Abstract: Deep clonal responses improve outcomes and can change the natural history of advanced (cardiac stage III) AL amyloidosis. NT-proBNP 〉 8500 ng/L and SBP 〈 100 mm Hg identify a very poor risk subgroup of stage III AL amyloidosis.

Abstract: Abstract 995 N-terminal fragment of BNP (NT-proBNP) and cardiac troponin –T (TnT) or I (TnI) form a useful staging system in AL amyloidosis and poor outcomes have been reported in stage III patients treated before routine use of novel agents. These patients are routinely excluded from clinical trials and prospective outcome data is limited but recent studies suggest that some such patients may have better outcomes. We report the outcomes of 347 patients with Mayo stage III AL amyloidosis seen at the amyloid centres in London (UK), Pavia (Italy), Heidelberg (Germany) and Athens (Greece). Organ involvement and responses are defined according to 2005 amyloidosis consensus criteria. Presenting features were [n (%)/median (range)]: cardiac, renal and liver involvement in 338 (97%), 216 (62%) and 77 (22%) respectively, NT-proBNP 9106 ng/L (379–216187); TnI – 0.18 ng/ml (0.1–12); TnT −0.09 ng/ml (0.04–8.2) and IVS 15 mm (7–24). Treatments given were: Bortezomib combinations - 23 (7%), MDex - 150 (43%), thalidomide combinations - 96 (28%), lenalidomide combinations - 13 (4%). 30 (8%) were deemed too ill for treatment or died prior to treatment initiation. Only 37% completed the planned treatment course. The haematological responses on an intention to treat basis were seen in (Overall response rate/complete response (CR)/partial response (PR))(n(%)): MDex – 63(42%)/24 (16%)/39 (26%); Thalidomide combinations 31(32%)/11(12%)/20(21%), bortezomib combinations 10(43%)/6 (23%)/4 (17%), lenalidomide combination 5(38%)/0(0%)/5(38%). The median overall survival (OS) was 7.1 mos. The overall survival at 12 months from response evaluation was 74% for CR, 52% for PR and 18% for NR and from diagnosis was (median): CR – 59 mo, PR 28 mo, NR 10 mo and not assessable for response 2.9 mos. Stage III patients without echocardiographic evidence of cardiac involvement had excellent outcomes with 80% estimated 2 year OS. Using best fit cut-off, in multivariate model (including NT-proBNP., systolic blood pressure (SBP), ejection fraction, NYHA, ECOG, dFLC, LV wall thickness), NT-proBNP 〉 8000 ng/L (HR 2.3; p 〈 0.0001) and SBP 〈 100 mm of Hg (HR 1.6; p 〈 0.0001) were the only independent predictors of poor outcome. Using NT-proBNP 〉 8000 ng/L and SPB 〈 100 mm of Hg as high risk criteria, stage III patients can be further subdivided based on presence of none, one or two criteria with OS of 25 mo, 6 mo and 3 mo respectively. Using these criteria, on intent to treat basis, OS by CR/PR/NR was: no high risk factors – median not reached/69 mo/7 mo and one high risk factor - 59 mo/23 mo/4 mos respectively and too few patients for patients with two high risk factors making comparison unreliable. In conclusion, outcomes amyloidosis patients with stage III disease remain poor. However, stage III patients are heterogeneous and combination of NT-proBNP and SBP can usefully sub-classify these patients. Patients with abnormal biomarkers just due to renal failure in absence of cardiac involvement should be excluded from the current Mayo staging system. Although, treatment responses of stage III patients, on intent to treat basis, are poor with all regimes, it is encouraging that haematological responses improve outcomes and patients who achieve a CR have best outcomes. Clinical trials are urgently needed in patients with stage III disease to confirm these findings and define optimal treatment options. Disclosures: No relevant conflicts of interest to declare.

Abstract: Abstract 1364 In light chain (AL) amyloidosis, as well as in multiple myeloma, response to treatment is increasingly being used as a surrogate endpoint in clinical trials. In 2005 a consensus statement of the International Society of Amyloidosis (ISA) established the criteria for hematologic and organ response. Since then, several studies emphasized the prognostic relevance of the measurement of the amyloidogenic precursor, the circulating free light chain (FLC). Moreover, it was reported that patients who with treatment achieved decreases in the cardiac biomarker N terminal natriuretic peptide type B (NT-proBNP) had longer survival, although echocardiographic criteria of response were not attained. The ISA Consensus Panel reconvened in 2010 to update hematologic and organ response criteria. The panel felt that any new criteria should be validated in a large patient population. Thus, we systematically gathered from 7 referral centers in Europe and in the United States a cohort of 649 patients with systemic AL amyloidosis who had been evaluated for hematologic and organ responses at diagnosis and 6 months after treatment initiation, excluding patients who died earlier. At diagnosis, 430 patients (66%) had heart involvement, 377 (58%) had NT-proBNP ≥650 ng/L, 455 (70%) had renal involvement (95, 15%, with glomerular filtration rate 〈 30 mL/min) and 100 (15%) had liver involvement. Two-hundred eighty-nine patients (44%) were treated with melphalan and dexamethasone, 118 (18%) received thalidomide based therapy, 73 (11%) underwent autologous stem cell transplant, 35 (5%) were treated with regimens including lenalidomide, 20 (3%) received bortezomib-based therapy, and the rest received other alkylating agents, nucleoside analogues or dexamethasone. The median follow-up of living patients was 24 months, and 233 patients (34%) died. The ability of response criteria to identify patients who died was compared by evaluating the areas under Receiver Operator Characteristic curves based on death at 1 year, and by calculating the Harrell C statistic and the Royston explained variation. Survival was calculated from the time of evaluation of response. We maintained the category of complete response (CR: negative serum and urine immunofixation, normal FLC kappa/lambda ratio and normal marrow studies) and examined candidate criteria for partial (PR) and very good partial responses (VGPR), based on percentage changes or absolute values achieved after treatment of involved (amyloidogenic) FLC (iFLC), and alternatively on the difference between iFLC and uninvolved FLC (dFLC). With respect to cardiac response and progression, NT-proBNP-based criteria were defined as a decrease or an increase of both 〉 30% and 〉 300 ng/L, and a threshold of evaluability based on NT-proBNP baseline level 〉 650 ng/L was chosen. The most powerful criteria for PR were those based on dFLC percent decrease, and a 50% cutoff was preferred because of easier clinical use. Among candidate criteria for VGPR, the best were based on iFLC absolute value achieved after therapy, but the performance of those based on dFLC absolute value was only slightly lower. Therefore, a definition of VGPR based on dFLC ( 〈 40 mg/L) was adopted for the sake of harmonization with the dFLC-based definition of PR. The adopted hematologic response criteria and their prognostic significance are reported in Table 1. These criteria identified 4 groups with significantly different survivals (Figure 1). Also the proposed criteria of NT-proBNP response and progression were significantly associated with survival (Figure 2). Our 2010 revised consensus criteria for hematologic response include maintenance of the definition of CR, and with use of dFLC re-casting the definition of PR and introducing a VGPR category, and for cardiac response and progression introducing the use of changes in NT-proBNP levels. In a further analysis we will address the definition of measurable dFLC at baseline and evaluate the applicability of the response criteria to earlier evaluation of response. The revised criteria improve the framework for clinical research in AL. Disclosures: Off Label Use: Thalidomide, lenalidomide, bortezomib for systemic AL amyloidosis. Dispenzieri:The Binding Site: Honoraria. Gertz:Celgene: Honoraria; Millennium: Honoraria, Membership on an entity's Board of Directors or advisory committees. Dimopoulos:Ortho-Biotech: Honoraria; Celgene: Honoraria; Millennium: Honoraria. Merlini:Millennium: Honoraria; Ortho-Biotech: Honoraria.

Abstract: Abstract 731 Background: Treatment with bortezomib achieves high hematologic response rates and rapid and durable responses in AL patients (pts), providing the rationale for proteasome inhibition in this population. MLN9708 is an investigational, oral, potent, reversible, and specific 20S proteasome inhibitor (PI). In preclinical studies, MLN9708 has shown improved antitumor activity compared to bortezomib in a range of xenograft models. This phase 1 study (NCT01318902) assessed weekly doses of oral MLN9708 in pts with relapsed or refractory AL. Methods: Pts aged ≥18 years with relapsed or refractory AL after ≥1 prior therapy, cardiac biomarker stage I/II disease, and measurable major organ (heart/kidney) involvement, received increasing doses of oral MLN9708 (standard 3+3 dose escalation fixed doses of 4.0 and 5.5 mg), on days 1, 8, and 15 of 28-day cycles for up to 12 cycles. Pts with no major hematologic response ( 〈 PR) after 3 cycles received dexamethasone (dex; 40 mg, days 1–4). Two expansion cohorts of PI-naïve and PI-exposed pts were enrolled at the MTD. The primary objectives were to determine the safety, tolerability, and MTD. Secondary objectives included analysis of plasma pharmacokinetic (PK) and whole blood pharmacodynamic effects of MLN9708, and assessment of overall hematologic response rate, time to and duration of hematologic and organ response. Adverse events (AEs) were graded using NCI-CTCAE version 4.03. Blood samples were collected at multiple timepoints pre- and post-MLN9708 dosing for PK analysis during cycle 1. Hematologic response and amyloid-related organ assessments were performed according to standardized criteria. Results: At data cut-off (June 29, 2012) 16 pts had been enrolled and received ≥1 MLN9708 dose (safety population). The median age was 66.5 years (range 54–78) and 7 were male. Median number of prior therapies was 3 (range 1–7); 10 received prior transplant, 7 received prior bortezomib. Major organ involvement, defined by standard criteria, included heart, kidney, or both in 7/5/4 pts, respectively, with a median of 2 (range 1–5) involved organ systems, and Mayo cardiac biomarker risk stage was I, II, III in 6, 9, 1 pts. Five pts were treated in the 5.5 mg cohort and 11 pts were treated in the 4.0 mg (n=6 dose escalation; n=5 dose expansion) cohorts. Of the 11 pts treated at 4.0 mg, 4 were PI-naïve, 7 were PI-exposed. Pts received a median of 3 cycles (range 1–12); 5 pts received ≥5 cycles, and 8 pts remain on treatment. Dex was added in 4 pts (2 in each MLN9708 dose level). There were no on-study deaths. Pts discontinued due to disease progression (n=5), AE, withdrawal by pt, or unsatisfactory response (each n=1); 2 pts completed planned 1 year of therapy. One pt in the 4.0 mg cohort experienced a DLT of grade 3 thrombocytopenia. Two pts in the 5.5 mg dose cohort experienced DLTs: grade 3 diarrhea in 1 pt, and renal failure, respiratory failure (both grade 2), and cardiac arrest (grade 4) in another pt. The MTD was determined as 4.0 mg. AEs were reported in 14 pts. The most common drug-related AEs included nausea (n=5), diarrhea and thrombocytopenia (each n=4), abdominal pain and fatigue (each n=3). Grade ≥3 AEs (any cause) reported in 〉 1 pt were thrombocytopenia (n=4), dyspnea (n=3), maculo-papular rash, dehydration, and abdominal pain (each n=2); all were grade 3. Preliminary response data are shown in the table. At data cut-off, one responder had progressed, and the median duration of hematologic response was 7.4 months (range 1.3–11.5+); 2 pts had cardiac organ response. Preliminary PK data showed that MLN9708 was rapidly absorbed, with a median Tmax of 1 hr (range 0.5–6). MLN9708 day 15 plasma Cmax was 73.6 ± 40.2 ng/mL (mean ± SD) and AUC0–168was 1250 ±530 ng*hr/mL (n=8 at 4.0 mg dose cohort). MLN9708 PK parameter values in this study appear similar to other MLN9708 studies in myeloma pts. Conclusions: These data suggest weekly oral administration of MLN9708 is feasible in pts with relapsed or refractory AL. The MLN9708 MTD was determined as 4.0 mg. Assessment is ongoing, with preliminary evidence of hematologic responses noted. A phase 3 study of MLN9708 plus dex versus physician's choice of treatment is planned (NCT01659658). Disclosures: Merlini: Millennium Pharmaceuticals, Inc.: Consultancy. Off Label Use: Use of the investigational agent MLN9708, an oral proteasome inhibitor, in the treatment of relapsed or refractory light-chain amyloidosis. Sanchorawala:Celgene: Research Funding; Millennium Pharmaceuticals, Inc.: Research Funding; Onyx: Research Funding. Zonder:Celgene: Research Funding; Millennium Pharmaceuticals, Inc: Consultancy, Research Funding. Kukreti:Roche: Consultancy, Honoraria; Celgene: Honoraria; Janssen: Honoraria. Schonland:Celgene: Honoraria, Research Funding; Janssen: Honoraria. Dispenzieri:Janssen Research & Development: Research Funding; Millennium Pharmaceuticals, Inc.: Research Funding; Celgene: Research Funding. Cohen:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Meyers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Onyx: Honoraria, Membership on an entity's Board of Directors or advisory committees. Berg:Millennium Pharmaceuticals, Inc.: Employment. Liu:Millennium Pharmaceuticals, Inc.: Employment. Di Bacco:Millennium Pharmaceuticals, Inc.: Employment. Gupta:Millennium Pharmaceuticals, Inc.: Employment. Hui:Millennium Pharmaceuticals, Inc.: Employment. Comenzo:Millennium Pharmaceuticals, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding.

Abstract: Abstract 4057 Combinations of older drugs and novel agents are constantly improving the outcome of chemotherapy in AL amyloidosis. Bendamustine has demonstrated activity in multiple myeloma and Waldenström macroglobulinemia. In the present study we evaluated the safety and efficacy of Bendamustine and prednisone (BeP) in 36 patients with AL amyloidosis from two European referral centers, the Amyloidosis Center (Heidelberg, Germany) and the Amyloidosis Research and Treatment Center (Pavia, Italy). The databases of the two centers were systematically searched for patients with AL amyloidosis treated with BeP. Nineteen patients were treated in Heidelberg and 17 in Pavia. The patients received 28-day cycles of bendamustine (60–100 mg/m2 on days 1 and 2) and prednisone (100 mg on days 1–4). The target dose of bendamustine was 100 mg/m2, and lower doses were used in 20 patients (55%) who had baseline cytopenia. Ten patients (28%) had IgM clones. Of them, 8 received rituximab associated with BeP. Response was evaluated according to the novel criteria of the International Society of Amyloidosis. Patients' characteristics are reported in Table 1. Severe (grade 3 or 4) adverse events (SAE) were observed in 33% of subjects, most common being cytopenia (17%). Other SAEs were fever (6%), portal vein thrombosis, skin rash, renal failure, and weight loss, in 1 patient each. By intention to treat, 17 patients (47%) achieved hematologic response, with complete remission (CR) in 1 case (3%), and very good partial response in 2 (6%). The median time to response was 3 months. The dose of bendamustine administered in each cycle was not associated with response. Three out of 5 treatment-naïve patients responded. Interestingly, amongst the 8 subjects with IgM clones receiving BeP combined with rituximab, 6 (75%) responded (1 CR), including 1 out of 3 subjects who were refractory to previous rituximab. Amongst 10 patients who were refractory to melphalan, bortezomib and lenalidomide, 4 responded to BeP. Cardiac responses were observed in 3 patients (12%), two of whom also had liver response and one improvement of peripheral neuropathy. Overall, 12 patients (33%) died, and 65% of patients are alive after 3 years. Two subjects died within 3 months from treatment initiation due to advanced cardiac amyloidosis. A troponin I concentration 〉 0.1 ng/mL or a high-sensitivity troponin T level 〉 77 ng/L negatively affected survival (median 5 vs. 45 months, P=0.003). In a 3-month landmark analysis, response to BeP conferred a significant survival advantage (Figure 1). Treatment with bendamustine is effective and well tolerated, representing an additional treatment option in AL amyloidosis, particularly as salvage therapy. Its use in combination with rituximab in IgM patients is very promising, and warrants further studies in prospective international trials. Table 1. Patients' characteristics Variable N (%)/median (range) Newly diagnosed 5 (14) Refractory to previous therapy 24 (67) Relapsed after previous therapy 7 (19) Number of prior therapies 2 (0–5) Previous treatment type: alkylating agents 29 (81) bortezomib 16 (44) lenalidomide 12 (33) thalidomide 6 (17) rituximab* 6 (17) Male gender 18 (50) Age, years 66 (33–80) Organ involvement heart 25 (69) kidney 20 (56) soft tissues 13 (36) liver 10 (28) peripheral nervous system 8 (22) Two or more organs involved 22 (61) New York Heart association class III or IV 14 (39) Cardiac Stage° I 9 (28) II 19 (59) III 4 (13) Estimated glomerular filtration rate 22 (61) ≥60 mL/min per 1.73 m2 11 (31) 30–59 mL/min per 1.73 m2 3 (8) 〈 30 mL/min per 1.73 m2 Bone marrow infiltration 15 (3–30) * Used in patients with IgM clones. °Available in 32 patients. Cardiac staging was based on N-terminal pro-natriuretic peptide type-B (cutoff 332 ng/L) and cardiac troponin I (cutoff 0.1 ng/mL) or high-sensitivity troponin T (cutoff 77 ng/L). Stage I patients had both markers below the cutoffs, stage II only one marker above the cutoffs and stage III patients both markers above the cutoffs. Figure 1. Survival according to response to therapy Figure 1. Survival according to response to therapy Disclosures: Off Label Use: Use of bendamustine in AL amyloidosis.