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SummaryBelantamab mafodotin (BLMF) is a B‐cell maturation antigen‐directed antibody‐drug conjugate, recently approved for advanced multiple myeloma (MM). The impact of BLMF‐induced ocular toxicity on patient outcomes is unknown. We studied a cohort of 38 consecutively seen patients treated with BLMF outside of trials. Of those, 75% experienced ocular toxicity, with 69% developing keratopathy. Among patients requiring ocular toxicity‐related permanent BLMF discontinuation (14%) or dose reduction (11%), 70% had progression of MM within a median of 3 months (95% confidence interval: 0.2–not reached) following BLMF interruption or dose reduction. Ocular toxicity is a major deterrent to the continuous use of BLMF in routine clinical practice. Measures to successfully prevent and mitigate ocular toxicity should be developed to achieve the full potential of this agent.

8022 Background: Bone marrow (BM) assessment of minimal residual disease (MRD) is being considered as a surrogate endpoint in clinical trials and is prognostic for survival in multiple myeloma (MM). Timing of BM assessment is variable across Chimeric Antigen Receptor T cell (CART) therapy trials and differs from standard of care practice. BM myeloma cell clearance can be detected by month 1 post CART, even before serum immunofixation becomes negative. BM is still hypocellular at month 1, thus prognostic value of MRD negative (MRDneg) at this timepoint is unclear. We examined impact of Day 30 MRD status in patients (pts) who received CART at Mayo Clinic. Methods: Medical records were reviewed retrospectively for MM pts who received CART between 8/2016 and 6/2021. PFS and OS were plotted by Kaplan-Meier method. Results: Sixty MM pts received CART and had BM biopsy at month 1. Median age was 62 yrs, 53% were male, and 78% were BM MRDneg by flow cytometry. Baseline demographics were similar between MRDneg and MRD+ (Table). Overall, 85% (40/47) who were month 1 BM MRDneg had i/u FLC<normal. Patients who achieved CR/sCR had higher rates of BM MRDneg (100% vs 61%, p<0.001) and i/u FLC< normal (89% vs 58%, p<0.001). At month 1, 24/60 (40%) pts had hypocellular BM. Serial BM samples at month 3 (n=35), 6 (n=28) and 12 (n=23) showed MRDneg rate of 93% (25/27), 56% (9/16) 58% (7/12), respectively.. Rate of hypocellularity was 54% (19/35), 32% (9/28) and 30% (7/23), respectively. Among the MRDneg/hypocellular pts at month 1, hypocellular BM was seen in 8/11 (73%) pts at month 3 and 2/4 (50%) pts at month 6 and 12. Compared to MRD+, pts who had BM MRDneg at months1 had longer PFS (Table). PFS was not statistically significantly different between pts who had BM MRDneg and were either hypocellular or not. MRDneg pts with i/u FLC<normal at months1 had better median PFS compared to those who did not. (MRD+:2.9 months (1.2-NR). MRDneg/FLC>normal: 4.9 months (2.3-NR). vs MRDneg/FLC<normal:17.9 months (11.8-NR), p<0.0001). Conclusions: Hypocellular BM is common in the 3 months post CART. Regardless of BM cellularity, BM MRDneg at month 1 correlates with deep response and prolonged PFS. Majority of BM MRDneg pts at month 1 also had FLC<normal. BM MRDneg status and FLC normalization were associated with longer survival. Our data support the continued evaluation of BM early post CART infusion as a prognostic tool. [Table: see text]

e20001 Background: High dose melphalan followed by autologous stem cell transplant (HDM-ASCT) remains the standard of care for transplant-eligible patients with newly diagnosed multiple myeloma (NDMM) despite advances in treatments. Achievement of complete response (CR) is associated with improved overall survival (OS) and progression-free survival (PFS); Minimal Residual Disease (MRD) negativity (-) using next generation flow cytometry with a sensitivity of 10-5 is strongly associated with improved PFS and OS. We investigated the rates of conversion to MRD(-), especially MRD(-) CR following HDM-ASCT in patients with NDMM. Methods: We retrospectively reviewed patients with NDMM who underwent early HDM-ASCT at Mayo Clinic Rochester from May 2018 to July 2019. Response assessment was conducted after induction and within 100 days post-ASCT based on 2016 IMWG criteria, except for using Mass-Fix instead of immunofixation. MRD was assessed in bone marrow using the established Euro Flow protocol with sensitivity of 10-5. The FISH assay was used to risk-stratify patients as high-risk (HR) and standard risk (SR) cytogenetics as per the mSMART guidelines. Primary outcome measure was the conversion to MRD(-) CR after ASCT. Secondary outcomes include the overall conversion to MRD(-) irrespective of IMWG response, the impact of HR cytogenetics and pre-ASCT IMWG response on conversion to MRD(-) CR. Results: Two-hundred and ten patients were included; 126 (60%) were male and median age 62 years (range 32–77 years). There were 78 (44%) patients with HR cytogenetics. Pre-ASCT, 23 patients (11%) achieved MRD(-) CR, and 66 (31%) patients achieved MRD(-) CR post ASCT. Of 187 patients not in MRD(-) CR pre-ASCT, 45 (24%) converted to MRD(-) CR. Table provides a breakdown of the conversion rate of pre-ASCT IMWG response category to MRD(-) CR post ASCT and patients with MRD(+) CR had the highest rate (78%) of conversion. The presence of HR cytogenetics did not impact rates of MRD(-) CR achievement post ASCT irrespective of pre-ASCT IMWG response (p = 1.0). Overall, irrespective of IMWG response, 43 (20%) patients were MRD(-) pre-ASCT (19 in VGPR, 24 in CR or better) and 102 (49%) patients were MRD(-) post-ASCT (36 in VGPR, 66 in CR or better). Among 85 patients in VGPR post-ASCT, 36 were MRD(-) of which 8 (22%) progressed, while 49 were MRD(+) of which 24 (49%) progressed (p = 0.014). Conclusions: Upfront HDM-ASCT in patients with NDMM leads to deeper responses with 24% converting to MRD(-) CR and more than doubling of the total rate of MRD(-) irrespective of IMWG response. [Table: see text]

e19562 Background: Considerable healthcare resource utilization and financial burden have been associated with the treatment of Waldenstrom Macroglobulinemia (WM); however, the impact of health insurance status on patient outcomes has not been explored. We aimed to assess the insurance-based outcome relationship in WM using the National Cancer Database (NCDB). Methods: We analyzed patient-level data obtained from the NCDB, a database representing more than 70% of newly diagnosed cancer cases nationwide. All newly diagnosed WM cases (n = 8540) between 2004 to 2017 were identified. Only patients who underwent treatment were included. Insurance status was recorded by assessing the primary payer at the time of diagnosis. Due to Medicare eligibility criteria, age-based (< 65 and ≥65 years) stratified analysis was conducted. Cox proportional hazards model was utilized to analyze survival. Time-to-event analysis was conducted based on date-of-diagnosis using the Kaplan-Meier method and log-rank test. Results: Analysis was conducted on 3878 patients after meeting inclusion criteria, with a median follow-up time of 54.6 months. Among patients < 65 years (n = 1249; median age: 58 years; male: 62.4%), those with non-private insurance had inferior survival on multivariate analysis (Table) after adjusting for patient demographics, comorbidities, income, education, treatment center characteristics, and treatment start time. Significant overall survival (OS) differences were seen in those < 65 years (log-rank p < 0.001), with 5-year OS highest among patients with private insurance 91.2%, compared to Medicaid 79.8%, uninsured 77.4%, and Medicare 70.2%. In patients < 65 years, compared to private insurance, uninsured patients were more likely to be of Black race, reside in lower income areas, and be treated at non-academic centers (all p < 0.05). Both Medicaid and Medicare patients < 65 years were more likely to have a higher Charlson-Deyo comorbidity index (> 1) and live in areas of lower educational attainment and household income compared to private insurance (all p < 0.05). In patients ≥65 years (n = 2629; median age: 75 years; 60.6% males), no insurance-based OS (log-rank p = 0.096) differences were seen. Conclusions: Based on our study, significant insurance-based disparities exist in WM, where patients < 65 years old who are uninsured, or non-privately insured are at a higher risk of mortality. While the root cause of these differences is not fully elucidated, efforts should focus on ensuring that all patients have equal access to care regardless of primary payer status.[Table: see text]

7566 Background: Parenteral limited-duration BR chemoimmunotherapy and continuous orally administered Ibr, a Bruton tyrosine kinase inhibitor, dominate the treatment landscape of WM, a rare B cell lymphoma. No trials have assessed the comparative effectiveness of these 2 vastly different approaches. We conducted a multiinstitutional, international, collaborative study to compare BR and single-agent Ibr in patients (pts) with treatment naïve (TN) WM. Methods: Data from 347 pts with active TN WM, seen between 2011 and 2021 in the US and Europe, were analyzed. The pts on rituximab maintenance were excluded. The modified IWWM-6 criteria (based on IgM alone) were used for response assessment. All time-to-event analyses were performed from the frontline therapy initiation, using the Kaplan-Meier method. Results: The median age of the pts treated with BR (n=208) and Ibr (n=139) was 66 (range 40-86) years (y) and 69 (39-97) y, respectively, (p=0.005). With a median follow up of 4.2 y (95% CI 3.8-4.5), the 4-y progression free survival (PFS) was 73% in each group, p=0.6, and 4-y overall survival (OS) was 94% (95% CI 91-98) in the BR group versus ( v) 82% (95% CI 75-90) in the Ibr group, p=0.01. In a bivariate analysis adjusting for age and the treatment type, only age emerged as a predictor for OS (HR 7.2, p=0.0001). Therefore, a 1:1 age-matched analysis of 246 pts who received Ibr (n=123) or BR (n=123) was performed. Pts with a known MYD88WT status who had received Ibr and their age matched controls on BR were excluded. The international prognostic scoring system (IPSS) WM was comparable between the 2 groups (Table). A higher proportion of pts on BR attained very good partial or deeper response (≥VGPR) as the best response in comparison to the pts on Ibr (Table). The 4-y PFS for the BR and Ibr groups was similar [72% (95% CI 63-82) v 78% (95% CI 70-87), p=0.14] and 4-y OS was 95% (95% CI 91-99) with BR v 86% (95% CI 80-93) with Ibr (p=0.3). Premature discontinuation, during active treatment, due to adverse effects (AEs) or lack of response was noted in 13% and 33% of pts on BR and Ibr, respectively. A detailed assessment of the AEs will be presented at the meeting. Conclusions: Both BR and Ibr lead to comparable outcomes in pts with TN WM, although deeper responses are attained with BR. These findings require confirmation in prospective studies. For pts who harbor MYD 88L265P mutation, selection between the 2 approaches should be dictated by their potential toxicities, pt comorbidities, pt/clinician preference (parenteral fixed-duration v continuous oral) and access to therapies. [Table: see text]

110 Background: Sarcopenia or a loss of muscle mass increases with aging and is associated with increased overall mortality in patients with cancer. Recent advances in machine learning–based CNN algorithms have allowed for the rapid processing of digital images to produce image classifications of body composition. Since incidence of MM is highly associated with aging, we sought to determine if the presence of sarcopenia, as determined by utilizing this machine learning–based CNN algorithm on CT images, had prognostic value in patients with NDMM. Methods: We identified all patients with NDMM from January 2003 to July 2019 who had a standard-dose CT scan that included the L3 vertebral level performed within 6 months of diagnosis. Using a machine learning–based CNN-algorithm, abdominal CT images were analyzed to measure muscle area. These measurements were normalized by dividing the area values by the height of the patient squared (m2) to obtain skeletal muscle index (SMI) values. Patients were categorized as sarcopenic according to international gender-specific consensus cutoffs for SMI (male: < 55 cm2/m2 and female: < 39 cm2/m2). Patients with the following FISH cytogenetics were considered high risk (HR): t(4;14), t(14;16), t(14;20), and deletion 17p/monosomy 17 whereas the remainder were standard risk (SR). Survival analysis was performed using the Kaplan-Meier method and compared via the log-rank method. Results: The study cohort consisted of 344 patients. 68 (20%) were categorized as HR based on FISH cytogenetics.187 (54%) patients were sarcopenic based on their peri-diagnosis standard-dose CT scan. Sarcopenic patients were more likely to have ISS-3 disease (45% vs. 30%; p =.023), be male (73% vs. 48%; p <.001), and be ≥ age 75 (27% vs. 14%; p =.002) compared to non-sarcopenic patients. The median OS for patients with HR FISH and ISS 2 / 3 disease was 40 months and 57 months respectively compared to 90 months and 119 months for those with SR FISH and ISS-1 disease respectively (FISH: p <.004; ISS: p <.001). The median OS for sarcopenic patients was 44 months compared to 90 months for those not sarcopenic (p <.001). The time to next therapy (TTNT) for sarcopenic patients was 39 months compared to 45 months for those not sarcopenic (p =.05). In a multivariable model, the presence of sarcopenia (HR 1.64, 95% CI, 1.05–2.56; p =.03) retained significance in the presence of HR FISH, ISS 2 / 3 disease, and age ≥ 75. Conclusions: Gender-specific sarcopenia identified by a machine learning–based CNN algorithm significantly affects OS in patients with NDMM and is independent of age, ISS stage, and cytogenetic status. Future studies utilizing this machine learning–based methodology of assessing sarcopenia in larger prospective clinical trials are required to validate these findings.

Abstract Almost all patients with multiple myeloma (MM) eventually relapse, either asymptomatically or with end-organ damage. However, it remains unclear whether initiating therapy at the time of biochemical progression (BP) improves the outcomes compared with initiating therapy at the clinical progression (CP) stage. Here, we retrospectively assessed 1347 patients with relapsed MM. Most progressions were BP (60.4%); 39.6% had CP. The most prevalent symptoms at relapse were new or evolving bone disease (80.9%), anemia (38.0%), and renal failure (12.7%). Patients with BP had longer median time from second-line treatment to the next treatment compared with patients who had CP (17.0 vs 9.6 months; P &lt; .001) as well as longer median overall survival from first relapse (59.4 vs 26.2 months; P &lt; .001). Male sex (odds ratio [OR], 1.49; 95% confidence interval [CI], 1.02-2.18; P = .04), plasma cell labeling index ≥2% (OR, 1.58; 95% CI, 1.02-2.45; P = .04), and extramedullary disease at diagnosis (OR, 1.84; 95% CI, 1.08-3.13; P = .03) were associated with higher risk of CP, whereas very good partial remission or better had decreased risk of CP (OR, 0.62; 95% CI, 0.43-0.91; P = .02). To conclude, patients with CP have inferior postprogression outcomes compared with patients who have BP. Patients with deeper response to first-line therapy are less likely to develop CP. The presence of a specific CRAB (C, hypercalcemia; R, renal failure; A, anemia; B, bone disease) symptom at diagnosis predicts for the development of similar CRAB symptoms at relapse.

Abstract Introduction: There is evidence that lack of a social network is a link to inferior outcomes in cancer patients. Mayo clinic performs all its stem cell transplants for multiple myeloma patients as an outpatient. This requires a full-time chaperone or caregiver for the duration of the transplant. Patients who do not have a caregiver are hospitalized for the duration of the transplant. In this study we compared outcomes between patients hospitalized for the entire transplant and those who have a caregiver and are initially managed as an outpatient.Materials and methods: All patients with multiple myeloma transplanted at the Mayo Clinic in Rochester Minnesota between 1/1/2000 and 12/31/2019 were included for analysis. Patient had to have been transplanted within 12 months of the original diagnosis. The definition of inpatient transplantation was hospitalization prior to day 0 of transplantation for conditioning and continued hospitalization until evidence of neutrophil engraftment occurred.Results: There were 41 patients who were considered inpatient transplants and 2103 that were outpatient transplants. The patients were well balanced for age, sex, serum creatinine, and international stage at diagnosis. For inpatient transplants the median days in the hospital was 21 (interquartile range 18 to 28). For outpatient transplants the median number of days in the hospital was 0 (interquartile range 0 to 6). Relapse free survival was not significantly different between the 2 groups, but overall survival was 95 versus 58 months favoring those that had transplantation as an outpatient (p=.0008). Conclusion: There appears to be in association between myeloma patients that lack a caregiver and require inpatient stem cell transplantation and overall survival.