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e21161 Background: Patients with stage IV NSCLC undergo frequent restaging scans (RS). While vital to assess treatment response, RS add anxiety and financial burdens to patients. The ideal frequency of RS is unclear. The numerous treatment options available, such as targeted therapy (TT) and immunotherapy (IO), and the variability in frequency of RS in the trials that led to their approval reflect this uncertainty. Due to the lack of clear guidelines about their ideal interval in daily practice, we reviewed the heterogeneity in frequency of RS in those trials, comparing it to the reported progression-free survival (PFS). Methods: In this study, we reviewed the FDA-approved drugs for stage IV NSCLC since 10/18/2016 and selected the TT and IO. Each trial that led to approval was reviewed, collecting the frequency of RS and the median PFS for the intervention (IA) and control arms (CA). Results: 18 TT drugs and 12 IO regimens, with and without chemotherapy (chemo), were found. Among them, the frequency of RS varied from every 4 to 9 weeks (w) upfront, later modified to every 6 to 12 w until disease progression. The median PFS for both groups in the IA ranged from 2.8 to 19.4 months (m), and from 3.0 to 12.4 m in the CA. The TT group had drugs directed at 7 different mutations, and it presented more discrepancy in terms of restaging frequency. The period between RS varied from every 4 to 8 w initially, later modified to every 6 to 12 w. However, 11 of 18 trials had an interval of every 6 w. The shortest median PFS in the IA arm was 5.4 m, and 5.6 m in the CA. While the longest median PFS was 19.4 m in the IA and 12.4 m in the CA. The IO group included 5 regimens with chemo and 7 without. The interval between RS varied from 6 to 9 w originally, to every 8 to 12 w later. Yet, 8 of 12 regimens’ trials scanned patients every 6 w initially. The median PFS in the IA ranged from 2.8 to 10.3 m, and between 3.0 to 6.5 m in the CA. Conclusions: We observed notable heterogeneity among trials regarding the frequency of RS in patients treated for stage IV NSCLC. When comparing these intervals to the median PFS, we noted the shortest PFS reported is longer than most adopted intervals. This may indicate RS were obtained more frequently than needed. The increased frequency of RS raises a burden for patients and the medical system, while contributing to disparities. This finding, coupled with further comparisons between the frequency of RS in trials and in daily practice, may pave the way for prospective studies analyzing the ideal interval for RS. This can lead to a more efficacious and less burdensome strategy for patients. [Table: see text]

e21157 Background: Atezolizumab is superior to docetaxel for patients with advanced non-small-cell lung cancer (NSCLC) who are pretreated with platinum-based chemotherapy based on the POPLAR and OAK trials. However, patients who received prior immunotherapy (IO) were excluded from these trials. The preferred subsequent therapy for these patients remains to be docetaxel +/- ramucirumab. The efficacy and safety of atezolizumab as a subsequent therapy in IO-pretreated patients are unknown. Methods: We conducted a retrospective study of all patients with locally advanced/metastatic NSCLC who were pretreated with IO at Mayo Clinic Florida/Rochester in 2016 - 2022. Patients who received subsequent therapy of atezolizumab alone (Atezo), docetaxel (Doce), or docetaxel + ramucirumab (Doce+Ram) were included. Kaplan-Meier method and log-rank test were used for survival analysis. Results: Among 169 patients included, 51.5% were female, 91.7% were Caucasian. The median age was 67 (35 – 92). The histology was predominantly adenocarcinoma (76.3%). The most common metastatic sites were bone (51.5%), followed by CNS (44.4%). The median number of prior therapies was 2 (1 – 8). Pembrolizumab was the most used prior IO (87%), followed by durvalumab (10.7%) and nivolumab (8.3%). 13.6% (n = 23), 49.1% (n = 83), and 37.2% (n = 63) patients received subsequent Atezo, Doce, and Doce+Ram, respectively. PFS was improved in the Atezo group compared with Doce group (median PFS 3.9 vs. 3.7 months, HR 0.57, 95% CI 0.37 – 0.87, p = 0.015*). Notably, a prominent percentage of patients in the Atezo group appear to have long-term PFS benefits, demonstrated by 1-year PFS rates of 26.1%, 3.6%, and 4.8% (p = 0.003**), and 2-year PFS rates of 17.4%, 0%, and 0% (p = 0.002**), in the Atezo, Doce, and Doce+Ram groups, respectively. The median OS (months) in the Atezo, Doce, and Doce+Ram groups were 17.5, 7.6, and 11.5, respectively; and were 29.5, 7.2, and 6.9, respectively in the PD-L1 > 50% subgroups. The Atezo group showed significantly greater OS improvement compared with the Doce group (HR 0.42, 95% CI 0.26 – 0.66, p = 0.001**). This benefit appears greater and remains statistically significant in the PD-L1 > 1% (HR 0.39, 95% CI 0.22 – 0.71, p = 0.005**) and PD-L1 > 50% (HR 0.37, 95% CI 0.15 – 0.91, p = 0.022*) subgroups. 5 of 23 (21.7%) patients in the Atezo group developed immune-related adverse events. 3 patients were grade 3 or 4. No grade 5 event. Conclusions: We observed statistically significant and clinically meaningful PFS and OS benefits of atezolizumab monotherapy compared with docetaxel in patients with advanced NSCLC who were pretreated with IO. The OS benefits of atezolizumab over docetaxel +/- ramucirumab was greater in PD-L1 > 1% and PD-L1 > 50% subgroups. Atezolizumab appears to be tolerable in IO-pretreated patients. These findings need to be verified in a prospective study.

e21156 Background: Immunotherapy (IO) is one of the major treatments for patients with metastatic non-small cell lung cancer (mNSCLC). IO may be discontinued in patients for many reasons, the most common being progression of disease (POD). For those patients who discontinued IO for reasons other than POD, such as immune-related adverse event (irAE), there is limited data that compare progression-free survival (PFS) and overall survival (OS) when IO is continued vs. stopped. Methods: We conducted a retrospective study of all patients with mNSCLC (stage IV) treated with IO at our institution from 2011 to 2022. Patients who discontinued IO due to POD were excluded from the analysis. The clinical outcomes, including PFS, OS, and irAE were investigated among patients with no POD who stopped IO prior to 6 or 12 months (m) vs. those that continued IO > 6 or 12m. Results: The analysis at the 6m timepoint included 92 patients, 82.6% were white, 50% were male, 67.4% had adenocarcinoma, and 82.6% used tobacco. The most common site of metastasis was bone (28.3%), followed by CNS (20.7%). 51.2% of patients had received IO as the first line systemic therapy and 32.6% received it as their second. Pembrolizumab was the most used IO (84.78%). Among these patients, 25 discontinued IO before 6m, and 67 patients continued IO beyond 6m. irAE, of any grade, occurred in 44.0% vs 37.3% when comparing IO discontinued with IO continued group at 6m. Patients who continued treatment beyond 6m had a longer duration of PFS (22.8m vs 11.8m, p = 1.14E-04) with a significant increase in OS (34.5m vs 14.0m, p = 1.34E-07). The analysis at the 12m timepoint included 71 patients, 87.3% were white, 46.5% were male, 78.9% had adenocarcinoma, and 80.3% used tobacco. The most common site of metastasis was bone (29.9%), followed by CNS (22.5%). 62.0% of patients had received IO as the first line systemic therapy and 28.7% received it as their second. Pembrolizumab was the most used IO (87.3%). Among these patients, 30 discontinued IO before 12m, and 41 patients continued IO beyond 12m. irAE, of any grade, occurred in 36.7% vs 41.5% when comparing IO discontinued with IO continued group at 12m. Similarly, patients who continued treatment beyond 12m had a longer duration of PFS (28.4m vs 14.2m, p = 1.91E-06) with a significant increase in OS (39.9m vs 17.6m, p = 3.45E-09). Conclusions: We observed that patients with mNSCLC and no POD, who continued IO beyond 6m and 12m, experienced a significant increase in PFS and OS than those who discontinued IO, with more significant increases in those who continued IO past 12m. These findings need to be verified in a larger cohort.

e21118 Background: Leptomeningeal metastasis (LM) is a debilitating condition associated with advanced non-small cell lung cancer (NSCLC). When driver mutations in the epidermal growth factor receptor (EGFR) are identified, targeted therapies (TT) represent an appealing therapeutic strategy. However, the efficacy of TT for LM is unknown as LM patients are routinely omitted from clinical trials. Methods: We conducted a systematic review and meta-analysis of individual patient data to evaluate the efficacy of EGFR TT in EGFR-mutant NSCLC LM in accordance with PRISMA guidelines. EGFR-TTs evaluated were erlotinib, gefitinib, icotinib, afatinib, dacomitinib, osimertinib, zorifertinib, and furmonertinib. The co-primary endpoints were progression-free survival (PFS) and overall survival (OS). To assess differences between groups, shared frailty Cox regression models were used to estimate the hazard ratio (HR), 95% confidence interval (CI) and p-value. Results: 7780 abstracts were screened, identifying 126 publications with 232 patients, corresponding to 272 lines of EGFR-TT for NSCLC LM which met inclusion criteria. The overall median PFS (mPFS) in patients receiving any EGFR-TT was 9.15 months and the median overall survival was 14.5 months. In univariable analyses, osimertinib was associated prolonged PFS compared to other EGFR-TT, (mPFS of 11 versus 8 months, HR = 0.64; 95% CI: 0.44-0.93; P = 0.02). Osimertinib was numerically associated with prolonged OS compared to other EGFR-TT (mOS 16.8 months versus 13.6 months, HR = 0.72; 95% CI 0.44-1.17, P = 0.188). In multivariable analyses, ECOG performance status > 2 was independently associated with shortened PFS (mPFS 10 versus 8 months, HR = 1.54, 95% CI: 1.26-3.04; P < 0.05) and OS (mOS 16.5 versus 10 months, HR = 3.33, 95% CI: 1.80-6.18; P < 0.05). Conclusions: In the largest cohort of NSCLC LM treated with EGFR TT compiled to date, osimertinib is associated with marginally improved outcomes compared to other EGFR TTs. ECOG performance status is an independent predictor of prognosis in these patients. These results highlight the need for prospective studies for this difficult to treat patient population.

e21030 Background: Docetaxel +/- ramucirumab remains the standard of care therapy after progression on platinum doublet and immune checkpoint blockade (ICB) in patients with metastatic non-small cell lung cancer (NSCLC). However, the clinical benefit from docetaxel is short-lived with substantial toxicity. Additionally, whether cancer gene mutation status impacts the benefit from docetaxel has not been systemically studied. In this real-world study, we aim to investigate whether cancer gene mutation status is associated with benefit from docetaxel. We also explored whether IMPOWER150-based regimens (ABCP-atezolizumab + bevacizumab + carboplatin + paclitaxel; ACP-atezolizumab + carboplatin + paclitaxel; BCP-bevacizumab + carboplatin+paclitaxel) may serve as alternative options with better efficacy in this patient population. Methods: We retrospectively queried MD Anderson Cancer Center GEMINI database for patients with metastatic NSCLC who received docetaxel, docetaxel+ramucirumab, or one of the above-mentioned IMPOWER150-based regimens after progression on concomitant or sequential platinum-doublet and ICI. Primary endpoints include progression-free survival (PFS) and overall survival (OS). Results: 274 patients were analyzed (docetaxel n = 99; docetaxel +ramucirumab n = 142; ABCP n = 28; BCP n = 4, ACP n = 1). No significant difference was observed in mPFS (3.00m versus 3.93m, P = 0.156) or mOS (8.40m vs.8.67m, P = 0.737) between patients from docetaxel monotherapy group and docetaxel+ ramucirumab group. Cancer gene mutations in EGFR, KRAS, TP53 or PD-L1 expression (0-1%; 1-49%; ≥50%) were not associated with PFS or OS in the 241 patients treated with docetaxel +/- ramucirumab. Furthermore, there was no difference in mPFS (5.50m versus 3.47m, P = 0.516) or mOS (10.40m versus 8.83m, P = 0.737) in patients who received IMPOWER 150-based regimens compared to those who were treated with docetaxel+/- ramucirumab. The median treatment duration was 1.60m (0.70m-20.23m), 1.90m (0.70m-32.90m), 4.80m(0.70m-33.47m) and 11 patients (11.11%), 20 patients (14.08%), and 3 patients (9.09%) discontinued treatment due to adverse events in the patients treated with docetaxel monotherapy, docetaxel+ramucirumab combined therapy, and the IMPOWER150 regimens, respectively. Conclusions: These results from this real-world study suggested that unlike for ICI therapy, where onco-driver mutations have profound impact on the clinical benefit, the cancer gene mutation status does not impact the benefit from docetaxel +/- ramucirumab in NSCLC patients who progressed on platinum doublets and ICI. Furthermore, the clinical benefit from docetaxel +/- ramucirumab is short-lived. Novel treatment regimens are urgently needed in this clinical setting.

TPS9162 Background: Immune checkpoint inhibitors (ICI) are a standard of care (SOC) treatment that have improved outcomes for patients (pts) with non-small cell lung cancer (NSCLC). However, most pts progress, signaling a need for combination approaches to further improve outcomes. CAN-2409 is a replication-defective adenoviral construct encoding the herpes simplex virus thymidine kinase (HSV-tk) gene that is injected intratumorally followed by 2 weeks of prodrug (valacyclovir or acyclovir). HSV-tk converts the prodrug in the tumor microenvironment into a toxic metabolite, resulting in immunogenic cell death, while the adenoviral proteins provide a strong pro-inflammatory signal. Together, this leads to in situ vaccination against the patient’s own tumor. As a result, CD8+ cytotoxic T cells are educated on how to recognize and kill tumor cells in both the injected tumor and the uninjected metastases. A completed neoadjuvant phase I trial in resectable NSCLC demonstrated safety and immune stimulation (Predina et al 2021), warranting further investigation of CAN-2409 + prodrug as a therapy that can lead to improved long-term outcomes for pts with NSCLC who have a suboptimal response to ICI. Methods: LuTK02 (NCT04495153) is an open-label, multi-arm, phase II clinical trial to evaluate CAN-2409 + prodrug added to SOC ICI (anti-PD-(L)1) therapy in pts with stage III/IV NSCLC presenting with inadequate response (as defined below) to ICI. Cohort 1 includes pts with nonresponding but stable disease ≥18 weeks after starting ICI; cohort 2 includes pts with progressive disease ≥18 weeks after starting ICI. Key eligibility criteria include RECIST-evaluable disease; an injectable lesion (via bronchoscopy or US/IR guidance); ability to continue ICI for the treatment period; no change of ICI or prior interruptions of > 4 weeks within 6 months of enrollment; and no focal therapy at > 3 sites of disease within 12 months prior to enrollment. Key exclusion criteria include a history of ICI immune-related adverse events and known alterations in EGFR, ALK, or ROS1. Eligible patients receive 2 injections of CAN-2409 approximately 6 weeks apart followed by prodrug for 14 days. After treatment of ~40 evaluable pts in cohort 2 with two injections of CAN-2409, the protocol has been amended to include a new cohort (n~20) of pts treated with three injections of CAN-2409 approximately 4 weeks apart, each followed by prodrug for 14 days, to further define the optimal therapeutic regimen. Primary endpoints are overall response and/or disease control rate per RECIST 1.1 criteria and safety of CAN-2409 + prodrug. Secondary endpoints include duration of response, PFS, OS, and biomarker studies. Exploratory endpoints include evaluation of effects in non-injected lesions, changes in non-target (per RECIST) lesions, tumor growth trajectory, and viral shedding. Clinical trial information: NCT04495153 .

9122 Background: Initial treatment selection for advanced NSCLC patients without driver mutations is mainly based on evaluating PD-L1 expression levels in the tumor tissue. However, PD-L1 assays are only moderately predictive. In addition, the guidelines for the PD-L1≥50% subpopulation are not definitive, enabling the usage of immune checkpoint inhibitors (ICI) either as a monotherapy or combined with chemotherapy. Here we aim to provide a decision-making tool for the first-line treatment of advanced NSCLC patients based on plasma derived biomarkers obtained before treatment initiation. Methods: Pre-treatment plasma samples were collected from 545 NSCLC patients receiving ICI-based therapy. Clinical benefit was evaluated based on progression-free survival (PFS) at 12 months as a threshold. Deep plasma proteomic profiling was performed using aptamer technology. Based on the proteomic profiles, a computational model, termed PROphet, was developed and evaluated in a blinded manner on the validation subset (n = 272). The model output, clinical benefit probability, was used to stratify the patients into two groups, PROphet-positive or -negative. Results: The model displayed good performance with a high correlation between the predicted clinical benefit and the observed clinical benefit rate (R2= 0.97), outperforming a PD-L1-based prediction model (R2= 0.35). Patients classified as PROphet-positive achieved significantly longer overall survival (OS) than PROphet-negative patients, with a median OS of 25.9 versus 10.8 months (hazard ratio, HR = 0.51; 95% confidence interval, CI = 0.37-0.70; p-value < 0.001). Next, we examined the clinical utility of combining the PROphet output with PD-L1 levels by comparing different treatment modalities. Focusing on PD-L1≥50%, patients with PROphet-positive results displayed similar OS and PFS when receiving ICI monotherapy or ICI-chemotherapy (OS HR = 0.77; CI = 0.42-1.43; p-value = 0.4096), suggesting that these patients may consider monotherapy, thus avoiding chemotherapy-related toxicity. Conversely, PD-L1≥50% patients with a PROphet-negative result displayed a significantly longer OS and PFS when receiving ICI-chemotherapy in comparison to ICI monotherapy, with a median OS that was not reached versus 11.10 months in the combination therapy and monotherapy groups, respectively (HR = 0.29; CI = 0.14-0.59; p-value < 0.001). These patients should consider combination therapy, avoiding a treatment that is suboptimal for them. Results for PD-L1 1-49% and < 1% provide additional clinical information for each subgroup. Conclusions: Plasma proteomic profiling can provide biomarkers that accurately predict the benefit of ICI-based treatment. The model output complements tissue PD-L1 expression levels as a tool to assist therapeutic decisions.

9093 Background: Pembrolizumab interrupts PD-1/-L1 interaction and is efficacious in many cancers. However, resistance invariably emerges in the majority of patients. Potential mechanisms include activation of compensatory pathways. The inhibition of sonic hedgehog signaling (sHH) was previously shown to induce intra-tumoral (IT) infiltration by CD4+, CD8+ and HLA-DR class II cells. Our preclinical data showed sHH inhibitor enhanced IT penetration by monoclonal antibodies and induced PD-L1 expression. We conducted a phase I study using a novel sequential pulse dosing of sonedegib followed by pembrolizumab in aST with an expansion cohort to determine the maximum tolerated dose (MTD), tolerability and preliminary efficacy. Methods: The dose escalation utilized a 3+3 design to determine the MTD and proceeded to expansion cohort upon determination of the MTD. Patients enrolled to each dose level were observed for dose limiting toxicities (DLTs) during the 1st cycle. The expansion cohort consisted of NSCLC and head/neck squamous cell carcinoma (HNSCC) previously treated by anti-PD1/-L1. The recommended phase 2 dose (RP2D) was determined following the review of the toxicity profile of the combination from all cycles. The study treatment consisted of sonidegib oral daily from day 1 to 8 and pembrolizumab I.V. 200 mg on day 8 on an every 3-week cycle. The sonidegib dose levels explored were 400, 600 and 800 mg. Archival tumor and blood specimens were collected for correlative studies. Adverse events (AEs) were categorized and graded per CTCAE v5.0, and tumor response by RECIST v1.1. Results: The study enrolled a total of 33 patients and 29 received treatment (13 in escalation and 16 in expansion), including patients with NSCLC, HNSCC, skin cancer, gastric cancer and melanoma. The enrollment to the NSCLC cohort is complete and HNSCC continues. No DLT was encountered during dose escalation and the MTD was not reached. The highest planned dose level was selected to proceed to expansion (sonidegib 800mg days 1-8 in combination with pembrolizumab I.V. 200 mg on day 8 on an every 3-week cycle). The expansion cohort proceeded to enroll 15 patients evaluable for AEs (10 NSCLC and 5 HSNCC). Grade 3 and above treatment-related AEs across all patients were hyperglycemia, fatigue, dyspepsia, abdominal pain. The mature efficacy data will be reported at the meeting. Conclusions: The study successfully determined the RP2D of sonidegib when dosed sequentially with pembrolizumab in advanced solid tumors. The AE profile of the combination is similar to that for respective agents given individually. The efficacy data among anti-PD1/-PDL1-treated NSCLC will be reported at the meeting. Clinical trial information: NCT04007744 .

9091 Background: Biomarker testing, including for rearrangement during transfection (RET), is recommended and important in selecting efficacious targeted therapy for patients with advanced non-small cell lung cancer (aNSCLC). This retrospective cohort study characterized RET testing and treatment patterns among aNSCLC patients in clinical practice. Methods: We used the nationwide Flatiron Health electronic health record-derived de-identified database to select patients diagnosed with aNSCLC (stage ≥IIIB) from 2017-2022. We measured rates of RET testing (test result ≤90 days after advanced diagnosis). We used logistic regression to identify baseline characteristics predictive of timely testing. Finally, we described treatment patterns for patients with RET+ aNSCLC before and after the US approval of RET inhibitors. Results: Among 26,329 aNSCLC patients, rates of RET testing ≤90 days after advanced diagnosis increased from 25% (2017 Q1) to 73% (2022 Q1). Patients were less likely to receive RET testing within 90 days if they were Black (multivariate odds ratio [OR] 0.8) or Hispanic (OR 0.8) compared to White, or had Medicare (OR 0.9; all p<0.001) compared to commercial insurance. Patients were more likely to receive RET testing within 90 days if they were in the highest socioeconomic quintile (OR 1.4), had de novo disease (OR 2.1), or no history of smoking (OR 1.3; all p<0.001). Between 2017 and 2022, there were increases in the use of next-generation sequencing (66% to 89%) and blood samples for biomarker testing (25% to 49%) and a decrease in mean days from diagnosis to test result (33 to 28) for the first RET test among those who had testing within 90 days. Among all patients with aNSCLC tested within 90 days (n=12,275), 73 were RET+ and received 1L treatment ≤90 days after advanced diagnosis. The most common 1L treatments before (n=35) and after (n=38) RET inhibitor approval were chemotherapy (40%) and RET inhibitor (42%), respectively (Table). Conclusions: RET testing has increased over time, but certain patient subgroups are less likely to receive timely RET testing and therefore may not be optimally treated. Among patients with RET+ aNSCLC identified after RET inhibitor approval, only 42% were treated with a RET inhibitor in the 1L setting. These results suggest both disparities in access to RET testing and unmet medical need among patients with RET+ aNSCLC. [Table: see text]

9069 Background: With the emergence of effective targeted-therapies for KRAS G12C, and the development of promising agents for KRAS G12V and G12D among others, the identity of unique KRAS mutations in non-small cell lung cancer (NSCLC) has become increasingly relevant. Acquired KRAS mutations are a known mechanism of resistance observed across driver mutation-positive (DM+) NSCLC. The incidence and diversity of these acquired alterations, and whether they differ from those observed in de novo KRAS-mutated NSCLC, is unknown. Methods: NSCLC molecular profiles were obtained using next-generation sequencing (Caris Life Sciences) with paired whole-transcriptomic sequencing (Illumina NovaSeq) and immunohistochemistry (Caris Life Sciences). Demographic data were abstracted from medical records. KRAS mutation diversity was defined for de novo KRAS-mutated ( KRASmt) NSCLC ( KRAS as only identified driver – KRASmt_dn) and DM+ NSCLC with acquired KRAS mutations (concurrent KRASmt with other known driver – KRASmt_acq). Fisher’s exact test was used to compare the distribution of unique KRAS mutations between the groups. Due to the unique biology of NSCLC with class II/III BRAF mutations, this subset was removed from the KRASmt_acq subgroup for the final analysis. Results: A total of 5932 KRASmt NSCLC samples were identified, among which 5879 were KRASmt_dn and 53 were KRASmt_acq (see table). The distribution of unique KRAS mutations was not significantly different between groups (p = 0.14). Within the KRASmt_dn group, KRAS G12C was most common (40%), followed by G12V (19%), G12D (14%), G12A (7%) and Q61H/G13C (4% each). In the KRASmt_acq group, KRAS G12C was most common (30%), followed by G12D (19%), G12V (17%), Q61H (11%), G12A (7%), and G13C (6%). The most common observed driver mutations in the KRASmt_acq group were EGFR (38%) and MET (30%). In the EGFR group, KRAS G12D (25%), Q61H/G12C (20% each), G12V/G13C (10% each), and G12F/A/R (5% each) were observed. In the MET group, KRAS G12C (25%), G12D/V/A (19% each), Q61H (12%) and G12S (6%) were seen. Among 7 patients with a documented history of smoking in the KRASmt_acq group, KRAS G12D and Q61H were most common (29% each), followed by G12V/F and G13C (14% each). Conclusions: While the distribution of unique KRAS mutations did not differ significantly between KRASmt_dn and KRASmt_acq groups, acquired KRAS mutations were seen across DM+ NSCLC subsets, among which the frequency of observed mutations appeared to vary. The functional and immunological significance of these mutations, and their impact on clinical outcomes, warrants further investigation. [Table: see text]