All treatment-emergent adverse events

Abstract Background: Immune checkpoint inhibition (ICI) is a front-line standard-of-care treatment for patients with metastatic melanoma (MM). However, there are critical questions pertaining to optimal ICI management, particularly the ideal duration of therapy, for which biomarker guidance is lacking. Identifying patients who are safely able to receive a shorter course of ICI (<2 years), thereby limiting physical and financial toxicity, is an unmet need. In this non-randomized, prospective interventional trial (NCT06146920) we evaluated the use of the FDA-approved companion diagnostic test, FoundationOne®CDx (F1CDx), and the laboratory developed test FoundationOne®Tracker, a tissue-informed personalized ctDNA monitoring assay, as an efficacy metric to guide treatment discontinuation. Methods: Eligible patients had radiographic evidence of disease control (stable disease or response) on ICI (>12 months but ≤18 months) without the development of dose-limiting immune-related adverse event/s (irAEs). After successful sequencing with F1CDx, the FoundationOne Tracker assay was generated. Patients ctDNA positive were excluded. The ctDNA negative (neg) patients stopped ICI and continued with active surveillance, including standard of care imaging as well as serial ctDNA via FoundationOne Tracker at 1month, 2month, 3month and subsequently every 3months up to 1 year. Patients were followed for an additional year to monitor for recurrence. The primary endpoint was PFS 12-month post-ICI cessation. Results: From March 2024 through September 2024, 12 patients with MM were screened with two becoming ineligible due to development of an irAE prior to ICI cessation and one due to inadequate tissue for F1CDx. Of enrolled patients (n=9), six had cutaneous MM, one mucosal MM and two with MM from an unknown primary. ICI regimens included nivolumab-relatlimab (n=5), ipilimumab-nivolumab (n=2) and pembrolizumab (n=3) with a median duration on therapy of 13.9 mths. The best radiographic response prior to ICI cessation was Partial Response in 6, Complete Response in 3; in those who underwent PET imaging (n=6), 3 had a complete metabolic response (CMR), and 3 had a near-CMR. All patients remained ctDNA neg at 12months post-ICI cessation and after a median of 14.9 months (13.4-19.2) following enrollment, all patients remain ctDNA neg with no clinical or radiographic evidence of progression. Conclusion: ctDNA guided therapy decisions for advanced cancers is an active area under clinical investigation. To our knowledge, this is the first interventional study utilizing ctDNA to discontinue immunotherapy in patients with MM. Although this study was halted early due to programmatic decisions by the sponsor, the data from this small cohort highlights the potential benefit of ctDNA in guiding treatment discontinuation; further prospective study is needed. Citation Format: Meghan J. Mooradian, Aleigha Lawless, Julianne Czapla, Amaya Gasco, Patrick Boyle, Merrida Childress, Ryan J. Sullivan. Serial plasma tumor-informed next generation sequencing as a new efficacy metric to guide immunotherapy treatment discontinuation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 5261.

Overview plot of patients with stage IIIA melanoma.

TPS2677 Background: Nivolumab/ipilimumab is standard of care for advanced melanoma patients based on Phase III randomized data from the CheckMate 067 trial. The recent 10-year outcomes results were reported with a melanoma specific survival for Nivolumab/ipilimumab of 52%. These data are very encouraging, but 50% of patients still succumb to their disease by 10-years. Preclinical data suggests that the circadian rhythm may influence the anatomic localization, function and activity of T cells, the target of immunotherapy. More T cells in the tumor or tumor-draining lymph node during initial immunotherapy administration may improve clinical responses and long-term outcomes. To investigate this idea, we performed a retrospective analysis, the MEMOIR study, finding that more evening infusions of immunotherapy were associated with significantly worse progression free and overall survival for metastatic melanoma patients. These findings have now been reproduced in other cancer histologies, in a larger meta-analysis, and in pre-clinical mechanistic studies. Considering these data, we hypothesize that evening infusions of immunotherapy will have worse progression free survival than either morning or midday infusions. Methods: The TIME trial is a three-arm phase II study of time-of-day specified administration of standard dose nivolumab/ipilimumab for metastatic melanoma. For newly diagnosed metastatic melanoma patients enrolled on study, they will be randomized to receive 4 cycles every 3 weeks of nivolumab/ipilimumab between 8:00-11:00 (Arm A), 11:00-14:00 (Arm B), or 14:00-17:00 (Arm C). Following these 4 cycles, they will receive standard of care maintenance nivolumab in a time-of-day agnostic fashion. Eligible patients must have stage IV unresectable cutaneous, acral or mucosal melanoma, no prior immunotherapy within 1 year, ECOG performance status of 0-1, age ≥ 18, no symptomatic or hemorrhagic brain metastases with none greater than 2 cm. The primary objective is to determine whether progression free survival for Arm A or Arm B is superior to Arm C. Secondary objectives include assessments of adverse events, melanoma specific survival and overall survival. We will evaluate the immune profiles of blood and tumor to assess the impact of time of drug administration on the circulating immune responses and the tumor immune microenvironment. 99 patients will be enrolled to detect a HR of 0.50 with at least 80% power and a Type 1 error rate of 0.1 (2-sided) for a comparison of A vs. C, and B vs. C. The study is open at Emory and has enrolled 3 patients; the study is undergoing regulatory review at MGH and Cedars-Sinai. Clinical trial information: NCT07155317 .

9529 Background: Molecular imaging plays a critical role in assessing immunotherapy response in metastatic melanoma, but current assessment methods may not fully leverage imaging data to inform clinical decision-making. This study prospectively evaluated whether integrating TRAQinform Immuno quantitative analysis into clinical assessment would alter oncologists' treatment intent in metastatic melanoma patients receiving checkpoint inhibitor combinations. Methods: In this prospective, multisite, non-interventional study (NCT05819255), patients with metastatic melanoma receiving dual-agent immunotherapy were enrolled at the University of Wisconsin Carbone Cancer Center and Massachusetts General Hospital Cancer Center. FDG PET/CT scans were acquired at baseline, 3-4 weeks and 12 weeks. All scans were analyzed using a research version of the TRAQinform IQ (TRAQinform) algorithmic quantitative software. At each timepoint, treating oncology and nuclear medicine teams recorded treatment intent before and after review of the TRAQinform analysis report. A cross-site, blinded review was conducted to assess potential status quo bias. Results: Twenty-six patients were enrolled (12F, 14M, mean age 65 years), 25 of whom completed all study scans. At week 3-4, 27% of cases (7/26) showed an intent to change treatment after oncologists reviewed the TRAQinform report, (p=1.0). At the 12-week assessment, 56% of cases (14/25) demonstrated intent to change treatment (p=0.0008). Considering either timepoint, 65% of cases (17/26) exhibited a change in treatment intent compared to baseline (p=0.000006). Cross-site analysis indicated minimal influence of status quo bias on intent decisions. Conclusions: In this prospective study assessing intent to treat, TRAQinform analysis of standard-of-care FDG PET/CT images influenced oncologists treatment decision in the majority of metastatic melanoma patients, suggesting it provides clinically actionable information. For oncologists managing patients on dual-agent immunotherapy - where treatment decisions often involve uncertainty and clinical judgment, this study demonstrates that TRAQinform offers an additional data-driven tool to support optimal therapeutic decision-making. Research reported in this abstract was supported by the National Cancer Institute of the National Institutes of Health and under Award Number R44CA257253. The content is solely the responsibility of the authors and does not necessarily represent the official news of the National Institutes of Health. Clinical trial information: NCT05819255 .

A, Kaplan–Meier RFS curves stratified by ctDNA status among patients who received adjuvant systemic therapy. Anytime ctDNA positivity was associated with significantly inferior RFS. B, Kaplan–Meier RFS curves stratified by ctDNA status among patients who did not receive adjuvant therapy, showing a similar strong association between ctDNA positivity and recurrence. C, Sankey diagram illustrating ctDNA dynamics after systemic therapy initiation among 53 patients with ≥1 on-treatment ctDNA timepoint. Of the 8 patients who recurred, 2 exhibited persistent ctDNA positivity or converted from ctDNA-negative to ctDNA-positive despite treatment. A subset demonstrated transient clearance before recurrence.

Overview plot of patients with stage IIB melanoma.

9564 Background: Intismeran autogene (intismeran) is an individualized mRNA-based neoantigen (neoAg) therapy designed to enhance endogenous antitumor T-cell responses by targeting patient-specific tumor mutations. In the phase 2 KEYNOTE-942 trial of resected high-risk melanoma, intismeran combined with pembrolizumab (pembro) significantly improved recurrence-free survival (RFS) vs pembro alone. Previously, it was shown that the combination induced greater expansion of de novo T-cell clonotypes, which correlated with RFS in the intismeran arm. Here, we show that de novo T-cell clonotypes are reactive to intismeran-encoded neoAgs. Methods: Peripheral leukapheresis samples longitudinally collected from a subset of intismeran plus pembro treated participants (pts) with melanoma from phase 1 and 2 studies (NCT3313778 and NCT03897881) were assessed at single-cell level to characterize neoAg-specific T cells. In 7 pts, functional assessment of neoAg-reactive CD8⁺ T cells was performed by intracellular cytokine staining and activation-induced marker assays. To define antigen specificity and phenotype of intismeran-induced T cells, we combined longitudinal bulk and single-cell T-cell receptor (TCR) sequencing with functional validation assays from 3 pts. De novo expanded TCRs were tested in Jurkat NFAT-luciferase reporter cells for reactivity against pt-specific intismeran mRNA cassettes and individual neoAgs. For reactive TCRs, minimal epitopes were mapped and mutant vs wild-type peptide reactivity was quantified. Results: Using the combination of bulk and single-cell TCR sequencing and Jurkat NFAT-luciferase reporter assays in 3 pts, we identified 20 TCRs expanded following intismeran therapy across all pts mapping to 11 neoAgs, providing direct evidence of intismeran-driven polyclonal T-cell expansion. These responses targeted multiple neoAgs with persistence >100 days after last intismeran dose. Reactive TCRs showed stronger recognition of mutant vs wild-type peptides, confirming antigen specificity. Functional assessment of T cells from 7 pts showed that neoAg-reactive CD8⁺ T cells secreted IFNγ and TNFα and coexpressed markers for degranulation/activation upon peptide restimulation, demonstrating functional activity. Flow cytometry–based characterization of neoAg-reactive T cells ex vivo revealed that these cells predominantly exhibited an effector-memory phenotype. Upon stimulation, they were polyfunctional (IFNγ⁺ TNFα⁺), mobilized CD107a, and were granzyme B⁺, consistent with cytotoxic effector function relevant to tumor control. Conclusions: Complementary sequencing and functional analyses demonstrated that adjuvant therapy with intismeran plus pembro induced durable, polyclonal, neoAg-specific T-cell responses with effector-memory characteristics, providing mechanistic data consistent with the clinical benefit observed in pts with melanoma. Clinical trial information: NCT3313778 & NCT03897881 .

Abstract There are currently no effective targeted therapies for BRAF-mutant metastatic melanoma patients with acquired resistance to approved BRAF and MEK inhibitors (BRAFi and MEKi), and very few ongoing clinical trials. Anti-apoptotic BCL2 family proteins promote de novo resistance to several therapies, including single-agent BRAFi in BRAF-mutant melanomas. In this study, in vivo testing of a large collection of patient-derived xenograft (PDX) models from melanoma patients with acquired resistance to BRAFi or BRAFi+MEKi shows that combining BCL2 inhibitors (BCL2i; navitoclax or venetoclax) with BRAFi+MEKi induces tumor regressions in a subset of these PDXs. High basal BCL2 predicts response whereas high basal MCL1 predicts resistance to this strategy. MCL1 overexpression studies functionally validate its role in resistance. Further, combining BRAFi+MEKi with an MCL1 inhibitor (MCL1i) counteracts resistance and interestingly decreases MCL1i-associated markers of cardiotoxicity. Together these studies identify potential personalized strategies to improve outcomes in this challenging patient population.

Change in peripheral blood cytokines. Panel A shows the median change from baseline in peripheral blood cytokine concentration over time by dose of mRNA-2752 in Arm A and Arm B, and panel B shows cytokine fold change relative to C1D1 over time by dose of mRNA-2752 in Arm A and Arm B. Data are shown from samples from 125 patients. C1D1, cycle 1 day 1; IFN-γ, interferon gamma; IL, interleukin; IP-10, IFN-γ–induced protein 10; MCP-1, monocyte chemoattractant protein 1.

Taxonomic differences from baseline between treatment arms at after antibiotic preconditioning and at C1D1

Overview plot of patients with stage IA/B melanoma.

BACKGROUND:Programmed death receptor 1 (PD-1) blockade produces high response rates in resectable and locally advanced cutaneous squamous cell carcinoma (CSCC), but how many doses are needed and whether surgery or radiation after immunotherapy (consolidation) adds benefit in deep responders (patients with substantial clinical responses) remain unclear. Observational inference is challenging because treatment decisions are response-guided, doses accumulate over time, and treatment selection depends on patient characteristics that also affect outcomes. METHODS:We conducted a retrospective cohort study of 189 patients with resectable, borderline-resectable, locally advanced, or limited metastatic CSCC treated with immune checkpoint inhibitors as part of management (2019-2025). We summarized responses, treatment discontinuation patterns, and time-to-event outcomes. To evaluate dose-response relationships, we fit Bayesian regression models adjusting for prespecified baseline confounders. Directed acyclic graphs were used to formalize causal assumptions and identify minimally sufficient adjustment sets. For event-free survival (EFS), we used a prespecified landmark analysis among patients receiving ≥2 doses to reduce guarantee-time bias. RESULTS:Objective response occurred in 119/189 (63%), including 52/189 (27.5%) complete responses. Nearly half of patients received ≤2 doses (92/189, 48.7%). Among 50 complete responders managed without surgery, 1 recurrence was observed over a median follow-up of 25.4 months. Dose-response models showed a consistent but modest positive association between additional doses and response: in a linear model, each additional dose was associated with ~1.09 fold higher odds of response (posterior probability >95%). Flexible threshold models suggested early concentration of benefit, strongest at 2 versus 1 dose (93.6% posterior probability of benefit), with persistent uncertainty in effect magnitude (66% probability of ≥6 percentage-point absolute increase). In the EFS landmark modeling cohort (n=177), receipt of ≥3 versus 2 doses showed a 93% posterior probability of reduced event risk, but the 89% credible interval spanned the null (HR 0.61-1.01), indicating substantial uncertainty regarding incremental downstream benefit. CONCLUSIONS:In real-world CSCC, durable disease control frequently occurred after limited immunotherapy exposure, and clinical responders often did well without routine surgical consolidation. Although additional doses may modestly improve outcomes, observed gains appear concentrated early with uncertain incremental value beyond two doses. These patterns support conceptualizing treatment as frontline immunotherapy with response-guided subsequent treatment rather than fixed-duration neoadjuvant therapy.

Over the past decade, the development and implementation of novel circulating tumor "liquid biopsies" in clinical practice has revolutionized cancer care. These tools provide sensitive and specific analysis of tumor status which enable non-invasive alternatives to tissue biopsy for real-time tumor monitoring, guided targeted therapy, predicted treatment response, and assessing therapeutic resistance and residual disease. The FDA has already approved several assays to detect genetic alterations in plasma cell-free DNA for use as companion diagnostics matched to specific molecularly targeted therapies for cancer, setting the stage for future use in early relapse detection and additional applications which are expected to be incorporated into standard-of-care practices for aggressive cutaneous malignancies. It will therefore be important for the dermatology community to have a working knowledge of liquid biopsy techniques and their relevance to the management of cutaneous malignancies. This review highlights state-of-the-art liquid biopsy tools currently in practice with an emphasis on the development and implementation of circulating biomarkers in skin cancers. It is anticipated that liquid biopsy tools will soon become integrated into evolving standards-of-care for improved management of patients with aggressive cutaneous malignancies.

CD8 intra-tumoral infiltration percentage by IHC

Representativeness of the Study Population.

9510 Background: Although acute toxicities associated with adoptive cellular therapy using lifileucel are well described and largely occur within the first 2 weeks of treatment, adverse events beyond this early window remain incompletely characterized. We sought to characterize treatment-related adverse events (AEs) with emphasis on those starting or persisting ≥2 weeks after lifileucel infusion. Methods: We conducted a retrospective multicenter study across three centers (Moffitt Cancer Center, Massachusetts General Hospital, and Mayo Clinic). Patients with advanced melanoma treated with lifileucel were included. The primary endpoint was incidence and characterization of AEs occurring or persisting ≥2 weeks after standard of care lifileucel infusion. Results: Among 79 patients (median follow-up 11 months [95% CI, 9.6–15]), median age was 63 years (range 30–79), 59% were male (n = 47), 41% were female (n = 32), and ECOG PS was 0–1 in 98%. Patients received a median of 5 IL-2 doses (range 0–6). Of 79 patients, 78 experienced treatment-related adverse events that either persisted or occurred >2 weeks after cell infusion. A total of 308 delayed treatment-related adverse events were identified; 96 were new events (31%) and 212 (69%) were continued toxicities that started < 2 weeks after cell infusion. Lymphopenia was the most common delayed or persistent toxicity, occurring in a majority of patients (n = 68/79, 86%). Treatment-associated anemia (n = 59/79, 75%), fatigue (n = 56/79, 71%) and thrombocytopenia (n = 24/79, 30%) were also common. Viral infections occurred in 9.0% (n = 7), including CMV/EBV viremia (n = 1) and respiratory or gastrointestinal viral infections (metapneumovirus, parainfluenza, SARS-CoV-2, and norovirus). Hemophagocytic lymphohistiocytosis (HLH) occurred in 2 patients (n = 2/79, 3%) and was fatal in both cases. No other toxicity related deaths were noted. Autoimmune toxicities directly attributable to TIL included vitiligo in 9% (n = 7; median onset 41 days), uveitis in 5% (n = 4; median onset 26 days), and sensorineural hearing loss in 1% (n = 1; onset 28 days). All patients underwent TIL infusion in the inpatient setting; a total of 14 of 79 patients (18%) were re-admitted after discharge due to treatment-related toxicity (median time from infusion 19 days). Conclusions: In this multicenter real-world cohort, toxicities persisting beyond two weeks were largely driven by lymphodepleting chemotherapy–associated immunosuppression and cytopenias. These findings highlight the importance of structured post-discharge monitoring and support ongoing efforts to de-intensify lymphodepleting chemotherapy to improve safety while maintaining clinical benefit.

Distribution of lead time between ctDNA detection and imaging-confirmed recurrence using the first ctDNA-positive sample prior to recurrence. Each dot represents an individual patient with green dots representing patients who became ctDNA-positive and whose initial post-positivity imaging remained negative with recurrence confirmed on subsequent imaging.