Fundamental immune-oncogenicity trade-offs define driver mutation fitness.

Missense driver mutations in cancer are concentrated in a few hotspots1. Various mechanisms have been proposed to explain this skew, including biased mutational processes2, phenotypic differences3-6 and immunoediting of neoantigens7,8; however, to our knowledge, no existing model weighs the relative contribution of these features to tumour evolution. We propose a unified theoretical 'free fitness' framework that parsimoniously integrates multimodal genomic, epigenetic, transcriptomic and proteomic data into a biophysical model of the rate-limiting processes underlying the fitness advantage conferred on cancer cells by driver gene mutations. Focusing on TP53, the most mutated gene in cancer1, we present an inference of mutant p53 concentration and demonstrate that TP53 hotspot mutations optimally solve an evolutionary trade-off between oncogenic potential and neoantigen immunogenicity. Our model anticipates patient survival in The Cancer Genome Atlas and patients with lung cancer treated with immunotherapy as well as the age of tumour onset in germline carriers of TP53 variants. The predicted differential immunogenicity between hotspot mutations was validated experimentally in patients with cancer and in a unique large dataset of healthy individuals. Our data indicate that immune selective pressure on TP53 mutations has a smaller role in non-cancerous lesions than in tumours, suggesting that targeted immunotherapy may offer an early prophylactic opportunity for the former. Determining the relative contribution of immunogenicity and oncogenic function to the selective advantage of hotspot mutations thus has important implications for both precision immunotherapies and our understanding of tumour evolution.

Targeting T Cell Co-receptors for Cancer Therapy.

Checkpoint-blocking antibodies can generate potent anti-tumor responses by encouraging the immune system to seek and destroy cancer cells. At this time, the United States Food and Drug Administration has approved three checkpoint-blocking antibodies in three disease indications, and additional approvals are expected to broaden the clinical scope of immunotherapy. Herein, we review the clinical development of CTLA-4-, PD-1-, and PD-L1-blocking antibodies across tumor types and briefly discuss areas of active investigation of potential biomarkers.

Integration of peripheral blood- and tissue-based biomarkers of response to immune checkpoint blockade in urothelial carcinoma.

As predictive biomarkers of response to immune checkpoint inhibitors (ICIs) remain a major unmet clinical need in patients with urothelial carcinoma (UC), we sought to identify tissue-based immune biomarkers of clinical benefit to ICIs using multiplex immunofluorescence and to integrate these findings with previously identified peripheral blood biomarkers of response. Fifty-five pretreatment and 12 paired on-treatment UC specimens were identified from patients treated with nivolumab with or without ipilimumab. Whole tissue sections were stained with a 12-plex mIF panel, including CD8, PD-1/CD279, PD-L1/CD274, CD68, CD3, CD4, FoxP3, TCF1/7, Ki67, LAG-3, MHC-II/HLA-DR, and pancytokeratin+SOX10 to identify over three million cells. Immune tissue densities were compared to progression-free survival (PFS) and best overall response (BOR) by RECIST version 1.1. Correlation coefficients were calculated between tissue-based and circulating immune populations. The frequency of intratumoral CD3+ LAG-3+ cells was higher in responders compared to nonresponders (p = 0.0001). LAG-3+ cellular aggregates were associated with response, including CD3+ LAG-3+ in proximity to CD3+ (p = 0.01). Exploratory multivariate modeling showed an association between intratumoral CD3+ LAG-3+ cells and improved PFS independent of prognostic clinical factors (log HR -7.0; 95% confidence interval [CI] -12.7 to -1.4), as well as established biomarkers predictive of ICI response (log HR -5.0; 95% CI -9.8 to -0.2). Intratumoral LAG-3+ immune cell populations warrant further study as a predictive biomarker of clinical benefit to ICIs. Differences in LAG-3+ lymphocyte populations across the intratumoral and peripheral compartments may provide complementary information that could inform the future development of multimodal composite biomarkers of ICI response. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Decision-Making and Health-Related Quality of Life in Patients with Melanoma Considering Adjuvant Immunotherapy.

BACKGROUND: Adjuvant anti-PD1 treatment improves relapse-free survival (RFS) but has not been shown to improve overall survival (OS) in melanoma and is associated with risks of immune-related adverse events (irAEs), some permanent. We identified factors patients consider in deciding whether to undergo adjuvant anti-PD1 treatment and assessed prospective health-related quality of life (HRQoL), treatment satisfaction, and decisional regret. PATIENTS AND METHODS: Patients with stage IIIB-IV cutaneous melanoma and free of disease, were candidates for adjuvant anti-PD1 immunotherapy, and had not yet discussed adjuvant treatment options with their oncologist were eligible. Participants viewed a 4-minute informational video tailored to their disease stage which communicated comprehensive, quantitative information about the risk of relapse both with and without adjuvant treatment, and risks of each irAE before deciding whether or not to opt for adjuvant therapy. We collected data on demographics, HRQoL, and attitudes toward adjuvant treatment over 1 year. RESULTS: 14/34 patients (41%) opted for adjuvant anti-PD1 immunotherapy, 20/34 (59%) opted for observation. Patients choosing adjuvant immunotherapy scored higher on HRQoL social well-being at pre-treatment, were more likely to endorse positive statements about adjuvant immunotherapy, and to perceive that their physician preferred adjuvant therapy. They had lower decisional regret and higher satisfaction, even if they experienced toxicity or recurrence. CONCLUSIONS: When provided with comprehensive quantitative information about risks and benefits of adjuvant anti-PD1 immunotherapy, 20/34 (59%) of patients opted for observation. Patients choosing adjuvant immunotherapy had lower decisional regret and higher satisfaction over time even if they had poorer outcomes in treatment.

Clinical implications of drug-induced liver injury in early-phase oncology clinical trials.

BACKGROUND: Data on drug-induced liver injury (DILI) and acute liver failure (ALF) in modern phase 1 oncology trials are limited, specifically with respect to the incidence and resolution of DILI and the safety of drug rechallenge. METHODS: This study reviewed all patients who were recruited to phase 1 oncology trials between 2013 and 2017 at Memorial Sloan Kettering Cancer Center. Clinicopathologic data were extracted to characterize DILI, and attribution was assessed on the basis of data prospectively generated during the studies. Logistic regression models were used to explore factors related to DILI and DILI recurrence after drug rechallenge. RESULTS: Among 1670 cases recruited to 85 phase 1 trials, 81 (4.9%) developed DILI. The rate of DILI occurrence was similar for patients in immune-based trials and patients in targeted therapy trials (5.0% vs 4.9%), as was the median time to DILI (5.5 vs 6.5 weeks; P = .48). Two patients (0.12%) met the criteria of Hy's law, although none developed ALF. The DILI resolved in 96% of the patients. Pretreatment factors were not predictive for DILI development. Thirty-six of the 81 patients underwent a drug rechallenge, and 28% of these patients developed DILI recurrence. Peak alanine aminotransferase during the initial DILI was associated with DILI recurrence (odds ratio, 1.04; 95% confidence interval, 1.0-1.09; P = .035). CONCLUSIONS: In modern phase 1 oncology trials, DILI is uncommon, may occur at any time, and often resolves with supportive measures. Rechallenging after DILI is feasible; however, the high rate of DILI recurrence suggests that clinicians should consider the severity of the DILI episode and treatment alternatives.

Overall Survival with Combined Nivolumab and Ipilimumab in Advanced Melanoma.

BACKGROUND: Nivolumab combined with ipilimumab resulted in longer progression-free survival and a higher objective response rate than ipilimumab alone in a phase 3 trial involving patients with advanced melanoma. We now report 3-year overall survival outcomes in this trial. METHODS: We randomly assigned, in a 1:1:1 ratio, patients with previously untreated advanced melanoma to receive nivolumab at a dose of 1 mg per kilogram of body weight plus ipilimumab at a dose of 3 mg per kilogram every 3 weeks for four doses, followed by nivolumab at a dose of 3 mg per kilogram every 2 weeks; nivolumab at a dose of 3 mg per kilogram every 2 weeks plus placebo; or ipilimumab at a dose of 3 mg per kilogram every 3 weeks for four doses plus placebo, until progression, the occurrence of unacceptable toxic effects, or withdrawal of consent. Randomization was stratified according to programmed death ligand 1 (PD-L1) status, BRAF mutation status, and metastasis stage. The two primary end points were progression-free survival and overall survival in the nivolumab-plus-ipilimumab group and in the nivolumab group versus the ipilimumab group. RESULTS: At a minimum follow-up of 36 months, the median overall survival had not been reached in the nivolumab-plus-ipilimumab group and was 37.6 months in the nivolumab group, as compared with 19.9 months in the ipilimumab group (hazard ratio for death with nivolumab plus ipilimumab vs. ipilimumab, 0.55 [P<0.001]; hazard ratio for death with nivolumab vs. ipilimumab, 0.65 [P<0.001]). The overall survival rate at 3 years was 58% in the nivolumab-plus-ipilimumab group and 52% in the nivolumab group, as compared with 34% in the ipilimumab group. The safety profile was unchanged from the initial report. Treatment-related adverse events of grade 3 or 4 occurred in 59% of the patients in the nivolumab-plus-ipilimumab group, in 21% of those in the nivolumab group, and in 28% of those in the ipilimumab group. CONCLUSIONS: Among patients with advanced melanoma, significantly longer overall survival occurred with combination therapy with nivolumab plus ipilimumab or with nivolumab alone than with ipilimumab alone. (Funded by Bristol-Myers Squibb and others; CheckMate 067 ClinicalTrials.gov number, NCT01844505 .).

Survival Outcomes After Metastasectomy in Melanoma Patients Categorized by Response to Checkpoint Blockade.

INTRODUCTION: Checkpoint inhibitors have improved outcomes in metastatic melanoma, with 4-year overall survival (OS) of 46% for anti-PD-1 alone or 53% in combination with anti-CTLA-4. However, the median progression free survival is 6.9 and 11.5 months, respectively. Many who progress have gone on to alternative treatments, including surgery, yet the outcome of patients selected for surgery after checkpoint blockade remains unclear. METHODS: Patients who were treated with checkpoint blockade from 2003 to 2017, followed by metastasectomy, were identified from a prospectively maintained institutional melanoma database. Response to immunotherapy was assessed at the time of surgery. Patients were categorized as having responding, isolated progressing, or multiple progressing lesions. RESULTS: Of the 237 total patients identified, 208 (88%) had stage IV disease, and 29 (12%) had unresectable stage III disease at the start of immunotherapy. Median OS following first resection was 21 months. Median follow-up among survivors was 23 months. Complete resection at the first operation (n = 87, 37%) was associated with improved survival compared with patients with incomplete resection (n = 150, 63%) [median OS not reached (NR) vs. 10.8 months, respectively; 95% CI: 7.3, 14.8; p < 0.0001]. Patients resected for an isolated progressing or responding tumor had a longer median survival compared with those with multiple progressing lesions (NR vs. 7.8 months, 95% CI: 6.2, 11.2; p < 0.0001). CONCLUSIONS: Patients selected for surgical resection following checkpoint blockade have a relatively favorable survival, especially if they had a response to immunotherapy and undergo complete resection of isolated progressing or responding disease.

Myocarditis Surveillance in Patients with Advanced Melanoma on Combination Immune Checkpoint Inhibitor Therapy: The Memorial Sloan Kettering Cancer Center Experience.

This letter to the editor describes myocarditis screening among patients undergoing combination immune checkpoint inhibitor therapy, in light of the consensus document from the Checkpoint Inhibitor Safety Working Group.

Early disease progression and treatment discontinuation in patients with advanced ovarian cancer receiving immune checkpoint blockade.

OBJECTIVE: Delayed responses observed with immune checkpoint blockade (ICB) present a challenge for patients with peritoneal malignancies, who risk early symptomatic disease progression requiring treatment discontinuation. While efforts are ongoing to define the biomarkers of response, it is equally important to identify patients at risk for early discontinuation. We sought to investigate the timing of disease progression in epithelial ovarian cancer (EOC) patients treated with ICB and to identify pre-treatment clinical parameters associated with early discontinuation. METHODS: Retrospective analysis was performed on EOC patients treated with ICB at MSKCC from January 2013 to May 2017. Cutoffs for early and very early discontinuation due to disease progression were defined at 12 and 8 weeks, respectively. Univariate and multivariate logistic regression models were built based on pre-treatment clinical variables. RESULTS: Of 108 identified patients, 89 were included in the analysis. Forty-six (51.7%) patients discontinued therapy early, 30 of which (33.7%) discontinued therapy very early. Eight patients (9.0%) died within 12 weeks of ICB initiation from disease progression. In multivariate analyses, bulky peritoneal disease (p = 0.009, OR: 4.94) and liver parenchymal metastases (p = 0.001, OR: 8.08) were associated with early discontinuation. Liver parenchymal metastases (p = 0.001, OR 6.64), and high neutrophil-to-lymphocyte ratio (p = 0.021, OR: 3.54), were associated with very early discontinuation. CONCLUSIONS: Over 50% of EOC patients suffer disease progression requiring early discontinuation of ICB. Pre-treatment prognostic clinical characteristics may identify patients at highest risk for early discontinuation due to disease progression and warrant caution in using these agents in late line patients with advanced disease.

Combined Nivolumab and Ipilimumab or Monotherapy in Untreated Melanoma.

BACKGROUND: Nivolumab (a programmed death 1 [PD-1] checkpoint inhibitor) and ipilimumab (a cytotoxic T-lymphocyte-associated antigen 4 [CTLA-4] checkpoint inhibitor) have been shown to have complementary activity in metastatic melanoma. In this randomized, double-blind, phase 3 study, nivolumab alone or nivolumab plus ipilimumab was compared with ipilimumab alone in patients with metastatic melanoma. METHODS: We assigned, in a 1:1:1 ratio, 945 previously untreated patients with unresectable stage III or IV melanoma to nivolumab alone, nivolumab plus ipilimumab, or ipilimumab alone. Progression-free survival and overall survival were coprimary end points. Results regarding progression-free survival are presented here. RESULTS: The median progression-free survival was 11.5 months (95% confidence interval [CI], 8.9 to 16.7) with nivolumab plus ipilimumab, as compared with 2.9 months (95% CI, 2.8 to 3.4) with ipilimumab (hazard ratio for death or disease progression, 0.42; 99.5% CI, 0.31 to 0.57; P<0.001), and 6.9 months (95% CI, 4.3 to 9.5) with nivolumab (hazard ratio for the comparison with ipilimumab, 0.57; 99.5% CI, 0.43 to 0.76; P<0.001). In patients with tumors positive for the PD-1 ligand (PD-L1), the median progression-free survival was 14.0 months in the nivolumab-plus-ipilimumab group and in the nivolumab group, but in patients with PD-L1-negative tumors, progression-free survival was longer with the combination therapy than with nivolumab alone (11.2 months [95% CI, 8.0 to not reached] vs. 5.3 months [95% CI, 2.8 to 7.1]). Treatment-related adverse events of grade 3 or 4 occurred in 16.3% of the patients in the nivolumab group, 55.0% of those in the nivolumab-plus-ipilimumab group, and 27.3% of those in the ipilimumab group. CONCLUSIONS: Among previously untreated patients with metastatic melanoma, nivolumab alone or combined with ipilimumab resulted in significantly longer progression-free survival than ipilimumab alone. In patients with PD-L1-negative tumors, the combination of PD-1 and CTLA-4 blockade was more effective than either agent alone. (Funded by Bristol-Myers Squibb; CheckMate 067 ClinicalTrials.gov number, NCT01844505.).

Nivolumab monotherapy in recurrent metastatic urothelial carcinoma (CheckMate 032): a multicentre, open-label, two-stage, multi-arm, phase 1/2 trial.

BACKGROUND: Few effective treatments exist for patients with advanced urothelial carcinoma that has progressed after platinum-based chemotherapy. We assessed the activity and safety of nivolumab in patients with locally advanced or metastatic urothelial carcinoma whose disease progressed after previous platinum-based chemotherapy. METHODS: In this phase 1/2, multicentre, open-label study, we enrolled patients (age ≥18 years) with urothelial carcinoma of the renal pelvis, ureter, bladder, or urethra at 16 sites in Finland, Germany, Spain, the UK, and the USA. Patients were not selected by PD-L1 expression, but tumour PD-L1 membrane expression was assessed retrospectively. Patients received nivolumab 3 mg/kg intravenously every 2 weeks until disease progression or treatment discontinuation because of unacceptable toxicity or other protocol-defined reasons, whichever occurred later. The primary endpoint was objective response by investigator assessment. All patients who received at least one dose of the study drug were included in the analyses. We report an interim analysis of this ongoing trial. CheckMate 032 is registered with ClinicalTrials.gov, NCT01928394. FINDINGS: Between June 5, 2014, and April 24, 2015, 86 patients with metastatic urothelial carcinoma were enrolled in the nivolumab monotherapy group and 78 received at least one dose of treatment. At data cutoff (March 24, 2016), the minimum follow-up was 9 months (median 15·2 months, IQR 12·9-16·8). A confirmed investigator-assessed objective response was achieved in 19 (24·4%, 95% CI 15·3-35·4) of 78 patients. Grade 3-4 treatment-related adverse events occurred in 17 (22%) of 78 patients; the most common were elevated lipase (four [5%]), elevated amylase (three [4%]), and fatigue, maculopapular rash, dyspnoea, decreased lymphocyte count, and decreased neutrophil count (two [3%] each). Serious adverse events were reported in 36 (46%) of 78 patients and eight (10%) had a serious adverse event judged to be treatment related. Two (3%) of 78 patients discontinued because of treatment-related adverse events (grade 4 pneumonitis and grade 4 thrombocytopenia) and subsequently died. INTERPRETATION: Nivolumab monotherapy was associated with a substantial and durable clinical response and a manageable safety profile in previously treated patients with locally advanced or metastatic urothelial carcinoma. These data support further investigation of nivolumab monotherapy in advanced urothelial carcinoma. FUNDING: Bristol-Myers Squibb.

Immune modulation in cancer with antibodies.

Ipilimumab is the prototypical immunomodulatory antibody, approved by the FDA in 2011 for advanced melanoma on the basis of survival benefit. Since that time, we have made significant strides in optimizing this therapy: we have characterized the spectrum of immune-related adverse events and learned how to mitigate them with treatment algorithms, discovered potential biomarkers of activity, and identified the potential synergy between checkpoint modulation and other therapeutic modalities. Recent phase I trials have established the efficacy and safety of next-generation checkpoint agents, including PD-1 and PD-L1 inhibitors, across multiple tumor types. Much work lies ahead in developing these next-generation checkpoint agents, testing them in combination, and determining how to integrate them into the treatment paradigms of various tumor types.

Prognosis of Mucosal, Uveal, Acral, Nonacral Cutaneous, and Unknown Primary Melanoma From the Time of First Metastasis.

BACKGROUND: Subtypes of melanoma, such as mucosal, uveal, and acral, are believed to result in worse prognoses than nonacral cutaneous melanoma. After a diagnosis of distant metastatic disease, however, the overall survival of patients with mucosal, uveal, acral, nonacral cutaneous, and unknown primary melanoma has not been directly compared. MATERIALS AND METHODS: We conducted a single-center, retrospective analysis of 3,454 patients with melanoma diagnosed with distant metastases from 2000 to 2013, identified from a prospectively maintained database. We examined melanoma subtype, date of diagnosis of distant metastases, age at diagnosis of metastasis, gender, and site of melanoma metastases. RESULTS: Of the 3,454 patients (237 with mucosal, 286 with uveal, 2,292 with nonacral cutaneous, 105 with acral cutaneous, and 534 with unknown primary melanoma), 2,594 died. The median follow-up was 46.1 months. The median overall survival for those with mucosal, uveal, acral, nonacral cutaneous, and unknown primary melanoma was 9.1, 13.4, 11.4, 11.7, and 10.4 months, respectively. Patients with uveal melanoma, cutaneous melanoma (acral and nonacral), and unknown primary melanoma had similar survival, but patients with mucosal melanoma had worse survival. Patients diagnosed with metastatic melanoma in 2006-2010 and 2011-2013 had better overall survival than patients diagnosed in 2000-2005. In a multivariate model, patients with mucosal melanoma had inferior overall survival compared with patients with the other four subtypes. CONCLUSION: Additional research and advocacy are needed for patients with mucosal melanoma because of their shorter overall survival in the metastatic setting. Despite distinct tumor biology, the survival was similar for those with metastatic uveal melanoma, acral, nonacral cutaneous, and unknown primary melanoma. IMPLICATIONS FOR PRACTICE: Uveal, acral, and mucosal melanoma are assumed to result in a worse prognosis than nonacral cutaneous melanoma or unknown primary melanoma. No studies, however, have been conducted assessing the overall survival of patients with these melanoma subtypes starting at the time of distant metastatic disease. The present study found that patients with uveal, acral, nonacral cutaneous, and unknown primary melanoma have similar overall survival after distant metastases have been diagnosed. These findings provide information for oncologists to reconsider previously held assumptions and appropriately counsel patients. Patients with mucosal melanoma have worse overall survival and are thus a group in need of specific research and advocacy.

Nivolumab plus ipilimumab in advanced melanoma.

BACKGROUND: In patients with melanoma, ipilimumab (an antibody against cytotoxic T-lymphocyte-associated antigen 4 [CTLA-4]) prolongs overall survival, and nivolumab (an antibody against the programmed death 1 [PD-1] receptor) produced durable tumor regression in a phase 1 trial. On the basis of their distinct immunologic mechanisms of action and supportive preclinical data, we conducted a phase 1 trial of nivolumab combined with ipilimumab in patients with advanced melanoma. METHODS: We administered intravenous doses of nivolumab and ipilimumab in patients every 3 weeks for 4 doses, followed by nivolumab alone every 3 weeks for 4 doses (concurrent regimen). The combined treatment was subsequently administered every 12 weeks for up to 8 doses. In a sequenced regimen, patients previously treated with ipilimumab received nivolumab every 2 weeks for up to 48 doses. RESULTS: A total of 53 patients received concurrent therapy with nivolumab and ipilimumab, and 33 received sequenced treatment. The objective-response rate (according to modified World Health Organization criteria) for all patients in the concurrent-regimen group was 40%. Evidence of clinical activity (conventional, unconfirmed, or immune-related response or stable disease for ≥24 weeks) was observed in 65% of patients. At the maximum doses that were associated with an acceptable level of adverse events (nivolumab at a dose of 1 mg per kilogram of body weight and ipilimumab at a dose of 3 mg per kilogram), 53% of patients had an objective response, all with tumor reduction of 80% or more. Grade 3 or 4 adverse events related to therapy occurred in 53% of patients in the concurrent-regimen group but were qualitatively similar to previous experience with monotherapy and were generally reversible. Among patients in the sequenced-regimen group, 18% had grade 3 or 4 adverse events related to therapy and the objective-response rate was 20%. CONCLUSIONS: Concurrent therapy with nivolumab and ipilimumab had a manageable safety profile and provided clinical activity that appears to be distinct from that in published data on monotherapy, with rapid and deep tumor regression in a substantial proportion of patients. (Funded by Bristol-Myers Squibb and Ono Pharmaceutical; ClinicalTrials.gov number, NCT01024231.).

Checkpoint Blockade for the Treatment of Advanced Melanoma.

Immunotherapy with immune checkpoint inhibition has been improving the outcomes of patients with many different types of malignancies. Immune checkpoint inhibition has been most extensively studied in patients with advanced melanoma and there are three FDA approved antibodies already widely used in clinical practice (ipilimumab, nivolumab, and pembrolizumab). In this chapter, we review the mechanistic basis behind the development of immune checkpoint blocking antibodies. We then discuss specifics regarding each agent, unique clinical considerations in treating patients with this approach, and future directions, including combination strategies. This chapter is focused on melanoma, but the principles related to this immunotherapy approach are applicable to patients with many types of malignancies.

Progression of RAS-mutant leukemia during RAF inhibitor treatment.

Vemurafenib, a selective RAF inhibitor, extends survival among patients with BRAF V600E-mutant melanoma. Vemurafenib inhibits ERK signaling in BRAF V600E-mutant cells but activates ERK signaling in BRAF wild-type cells. This paradoxical activation of ERK signaling is the mechanistic basis for the development of RAS-mutant squamous-cell skin cancers in patients treated with RAF inhibitors. We report the accelerated growth of a previously unsuspected RAS-mutant leukemia in a patient with melanoma who was receiving vemurafenib. Exposure to vemurafenib induced hyperactivation of ERK signaling and proliferation of the leukemic cell population, an effect that was reversed on drug withdrawal.

Immunologic correlates of the abscopal effect in a patient with melanoma.

The abscopal effect is a phenomenon in which local radiotherapy is associated with the regression of metastatic cancer at a distance from the irradiated site. The abscopal effect may be mediated by activation of the immune system. Ipilimumab is a monoclonal antibody that inhibits an immunologic checkpoint on T cells, cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4). We report a case of the abscopal effect in a patient with melanoma treated with ipilimumab and radiotherapy. Temporal associations were noted: tumor shrinkage with antibody responses to the cancer-testis antigen NY-ESO-1, changes in peripheral-blood immune cells, and increases in antibody responses to other antigens after radiotherapy. (Funded by the National Institutes of Health and others.).

Decoding Spatial Tissue Architecture: A Scalable Bayesian Topic Model for Multiplexed Imaging Analysis.

Recent progress in multiplexed tissue imaging is advancing the study of tumor microenvironments to enhance our understanding of treatment response and disease progression. Cellular neighborhood analysis is a popular computational approach for these complex image data. Despite its popularity, there are significant challenges, including high computational demands that limit feasibility for large-scale applications and the lack of a principled strategy for integrative analysis across images. This absence hampers the precise and consistent identification of spatial features and tracking of their dynamics over disease progression. To overcome these challenges, we introduce SpaTopic, a spatial topic model designed to decode high-level spatial architecture across multiplexed tissue images. This algorithm integrates both cell type and spatial information within a topic modelling framework, originally developed for natural language processing and adapted for computer vision. Spatial information is incorporated into the flexible design of documents, representing densely overlapping regions in images. The model employs an efficient collapsed Gibbs sampling algorithm for both statistical and computational inference. We benchmarked the performance against five state-of-the-art algorithms through various case studies using different single-cell spatial transcriptomic and proteomic imaging platforms across different tissue types. Our findings demonstrate that SpaTopic consistently identifies biologically and clinically significant spatial "topics" such as tertiary lymphoid structures (TLSs) and tracks dynamic changes in spatial features over disease progression. Its computational efficiency and broad applicability across various molecular imaging platforms will enhance the analysis of large-scale tissue imaging datasets.

Durable complete response in a patient with leptomeningeal melanoma after treatment with dabrafenib, trametinib, and nivolumab.

Leptomeningeal disease (LMD) is a devastating complication of melanoma with a dismal prognosis. We present the case of a young man with stage IV BRAF V600E mutant melanoma with lung, lymph node, and brain metastases initially treated with ipilimumab and nivolumab, who subsequently developed LMD. Upon change to BRAF/MEK targeted therapy with nivolumab, a durable complete response was achieved and remains ongoing, off treatment, 7 years from diagnosis. Management of symptomatic LMD remains a critical unmet clinical challenge, with limited clinical trial data. This exceptional case is instructive, as the first published case of the use of the triplet, and the first durable response with therapy discontinuation, in melanoma LMD. The triple-drug regimen may be considered a viable option in fit patients. This case highlights the potential for long-term disease control and the critical and urgent need to develop clinical trials inclusive of patients with LMD to define the best treatment strategies.