Ailawadhi, Sikander

PURPOSE: The benefit of routine pre-emptive screening for severe acute respiratory syndrome coronavirus 2 infections in patients with cancer before cancer-directed therapies is unclear. Herein, we characterize the outcomes of a cohort of patients with cancer who were diagnosed with COVID-19 by routine screening (RS) in comparison with those diagnosed on the basis of clinical suspicion or exposure history (nonroutine screening [NRS]). METHODS: A multisite prospective observational study was conducted at three major and five satellite campuses of the Mayo Clinic Cancer Center between March 18 and July 31, 2020. The primary outcome was COVID-19–related hospital admission. Secondary outcomes included intensive care unit admissions and all-cause mortality. RESULTS: Five thousand four hundred fifty-two patients underwent RS in the outpatient setting only, and 44 (0.81%) were diagnosed with COVID-19. RS detected 19 additional patients from the scheduled inpatient admissions for surgical or interventional procedures or inpatient chemotherapy. One hundred sixty-one patients were diagnosed with COVID-19 on the basis of NRS. COVID-19–related hospitalization rate (17.5% v 26.7%; P = .14), intensive care unit admission (1.6% v 5.6%; P = .19), and mortality (4.8% v 3.7%; P = .72) were not significantly different between the RS and NRS groups. In the multivariable analysis, age ≥ 60 years (odds ratio, 4.4; P = .023) and an absolute lymphocyte count ≤ 1.4 × 109/L (odds ratio, 9.2; P = .002) were independent predictors of COVID-19–related hospital admission. CONCLUSION: The COVID-19 positivity rate was low on the basis of RS. Comparing the hospital admission and mortality outcomes with the NRS cohort, there were no significant differences. The value of routine pre-emptive screening of asymptomatic patients with cancer for COVID-19 remains low.

Introduction Carfilzomib dosing as a single agent or in combination with dexamethasone (Kd) has evolved from the initial 27 mg/m 2 twice-weekly (legacy dose), to more recently approved doses of 56 mg/m 2 twice-weekly and 70 mg/m 2 once-weekly (optimized doses). The objective of this study was to evaluate the overall survival (OS), and time to next treatment (TTNT) among multiple myeloma patients treated with Kd optimized vs legacy doses. Methods A retrospective analysis of patients receiving Kd between 01/01/2013–07/31/2017 was conducted using IQVIA’s oncology electronic medical records database. Kd dose was estimated based on body surface area. OS was measured from the Kd-initiation date until death. TTNT was defined as the time from Kd-initiation until the start of subsequent treatment. Kaplan-Meier analysis and Cox models were used to evaluate OS and TTNT. Results Of the 1,469 patients evaluated, 129 (8.8%) received optimized dose and 1,340 (91.2%) received legacy dose. Risk of mortality was 64% lower for patients receiving the optimized doses (HR: 0.36, 95% CI: 0.178–0.745). Patients receiving the optimized doses had significantly longer TTNT compared to patients receiving the legacy dose (median TTNT: 17.5 months [95% CI: 14.8-NE] and 13.2 months, [95% CI: 12.4–14.4], respectively; p = 0.023), and 33% lower risk of progressing to the subsequent treatment (HR: 0.67, 95% CI: 0.48–0.93). Conclusions Patient outcomes could be improved if eligible MM patients are treated with the optimized, recently approved Kd doses (56 mg/m 2 twice-weekly and 70 mg/m 2 once-weekly).

7561 Background: Phospholipid ethers (PLE) provide a novel mechanism to specifically target tumor cells leveraging high lipid raft content in their cell membranes. PLE/phospholipid drug conjugates are specifically designed to have high affinity to lipid rafts which upon binding results in trans-membrane flipping with the ability to deliver an attached warhead directly to the cytosol. CLR 131 (I-131-CLR1404) is a novel PLE molecule armed with I-131 resulting in targeted tumor cell radiotherapy which is being examined in relapsed or refractory WM through an open-label, Phase 2 trial, CLOVER-1 (NCT02952508). Methods: The primary objective of this study is to determine the efficacy and safety of CLR 131 in select B-cell malignancies. Eligibility criteria for WM pts include receipt of at least 2 prior treatment regimens unless ineligible to receive standard agents and have measurable disease: either IgM or extramedullary disease. CLR 131 is administered in up to 4 IV infusions (15-20 min) over 3 months. Adverse events (AEs) are graded by NCI-CTCAE v4.03; responses are assessed by the VIth WM Criteria for Response Assessment [Owen 2013]. Results: 6 pts with WM were enrolled in the study with data current as of 8 Jan 2021. The median age was 69 (range 54-81) with 4 females and 2 males who had a median of 2 prior regimens (range 1-5) and received a mean total body dose of 92.76 mCi CLR 131. 3 of 6 patients were MYD88 wild type (WT) of which 2 were dual WT (MYD88 WT & CXCR4 WT). The overall response rate (ORR) was 100% and the major response rate (MRR) was 83%, including 1 pt with a CR, 4 PR, and 1 MR. For those pts who were dual WT, the MRR was 100% and 1 pt who was MYD88 WT (CXCR4 is unknown) had a complete response. The median time to initial response was 48 days. Median duration of response (DOR) and treatment free remission (TFR) have not been reached; ongoing mean DOR is 335 days and mean TFR is 384 days. 100% of MYD88 WT patients have exceeded 6.5 months of follow up with average TFR of 18.1 months. The primary treatment emergent AEs in pts with WM included fatigue and cytopenias, in line with prior experience with CLR 131 in other B-cell malignancies. The most commonly observed cytopenias included Grade 3 or 4 thrombocytopenia (100%), neutropenia (83%), anaemia (66%) and decreased white blood cell count (33%). Of note, no cases of bleeding or febrile neutropenia were observed. Conclusions: Initial results for CLR 131 show efficacy across multiple WM patient genotypes including dual WT patients with durable DOR and TFR after 2 to 4 infusions. CLR 131 represents a novel and promising approach to the treatment of MYD88 WT patients who have a historical median time to progression of 1.3 years. These encouraging data led to the pivotal global CLOVER-WaM trial (N=50) in WM patients who have failed or had a suboptimal response to a Bruton Tyrosine Kinase inhibitor. CLOVER-WaM is currently enrolling. Clinical trial information: NCT02952508.

7502 Background: The BCL-2i venetoclax is active in certain HMs but can increase the risk of tumor lysis syndrome (TLS), requiring a 5-week dose ramp-up for CLL patients. Cases of severe neutropenia with venetoclax treatment have also been reported. Lisaftoclax is a novel, potent, selective BCL-2i that is active against HMs and is under clinical development. Methods: This first-in-human global phase I dose study assessed the safety, PK, PD, efficacy, and MTD/RP2D of lisaftoclax in patients with R/R CLL and other HMs. Lisaftoclax was orally administered daily in a 28-day cycle. Patients with CLL or intermediate-high TLS risk were initiated on a daily ramp-up schedule until the assigned dose before the study cycles. Results: On January 7, 2021, 35 pts had been enrolled and treated with lisaftoclax at doses ranging from 20 to 1,200 mg, with a median (range) of 2 (1-13) prior lines of treatment, and had diagnoses of R/R CLL or SLL (n = 15), MM (n = 6), FL (n = 5), WM (n = 4), and either AML, MCL, DLBCL, MDS, or HCL (n = 1 each). No DLT has been observed, even though 1,200 mg was considered as the highest dose treated. The MTD has not been reached, and no laboratory or clinical TLS has been reported. Any grade TRAEs in > 10% of pts included neutropenia (22.9%) and anemia (17.1%; hematologic), and fatigue (28.6%), diarrhea (17.1%), and nausea (11.4%; nonhematologic). Grade >3 TRAEs were neutropenia (14.3%) and thrombocytopenia, leukopenia, lymphopenia, fatigue, and nausea (2.9% of pts each). In CLL/SLL pts, grade 3-4 TRAEs included neutropenia (13.3%) and thrombocytopenia (6.7%), which did not cause treatment-related discontinuation. In all, 12 of 35 pts (34.3%) had non-treatment-related SAEs, and only two pts experienced > 1 SAE. With a median (range) treatment of 7 (3-20) cycles, 12 of 14 evaluable R/R CLL/SLL pts achieved PR, for an ORR of 85.7% and a median (range) time to response of 3 (2-7) cycles. Absolute lymphocyte counts (ALCs) were reduced at lisaftoclax doses as low as 20 mg/day. The preliminary PK profile showed that exposures increased with lisaftoclax doses from 20 to 1,200 mg (average half-life: 4-5 hours). On BH3 profiling, lisaftoclax rapidly triggered changes in BCL-2 complex in CLL/SLL pt samples, which were consistent with rapid clinical reductions in ALCs. Conclusions: Lisaftoclax was well tolerated up to 1,200 mg/day. No TLS was observed, even with the daily ramp-up schedule. There were no significant new or unmanageable safety findings, and the ORR in R/R CLL/SLL pts was 85.7%. Grade 3-4 TRAEs were infrequent, even at dose levels of 800 mg and above. BCL-2i lisaftoclax offers a treatment alternative for patients with R/R CLL/SLL and other HMs, with a daily ramp-up schedule that may be more pt “user friendly” and a favorable preliminary safety profile. Internal study identifier APG2575-001. Clinical trial information: NCT03537482.

e18584 Background: Cancer progression rates following diagnosis are readily measured. However, the progression rate of cancer during the preclinical sojourn time is generally unobserved. Understanding the duration of preclinical stages (“dwell time”) would allow clinicians to better identify appropriate screening intervals for cancer. We therefore elicited estimates of progression rate during the preclinical sojourn time for a wide variety of malignancies from a panel of clinical experts. Methods: We used a validated consensus methodology (RAND/UCLA modified Delphi panel method) to elicit per-stage dwell time estimates for 20 solid cancers and lymphoma from experts. Eleven experienced oncologists (general and subspecialists) from community and academic centers reviewed literature on the natural history of disease and estimated in number of years (<1 to 9+ years) how long it would take each cancer to progress from the beginning of clinically detectable Stage I/II/III to the beginning of the next stage in untreated adults. Cancer histological subtypes were grouped and experts were asked to provide an overall rating. Ratings were completed before and after a discussion of areas of disagreement. Results: Expert estimates and range of dwell time for 21 cancer types are provided in Table. Prostate and thyroid cancer were estimated to be the slowest growing, taking approximately 7 and 5 years respectively to progress through Stage I (range 4-8), 5 years to progress through Stage II (range 3-7), and 3 and 4 (range 2-5) years respectively to progress through Stage III. Esophageal, lung, liver/intrahepatic bile-duct, gallbladder, and pancreatic cancers were estimated to progress quickly through all three stages (1-2 years per stage). Conclusions: These findings summarize practicing oncologists’ estimates of dwell time in preclinical disease. Experts agreed on dwell times although ranges were large and differences in cancer subtypes were not captured. Generally, estimates trend with published data on survival with treatment: cancers with higher survival (e.g., prostate, thyroid) were estimated to grow slower, while cancers with lower survival (e.g., pancreatic, liver/intrahepatic bile-duct, gallbladder) were estimated to grow faster. These estimates could be useful when determining screening intervals for these or any subset of these cancers. [Table: see text]

6594 Background: Patient reported financial hardship (FH) in cancer care is a growing challenge for patients, their caregivers and healthcare providers. As treatment costs escalate, it is imperative to develop effective strategies to proactively recognize and mitigate FH within oncology practice. Using automated processes to screen and refer patients to appropriate resources is a potential option. At Mayo Clinic, screening for FH involves using a single financial strain question ‘ How hard is it for you to pay for the very basics like food, housing, medical care, and heating?’ completed by all cancer patients annually as part of the Social Determinants of Health (SDOH) assessment. In this study, we describe the prevalence and predictors for FH (denoted by the answer ‘hard and very hard’) in our patient population. Methods: Patients receiving cancer care at the three Mayo Clinic sites (Minnesota, Arizona, and Florida) who completed the FH screen at least once were included in this study. Demographics (age, gender, race/ ethnicity, insurance, employment status, marital status, and zip code) and disease state data for included patients was extracted from the EMR and Mayo Clinic Cancer Registry. Disease state was categorized by type of cancer (hematological or solid malignancy) and cancer stage. Zip code was used to derive median income, rural/urban residence and distance from the cancer center. Multivariable logistic regression models were utilized to examine factors associated with FH. Results: The final study cohort included 31,969 patients with median age 66 years (IQR 57,73), 51% females, and 76% married. Race/ethnicity composition was 93% White, 3% Black, and 4% Hispanic. 52% of patients had Medicare and 43% had commercial insurance. Other notable factors included 48% retired, 41% working/ students, 76% married, and 72% urban residents. Median time from cancer diagnosis was 1.1 year (IQR 0.1, 3.8) and median income was $64,406 (IQR 53,067, 82,038). 31% of patients had hematological malignancies, 20% of the cancers for which staging information was available were metastatic. FH was reported by 4% (n = 1194) of the patients. A significantly higher likelihood of endorsing FH (p < 0.001 for all) was noted in Hispanic (OR 1.64), Black (OR 1.84), American Indian/Alaskan native (OR 2.02), below median income (OR 1.48), rural (OR 1.17), self-pay (OR 2.77), Medicaid (OR 2.29), Medicare (OR 1.43), unemployed/disabled (OR 2.39), single (OR 2.07), or divorced (OR 2.43) patients. Older age, being retired, and living farther from the cancer center were associated with significantly less likelihood of endorsing FH. Conclusions: Our study successfully leveraged the EMR to identify key sociodemographic groups more likely to report FH. An electronic trigger to flag such patients at high-risk of FH and proactively address FH is currently being developed.

Abstract Comparative data guiding initial therapy for Waldenström macroglobulinemia (WM), an infrequently encountered non‐Hodgkin lymphoma, are sparse. We evaluated three commonly used rituximab‐based frontline regimens: rituximab‐bendamustine (R‐Benda); dexamethasone, rituximab, cyclophosphamide (DRC); and bortezomib, dexamethasone, rituximab (BDR) in 220 treatment‐naïve patients with WM, seen at Mayo Clinic between November 1, 2000 and October 31, 2019. The median follow‐up was 4.5 (95%CI: 4–5) years. The R‐Benda cohort (n = 83) demonstrated superior overall response rate (ORR: 98%), in comparison to DRC (n = 92, ORR: 78%) or BDR (n = 45, ORR: 84%) cohorts, p = 0.003. Similarly, longer progression‐free survival (PFS) was evident with R‐Benda use [median 5.2 vs. 4.3 (DRC) and 1.8 years (BDR), p < 0.001]. The time‐to‐next therapy (TTNT) favored R‐Benda [median, not‐reached, 4.4 (DRC) and 2.6 years (BDR), p < 0.001). These endpoints were comparable between the DRC and BDR cohorts. Overall survival (OS) was similar across the three cohorts, p = 0.77. In a subset analysis of 142 patients genotyped for MYD88 L265P mutation, the ORR, PFS and TTNT were unaffected by the patients' MYD88 signature within each cohort. In conclusion, ORR, PFS and TTNT with R‐Benda are superior compared to DRC or BDR in treatment‐naïve patients with active WM. The patient outcomes with any one of these three regimens are unaffected by the MYD88 L265P mutation status.

Abstract OBJECTIVES: The impact of treatment modifications including replacement of alkylating agents based regimens and improvement in the practices of radiation oncology on the risk of secondary cancers (SCs) in Hodgkin's lymphoma (HL) survivors is unknown in the United States (U.S.). This study analyzed the trends of secondary cancer risks among the survivors of HL in the U.S. METHODS: The HL patients diagnosed during 1973-2014 were identified from the Surveillance, Epidemiology and End results (SEER) database. Due to differences in the treatment practices in HL, the whole cohort was divided into three time-periods: 1973-1986, 1987-2000 and 2001-2014. We compared the risk of SCs in the HL patients with the risk expected in the U.S. general population over the three study periods. RESULTS: With a follow-up of 23,864 HL survivors for 284,730 person-years (PY), 3260 secondary cancers were diagnosed, with standardized incidence ratio (SIR) of 1.97 (95% CI, 1.9-2.04) which resulted in 56.56 excess cancers per 10,000 person-years. SIR for any SCs in women (SIR 2.17; 95% CI 2.06-2.28) was significantly higher than in the men (SIR 1.84; 95% CI 1.75-1.92). The highest SIRs were observed for AML (SIR, 9.9; 95%CI, 8.3-11.9), NHL (SIR, 5.8; 95% CI, 5.3-6.4) and salivary gland tumors (SIR, 6.04; 95% CI, 4-8.8) while lung cancer (23.6%) and breast cancer (27.4%) contributed most to the excess risk in males and females respectively. The SIR for any SCs was maximum in the period after 15 to 20 years from the diagnosis of HL and remained high for more than 20 years after the diagnosis of HL (SIR for ≥ 20 years, 2.34; 95% CI, 2.19 to 2.5). A statistically significant decrease in the overall SIRs of SCs was observed in HL patients diagnosed during 1987-2000 (SIR 1.82 95% CI 1.72-1.93) and 2001-2014 (SIR 1.66 95% CI 1.51-1.82) as compared to the patients diagnosed in 1973-1986 (SIR 2.24 95% CI 2.13-2.35). (Figure 1) The decline in the overall SIR was mostly due to decline in the digestive tract and breast cancers. The SIRs of most of the other solid tumors and hematological malignancies including individual risks for NHL and AML did not decrease in the more recent study periods. Moreover, the decline in the SIRs of solid tumors was noticed only in the patients age below 60 years old. The female patients diagnosed in the most recent period were at lower risk of developing breast cancers (SIR 0.56 95% CI 0.34-0.86) as compared to the general population. The decline in the risk for secondary cancers was observed only after 10 years from the diagnosis of HL. After making adjustments for age, gender and race, patients diagnosed during 1973-1986 were at 12% higher risk of developing SCs (HR 1.12 95% CI 1.03-1.23 p=0.01) as compared to the patients diagnosed during 1987-2000. The hazard ratio for developing SCs in the patients diagnosed during 2001-2014 was not different from the patients diagnosed during 1987-2000 (HR 1.02 95% CI 0.9-1.2 p=0.74). CONCLUSIONS: Although, the overall risk of secondary cancers in patients with Hodgkin's lymphoma has declined after the modifications in Hodgkin's lymphoma treatment, apart from the digestive tract and breast cancers the risk has not changed significantly at most of the individual sites. The risk of secondary cancers is still 70% higher than the general population and is maximum 15-20 years from the diagnosis of Hodgkin's lymphoma. Thus close follow up with active surveillance for secondary cancers is crucial for the long term survivors of Hodgkin's lymphoma. Disclosures Ailawadhi: Novartis: Consultancy, Honoraria; Pharmacyclics: Research Funding; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria.

Abstract Background:Racial disparities in multiple myeloma (MM) outcomes are well established. Clinical characteristics and cytogenetic abnormalities dictate outcomes in MM but historically they have been mostly defined in White patients with paucity of information regarding racial-ethnic minorities. Hispanics are the fastest growing racial-ethnic subgroup in United States and have the worst overall survival (OS) in MM but differences in disease presentation among Hispanics compared to Whites, the historical control, are undefined. Methods: MM patients seen at Mayo Clinic in Florida (MCF) and Arizona (MCA) between 1/1/2000-06/15/2017 were included. Patient and disease characteristics including gender, age at diagnosis, bone marrow (BM) plasmacytosis, laboratory data [M spike, creatinine (Cr), beta-2-microglobulin (B2M), Hemoglobin (Hb), calcium (Ca)], MM subtype [IgG, IgA, light chain (LC), other], LC subtype (κ, λ, biclonal), presence of lytic bone lesions, disease stage (DS, ISS, R-ISS), mSMRT cytogenetic risk category, presence of individual cytogenetic mutations (deletions, translocations, gains, trisomy/hyperdiploidy) was collected. Comparisons between Hispanic study cohort characteristics and historical control were made by Chi-square, Fischer's exact and Signed rank tests, where applicable, using data from previous publications [Kyle et al, 2003 (n=1027) and Fonseca et al, 2003 (n=351)]. Patients with missing data on a certain clinical or disease feature were not included in the statistical analysis of that specific characteristic. Results: A total of 1705 MM patients were screened and 266 Hispanic patients seen at either site between the specified dates were identified for the analysis. These included equal number of males and females (n=133 each) with a median age of 58 years (range 25-87). IgG disease was seen in 52% with IgA and LC subtypes in 23% each. LC subtype was κ in 67%, λ in 31% and biclonal in 2% cases. Lytic and extramedullary disease were noted in 71% and 44% patients, respectively. DS and R-ISS stage at the time of MM diagnosis was not available in most patients while ISS stage among 150 patients showed stage 1, 2 and 3 in 48%, 28% and 24% patients, respectively. mSMART risk categories were present in 226 patients and included high, intermediate and standard risk in 12%, 11% and 77% patients, respectively. Of these 226 patients, cytogenetic disease prior to starting any MM treatment was available in 153 patients with similar risk category distribution. Median follow up for the whole Hispanic cohort was 38.6 months with a median OS 10.7 years (Figure 1). Comparison with historical control datasets which were 97% or greater comprised of White patients showed some significant differences for the Hispanic cohort including gender distribution, median age, BM plasmacytosis at the time of diagnosis, median Hb, Cr or M spike at presentation, light chain subtype, presence of lytic bone disease and certain cytogenetic alterations including t(4;14) and del13q/monosomy (Table 1). We did not note differences in high-risk cytogenetics between Hispanics and historical White controls. Conclusions: We report the first description of clinical and cytogenetic characteristics of Hispanic MM patients. The current and historical datasets that we have used are all from Mayo Clinic experience, thus making reasonable comparisons possible. We were able to confirm previous reports of demographic differences in Hispanics e.g., younger age at diagnosis. While some characteristics were significantly different, the clinical and cytogenetic differences we note do not clearly explain the inferior OS noted for Hispanics in population-based studies. Significant differences that we report warrant continued exploration in larger institutional and public databases in addition to a continued look into healthcare access and utilization. An ongoing collaborative analysis with data from Mayo Clinic, University of Miami and University of Southern California, Los Angeles is ongoing. Disclosures Fonseca: AMGEN: Consultancy; Jansen: Consultancy; Mayo Clinic & Dr Fonseca: Patents & Royalties: Prognostication of myeloma via FISH, ~$2000/year; Celgene Corporation: Consultancy, Research Funding; Merck: Consultancy; Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees; Bayer: Consultancy; Bristol-Myers Squibb: Consultancy; Takeda: Consultancy; Sanofi: Consultancy; Pharmacyclics: Consultancy; Novartis: Consultancy. Kelly: Pharmacyclics: Honoraria; Abbvie: Honoraria; Amgen: Honoraria; Jannsen: Honoraria. Sher: LAM Therapeutics, Inc: Research Funding. Ailawadhi: Pharmacyclics: Research Funding; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Novartis: Consultancy, Honoraria.

Abstract Background: It was once believed that African-American (AA) patients (pts) with multiple myeloma (MM) had more aggressive disease; however, recent studies suggest that undertreatment rather than biology is responsible for the poorer outcomes observed among AA pts. We recently reported that the utilization of stem cell transplants and bortezomib (BTZ) was 37% and 21% lower, respectively, among AA Medicare beneficiaries from 2000-2010 (Fiala & Wildes, Cancer, 2017). The data suggested that, had AA pts received these treatments at similar rates as their white counterparts there would have been no disparity in outcomes. As they did not, AA pts had a 10% increased risk for death. Lenalidomide (LEN), like BTZ, has become one of the primary treatments for MM since its approval in 2007. However, pts often incur significantly higher out of pocket costs on oral chemotherapies such as LEN compared to injectables like BTZ. Thus, we hypothesized that disparities in utilization of LEN would be greater than in BTZ. Methods: To test our hypothesis, all MM cases from 2007-2013 in the SEER-Medicare were reviewed along with corresponding claims through 2014. We excluded cases with incomplete records including those not enrolled in Medicare Part A, B, and D, and HMO enrollees. We also excluded cases where MM was diagnosed prior to age 65 and suspected cases of smoldering MM, pts who did not receive MM treatment and did not have diagnostic codes for CRAB criteria as previously described (Fiala, et al, under review). The presence or absence of claims for LEN and BTZ within 6 months following MM diagnosis was used to determine utilization. Multivariate logistic regression was performed to analyze the impact of race on LEN and BTZ utilization controlling for age at diagnosis, sex, year of diagnosis, Medicaid enrollment, and previously established algorithms of poor performance status [PS] indicators and Charlson Comorbidity Index [CCI] score. Results: 6,285 cases were included in the analysis. The median age at MM diagnosis was 76 years and 50% were female; 77% of cases were white, 16% were black, and 6% were another race. Overall, the utilization of LEN and BTZ during first-line treatment was 28% and 38%, respectively. In the multivariate model, race was not associated with LEN utilization, but BTZ utilization was reduced by 24% (aHR 0.76; 95% CI 0.65-0.90; p 0.0009) among AA pts. Overall, the models of LEN and BTZ were similar (Table 1). Advancing age, Medicaid enrollment and poor PS were associated with decreased utilization; more recent diagnosis increased utilization. CCI was associated with LEN but not BTZ utilization, sex with BTZ but not LEN. Discussion: We originally hypothesized that LEN utilization would be reduced among AA pts based on increased out-of-pocket costs. However, we and other researchers have shown that traditional access barriers such as insurance and income only account for about 25% of health disparities (Fiala & Wildes, Cancer, 2017). We now hypothesize LEN's oral administration may mitigate some other factors that have been shown to increase disparities such as the preferences and biases of pts and providers. For example, AA pts may prefer oral therapies to a greater extent than white pts. Or AA pts who may decline injectable chemotherapy due to distrust in the medical system may be more willing to accept an oral formulation, or providers who hold an unconscious bias may be more willing to offer one. An alternative explanation could be that AA pts, who tend to have more comorbidities and poorer overall health at MM presentation (Fiala, et al, 2015 ASH abstract 5618), were more likely to be candidates for LEN rather than other treatments. However, we do not believe this is the case as poor PS and increasing CCI were associated with decreased LEN utilization. Conclusions: AA race was associated with reduced utilization of BTZ but not LEN for first-line treatment of MM. These findings do not support our original hypothesis that LEN is associated with a greater disparity in utilization than BTZ due to the higher cost sharing involved with oral chemotherapies. Whether oral formulations mitigate other barriers to treatment such as the preferences and biases among pts and providers requires future study. Disclosures Ailawadhi: Pharmacyclics: Research Funding; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Novartis: Consultancy, Honoraria. Vij: Jazz: Honoraria; Konypharma: Honoraria; Celgene: Honoraria; Amgen: Honoraria, Research Funding; Takeda: Honoraria, Research Funding; Abbvie: Honoraria; Janssen: Honoraria; Bristol-Meyers-Squibb: Honoraria. Wildes: Carevive Systems Inc: Consultancy; Janssen: Consultancy.