REAL-WORLD TREATMENT PATTERNS AND CLINICAL OUTCOMES IN PREVIOUSLY UNTREATED LOCALLY ADVANCED OR METASTATIC TRIPLE-NEGATIVE BREAST CANCER, BY PD-L1 STATUS: A NORSTELLALINQ US LINKED CLAIMS-EHR STUDY

Author(s)

Becky Hollenberg, MPH1, Allison Perry, PhD1, Rahul Das, PhD1, Karan Bhanot, PhD1, ilan behm, MPH2.
1Norstella, New York, NY, USA, 2Norstella, Englewood, CO, USA.
OBJECTIVES: To characterize first-line treatment patterns and real-world clinical outcomes among adults with previously untreated locally advanced inoperable or metastatic triple-negative breast cancer (la/m TNBC) in the United States, stratified by PD-L1 status.
METHODS: Retrospective study using NorstellaLinQ’s US real-world linked electronic health record (EHR), open-claims, and closed-claims data (January 2018-December 2024). From 4,437,456 patients with breast cancer, adults with la/m TNBC initiating systemic therapy (index 2020-2023) were identified. PD-L1 status was derived from structured laboratory data and NLP-assisted abstraction of clinical notes. Treatment patterns by line of therapy (LOT), real-world time on treatment (rwTOT), time to next treatment (rwTTNT), and overall survival (rwOS) were assessed using Kaplan-Meier methods.
RESULTS: The final cohort comprised 724 patients (PD-L1 positive 398; negative 163; remainder unknown/undocumented); 99.6% were female, mean age 59 years, and 70% had ECOG 0-1. Common metastatic sites were lymph nodes (34%), bone (21%), lung (20%), and liver (16%). First-line treatment differed substantially by PD-L1 status: 61% of PD-L1-positive patients received chemotherapy plus immunotherapy, versus 74% of PD-L1-negative patients receiving chemotherapy alone. Overall, 59% initiated second-line and 34% third-line therapy. Antibody-drug conjugates were used predominantly after first line, accounting for 19% of second-line and 27% of third-line regimens. Median rwTOT remained under 3 months across all lines (2.6, 2.8, 2.9 months), and median rwTTNT was 6.5 and 7.2 months. Median rwOS was not reached during available follow-up (108 deaths).
CONCLUSIONS: In real-world la/m TNBC, first-line treatment varied by PD-L1 status, but time on treatment was short and many patients proceeded to subsequent lines, with antibody-drug conjugates increasingly used later. Despite biomarker-guided first-line selection, treatment duration remained consistently short across all lines, highlighting substantial unmet need. Linked claims and EHR data, supplemented with PD-L1 ascertainment from clinical notes, enabled characterization of biomarker-defined treatment patterns difficult to evaluate using structured data alone.

Conference/Value in Health Info

2026-11, ISPOR Europe 2026, Vienna, Austria

Value in Health, Volume 29, Issue 12S

Code

CO201

Topic

Clinical Outcomes

Topic Subcategory

Comparative Effectiveness or Efficacy, Relating Intermediate to Long-term Outcomes

Disease

Oncology, Personalized & Precision Medicine

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