Abstract: Bortezomib-melphalan-prednisone (VMP) has improved overall survival in multiple myeloma. This randomized trial compared VMP plus thalidomide (VMPT) induction followed by bortezomib-thalidomide maintenance (VMPT-VT) with VMP in patients with newly diagnosed multiple myeloma. Patients and Methods We randomly assigned 511 patients who were not eligible for transplantation to receive VMPT-VT (nine 5-week cycles of VMPT followed by 2 years of VT maintenance) or VMP (nine 5-week cycles without maintenance). Results In the initial analysis with a median follow-up of 23 months, VMPT-VT improved complete response rate from 24% to 38% and 3-year progression-free-survival (PFS) from 41% to 56% compared with VMP. In this analysis, median follow-up was 54 months. The median PFS was significantly longer with VMPT-VT (35.3 months) than with VMP (24.8 months; hazard ratio [HR], 0.58; P 〈 .001). The time to next therapy was 46.6 months in the VMPT-VT group and 27.8 months in the VMP group (HR, 0.52; P 〈 .001). The 5-year overall survival (OS) was greater with VMPT-VT (61%) than with VMP (51%; HR, 0.70; P = .01). Survival from relapse was identical in both groups (HR, 0.92; P = .63). In the VMPT-VT group, the most frequent grade 3 to 4 adverse events included neutropenia (38%), thrombocytopenia (22%), peripheral neuropathy (11%), and cardiologic events (11%). All of these, except for thrombocytopenia, were significantly more frequent in the VMPT-VT patients. Conclusion Bortezomib and thalidomide significantly improved OS in multiple myeloma patients not eligible for transplantation.

Abstract: Introduction: Risk-adapted therapy in curable hematologic malignancies is commonly applied: low-risk patients (pts) may be cured with less intensive treatment, avoiding excessive toxicity, whereas high-riskpts require more intensive and toxic regimens. In multiple myeloma (MM), this model may not apply, since the disease is incurable. In recent years, there has been a marked improvement in patient outcome, due to the introduction of novel agents and optimized treatment strategies, including the use of transplant and maintenance. A better evaluation ofpts prognosis based on the new revised international staging system (R-ISS) has been also introduced in clinical practice. The objective of this analysis was to evaluate the impact of treatment intensification (specifically autologous stem cell transplantation [ASCT] and maintenance) inpts with different prognostic features. Methods: Data from 3 phase III randomized trials in newly diagnosed MMpts (RV-MM-209; EMN441; GIMEMA-MM0305) were pooled together and analyzed. Baseline patient risk assessment was estimated using R-ISS. We evaluated: 1) the impact of treatment intensification with high-dose therapy followed by ASCTvs no-ASCT inpts with R-ISS Stage Ivs Stage II/III; 2) the impact of treatment intensification with maintenancevs no maintenance inpts with R-ISS Stage Ivs Stage II/III. RV-MM-209 and EMN441 studies randomizedpts to ASCTvs no-ASCT; allpts in the GIMEMA-MM0305 trial did not receive ASCT and were excluded from the first comparison; RV-MM-209 and GIMEMA-MM0305 studies randomizedpts to maintenance or no maintenance after induction/consolidation; allpts in the EMN441 trial received maintenance and were excluded from the second comparison. We evaluated progression free survival-1 (PFS1), PFS2 and overall survival (OS). Cox proportional hazards models were used to estimate hazard ratios (HRs). To account for potential confounders, the comparisons between ASCTvs no-ASCT and maintenancevs no maintenance were adjusted for the trial effect and the main prognostic features. Results: Overall, 1302 pts were enrolled in the 3 trials. Median follow-up was 4 years.Comparison ASCTvs no-ASCT: 791pts were enrolled in the 2 trials, 529 were eligible for the ASCTvs no ASCT comparison. R-ISS Stage data were available for 419 pts. There was an overall advantage for ASCTvs no-ASCT in PFS1 (0.53; p 〈 0.001), PFS2 (HR 0.53; p 〈 0.001) and OS (HR 0.51; p 〈 0.001). The 4-year PFS1 was 53% inpts with R-ISS Stage I randomized to ASCT, 35% inpts with R-ISS Stage II/III randomized to ASCT, 36% inpts with R-ISS Stage I randomized to no-ASCT and 19% in those with R-ISS Stage II/III randomized to no-ASCT (p 〈 0.001); the 4-year PFS2 was 83%, 60%, 71% and 43% in the 4 subgroups, respectively (p 〈 0.001) (Figure 1A, B); the4-year OS was 95%, 75%, 88% and 61%(p 〈 0.001). Comparison maintenancevs no maintenance: 913pts were enrolled in the 2 trials, 550 could be eligible for maintenance. R-ISS data were available in 403 pts. Maintenance significantly improved PFS (HR 0.54, p 〈 0.001), PFS2 (HR 0.52, p 〈 0.001) and OS (HR 0.69, p=0.027) in comparison with no maintenance. The 4-year PFS was 48% forpts with R-ISS Stage-I assigned to maintenance, 37% forpts with R-ISS Stage II/III assigned to maintenance, 25% forpts with R-ISS Stage-I assigned to no maintenance and 18% forpts with R-ISS Stage II/III assigned to no maintenance (p 〈 0.001); the 4-year PFS2 was 73%, 66%, 59% and 43% in the 4 subgroups, respectively (p 〈 0.001) (Figure 1C, D); the 4-year OS was 80%, 73%, 77% and 63% (p 〈 0.001). Conclusions: Both ASCT and maintenance improved PFS1, PFS2 and OS in MM pts. The highest survival was reported in patients with R-ISS Stage I receiving ASCT and/or maintenance. Low-riskpts (R-ISS Stage I) not undergoing intensification with ASCT or maintenance lose their prognostic advantage over high-risk patients receiving the same intensification. Figure 1. Figure 1. Disclosures Gay: Janssen-Cilag: Other: Advisory Board; Celgene: Honoraria; Amgen: Honoraria; BMS: Honoraria; Takeda: Honoraria, Other: Advisory Board; Mundipharma: Other: Advisory Board. Hajek:Novartis: Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Onyx: Consultancy; BMS: Honoraria; Amgen: Consultancy, Honoraria, Research Funding. Bringhen:Mundipharma: Other: Advisory Board; Karyopharm: Other: Advisory Board; BMS: Honoraria; Janssen-Cilag: Honoraria; Amgen: Other: Advisory Board; Celgene: Honoraria. Gaidano:Gilead: Consultancy, Honoraria, Speakers Bureau; Morphosys: Consultancy, Honoraria; Roche: Consultancy, Honoraria, Speakers Bureau; Karyopharm: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria, Speakers Bureau. Caravita:Janssen-Cilag: Honoraria. Cavo:Millennium: Consultancy, Honoraria; Janssen-Cilag: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Foà:Pfizer: Speakers Bureau; Ariad: Speakers Bureau; BMS: Consultancy; Celgene: Consultancy, Speakers Bureau; Amgen: Consultancy, Speakers Bureau; Gilead: Consultancy, Speakers Bureau; Janssen-Cilag: Consultancy, Speakers Bureau; Genetech: Consultancy; Roche: Consultancy, Speakers Bureau. Patriarca:Bristol-Myers Squibb: Other: Advisory board; Mundipharma: Other: Advisory board; Janssen-Cilag: Other: Advisory board; MSD: Consultancy; Celgene: Consultancy. Ria:Italfarmaco: Consultancy, Speakers Bureau; Janssen-Cilag: Other: Advisory Board, Speakers Bureau; CSL Behring: Consultancy, Research Funding, Speakers Bureau; Binding Site: Speakers Bureau; BMS: Speakers Bureau; BMS: Speakers Bureau. Palumbo:Janssen Cilag: Honoraria; Takeda: Employment, Honoraria. Boccadoro:Novartis: Honoraria, Research Funding; Mundipharma: Research Funding; SANOFI: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Abbivie: Honoraria; Amgen: Honoraria, Research Funding; CELGENE: Honoraria, Research Funding; BMS: Honoraria, Research Funding.

Abstract: Abstract 200 Background: In a multicenter phase 3 randomized trial, VMPT-VT was superior to VMP for response rates, progression-free survival and time to next treatment (Palumbo A, et al. J Clin Oncol 2010). Here we report an updated analysis on survival after 4 years of follow-up. Methods: Patients (N=511) were randomly assigned to receive nine 6-week cycles of VMPT-VT (induction: bortezomib 1.3 mg/m2, d 1, 4, 8, 11, 22, 25, 29, 32, cycles 1–4, d 1, 8, 22, 29, cycles 5–9; melphalan 9 mg/m2 d 1–4, prednisone 60 mg/m2, d 1–4, thalidomide 50 mg d 1–42; maintenance: bortezomib 1.3 mg/m2 every 14 days and thalidomide 50 mg/day up to 2 years) or VMP alone. After the inclusion of 139 patients, the protocol was amended: both VMPT-VT and VMP induction schedules were changed to nine 5-week cycles and bortezomib schedule was modified to weekly administration (1.3 mg/m2 d 1,8,15,22, all cycles). Results: After a median follow-up of 47.2 months, median OS was not reached in the VMPT-VT arm and was 58.2 months in the VMP arm; 5-year OS rates were 59.3% and 45.9%, respectively (HR 0.74, p=0.04), with 26% reduced risk of death for patients receiving VMPT-VT (Figure-panel A). This benefit was more evident in patients younger than 75 years (5-year rates 67.8% for VMPT-VT vs 49.9% for VMP, HR 0.63, p=0.01, Figure-panel B) and in patients in complete response (CR) after induction (5-year rates 81.4% for VMPT-VT vs 48.2% for VMP, HR 0.38, p=0.006, Figure-panel C) while no significant differences were evident in patients with standard- or high-risk features detected by FISH (HR 0.99, p=0.99). A 1-year landmark analysis for patients completing induction was performed: the 4-year OS was 64.6% in the VMPT-VT group and 49.7% in the VMP group, with 33% reduced the risk of death for patients receiving VT maintenance (HR 0.67, p=0.02). Forty-nine percent of VMPT-VT and 70% of VMP patients relapsed and received subsequent salvage therapies; there was no difference in survival from relapse in the two groups (2-year OS rates 40.7% vs 50.2%,HR 1.11, p=0.54). The median duration of VT maintenance was 23.8 months. During VT maintenance 7% of patients experienced grade 3–4 peripheral neuropathy, 5% grade 3–4 hematological toxicity, 3% grade 3–4 infection and 12% discontinued due to adverse events. Second primary malignancies were reported in 7/254 patients in the VMPT-VT group and 7/257 patients in the VMP group. These corresponded to incidence rates of 0.9 and 1.05 per 100 patient-years, respectively, and were consistent with background incidence rates in the general population (aged 65–74 years 1.9, aged ≥ 75 years 2.3, SEER database). Conclusions: VMPT-VT significantly prolonged OS compared with VMP, especially in patients younger than 75 years and in patients achieving CR after induction. In patients 67–75 years of age, VMPT-VT reduced the risk of death by 37% and it should be considered a new standard of care. Disclosures: Palumbo: Celgene: Advisory Board, Advisory Board Other, Consultancy, Honoraria; Janssen: Advisory Board Other, Consultancy, Honoraria. Bringhen:Janssen: Honoraria; Celgene: Honoraria. Gentilini:Janssen: Honoraria; Celgene: Honoraria. Patriarca:Janssen: Honoraria. Guglielmelli:Janssen: Honoraria; Celgene: Honoraria. Musto:Janssen: Honoraria, Research Funding; Celgene: Honoraria, Research Funding. Petrucci:Janssen: Honoraria; Celgene: Honoraria. Boccadoro:Janssen: Consultancy, Research Funding, Scientific Advisory Board Other; Celgene: Consultancy, Research Funding, Scientific Advisory Board, Scientific Advisory Board Other.

Abstract: Abstract 128 Background. In newly diagnosed myeloma patients the combination of bortezomib with melphalan-prednisone (VMP) was superior to MP. In relapsed-refractory patients the 4 drug combination bortezomib-melphalan-prednisone-thalidomide (VMPT) induced a high proportion of complete responses (CR). Aims. This prospective, randomized, phase III trial, compared VMPT with a maintenance regimen including bortezomib and thalidomide with VMP without a maintenance regiment. The primary end point was PFS. Methods. Patients (N=511) older than 65 years were randomly assigned to receive VMPT followed by maintenance with bortezomib and thalidomide (N=254) or VMP (N=257). Initially, patients were treated with nine 6-week cycles of VMPT (induction: bortezomib 1.3 mg/m2 days 1,4,8,11,22,25,29,32 in cycles 1–4 and days 1,8,22,29 in cycles 5–9; melphalan 9 mg/m2 days 1–4; prednisone 60 mg/m2 days 1–4 and thalidomide 50 mg days 1–42; maintenance: bortezomib 1.3 mg/m2 every 15 days and thalidomide 50 mg/day) or VMP (bortezomib, melphalan and prednisone at the same doses and schedules previously described without maintenance). In March 2007, the protocol was amended: both VMPT and VMP induction schedules were changed to nine 5-week cycles and bortezomib schedule was modified to weekly administration (1.3 mg/m2 days 1,8,15,22 in cycles 1–9). Results. All patients have been evaluated in intention-to-treat. Patient characteristics were similar in both groups, median age was 71 years. The response rates were always superior in the VMPT group: at least PR rate (86% vs 79%, p=0.02), at least VGPR rate (55% vs 47%, p=0.07) and CR rate (34% vs 21% p=0.0008), respectively. Maintenance treatment did not increase the best response achieved during VMPT induction. After a median follow-up of 17.8 months, the 2-year PFS was 70.0% in the VMPT group and 58.2% in the VMP group (HR=0.62, 95% CI 0.44–0.88, p=0.008). The achievement of CR significantly prolonged PFS in both VMPT (p 〈 0.0001) and VMP (p=0.003) patients. Chromosomal abnormalities, such as del13, t(4;14), t(14;16) or del17, did not affect 2-year PFS in both VMPT (p=0.51) and VMP (p=0.41) patients. The 2-year overall survival (OS) was 89.6% in the VMPT group and 89.0% in the VMP group (HR=0.94, 95% CI 0.51–1.72, p=0.84). The incidence of grade 3–4 neutropenia (37% vs 28%, p=0.02) and cardiac complications (10% vs 5%, p=0.04) was higher in the VMPT group. The incidence of other grade 3–4 adverse events was similar in the VMPT group and in the VMP group: thrombocytopenia (21% vs 19%), peripheral neuropathy (5% vs 8%), infections (12% vs 9%), and gastrointestinal complications (6% vs 8%), respectively. From twice-weekly, the weekly infusion of bortezomib significantly decreased the incidence of grade 3–4 peripheral neuropathy in the VMPT group (from 18% to 4%, p=0.0002) and in the VMP (from 13% to 2%, p=0.0003), without any significant change in CR rates and 2-year PFS. Conclusion. VMPT followed by maintenance with bortezomib and thalidomide was superior to VMP for response rates and PFS. The weekly infusion of bortezomib significantly reduced the incidence of peripheral neuropathy without affecting outcome. This is the first report showing the superiority of a 4-drug combination followed by maintenance in comparison with the most recent standard therapy, VMP. These data will be updated at the meeting. Disclosures: Palumbo: Janssen-Cilag: Honoraria; Celgene: Honoraria. Off Label Use: thalidomide, lenalidomide, bortezomib . Bringhen:Celgene: Honoraria; Janssen Cilag: Honoraria. Patriarca:Janssen Cilag: Honoraria; Celgene: Honoraria. Petrucci:Celgene: Honoraria; Janssen-Cilag: Honoraria. Musto:Janssen Cilag: Honoraria; Celgene: Honoraria. Boccadoro:Celgene: Consultant, advisory committee, Research Funding; Janssen Cilag: Consultant, advisory committee, Research Funding; Pharmion: Consultant, advisory committee, Research Funding.

Abstract: We assessed efficacy, safety, and reversal of renal impairment (RI) in untreated patients with multiple myeloma given bortezomib-melphalan-prednisone-thalidomide followed by bortezomib-thalidomide (VMPT-VT) maintenance or bortezomib-melphalan-prednisone (VMP). Exclusion criteria included serum creatinine ≥ 2.5 mg/dL. In the VMPT-VT/VMP arms, severe RI (estimated glomerular filtration rate [eGFR] ≤ 30 mL/min), moderate RI (eGFR 31-50 mL/min), and normal renal function (eGFR 〉 50 mL/min), were 6%/7.9%, 24.1%/24.9%, and 69.8%/67.2%, respectively. Statistically significant improvements in overall response rates and progression-free survival were observed in VMPT-VT versus VMP arms across renal cohorts, except in severe RI patients. In the VMPT group, severe RI reduced overall survival (OS). RI was reversed in 16/63 (25.4%) patients receiving VMPT-VT versus 31/77 (40.3%) receiving VMP. Multivariate analysis showed male sex (P = .022) and moderate RI (P = .003) significantly predicted RI recovery. VMP patients achieving renal response showed longer OS. In both arms, greater rates of severe hematologic adverse events were associated with RI (eGFR 〈 50 mL/min), however, therapy discontinuation rates were unaffected. VMPT-VT was superior to VMP for cases with normal renal function and moderate RI, whereas VMPT-VT failed to outperform VMP in patients with severe RI, although the relatively low number of cases analyzed preclude drawing definitive conclusions. VMPT-VT had no advantage in terms of RI reversal over VMP. This study is registered at http://www.clinicaltrials.gov as NCT01063179.

Abstract: In patients with myeloma, thalidomide significantly improves outcomes but increases the risk of thromboembolic events. In this randomized, open-label, multicenter trial, we compared aspirin (ASA) or fixed low-dose warfarin (WAR) versus low molecular weight heparin (LMWH) for preventing thromboembolism in patients with myeloma treated with thalidomide-based regimens. Patients and Methods A total of 667 patients with previously untreated myeloma who received thalidomide-containing regimens and had no clinical indication or contraindication for a specific antiplatelet or anticoagulant therapy were randomly assigned to receive ASA (100 mg/d), WAR (1.25 mg/d), or LMWH (enoxaparin 40 mg/d). A composite primary end point included serious thromboembolic events, acute cardiovascular events, or sudden deaths during the first 6 months of treatment. Results Of 659 analyzed patients, 43 (6.5%) had serious thromboembolic events, acute cardiovascular events, or sudden death during the first 6 months (6.4% in the ASA group, 8.2% in the WAR group, and 5.0% in the LMWH group). Compared with LMWH, the absolute differences were +1.3% (95% CI, −3.0% to 5.7%; P = .544) in the ASA group and +3.2% (95% CI, −1.5% to 7.8%; P = .183) in the WAR group. The risk of thromboembolism was 1.38 times higher in patients treated with thalidomide without bortezomib. Three major (0.5%) and 10 minor (1.5%) bleeding episodes were recorded. Conclusion In patients with myeloma treated with thalidomide-based regimens, ASA and WAR showed similar efficacy in reducing serious thromboembolic events, acute cardiovascular events, and sudden deaths compared with LMWH, except in elderly patients where WAR showed less efficacy than LMWH.

Abstract: There are currently no direct head‐to‐head clinical trials evaluating bortezomib‐melphalan‐prednisone (VMP) versus lenalidomide and low‐dose dexamethasone (Rd). VMP (257 cases) and Rd (222 cases) arms of two randomized phase III trials were employed to assess the treatment influence on outcome in untreated elderly MM patients. Progression free survival (PFS) and overall survival (OS) were the primary and secondary end‐points, respectively, and were investigated according to treatments administered over a 60‐months follow‐up period. While VMP significantly reduced the disease progression rate between enrolment and 12 months of follow‐up, no difference between the two schedules was found between 12 and 32 months. After 32 months, Rd‐treated patients had a lower incidence of disease progression. A statistically significant higher OS rate was seen in the VMP arm, which was maintained after data adjustment for potential confounders. Both approaches showed acceptable toxicity profiles. The profound tumor reduction by VMP over Rd justifies the initial higher PFS rate in favor of the bortezomib schedule, while the Rd regimen overcomes this evident initial drawback in reducing the tumor burden by long‐term drug administration, gaining a subsequent improved disease control. VMP is associated with a significant reduced risk of death. This study may help physicians make a more informed therapy choice.

Abstract: Abstract 2925 Primary plasma cell leukemia (PPCL) is an aggressive variant of multiple myeloma, accounting for 0.5–4% of all newly diagnosed myeloma cases and characterized by a short survival (generally less than 1 year), which is only moderately improved by transplant procedures. Novel agents seem to be able to ameliorate the poor clinical outcome of both primary and secondary leukemic phases of myeloma; however, no data are currently available on the use of lenalidomide as first line therapy in PPCL. On March, 2009, we started a multicenter, phase II trial aiming to evaluate safety and antitumor activity of lenalidomide in combination with dexamethasone (LD) in previously untreated PPCL. Here we report the final results of this study. Newly diagnosed PPCL patients received lenalidomide at a dose of 25 mg/d for 21 days and oral dexamethasone at a dose of 40 mg on days 1, 8, 15, and 22 for each 28-day cycle. After 4 cycles, responding patients not eligible for stem cell transplantation (SCT) continued until 8 cycles of full-dose LD, if tolerated, followed by a maintenance dose of single agent lenalidomide equal to 10 mg/d on days 1–21 of each 28-day cycle. Patients responding after 4 cycles and eligible for SCT proceeded according to single Centre transplant policy. Patients not responding after 4 cycles or progressing during this treatment were considered off-study. The primary endpoint was early response rate according to International Uniform Criteria. The secondary endpoints were PFS, OS, safety and percentage of eligible patients able to undergo autologous or allogeneic SCT. Appropriate dose reductions, contraception methods and anti-thrombotic prophylaxis were applied. Twenty-three patients, as requested by the Simon Optimal Two-Stage Adaptive Design adopted, were enrolled. The trial was therefore closed on May, 31, 2011. M/F ratio was 0.7, mean age was 62 years (range 44–80). Circulating plasma cells ranged from 2.1 to 115 × 10e9/l. Moderate renal failure, increased LDH and extramedullary disease occurred in 39.1%, 43.5% and 13 % of patients, respectively. Hb was 〈 10 g/dl in 19 patients (82.6%), while platelet count was 〈 50 × 10e9/l in 5 patients (21.7%). Karyotype abnormalities were detected by FISH in 21 out of 22 tested patients; in particular, 1p loss was found in 9 patients, 1q gain in 10 patients, del(13q) in 16 patients, del(17p13) in 7 patients, t(11;14) in 7 patients, t(4;14) in 3 patients and MAF translocations, including t(14;20) and t(14;16), in 8 patients. Seventeen patients had a combination of two (n. 5) or more (n. 12) cytogenetic lesions. On intention-to-treat analysis, 14 patients completed the initial four planned cycles and all of them responded. In particular, 6 PR (26.1%), 4 VGPR (17.4%), 1 near-CR (4.3%) and 3 CR (13%) were achieved (ORR 60.8%, VGPR or better 34.7%). Causes of early treatment discontinuation were: a) progressive disease (4 patients, after an initial, brief response in 2 cases); b) severe adverse events (4 patients: one acute renal failure, one Stevens-Johnson's syndrome, one pneumonia suspected for Pneumocystis carinii etiology, one multi-organ failure); c) death in PR due to causes unrelated to treatment or disease (one patient). Other relevant non-hematological toxicities included four episodes of pneumonia and one case of DVT. Grade 3–4 hematological toxicities occurred in about half of cases, requiring Lenalidomide dose adjustments. So far, among subjects achieving a response after 4 LD cycles, 8 eligible patients have successfully collected peripheral blood stem cells: 5 of them have completed single or double autologous SCT, one patient received tandem autologous-allogeneic non myeloablative SCT from a MUD donor. All patients transplanted after LD are currently alive and in remission phase. The maintenance phase has been reached in 3 responding patients not eligible for SCT, 2 of whom have relapsed after 2 and 8 months, respectively. With a mean follow-up of 15 months, OS and PFS are 65.2% and 52.1%, respectively. LD is a possible initial therapeutic option for PPCL, particularly in patients who receive SCT after a short course of induction treatment. Caution is required to prevent and to manage renal and hematological toxicities, as well as infectious complications. Considering some previous results obtained with other novel agents, the combination of lenalidomide and bortezomib might be an appealing approach to investigate prospectively in PPCL patients. Disclosures: Musto: Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Petrucci:Celgene: Honoraria. Cascavilla:Celgene: Honoraria. Di Raimondo:Celgene: Honoraria. Caravita:Celgene: Honoraria. Morabito:Celgene: Honoraria. Offidani:Celgene: Honoraria. Bringhen:Celgene: Honoraria. Boccadoro:Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Palumbo:Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.

Abstract: Abstract 3029 Background. In a recent phase 3 trial, bortezomib–melphalan – prednisone–thalidomide followed by maintenance treatment with bortezomib–thalidomide (VMPT-VT) demonstrated superior efficacy compared with VMP. Peripheral neuropathy (PN) was the most important dose limiting toxicity. To decrease neurologic toxicities, the protocol was amended and patients in both arms received once-weekly instead of the initial twice-weekly bortezomib infusions. This post-hoc analysis assessed the impact of bortezomib dose-modification schedule on clinical outcomes and safety. Methods. Patients (N=511) older than 65 years were randomized to receive nine 6-week cycles of VMPT-VT (N=254; induction:V 1.3 mg/m2, d 1, 4, 8, 11, 22, 25, 29, 32, cycles 1–4, d 1, 8, 22, 29, cycles 5–9; M 9 mg/m2 d 1–4, P 60 mg/m2, d 1–4, T 50 mg d 1–42; maintenance: V 1.3 mg/m2 every 14 days and T 50 mg/day) or VMP (N=257) alone. In March 2007, the protocol was amended: both VMPT-VT and VMP induction schedules were changed to nine 5-week cycles and bortezomib schedule was modified to weekly administration (1.3 mg/m2 d 1,8,15,22, all cycles). Patients receiving VMPT-VT and VMP were pooled together and stratified according to the once-weekly or twice-weekly infusion modality; analyses were also conducted for patients receiving VMP only, to eliminate the influence of thalidomide and of maintenance on efficacy and safety. Results. Patients were evaluated in intention-to-treat: 372 patients received once-weekly and 139 twice-weekly bortezomib infusion. Patient characteristics were similar in the two groups, median age was 71 years. The efficacy data did not appear to be affected by the bortezomib schedule. Overall response rates were 85% with once weekly and 86% with twice- weekly schedule (P = .78), including CR rates of 30% and 35% (P = .27).Three-year PFS was 50% in the once-weekly and 47% in the twice-weekly group (P = 1.00), and 3-year OS was 88% and 89%, respectively (P = .54). Similar outcome was seen in the analyses restricted to VMP patients: CR rates were 23% with once-weekly and 27% with twice-weekly schedule (P = .54), 3-years PFS was 46% in once-weekly and 39% (P = .86) in twice-weekly group and 3-years OS was 87% and 89% (P = .47), respectively. The incidence of grade 3/4 hematologic toxicity was similar in the two groups (44% vs 45%, P = .83), but severe thrombocytopenia was slightly less common in the once-weekly patients (19% vs 26%, P = .08).The incidence of non-hematologic grade 3/4 adverse events was significantly reduced in the once-weekly: 35% vs 51% (P = .003). Grade 3/4 gastrointestinal events (6% vs 11%, P = .08), severe systemic events (4% vs 7%, P = .09) and grade 3/4 dermatologic events (2% vs 7%, P = .006) were less frequent in patients receiving once-weekly bortezomib. There was a significantly reduced overall incidence of grade 3/4 PN (8% vs 28%, P 〈 .001) in the once-weekly group. The median time to onset of grade 3/4 sensory PN was 4.3 months in the once-weekly group and 3.2 months in the twice-weekly group (P = .10). The cumulative incidence of sensory PN appeared to plateau after 12 months of therapy in both groups. Rates of discontinuations (5% versus 15%) and dose reductions (15% versus 41%) due to PN were also significantly lower in the once-weekly group (P 〈 .001). These results were reflected in analysis restricted to VMP patients, in which the incidence of grade 3/4 PN (7% vs 29%, P 〈 .001), the discontinuation rate (4% vs 16%, P = 0.002), and the dose reductions rate (15% vs 41% P 〈 0.001) were significantly lower in once-weekly group. Despite the cumulative planned dose being lower in the once-weekly group (46.8 vs 67.6 mg/m2), the delivered cumulative dose of bortezomib was similar in the two groups (39.4 mg/m2 vs 40.1 mg/m2). No association of PN with age or other baseline characteristics was outlined. The only significant factor influencing the incidence of PN was the reduction of bortezomib infusion from twice- to once-weekly (p 〈 0.001). Low dose thalidomide did not affect grade 3/4 PN rate (p=0.16). Conclusion. These results demonstrate that 1. both once-weekly and twice-weekly schedules in combination with MP ± thalidomide are highly effective in patients ≥ 65 years; 2. once-weekly schedule significantly reduced the incidence of PN and decreased the rate of discontinuation, resulting in similar cumulative bortezomib doses in the two groups; 3. the improvement in the safety profile was not associated with any reduction in the efficacy. Disclosures: Bringhen: Celgene: Honoraria; Janssen Cilag: Honoraria. Leoni:Celgene: Honoraria; Janssen Cilag: Honoraria. Patriarca:Celgene: Honoraria; Janssen Cilag: Honoraria; Roche: Honoraria; Merck: Membership on an entity's Board of Directors or advisory committees. Guglielmelli:Celgene: Honoraria; Janssen Cilag: Honoraria. Elice:Celgene: Honoraria; Novatis: Honoraria. Boccadoro:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen-Cilag: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Palumbo:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen-Cilag: Honoraria, Membership on an entity's Board of Directors or advisory committees.