Health Care Utilization Associated with Adverse Events (aes) among Metastatic Non-Small Cell Lung Cancer (mnsclc) Patients Treated with Immunotherapy or Chemotherapy.

e20655 Background: Chemotherapy and immunotherapy (IO) are associated with increased overall survival in patients with mNSCLC, yet real-world data on AE-associated healthcare utilization are sparse. This study assessed incidence and utilization associated with AEs among patients initiating first-line treatment for mNSCLC with IO, IO with chemotherapy (IC), or chemotherapy alone (CH). Methods: Data were claims from commercial and Medicare Advantage patients (Jan 2008-Feb 2018). Inclusion criteria were mNSCLC, health plan enrollment for ≥6 months pre- (baseline) and ≥1 month post-index date; initiation of recommended systemic therapy for mNSCLC. Excluded were targeted or small-cell lung cancer therapy, and baseline surgery or other systemic therapy. AE incidence and healthcare utilization were measured from start of 1st line therapy until earliest of start of 2nd line therapy or 180 days. AEs evaluated included hematologic, GI, endocrine, infections, infusion reactions, muscle, neurological, and respiratory. Results: Cohorts were 8,818 CH, 482 IO, and 412 IC. Mean age was older for IO (72 yrs, vs. 69 IC, 68 CH; P < 0.001). IOs used were atezolizumab (n = 12), nivolumab (n = 148), and pembrolizumab (n = 673). Common chemotherapies were carboplatin (74%), pemetrexed (30%), and paclitaxel or etoposide (22%). Overall, 74% had ≥1 AE; incidence rate ratios (IRR) vs. IO (95% CI) were IC 1.36 (1.15-1.60) and CH 1.43 (1.28-1.61). Frequent AEs were blood conditions (43%), GI (32%), and infections (29%). IRR vs. IO included infections (1.94 CH), GI (1.71 IC, 1.90 CH), anemia (4.05 IC, 5.68 CH), leukopenia (5.69 IC, 22.28 CH), and thrombocytopenia (3.70 CH). CH had lower rates vs. IO for hyperthyroidism (2% IO; IRR 0.16 CH) and hypothyroidism (12% IO; IRR 0.19 CH). AE overlaps with infection were common; 61% of patients with infection had a hospitalization that involved both infection and another AE. AE-associated visits varied by cohort; ambulatory: 46% (IO), 50% IC, 61% CH; ER: 25% IO, 27% IC, 30% CH; inpatient: 29% IO, 35% IC, 37% CH (P < 0.05 for all CH vs IO). Conclusions: AE-associated visits in mNSCLC were lower for IO-treated than for CH or IC-treated patients.