▪BACKGROUNDMost CLL patients in the US are treated with chemoimmunotherapy (CIT) or ibrutinib; rarely do patients receive chemotherapy (CT) alone. VEN is approved for relapse/refractory (R/R) CLL patients who received one prior therapy. While treatment selection is based on risk stratification, comorbidities, patient choice, and physician preference, the economic impact of selecting VEN versus CT/CIT in R/R CLL is unknown and in the absence of prospective comparative studies, could play a role in decision-making. We aimed to compare real-world HRU of VEN versus CT/CIT-treated CLL patients receiving therapy in the second line setting.PATIENTS and METHODSCLL patients initiating second line therapy (2L) between 01/01/2016-03/31/2018 were selected from the Symphony Health's Integrated Dataverse (IDV) dataset. HRU for patients receiving VEN or CT/CIT regimens were compared from the start of the first cycle of 2L and for 3 months after treatment and reported as per-patient per-month (PPPM). Patients were ≥18 years at diagnosis and were required to have treatment after CLL diagnosis. HRU was reported for the inpatient (inpt), emergency room (ER), physician office visit (OV) or other outpatient ambulatory visits (Outpt) settings. Time to initiation was assessed from CLL diagnosis to the start of the second line of therapy. P-values were generated using chi-square tests for categorical variables and Wilcoxon test for means, as utilization and cost outcomes are often non-normally distributed.RESULTSAmong the 385 CLL patients considered in this study, 154 were treated with VEN [median age 64 years (range: 21-79)], 121 were treated with CT (median age 70 years, min 19 and max 79) and 110 were treated with CIT [median age 65 years, (range: 33-78)]. CIT in this setting were only FCR (25 patients) or BR (85 patients). There were no significant differences in gender distribution between cohorts, but higher percentage of VEN-treated patients were on Medicare/Medicaid compared to CIT patients [61% vs 52% (CIT)]. Median follow-up from initiation of 2L was significantly shorter for VEN patients when compared to CT or CIT patients (7.7 months vs 16.2 and 18.6, p-value <0.0001); likely due to later uptake in prescribing VEN relative to study period initiation. Median time from CLL diagnosis to the initiation of 2L therapy was significantly longer for VEN patients when compared to CT/CIT patients (17.3 vs 11.3 and 10.5, p-value < 0.0001).VEN inpt costs were significantly lower than CT costs ($1,615.48 vs $2,592.52, p-value <0.05) however there were no statistically significant differences observed for inpt costs between the VEN and CIT. The costs of ER visits were significantly lower for CT and CIT patients when compared to VEN ($321.48 vs $147.52 and $181.03, p<0.0001). The cost of office visits was also significantly lower for CT/CIT patients when compared to VEN ($1,971.39 vs $807.96 and $776.10, p<0.0001). Outpt visit costs were higher for CT/CIT patients when compared to VEN ($1,437.12 vs $5,163.91 and $4,824.44, p<0.0001). The total cost of medical care was significantly higher in both the CT and CIT groups when compared to VEN ($6,075.81 and $5,514.52 vs $2,439.52, p-value <0.0001); (Table).CONCLUSIONS: In R/R CLL patients, total costs of care were significantly lower in VEN patients compared to CT or CIT patients potentially implying cost-effectiveness (considering equal efficacy/toxicity). This analysis may inform shared decision-making when deciding on second line therapy especially in a value-based care environment. DisclosuresNabhan:Cardinal Health: Employment, Equity Ownership. Mato:Medscape: Honoraria; Regeneron: Research Funding; Portola: Research Funding; AstraZeneca: Consultancy; Acerta: Research Funding; Celgene: Consultancy; Prime Oncology: Honoraria; Johnson & Johnson: Consultancy; TG Therapeutics: Consultancy, Research Funding; AbbVie: Consultancy, Research Funding; Pharmacyclics, an AbbVie Company: Consultancy, Research Funding. Kish:Cardinal Health: Employment. Nero:Cardinal Health: Employment.