Goldberg, Sarah B.

8013 Background: For patients (pts) with unresectable locally-advanced NSCLC, standard of care involves durva consolidation after concurrent CRT, although its benefit in ALK+ tumors is unclear. The ALINA trial demonstrated adjuvant efficacy of alectinib in resected ALK+ NSCLC, but the optimal consolidation strategy for unresectable locally-advanced ALK+ NSCLC remains elusive. Methods: This multi-institutional international retrospective analysis included pts with stage III unresectable ALK+ NSCLC who received an ALK TKI, durva, or obs alone after concurrent CRT between 2015-2022. Baseline characteristics of age, sex, smoking history, and PD-L1 status were collected. Clinical outcomes including real-world progression-free survival (rw-PFS), overall survival (OS), and treatment-related adverse events (trAE) as defined using CTCAE 5.0 were assessed, and multivariate cox regression models were performed. Results: Sixty-four pts across 16 institutions were included. The median age was 57 (IQR 49-66) and 61% were females. The majority had adenocarcinoma (97%) and had never smoked (58%). 15 received ALK TKI (10 alectinib, 3 crizotinib, 1 brigatinib, 1 lorlatinib), 30 received durva, and 19 received obs alone. There was no significant difference in stage of cancer (IIIA, B, or C) or PD-L1 status among groups. After adjusting for stage and age at CRT initiation, median rw-PFS was significantly longer for ALK TKI (rw-PFS not reached [NR], 95% CI 22.7-NR) vs durva (11.3 months (mo), 95% CI 9.2-18.5, p= 0.005, HR = 0.12) or obs (7.4 mo, 95% CI 3.4-12.5, p < 0.0001). Two (13%) pts progressed on ALK TKI. 25 pts (83%) progressed on durva leading to treatment with ALK TKI in 23, and 18 (95%) progressed while under obs leading to treatment with ALK TKI in 15. 3-year OS was 100% for ALK TKI vs 90.5% for durva vs 63.5% for obs. Median OS was NR (95% CI NR-NR) for both ALK TKI and durva vs 70.6 mo (24.9-NR) in the obs group ( p= 0.03 for both ALK TKI and durva compared to obs). Median duration of therapy was 24.7 mo with ALK TKI and 6.5 mo with durva. Grade ≥3 trAE occurred in 27%, 7%, 6% of pts treated with ALK TKI (1 fatigue, 1 diarrhea, 1 hyperbilirubinemia, 1 pneumonitis), durva (1 fatigue, 1 neutropenia), and obs (1 neutropenia) respectively. Treatment discontinuation due to toxicity occurred in 4 (27%) with ALK TKI and in 3 (10%) with durva. Conclusions: In this retrospective study of stage III ALK+ NSCLC, consolidation ALK TKI demonstrated clinically meaningful improvement in PFS and OS over durva and obs, while showing a slightly higher rate of trAE over dura and obs. Furthermore, we show a high rate of progression following CRT alone in ALK+ NSCLC. These findings underscore the need for prospective molecularly driven trials to determine the optimal consolidation therapy for unresectable ALK+ NSCLC.

8567 Background: Adjuvant osimertinib (osi) improves disease-free survival (DFS) in patients (pts) with resected, early-stage, EGFR-mutant (EGFRmut) NSCLC, yet the benefit of osi after CRT in pts with unresectable locally advanced NSCLC is unknown. Post-hoc analysis of the PACIFIC trial showed a lack of survival benefit with consolidation durva versus placebo in pts with EGFRmut NSCLC. Comparisons between consolidation durva and EGFR TKIs in unresectable EGFRmut NSCLC following CRT are lacking. Methods: We conducted a multi-institutional retrospective analysis of pts with stage III unresectable EGFRmut NSCLC (exon19 deletion, exon21 L858R), who received EGFR TKI or durva after ≥ 2 cycles of platinum-based chemotherapy plus definitive radiation therapy between 2015-2022. Baseline characteristics including age, sex, smoking history, PD-L1 status, and outcomes on DFS, overall survival (OS), and safety were collected. Multivariable (MVA) cox regression analysis was used for statistical analysis. Treatment-related adverse events (trAE) were defined using CTCAE 5.0. Results: Seventeen pts from 12 institutions received an EGFR TKI (osi, n=15; erlotinib, n=2), and 13 pts received consolidation durva. Median follow-up was 23 months. Median age of all pts was 61 years (IQR:52-72) and 76.7% were female. Most pts in both groups had never-smoked and had adenocarcinoma. All pts received ≥ 60 Gy of radiation with concurrent chemotherapy. PD-L1 expression was ≥ 50% in 1/10 (10%) pts treated with durva vs 6/13 (46.2%) treated with TKI, p=0.09. Median duration on treatment for EGFR TKI and durva was 12.2 months and 4.8 months, respectively. Pts treated with EGFR TKI had significantly longer 24-month DFS versus pts treated with durva after adjusting for stage (3A vs 3B vs 3C) (Table). Any grade tRAE occurred in 58.8% (10/17) of pts treated with EGFR TKI vs 38.5% (5/13) with durva. Grade > 3 tRAE occurred in 15.4% (1 pneumonitis and 1 AST/ALT elevation) of pts treated with durva but in none of pts treated with EGFR TKI. Three pts within each arm came off treatment due to toxicity (EGFR TKI: 1 pneumonitis and 2 dermatitis; durva: 1 of each pneumonitis, Type 1 diabetes, AST/ALT elevation). Conclusions: EGFR TKI therapy after definitive CRT was associated with significantly longer DFS compared to durva in this retrospective study of pts with stage III unresectable EGFRmut NSCLC, without unanticipated safety signals. Follow-up is ongoing and OS outcomes will be evaluated subsequently. Further investigation is warranted to define the optimal therapy for locally advanced EGFRmut NSCLC. [Table: see text]

Abstract Neurofilament light chain, a putative measure of neuronal damage, is measurable in blood and CSF and is predictive of cognitive function in individuals with Alzheimer’s disease. There has been limited prior work linking neurofilament light and functional connectivity, and no prior work has investigated neurofilament light associations with functional connectivity in autosomal dominant Alzheimer’s disease. Here, we assessed relationships between blood neurofilament light, cognition, and functional connectivity in a cross-sectional sample of 106 autosomal dominant Alzheimer’s disease mutation carriers and 76 non-carriers. We employed an innovative network-level enrichment analysis approach to assess connectome-wide associations with neurofilament light. Neurofilament light was positively correlated with deterioration of functional connectivity within the default mode network and negatively correlated with connectivity between default mode network and executive control networks, including the cingulo-opercular, salience, and dorsal attention networks. Further, reduced connectivity within the default mode network and between the default mode network and executive control networks was associated with reduced cognitive function. Hierarchical regression analysis revealed that neurofilament levels and functional connectivity within the default mode network and between the default mode network and the dorsal attention network explained significant variance in cognitive composite scores when controlling for age, sex, and education. A mediation analysis demonstrated that functional connectivity within the default mode network and between the default mode network and dorsal attention network partially mediated the relationship between blood neurofilament light levels and cognitive function. Our novel results indicate that blood estimates of neurofilament levels correspond to direct measurements of brain dysfunction, shedding new light on the underlying biological processes of Alzheimer’s disease. Further, we demonstrate how variation within key brain systems can partially mediate the negative effects of heightened total serum neurofilament levels, suggesting potential regions for targeted interventions. Finally, our results lend further evidence that low-cost and minimally invasive blood measurements of neurofilament may be a useful marker of brain functional connectivity and cognitive decline in Alzheimer’s disease.