e19135 Background: Real-world data sources have historically provided limited information about the occurrence of disease progression. As a result, progression-free survival (PFS), a standard effectiveness outcome measure in oncology, has been estimated using proxies such as time-to-discontinuation (TTD) or time-to-next-treatment (TTNT). Curation of unstructured electronic medical record (EMR) data make it possible to calculate PFS from directly observed progression. The aim of this research was to compare TTD and TTNT as proxy indicators with PFS determined from direct statements regarding progression in the medical record and to compare effect sizes on treatment-based groups across these endpoints. This report cites findings from the metastatic breast cancer (mBC) setting. Methods: Previously curated EMR data were collected from Concerto’s Definitive Oncology Dataset for adult, female, hormone receptor-positive/human epidermal growth factor receptor-negative mBC patients diagnosed 2008 or later who received at least one line of systemic therapy. Patients were grouped based on any receipt vs. no receipt of an aromatase inhibitor (AI) in first line (1L). Kaplan-Meier and Cox regression methods were used to calculate PFS, TTD, and TTNT in 1L and OS from start of 1L. Results: The study included 378 patients, of which 138 (36.5%) were de novo stage IV or metastatic. The mean patient age was 60.3 years (SD 13.3), 57.1% were Caucasian, and 68.3% were postmenopausal. Conclusions: Estimates of TTD and TTNT aligned closely, suggesting that nearly all patients who discontinued initial therapy received subsequent treatment. Notably, TTNT and TTD were both meaningfully shorter than PFS, suggesting that their use as proxy indicators may systematically underestimate PFS. Further, analysis based on receipt of AI indicates that comparative effects on TTD or TTNT may produce quite different results than those for PFS and OS. [Table: see text]

Aim: We report real-world treatment patterns and outcomes in patients with PD-L1+ non-small cell lung cancer (NSCLC). Methods: This retrospective, observational study using the ConcertAI Oncology Dataset (Symphony AI, CA, USA), included patients with PD-L1+ (≥1% expression) metastatic NSCLC who began first-line (1L) treatment between 2016 and 2019. Treatment outcomes were assessed by treatment class (immune checkpoint inhibitor [ICI] monotherapy, ICI combinations or chemotherapy). Results: In total, 128 (25.5%), 237 (47.3%) and 136 patients (27.1%) received 1L chemotherapy, 1L ICI monotherapy and 1L ICI combinations, respectively. ICI combinations and monotherapy had improved clinical outcomes versus chemotherapy. Adjusted analyses showed no significant difference in outcome between ICI monotherapy and ICI combinations. Conclusion: ICI-based treatments are being increasingly adopted into clinical practice and were associated with better outcomes versus chemotherapy.

No abstract

57 Background: Biosimilars have potential to reduce healthcare costs and increase access in the United States, but lack of uptake has contributed to lost savings. Filgrastim-sndz was the first FDA-approved biosimilar, and much can be learned by evaluating its uptake. In February 2016, the US Oncology Network converted to filgrastim-sndz as its short-acting granulocyte colony-stimulating factor (GCSF) of choice for prevention of febrile neutropenia (FN) following myelosuppressive chemotherapy (MCT). To understand utilization and cost patterns, this study analyzes real-world data of GCSFs within a community oncology network during the initial period of conversion to the first biosimilar available in the US. Methods: This descriptive retrospective observational study used electronic health record data for female breast cancer (BC) patients receiving GCSF and MCT at high risk of FN. Patient cohorts were defined by first receipt of either filgrastim or filgrastim-sndz during the 410 days before and after biosimilar conversion. Healthcare resource utilization (HCRU) and costs for GCSF and complete blood counts (CBC) were collected at GCSF initiation through the earliest of 30 days following end of MCT, loss to follow up, death, or data cutoff. Results: 146 patients were identified: 81 (55.5%) filgrastim and 65 (44.5%) filgrastim-sndz. No directional differences existed in baseline characteristics between the cohorts. Higher proportions of filgrastim-sndz patients received dose-dense MCT (33.8% vs 22.2%). Time trends show an initial spike in HCRU and cost for filgrastim-sndz patients after formulary conversion, which subsequently decreased and converged to that of the filgrastim cohort after 12 months. When aggregated, the overall median total administration counts, per patient per month (PPPM) and dosage, were marginally higher for filgrastim-sndz (5 vs 3; 2.9 vs 1.4; 1920 vs 1440 mcg, respectively). Median PPPM costs were higher for filgrastim-sndz ($803 vs $545). Median CBC utilization and costs were higher for filgrastim-sndz (2.8 vs 2.5; $28 vs $23, respectively). Conclusions: This study provides insight into real-world HCRU and cost patterns after formulary conversion to a biosimilar for BC patients receiving MCT and GCSF. As a descriptive study, causal inferences cannot be made and an underlying effect from index chemotherapy cannot be excluded. Convergence of HCRU and costs after 12 months suggests that overall results may be driven by behavior at initial formulary switch. Since filgrastim-sndz was the first US biosimilar approved, the uptake may be indicative of an experience with biosimilar acceptance in general. Future real-world studies of biosimilars must consider inconsistent utilization and practice trends during the time frame directly following formulary conversion.

No abstract