Real-world treatment patterns among patients with diffuse large B-cell lymphoma (DLBCL) treated with CD19-directed chimeric antigen receptor T-cell therapy (CAR T)

e19351 Background: CAR T, approved in the US as of October 2017, impacted the treatment landscape for patients with relapsed or refractory (R/R) DLBCL after ≥2 lines of therapy, but there is little known about real-world (RW) treatment patterns in patients who fail or do not respond to CAR T. No treatments of proven benefits are available after CAR T treatment failure. The objective of this study was to describe RW treatment patterns after CAR T. Methods: From MarketScan Commercial/Medicare claims databases (2017‒2018) we identified adult DLBCL patients who received approved CD19-directed CAR T (treatment date = index date). Eligible patients had ≥6 months continuous health plan enrollment prior to index date (i.e. baseline period) and were followed until plan disenrollment or December 31, 2018. Patients with a diagnosis of acute lymphoblastic leukemia over the baseline period were excluded. We identified the first and second treatments after CAR T with systemic chemotherapy, targeted therapy, immunotherapy, hematopoietic stem cell transplant (SCT), radiation therapy (RT), or a second round of CAR T therapy. Kaplan–Meier estimators were used to estimate risk of subsequent treatment and time to next treatment. Results: We identified 56 patients with DLBCL treated with CAR T (mean age [SD]: 57.3 years [9.9]; 23.2% female; 80.4% commercially insured). All patients received CAR T in the inpatient setting, median (Q1‒Q3) length of stay was 15 days (12‒19). Out of 56 patients, 19 initiated a treatment following CAR T; risk of subsequent treatment at 6 months post index was 45.6% (95% CI: 25.4‒60.4%) and median days from CAR T to next treatment was 233 days (95% CI: 139‒NA). Out of 19 patients, 3 initiated a second treatment following CAR T, within 8‒69 days of the first treatment. Over a median (Q1‒Q3) follow-up of 139.5 days (90.5‒194) following CAR T, of the 19 patients treated after CAR T, 57.9% were treated with immunotherapy, 36.8% with RT, 26.3% with targeted therapy, 21.1% with SCT, 15.8% with chemotherapy, and 0% with a second round of CAR T. Conclusions: There are few multicenter studies reporting RW treatment patterns in patients who received CAR T. In this study, risk of subsequent treatment at 6 months following CAR T in a RW setting was almost 50%. Although limited by duration of follow-up, our results suggest that additional, effective salvage treatment strategies are needed for patients who do not respond to CAR T or do not achieve a durable response to CAR T. Updated results using 2019 data will be presented.