National Cancer Institute Comorbidity Index Research Articles

Germline landscape of ovarian cancer across age groups: Spotlight on elderly patients.

10583 Background: Genetic testing is recommended for all patients with ovarian cancer (OC), particularly high-grade serous OC (HGSOC). However, emphasis is often placed on younger patients, and the germline landscape of elderly patients with HGSOC is not well studied. We sought to define germline pathogenic variants (gPV) in patients with HGSOC by age. Methods: Patients with HGSOC treated at our institution who underwent clinical tumor-normal sequencing from 1/1/2015 – 3/31/2022, inclusive of germline analysis of ≥76 genes were included. Clinical variables including age at diagnosis were collected. OC-related genes were defined as BRCA1, BRCA2, BRIP1, RAD51B, RAD51C, RAD51D, PALB2, ATM, MLH1, MSH2, MSH6,and PMS2. Logistic regression models were built to examine associations between presence of gPV and clinical variables. In patients with new gPV findings, rates of genetics follow-up were calculated. Results: Of 1,231 patients with HGSOC, median age at diagnosis was 63 years (range 33-93) with 163 (13%) patients diagnosed age ≤49, 739 (60%) diagnosed ages 50-69, and 329 (27%) diagnosed age ≥70 years. Age-related differences were observed in primary treatment (neoadjuvant vs. primary debulking), genetic ancestry, marital status, insurance type, and National Cancer Institute (NCI) comorbidity index, p<0.01.We observed gPV in 68/163 (42%) patients diagnosed age ≤49, 200/739 (27%) patients diagnosed ages 50-69, and 52/329 (16%) patients diagnosed age ≥70 years, p<0.001. OC-related gPV were found in 59/163 (36%) patients diagnosed age ≤49, 132/739 (18%) patients diagnosed ages 50-69, and 26/329 (7.9%) patients diagnosed age ≥70 years, p<0.001. Age was associated with gPV in univariate and multivariable (MV) models, even after adjustment for genetic ancestry and NCI comorbidity index. Compared to patients diagnosed ages 50-69 years, those diagnosed age ≥70 were less likely to have gPV (OR 0.58 95% CI 0.38-0.86) and those diagnosed at age ≤49 were more likely to have a gPV (OR 1.78 95% CI 1.18-2.68) in MV models. Among the 67 patients diagnosed age ≥80 years, 7 (10%) had gPV with only 2/7 in OC-related gPV ( BRCA2and PALB2) and the rest being of low/recessive/uncertain penetrance (N=1 FANCC,N=2 APC,N=1 BLM,N=1 CHEK2).In contrast, in the 21 patients diagnosed age ≤39 years, 12 (57%) had gPV with 2 patients having 2 gPV. All 21 patients had gPV in OC-related genes with 1 patient having both a BRCA1 and BRCA2 gPV and another having a BRCA1 and ERCC3 gPV. No differences in genetics follow-up were observed by age group in those with new gPV with 65% of patients diagnosed age ≥70 years having genetics follow-up for a new gPV. Conclusions: Although gPV vary by age in those with HGSOC with highest rates in those diagnosed younger than 50 years, rates are high (≥10%) with good genetics follow-up in all age groups. Our findings support genetic testing in all patients with EOC regardless of age given implications for treatment and family members.

Patterns of chemotherapy use with primary radiotherapy for localized bladder cancer in patients 65 or older.

Bladder preservation with concurrent chemoradiotherapy after maximum transurethral resection of bladder tumor is an alternative to radical cystectomy in select patients with muscle invasive bladder cancer (MIBC). Concurrent administration of radio-sensitizing chemotherapy and radiation therapy (RT) has been shown to have superior disease control compared with RT alone and can often be administered with modest added toxicity. We sought to describe national patterns of chemotherapy use. The linked surveillance, epidemiology, and end results (SEER)-Medicare database was used to identify patients with cT2-4, N0/X, M0/X BC who received radiation between 2004 and 2018. Data on demographics, clinicopathologic factors, therapy and outcomes were extracted. Concurrent utilization of chemotherapy with RT was also identified (CRT). Multivariate logistic regression (MVA) models were used to explore factors associated with receipt of chemotherapy and overall survival (OS). 2190 patients met inclusion criteria. Of these, 850 (38.8%) received no chemotherapy. Among those receiving chemotherapy, the most frequent regimens were single agent carboplatin, cisplatin, or gemcitabine. Factors that were independently associated with decreased likelihood of chemotherapy use were increasing age (OR 0.93, CI 0.92 - 0.95), Hispanic race (compared with White, OR 0.62, CI 0.39 - 0.99), cT3 or T4 (compared with cT2, OR 0.70, CI 0.55 - 0.90), and lower National Cancer Institute comorbidity index (OR 0.60, CI 0.51 - 0.70) (p < 0.05). Variables independently associated with increased likelihood of receipt of chemotherapy were married status (OR 1.28, CI 1.06 - 1.54), higher socioeconomic status (OR 1.31, CI 1.06 - 1.64), and later year of diagnosis (OR 1.09, CI 1.06 - 1.12). Receipt of concurrent chemotherapy with RT was associated with superior OS compared with RT alone. Over a third of patients >/65 years old receiving curative-intent RT for MIBC do not receive concurrent chemotherapy. Considering the improvement in oncologic outcomes with CRT over RT alone and more options, such as low dose gemcitabine which can be administered with modest toxicity, efforts are needed to identify barriers to utilization and increase the use of radio-sensitizing chemotherapy.

Abstract PO3-16-08: Real-World Treatment Patterns in Elderly Patients with HER2-Negative Early Breast Cancer

Abstract Background: As the treatment landscape of human epidermal growth factor receptor 2-negative (HER2–) early breast cancer (BC) evolves, an understanding of treatments given in real-world settings to elderly patients with HER2– early BC is needed to gain insight into the potential unmet needs of this population for whom clinical data are limited. This study described demographics, clinical characteristics, and neoadjuvant and adjuvant treatment patterns in elderly patients with HER2– early BC in the United States. Methods: This retrospective study used SEER-Medicare data (2010–2019) to identify patients aged ≥66 years with HER2– early (Stage I–III) BC receiving primary surgery. Patient characteristics were evaluated at primary surgery or at BC diagnosis. Neoadjuvant and adjuvant therapies were defined as any National Comprehensive Cancer Network-recommended regimens received between BC diagnosis and primary surgery, and during the 180-day period following primary surgery, respectively. Patient characteristics were described using means and standard deviations (SDs) for continuous characteristics, and frequencies and proportions for categorical characteristics. Neoadjuvant and adjuvant therapies were summarized using frequencies and proportions. All analyses were conducted for the overall population and stratified by breast cancer subtype (hormone receptor-positive [HR+]/HER2– vs. triple negative BC [TNBC]) and stage at diagnosis (Stage I vs. Stage II/III). Results: Of 28,655 eligible patients, 25,899 (90.4%) had HR+/HER2– BC and 2,756 (9.6%) had TNBC; 17,961 (62.7%) had Stage I BC and 10,694 (37.3%) had Stage II/III BC. Mean (SD) age at diagnosis was 75.8 (6.4) years, mean (SD) National Cancer Institute comorbidity index was 1.9 (2.1), and 23.7% received single or multi-gene testing for a breast cancer gene 1 and/or 2 (BRCA1/2) mutation (HR+/HER2– BC: 24.6%; TNBC: 15.5%), with most (86.3%) testing occurring after primary surgery. Relative to HR+/HER2– BC patients, TNBC patients were less likely to present with Stage I disease (46.7% vs. 64.4%), had a larger mean tumor size at diagnosis (2.6 cm vs. 1.9 cm), and higher-grade tumors (Grade III or IV: 70.6% vs. 14.6%). TNBC patients were also more likely to receive neoadjuvant chemotherapy (90.9% vs. 35.3%) and adjuvant radiation therapy (81.2% vs. 66.4%) than HR+/HER2– BC patients (Table 1). By BC stage, neoadjuvant therapy was more common among Stage II/III patients relative to Stage I patients (12.3% vs. 2.7%), with most (90.4%) neoadjuvant chemotherapy use observed among Stage II/III patients. Adjuvant therapy use was similar between Stage I and Stage II/III patients (87.4% vs. 88.1%) and the most common adjuvant therapies across both subgroups were endocrine therapy (85.2% vs. 82.2%) and radiation therapy (68.5% vs. 66.1%). Conclusion: In elderly patients with HER2– early BC, treatment with adjuvant therapy was common, while neoadjuvant therapy was limited. Moreover, one in four HER2– early BC patients were tested for a BRCA1/2 mutation in real-world clinical practice. Our findings highlight the need for a better understanding of the role of increased and timely BRCA1/2 testing to inform optimal treatment strategies across neoadjuvant and adjuvant settings in this population. Table 1. Treatment Patterns Among Patients with TNBC and HR+/HER2– Early Breast Cancer Citation Format: Jagadeswara Earla, Allison Kurian, Kalé Kponee-Shovein, Ambika Satija, Yan Song, Nathaniel Downes, Malena Mahendran, Qi Hua, Arun Kumar, Jaime Mejia. Real-World Treatment Patterns in Elderly Patients with HER2-Negative Early Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-16-08.

Abstract PO1-17-05: Real-world effectiveness of palbociclib plus aromatase inhibitors (AI) in metastatic breast cancer patients with cardiovascular diseases

Abstract Background Breast cancer survivors are at risk for mortality from cardiovascular diseases (CVD). CVD and their treatments can impact breast cancer treatment selection and clinical outcomes. A cyclin dependent kinase 4/6 inhibitor (CDK4/6i) combined with endocrine therapy (ET) is more effective than ET alone for hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2) metastatic breast cancer (MBC). CDK4/6i plus ET is now the standard of care in the first-line setting for HR+/HER2 MBC. However, data on the effectiveness of CDK4/6i in MBC patients with CVD are limited. We compared overall survival (OS) and real-world progression-free survival (rwPFS) of palbociclib plus AI (PAL+AI) vs AI alone in HR+/HER2 MBC patients with CVD in routine US clinical practices. Methods The Flatiron Health longitudinal database contains electronic health records from &amp;gt;280 cancer clinics, representing &amp;gt;3 million actively treated cancer patients in the US. Using the Flatiron database, we conducted a retrospective analysis of 469 patients with HR+/HER2 MBC and CVD who started PAL+AI or AI as first-line therapy between February 2015 and March 2020. CVD prior to the initiation of PAL+AI or AI were identified based on their definitions within the National Cancer Institute-Comorbidity Index (NCI-CI), including myocardial infarction, congestive heart failure, peripheral vascular diseases, and cerebrovascular diseases. Patients were assessed from start of PAL+AI or AI to September 30, 2020 (data cutoff date), death, or last visit, whichever came first. OS was defined as months from start of PAL+AI or AI to death. rwPFS was defined as months from start of PAL+AI or AI to death or disease progression, evaluated based on clinical assessment or radiographic scan/tissue biopsy. Stabilized inverse probability treatment weighting (sIPTW) as primary analysis was used to balance baseline demographics and clinical characteristics. Cox proportional-hazards models were used to estimate the relative effectiveness of PAL+AI vs AI alone. Results Of the 469 eligible patients, 160 (34.1%) were treated with PAL+AI and 309 (65.9%) were treated with AI alone. Compared with AI-alone patients, those treated with PAL+AI were younger and were more likely to have de novo MBC, ≥2 metastatic sites, and lung/liver involvement. After sIPTW, patient characteristics were generally balanced. After sIPTW, median OS (95% confidence interval [CI]) was 40.7 months (30.956.0) in PAL+AI patients and 26.5 months (23.337.3) in AI patients (hazard ratio [HR]=0.732, 95% CI=0.5370.997, p=0.0476). Median rwPFS (95% CI) was 20.0 months (11.7–27.5) in PAL+AI patients and 12.5 months (9.718.3) in AI patients (HR=0.679, 95% CI=0.5120.900, p=0.0070). Consistent results were observed with multivariate Cox proportional-hazards models as sensitivity analysis. See Table for baseline patient characteristics and outcome results. Conclusions First-line PAL in combination with AI is associated with prolonged OS and rwPFS in patients with HR+/HER2 MBC and CVD in a real-world setting compared with AI alone. Further studies with larger cohorts and comprehensive assessments of comorbidities are needed to provide additional evidence of outcomes and safety of CDK4/6i plus AI for MBC patients with various comorbid conditions in routine clinical practice. Citation Format: Adam Brufsky, Xianchen Liu, Benjamin Li, Lynn McRoy, Connie Chen, Doris Makari, Rachel Layman, Hope Rugo. Real-world effectiveness of palbociclib plus aromatase inhibitors (AI) in metastatic breast cancer patients with cardiovascular diseases [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-17-05.

Clinical outcomes of patients with newly diagnosed large B-cell lymphoma in a safety-net hospital system

AbstractReal-world outcome data for patients with large B-cell lymphomas (LBCLs) who are uninsured or have socioeconomic barriers to care are limited. We performed a retrospective cohort study of patients with newly diagnosed LBCL treated in a large safety-net hospital system. Between January 2011 and June 2022, 496 patients aged >18 years were diagnosed with LBCL at Harris Health System, Houston, Texas. The median age was 53 years, 75% were uninsured, and 81% were in the most disadvantaged Area Deprivation Index national quartiles. Most (69%) had stage III/IV disease, 44% had poor-risk disease by the Revised International Prognostic Index (R-IPI), and 17% had a history of HIV infection. The median diagnosis-to-treatment interval was 17 days. The median follow-up time was 53.5 months. Among 464 evaluable patients, 66% achieved a complete response, and 11% had a partial response. Of 48 patients, 26 (54%) eligible for cell therapies received them. At 5 years, event-free and overall survival (OS) rates were 57% and 68%, respectively. Factors that affected OS included Hispanic ethnicity (hazard ratio [HR], 0.70; P = .027), R-IPI (HR, 4.67 for poor vs very good risk; P < .001), National Cancer Institute Comorbidity Index (HR, 1.53 per unit increment; P = .003), hemoglobin (HR, 0.89 per unit increment; P = .002), and International Normalized Ratio (HR, 2.17 per unit increment; P = .007). Insurance status was not associated with differences in OS. In our safety-net health system with robust financial assistance programs and limited access to cell therapies, uninsured status was not associated with inferior outcomes. Addressing barriers to care may improve outcomes in other settings.

Optimal number of cycles of bendamustine as initial chemoimmunotherapy for older patients with follicular lymphoma

AbstractBendamustine is among the most commonly used chemoimmunotherapies for patients with follicular lymphoma (FL). It is typically delivered with a goal regimen consisting of 6 cycles, but it is possible that treatment goals could be achieved with fewer cycles, particularly in older patients. We used data from the National Cancer Institute (NCI) linkage between Surveillance, Epidemiology, and End Results program and Medicare claims to evaluate the overall survival of patients with FL receiving 3 to 4 vs 5 to 6 cycles of bendamustine. Patients receiving 1 to 2 cycles of bendamustine chemotherapy were not included. Patients receiving 5 to 6 cycles of bendamustine were significantly younger (mean age, 75.0 vs 76.2 years; P < .01) and had fewer comorbidities by the NCI comorbidity index (mean score, 1.7 vs 2.0; P = .05) than those receiving 3 to 4 cycles of bendamustine, and on univariate analysis exhibited significantly lower risk of death (hazard ratio [HR], 0.75; 95% confidence interval [CI], 0.57-0.98; P = .04). However, multivariate analysis controlling for age and comorbidity did not reveal a significant association between overall survival and number of cycles of bendamustine (HR, 0.87; 95% CI, 0.66-1.15; P = .33). Limitations inherent to use of data such as these for causal inference are acknowledged. Nonetheless, these analyses suggest some older patients with FL achieve satisfactory survival outcomes even with lesser bendamustine exposure, and future efforts to prospectively identify such patients are warranted.

Long-term multimorbidity trajectories in older adults: The role of cancer, demographics, and health behaviors.

Multimorbidity is associated with premature mortality and excess health care costs. The burden of multimorbidity is highest among patients with cancer, yet trends and determinants of multimorbidity over time are poorly understood. Via Medicare claims linked to Cancer Prevention Study II data, group-based trajectory modeling was used to compare National Cancer Institute comorbidity index score trends for cancer survivors and older adults without a cancer history. Among cancer survivors, multinomial logistic regression analyses evaluated associations between demographics, health behaviors, and comorbidity trajectories. In 82,754 participants (mean age, 71.6 years [SD,5.1 years]; 56.9% female), cancer survivors (n=11,265) were more likely than older adults without a cancer history to experience the riskiest comorbidity trajectories: (1) steady, high comorbidity scores (remain high; odds ratio [OR],1.36; 95% CI, 1.29-1.45), and (2) high scores that increased over time (start high and increase; OR,1.51; 95% CI, 1.38-1.65). Cancer survivors who were physically active postdiagnosis were less likely to fall into these two trajectories (OR,0.73; 95% CI, 0.64-0.84, remain high; OR,0.42; 95% CI, 0.33-0.53, start high and increase) compared to inactive survivors. Cancer survivors with obesity were more likely to have a trajectory that started high and increased (OR,2.83; 95% CI, 2.32-3.45 vs. normal weight), although being physically active offset some obesity-related risk. Cancer survivors who smoked postdiagnosis were also six times more likely to have trajectories that started high and increased (OR,6.86; 95% CI, 4.41-10.66 vs. never smokers). Older cancer survivors are more likely to have multiple comorbidities accumulated at a faster pace than older adults without a history of cancer. Weight management, physical activity, and smoking avoidance postdiagnosis may attenuate that trend.

Epidemiology of Cancer-Associated Venous Thromboembolism in Patients With Solid and Hematologic Neoplasms in the Veterans Affairs Health Care System

Identifying changes in epidemiologic patterns of the incidence and risk of cancer-associated thrombosis (CAT), particularly with evolving cancer-directed therapy, is essential for risk stratification. To assess the incidence of CAT over time and to determine pertinent patient-specific, cancer-specific, and treatment-specific factors associated with its risk. This longitudinal, retrospective cohort study was conducted from 2006 to 2021. Duration of follow-up was from the date of diagnosis until first venous thromboembolism (VTE) event, death, loss of follow-up (defined as a 90-day gap without clinical encounters), or administrative censoring on April 1, 2022. The study took place within the US Department of Veterans Affairs national health care system. Patients with newly diagnosed invasive solid tumors and hematologic neoplasms were included in the study. Data were analyzed from December 2022 to February 2023. Newly diagnosed invasive solid tumors and hematologic neoplasms. Incidence of VTE was assessed using a combination of International Classification of Diseases, Ninth Revision, Clinical Modification and International Statistical Classification of Diseases, Tenth Revision, Clinical Modification and natural language processing confirmed outcomes. Cumulative incidence competing risk functions were used to estimate incidence of CAT. Multivariable Cox regression models were built to assess the association of baseline variables with CAT. Pertinent patient variables included demographics, region, rurality, area deprivation index, National Cancer Institute comorbidity index, cancer type, staging, first-line systemic treatment within 3 months (time-varying covariate), and other factors that could be associated with the risk of VTE. A total of 434 203 patients (420 244 men [96.8%]; median [IQR] age, 67 [62-74] years; 7414 Asian or Pacific Islander patients [1.7%]; 20 193 Hispanic patients [4.7%]; 89 371 non-Hispanic Black patients [20.6%]; 313 157 non-Hispanic White patients [72.1%]) met the inclusion criteria. Overall incidence of CAT at 12 months was 4.5%, with yearly trends ranging stably from 4.2% to 4.7%. The risk of VTE was associated with cancer type and stage. In addition to confirming well-known risk distribution among patients with solid tumors, a higher risk of VTE was observed among patients with aggressive lymphoid neoplasms compared with patients with indolent lymphoid or myeloid hematologic neoplasms. Compared with no treatment, patients receiving first-line chemotherapy (hazard ratio [HR], 1.44; 95% CI, 1.40-1.49) and immune checkpoint inhibitors (HR, 1.49; 95% CI, 1.22-1.82) had a higher adjusted relative risk than patients receiving targeted therapy (HR, 1.21; 95% CI, 1.13-1.30) or endocrine therapy (HR, 1.20; 95% CI, 1.12-1.28). Finally, adjusted VTE risk was significantly higher among Non-Hispanic Black patients (HR, 1.23; 95% CI, 1.19-1.27) and significantly lower in Asian or Pacific Islander patients (HR, 0.84; 95% CI, 0.76-0.93) compared with Non-Hispanic White patients. In this cohort study of patients with cancer, a high incidence of VTE was observed, with yearly trends that remained stable over the 16-year study period. Both novel and known factors associated with the risk of CAT were identified, providing valuable and applicable insights in this current treatment landscape.

Venous thromboembolism risk in cancer patients receiving first-line immune checkpoint inhibitor versus chemotherapy.

It remains unclear if immune checkpoint inhibitor (ICI) therapy is associated with higher rate of venous thromboembolism (VTE) compared with cytotoxic chemotherapy (chemo) in patients with comparable cancer type, staging, and comorbidities. Using the national Veterans Affairs healthcare system database from 2016 to 2021, we performed a propensity score (PS)-weighted retrospective cohort study to compare the incidence of VTE in patients with selected stage III/IV cancer receiving first-line ICI versus chemo. The PS model utilized overlap weights to balance age, sex, race, treatment year, VTE history, paralysis/immobilization, prolonged hospitalization, cancer type, staging, time between diagnosis and treatment, and National Cancer Institute comorbidity index. Weighted Cox regressions with robust standard error were used to assess the hazard ratio (HR) and 95% confidence interval (CI). We found that among comparable advanced cancers, first-line ICI (n = 1823) and first-line chemo (n = 6345) had similar rates of VTE (8.49% for ICI and 8.36% for chemo at 6 months). The weighted HR was 1.06 (95% CI 0.88-1.26) for ICI versus chemo. In a subgroup analysis restricted to lung cancers, first-line ICI/chemo (n = 828), ICI monotherapy (n = 428), and chemo monotherapy (n = 4371) had similar rates of VTE (9.60% for ICI/chemo, 10.04% for ICI, and 8.91% for chemo at 6 months). The weighted HR was 1.05 (95% CI 0.77-1.42) for ICI versus chemo, and 1.08 (95% CI 0.83-1.42) for ICI/chemo versus chemo. In conclusion, ICI as a systemic therapy has a similarly elevated risk as cytotoxic chemo for VTE occurrence in cancer patients. This finding can inform future prospective studies exploring thromboprophylaxis strategies.

Healthcare Costs for Medicare Patients With Hepatocellular Carcinoma in the United States

Hepatocellular carcinoma (HCC) has an increasing mortality in the United States and is a leading cause of morbidity and mortality in patients with cirrhosis. We aimed to estimate the financial burden related to HCC in a large nationally representative United States cohort. We used the Surveillance, Epidemiology, and End Results program (SEER)-Medicare database to identify 4525 adult patients who were diagnosed with HCC between 2011 and 2015. We generated a 1:1 propensity score-matched cohort of patients with cirrhosis but no HCC as a comparator group to define incremental HCC-specific costs beyond costs related to underlying cirrhosis. Our main outcomes were patient liabilities and Medicare payments in the first year after HCC diagnosis. Compared with patients with cirrhosis, those with HCC had higher incremental patient liabilities (median+$7166; interquartile range, $2401-$16,099) and Medicare payments (+$50,110; interquartile range, $142,42-$136,239; P < .001 for both) in the first year after diagnosis. Patients with HCC had significantly higher inpatient, outpatient, and physician service costs compared with the matched cohort with cirrhosis (P < .001 for all). Patients with early-stage HCC had lower incremental patient liabilities (median, $4195 vs $8238; P < .001) and Medicare payments (median, $28,207 vs $59,509; P < .001) than those with larger tumor burden. In multivariable median regression analysis, incremental patient liabilities and Medicare payments were significantly associated with the National Cancer Institute comorbidity index, nonalcoholic fatty liver disease etiology, presence of ascites, and presence of hepatic encephalopathy. Patients with HCC suffer from cancer-related financial burden, highlighting a need for policy interventions and financial support systems.

Real-World Treatment Patterns, Healthcare Resource Use, and Costs Among Patients with Diffuse Large B-Cell Lymphoma: A Retrospective Analysis of US Claims Data

Introduction: Diffuse large B-cell lymphoma (DLBCL) is an aggressive form of non-Hodgkin's lymphoma with high economic burden and a strong pipeline of novel therapies. To better understand this rapidly evolving treatment landscape and current economic burden in DLBCL, this study describes real-world treatment patterns, healthcare resource use (HRU), and costs in DLBCL patients in the US, overall and by line of therapy (LOT). Methods: Optum Clinformatics claims data from October 2015 to June 2020 were used to identify adult patients with ≥2 diagnosis codes for DLBCL on ≥2 distinct dates within 12 months. The index date was defined as the date of the first observed DLBCL diagnosis. Continuous enrollment was required for ≥12 months pre-index (i.e., baseline period) and ≥1-month post-index. Patients with diagnosis codes for DLBCL or any other malignancy during baseline were excluded to increase the likelihood of capturing newly diagnosed patients. Demographic and clinical characteristics were assessed during baseline, and all-cause and DLBCL-related HRU (monthly incidence rates and 95% confidence intervals [CI]) and costs (per patient per month [PPPM]) were estimated from the index date to the earliest of end of either continuous enrollment or study period. A LOT algorithm was developed to identify lines of National Comprehensive Cancer Network (NCCN)-recommended systemic therapies, stem cell transplantation (SCT), and chimeric antigen receptor (CAR)-T therapies during the study period among a subset of patients with no claims for treatments of interest during the baseline period and ≥1 claim for treatment during the study period. HRU and costs were described during the first line (1L), second line (2L), and third and subsequent line (3L+) periods. Results: A total of 3,664 patients with DLBCL were included in the study and followed for a mean duration of 18 months post-DLBCL diagnosis. Patients were on average 70 years old, with 47% females, and 75% covered by Medicare. Mean National Cancer Institute Comorbidity Index (NCICI) was 2.2 and the most prevalent comorbidities were cardiovascular disease (32%), diabetes (29%), and chronic obstructive pulmonary disease (24%). On average, patients had 0.13 (95% CI: 0.13, 0.14) all-cause hospitalizations, 3.31 (3.29, 3.32) outpatient visits, 0.07 (0.06, 0.07) emergency room (ER) visits, and 0.15 (0.14, 0.15) other visits PPPM (Table 1). Almost all hospitalizations were DLBCL-related (0.12 PPPM), while outpatient, ER, and other visits were less driven by DLBCL-related visits (1.3, 0.01, and 0.04 visits PPPM respectively). Total all-cause costs were $19,686 PPPM and largely consisted of DLBCL-related medical costs ($16,803). Costs from DLBCL-related hospitalizations accounted for roughly half of the total all-cause costs ($10,704). A total of 2,234 patients (61%) were included for the treatment pattern analysis after applying additional inclusion criteria. Of those, 376 (17%) received a treatment of interest in the relapsed/refractory setting. Rituximab, cyclophosphamide, hydroxydaunorubicin hydrochloride, vincristine, and prednisone (R-CHOP) was the most common treatment in 1L (50%), followed by CHOP (29%) (Table 2). In the 2L setting, R-CHOP (15%), bendamustine-based therapies (14%), and SCT (13%) were the most common regimens. Bendamustine-based therapies (21%), gemcitabine-based regimens (13%), lenalidomide-based therapies (11%), and CAR-T therapy (11%) were commonly used in 3L. Mean treatment duration decreased with increasing lines of therapy (111 days for 1L, 98 days for 2L, and 81 days for 3L). All-cause and DLBCL-related HRU and costs tended to increase with increasing lines of therapy and were generally highest for 3L+ (Table 1). This was especially true for DLBCL-related hospitalization costs, which increased from $5,242 PPPM in 1L to $18,309 PPPM in 3L+ and accounted for increasingly larger proportions of total all-cause costs with increasing lines. Conclusions: This study summarizes the current treatment landscape and economic burden for DLBCL in the US. Results show that various therapies are being used for DLBCL management and quantify the high HRU and cost burden among patients with DLBCL, especially during later lines of therapy, highlighting an area of unmet need. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Economic Burden and Treatment Patterns Among Patients with Mantle Cell Lymphoma in the US: A Retrospective Claims Analysis

Introduction: Mantle cell lymphoma (MCL) is a rare, aggressive form of non-Hodgkin's lymphoma with relatively poor prognosis compared to other B-cell malignancies, high economic burden, and a changing treatment landscape with recent therapeutic advances. This study describes current treatment patterns, healthcare resource use (HRU), and costs in patients with MCL in the US. Methods: Adult patients with ≥2 diagnosis codes for MCL on ≥2 distinct dates within 12 months were identified in Optum Clinformatics claims data from 10/1/2015 to 3/31/2021. The first observed MCL diagnosis was considered the index date. The baseline period was defined as the 12 months of continuous enrollment pre-index; continuous enrollment was also required for ≥1 month post-index. Patients with diagnosis codes for MCL or other malignancies during baseline were excluded. The study period spanned from the index date till the earliest of either end of continuous enrollment or end of data availability. Demographic and clinical characteristics were described during the baseline period. All-cause and MCL-related HRU in terms of monthly incidence rates and 95% confidence intervals (CI) and per patient per month (PPPM) costs were described during the study period. A subset of patients meeting the following additional criteria were included in the treatment sequence analysis: no claims for treatments of interest during the baseline period and ≥1 claim for treatments during the study period. Treatments of interest included National Comprehensive Cancer Network (NCCN)-recommended systemic therapies, stem cell transplantation (SCT), and chimeric antigen receptor (CAR)-T therapy. An algorithm was developed to identify treatments in first line (1L), second line (2L), and third line (3L) during the study period. HRU and costs were described during the 1L, 2L, and third and subsequent line (3L+) periods. Results: The study included 696 patients with MCL, with a mean follow-up time of 22 months. Patients had a mean age of 71 years and were predominantly male (68%), with most having Medicare coverage (76%). The most common comorbidities during baseline were cardiovascular disease (29%), diabetes (27%), and chronic obstructive pulmonary disease (24%), with a mean National Cancer Institute Comorbidity Index (NCICI) of 1.9. During the study period, there were 0.13 (95% confidence interval: 0.12, 0.14) all-cause hospitalizations, 3.27 outpatient visits (3.24, 3.30), 0.06 (0.06, 0.07) emergency room (ER) visits, and 0.18 (0.18, 0.19) other visits PPPM (Table 1). Majority of hospitalizations were MCL-related (0.09 PPPM). MCL-related outpatient visits (1.57 PPPM), ER visits (0.01 PPPM), and other visits (0.06 PPPM) formed a lower proportion of all-cause visits. Patients had considerable total all-cause costs ($23,884 PPPM), almost all of which were medical costs ($22,717 PPPM). MCL-related medical costs contributed substantially to all-cause costs ($19,771 PPPM), largely due to MCL-related hospitalizations ($12,785 PPPM). 399 patients (57%) who received a treatment of interest during the study period were included in the treatment pattern analysis. Among these patients, 129 (32%) were observed to receive a treatment of interest in 2 or more lines. Bendamustine-based therapies were most used in 1L (51%), followed by SCT and rituximab monotherapy (11% each) (Table 2). Ibrutinib-based therapies were the most common in 2L (28%) and 3L (24%). Mean treatment duration decreased with increasing lines of therapy (173 days for 1L, 154 days for 2L, and 139 days for 3L). All-cause and MCL-related HRU and costs tended to increase with increasing lines of therapy (Table 1) - for example, hospitalization costs were twice as high in 3L+ ($24,314 PPPM for all-cause and $22,840 PPPM for MCL-related hospitalizations) than in 1L ($12,366 PPPM for all-cause and $11,162 PPPM for MCL-related hospitalizations). Conclusions: This study describes the contemporary treatment patterns and economic burden for MCL in the US. Results show that a range of treatments are used to manage MCL, with more recently approved therapies such as ibrutinib being used more commonly in later lines. This study also highlights high HRU and cost burden among patients with MCL, which increases with subsequent lines of therapy. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Cost to Treat Newly Diagnosed Patients with Paroxysmal Nocturnal Hemoglobinuria: A Retrospective Analysis

Background Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired hematologic disorder that renders affected patients’ red blood cells susceptible to premature destruction (i.e., hemolysis) and can lead to excess morbidity. Current pharmacological treatments for PNH include not only eculizumab, launched in 2007, but more recently approved treatments such as ravulizumab and pegcetacoplan. Even among patients treated with currently available therapies, suboptimal C5 inhibition or exacerbating factors such as infections may result in breakthrough hemolysis or other PNH-related complications. Given the evolving treatment landscape and challenges in treatment and diagnosis, it is unclear what the total and setting-specific costs and health care utilization are among patients newly diagnosed with PNH. Objectives To determine healthcare resource utilization and costs for newly diagnosed patients with PNH. Methods United States (US) adults with a new ICD-10 diagnosis of PNH (D59.5) from April 2016 to December 2020 identified in the OptumLabs claims data were included. The date of the first claim with a PNH diagnosis was defined as the index diagnosis date. Patients were required to have at least 6 months of continuous enrollment before the index diagnosis date to identify newly diagnosed patients and at least 6 months of continuous enrollment after the index diagnosis date for analysis. Comorbidity was measured with the National Cancer Institute (NCI) comorbidity index. All-cause healthcare resource utilization (HCRU), all-cause costs, PNH-related HCRU (defined as claims with an ICD-10 code of D59.5 in any position), and PNH-related costs were measured on a per-patient per-month (PPPM) basis for inpatient admissions, emergency department (ED) visits, office visits, and other outpatient visits for the 6-month follow-up period. The PPPM frequency of blood transfusions and utilization of bone marrow transplant were also assessed. The cost and HCRU results were age-weighted to be representative of the US population. Results Of the 749 patients with an ICD-10 diagnosis of PNH (D59.5) during the selected timeframe, 381 were newly diagnosed patients who met all inclusion criteria. In the unweighted sample, approximately half of the patients (50.9%) were female, with an average age of 61.3 (SD = 17.8), and the average NCI Comorbidity Index was 0.57 (SD = 0.65). Of the 381 patients in the weighted sample, 149 (39.1%) had an inpatient admission. Of these inpatient admissions, 86 (57.7%) were PNH-related. For patients with at least one inpatient admission, the mean length of stay (LOS) was 2.2 days (SD = 3.0) and the median LOS was 1.0 days. One hundred twenty-three (32.3%) PNH patients had an emergency department (ED) visit in the first 6 months after the index diagnosis, 12 of which (9.8%) were PNH-related. Nearly all patients had office visits (97.9%) or other outpatient visits (96.6%) in the 6-month follow up period. Blood transfusions occurred in 18.6% of the PNH population, while bone marrow transplant was relatively rare (result suppressed due to small cell size). (Table 1) The PPPM total cost for newly diagnosed patients was $10,480, or $125,758 per patient per year. Of these costs, 39.0% ($4,090 PPPM) were for pharmacy costs (including infusion costs), 33.9% ($3,551 PPPM) were for inpatient costs, 6.4% ($672 PPPM) were for office visits, 0.9% ($94 PPPM) were for ED visits, and 19.8% ($2,073 PPPM) were for other outpatient visits. The total PNH-related cost was $4,763 PPPM, accounting for 45% of the total cost. PNH-related pharmacy costs for eculizumab and ravulizumab, including administration, accounted for 60.2% ($2,868) of PNH-related costs (no pegcetacoplan use was observed since it was approved in 2021). PNH-related inpatient costs accounted for 28.0% ($1,333), office visits accounted for 3.6% ($172), and other outpatient visits accounted for 8.1% ($386) of total PNH-related costs. ED visits were rarely flagged with the PNH ICD-10 code, with less than 0.1% of PNH-related costs coming from the ED. (Figure 1) Conclusions Despite new treatment options available for PNH, HCRU and associated costs remain high with 39.1% of PNH patients having an inpatient visit in the first 6 months after diagnosis. Nearly one in five newly diagnosed PNH patients still require at least one blood transfusion in the follow-up period, signaling further unmet medical need in PNH. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Patient, Physician, Hospital Factors Associated With Readmission After Radical Cystectomy

Patient and clinical factors are the most commonly identified variables associated with hospital readmission after radical cystectomy, but other factors may be important drivers of outcomes, such as hospital and physician characteristics. This study investigates the contribution of patient, physician, and hospital factors in hospital readmission after radical cystectomy. This was a retrospective review of the Surveillance, Epidemiology, and End Results-Medicare database focusing on bladder cancer patients who underwent radical cystectomy between 2007 and 2016. Medicare claims were identified using International Statistical Classification of Diseases-9/-10 or Healthcare Common Procedure Coding System codes from Medicare Provider Analysis and Review or National Claims History claims, from which the annual hospital/physician volumes were calculated and classified as low, medium, and high. A multivariable analysis was done for 90-day readmission as the outcome using a multilevel model to explore the association between readmission and characteristics of patient, hospital, and physician. Models with random intercepts were constructed to consider the variation from hospital and physician. Of 3,530 patients, 1,291 (36.6%) were readmitted within 90 days of the index surgery. On multilevel multivariable analysis, factors significantly associated with readmission included continent urinary diversion (OR 1.55, 95% CI 1.21, 2.00), greater National Cancer Institute comorbidity index (2<4 vs 0-<2, OR 1.35, 95% CI 1.05, 1.75; 4+ vs 0-<2, OR 1.76, 95% CI 1.20, 2.58), American Joint Committee on Cancer stage (P = .04), and hospital region (P = .05). Neither hospital volume, physician volume, teaching hospital status, nor National Cancer Institute center designation was associated with hospital readmission. The main source of variation was determined to be the patient factors (95.89%), followed by the physician (1.43%), and then hospital (2.68%) factors. Patient-specific factors are the most important in impacting the odds of readmission after radical cystectomy, while hospital and physician factors contribute minimally to this outcome.

Risk of non-colorectal cancer-related death in elderly patients with the disease: A comparison of five preoperative risk assessment indices.

A considerable number of elderly patients with colorectal cancer (CRC) die of non-CRC-related causes. The Controlling Nutritional Status (CONUT) score, American Society of Anesthesiologists Physical Status classification, Charlson Comorbidity Index, National Institute on Aging, and National Cancer Institute Comorbidity Index, and Adult Comorbidity Evaluation-27 score are all known predictors of survival in patients with CRC. However, the utility of these indices for predicting non-CRC-related death in elderly CRC patients is not known. The study population comprised 364 patients aged 80 years or more who received curative resection for stage I-III CRC between 2000 and 2016. The association of each index with non-CRC-related death was compared by competing-risks analysis such as the cumulative incidence function and proportional subdistribution hazards regression analysis as well as time-dependent receiver-operating characteristic (ROC) analysis. There were 85 deaths (40 CRC-related and 45 non-CRC-related) during a median observation period of 53.2months. Cumulative incidence function analysis identified CONUT score as the most suitable for risk stratification for non-CRC-related death. In proportional subdistribution hazards regression, risk of non-CRC-related death increased significantly as CONUT score worsened (2/3/4 vs. 0/1, hazard ratio 1.73, 95% confidence interval [CI] 0.91-3.15; ≥5 vs. 2/3/4, hazard ratio 2.71, 95% CI 1.08-6.81). Time-dependent ROC curve analysis showed that CONUT score were consistently superior to other indices during the 5-year observation period. The majority of deaths in elderly patients with CRC were not CRC-related. CONUT score was the most useful predictor of non-CRC-related death in these patients.

Review of health care access duration among cancer patients at a large health plan.

e18758 Background: Cancer patients have unique, long-term health care needs and access to timely and affordable care is essential. Little is known about cancer patients’ propensity to leave their health plan during and after treatment. This study aimed to examine health care access duration among cancer survivors. Methods: Adult patients diagnosed with cancer between 11/1/2015 and 10/31/2016 were identified and followed until 11/1/2021. Control patients were identified as adults with no cancer diagnosis between 11/1/2015 and 11/1/2021. Patients with skin cancer were excluded due to limited care requirements. The primary outcomes were annual patient churn and median length of health plan enrollment duration. Propensity score (PS) matching was conducted between the groups utilizing patient demographics to balance comorbidities between groups. Comorbidity was described with the National Cancer Institute comorbidity index (NCI CI). Appropriate descriptive statistics were calculated and Cox proportional hazards (CPH) models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). Results: Overall, 3.2 million patients met the eligibility criteria, with 18% having cancer. Significant differences in the unmatched population were found, with the cancer group being older and having more comorbidities (p &lt; 0.001). Following PS matching, the differences in underlying demographic variables were minimal, despite being statistically significant. Unadjusted annual churn rate, defined as the percent of cancer patients leaving the health plan per year, averaged 25.44% overall, with the non-cancer group experiencing more churn most years (Table). Median length of health plan enrollment duration was 716 days (Interquartile range (IQR) = 819) overall, with the cancer group having less median duration than the non-cancer group in the matched analysis (713 [IQR 808] vs. 717 [IQR 822], p &lt; 0.001). After adjusting for the variables in the model, having a cancer diagnosis was associated with decreased risk of health plan disenrollment in multivariate CPH regression (HR 0.987 [95% CI 0.983 – 0.991]). Additional factors that increased the risk of disenrollment included: male gender (HR 1.011 [1.008-1.015]), Medicare eligibility (HR 1.290 [1.279-1.301]) and increasing NCI CI (1.124 [1.118-1.129]). Conclusions: Cancer patients experienced less churn from their health plan over a five-year follow-up. They were less at risk for disenrollment at any time than non-cancer patients when confounders are accounted for in multivariate modeling.[Table: see text]

The Prognostic Value of Eight Comorbidity Indices in Older Patients with Cancer: The ELCAPA Cohort Study.

Simple SummaryA prognostic assessment is crucial for making cancer treatment decisions. However, the frequent presence of comorbidities makes this assessment particularly challenging in older adults. Many comorbidity indices are available, but none have been developed for older patients with cancer. We assessed the prognostic performance (relative to one-year mortality) of eight comorbidity indices in a cohort of older patients with cancer. All the comorbidity indices were independently associated with 1-year mortality in the whole study population, and had very good discriminant ability. Among patients with metastatic cancer, only CIRS-G was independently associated with 1-year mortality.Background: A prognostic assessment is crucial for making cancer treatment decisions in older patients. We assessed the prognostic performance (relative to one-year mortality) of eight comorbidity indices in a cohort of older patients with cancer. Methods: We studied patients with cancer aged ≥70 included in the Elderly Cancer Patient (ELCAPA) cohort between 2007 and 2010. We assessed seven nonspecific indices (Charlson Comorbidity Index (CCI), three modified versions of the CCI, the Elixhauser Comorbidity Index, the Gagne index, and the Cumulative Illness Rating Scale for Geriatrics (CIRS-G)) and the National Cancer Institute Comorbidity Index. Results: Overall, 510 patients were included. Among patients with nonmetastatic cancer, all the comorbidity indices were independently associated with 1-year mortality (adjusted hazard ratios (aHRs) of 1.44 to 2.51 for one standard deviation increment; p < 0.05 for all) and had very good discriminant ability (Harrell’s C > 0.8 for the eight indices), but were poorly calibrated. Among patients with metastatic cancer, only the CIRS-G was independently associated with 1-year mortality (aHR (95% confidence interval): 1.26 [1.06–1.50]). Discriminant ability was moderate (0.61 to 0.70) for the subsets of patients with metastatic cancer and colorectal cancer. Conclusion: Comorbidity indices had strong prognostic value and discriminative ability for one-year mortality in older patients with nonmetastatic cancer, although calibration was poor. In older patients with metastatic cancer, only the CIRS-G was predictive of one-year mortality.

The Utility of Comorbidity Indices in Assessing Head and Neck Surgery Outcomes: A Systematic Review.

To evaluate the utility of comorbidity index (CI) scores in predicting outcomes in head and neck surgery (HNS). The CIs evaluated were the Charlson Comorbidity Index (CCI), Elixhauser Comorbidity Index (ECI), Kaplan-Feinstein Index (KFI), American Society of Anesthesiologists Physical Status (ASA-PS), Adult Comorbidity Evaluation-27 (ACE-27), National Cancer Institute Comorbidity Index (NCI-CI), and the Washington University Head and Neck Comorbidity Index (WUHNCI). We report a systematic review according to the 2009 Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Electronic databases (PubMed, Cochrane, and Embase) and manual search of bibliographies identified manuscripts addressing how CI scores related to HNS outcomes. A total of 116 studies associated CI scores with HNS outcomes. CIs were represented in the literature as follows: ASA-PS (70/116), CCI (39/116), ACE-27 (24/116), KFI (7/116), NCI-CI (3/116), ECI (2/116), and WUHNCI (1/116). The most frequently cited justification for calculating each CI (if provided) was: CCI for its validation in other studies, ACE-27 for its utility in cancer patients, and ECI for its comprehensive design. In general, the CCI and ACE-27 were predictive of mortality in HNS. The ECI was most consistent in predicting >1-year mortality. The ACE-27 and KFI were most consistent in predicting medical complications. Despite inconsistencies in the literature, CIs provide insights into the impact of comorbidities on outcomes in HNS. These scores should be employed as an adjunct in the preoperative assessment of HNS patients. Comparative studies are needed to identify indices that are most reliable in predicting HNS outcomes. NA Laryngoscope, 132:1388-1402, 2022.

Healthcare resource use (HRU) by infusion setting of chimeric antigen receptor T-cell (CAR-T) in patients with relapsed and refractory (r/r) diffuse large B-cell lymphoma (DLBCL): A retrospective cohort study using CMS 100% Medicare database.

e19550 Background: Axicabtagene ciloleucel (axi-cel) and tisagenlecleucel (tisa-cel) are CAR-T therapies that were approved for r/r DLBCL in 2017 and 2018, respectively. While majority of the CAR-T infusions occur at inpatient (IP) setting in clinical trials, CAR-T infusions can also occur in the outpatient (OP) setting. This study aimed to compare the real-world HRU between IP vs. OP infusion of CAR-T among patients with r/r DLBCL. Methods: Adult patients with r/r DLBCL receiving tisa-cel or axi-cel were selected from the CMS 100% Medicare data from 2017 to 2019 and classified into IP and OP cohorts based on CAR-T infusion setting. Number of IP, OP, intensive care unit (ICU) visits, IP days, and ICU days by month post-CAR-T infusion were compared between cohorts using generalized linear models, adjusting for age, sex, race, and National Cancer Institute comorbidity index. Average length of stay (LOS) per IP episode during the first month was also described. Results: A total of 430 patients receiving CAR-T (380 IP and 50 OP) were identified. Among those with CAR-T regimen identifiable in the OP cohort, 90.2% received tisa-cel and 9.8% received axi-cel. Mean age at CAR-T infusion in IP and OP cohorts was 70.8 and 68.4 years, respectively. Most of the CAR-T infusions occurred in 2019 (66.6% in IP cohort and 74.0% in OP cohort). During the first month post-CAR-T infusion, OP cohort had significantly lower number of IP visits, IP days, ICU stays, and ICU days compared to the IP cohort. Average LOS per IP episode was 14.2 days in the IP cohort and 7.1 days in the OP cohort. Number of IP visits, IP days, and ICU days were nominally lower while number of OP visits were nominally higher in the OP cohort compared to the IP cohort in subsequent months (Table). Conclusions: Over 90% of the patients treated with CAR-T in the OP setting received tisa-cel. Patients receiving CAR-T in the OP setting had lower resource use of IP and ICU compared to patients receiving CAR-T in the IP setting.[Table: see text]

Abstract PS10-09: Real-world analysis of concomitant medication use with potential drug-drug interactions (DDI) in patients with metastatic breast cancer (MBC) treated with cylin dependent kinase (CDK) 4/6 inhibitors

Abstract Background: In combination with endocrine therapy, the CDK4/6 inhibitors (CDK4/6i) ribociclib, palbociclib, and abemaciclib have improved progression free survival and in some cases overall survival in women with hormone receptor positive (HR+)/HER2 negative MBC. Use of concomitant medications and the potential for drug-drug interactions (DDI) is an important issue in clinical oncology, particularly among patients with MBC treated for long durations of time with CDK4/6i, and could lead to sub-optimal medication adherence or subsequent dose reductions/discontinuations. Objective: To describe concomitant medication use that could lead to DDI with CDK4/6i as well as CDK4/6i dosing, adherence, and discontinuation patterns in real-world clinical practice. Methods: Adult women with HR+/HER2- MBC initiating treatment with ribociclib, palbociclib, or abemaciclib as the first CDK4/6i (index therapy) were retrospectively identified from the Optum Clinformatics Data Mart (1/1/2017 - 9/30/2019), a large US healthcare claims database. Eligibility included 3 months of baseline (pre-index date) and at least 3 months of follow-up (post-index date) data. Concomitant medications (identified from the literature) evaluated at baseline included CYP3A inhibitors and inducers, P-glycoprotein (P-gp) inhibitors and inducers, and medications associated with risk of torsades de pointes (TdP). Treatment persistence was analyzed using Kaplan-Meier (KM) as time from index date to discontinuation, defined as an interruption of at least 90 consecutive days of the index treatment or end of patient enrollment or switch to another medication. Adherence was measured by proportion of days covered (PDC), using the recommended administration schedule of 21 days of treatment followed by 7 days off. Results: A total of 2,994 women were included: 184 initiated ribociclib as first CDK4/6i; 2,550 palbociclib; and 260 abemaciclib. Median duration of follow-up was 13.7 [Interquartile range (IQR)] 11.8); 13.1 (IQR 13.5); and 9.3 (IQR 9.2) months. The majority in each cohort were postmenopausal (ribociclib: 89.1%; palbociclib: 92.8%; abemaciclib: 90%) and received the index CDK4/6i as &amp;gt; 2nd line of therapy (ribociclib: 81.5%; palbociclib: 87.6%; abemaciclib: 88.9%). Mean age (66.4; 66.8; and 65.3 yrs) and National Cancer Institute comorbidity index [mean/SD: 1.2 (1.6); 1.2 (1.7); 1.1 (1.6)] were similar for the ribociclib, palbociclib, and abemaciclib cohorts, respectively. Patients with ≥ one concomitant medication (60.3%; 64.2%; 65.8%) and those with &amp;gt; one medication associated with TdP (57.1%; 59.4%; 61.9%) were similar for the 3 cohorts. The CDK4/6i discontinuation rates, starting dose, dose reduction, and adherence results are listed below (Table). Conclusions: Use of concomitant medications that could lead to a DDI with a CDK4/6i, especially those with risk of TdP, CDK4/6i treatment discontinuation, and adherence was similar between ribociclib, palbociclib, and abemaciclib in this real-world retrospective descriptive study. More patients in the ribociclib cohort maintained starting dose and less decreased to &amp;lt;50% of the starting dose compared to palbociclib and abemaciclib, although the cohort is small. Results are limited by the relatively smaller number in the ribociclib and abemaciclib cohorts. Descriptive analysis on characteristics in follow up period by index drug groupRibociclib (N = 184)Palbociclib (N = 2550)Abemaciclib (N = 260)Discontinuation of Index Treatment, n (%)96 (52.2)1266 (49.7)123 (47.3)Starting dose, mean (SD)532.6 (141.1)118.5 (13.4)287.7 (56.6)Patients with first time dose changeNo change during the entire follow up period, n (%)148 (80.4)1740 (68.2)176 (67.7)Decrease &amp;gt; 50%, n (%)7 (3.8)0 (0)5 (1.9)Decrease ≤ 50%, n (%)20 (10.9)773 (30.3)68 (26.2)Adherence (PDC), mean (SD)0.85 (0.2)0.87 (0.2)0.87 (0.2) Citation Format: Hope S. Rugo, Sanjeev Balu, Yunfeng Li, Guifang Chen, Xin Li, Stuart Turner, Roxana Sin. Real-world analysis of concomitant medication use with potential drug-drug interactions (DDI) in patients with metastatic breast cancer (MBC) treated with cylin dependent kinase (CDK) 4/6 inhibitors [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS10-09.