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SummaryThe severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2)‐associated coronavirus disease 2019 (COVID‐19) is primarily manifested as a respiratory tract infection, but may affect and cause complications in multiple organ systems (cardiovascular, gastrointestinal, kidneys, haematopoietic and immune systems), while no proven specific therapy exists. The challenges associated with COVID‐19 are even greater for patients with light chain (AL) amyloidosis, a rare multisystemic disease affecting the heart, kidneys, liver, gastrointestinal and nervous system. Patients with AL amyloidosis may need to receive chemotherapy, which probably increases infection risk. Management of COVID‐19 may be particularly challenging in patients with AL amyloidosis, who often present with cardiac dysfunction, nephrotic syndrome, neuropathy, low blood pressure and gastrointestinal symptoms. In addition, patients with AL amyloidosis may be more susceptible to toxicities of drugs used to manage COVID‐19. Access to health care may be difficult or limited, diagnosis of AL amyloidosis may be delayed with detrimental consequences and treatment administration may need modification. Both patients and treating physicians need to adapt in a new reality.

LBA3 Background: Bortezomib (btz) combined with lenalidomide (len) and dexamethasone (dex) (VRd) is a standard initial therapy for NDMM. Carfilzomib (cfz), a next-generation proteasome inhibitor, in combination with len-dex (KRd) has shown higher efficacy in phase II trials. This randomized phase III trial was designed to examine if KRd improves progression free survival (PFS) compared to VRd in NDMM (current results), and whether indefinite maintenance with len improves OS compared with two-year maintenance (to be analyzed once data matures). Methods: Patients (Pts) with NDMM, were randomized to receive VRd or KRd in a 1:1 fashion for 36 weeks followed by a second randomization (1:1) to indefinite versus two years of len maintenance. Pts without del17p, t (14;16), t(14;20), plasma cell leukemia or high-risk GEP70 profile, were enrolled. VRd arm included btz 1.3 mg/m2 on days(d) 1, 4, 8, and 11 (d 1, 8 for cycles 9-12), len 25 mg d 1-14, and dex 40 mg d 1, 2, 4, 5, 8, 9, 11, 12 of a 3-week (wk) cycle for 12 cycles, while pts in the KRd arm received cfz 36 mg/m2 d 1, 2, 8, 9, 15, 16 with len 25 mg daily on d 1-21 and dex 40 mg wkly, in 4 wk cycles for 9 cycles. Maintenance included len 15mg d 1-21 every 4 wks. The study was designed to detect a hazard ratio (HR)=0.75 with 80% power at 1-sided 2.5% alpha and 399 PFS events (progression or death regardless of intervening therapy). Results: The study accrued 1087 pts (VRd=542, KRd=545). The median age was 65y. Treatment, efficacy, and toxicity data are in the table. At the second of 3 planned interim analyses, with PFS HR=1.04 (95% CI, 0.8 to 1.3, p=0.74), futility was met. Median PFS was VRd=34.4m and KRd=34.6m; no differences were seen based on age (<65 or ≥65), presence or absence of t(4;14) or ISS stage. The three-year OS (95% CI) was similar: VRd 84% (80 to 88) and KRd 86% (82 to 89). Conclusions: In this randomized phase 3 trial, KRd did not improve PFS compared with VRd in NDMM. A significantly higher rate of cardio-pulmonary and renal toxicity was observed with KRd, while neuropathy rates were higher with VRd. VRd remains the standard triplet induction regimen in standard and intermediate risk NDMM, and a suitable backbone for 4 drug combinations. Clinical trial information: NCT01863550 . [Table: see text]

TPS8554 Background: BCL-2 is an anti-apoptotic protein important for myeloma cell survival. Venetoclax (Ven) is a highly selective, potent, oral BCL-2 inhibitor, that has shown promise in clinical studies as monotherapy or in combination with other agents in patients with t(11;14)-positive relapsed/refractory multiple myeloma (RRMM; Kumar et al. Blood. 2017; Costa et al. ASH 2018. Abstr. #303; Harrison et al. ASH 2019. Abstr. #142; Bahlis et al. ASH 2019. Abstr. #925; Kaufman et al. ASH 2019. Abstr. #926). Notably, t(11;14)-positive MM is more dependent on BCL-2 for cell survival, which, together with these clinical data, suggests that Ven combined with dexamethasone (Dex) may provide greater clinical benefit versus standard therapies, like pomalidomide (Pom), in this biomarker-defined patient population. This ongoing Phase 3 study (CANOVA; NCT03539744) aims to evaluate the safety and efficacy of VenDex vs PomDex in t(11;14)-positive RRMM. Methods: Eligible patients (≥18 years) must have t(11;14)-positive RRMM per central lab, an ECOG performance status ≤2, received ≥2 prior lines of therapy, previously received a proteasome inhibitor, and must be refractory to lenalidomide and last line of therapy. Patients cannot have history of treatment with Ven, Pom, or other BCL-2 inhibitors. Patients will be randomized 1:1 to Ven (800 mg orally, once-daily) or Pom (4 mg orally, once-daily on days 1-21 of 28-day cycles). Patients in both groups will receive 40 mg Dex (20 mg for patients ≥75 years) once weekly. Treatment will continue until disease progression, unacceptable toxicity, or withdrawal from study. Patients will be stratified based on age at randomization ( < 65 vs ≥65 years), prior lines of therapy (2 to 3 vs ≥4), and International Staging System stage at screening (I vs II vs III). The primary endpoint is progression-free survival (PFS) per independent review committee (IRC) assessment based on International Myeloma Working Group criteria. The final PFS analysis will be performed when approximately 147 PFS events per IRC are observed. Secondary endpoints are response rate, patient-reported outcomes, overall survival, duration of response, times to response and progression, minimal residual disease negativity rate, safety, and Ven pharmacokinetics. Approximately 244 patients will be enrolled; as of January 21, 2020, 28 patients have been randomized (from 19 sites in 12 countries) and enrollment is ongoing. Clinical trial information: NCT03539744 .

e20520 Background: Cytogenetic abnormalities detected by FISH are found in the majority of multiple myeloma (MM) patients. Although their prognostic value has been studied extensively, less is known about their association with disease characteristics and treatment response. Methods: To address these questions, we designed a retrospective study including 2031 Mayo Clinic patients diagnosed with MM from 2004 to 2018. We compared baseline characteristics and treatment outcomes between primary cytogenetic groups: t(11;14), t(4;14), t(14;16), (14;20), t(6;14), unknown IgH translocation/del and trisomy (without IgH translocation). These included 373, 177, 78, 20, 18, 228 and 791 patients respectively. Kruskal-Wallis and Fisher’s exact tests were used for categorical and continuous variables respectively. Time to next treatment (TTNT) was estimated using Kaplan-Meier method and compared using Log-Rank test. Results: t(4;14), t(14;16), t(6;14) and t(14;20) groups were associated with hemoglobin < 10 g/dL, beta2microglobulin > 5.5 µg/ml, ISS stage 3 and ≥50% bone marrow plasma cells. The latter 3 groups were also associated with renal dysfunction (Cr ≥2 mg/dL) and higher urinary monoclonal protein. t(4;14) was associated with IgA isotype, serum monoclonal protein ≥1g/dL and plasma cell labeling index ≥1%. Light chain myeloma was more prevalent in patients with t(11;14). Overall response rate (ORR) to proteasome inhibitor (PI) induction was higher for those with IgH translocations (any) compared to trisomies (85% vs 77% P = 0.02), while ORR was higher for those with trisomies with immunomodulatory drug (IMiD) induction (90% vs 78% P < 0.01). The rate of ≥ very good partial response was higher for patients with high risk IgH translocations [t(4;14), t(14;16) or t(14;20)] compared to standard risk with PI-IMiD combination treatment (88% vs 65% P < 0.01). Otherwise, response rates did not differ between these 2 groups. TTNT was longer in patients with trisomies compared to those with IgH translocation with IMiD or PI-IMiD treatments (32.2 vs 19 and 44 vs 27.4 months, respectively P < 0.01). For all cytogenetic groups, better treatment responses and longer TTNT were seen with PI-IMiD combinations compared to other treatments. Conclusions: t(4;14), t(14;16), t(6;14), and t(14;20) are associated with high risk disease characteristics. Patients with IgH translocations may have better response to PI induction compared to those with trisomies, while those with trisomies may have better response to IMiD treatment, with best outcomes for both seen with PI-IMiD combinations.

e20515 Background: IgA monoclonal proteins (MCPs), unlike IgG MCPs, often migrate in the beta region on serum protein electrophoresis (SPEP) which can lead to underestimation of their size due to the co-migration with physiologic proteins. In IgA multiple myeloma (MM), the utility of quantitative IgA levels in assessing disease response in comparison to SPEP is not well studied. Methods: We retrospectively analyzed 304 IgA MM patients, diagnosed between 2004 and 2018, with available serial MCP and quantitative IgA levels. Kaplan Meier analysis was used to estimate the median progression free survival (mPFS) using the IMWG criteria and our study definition of IgA progression (2 consecutive IgA values that are > 25% above the nadir IgA value and above upper limit of normal (ULN) of 356 mg/dL, and a detectable IgA MCP on serum immunofixation). The mPFS was defined as the time from treatment initiation until disease progression or death. Results: IgA MCP migrated in the beta region in 134 (44%) patients, and in the gamma region in 150 (56%) patients. At diagnosis the median MCP was 3 (IQR 1.9-4) g/dL and the median IgA was 3240 (IQR 2008-4420) mg/dL. The median time from treatment initiation to MCP nadir was 80 (IQR 42-144) days and median time to IgA nadir was 154 (IQR 90-238) days. At MCP nadir 40% of patients had an IgA above the ULN. All complete responders (n = 104) had normal IgA levels, with a median IgA of 54 (IQR 27-88) g/dL. A ≥90% decrease in IgA between treatment initiation and IgA nadir, compared to a < 90% decrease, was associated with a longer mPFS (34 vs. 20 months, p = 0.006) and overall survival (97 vs. 33 months, p = 0.003). Patients with serial MCP and IgA levels available prior to progression (n = 195) were used to compare the mPFS using the IMWG and IgA progression criteria. The mPFS using the IgA criteria was 32 (95% CI 29-39) months, versus 39 (95% CI 33-45) months using IMWG criteria. Overall, 92 (47%) patients progressed by both IMWG and IgA criteria. At the time of progression using the IgA criteria compared to at IMWG progression, the median hemoglobin was higher (13.3 vs. 11.6 g/dL, respectively, p < 0.001) and fewer patients had new symptomatic bone lesions (2% vs. 33%, respectively, p < 0.001). Conclusions: In IgA MM patients, monitoring quantitative IgA levels predicts disease response and allows for earlier detection of disease progression, prior to the development of end organ damage.

e20510 Background: pPCL is a rare and aggressive form of multiple myeloma (MM) with dismal survival outcomes compared to the remainder of MM patients. Several studies have validated the optimal cutoff for defining pPCL to be >5% circulating plasma cells (cPCs) on a peripheral blood smear due to equally poor outcomes in this less restrictive cohort. We evaluated the clinical outcomes and cytogenetic features of patients diagnosed with pPCL at our institution that were treated with novel agent induction therapies. Methods: We evaluated patients with pPCL diagnosed between 2000 – 2018 (using the 5% cut off) at Mayo Clinic, Minnesota. Data was extracted from a prospectively maintained database and from the review of electronic medical records. Patients were categorized as having high risk (HR) cytogenetics if any of the following abnormalities were present: del 17p, t(4;14), t(14;16) or t(14;20). Chi-square tests and Fisher exact tests were used to compare differences between sub-groups. Survival analysis was performed by the Kaplan-Meier method and differences assessed using the log rank test. Results: This cohort consisted of 67 patients with pPCL with a median age of 62 years (range: 34-91) of which 33 (46%) were male. The median follow up was 46 months (95% CI: 41 – 90). The median bone marrow plasma cell involvement was 84% (Range: 10 – 100) and the median cPCs percentage on the peripheral blood was 23% (range: 5 - 93). Data on primary cytogenetic abnormalities were available in 60 (85%) patients and the distribution was as follows: t(11;14) – 27 (45%), t(4;14) – 5 (8%), t(14;16) – 8 (13%), t(14;20)- 3(5%) and del 17p- 15(25%). All patients received novel agent induction therapy with 36 (54%) having received autologous stem cell transplant and 4 undergoing an allogeneic stem cell transplant. The median time to next therapy (TTNT) and overall survival (OS) for all patients was 13 months (95% CI: 9 – 17) and 24 months (95% CI: 19 – 40) respectively; 16 months and 51 months for standard risk (SR) vs. 10 months and 19 months for HR (P = 0.005 for OS), when stratified by cytogenetic risk. There were only 17 (31%) patients who were alive for ≥48 months since diagnosis (i.e. twice the median OS of this cohort); The absence of high risk cytogenetics (P = 0.049) and non-elevated LDH level (P = 0.047) at diagnosis predicted for achieving this survival goal. Conclusions: The outcomes of patients diagnosed with pPCL remain poor despite the use of novel agent induction therapy. However, some patients appear to do better than expected and this phenomenon may be influenced by the presence of HR cytogenetics.

e20506 Background: Autologous stem cell transplantation (ASCT) prolongs survival in patients with light chain (AL) amyloidosis. Mayo 2012 stage and increased plasma cell percentage (%PC) are known predictors for survival. Increased beta-2 microglobulin (B2M) predicts survival in patients with multiple myeloma. However, its prognostic effect in patients with AL amyloidosis undergoing ASCT is not known. Methods: We retrospectively reviewed patients who had a diagnosis of AL amyloidosis and were treated with ASCT between July-1996 and September-2017. Patients with creatinine > 1.2 mg/dL were excluded, as that affects B2M levels. The receiver operator curve was used to determine the best cutoff for B2M in predicting survival and was 2.5 mcg/mL. Baseline characteristics were compared between patients with B2M > 2.5 and ≤2.5. Progression-free survival (PFS) was defined as time from ASCT to relapse or death, whichever occurred first. Overall survival (OS) was calculated from ASCT to death of any cause. Univariate and multivariate analysis were done for OS. Results: Five-hundred patients were identified and 222 (44%) had a B2M > 2.5. These patients were more likely to be > 65 years old (32% vs. 17%, P = 0.0001), have Mayo 2012 stage III/IV (33% vs. 8%, P < 0.0001), have ≥3 organs involved (25% vs. 14%, P = 0.001), and have ≥10% PCs (56% vs. 40%, P = 0.0002) compared to patients with B2M ≤2.5. The median PFS and OS were shorter in patients with B2M > 2.5 (median PFS: 64 vs. 80 months, P = 0.03); (median OS: 104.9 vs. 175.5 months, P < 0.0001). On univariate analysis, predictors for OS included age > 65 (HR: 1.6, P = 0.001), Mayo 2012 stage III/IV (HR: 3.3, P < 0.0001), ≥3 organs involved (HR: 1.3, P = 0.06), ≥10% PC (HR: 1.5, P = 0.004), melphalan conditioning 200mg/m2 (HR: 0.28, P < 0.0001), and B2M > 2.5 (HR: 1.8, P < 0.0001). In a multivariate analysis, only Mayo 2012 stage III/IV (HR: 1.8, P = 0.006), melphalan conditioning 200mg/m2 (HR: 0.35, P < 0.0001), and B2M > 2.5 (HR: 1.7, P = 0.01) remained independent predictive of OS. Conclusions: Beta-2 microglobulin > 2.5 is an independent predictor for OS in AL amyloidosis patients undergoing ASCT and should be routinely measured.

8550 Background: Waldenström Macroglobulinemia (WM) is a rare lymphoplasmacytic malignancy characterized by the presence of a recurrent point mutation in the MYD88 gene (MYD88L265P) in 80-95% of cases. Patients with MYD88WT genotype comprise a small subset that responds poorly to ibrutinib and other Bruton tyrosine kinase inhibitors. We examined the characteristics and outcome of WM patients with MYD88WT genotype predominantly treated with non-BTK inhibitor based therapies. Methods: Patients with a diagnosis of WM seen at Mayo Clinic, Rochester, between 1996 and 2018 were included. Their characteristics and outcomes were assessed from the time of active disease. Marrow MYD88 genotyping was assessed with an allele specific PCR assay (analytic sensitivity 1%). Categorical and continuous variables were compared using Chi square and Wilcoxon tests, respectively. Time-to-event analyses were performed using Kaplan Meier test. Results: Of 986 patients with active WM, MYD88 genotype data were available in 331 (34 %) patients; 72 (22%) and 260 (78%) patients harbored MYD88WT and MYD88L265P genotypes, respectively. The median follow-up was 5.8 years (95% CI: 5.0-6.5 years) from active WM; 6 years MYD88WT vs 5.4 years for MYD88L265P cohort. Median age was 63 years and 66 years in the MYD88WT and MYD88L265P cohorts, respectively (p = 0.07) with 46% and 53% patients being ≥65 years of age, respectively (p = 0.36). Pre-treatment marrow lymphoplasmacytic (LPL) infiltrate (median 40% for MYD88WT vs 60% for MYD88L265P; p = 0.001) and beta-2 microglobulin (median 3 µg/mL for MYD88WT vs 3.9 µg/mL for MYD88L265P; p = 0.02) were lower in the MYD88WT compared to the MYD88L265P cohort; other laboratory parameters at active disease were comparable. Per IPSSWM prognostic criteria, MYD88WT had fewer patients in the high risk group (18% for MYD88WT vs 42% MYD88L265P; p = 0.03). Patients with MYD88WT had higher likelihood of histological transformation [18% for MYD88WT vs 4% for MYD88L265P; odds ratio 5.8 (95% CI: 2.5-13.5; p < 0.0001)]. Among patients with treatment data available, only 35 (11%) patients received ibrutinib. The 5-year overall survival (OS) from active disease was comparable (85% in MYD88WT vs 82% in MYD88L265P cohort; p = 0.7). Conclusions: MYD88WT genotype in WM is associated with lower marrow LPL infiltration, lower likelihood of high-risk IPSSWM categorization and a higher likelihood of histological transformation in comparison to MYD88L265P mutant subpopulation. MYD88 genotype does not affect the OS from active disease in predominantly non-BTK inhibitor treated patients.

8547 Background: Venetoclax (Ven) is a selective, potent BCL-2 inhibitor that has synergistic activity with bortezomib (B) and dexamethasone (d). In the Phase 3 BELLINI trial, addition of Ven to Bd significantly improved median progression-free survival (PFS) and response rates, including minimal residual disease (MRD) negativity, but resulted in increased mortality vs placebo (Pbo). Here, we determine whether MRD negativity was associated with longer PFS and OS in relapsed/refractory multiple myeloma (RRMM) patients treated with Ven+Bd in the BELLINI dataset. Methods: In BELLINI (NCT02755597), RRMM patients (pts) sensitive or naïve to proteasome inhibitors with 1-3 prior lines of therapy were randomized 2:1 to Ven (800 mg) or Pbo plus B (1.3 mg/m2) and d (20 mg). Next-gen sequencing MRD assessments were done on bone marrow aspirates at the time of suspected CR/sCR, and 6- and 12-months post confirmation of CR/sCR. Patients with a missing or indeterminate assessment were considered MRD positive. Evaluation of MRD in biomarker-defined subgroups (cytogenetics and BCL2 expression) was also performed and will be presented. Results: In total, 291 pts were randomized; 194 to Ven, 97 to Pbo. As of 13 Sep 2019, the median follow-up was 29 months. Ven + Bd demonstrated significantly higher MRD negativity rates ( < 10−5), including a higher proportion of pts achieving sustained MRD negativity (Table). In the Ven arm, the median (m)PFS was not reached for MRD negative pts vs 16.2 months for MRD positive pts (HR = 0.23, 95% CI: 0.10-0.54, p < 0.001). While the mOS was not reached in the Ven arm, OS was significantly longer for MRD negative vs MRD positive pts (HR = 0.25, 95% CI: 0.08-0.80, p = 0.0194). Conclusions: The addition of Ven to Bd resulted in deep and durable responses, including higher rates of MRD negativity. MRD negativity in the context of Ven was associated with prolonged survival in patients with RRMM, consistent with the broader MRD body of evidence with other therapies in MM. Clinical trial information: NCT02755597 . [Table: see text]