Purpose: Despite recent advances, approximately 50% of patient with metastatic melanoma eventually succumb to the disease. Patients with melanomas harboring a BRAF mutation (BRAF^Mut) have a worse prognosis than those with wildtype (BRAF^WT) tumors. Unexpectedly, interim AVAST-M Phase III trial data reported benefit from adjuvant anti-VEGF bevacizumab only in the BRAF^Mut group. We sought to find mechanisms underpinning this sensitivity. Methods: We investigated this finding in vitro and in vivo using melanoma cell lines and clones generated by BRAF^V600E knock-in on a BRAF^WT background. Results: Compared with BRAF^WT cells, isogenic BRAF^V600E clones secreted more VEGF and exhibited accelerated growth rates as spheroids and xenografts, which were more vascular and proliferative. Recapitulating AVAST-M findings, bevacizumab affected only BRAF^V600E xenografts, inducing significant tumor growth delay, reduced vascularity and increased necrosis. We identified 814 differentially expressed genes in isogenic BRAF^V600E/BRAF^WT clones. Of 61 genes concordantly deregulated in clinical melanomas ROR2 was one of the most upregulated by BRAF^V600E. ROR2 was shown to be RAF-MEK regulated in BRAF^V600E cells and its depletion suppressed VEGF secretion down to BRAF^WT levels. The ROR2 ligand WNT5A was also overexpressed in BRAF^Mut melanomas, and in ROR2-overexpressing BRAF^V600E cells MEK inhibition downregulated WNT5A and VEGF secretion. Conclusions: These data implicate WNT5A-ROR2 in VEGF secretion, vascularity, adverse outcomes and bevacizumab sensitivity of BRAF^Mut melanomas, suggesting that this axis has potential therapeutic relevance.

Purpose: Evaluation of predictors and outcomes in NSCLC patients treated with an immune checkpoint inhibitor (ICI) following a severe immune-related adverse event (irAE). Methods: We included all NSCLC patients receiving ≥1 ICI cycle and corticosteroids for CTCAE Grade ≥3 irAEs between 2017 and 2023 from three UK NHS teaching hospitals. Progression-free survival (PFS) and overall survival (OS) after the 1st irAE, best overall response (BOR) to ICI, and predictors of clinical benefit were evaluated. Kaplan–Meier, Cox and logistic regression models, and Wilcoxon tests were used. Results: We screened 1658 NSCLC patients and identified 80 eligible subjects. The majority of patients had metastatic (n = 50, 63%) vs. localized (n = 30, 37%) NSCLC. Most patients developed a single ≥Grade 3 irAE on 1st line ICI (n = 71, 89%). Overall, 14 (18%) patients developed 2nd irAEs, 7 after rechallenge with ICIs. In the complete cohort, median OS after 1st irAE was 15.84 months (95% CI, 12.45–26.91). Lower neutrophil-to-lymphocyte ratio (NLR), patients receiving >4 cycles of ICI or median duration of ICI of >2.76 months before 1st irAE were associated with improved OS (p < 0.05), the latter two with PFS (p < 0.05). Age, gender, stage, KRAS mutation, PD-L1 and ICI type were not associated with PFS or OS. Pneumonitis as 1st irAE had the worst PFS and OS (p < 0.05). Median starting corticosteroid dose of ≤60 mg for 1st irAE had an improved OS (p = 0.04). Post 1st irAE response associated with better PFS and OS (p < 0.05). Number and duration of irAEs and additional immunosuppressive agents (14% of patients) were not associated with PFS or OS. Conclusions: In ≥Grade 3 irAEs patients managed with corticosteroids, lower baseline NLR, longer ICI use, response to ICI after 1st irAE, and a ≤60 mg corticosteroid dose had promising outcomes.

Purpose: We conducted the largest multinational review to date evaluating outcomes following radiotherapy for non-small cell lung carcinoma (NSCLC) patients with oligoprogressive disease (OPD) on immune checkpoint inhibitors (ICIs). Methods: Patients with NSCLC irradiated to ≤5 progressive lesions while receiving ICIs between 2010 and 2023 were identified. We evaluated predictors of local control (LC), progression-free survival (PFS), and overall survival (OS). Patient demographics, disease characteristics, and survival were analyzed using the Wilcoxon test, Kaplan-Meier methods, and uni-/multivariate Cox models. Results: Out of 1178 treated patients, 103 eligible ones were included. The median OPD lesion was 1; the most common site was the lung (n = 33). The median LC of irradiated OPD lesions was not reached. Median PFS and OS were 6.90 (5.75–12.91) and 23.46 (17.54–37.16) months, respectively. Patient demographics, tumor pathological factors, number of OPD lesions, cumulative tumor volume, radiation modality, and OPD response to prior ICIs before radiation were not associated with these three outcomes. However, LC was associated with intermediate/high radiation doses (p = 0.005) and local response to radiation (p = 0.007). Improved PFS was associated with visceral OPD sites following radiation (p = 0.01). A favorable OS was associated with intermediate/high radiation doses (p = 0.01), local response to radiation (p = 0.006), and duration of last ICI before OPD (p = 0.03). Conclusions: Promising outcomes were observed with ICI and radiation for visceral OPD at intermediate/high doses. Prolonged ICI use before OPD and local response to radiotherapy improved survival. These data can contribute towards guidance of multidisciplinary clinical decision-making for managing OPD in NSCLC patients receiving ICIs.

1 1.1 Background: Immune checkpoint blockers (ICBs) activate CD8 ⁺ T cells to elicit anti-cancer activity but frequently lead to immune-related adverse events (irAEs). The relationship of irAE with baseline parameters and clinical outcome is unclear. We investigated associations between irAE development, CD8 ⁺ T cell receptor diversity and expression and clinical outcome in a non-trial setting. 1.2 Methods: Patients ≥18 years old with metastatic melanoma (MM) receiving combination ICB (ipilimumab plus nivolumab – cICB, n=60) or single-agent ICB (nivolumab/pembrolizumab – sICB, n=78) were prospectively recruited. We retrospectively evaluated the impact of irAEs on survival. This analysis was repeated in an independent cohort of MM patients treated at a separate institution (n=210, cICB:74, sICB:136). We performed RNA sequencing of CD8 ⁺ T cells isolated from patients prior to treatment, analysing T cell receptor clonality differential transcript expression according to irAE development. 1.3 Results: 48.6% of patients experienced treatment-related irAEs within the first 5 cycles of treatment. Development of irAE prior to the 5 ^th cycle of ICB was associated with longer progression-free and overall survival (PFS, OS) in the primary cohort (log-rank test, PFS: P =0.00034; OS: P <0.0001), replicated in the secondary cohort (OS: P =0.00064). Across cohorts median survival for those patients not experiencing irAE was 14.4 (95% CI:9.6-19.5) months vs not-reached (95% CI:28.9 - Inf), P =3.0×10 ⁻⁷ . Pre-treatment performance status and neutrophil count, but not BMI, were additional predictors of clinical outcome. Analysis of CD8 ⁺ T cells from 128 patients demonstrated irAE development was associated with increased T cell receptor diversity post-treatment ( P =4.3×10 ⁻⁵ ). Development of irAE in sICB recipients was additionally associated with baseline differential expression of 224 transcripts (FDR<0.1), enriched in pro-inflammatory pathway genes including CYP4F3 and PTGS2 . 1.4 Conclusions: Early irAE development post-ICB is strongly associated with favourable survival in MM and increased diversity of peripheral CD8 ⁺ T cell receptors after treatment. irAE post-sICB is associated with pre-treatment upregulation of inflammatory pathways, indicating irAE development may reflect baseline immune activation states. Key message: Immune-related adverse events (irAEs) commonly occur in patients with metastatic melanoma treated with immune checkpoint blockade (ICB) therapy. In real world setting we find development of early irAEs post-ICB treatment is associated with survival benefit, indicative of a shared mechanism with anti-tumour efficacy. CD8 ⁺ T cells from patients who develop irAE show increased receptor diversity, and pre-treatment samples from patients who develop irAE post single-agent anti-PD1 show over-expression of inflammatory pathways, indicating baseline immune state can determine irAE development.