Flotte, Thomas J.

9503 Background: Neoadjuvant ± adjuvant immunotherapy improves event-free survival relative to adjuvant immunotherapy alone for patients with high-risk resectable stage III melanoma. However, the optimal regimen balancing efficacy and tolerability is not known. T-cell immunoglobulin and ITIM domain (TIGIT) is a promising immune checkpoint but its therapeutic potential in stage III melanoma is underexplored. Methods: In this phase II trial, patients with resectable, macroscopic stage III melanoma received four 21-day neoadjuvant cycles of 1200mg IV atezolizumab (atezo, anti-PD-L1) + 600mg IV tiragolumab (tira, anti-TIGIT), followed by therapeutic lymph node dissection (TLND) and eight 21-day adjuvant cycles of 1200mg IV atezo. Primary endpoints were pathologic response (of all patients initiating neoadjuvant therapy) and recurrence-free survival (RFS) from the time of TLND in patients who were operated on per protocol and received adjuvant therapy. Secondary endpoint was adverse events (AEs); exploratory endpoints included event-free survival (EFS) and distant metastasis-free survival (DMFS). Results: Thirty-four patients, median age 59 years, were accrued and initiated neoadjuvant atezo/tira. 76.5% had >1 metastatic lymph node involved at baseline and 73.5% presented with Stage IIIC disease. All 34 patients were evaluable for AEs, pathologic response and EFS. Four patients were diagnosed with metastatic disease during neoadjuvant treatment, while 30 had TLND per protocol and 28 received adjuvant treatment and were evaluable for RFS and DMFS. Major pathologic responses (MPR, ≤10% viable tumor) were observed in 16/34 patients (47.1%, Table). With 19.9 months median follow-up from registration, 12-month EFS was 72.0% (95% CI 57.9 to 89.5%). With 16 months median follow-up from operation, 12-month RFS was 73.3% (n=28, 95% CI 56.9 to 94.5%), while 12-month DMFS was 86.0% (n=28, 95% CI 72.2 to 100%). In the 16 patients with an MPR, 2 did not receive adjuvant treatment and were followed for 33.3 and 10.8 months without recurrence/death. In the remaining 14 patients, 12-month RFS and 12-month DMFS were both 91.7% (95% CI 77.3 to 100%). 5 patients (14.7%) experienced any grade 3+ AE with 2 (5.9%) at least possibly related to the neoadjuvant regimen. Conclusions: Among patients with high-risk resectable stage III melanoma, neoadjuvant atezo/tira was a promising regimen with a favorable safety profile and warrants further study. Identification of predictive biomarkers will allow for optimization of neoadjuvant therapy for individual patients. Clinical trial information: NCT03554083 . Pathologic response. N=34 Major Pathologic Response 16 (47.1%) Pathologic complete response (no viable tumor) 13 (38.2%) Near-pathologic complete response (0.1−10% viable tumor) 3 (8.8%) Pathologic partial response (>10.0−50% viable tumor) 2 (5.9%) Pathologic non-response (>50% viable tumor) 12 (35.3%) No per protocol operation 4 (11.8%)

Background Neoadjuvant treatment has become standard for patients with high-risk operable stage III melanoma, but the optimal regimen is unknown. Targeted therapy approaches yield high pathological response rates, while immunotherapy regimens show favorable recurrence-free survival (RFS). NeoACTIVATE was designed to address whether a neoadjuvant combination of both targeted therapy and immunotherapy might leverage the benefits of each. Methods We tested neoadjuvant treatment with 12 weeks of vemurafenib, cobimetinib, and atezolizumab for patients with BRAF-mutated (BRAFm) melanoma (cohort A) and cobimetinib and atezolizumab for patients with BRAF-wild-type (BRAFwt) melanoma (cohort B), regimens which we have shown generate a substantial major pathological response. After therapeutic lymph node dissection, patients received 24 weeks of adjuvant atezolizumab. Here, we report survival outcomes and their association with biomarkers assayed among the gut microbiome and peripheral blood immune subsets. Results With 49 months median follow-up, the median RFS was not reached for cohort A and was 40.8 months for cohort B. At 24 months after operation, 2 of 14 cohort A patients and 4 of 13 cohort B patients had experienced distant relapse. Key findings from correlative analyses included diversity, taxonomic and functional metagenomic gut microbiome signals associated with distant metastasis-free survival at 2 years. Notably, we observed a strong correlation between low microbial arginine biosynthesis (required for T-cell activation and effector function) and early distant recurrence (p=0.0005), which correlated with taxonomic differential abundance findings. Peripheral blood immune monitoring revealed increased double-positive (CD4+CD8+) T cells in patients with early recurrence. Conclusions Neoadjuvant treatment with cobimetinib and atezolizumab±vemurafenib was associated with a low rate of distant metastasis in patients with high-risk stage III melanoma. Freedom from early distant metastasis was highly associated with taxonomic differences in gut microbiome structure and with functional pathway alterations known to modulate T cell immunity. Identification of predictive biomarkers will permit optimization of neoadjuvant therapy regimens for individual patients. Trial registration number NCT03554083.

Context.— Artificial intelligence is a transforming technology for anatomic pathology. Involvement within the workforce will foster support for algorithm development and implementation. Objective.— To develop a supportive ecosystem that enables pathologists with variable expertise in artificial intelligence to create algorithms in a development environment with seamless transition to a production environment. Design.— Platform requirements included (1) approachable and intuitive user interface, (2) diverse algorithmic modeling options, (3) support capability for internal and external collaborations, (4) a seamless mechanism for discovery to clinical deployment transition, (5) the ability to meet minimum institutional requirements for information technology (IT) review, and (6) the ability to be scalable over time. The ecosystem required platform education, data science guidance, project management structure, and ongoing leadership. Results.— The development team considered internal development and vended solutions. Because of the extended timeline and resource requirements for internal development, a decision was made to use a vended solution. Vendor proposals were solicited and reviewed by pathologists, IT, and security groups. A vendor was selected and pipelines for development and production were established. Proposals for development were solicited from the pathology department. Eighty-four investigators were selected for the initial cohort, receiving training and access to dedicated subject matter experts. A total of 30 of 31 projects progressed through the model development process of annotating, training, and validation. Based on these projects, 15 abstracts were submitted to national meetings. Conclusions.— Democratizing artificial intelligence by creating an ecosystem to support pathologists with varying levels of expertise can break down entry barriers, reduce overall cost of algorithm development, improve algorithm quality, and enhance the speed of adoption.

Abstract BACKGROUND: Effective approaches for prevention of hepatocellular carcinoma (HCC) will have a significant impact on HCC-related mortality. Data from preclinical models strongly support epidermal growth factor receptor (EGFR) as a target for chemoprevention of HCC. Erlotinib is a small-molecular EGFR tyrosine kinase inhibitor that is FDA-approved for cancer treatment. The side effects of erlotinib observed in patients receiving the oncology dose (150 mg/day) render it unacceptable as a chemoprevention agent at this dose. OBJECTIVE: The objective of this clinical trial was determination of a safe and minimum effective dose of erlortinib for which a ≥50% reduction phospho-EGFR immunohistochemical staining in the liver was observed. RESULTS: 46 participants were pre-registered and 25 participants were registered in this multicenter trial. In a dose de-escalation trial design, cohorts of participants received a 7 day course of erlotinib 75 mg/day, 50 mg/day or 25 mg/day with liver tissue acquisition prior to and after erlotinib. A ≥50% reduction phospho-EGFR immunohistochemical staining in the liver was observed in a minimum of 40% of participants at each of the dose levels. Erlotinib was very well tolerated with few side effects observed, particularly at the dose of 25 mg/day. A favorable modulation of the Prognostic Liver Signature was observed in participants that received the higher erlotinib doses (50 and 75 mg/day). CONCLUSION: These data support the selection a dose of 25 mg/day of erlotinib for a longer intervention to assess for evidence of efficacy as an HCC chemoprevention drug. Citation Format: Kenneth K. Tanabe, David Zahrieh, Carrie A. Strand, Yujin Hoshida, Thomas J. Flotte, Gary Della’Zanna, Asad Umar, Paul Limburg. Pilot study of EGFR inhibition with erlotinib in liver fibrosis for hepatocellular carcinoma prevention [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3031.

Abstract Objectives To learn what color vision–deficient pathologists and cytotechnologists consider their most significant problems and advantages as well as any accommodations. Methods An anonymous online survey developed for practicing pathologists and cytotechnologists regarding their experiences with stains was sent to the members of 4 national societies. Results We received 377 responses. Twenty-three people, all men, identified themselves as color vision deficient, with 22 reporting red-green color vision deficiency and 1 reporting uncertain type. Eight pathologists and cytotechnologists indicated that they thought that their color vision deficiency conferred advantages to them, including a greater appreciation of morphology, with less confusion resulting from variations in stain quality or intensity. Nineteen pathologists and cytotechnologists thought that their color vision deficiency conferred disadvantages; the most common disadvantages stated were the identification of eosinophils and acid-fast bacilli. Other difficulties included interpretation of RBCs and nucleoli and sometimes Alcian blue, Brown and Brenn, Congo red, crystal violet, Fite, Giemsa, mucicarmine, periodic acid–Schiff, and fluorescence in situ hybridization stains. Only 2 of the color vision–deficient pathologists and cytotechnologists found digital slides more difficult than glass slides. Conclusions Color vision–deficient pathologists and cytotechnologists report that they have developed approaches to viewing slides that do not compromise their interpretations. Digital pathology may provide several approaches for aiding color vision–deficient pathologists with the interpretation of certain stains.

Direct interactions between tumor and immune cells mediate the antitumor effect of all modern cancer immunotherapeutic agents. Simultaneously, tumor cells have evolved mechanisms of evasion, including the downregulation of HLA-I, potentially disrupting the mechanism of action employed by many immune checkpoint inhibitors. And yet, the in situ interplay between these cells within the tumor immune microenvironment (TIME) remains elusive. Recent advances in histologic multiplex bioimaging platforms have enabled in-depth molecular characterization of single cells within spatially preserved and clinically archived tumor tissues. Herein, we applied multiplex immunofluorescence to excisional lymph node biopsies from 14 patients with metastatic melanoma who experienced clear objective responses to immunotherapy (7 complete response; 7 progressive disease) to determine distinguishing features of the TIME in the pretreatment setting. Distinct regions of the TIME were evaluated using 35 proteins probing tumor, immune, and vasculature components across 323 fields of view. Single-cell compositional analysis confirmed established prognostic immune cell types including increased prevalence of cytotoxic T cells within the tumor core fields of view of responders. Integrating single-cell quantification with the spatial arrangement of cellular neighborhoods surrounding tumor cells revealed novel, spatial immune signatures capable of stratifying TIME based on clinical response. Our analysis revealed dynamic cellular composition of the tumor-centric cellular neighborhood (TCCN) based on anatomic subregion, functional expression of HLA-I by the index tumor cell and ultimately clinical response to immunotherapy. Overall, this study provides an analytic framework to resolve the cellular complexity of the TIME, increasingly relevant to the outcomes of modern cancer immunotherapy. Significance: Findings from this work propose a novel approach to resolving clinical heterogeneity of the TIME by objectively quantifying the cellular interactions occurring in metastatic melanoma lymph node tissue utilizing multiplex immunofluorescence. This study provides an analytic and biologically derived unit of measure, the TCCN which is customizable for studying critical paracrine interactions within spatially preserved tissue of various cancers and across the spectrum of multiplex imaging modalities.

AbstractBackgroundBenign capsular nevi (BCN) are not infrequent in sentinel lymph nodes (SLN) of patients with melanoma. Their prognostic significance is unknown and the literature is limited. This study evaluated the clinical significance of incidentally found BCN in these patients.MethodsA multi‐institutional retrospective review of patients undergoing SLN biopsy for cutaneous melanoma between 2000 and 2016. Patients were divided into the following groups: (a) negative SLN and no BCN, (b) negative SLN and presence of BCN, (c) positive SLN seen only on immunohistochemistry (IHC), and (d) positive SLN via hematoxylin and eosin (H&E). Outcomes measured were overall survival and any recurrence.ResultsA total of 1253 patients were identified (group 1 = 978, group 2 = 56, group 3 = 32, and group 4 = 187). Fifty‐seven percent were male and the mean age was 59.3 years. BCN was identified in 77 patients (6.2%), of which the majority was in the node‐negative group (72%). Multivariable analysis showed that BCN was associated with lower recurrence rates, though not statistically significant (hazard ratio [HR] = 0.5; P = .06). IHC‐ and H&E‐positive SLNs were associated with a higher risk of recurrence (HR = 2.4; P = .02 and 2.0, P < .0001, respectively).ConclusionPatients with BCN and negative SLN had lower recurrence rates than patients with negative SLN and no BCN. Our data suggest a possible protective effect against recurrence.

AimsRecently, a novel isoform of anaplastic lymphoma kinase, with alternative transcription initiation (ALKATI), has been described in melanoma and is susceptible to targeted ALK‐inhibitor therapy. Clinical outcomes of patients with ALKATI mutated melanoma as well as correlation with immunohistochemical (IHC) methods have not yet been described.Methods and resultsClinicopathological characteristics were abstracted for 324 patients with metastatic melanoma (MM). IHC, fluorescence in‐situ hybridisation and RNA‐based digital molecular analysis assays were performed on archival tissue from 173 stage III and 192 stage IV tumours. ALKATI was identified in 12.7 and 4.8% stage III and IV tumours, respectively. Discrete presentations of the ALKATI are seen: isolated ALKATI (n = 20) and mixed ALKATI (combined ALKATI and ALKWT; n = 7). Isolated ALKWT expression (n = 4) was seen with no ALK fusions. Stage III patients showed improved survival with ALKATI expression compared to those with ALKWT or no expression [5‐year survival 80, 95% confidence interval (CI) = 57–100% versus 43%, 95% CI = 34–55%, P = 0.013]. Clinicopathological characteristics were not statistically significant. Strong diffuse cytoplasmic staining of ALK IHC (n = 12) has a sensitivity of 52.2%, specificity 100%, PPV of 100% and NPV of 92.5% of detecting isolated ALKATI.ConclusionPresence of ALKATI is a good prognostic indicator in MM. ALK IHC and digital molecular analysis can be incorporated into MM evaluation to identify patients with ALKATI for targeted therapy.