz consolidation vs Obs in 15th International Myeloma Workshop, September 23-26, 2015 e129