Citations

Abstract Background: MASS-FIX is a novel method for detection, characterization and quantification of serum and urine monoclonal proteins in multiple myeloma (MM) which uses immunoglobulin enrichment coupled with matrix-assisted laser desorption ionization time-of-flight mass-spectrometry (MALDI-TOF). MASS-FIX has been endorsed by the International Myeloma Working Group (IMWG) as an alternative to immunofixation electrophoresis for diagnosis and disease monitoring in MM and has replaced immunofixation electrophoresis in our institution. This technique has demonstrated superior sensitivity and specificity compared to conventional gel-based methods, but its prognostic value is still unknown. We designed this study to evaluate whether serum M protein monitoring by MASS-FIX has prognostic significance in predicting disease progression in patients with MM. Methods: In the first part of the study, we included patients with MM who had a documented negative MASSFIX after first-line treatment and had serial MASS-FIX data available (n=187). We then compared the time to next treatment (TTNT) between patients who became positive by MASS-FIX and those who remained negative by last follow up. In the second part, we included patients who were positive by MASS-FIX within 90 days from diagnosis and had available serial MASS-FIX data (n=203). We compared TTNT between patients who became negative by MASS-FIX and those who remained positive by last follow up. TTNT was defined as the time of initiation of the first-line treatment to the time of initiation of second-line treatment or last follow up. Results: Part 1: We included 155 patients diagnosed with MM between January 2013 and December 2019 who had a documented negative MASSFIX with first-line treatment and had serial MASSFIX data available. After a median follow up of 3.1 (95%CI: 2.6-3.5) years, 44 (28%) patients became MASSFIX positive, while 111 (72%) still had negative MASS-FIX. The median time from treatment start to negative MASSFIX was 18.0 (IQR: 6.4-33.5) months. The median TTNT was 4.1 (95%CI: 3.2 - NR) years in patients who became MASSFIX positive and not reached (NR) (95%CI: NR-NR) in patients who were MASS-FIX negative by last follow up (P<0.001). The 2-year OS was 97% and 100% in the 2 groups, respectively (P=0.27). Part 2: We included 203 patients who had positive MASSFIX within 90 days from diagnosis and available serial MASSFIX data. The median follow-up was 1.5 (95%CI: 1.5-1.7) years. By last follow up, 39 (19%) patients became MASSFIX negative while 164 (81%) still had positive MASSFIX. The median TTNT was NR (95%CI: 2.0-NR) years in patients who developed negative MASSFIX and 2.3 (95%CI: 1.9 - NR) years in patients who were still MASS-FIX positive by last follow up (P=0.03). The 2-year OS was 97% and 94% in the 2 groups, respectively (P=0.84) Conclusion: The utilization of MASS-FIX in disease monitoring of MM patients provides prognostic information; among patients who become MASS-FIX negative after first line treatment, an earlier conversion to positive MASS-FIX predicts disease progression. Similarly, persistent MASS-FIX positivity after treatment initiation predicts earlier disease progression. Larger studies and longer follow up are needed to evaluate whether the MASS-FIX is associated with overall survival. Disclosures Murray: Mayo Clinic: Other: Has received patents for the Mass-Fix technology which has been licensed to the Binding Site with potential royalties.. Dispenzieri: Sorrento Therapeutics: Consultancy; Oncopeptides: Consultancy; Pfizer: Research Funding; Alnylam: Research Funding; Takeda: Research Funding; Janssen: Consultancy, Research Funding. Kapoor: Karyopharm: Consultancy; Cellectar: Consultancy; BeiGene: Consultancy; Pharmacyclics: Consultancy; Sanofi: Consultancy; Amgen: Research Funding; Ichnos Sciences: Research Funding; Regeneron Pharmaceuticals: Research Funding; Glaxo SmithKline: Research Funding; Karyopharm: Research Funding; Sanofi: Research Funding; Takeda: Research Funding; AbbVie: Research Funding. Gertz: Akcea Therapeutics, Alnylam Pharmaceuticals Inc, Prothena: Consultancy; Akcea Therapeutics, Ambry Genetics, Amgen Inc, Celgene Corporation, Janssen Biotech Inc, Karyopharm Therapeutics, Pfizer Inc (to Institution), Sanofi Genzyme: Honoraria; Ionis Pharmaceuticals: Other: Advisory Board; Aurora Biopharma: Other: Stock option; AbbVie Inc, Celgene Corporation: Other: Data Safetly & Monitoring. Dingli: Sanofi: Consultancy; GSK: Consultancy; Novartis: Research Funding; Apellis: Consultancy; Janssen: Consultancy; Alexion: Consultancy. Kumar: Amgen: Consultancy, Research Funding; Bluebird Bio: Consultancy; Antengene: Consultancy, Honoraria; BMS: Consultancy, Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Beigene: Consultancy; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche-Genentech: Consultancy, Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Carsgen: Research Funding; Merck: Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncopeptides: Consultancy; Novartis: Research Funding; Tenebio: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding.

Abstract Introduction: A baseline involved to uninvolved free light chain ratio (FLCr) ≥100 with involved free light chain (iFLC) ≥10 mg/dL is considered a multiple myeloma (MM)-defining event (MDE). However, prior reports have demonstrated that the presence of multimeric light chain aggregates can contribute to falsely increased FLC levels due to impaired renal light chain clearance. Therefore, we aimed to compare the disease progression risk in patients with high versus low urine monoclonal protein (uMCP) excretion in the setting of an elevated serum FLCr. Methods: We retrospectively evaluated untreated smoldering MM (SMM) and asymptomatic MM patients diagnosed between January 1, 2000 and January 10, 2020. Included patients had a baseline bone marrow plasma cell (BMPC) burden of 10-59% without concomitant end organ damage (hypercalcemia, anemia, renal failure, or lytic lesions on x-ray or cross-sectional imaging; "CRAB" MDE). Patients with a baseline FLCr ≥100 and iFLC >10 mg/dL were included if they had a 24-hour urine collection and electrophoresis. Survival analyses were performed using the Kaplan-Meier method. Progression was defined as treatment for systemic AL amyloidosis or symptomatic MM (typical "CRAB" MDE). SMM patients treated due to evolving biomarkers or "SLiM" MDE (lytic lesions on MRI, BMPC ≥60%, or FLCr ≥100) were censored. Cox proportional hazards models were used for uni- and multivariable analyses. A two-sided p-value <0.05 was considered statistically significant. Results: We included 822 patients without MDE besides elevated FLCr (n=120 with FLCr ≥100, n=702 with FLC <100). Patients with a FLC ≥100 were grouped based on 24-hour uMCP excretion (≥200 mg/24h [n=35], <200 mg/24h [n=85]). Among included patients with a baseline FLCr ≥100, the median iFLC was 79.9 (IQR 42.9-131.5) mg/dL and median FLCr was 207.1 (IQR 137.7-400.3). Patients with a FLCr ≥100 and high (≥200 mg/24h) versus low (<200 mg/24h) uMCP excretion had a median iFLC of 101 versus 66.5 mg/dL (p=0.001), median estimated glomerular filtration rate (eGFR) 74.4 versus 74.6 mL/min/1.73m 2 (p=0.505), and median BMPC burden of 30% versus 21% (p=0.088), as shown in Table 1. The 2-year risk of progression to symptomatic MM or AL amyloidosis was significantly higher in patients with uMCP excretion ≥200 versus <200 mg/24h (36.2% versus 13.5%, respectively; HR 2.79, 95% CI 1.57-4.96, p<0.001, see Figure 1). However, the progression risk was similar in patients with a baseline FLCr <100 versus those with a FLCr≥100 and uMCP <200 mg/24h (log rank p=0.127). After adjusting for baseline eGFR, BMPC burden, iFLC, and light chain isotype, the progression risk was still 2.7 times higher in patients with high versus low uMCP excretion (HR 2.66, 95% CI 1.39-5.10, p=0.003). In patients with a baseline FLCr ≥100 that had cross-sectional imaging at diagnosis or prior to progression confirming the absence of osteolytic lesions, the risk of progression remained significantly higher in patients with a high versus low uMCP excretion (n=14 versus n=53, respectively; HR 4.20, 95% CI 1.86-9.49, p<0.001). In patients with FLCr ≥100, there were a total of 52 patients with end organ damage at progression (26 [50%] patients with anemia, 8 [15%] with renal failure, 21 [40%] with lytic lesions, 6 [12%] with systemic AL amyloidosis). Among patients who progressed, 5 (25%) of 20 patients with high uMCP excretion and 3 (9.4%) of 32 patients with low uMCP excretion presented with renal failure as the MDE. In patients with baseline high versus low uMCP excretion that experienced renal failure at progression, the median serum creatinine of 2.7 (range 1.9-4.1) versus 2.5 (range 1.9-3.2) mg/dL (p=0.653), median uMCP 4964 (range 738-5910) versus 512 (range 196-734) mg/24h (p=0.052), and median iFLC 388 (range 317-1640) versus 437 (range 199-1030) mg/dL (p=1.00). Conclusions: Increased uMCP excretion in the setting of a FLCr ≥100 is an unfavourable prognostic marker and is associated with an increased risk of progression. The progression risk in patients with a FLCr ≥100 and low uMCP excretion (<200 mg/24h) is similar to patients with a baseline FLCr <100. Our findings underscore the importance of conducting a 24-hour urine assessment at diagnosis and may help refine the subset of patients with FLCr ≥100 in whom pre-emptive therapy is warranted. Figure 1 Figure 1. Disclosures Kapoor: AbbVie: Research Funding; Takeda: Research Funding; Sanofi: Research Funding; Karyopharm: Research Funding; Glaxo SmithKline: Research Funding; Regeneron Pharmaceuticals: Research Funding; Ichnos Sciences: Research Funding; Amgen: Research Funding; Karyopharm: Consultancy; Cellectar: Consultancy; BeiGene: Consultancy; Pharmacyclics: Consultancy; Sanofi: Consultancy. Gertz: Akcea Therapeutics, Ambry Genetics, Amgen Inc, Celgene Corporation, Janssen Biotech Inc, Karyopharm Therapeutics, Pfizer Inc (to Institution), Sanofi Genzyme: Honoraria; Aurora Biopharma: Other: Stock option; Akcea Therapeutics, Alnylam Pharmaceuticals Inc, Prothena: Consultancy; AbbVie Inc, Celgene Corporation: Other: Data Safetly & Monitoring; Ionis Pharmaceuticals: Other: Advisory Board. Dingli: Novartis: Research Funding; GSK: Consultancy; Alexion: Consultancy; Sanofi: Consultancy; Janssen: Consultancy; Apellis: Consultancy. Kumar: Antengene: Consultancy, Honoraria; Bluebird Bio: Consultancy; Roche-Genentech: Consultancy, Research Funding; Novartis: Research Funding; Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Research Funding; Carsgen: Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Research Funding; Oncopeptides: Consultancy; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Beigene: Consultancy; Tenebio: Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding.

Abstract Introduction: Light chain (AL) amyloidosis is a plasma cell disease characterized by the deposition of insoluble amyloid fibrils into organs leading to organ dysfunction and death. The analysis at 6 and 12 months of the ANDROMEDA study (NCT03201965) showed that the addition of subcutaneous (SC) daratumumab to the standard of care combination of bortezomib, cyclophosphamide, and dexamethasone (VCd) was superior to VCd alone, with higher rates of hematologic complete response (CR) and an acceptable safety profile. Based on these findings daratumumab with VCd (D-VCd) was approved for newly diagnosed AL amyloidosis in January 2021 in the US and June 2021 in the EU. Here, we present data from the analysis at 18 months of the ANDROMEDA study. Methods: ANDROMEDA is a randomized, open-label, active-controlled phase 3 study including patients with newly diagnosed AL amyloidosis with measurable hematologic disease, ≥1 involved organ, cardiac stage I-IIIA, estimated glomerular filtration rate ≥20 mL/min, and absence of symptomatic multiple myeloma. Patients were randomized (1:1) to D-VCd or VCd for 6 28-day cycles. Bortezomib (1.3 mg/m 2), cyclophosphamide (300 mg/m 2 up to 500 mg per week), and dexamethasone (20-40 mg) were administered weekly. SC daratumumab (1800 mg co-formulated with recombinant human hyaluronidase PH20 in 15 mL) was administered once weekly in cycles 1 and 2 and every 2 weeks in cycles 3 to 6. Patients in the D-VCd arm received only SC daratumumab after cycle 6, every 4 weeks (up to a total of 24 cycles from first dose). The primary endpoint was overall (ie, at any time) hematologic CR rate, defined here as normalization of free light chain (FLC) levels and ratio (FLCr) and negative serum and urine immunofixation, confirmed at a subsequent visit; normalization of uninvolved FLC level and FLCr were not required if involved FLC was lower than the upper limit of normal. Secondary endpoints included major organ deterioration progression-free survival (PFS), organ response rate, time to hematologic response, overall survival (OS), and safety. Results: A total of 388 patients were randomized to receive D-VCd (N=195) or VCd alone (N=193). At the May 2021 clinical cutoff, the median duration of treatment for D-VCd and VCd arms was 21.3 and 5.3 months, respectively. In the D-VCd arm, 149 patients (77.2%) received daratumumab monotherapy after completing 6 cycles of D-VCd; of those, 17 (11.4%) were still receiving treatment. The rates of deep hematological responses favored the D-VCd treatment arm (Table). At a median follow-up of 25.8 months, the rate of hematologic CR was significantly higher in the D-VCd arm vs the VCd arm (59.5% vs 19.2%; odds ratio [95% confidence interval (CI)], 6.03 [3.80-9.58]; P<0.0001). Similarly, more patients achieved a very good partial response or better (≥VGPR) (D-VCd vs VCd, 79.0% vs 50.3%; odds ratio [95% CI], 3.74 [2.39-5.86]; P<0.0001). Among patients who responded, the median time from randomization to ≥VGPR was shorter in the D-VCd arm (0.56 months) vs the VCd arm (0.82 months). Comparable to the cardiac response analysis at 6 months (D-VCd vs VCd, 42% vs 22%), greater cardiac response rates were achieved with D-VCd compared with VCd at 18 months (53% vs 24%). Similarly, renal response rates remained superior with D-VCd vs VCd alone at 18 months (58% vs 26% compared with 6 months [54% vs 27%]). A total of 79 deaths occurred (D-VCd, N=34; VCd, N=45). In the D-VCd arm, only 1 additional grade 3/4 treatment-emergent adverse event occurred over 18 months vs 12 months (119 [61.7%] vs 118 [61.1%] patients) and no additional infusion-related reactions were reported. OS will be analyzed and major organ deterioration PFS will be updated after approximately 200 events have occurred. Conclusions: These results demonstrate the sustained clinical benefits of D-VCd vs VCd in terms of hematologic and organ responses with longer follow-up, although it should be noted that many patients in the D-VCd arm received daratumumab monotherapy following 6 cycles of D-VCd, while patients in the VCd group stopped study treatment. Nevertheless, the study continues to support the use of D-VCd over VCd alone in patients with newly diagnosed AL amyloidosis. Following its recent approval, D-VCd represents a new SOC for patients with AL amyloidosis. Figure 1 Figure 1. Disclosures Comenzo: Prothena Biosciences: Consultancy, Research Funding; Takeda: Research Funding; Unum: Membership on an entity's Board of Directors or advisory committees, Research Funding; Karyopharm: Research Funding; Caelum: Consultancy, Research Funding; Sanofi-Aventis: Membership on an entity's Board of Directors or advisory committees; Janssen: Patents & Royalties: WO2016187546A1, Research Funding. Palladini: Pfizer: Honoraria; Siemens: Honoraria; Janssen Global Services: Honoraria, Other: advisory board fees. Kastritis: Pfizer: Consultancy, Honoraria, Research Funding; Takeda: Honoraria; Amgen: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Genesis Pharma: Honoraria. Minnema: Janssen: Consultancy; BMS: Consultancy; Kite/Gilead: Consultancy; Celgene: Other: Travel expenses; Alnylam: Consultancy; Cilag: Consultancy. Wechalekar: Amgen: Research Funding; Janssen: Consultancy; Takeda: Honoraria; Celgene: Honoraria; Caelum Biosciences: Other: Clinical Trial Funding; Alexion, AstraZeneca Rare Disease: Consultancy. Jaccard: Pfizer: Honoraria; Abbvie: Honoraria; Janssen: Membership on an entity's Board of Directors or advisory committees. Dispenzieri: Janssen: Consultancy, Research Funding; Sorrento Therapeutics: Consultancy; Oncopeptides: Consultancy; Alnylam: Research Funding; Pfizer: Research Funding; Takeda: Research Funding. Lee: Karyopharm: Consultancy; Celgene: Consultancy; Takeda Pharmaceuticals: Consultancy, Research Funding; Amgen: Consultancy, Research Funding; GlaxoSmithKline: Consultancy, Research Funding; Sanofi: Consultancy; Genentech: Consultancy; Legend Biotech: Consultancy; Janssen: Consultancy, Research Funding; Oncopetides: Consultancy; Bristol Myers Squibb: Consultancy; Regeneron: Research Funding. Sanchorawala: Oncopeptide: Research Funding; Karyopharm: Research Funding; Sorrento: Research Funding; Pfizer: Honoraria; Proclara: Membership on an entity's Board of Directors or advisory committees; Regeneron: Membership on an entity's Board of Directors or advisory committees; Caelum: Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Membership on an entity's Board of Directors or advisory committees; Prothena: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Research Funding; Celgene: Research Funding. Gibbs: AbbVie: Consultancy; Janssen, Celgene, Amgen, Takeda, BMS and Pfizer: Consultancy, Honoraria. Mollee: Janssen, Pfizer: Research Funding; Amgen, BMS, Janssen, Caelum, EUSA, Pfizer, SkylineDx, Takeda: Membership on an entity's Board of Directors or advisory committees, Other: No personal fees received. Venner: BMS: Honoraria; Amgen: Research Funding; Celgene: Research Funding; Amgen: Honoraria; Takeda: Honoraria; Janssen: Honoraria; Sanofi: Honoraria; Pfizer: Honoraria. Schönland: Janssen: Honoraria, Other: Travel grants, Research Funding; Pfizer: Honoraria; Takeda: Honoraria, Other: Travel grants; Prothena: Honoraria, Other: Travel grants; Sanofi: Research Funding. Suzuki: Abie: Honoraria; Sanofi: Honoraria; Novartis: Honoraria; ONO: Honoraria; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; Janssen: Consultancy, Honoraria. Kim: BMS: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding. Cibeira: Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Akcea: Honoraria, Membership on an entity's Board of Directors or advisory committees. Beksac: Oncopeptides: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Libby: Genentech: Research Funding; BMS: Research Funding; GSK: Research Funding; Janssen: Consultancy, Research Funding. Valent: Caelum Biosciences: Other: Clinical Trial Funding; Celgene Corporation: Speakers Bureau; Takeda Pharmaceuticals: Speakers Bureau; Amgen: Speakers Bureau. Hungria: Amgen, BMS, Celgene, Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings/travel ; Abbvie: Honoraria; Sanofi: Honoraria, Other: Support for attending meetings/travel ; Takeda: Honoraria. Wong: Amgen: Consultancy; Genentech: Research Funding; Fortis: Research Funding; Janssen: Research Funding; GloxoSmithKlein: Research Funding; Dren Biosciences: Consultancy; Caelum: Research Funding; BMS: Research Funding; Sanofi: Membership on an entity's Board of Directors or advisory committees. Rosenzweig: Janssen: Consultancy, Speakers Bureau; Bristol Myers Squibb: Speakers Bureau; Akcea: Speakers Bureau; Takeda: Speakers Bureau; Onocopeptides: Speakers Bureau. Bumma: Amgen, Sanofi: Speakers Bureau; Janssen, Oncopeptides, Sanofi: Consultancy. Tran: Janssen: Current Employment, Current equity holder in publicly-traded company. Qin: Janssen: Current Employment. Khaled: Jazz: Honoraria; Astellas: Honoraria; Alexion: Honoraria, Speakers Bureau; Omeros: Honoraria; Janssen: Current Employment. Vermeulen: Janssen: Current Employment, Current equity holder in publicly-traded company.

Abstract Introduction: Renal light chain (AL) amyloidosis typically manifests as proteinuria with or without renal failure and is associated with a risk of progression to renal replacement therapy (RRT). A significant reduction in circulating amyloidogenic light chain is needed to achieve a renal response. Current renal response criteria are binary defining a renal response as >30% reduction in 24-h proteinuria without worsening estimated glomerular filtration rate (eGFR). Several studies suggest that greater reduction in proteinuria following successful therapy improves renal and overall survival. Methods: AL amyloidosis patients diagnosed between 2010 to 2015, achieving at least hematological partial response (hemPR) to therapy and with renal involvement (defined as 24-h non-selective proteinuria >0.5 g/24-h) were included. Four predefined renal response categories were formulated based on reduction level in pretreatment 24-h proteinuria in the absence of renal progression (≥25% decrease in eGFR): renal complete response (renCR, 24-h proteinuria ≤200 mg/24-h); renal very good partial response (renVGPR, >60% reduction in 24-h proteinuria); renal partial response (renPR, 31-60% reduction in 24-proteinuria); and renal no response (renNR, 30% or less reduction). Renal response was assessed at landmark (6-, 12-, and 24 months from treatment initiation) and as best renal response. Graded renal responses were assessed as predictors for time from diagnosis to RRT and overall survival. Results: Seven hundred and thirty-seven patients were included. The median age was 63. The breakdown of renal stage was: I, 34%; II, 52%; and III, 14%. Eighty percent of patients received 1 line of therapy within 12 months of their diagnosis. Bortezomib-based therapy was given to 60% of the patients; 28% received autologous stem cell transplantation (ASCT) as their first line therapy. Hematological CR was achieved in 44% of patients, followed by hematological very good partial response (38%) and hemPR (18%). RRT was required during follow-up in 15% of patients (n=108) with a median time from diagnosis to RRT of 18 (IQR 6-43) months. Twenty-eight percent of the patients died. The median follow-up of the surviving patients was 69 months (IQR 56-86). Reduction in 24-h proteinuria from baseline improved over time with a median reduction of 34%, 50% and 71% at 6-month, 12-month, and 24-months, respectively. At best response, renCR, renVGPR, renPR and renNR were achieved in 27% (n=199), 34% (n=247), 15% (n=112) and 24% (n=179) of patients, respectively. The median time to best renal response among renal responders was 17 (IQR 8-31) months, longer for renCR (23 months, IQR 10-40) compared to renVGPR (16 months, IQR 9-27) or renPR (11 months, IQR 6-19). A renal response as early as 6 months after therapy initiation was able to predict time to RRT with an increase in RRT risk with lower level of renal response at that time point (5-year RRT risk 0%, 3%, 9% and 16% for renCR, renVGPR, renPR and renNR, respectively, P<0.001, Figure 1A). Prediction of risk for RRT based on renal response depth improved at 12- and 24-months (Figure 1B-C) and at best renal response (Figure 1D). Overall survival discrimination based on renal response depth was noted as early as 12 months from therapy initiation and improved with time. Renal response criteria as best response were tested in a univariate analysis and multivariable proportional hazard models for time to RRT and OS. The graded renal response criteria demonstrated an independent prognostic role for time to RRT and OS. Along with renal stage, graded renal responses were the strongest predictors for time to RRT. Conclusions: We validated new graded renal response criteria based on reduction in 24-h proteinuria. These 4-level renal response criteria highlight the importance of achieving a deep renal response to improve renal and overall survival. These findings will allow clinicians to make decisions on therapy changes or augmentation based on response depth as early as 6-months, before irreversible renal failure develops. Figure 1 Figure 1. Disclosures Palladini: Janssen Global Services: Honoraria, Other: advisory board fees; Siemens: Honoraria; Pfizer: Honoraria. Milani: Celgene: Other: Travel support; Janssen-Cilag: Honoraria. Schönland: Sanofi: Research Funding; Prothena: Honoraria, Other: Travel grants; Janssen: Honoraria, Other: Travel grants, Research Funding; Takeda: Honoraria, Other: Travel grants; Pfizer: Honoraria. Hegenbart: Akcea: Honoraria; Alnylam: Honoraria; Janssen: Consultancy, Research Funding; Prothena: Research Funding; Pfizer: Consultancy, Honoraria. Dispenzieri: Oncopeptides: Consultancy; Alnylam: Research Funding; Sorrento Therapeutics: Consultancy; Pfizer: Research Funding; Takeda: Research Funding; Janssen: Consultancy, Research Funding. Kumar: Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncopeptides: Consultancy; Carsgen: Research Funding; Beigene: Consultancy; Novartis: Research Funding; Bluebird Bio: Consultancy; Amgen: Consultancy, Research Funding; Roche-Genentech: Consultancy, Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Tenebio: Research Funding; Antengene: Consultancy, Honoraria; BMS: Consultancy, Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding. Kastritis: Amgen: Consultancy, Honoraria, Research Funding; Genesis Pharma: Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Takeda: Honoraria; Pfizer: Consultancy, Honoraria, Research Funding. Dimopoulos: Takeda: Honoraria; Janssen: Honoraria; Beigene: Honoraria; BMS: Honoraria; Amgen: Honoraria. Liedtke: Takeda: Membership on an entity's Board of Directors or advisory committees; Janssen Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Kite: Membership on an entity's Board of Directors or advisory committees; Kura Oncology: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Caelum: Membership on an entity's Board of Directors or advisory committees, Other: Clinical Trial Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria; Alnylam: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees. Witteles: Pfizer: Honoraria, Research Funding; Alnylam: Honoraria, Research Funding; Eidos: Research Funding. Sanchorawala: Pfizer: Honoraria; Takeda: Research Funding; Celgene: Research Funding; Prothena: Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Membership on an entity's Board of Directors or advisory committees; Regeneron: Membership on an entity's Board of Directors or advisory committees; Proclara: Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncopeptide: Research Funding; Karyopharm: Research Funding; Sorrento: Research Funding; Caelum: Membership on an entity's Board of Directors or advisory committees, Research Funding. Landau: Takeda, Janssen, Caelum Biosciences, Celgene, Pfizer, Genzyme: Membership on an entity's Board of Directors or advisory committees; Takeda: Research Funding; Genzyme: Honoraria. Cibeira: Celgene: Honoraria; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Akcea: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Wechalekar: Caelum Biosciences: Other: Clinical Trial Funding; Amgen: Research Funding; Janssen: Consultancy; Celgene: Honoraria; Takeda: Honoraria; Alexion, AstraZeneca Rare Disease: Consultancy. Gertz: Akcea Therapeutics, Alnylam Pharmaceuticals Inc, Prothena: Consultancy; Aurora Biopharma: Other: Stock option; Ionis Pharmaceuticals: Other: Advisory Board; AbbVie Inc, Celgene Corporation: Other: Data Safetly & Monitoring; Akcea Therapeutics, Ambry Genetics, Amgen Inc, Celgene Corporation, Janssen Biotech Inc, Karyopharm Therapeutics, Pfizer Inc (to Institution), Sanofi Genzyme: Honoraria.

Abstract Introduction: Binary cardiac response assessment using NT-proBNP is prognostic in light chain (AL) amyloidosis. Previous studies suggested that refining the criteria to multi-level cardiac responses improves prognostic prediction. We validate a graded cardiac response assessment tool in AL amyloidosis using NT-proBNP or BNP. Methods: In this retrospective, multicenter study AL amyloidosis patients who were diagnosed between 2010 and 2015, achieving at least a hematological partial response (PR) within 12 months of diagnosis and were evaluable for cardiac response (defined as baseline NT-proBNP >650 pg/mL or BNP >150 pg/mL) were included. The following response criteria were tested: cardiac complete response (carCR, nadir NT-proBNP≤350 pg/mL or BNP≤80 pg/mL); cardiac very good partial response (carVGPR, >60% reduction in NT-proBNP/BNP); Cardiac PR (carPR 31-60% reduction); and cardiac non response (carNR, ≤30% reduction). Response was assessed at fixed time points (6, 12 and 24 months from therapy initiation) and at best response. The primary outcome was overall survival based on depth of cardiac response. Multivariate Cox proportional models were analyzed to determine independent prognostic factors for OS and time to cardiac progression using variables with p-value <0.1 in a univariate analysis. Results: Six hundred and fifty-one patients were included. The median age was 64 years. Mayo 2004 cardiac stage II, IIIA and IIIB was present in 47.5%, 38% and 14.5% of patients, respectively (by definition, patients with Mayo stage I do not have cardiac amyloidosis evaluable for response). Seventy-six percent of patients received only one line of therapy within the initial 12 months of diagnosis. Bortezomib-based therapy was the most common (70.2% of patients) followed by autologous stem cell transplantation (ASCT) in 15.7% of patients. Hematological CR, hematological VGPR and hematological PR as best response was achieved in 38%, 39% and 23% of patients, respectively. Forty-three percent of the patients have died, with 36% of the patients dying within 5-years of diagnosis. The median follow-up of the surviving patients is 70 months (IQR 56-84). Cardiac response was evaluable using NT-proBNP in 494 patients (75.9%), BNP in 109 patients (16.7%) and both NT-proBNP and BNP in 48 patients (7.4%). The latter two were grouped together for further analysis. The median time to best cardiac response among responders was 12 months (IQR 7-21 months; 18 months for carCR, 11.5 months for carVGPR and 9.5 months for carPR). Cardiac response improved over time with a median percentage reduction in NT-proBNP/BNP compared to baseline of 15%, 37% and 54%, at 6, 12 and 24 months respectively. Cardiac responses at 6-, 12- and 24-months are depicted in Figure 1A. At best cardiac response, carCR, carVGPR, carPR and carNR were achieved in 16%, 26%, 23% and 35% of patients, respectively. Patients who achieved a carCR had lower cardiac stage at diagnosis compared to patients who achieved carVGPR or carPR (stage II 65% vs 47% vs 47%, respectively; P<0.001). At least carPR at 6 and 12 months and at least carVGPR at 24-months was associated with better survival compared with a lower depth of response. At best cardiac response, deeper cardiac response was associated with a longer survival (5-year OS 93%, 80%, 62% and 35% for carCR, carVGPR, carPR and carNR, respectively; P<0.001, Figure 1B). A 2-year landmark analysis (excluding early deaths not evaluable for cardiac response depth) confirmed improved survival with a deeper cardiac response (5-year OS 93%, 82%, 70% and 58%, P<0.001; Figure 1C). These cardiac response criteria were independent predictors of survival and time to cardiac progression (>30% rise in NT-proBNP/BNP) in multivariate analysis that included age, type of first line therapy, light chain burden, cardiac stage, and hematological response. Conclusions: We validated the prognostic value of graded cardiac response. These response criteria allow better discrimination of patient populations and assessment of treatment effectiveness in an era of improved therapies for AL amyloidosis. The study emphasizes the importance of early diagnosis which increases the likelihood of deep and durable cardiac responses. Figure 1 Figure 1. Disclosures Dispenzieri: Oncopeptides: Consultancy; Pfizer: Research Funding; Sorrento Therapeutics: Consultancy; Takeda: Research Funding; Alnylam: Research Funding; Janssen: Consultancy, Research Funding. Palladini: Siemens: Honoraria; Pfizer: Honoraria; Janssen Global Services: Honoraria, Other: advisory board fees. Schönland: Janssen: Honoraria, Other: Travel grants, Research Funding; Takeda: Honoraria, Other: Travel grants; Sanofi: Research Funding; Pfizer: Honoraria; Prothena: Honoraria, Other: Travel grants. Hegenbart: Alnylam: Honoraria; Janssen: Consultancy, Research Funding; Prothena: Research Funding; Pfizer: Consultancy, Honoraria; Akcea: Honoraria. Kumar: Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Carsgen: Research Funding; Novartis: Research Funding; Merck: Research Funding; Tenebio: Research Funding; Bluebird Bio: Consultancy; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche-Genentech: Consultancy, Research Funding; Antengene: Consultancy, Honoraria; Oncopeptides: Consultancy; Amgen: Consultancy, Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Beigene: Consultancy; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Research Funding; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding. Kastritis: Genesis Pharma: Honoraria; Takeda: Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding. Dimopoulos: Beigene: Honoraria; Takeda: Honoraria; BMS: Honoraria; Janssen: Honoraria; Amgen: Honoraria. Liedtke: GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees; Kite: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Janssen Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria; Sanofi: Membership on an entity's Board of Directors or advisory committees; Alnylam: Membership on an entity's Board of Directors or advisory committees; Caelum: Membership on an entity's Board of Directors or advisory committees, Other: Clinical Trial Funding; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Kura Oncology: Membership on an entity's Board of Directors or advisory committees. Witteles: Eidos: Research Funding; Alnylam: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding. Sanchorawala: Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Research Funding; Proclara: Membership on an entity's Board of Directors or advisory committees; Prothena: Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Membership on an entity's Board of Directors or advisory committees; Caelum: Membership on an entity's Board of Directors or advisory committees, Research Funding; Regeneron: Membership on an entity's Board of Directors or advisory committees; Takeda: Research Funding; Karyopharm: Research Funding; Oncopeptide: Research Funding; Pfizer: Honoraria; Sorrento: Research Funding. Landau: Genzyme: Honoraria; Takeda: Research Funding; Takeda, Janssen, Caelum Biosciences, Celgene, Pfizer, Genzyme: Membership on an entity's Board of Directors or advisory committees. Cibeira: Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Akcea: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Gertz: Akcea Therapeutics, Ambry Genetics, Amgen Inc, Celgene Corporation, Janssen Biotech Inc, Karyopharm Therapeutics, Pfizer Inc (to Institution), Sanofi Genzyme: Honoraria; Akcea Therapeutics, Alnylam Pharmaceuticals Inc, Prothena: Consultancy; AbbVie Inc, Celgene Corporation: Other: Data Safetly & Monitoring; Ionis Pharmaceuticals: Other: Advisory Board; Aurora Biopharma: Other: Stock option.

Abstract Background: Advances in supportive care and novel therapies have driven improved outcomes for patients with Multiple myeloma (MM) and Light Chain Amyloidosis (AL). Unfortunately, this progress demands a heavy toll - higher patient costs. Financial toxicity (FT) is the adverse impact of cancer on a patient's financial well-being, contributing to increased distress, lower medication compliance, and even reduced survival. We aimed to evaluate MM and AL patients for financial toxicity over time to better understand its impact on various quality of life (QOL) domains. Methods: Adult patients with MM or AL that receive care at Mayo Clinic, Rochester MN, were recruited for a prospective study between December 2019 and March 2021. FT was measured using the validated COmprehensive Score for financial Toxicity (COST) questionnaire at the time of enrollment, 3 months, and 6 months follow-up. COST scores range from 0-44, with higher scores indicating lower FT. We defined patients with a COST score of ≤ 23 as having substantial FT. Domains of QOL were assessed via the Patient Reported Outcome Measurement Information System (PROMIS)-29 survey. Patient demographics and clinical information were abstracted from the electronic medical record. Statistical analysis included a comparison of COST scores among groups through Wilcoxon rank-sum, Kruskal-Wallis, and Jonckheere-Terpestra tests for binary, unordered, and ordered categorical variables, respectively. Results: One hundred and sixteen patients (96 MM, 83%; AL 20, 17%) enrolled in this study. The cohort is characterized as follows: 49% age 65+ (51% age 35-64), 54% male, 93% White, 4.3% Black, 3.5% Hispanic, 44% with incomes > USD 75k/yr (26% < USD 50k/yr), 77% with at least some college education (32% graduate or doctoral degree), 52% insured through Medicare (4.3% through Medicaid), 36% employed (53% retired), and 71% married (16% divorced). Forty-three percent of patients enrolled in the study were newly diagnosed (56% relapsed), and 72% had received an autologous stem cell transplant. Baseline mean COST score was25.9 (N=116; SD 10.2), with 37% reporting FT. A total of 101 patients (85 MM; 16 AL) completed a baseline and either 3- or 6-month COST survey. Thirty-eight of these patients (38%) reported FT at the time of enrollment. Among those reporting baseline FT, 71% continued to report FT at 3 or 6 months; 29% showed reduced FT. Of the 62% of patients who reported low FT at baseline, 78% showed continued low FT at 3 or 6 months; 22% showed increased FT. Results of longitudinal follow-up are outlined in Figure 1. FT was significantly associated with increased anxiety, depression, and pain intensity domains on the PROMIS-29. Substantial FT was associated with: women, Medicaid as primary insurance, and being divorced. FT was also greater in unemployed/disabled vs retired individuals. Conversely, low FT was associated with: males, earning > USD 75k/yr, Medicare as primary insurance, having at least some college education, being retired, and traveling 300+ miles for care. Financial toxicity did not differ significantly by age, race, ethnicity, disease status (newly diagnosed vs relapsed), or transplant status. Discussion : Financial toxicity was present in more than one-third of AL and MM patients in this high-earning and well-educated cohort. Financial toxicity was associated with increased anxiety, depression, and pain intensity, contributing to lower patient quality of life. Longitudinal follow-up has shown financial toxicity to be dynamic, necessitating routine evaluation of patient financial burdens. Future work will focus on automating FT assessment with incorporation into routine care and developing care processes to support patients. Figure 1 Figure 1. Disclosures Dispenzieri: Alnylam: Research Funding; Takeda: Research Funding; Pfizer: Research Funding; Oncopeptides: Consultancy; Sorrento Therapeutics: Consultancy; Janssen: Consultancy, Research Funding.

Abstract Introduction Systemic immunoglobulin light chain (AL) amyloidosis is a rare disease characterized by amyloid fibril deposits, most commonly in the heart and kidneys. Management of the disease relies primarily on off-label use of multiple myeloma therapies. No treatments are approved for AL amyloidosis in the relapsed/refractory setting. In the phase 3, open-label TOURMALINE-AL1 trial (NCT01659658), patients with relapsed/refractory AL amyloidosis were randomized 1:1 to receive either oral ixazomib plus dexamethasone (Id) or physician's choice (CH) in 28-day cycles, and followed until progression or unacceptable toxicity. An interim analysis demonstrated that Id was well tolerated and, although the primary endpoint of hematologic response rate was not met, time-to-event efficacy analyses consistently favored Id. We report an analysis of patient-reported outcome (PRO) data on health-related quality of life (HRQOL) and AL amyloidosis symptoms from TOURMALINE-AL1; such data for AL amyloidosis in general have been limited. Methods Four PRO instruments were used to collect data to support PRO-related secondary endpoints during the treatment period: the Functional Assessment of Cancer Therapy/Gynecologic Oncology Group Neurotoxicity subscale (FACT/GOG-Ntx), an amyloidosis symptom questionnaire (ASQ), the EuroQoL 5-Dimension 3-Level (EQ-5D-3L), and the Visual Analogue Scale (EQ VAS) were collected at screening, day 1 of each cycle, and end of treatment (EOT), and the 36-item Short Form General Health Survey version 2 (SF-36v2) was collected at screening, day 1 of every third cycle, and EOT. Analysis of PRO data included descriptive summaries of means and change from baseline and a linear mixed model (LMM) for repeated measures for patients in the intent-to-treat (ITT) population with a baseline and at least one postbaseline PRO-specific assessment. No adjustment was made for multiple comparisons. Data cutoff date was 20 February 2019. Results The ITT population included 168 patients (Id: n=85; CH: n=83), who completed up to 58 cycles (Id) and up to 43 cycles (CH); median treatment duration was 11.7 vs 5.0 months, respectively. PRO compliance in the treatment period was high for all instruments (Figure). Baseline HRQOL as measured by the SF-36v2 and EQ VAS was similar between treatment arms. During the treatment period, SF-36v2 Mental and Physical Component Summary (MCS and PCS) scores remained stable relative to baseline and were similar between arms; the 8 subscale scores were also generally maintained over time, and mostly similar between arms. Least-squares (LS) mean changes from baseline were significantly higher (better HRQoL) for Id compared with CH at several cycles in the SF-36v2 Role Physical and Vitality subscales (p<0.05) (Figure); no subscales demonstrated significant differences favoring CH. Symptom burden as measured by the FACT/GOG-Ntx and ASQ was low at baseline, leaving little room for improvement. FACT/GOG-Ntx scores were generally maintained over time. In the treatment period, there were small but significant differences in LS mean changes from baseline favoring Id over CH at multiple cycles for 7 of the 11 individual items and the neurotoxicity and sensory summary scores; there were small but significant differences favoring CH over Id for 1 individual item (trouble hearing) at a few later cycles. The ASQ total score trended downward slightly (lower burden) during treatment after the first few cycles in both arms. There were significant differences per the LMM favoring Id over CH at cycles 7 and 21 (p<0.05). In both arms, EQ VAS scores trended upward (better HRQoL) during treatment and then declined slightly at EOT. (LMM analyses were not conducted for EQ-5D.) At EOT, a slight deterioration from baseline was observed in actual scores for SF-36v2 domains and summary scales, FACT/GOG-Ntx neurotoxicity and sensory subscales, and ASQ items and total score for both Id and CH. Conclusions Relapsed/refractory AL amyloidosis patients treated with Id experienced HRQOL and symptoms that were similar to or trended better than patients treated with CH. These data suggest that treatment with Id, although with a substantially longer treatment duration, did not have a negative impact on HRQOL in patients with relapsed/refractory AL amyloidosis, a population with currently no approved treatment options. Figure 1 Figure 1. Disclosures Sanchorawala: Regeneron: Membership on an entity's Board of Directors or advisory committees; Proclara: Membership on an entity's Board of Directors or advisory committees; Oncopeptide: Research Funding; Karyopharm: Research Funding; Sorrento: Research Funding; Pfizer: Honoraria; Caelum: Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Membership on an entity's Board of Directors or advisory committees; Prothena: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Research Funding; Celgene: Research Funding. Wechalekar: Caelum Biosciences: Other: Clinical Trial Funding; Alexion, AstraZeneca Rare Disease: Consultancy; Janssen: Consultancy; Celgene: Honoraria; Amgen: Research Funding; Takeda: Honoraria. Kim: Janssen, BMS: Research Funding. Schönland: Janssen: Honoraria, Other: Travel grants, Research Funding; Takeda: Honoraria, Other: Travel grants; Sanofi: Research Funding; Prothena: Honoraria, Other: Travel grants; Pfizer: Honoraria. Landau: Takeda, Janssen, Caelum Biosciences, Celgene, Pfizer, Genzyme: Membership on an entity's Board of Directors or advisory committees; Takeda: Research Funding; Genzyme: Honoraria. Fiona: Pfizer: Research Funding. Suzuki: Janssen: Consultancy, Honoraria; Abie: Honoraria; Sanofi: Honoraria; Novartis: Honoraria; ONO: Honoraria; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding. Dispenzieri: Sorrento Therapeutics: Consultancy; Oncopeptides: Consultancy; Pfizer: Research Funding; Alnylam: Research Funding; Janssen: Consultancy, Research Funding; Takeda: Research Funding. Comenzo: Karyopharm: Research Funding; Takeda: Research Funding; Unum: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi-Aventis: Membership on an entity's Board of Directors or advisory committees; Janssen: Patents & Royalties: WO2016187546A1, Research Funding; Prothena Biosciences: Consultancy, Research Funding; Caelum: Consultancy, Research Funding. Cherepanov: Takeda: Current Employment, Current equity holder in publicly-traded company. Hayden: Takeda: Current Employment, Current equity holder in publicly-traded company. Kumar: Takeda: Current Employment, Current holder of stock options in a privately-held company. Labotka: Takeda: Current Employment. Faller: Takeda Pharmaceuticals Co.: Current Employment; Viracta Therapeutics, Inc: Current holder of stock options in a privately-held company, Ended employment in the past 24 months, Membership on an entity's Board of Directors or advisory committees; Briacell, Inc: Current holder of stock options in a privately-held company. Kastritis: Amgen, Genesis Pharma, Janssen, Takeda: Consultancy; Amgen, Janssen, Pfizer: Research Funding; Amgen, Genesis Pharma, Janssen, Takeda, Pfizer: Honoraria.

Abstract Background: Systemic light chain (AL) amyloidosis is a plasma cell disorder characterized by multisystem deposition of misfolded immunoglobulin light chains produced by clonal plasma cells. Hematologic and organ responses with treatment have been shown to correlate with survival as early as 3 months from initiation of first-line treatment. Our group recently developed and validated a model integrating organ and hematologic responses for assessment of treatment outcomes at 6 months. Although current organ response criteria do not consider the depth of organ response, this has been shown to have prognostic utility in newly diagnosed patients. So, we designed this study to evaluate a composite hematologic and organ scoring system that also considers the depth of organ response at 1 to 6 months from initiation of first-line treatment. Methods: We included patients with AL amyloidosis who had at least one major organ involvement (cardiac, renal and/or liver involvement) and who had not started a second line treatment by 6 months from the time of initiating first-line treatment. For each patient, we calculated an organ response score and a hematologic response score at 1, 2, 3, 4, 5, and 6 months from initiation of first-line treatment. A score was assigned for each depth of hematologic response as follows: complete response=0, very good partial response=1, partial response=2, and no response/progressive disease=3). To calculate organ response, a score was assigned to each organ based on the depth of organ response (Muchtar et al. 2018): non-evaluable=0, complete response=1, very good partial response=2, partial response=3, and no response=4. The final organ response score was obtained by calculating the average of the individual involved organ scores. We then calculated the composite hematologic and organ response (HOR) score by adding the organ and hematologic responses at each interval and compared overall survival (OS) between patients with HOR score ≤ 5 (group 1) and those with score > 5 (group 2). Results: The cohort included 730 patients diagnosed with AL amyloidosis between February 10 th, 2006 and July 9 th, 2019. Median age was 63 (IQR: 56-69), and 65% were male. The involved light chain was Lambda in 75% of cases. Cardiac, renal, and liver involvement were found in 81%, 61%, and 17% of patients, respectively. Among all patients, 28% underwent autologous stem cell transplantation during their disease course. The median follow up in the entire cohort was 7.0 (95%CI: 6.4-8.0) years and OS was 3.6 (95%CI: 2.6-4.4) years. At 1 to 4 months, we observed a statistically significant difference in OS between patients with HOR score ≤5 vs. >5. However, there was no difference in OS between the 2 groups at 5 and 6 months. These results are presented in Table 1. Conclusion: A composite hematologic and organ response score that takes into consideration the depth of organ response can discriminate 2 groups of patients with distinct survival outcomes as early as 1 month from treatment initiation and maintains its predictive ability for up to 4 months. The lack of predictive ability beyond 4 months in this study may be due to limited sample size especially in group 2 as more patients achieve deeper responses with time. This approach can provide the basis for early changes in treatment but needs validation in future studies. Figure 1 Figure 1. Disclosures Dispenzieri: Janssen: Consultancy, Research Funding; Takeda: Research Funding; Sorrento Therapeutics: Consultancy; Oncopeptides: Consultancy; Pfizer: Research Funding; Alnylam: Research Funding. Gertz: Ionis Pharmaceuticals: Other: Advisory Board; Akcea Therapeutics, Ambry Genetics, Amgen Inc, Celgene Corporation, Janssen Biotech Inc, Karyopharm Therapeutics, Pfizer Inc (to Institution), Sanofi Genzyme: Honoraria; Aurora Biopharma: Other: Stock option; Akcea Therapeutics, Alnylam Pharmaceuticals Inc, Prothena: Consultancy; AbbVie Inc, Celgene Corporation: Other: Data Safetly & Monitoring. Kapoor: Ichnos Sciences: Research Funding; Karyopharm: Consultancy; Glaxo SmithKline: Research Funding; Pharmacyclics: Consultancy; Amgen: Research Funding; Cellectar: Consultancy; Sanofi: Consultancy; BeiGene: Consultancy; Regeneron Pharmaceuticals: Research Funding; Karyopharm: Research Funding; Sanofi: Research Funding; Takeda: Research Funding; AbbVie: Research Funding. Dingli: GSK: Consultancy; Sanofi: Consultancy; Janssen: Consultancy; Novartis: Research Funding; Apellis: Consultancy; Alexion: Consultancy. Kumar: Oncopeptides: Consultancy; Merck: Research Funding; Antengene: Consultancy, Honoraria; Bluebird Bio: Consultancy; Roche-Genentech: Consultancy, Research Funding; Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Research Funding; Novartis: Research Funding; Carsgen: Research Funding; Tenebio: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Beigene: Consultancy; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding.

Abstract Introduction/Objective Amyloidosis encompasses a heterogeneous group of disorders characterized by abnormal deposition of misfolded proteins leading to progressive organ failure. Accurate amyloid typing is essential for proper patient management, as treatment regimens vary dramatically across different types. Bone marrow (BM) biopsy, in conjunction with fat pad aspiration/biopsy, is often the first step in patients with suspected amyloidosis. Although BM involvement by AL amyloid has been previously characterized, little is known about the incidence, morphology and clinical phenotype of non-AL amyloid in BM. Methods/Case Report We retrospectively identified 1469 BM biopsies by querying our reference laboratory database of 19,298 specimens from myriad anatomic sites typed by mass spectrometry-based proteomics (LC-MS/MS). These were reviewed for frequency of amyloid types (N=1469), distribution of amyloid deposits (N=139), and clinical phenotypes (N=345), with particular emphases on cardiac involvement. Results (if a Case Study enter NA) We identified the following amyloid types: AL (N=1172; 79.8%), ATTR (transthyretin) (N=240; 16.3%), AH (immunoglobulin heavy chain) (N=38; 2.6%), AA (serum amyloid A) (N=17; 1.2%), and Aβ2M (β2-microglobulin) (N=2; 0.1%). ATTR deposits showed striking predilection for periosteal soft tissue and/or periosteal vessels, and rarely involved BM stroma and/or interstitial vessels, while AL variably involved these compartments. AA primarily involved interstitial vessels. Both AL and ATTR cases commonly had a monoclonal gammopathy (AL: 92.9%; ATTR: 62.5%) with concomitant cardiac amyloidosis (AL: 91.6%; ATTR: 100%). Compared to AL, ATTR patients had higher stage cardiac amyloidosis and lower overall survival. Conclusion ATTR is common in BM, constituting16.3% of cases in our cohort. Rarer amyloid types, such as AA, AH and AB2M can also occur in BM. ATTR was frequently identified in patients with concomitant monoclonal gammopathy, in whom AL may have been suspected. Although ATTR deposits have distinctive morphologic distribution, primarily involving periosteal soft tissue and/or periosteal vessels and rarely involving BM stroma and/or interstitial vessels, there is considerable morphologic overlap with AL. Therefore, it is imperative to type BM amyloidosis, preferably by LC-MS/MS, to ensure proper patient management. Furthermore, BM involvement by ATTR may be a marker for advanced stage of disease.