Assay Validation of Cell-Free DNA Shallow Whole-Genome Sequencing to Determine Tumor Fraction in Advanced Cancers

Blood-based liquid biopsy is increasingly used in clinical care of patients with cancer, and fraction of tumor-derived DNA in circulation (tumor fraction; TFx) has demonstrated clinical validity across multiple cancer types. To determine TFx, shallow whole-genome sequencing of cell-free DNA (cfDNA) can be performed from a single blood sample, using an established computational pipeline (ichorCNA), without prior knowledge of tumor mutations, in a highly cost-effective manner. We describe assay validation of this approach to facilitate broad clinical application, including evaluation of assay sensitivity, precision, repeatability, reproducibility, pre-analytic factors, and DNA quality/quantity. Sensitivity to detect TFx of 3% (lower limit of detection) was 97.2% to 100% at 1× and 0.1× mean sequencing depth, respectively. Precision was demonstrated on distinct sequencing instruments (HiSeqX and NovaSeq) with no observable differences. The assay achieved prespecified 95% agreement of TFx across replicates of the same specimen (repeatability) and duplicate samples in different batches (reproducibility). Comparison of samples collected in EDTA and Streck tubes from single venipuncture in 23 patients demonstrated that EDTA or Streck tubes were comparable if processed within 8 hours. On the basis of a range of DNA inputs (1 to 50 ng), 20 ng cfDNA is the preferred input, with 5 ng minimum acceptable. Overall, this shallow whole-genome sequencing of cfDNA and ichorCNA approach offers sensitive, precise, and reproducible quantitation of TFx, facilitating assay application in clinical cancer care.

A Single Arm Phase 2 Trial of Trametinib in Patients With Locally Advanced or Metastatic Epithelioid Hemangioendothelioma

PURPOSE

Epithelioid hemangioendothelioma (EHE) is a rare vascular cancer with pathogenic TAZ-CAMTA1 operating as an oncogenic driver through activation of MAPK pathway. Trametinib is an inhibitor of MEK, a critical kinase in the MAPK pathway. We sought to evaluate the effect of trametinib in patients with EHE.

PATIENTS AND METHODS

A phase 2 trial of trametinib was conducted in patients with locally advanced or metastatic EHE. Eligibility requirements included evidence of tumor progression or presence of EHE-related pain requiring opiates for management prior to enrollment. The primary endpoint was objective response rate (ORR) per RECIST1.1 in cases with TAZ-CAMTA1 confirmed by fusion-FISH. Secondary objectives were to estimate ORR for all patients, median PFS, 2-year OS rate, patient safety, and change in patient-reported global health and pain scores per PROMIS questionnaires.

RESULTS

44 patients enrolled and 42 started trametinib. TAZ-CAMTA1 was detected in 27 tumor samples. The ORR was 3.7% (95% CI: 0.094, 19.0), median PFS was 10.4 months (95% CI: 7.1, NA), and 2-year OS rate was 33.3% (95% CI: 19.1, 58.2) in the target population. Median pain intensity and interference scores improved significantly after 4 weeks of trametinib in patients using opiates. Common AEs related to trametinib were rash, fatigue, nausea/vomiting, diarrhea/constipation, alopecia and edema; one Grade 5 ARDS/pneumonitis was related to trametinib.

CONCLUSIONS

Trametinib was associated with reduction in EHE-related pain and median PFS of more than 6 months providing palliative benefit in patients with advanced EHE, but the trial did not meet the ORR goal.

Real-world drug utilization and treatment patterns in patients with tenosynovial giant cell tumors in the USA

Aim: Real-world treatment patterns in tenosynovial giant cell tumor (TGCT) patients remain unknown. Pexidartinib is the only US FDA-approved treatment for TGCT associated with severe morbidity or functional limitations and not amenable to improvement with surgery. Objective: To characterize drug utilization and treatment patterns in TGCT patients. Methods: In a retrospective observational study using IQVIA's linked prescription and medical claims databases (2018-2021), TGCT patients were stratified by their earliest systemic therapy claim (pexidartinib [N = 82] or non-FDA-approved systemic therapy [N = 263]). Results: TGCT patients treated with pexidartinib versus non-FDA-approved systemic therapies were predominantly female (61 vs 50.6%) and their median age was 47 and 54 years, respectively. Pexidartinib-treated patients had the highest 12-month probability of remaining on treatment (54%); 34.1% of pexidartinib users had dose reduction after their first claim. Conclusion: This study provides new insights into the unmet need, utilization and treatment patterns of systemic therapies for the treatment of TGCT patients.

Scalp Irradiation with 3D-Milled Bolus: Initial Dosimetric and Clinical Experience

BACKGROUND AND PURPOSE

A bolus is required when treating scalp lesions with photon radiation therapy. Traditional bolus materials face several issues, including air gaps and setup difficulty due to irregular, convex scalp geometry. A 3D-milled bolus is custom-formed to match individual patient anatomy, allowing improved dose coverage and homogeneity. Here, we describe the creation process of a 3D-milled bolus and report the outcomes for patients with scalp malignancies treated with Volumetric Modulated Arc Therapy (VMAT) utilizing a 3D-milled bolus.

MATERIALS AND METHODS

Twenty-two patients treated from 2016 to 2022 using a 3D-milled bolus and VMAT were included. Histologies included squamous cell carcinoma (n = 14, 64%) and angiosarcoma (n = 8, 36%). A total of 7 (32%) patients were treated in the intact and 15 (68%) in the postoperative setting. The median prescription dose was 66.0 Gy (range: 60.0-69.96).

RESULTS

The target included the entire scalp for 8 (36%) patients; in the remaining 14 (64%), the median ratio of planning target volume to scalp volume was 35% (range: 25-90%). The median dose homogeneity index was 1.07 (range: 1.03-1.15). Six (27%) patients experienced acute grade 3 dermatitis and one (5%) patient experienced late grade 3 skin ulceration. With a median follow-up of 21.4 months (range: 4.0-75.4), the 18-month rates of locoregional control and overall survival were 75% and 79%, respectively.

CONCLUSIONS

To our knowledge, this is the first study to report the clinical outcomes for patients with scalp malignancies treated with the combination of VMAT and a 3D-milled bolus. This technique resulted in favorable clinical outcomes and an acceptable toxicity profile in comparison with historic controls and warrants further investigation in a larger prospective study.

A Bioinformatics Tool for Identifying Intratumoral Microbes from the ORIEN Dataset

Evidence supports significant interactions among microbes, immune cells, and tumor cells in at least 10%-20% of human cancers, emphasizing the importance of further investigating these complex relationships. However, the implications and significance of tumor-related microbes remain largely unknown. Studies have demonstrated the critical roles of host microbes in cancer prevention and treatment responses. Understanding interactions between host microbes and cancer can drive cancer diagnosis and microbial therapeutics (bugs as drugs). Computational identification of cancer-specific microbes and their associations is still challenging due to the high dimensionality and high sparsity of intratumoral microbiome data, which requires large datasets containing sufficient event observations to identify relationships, and the interactions within microbial communities, the heterogeneity in microbial composition, and other confounding effects that can lead to spurious associations. To solve these issues, we present a bioinformatics tool, microbial graph attention (MEGA), to identify the microbes most strongly associated with 12 cancer types. We demonstrate its utility on a dataset from a consortium of nine cancer centers in the Oncology Research Information Exchange Network. This package has three unique features: species-sample relations are represented in a heterogeneous graph and learned by a graph attention network; it incorporates metabolic and phylogenetic information to reflect intricate relationships within microbial communities; and it provides multiple functionalities for association interpretations and visualizations. We analyzed 2,704 tumor RNA sequencing samples and MEGA interpreted the tissue-resident microbial signatures of each of 12 cancer types. MEGA can effectively identify cancer-associated microbial signatures and refine their interactions with tumors.

SIGNIFICANCE

Studying the tumor microbiome in high-throughput sequencing data is challenging because of the extremely sparse data matrices, heterogeneity, and high likelihood of contamination. We present a new deep learning tool, MEGA, to refine the organisms that interact with tumors.

Adjuvant Palbociclib May be Associated with Delayed Recurrence in Completely Resected Retroperitoneal Liposarcoma: Results of a Single-Institution Retrospective Cohort Study

BACKGROUND

Retroperitoneal liposarcomas are locally aggressive and frequently recur following complete surgical resection. Palbociclib, a cyclin-dependent kinase (CDK) 4/CDK6 inhibitor, is effective in the treatment of metastatic or unresectable liposarcoma.

OBJECTIVE

The purpose of this study was to describe our initial experience using adjuvant palbociclib to delay recurrence.

METHODS

Patients with resected RPS were identified from a prospectively maintained institutional database. In 2017, we began offering adjuvant palbociclib to patients following complete gross resection. Treatment interval, defined as the time between surgical resection and re-resection or change in systemic therapy, was compared between patients selected for adjuvant palbociclib or observation.

RESULTS

Between 2017 and 2020, 12 patients underwent a total of 14 operations (14 patient cases) and were selected for adjuvant palbociclib for recurrence prevention. These patients were compared with 14 patients who, since 2010, underwent a total of 20 operations (20 patient cases) and were selected for observation. Histology was primarily dedifferentiated liposarcoma for both groups (observation: 70% [14/20]; adjuvant palbociclib: 64% [9/14]). All patients underwent complete gross resection. Neither age, number of previous surgeries, histologic grade, or Eastern Cooperative Oncology Group (ECOG) performance status differed between groups (p > 0.05 for all). Patients selected for adjuvant palbociclib experienced a longer treatment interval than those selected for observation, although it did not reach statistical significance (20.5 months vs. 13.1 months, p = 0.08, log rank).

CONCLUSION

Adjuvant palbociclib may be associated with a prolonged interval between liposarcoma resection and the need for re-resection or other systemic therapy. Palbociclib may be effective in delaying liposarcoma recurrence, and its use for this indication warrants prospective study.

Clinical Characteristics, Patterns of Care, and Treatment Outcomes of Radiation-Associated Sarcomas

PURPOSE/OBJECTIVE(S)

In this study, we describe the clinical presentation, patterns of care, and treatment outcomes for radiation-associated sarcomas (RAS) patients seen at our institution.

MATERIALS/METHODS

Patients with RAS treated at The Ohio State University Comprehensive Cancer Center between January 1, 2015 and January 20, 2021 were included. Demographic and clinical variables, as well as outcomes, were abstracted from chart review. Differences in outcomes were assessed based on log-rank test.

RESULTS

A total of 38 patients with a diagnosis of RAS were identified (17 males, 21 females). The median age at radiotherapy for index malignancy was 55.3 years (range 0.2-77.5). The median latency following index radiotherapy until the RAS diagnosis was 9.1 years (range 3.7-46.3). The median age at RAS diagnosis was 68.4 years (range 27.9-85.4). The most common index malignancy associated with a subsequent RAS was breast carcinoma (n = 9 [23.7%]). The most common RAS histology was angiosarcoma (n = 10 [26.3%]). Median RAS tumor size was 5.25 cm (range 0.4-30.5). RAS grade was most commonly grade 3 (n = 25 [65.8%]). RAS locations included abdominopelvic (n = 15 [39.5%]); head & neck (n = 10 [26.3%]); and thorax (n = 10 [26.3%]). Genomic profiling identified mutations in TP53 (n = 12 [31.6%]); MYC (n = 6 [15.8%]); and CDK2A/4 (n = 5 [13.2%]). Median tumor mutation burden (TMB) was 2.6 mutations/megabase (range 0.5-6.3). Among the 33 patients with non-metastatic RAS at presentation, 78.8% (n = 26) underwent oncologic resection. Margins were R0 in 69.2% (n = 18), R1 in 19.2% (n = 5), and R2 in 11.5% (n = 3). 54.5% (n = 18) received systemic therapy and 24.2% (n = 8) received radiotherapy as part of curative-intent treatment (median dose 50.4 Gy [range 45-57.5]). For the entire cohort, median PFS was 9.0 months and median OS was 11.1 months. Among patients who presented with non-metastatic RAS, the median LRFS was 9.5 months (range 2.0-34.7); median PFS was 9.0 months (range 2.0-34.7); and median OS was 10.6 months (range 0.6-31.6). Amongst patients with metastatic RAS at presentation, median PFS was 7.4 months (range 1.4-15.8) and median OS was 13.1 months (range 6.0-14.9). Patients who presented with non-metastatic vs metastatic RAS had a significantly longer PFS (p = 0.025) and OS (p = 0.033). Amongst non-metastatic RAS, an R0 resection was associated with significantly improved mean OS (75.3 months [95% CI 54.9-95.8]) in comparison to R1 (15.2 months [95% CI 5.3-25.1]) and R2 margins (19.7 months [95% CI 10.7-28.7]), p = 0.016. Among patients managed with curative intent, there was no significant association between receipt of either systemic therapy or radiotherapy and duration of LC, PFS, or OS.

CONCLUSION

Outcomes for RAS are strikingly poor. Patients with non-metastatic RAS had a significantly longer PFS and OS compared to patients who presented with metastatic RAS. As part of a curative-intent treatment, R0 surgical margins, but not receipt of systemic therapy or radiotherapy, were associated with improved OS in our cohort.

Mean platelet volume, thrombocytosis, and survival in non-small cell lung cancer patients treated with first-line pembrolizumab alone or with chemotherapy

INTRODUCTION

Patients treated with immune checkpoint inhibitors (ICIs) may not response to treatment and are at risk for immune-related adverse events (irAEs). Platelet function has been linked to both oncogenesis and immune evasion. We studied the association between the change in mean platelet volume (MPV), platelet count, survival, and the risk of developing irAEs in patients with metastatic non-small cell lung cancer (NSCLC) who have received first-line ICI.

METHODS

In this retrospective study, delta (∆) MPV was defined as the difference between cycle 2 and baseline MPV. Patient data were collected via chart review, and Cox proportional hazard and Kaplan-Meier method were used to assess the risk and estimate median overall survival.

RESULTS

We identified 188 patients treated with first-line pembrolizumab, with or without concurrent chemotherapy. There were 80 (42.6%) patients received pembrolizumab monotherapy, and 108 (57.4%) received pembrolizumab in combination with platinum-based chemotherapy. Patients whose MPV (∆MPV ≤ 0) decreased had hazard ratio (HR) = 0.64 (95% CI 0.43-0.94) for death with p = 0.023. Patients with ∆MPV ≤ - 0.2 fL (median), there was a 58% increase in the risk of developing irAE (HR = 1.58, 95% CI 1.04-2.40, p = 0.031). Thrombocytosis at baseline and cycle 2 was associated with shorter OS with p = 0.014 and 0.039, respectively.

CONCLUSION

Change in MPV after 1 cycle of pembrolizumab-based treatment was significantly associated with overall survival as well as the occurrence of irAEs in patients with metastatic NSCLC in the first-line setting. In addition, thrombocytosis was associated with poor survival.

An unusual presentation of extraskeletal vaginal Ewing sarcoma: A case report

Ewing sarcoma (ES) is a rare, aggressive malignancy that typically arises from bone and is seen more in adolescents and young adults. In contrast, extraskeletal Ewing sarcoma (EES) is more prevalent in adults and women [1,2]. There is no standard treatment for extraskeletal tumors, especially those in sensitive areas, such as the vagina, where resection may cause a large cosmetic or functional deformity. This case features a woman in her 20s who presented with painless vaginal bleeding and was found to have a 4 × 5 × 4-mm EES of the posterior vaginal wall. The presentation raised both reproductive and functional concerns, as the patient was young, sexually active and of childbearing age. The patient underwent treatment with radiation therapy and chemotherapy every 3 weeks. Given the lack of guidance and proclivity of EES to metastasize, it is paramount to proceed with standard-of-care treatment even if it is small and there is a lack of metastatic disease. For women with vaginal EES who are of childbearing age, brachytherapy rather than surgical resection may be a more favorable option when considering the location and the potential impact of vaginectomy.

The tumor microbiome as a predictor of outcomes in patients with metastatic melanoma treated with immune checkpoint inhibitors

Emerging evidence supports the important role of the tumor microbiome in oncogenesis, cancer immune phenotype, cancer progression, and treatment outcomes in many malignancies. In this study, we investigated the metastatic melanoma tumor microbiome and potential roles in association with clinical outcomes, such as survival, in patients with metastatic disease treated with immune checkpoint inhibitors (ICIs). Baseline tumor samples were collected from 71 patients with metastatic melanoma before treatment with ICIs. Bulk RNA-seq was conducted on the formalin-fixed paraffin-embedded (FFPE) tumor samples. Durable clinical benefit (primary clinical endpoint) following ICIs was defined as overall survival ≥24 months and no change to the primary drug regimen (responders). We processed RNA-seq reads to carefully identify exogenous sequences using the {exotic} tool. The 71 patients with metastatic melanoma ranged in age from 24 to 83 years, 59% were male, and 55% survived >24 months following the initiation of ICI treatment. Exogenous taxa were identified in the tumor RNA-seq, including bacteria, fungi, and viruses. We found differences in gene expression and microbe abundances in immunotherapy responsive versus non-responsive tumors. Responders showed significant enrichment of several microbes including Fusobacterium nucleatum, and non-responders showed enrichment of fungi, as well as several bacteria. These microbes correlated with immune-related gene expression signatures. Finally, we found that models for predicting prolonged survival with immunotherapy using both microbe abundances and gene expression outperformed models using either dataset alone. Our findings warrant further investigation and potentially support therapeutic strategies to modify the tumor microbiome in order to improve treatment outcomes with ICIs.

A bioinformatics tool for identifying intratumoral microbes from the ORIEN dataset

Evidence supports significant interactions among microbes, immune cells, and tumor cells in at least 10-20% of human cancers, emphasizing the importance of further investigating these complex relationships. However, the implications and significance of tumor-related microbes remain largely unknown. Studies have demonstrated the critical roles of host microbes in cancer prevention and treatment responses. Understanding interactions between host microbes and cancer can drive cancer diagnosis and microbial therapeutics (bugs as drugs). Computational identification of cancer-specific microbes and their associations is still challenging due to the high dimensionality and high sparsity of intratumoral microbiome data, which requires large datasets containing sufficient event observations to identify relationships, and the interactions within microbial communities, the heterogeneity in microbial composition, and other confounding effects that can lead to spurious associations. To solve these issues, we present a bioinformatics tool, MEGA, to identify the microbes most strongly associated with 12 cancer types. We demonstrate its utility on a dataset from a consortium of 9 cancer centers in the Oncology Research Information Exchange Network (ORIEN). This package has 3 unique features: species-sample relations are represented in a heterogeneous graph and learned by a graph attention network; it incorporates metabolic and phylogenetic information to reflect intricate relationships within microbial communities; and it provides multiple functionalities for association interpretations and visualizations. We analyzed 2704 tumor RNA-seq samples and MEGA interpreted the tissue-resident microbial signatures of each of 12 cancer types. MEGA can effectively identify cancer-associated microbial signatures and refine their interactions with tumors.

Clinical markers of immunotherapy outcomes in advanced sarcoma

BACKGROUND

Despite immunotherapy's promise in oncology, its use for sarcoma remains challenging. There are no sarcoma-specific biomarkers for immune checkpoint inhibitors (ICI). Previously, we reported our institutional experience highlighting ICI activity in 29 patients with sarcoma. In this study, we explore responses to ICI based on ICI regimen and other covariates to identify significant clinical factors in advanced sarcoma outcomes.

METHODS

Patients in The Ohio State University Sarcoma Clinics were enrolled in the Sarcoma Retrospective ICI database from January 1, 2015 through November 1, 2021. Data included treatment regimen (single-agent ICI or ICI + combination) along with clinical covariates. ICI + combination was further categorized into ICI + medication, ICI + radiation, ICI + surgery, or ICI + multiple (more than 2 modalities). Statistical analysis included log-rank tests and proportional hazard regression. The primary objective was to evaluate overall survival (OS) and progression-free survival (PFS).

RESULTS

Of the patients in the database, 135 met inclusion criteria. We demonstrated improved OS in patients treated with ICI + combination (p = 0.014, median 64 weeks), but no effect on PFS (p = 0.471, median 31 weeks). Patients with a documented immune-related adverse event (irAE) of dermatitis had improved OS, but only in the ICI + combination cohort (p = 0.021). Patients who received single-agent ICI and whose change in the neutrophil-to-lymphocyte ratio (NLR) was less than 5 had an improved OS (p = 0.002); this was not seen in patients who received ICI + combination therapy (p = 0.441). There were no differences in OS based on age, gender, histology, or subcategories of ICI + combination. This was not the case for PFS; patients who received any ICI regimen and were younger than 70 had a worse PFS (p = 0.036) compared with their older counterparts in this dataset. Patients who developed an irAE, specifically colitis (p = 0.009), hepatitis (p = 0.048), or dermatitis (p = 0.003), had an improved PFS. There were no differences in PFS based on ICI regimen (or subcategories of ICI + combination), gender, histology, change in NLR, or grade of irAE.

CONCLUSIONS

This retrospective study demonstrates that ICI + combination therapy can improve OS in some patients with advanced sarcoma. This is consistent with our prior results of ICI in sarcoma.

Emerging Trends in Immunotherapy for Adult Sarcomas

Soft-tissue sarcomas (STS) are a rare and heterogeneous group of malignant tumors that arise from the oncogenic transformation of mesenchymal tissue. There are over 100 distinct STS histological and molecular subtypes with unique clinical, therapeutic, and prognostic features with variable responses to therapy regimens. Given the quality-of-life concerns and limited efficacy with current regimens, including cytotoxic chemotherapy, there is a need for novel therapies and regimens to treat advanced STS. Although immune checkpoint inhibitors have demonstrated significant improvements in survival outcomes in other cancer types, there remains ambiguous data on the impact of immunotherapy in sarcoma. Biomarkers like PD-1/PD-L1 are not always predictive of outcomes. Therefore, researching emerging novel therapies, such as CAR-T and adoptive cell therapies, is critical to understanding STS biology, STS tumor immune microenvironment immunomodulatory strategies that improve immune response, and survival outcomes. We discuss the underlying biology of the STS tumor immune microenvironment, immunomodulatory strategies that augment pre-existing immune responses, and novel approaches to develop sarcoma-specific antigen-based therapies.

Nirogacestat, a γ-Secretase Inhibitor for Desmoid Tumors

BACKGROUND

Desmoid tumors are rare, locally aggressive, highly recurrent soft-tissue tumors without approved treatments.

METHODS

We conducted a phase 3, international, double-blind, randomized, placebo-controlled trial of nirogacestat in adults with progressing desmoid tumors according to the Response Evaluation Criteria in Solid Tumors, version 1.1. Patients were assigned in a 1:1 ratio to receive the oral γ-secretase inhibitor nirogacestat (150 mg) or placebo twice daily. The primary end point was progression-free survival.

RESULTS

From May 2019 through August 2020, a total of 70 patients were assigned to receive nirogacestat and 72 to receive placebo. Nirogacestat had a significant progression-free survival benefit over placebo (hazard ratio for disease progression or death, 0.29; 95% confidence interval, 0.15 to 0.55; P<0.001); the likelihood of being event-free at 2 years was 76% with nirogacestat and 44% with placebo. Between-group differences in progression-free survival were consistent across prespecified subgroups. The percentage of patients who had an objective response was significantly higher with nirogacestat than with placebo (41% vs. 8%; P<0.001), with a median time to response of 5.6 months and 11.1 months, respectively; the percentage of patients with a complete response was 7% and 0%, respectively. Significant between-group differences in secondary patient-reported outcomes, including pain, symptom burden, physical or role functioning, and health-related quality of life, were observed (P≤0.01). Frequent adverse events with nirogacestat included diarrhea (in 84% of the patients), nausea (in 54%), fatigue (in 51%), hypophosphatemia (in 42%), and maculopapular rash (in 32%); 95% of adverse events were of grade 1 or 2. Among women of childbearing potential receiving nirogacestat, 27 of 36 (75%) had adverse events consistent with ovarian dysfunction, which resolved in 20 women (74%).

CONCLUSIONS

Nirogacestat was associated with significant benefits with respect to progression-free survival, objective response, pain, symptom burden, physical functioning, role functioning, and health-related quality of life in adults with progressing desmoid tumors. Adverse events with nirogacestat were frequent but mostly low grade. (Funded by SpringWorks Therapeutics; DeFi ClinicalTrials.gov number, NCT03785964.).

Abstract P4-09-10: Spatial protein and RNA expression in tumor, immune and stromal cells in BRCA1/2 mutated metastatic breast cancer

Background: Spatial transcriptomics and proteomics are cutting-edge techniques that allow for quantification of RNA and protein expression within separate cell populations or regions of interest in a tissue biopsy specimen. We aimed to independently characterize the tumor cells and immune infiltrate in metastatic site biopsy specimens from patients with somatic or germline BRCA1/2 mutations. Methods: We performed spatial transcriptomics and proteomics using the Nanostring GeoMx Digital Spatial Profiler (DSP) on 9 formalin-fixed paraffin-embedded (FFPE) tissue biopsy specimens from 5 patients with metastatic breast cancer and a known somatic or germline BRCA1/2 mutation. Each patient had 1-3 separate metastatic site tissue biopsy specimens. Cell populations of interest were delineated with fluorescently labeled antibodies to pan-cytokeratin on tumor cells, CD45 of immune cells, and a nuclear stain. On each sample, 4-5 regions of interest (ROIs) were selected near the interface of the metastatic tumor deposit and surrounding normal tissue. Each ROI was segmented into 3 areas of interest (AOIs): pan-cytokeratin-positive tumor cells, CD45-positive immune cells, and the remaining stromal cells negative for both pan-cytokeratin and CD45. Data was background corrected and normalized with internal negative and positive internal controls. Relative abundance of immune cell subtypes was derived from CD45+ cell gene expression data using the TIMER algorithm. Results: The expression of 57 proteins and 84 RNAs was quantified in each of the 396 AOIs. Separate analysis of CD45+ cells, pan-cytokeratin cells, and stromal cell populations confirmed expected differential expression of immune, tumor and stromal markers, respectively. Protein expression of the estrogen receptor (ER) and progesterone receptor (PR) on pan-cytokeratin-positive tumor cells using the DSP correlated with pathologist reviewed immunohistochemistry (IHC) for ER and PR. Significant differential expression was found within each cell population between hormone receptor (HR) positive and negative cohorts, including enrichment for S100B in HR negative samples. Comparison will be shown for expression of 14 overlapping genes/proteins. Immune cell compartment gene expression deconvolution showed heterogeneity in the relative proportion of infiltrating immune cell subtypes between samples and also between ROIs within a sample. Changes in gene and protein expression from a patient with 3 serial biopsy specimens can be tracked with substantial heterogeneity across distinct AOIs within individual specimens and across metastatic sites.. Conclusions: Spatial transcriptomics and proteomics is feasible for concurrent, relative quantification of protein and gene expression in tumor, immune, and stromal cells in FFPE tissue biopsies from patients with metastatic breast cancer harboring germline or somatic BRCA1 or BRCA2 mutations. Heterogeneity within individual samples and across serial time points offers opportunity for methods development in the analyses and interpretation of spatial transcriptomic/proteomic data.

Citation Format: Katharine A. Collier, Katherine Miller, Zaibo Li, Jesse Westfall, David Tallman, Mark Vater, Gabriel Tinoco, Elaine Mardis, Daniel Stover. Spatial protein and RNA expression in tumor, immune and stromal cells in BRCA1/2 mutated metastatic breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-09-10.

Metastatic sporadic paraganglioma with EWSR1::CREM gene fusion: A unique molecular profile that expands the phenotypic diversity of the molecular landscape of the EWSR1::CREM gene fusion positive tumors

Chromosomal translocations with gene fusions are uniquely rare events in paraganglioma, mostly involving UBTF::MAML3 gene fusion. Precedent literature suggests that tumors involving MAML3 gene fusion correlate with poor clinical outcomes. Herein, we report a case of metastatic sporadic paraganglioma harboring EWSR1::CREM gene fusion in a 36-year-old male, that has not been previously described. The patient presented with large paraspinal mass that was resected the same year. Tumor recurred 3-years later and on further work-up, patient was found to have metastases involving both lungs. Histopathologic evaluation of the original primary tumor showed tightly packed irregular nests and cords of cells containing palely eosinophilic cytoplasm. Features considered atypical included: areas of solid growth pattern, coagulative tumor necrosis, focal cellular atypia and angiolymphatic invasion were also identified. By immunohistochemistry, the tumor cells were positive for synaptophysin and chromogranin and negative for keratin. The S100 stain highlights the sustentacular cells and the Ki-67 proliferation index of 15%. The recurrence specimen was similar but showed increased cellularity, atypia, necrosis, and proliferative activity (Ki-67 proliferation index of 35%). CT guided biopsy of the right lung lesion was consistent with metastasis. Next generation sequencing identified EWSR1::CREM fusion. The breakpoints were found in chromosome 22: 29683123 for EWSR1 exon 7 (NM_005243.3) and at chromosome 10:35495823 for CREM exon 6 (NM_001267562.1). Fluorescence in situ hybridization for EWSR1 gene rearrangement was positive. In summary, we report a case of metastatic paraganglioma with EWSR1::CREM gene fusion, not previously described in this entity, and expands on the phenotypic diversity within the genetic landscape of EWSR1::CREM gene fusion positive tumors.

Case report: The power of immunotherapy in advanced cutaneous squamous cell carcinoma

We describe the case of a neglected cutaneous squamous cell carcinoma with extensive facial involvement. The patient is a male in his late 70s who presented to dermatology with a large destructive facial mass that had increased in size gradually over 3 years and then rapidly proliferated, consuming a large portion of his left maxillofacial region. While the immediate reaction was referral to hospice care, medical oncology recommended treatment with cemiplimab, an immune checkpoint inhibitor. Collaboration with multiple providers facilitated the delivery of a multidisciplinary approach utilizing immunotherapy with QUAD shot radiotherapy. The immunotherapy treatment resulted in a dramatic disease regression, but the large facial anatomical defect caused by the carcinoma remained. The patient is undergoing reconstructive surgeries. This case illustrates the potential for significant response with immune checkpoint inhibitors delivered in combination with cyclical hypofractionated radiation therapy for patients with cutaneous squamous cell carcinoma, even in very advanced disease.

Sinonasal teratocarcinosarcoma: a therapeutic dilemma

Sinonasal teratocarcinosarcomas (SNTCSs) are rare and aggressive malignant tumours with histological features of the three embryonic layers. They have an elevated local recurrence rate, risk of metastasis and mortality. Moreover, the therapeutic options are limited, and optimal management is not yet clear. As fewer than 150 cases have been reported, therapeutic strategies remain a clinical challenge. Here, we discuss a case of a large SNTCS successfully treated with surgical resection followed by concurrent chemotherapy and radiation. Despite the significant size of the tumour and the inferred high recurrence risk, the patient has had no recurrence over the past 45 months. Although the optimal treatment of SNTCS is not clearly outlined, the very limited data suggests that a multidisciplinary approach with surgery, radiation and chemotherapy is the best option for patients.

Clinical markers of immunotherapy outcomes in sarcoma

11578

Background: Despite immunotherapy’s promise in oncology, its use for sarcoma remains challenging. There are no sarcoma-specific biomarkers for immune checkpoint inhibitors (ICI). Previously, we reported our institutional experience highlighting ICI activity in 29 patients with sarcoma. In this updated study, we further explore responses to ICI based on ICI regimen and other covariates to identify significant clinical factors in sarcoma outcomes. Methods: Patients in the Ohio State University Sarcoma clinics were enrolled in the Sarcoma Retrospective ICI database from January 1, 2015 through November 1, 2021. Data included treatment regimen (single agent ICI or ICI+combination) along with covariates: stage, age, gender, histology, change in neutrophil-to-lymphocyte ratio (NLR), number of cycles of ICI and immune-related adverse events (irAE). ICI+combination was further categorized into ICI+chemotherapy, ICI+radiation, ICI+surgery or ICI+multiple (more than 2 modalities). Statistical analysis included log rank tests and proportional hazard regression. The primary objective was to evaluate overall survival (OS) and progression-free survival (PFS). Results: One hundred and thirty-five patients met inclusion criteria. We demonstrated improved OS in patients treated with ICI+combination (p = 0.014, median 64 weeks), but no effect on PFS (p = 0.471, median 31 weeks). Whether patients had received single agent or combination ICI, those who received more than 3 cycles of ICI had an improved OS and PFS (p < 0.05 for both). Patients who received single-agent ICI and whose change in NLR was less than 5 had an improved OS (p = 0.002); this was not seen in patients who received ICI+combination therapy (p = 0.441). Patients who had a documented irAE of dermatitis had improved OS but only in the ICI+combination cohort (p = 0.021). There were no differences in OS based on age, gender, histology or sub-categories of ICI+combination. This was not the case for PFS; patients who received any ICI regimen and were younger than 70 had a worse PFS (p = 0.036). Patients who developed an irAE, specifically colitis (p = 0.009), hepatitis (p = 0.048) and dermatitis (p = 0.003) had an improved PFS. There were no differences in PFS based on ICI regimen (or sub-categories of ICI+combination), gender, histology, change in NLR or grade of irAE. Our ICI cohort results are consistent with historical data from our previous study. Further, irAEs are similar to historical data. Conclusions: This retrospective study demonstrates that ICI+combination therapy can improve OS in sarcoma. This is consistent with our prior results of ICI in sarcoma. Benefits in OS/PFS were seen in patients who received more than 3 cycles of ICI and developed certain irAE. These results can direct the optimal duration of ICI therapy. Those with decreased change in NLR also had improved OS, demonstrating a potential prognostic biomarker. Further studies are needed to validate our findings.

Primary Intranodal Epithelioid Hemangioendothelioma with Molecular Confirmation

Epithelioid hemangioendothelioma (EHE) is a rare low-grade malignant vascular tumor with indolent biology, characterized by reciprocal t(1;3)(p36.6;q25) with resultant WWTR1::CAMTA1 gene fusion in the vast majority of cases, regardless of anatomic location. Only a small subset, exhibiting well formed vasoformative features will contain YAP1::TFE3 gene fusion. Primary intranodal EHE is exquisitely rare. We report a case in a 54-year-old male with persistent left groin mass with discomfort for nine months. A CT of the abdomen and pelvis showed a minimally enlarged left inguinal lymph node measuring 2.8 cm with no other masses or lymphadenopathy. PET/CT and MRI imaging of the abdomen showed no evidence of disease elsewhere. Sections showed an epithelioid vasoformative neoplasm, centrally necrotic and involving a lymph node. The cells were arranged in anastomosing cords with intracytoplasmic lumens, resembling "signet ring cells". By immunohistochemistry, the tumor cells were positive for vimentin, CD31, CD34, ERG and CAMTA1; and negative for AE1/3, CAM 5.2, KRT7, KRT20, desmin, actin, HMB-45 and S-100. Ki-67 proliferation index was estimated at <1%. Molecular studies including next generation sequencing (NGS) revealed the presence of WWTR1::CAMTA1 gene fusion, and fluorescence in situ hybridization for CAMTA1 (1p36.23) and WWTR1 (3p25.1) showed fusion signals, diagnostic of EHE. We highlight a rare occurrence of EHE in a lymph node exhibiting morphologic mimicry with metastatic carcinoma.

Immune checkpoint inhibitor-related thrombocytopenia: incidence, risk factors and effect on survival

INTRODUCTION

Immune checkpoint inhibitors (ICI) are associated with unique immune-related adverse events (irAEs). Immune-related thrombocytopenia (irTCP) is an understudied and poorly understood toxicity; little data are available regarding either risk of irTCP or the effect of irTCP on clinical outcomes of patients treated with ICI.

METHODS

We conducted a retrospective review of sequential cancer patients treated with ICI between 2011 and 2017 at our institution. All patients who received ICI alone or in combination with other systemic therapy in any line of treatment were included; those with thrombocytopenia ≥ grade 3 at baseline were excluded. We calculated the incidence of ≥ grade 3 irTCP and overall survival (OS). Patient factors associated with irTCP were assessed.

RESULTS

We identified 1,038 patients that met eligibility criteria. Overall, 89 (8.6%) patients developed grade ≥ 3 thrombocytopenia; eighteen were attributed to ICI (1.73% overall). Patients who developed grade ≥ 3 irTCP had worse overall survival compared to those whose thrombocytopenia was unrelated to ICI (4.17 vs. 10.8 month; HR. 1.94, 95% CI 1.13, 3.33; log-rank p = 0.0164). Patients with grade ≥ 3 irTCP also had worse survival compared to those without thrombocytopenia (4.17 vs. 13.31 months; HR 2.22, 95% CI 1.36, 3.62; log-rank p = 0.001). The incidence of irTCP appeared lowest among those treated with PD-1/L1 monotherapy (p = 0.059) and was not associated with cancer type, smoking status, age, gender, race, or line of therapy.

CONCLUSIONS

Unlike other irAEs, we found that irTCP was associated with worse overall survival. The incidence of irTCP appeared lowest among those treated with PD-1/L1 monotherapy.

Randomized Prospective Trial Exploring the Impact of Structured Journaling in Patients With Sarcoma on the Management of Treatment-Related Adverse Events

Treatment-related adverse events associated with systemic anticancer therapy (SACT) can deter patients with sarcoma from completing treatment. With self-monitoring, patients may be better empowered to self-advocate for improved symptom management. We hypothesized that by incorporating journaling, a structured form of self-monitoring, care team communication, and symptom management would improve. We thus designed a prospective randomized trial exploring journaling as a therapeutic adjuvant for symptom management (NCT03258892).

Association of Combination of Conformation-Specific KIT Inhibitors With Clinical Benefit in Patients With Refractory Gastrointestinal Stromal Tumors: A Phase 1b/2a Nonrandomized Clinical Trial

IMPORTANCE

Many cancer subtypes, including KIT-mutant gastrointestinal stromal tumors (GISTs), are driven by activating mutations in tyrosine kinases and may initially respond to kinase inhibitors but frequently relapse owing to outgrowth of heterogeneous subclones with resistance mutations. KIT inhibitors commonly used to treat GIST (eg, imatinib and sunitinib) are inactive-state (type II) inhibitors.

OBJECTIVE

To assess whether combining a type II KIT inhibitor with a conformation-complementary, active-state (type I) KIT inhibitor is associated with broad mutation coverage and global disease control.

DESIGN, SETTING, AND PARTICIPANTS

A highly selective type I inhibitor of KIT, PLX9486, was tested in a 2-part phase 1b/2a trial. Part 1 (dose escalation) evaluated PLX9486 monotherapy in patients with solid tumors. Part 2e (extension) evaluated PLX9486-sunitinib combination in patients with GIST. Patients were enrolled from March 2015 through February 2019; data analysis was performed from May 2020 through July 2020.

INTERVENTIONS

Participants received 250, 350, 500, and 1000 mg of PLX9486 alone (part 1) or 500 and 1000 mg of PLX9486 together with 25 or 37.5 mg of sunitinib (part 2e) continuously in 28-day dosing cycles until disease progression, treatment discontinuation, or withdrawal.

MAIN OUTCOMES AND MEASURES

Pharmacokinetics, safety, and tumor responses were assessed. Clinical efficacy end points (progression-free survival and clinical benefit rate) were supplemented with longitudinal monitoring of KIT mutations in circulating tumor DNA.

RESULTS

A total of 39 PLX9486-naive patients (median age, 57 years [range, 39-79 years]; 22 men [56.4%]; 35 [89.7%] with refractory GIST) were enrolled in the dose escalation and extension parts. The recommended phase 2 dose of PLX9486 was 1000 mg daily. At this dose, PLX9486 could be safely combined with 25 or 37.5 mg daily of sunitinib continuously. Patients with GIST who received PLX9486 at a dose of 500 mg or less, at the recommended phase 2 dose, and with sunitinib had median (95% CI) progression-free survivals of 1.74 (1.54-1.84), 5.75 (0.99-11.0), and 12.1 (1.34-NA) months and clinical benefit rates (95% CI) of 14% (0%-58%), 50% (21%-79%), and 80% (52%-96%), respectively.

CONCLUSIONS AND RELEVANCE

In this phase 1b/2a nonrandomized clinical trial, type I and type II KIT inhibitors PLX9486 and sunitinib were safely coadministered at the recommended dose of both single agents in patients with refractory GIST. Results suggest that cotargeting 2 complementary conformational states of the same kinase was associated with clinical benefit with an acceptable safety profile.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02401815.

Larotrectinib in a Patient With Advanced Pleomorphic Liposarcoma of the Uterus

Pleomorphic liposarcoma of the uterus (PLU) is an extremely rare disease with poor prognosis. Limited treatment options exist for these patients, and disease recurrence usually occurs rapidly within months of initial diagnosis. Few case reports of metastatic PLU are available in the literature. We describe a 70-year-old woman who presented with a large uterus and ovarian mass on imaging and negative serum tumor markers and endometrial biopsy. Staging revealed localized disease. Surgical resection revealed PLU on pathology. Immunohistochemistry was negative for smooth muscle actin (SMA), S100, and MDM2, and positive for CD10 and cyclin-D1. She was treated with adjuvant therapy and experienced disease recurrence in the liver at 15 months from surgery. Genetic testing of the metastasis showed IQGAP-NTRK3 gene fusion. She was given entrectinib but continued to show progression in the liver. Right partial hepatectomy was performed, showing positivity for CD10, BCL-1, MDM2, and SMA on tumor staining. Treatment was switched to pazopanib with disease progression in the neck. She was treated with larotrectinib last, showing no disease progression and adequate tolerance of therapy after 18 months of this treatment. This is the first case in the literature of metastatic PLU with NRTK3 fusion treated with sequential first-generation NRTK inhibitors. More case reports are needed to identify commonalities and therapeutic options. Genetic testing in all PLU cases is needed for targeted therapy approaches.

Results of a phase 1 dose-escalation study of AMV564, a novel T-cell engager, alone and in combination with pembrolizumab in patients with relapsed/refractory solid tumors

2555

Background: Myeloid-derived suppressor cells (MDSC) contribute to an immunosuppressive tumor environment and are a barrier to immune therapy. CD33 signaling in immature myeloid cells promotes expansion of MDSC and production of immunosuppressive factors. AMV564 is a potent T cell engager that selectively depletes MDSC while promoting T cell activation and proliferation, via preferential binding to areas of high CD33 density. Methods: In this 3+3 dose escalation study, patients with relapsed/refractory solid tumors for whom no recognized standard therapy exists received AMV564 once daily via subcutaneous (SC) injection on Days 1-5 and 8-12 of a 21-day cycle, either alone or in combination with pembrolizumab (200 mg IV q3w). Study endpoints included incidence and severity of adverse events (AEs), pharmacokinetics (PK), and preliminary anti-tumor activity (using RECISTv1.1 criteria). Results: As of January 29, 2021, 20 patients were dosed in 3 monotherapy dose cohorts (15, 50, and 75 mcg/day), and 10 patients were dosed in 3 combination therapy cohorts (5, 15, and 50 mcg/day). Enrolled patients were: median age 64 years, 47% female, had received median 3.5 prior lines of therapy; 7 patients (35%) had received prior checkpoint inhibitor therapy (6 monotherapy patients, 1 combination therapy patient). No dose-limiting toxicity was observed and a maximum-tolerated dose was not reached in either the monotherapy or combination therapy cohorts. The most common treatment-related AEs (occurring in > 10% of patients, in order of decreasing frequency) in the monotherapy cohort were pyrexia, injection site reactions, fatigue, anemia, hypotension, pruritis, chills, and nausea. There were 2 cases of grade 2 cytokine release syndrome (CRS) at 75 mcg/day, both of which resolved after anti-IL6 therapy and study treatment was resumed. The most common treatment-related AEs in the combination cohorts (> 10% frequency) were injection site reaction, pyrexia, fatigue, pruritis, and anemia. No cases of CRS were noted in the combination cohorts. In preliminary PK analysis, estimated median plasma half-life for AMV564 after SC injection was > 48 hours, with dose-related increases in peak plasma concentration. Clinical responses were seen with monotherapy and combination therapy, including a complete response (CR) in a monotherapy-treated patient with ovarian cancer refractory to all standard therapies and anti-PD-1 therapy. Conclusions: AMV564 was well tolerated across multiple dose levels as monotherapy and in combination with pembrolizumab. Subcutaneous injection resulted in clinically relevant plasma exposures. Single-agent and combination therapy anti-tumor activity was observed. Further exploration of AMV564 clinical efficacy in expansion cohorts is ongoing. Clinical trial information: NCT04128423.

Immune checkpoint inhibitor-related thrombocytopenia: Incidence, risk factors, and effect on overall survival

e14549

Background: Immune checkpoint inhibitors (ICI) are a standard of care therapy for patients with many different cancers. ICI are generally well tolerated but are associated with unique immune-related adverse events (irAEs). Immune-related thrombocytopenia (irTCP) is an understudied and poorly understood toxicity and risk factors for irTCP are unknown. Although other irAE have been associated with clinical benefit, little data is available regarding either risk of irTCP or the effect of irTCP on clinical outcomes of patients treated with ICI. Methods: We conducted a retrospective review of sequential patients with any solid or hematologic cancer treated with ICI between 2011 and 2017 at The Ohio State University Comprehensive Cancer Center. All patients who received ICI alone or in combination with other systemic therapy in any line of treatment were included; those with thrombocytopenia ≥ grade 3 at baseline were excluded. Thrombocytopenia grading was performed utilizing the Common Terminology Criteria for Adverse Events version 5.0. Attribution to ICI was defined as timing after ICI initiation, lack of alternative causes, and improvement with either holding treatment or use of immune suppressive therapy. Overall survival (OS) was calculated from the date of initiation of ICI to death from any cause or date of the last follow-up examination. Cox proportional hazard models were used to examine the associations between platelet categories with OS. Median OS was estimated using Kaplan-Meier method with 95% CI. Results: We identified 1,038 patients treated with ICI therapy after excluding patients with baseline thrombocytopenia. The median age was 61.4; 613 (59.1%) were male and 613 (59.1%) had history of smoking. The most common cancer types were melanoma (n = 337, 32.5%), lung (n = 213, 20.5%), and renal cell carcinoma (n = 114, 11%). The most common ICI were PD1/L1 (n = 729, 70.2%) and CTLA4 (n = 191, 18.4%). Overall, 89 (8.6%) patients developed grade ≥3 thrombocytopenia; twenty were attributed to ICI (1.93% overall). Patients who developed ≥3 irTCP had worse overall survival compared to those whose thrombocytopenia was unrelated to ICI (5.45 vs 11.3 months; HR. 2.077, 95% CI 1.231, 3.503; log-rank p = 0.005). Patients with ≥3 irTCP also had shorter survival compared to those without thrombocytopenia of any etiology (5.45 vs 13.3 months; HR 2.247, 95% CI: 1.414, 3.571; p < 0.001). irTCP was more common among those treated with PD1/L1 (p = 0.03) but was not associated with cancer type, smoking status, age, gender, race, or line of therapy. Conclusions: Type of immunotherapy is related to irTCP, whereas cancer type and line of therapy are not. Unlike other irAEs, we found that irTCP was associated with shorter overall survival. These findings provide important insight into a poorly understood and rare toxicity. irTCP should be evaluated in more extensive studies to better inform clinical decision making.

P10015/SARC033: A phase 2 trial of trametinib in patients with advanced epithelioid hemangioendothelioma (EHE)

11503

Background: EHE is a rare vascular cancer arising in liver, lung, soft tissue and bone. The natural history of metastatic disease varies considerably from indolent growth over years to rapid growth with fatal outcome in months. Treatment of patients (pts) with metastatic EHE with antiangiogenic therapy induces tumor response in a minority of pts, and median PFS is 6-12 months. TAZ-CAMTA1 translocation results in activation of MAPK pathway and is an oncogenic driver in EHE. We sought to evaluate the effect of MEK inhibition using trametinib in pts with unresectable EHE. Methods: A phase 2 trial of trametinib 2 mg daily was conducted in pts with EHE though the Experimental Therapeutics Clinical Trials Network supported by NCI in collaboration with SARC. Additional support was provided by the EHE Rare Cancer Charity and the EHE Foundation. Pts had to have evidence of objective tumor progression or EHE-related pain requiring narcotics for relief prior to enrollment. Presence of TAZ-CAMTA1 translocation was analyzed by fusion-FISH after enrollment. Primary trial endpoint was objective response rate (ORR) per RECIST1.1 with at least 1 objective response required in the 1st 13 pts to expand enrollment to 27. The trial was amended after stage 1 to continue enrollment to 27 pts with TAZ-CAMTA1 detected by FISH with goal of >4 objective responses in this group. Secondary objectives were PFS and OS rates, safety and change in pt-reported global health and pain scores per PROMIS questionnaires. Results: 43 pts were enrolled between 6/2017 – 9/2020 across 10 sites and 41 started therapy. TAZ-CAMTA1 fusion was detected in 26, not detected in 7, test failed in 5 and was not performed due to insufficient tumor in 5. Median pt age was 54 (range 22-81 yrs) and 11 were >65 yrs; 25 were female; ECOG was 0 in 23, 1 in 16 and 2 in 3 pts. Most pts experienced reduction in tumor size. ORR per RECIST was 7% (3/41); in pts with TAZ-CAMTA1 detected, the ORR was 0% (0/26). Mean pain intensity and interference scores had a statistically significant improvement and global quality of life scores did not statistically change after 4 weeks of therapy. 17 pts remained on treatment > 6 months and 7 > 12 months. 25 pts stopped trametinib due to EHE progression, 6 died during treatment, 6 withdrew from treatment, 3 stopped drug due to adverse event and 1 is on treatment. The most common AEs related to trametinib were rash, fatigue, nausea/vomiting, diarrhea, alopecia and edema; Grade >3 AEs included anemia, dyspnea, hypoxia, hypotension, syncope and dermatitis. Conclusions: To our knowledge, this is the largest prospective clinical study focused on pts with EHE. Although the trial did not meet the ORR goal, stable disease > 6 months was seen in 40% of pts, and EHE-related pain improved on treatment. Trametinib was associated with expected cutaneous and GI adverse effects. Additional pt-reported outcomes and biomarkers of inflammation are undergoing analysis. Clinical trial information: NCT03148275.

Proton pump inhibitor use (PPI) in patients treated with immune checkpoint inhibitors (ICI) for advanced cancer: Survival and prior therapy

2633

Background: Emerging data suggest that concomitant medications (CM) influence response to ICI. CM impact the host microbiome which may mitigate tumor-immune responsiveness. PPI use in patients treated with ICI has been associated with worse survival. Few data exist regarding the effects of PPI use in terms of prior chemotherapy or in risk for immune related adverse events (irAE) (e.g., colitis). Methods: This retrospective study of patients with advanced cancer treated with ICI between 2011 and 2019 was conducted at The Ohio State University. Patients who received ICI as either single agent or combination were included. Clinical data was abstracted from chart review, including CM, toxicity, and survival. Overall survival (OS) was evaluated to date of death or last contact. Associations between OS and proton pump inhibitor (PPI) use were studied using log-rank tests and Cox regression analyses overall and by the groups of whether prior chemotherapy was administered and timing from chemotherapy to ICI. The associations between PPI and incidence of irAE (overall and colitis) were assessed by chi-square tests. Results: We identified 1,091 patients treated with ICI, of whom 415 (38%) received PPI at time of ICI. Most common cancers were NSCLC and melanoma; most common therapy was PD1/L1 (Table). PPI use was associated with shorter OS in patients treated as first line therapy (HR = 1.46, 95% CI = [1.11, 1.91], p=0.006) and in second line and beyond (HR = 1.30, 95% CI = [1.10, 1.53], p=0.002). PPI use was associated with shorter OS in patients treated with ICI for those without prior chemotherapy (HR = 1.47, 95% CI = [1.17, 1.86], p=0.001). When evaluated by timing from chemotherapy to ICI, PPI use was associated with shorter OS only in patients where last chemotherapy was > 1 year from ICI (HR = 1.99, 95% CI [1.15, 3.45], p=0.014) but not for patients with chemotherapy within 1 year of ICI (HR = 1.01, 95% CI = [0.79, 1.29], p=0.960). The use of PPI was not associated with incidence of irAE (p=0.317) or colitis in particular (p=0.781). Conclusions: PPI use was associated with shorter survival in patients treated with ICI across a broad variety of cancers and in first line of therapy or beyond. In patients with recent chemotherapy (<1 year), PPI use was not associated with survival, which may be due to disruption of the microbiome by chemotherapy. Further study is needed to determine the impact of CM (e.g, PPI), on outcomes of patients treated with ICI.[Table: see text]

The sarcoma microbiome as a diagnostic and therapeutic target

11541

Background: Sarcoma is a heterogeneous group of malignant tumors that consist of distinct histological and molecular subtypes, each with unique features. Despite immunotherapy’s promise in many cancers, immunotherapeutic approaches for sarcoma have had variable response rates. Evaluating the tumor microbiome is a promising new approach that aims to improve our understanding of the immunogenicity of sarcoma subtypes, leading to improved treatment options and better clinical outcomes. Methods: We utilized The Cancer Genome Atlas (TCGA) and Genome Tissue Expression (GTEx) database to obtain RNA sequencing (RNAseq) data to identify microbes in sarcoma samples (all subtypes available). Due to the large number of sarcoma subtypes, we focused on three groups: dedifferentiated liposarcoma (DDLPS), leiomyosarcoma (LMS) and “other,” representing all other sarcoma subtypes. We utilized ExoTIC, “Exogenous sequences in Tumors and Immune cells,” a tool recently developed by Dr. Daniel Spakowicz and Dr. Xaiokui Mo. ExoTIC takes raw RNAseq reads and carefully aligns to both human and non-human reference genomes to identify low-abundance microbes. Models of association were analyzed based on each of the three groups as well as all the samples: “All” group. We performed Cox proportional hazards regression to identify the microbes associated with overall survival (OS). Results: We evaluated 97 LMS, 56 DDLPS and 100 “other” RNAseq samples (Table). ExoTIC identified 1304 microbes, of which 431 were statistically associated with OS in the “All” group. Of these, 50 microbes were statistically associated only with DDLPS, 54 only with LMS (e.g., Candida dubliniensis, Mycobacterium avium, Streptococcus sp. Z15), and 46 with “other.” The presence of no organism was associated with improved survival. Median hazard ratios were largest in DDLPS (2.3), followed by “other” (2.1) and LMS (1.9). Only 18 microbes were found in the DDLPS, LMS and “All” groups, including Bacillus sp., Streptococcus lutetiensis, Clostridium tetani, and Pseudomonas sp. LTJR-52. Each was negatively correlated with survival with a median hazard ratio of 2.5. Conclusions: We found a specific relationship between microbial presence and histological sarcoma subtype (DDLPS, LMS), which also statistically correlated with OS. Assessing individual characteristics of a sarcoma histological subtype with its particular microenvironment (e.g., microbes) can lead to personalized treatment insights and improvements in outcomes. Our future research will consist of validating and correlation of the microbial profile of sarcoma subtypes with clinical outcomes retrospectively and prospectively. [Table: see text]

Guillain-Barre Syndrome Amid Osteosarcoma Treatment: A Therapeutic Dilemma and Literature Review

Guillain-Barre syndrome (GBS) is a clinical syndrome with multiple variants. GBS is defined as an acute demyelinating polyneuropathy commonly preceded by infection (bacterial or viral), trauma, or inflammatory processes, which triggers an autoimmune response that affects the peripheral nervous system. This case report describes a patient with high-grade osteosarcoma that completed neoadjuvant chemotherapy and underwent surgical resection with no immediate complications. Fourteen days after the surgery, the patient developed an acute inflammatory demyelinating polyradiculopathy consistent with GBS. As the five-year survival without chemotherapy is only around 20%, this challenging clinical scenario raised questions regarding adjuvant chemotherapy's safe completion in this setting.

Activity of PD1 inhibitor therapy in advanced sarcoma: a single-center retrospective analysis

BACKGROUND

Sarcomas constitute a heterogeneous group of tumors with different clinical behaviors and variable responses to systemic therapies. Recent immunotherapy studies with PD1 inhibitors (PD1i) show promising results with use in certain soft-tissue sarcomas; however, the clinical and molecular features that best predict response to PD1i remain unclear.

METHODS

Demographic, imaging, histologic, and genetic sequencing data was collected for sarcoma patients who received nivolumab or pembrolizumab (PD1i) treatment at our institution between January 1st 2015 and April 23rd 2018. The primary objective was to determine progression-free survival (PFS) in patients with advanced sarcomas receiving PD1i. Secondary objectives included determining overall survival (OS) and assessment of characteristics associated with response to PD1i. Fifty-six patients who were treated with PD1i therapy met inclusion criteria for this study.

RESULTS

Partial response towards PD1i treatment was seen in 3 in 26 evaluable patients, but no complete responses were observed (overall response rate 11.5%). Within this group of patients, the 90 day PFS was found to be 48.8%. In patients in whom PD1 expression was known, there was a statistically significant positive correlation between expression of PD1 and longer PFS and OS rates. Patients that were treated with more than four cycles of PD1i therapy were also more likely to have a greater OS.

CONCLUSIONS

This study suggests activity of PD1i in a pretreated cohort of advanced sarcoma patients, particularly for the subset of patients with PD1 positive tumors. Our results highlight the importance of further research to better target the optimal patient population and markers of response.

Patient-reported global health predicts adverse health outcomes in a cohort of patients with advanced sarcoma

e23547

Background: Given the rare nature of sarcoma cancers and the sometimes severe treatment-related effects of chemotherapy, many patients with sarcoma face quality of life issues during treatment. Unplanned hospital admission and emergency room (ER) visits can occur from uncontrolled symptoms and ultimately delay treatment regimens and negatively impact quality of life. The PROMIS Global Health v1.2 (PROMIS-10) surveys are validated tools to assess patients’ physical and mental well-being at the time of the survey. We sought to evaluate the correlation between PROMIS-10 scores and adverse outcomes of interest, including unplanned admissions/ED visits and patient mortality. Methods: All patients currently seen in the Sarcoma Clinics at Ohio State University routinely complete the PROMIS-10 survey at each clinic visit. For this pilot study, we collected the raw and normalized t-scores for PROMIS-10 surveys for all patients consented to The Ohio State University Sarcoma Registry (OSU-14242) from 6/1/2018 to 11/20/2019. We also collected data on unplanned hospital admission/ED visits and mortality data for each patient. Results: A total of 864 surveys for 112 patients were collected for the study period. The median number of surveys answered per patient was 6. Mean global physical t-scores (43.7 ± 8.5) and mental t-scores (47.9 ± 9.2) were lower than reference scores for the general US population (p < 0.001). 109 of 112 patients experienced an unplanned admission or ED visit during the study, with a total of 270 such encounters during the study period. PROMIS-10 scores were slightly but significantly lower for patients experiencing an admission or ED visit within 30 days of taking the survey (physical: 41.9 vs 44.1, p = 0.006; mental: 46.4 vs 48.2, p = 0.035). A total of 26 patients died during the study period; surveys completed prior to death were consistent with a greater level of physical and mental distress, with the median physical t-score = 34.9 (range: 23.5 – 50.8) and mental t-score = 43.5 (range: 33.8 – 67.6). Conclusions: We showed that we are able to obtain worthwhile data to objectively evaluate patients’ physical and mental well-being through survey data during cancer treatment. We are currently performing additional confirmatory analysis of the predictive value of the PROMIS-10 survey for adverse events and for treatment-related complications.

Development of urine metabolomic biomarkers for ifosfamide-induced encephalopathy (IIE) in soft tissue sarcoma patients

e23534

Background: In the treatment of sarcomas, high doses of ifosfamide in combination with other chemotherapeutic agents remains a backbone of cytoreductive therapy. Unfortunately, IIE remains a prevalent treatment side effect with a reported prevalence of 10-20%. Although mild hypoalbuminemia has previously been implicated as a risk factor, its risk contribution is modest. There are no clinically significant biomarkers which may help identify IIE patents. Given the correlation with hypoalbuminemia to renal function, we hypothesized that urinary metabolites may serve as potential early biomarkers for IIE. Here we report our interim biomarker findings as part of our sarcoma metabolomic biocollection protocol. Methods: All sarcoma patients that received ifosfamide were identified (2011-2020) through a sarcoma registry (OSU-14242). Development of IIE was obtained through chart review. For consented patients undergoing adriamycin and ifosfamide treatment, urine samples were obtained over the course of 5 days and two treatment cycles (OSU IRB: 2014C0181). Urine samples were subjected to targeted metabolomic analysis for known ifosfamide metabolites and untargeted metabolomic profiling. LC-MS was performed on a Sciex TripleTOF 5600 and data preprocessing with XCMS. For each metabolite, mean abundance and slope, as determined by linear regression across all time points, was compared to development of IIE coded as a binary variable. Results: A total of 70 sarcoma patients were identified, of whom 11 developed IIE for a prevalence of 15.7%. Baseline values at the start of ifosfamide treatment were a mean albumin of 3.7 g/dL (+/- 0.38) and a mean serum creatinine of 0.79 mg/dL (+/- 0.26). Both values are within our “normal range”. For seven of these patients, of whom one developed IIE, we successfully collected additional metabolomic profiling. From these data, 6,030 features (representing metabolites or metabolite fragments) were measured. Time course plots of drug metabolites for which pure standards were run showed an increase of expected chemotherapy-related metabolites at the beginning of each cycle, with inter- and intra-patient variability. IIE was associated with 70 metabolite features (by mean abundance, FDR < 5%). Metabolite identification of putative features based on tandem mass spectrometry is in process. Conclusions: This pilot study indicates that urine metabolomic analysis is feasible and may identify IIE biomarkers. We expect to confirm these results once ongoing specimen analysis is complete.

Sarcoma Treatment Efficacy Portal (STEP): A novel informatics portal providing real-time, real-world outcomes to clinicians

e23538

Background: There are currently no informatics tools that are capable of providing complex clinical decision support using real-world outcomes (RWO) for patients with sarcoma. Although existing nomograms can provide prognostic scores based on clinical or genomics features, they typically are static and lack the ability to compare outcomes for patients managed with alternative treatment strategies. To address this need, we present STEP, a Sarcoma Treatment Efficacy Portal, a web-based tool designed for real-time exploration and visualization of patient data with the potential to be integrated into clinical decision workflows during outpatient visits. Methods: At The Ohio State University, clinical histories and omics data for sarcoma patients are captured in our prospective Sarcoma Registry (NCT0267796). STEP is an interactive web-based tool built in R/Shiny and supported by a pipeline written Python that processes, transforms, and caches clinical data extracted from the Sarcoma Registry in near real-time. Protected health information (PHI) is stored on a secure HIPAA compliant server behind the hospital firewall and migrated to a secure, deidentified staging database. Results: The STEP system is powered by detailed treatment specific data elements that are continuously abstracted for over 400 patients with bone and soft tissue sarcoma. This consists of manually annotated clinical histories in addition to nearly 10 million discrete data points are pulled from the EHR (labs, ICD-9/10 codes, medications, omics data). Importantly, STEP includes a cohort builder which allows users to define a treatment group of interest though any number of variables including tumor histology, chemotherapy, and omic features of interest. For any predefined cohort, STEP can provide information on overall survival and response to a variety of treatments. It also provides sorting mechanisms for identifying candidate treatments. A secure web interface allows a simple integration into a busy clinic flow. Conclusions: STEP provides a first in class, convenient, clinician friendly platform for delivering access to real-time, real-world treatment outcomes (RWO) in patients with a diagnosis of bone or soft tissue sarcoma. Additional usability testing is forthcoming.

Inferring the role of the microbiome on survival in patients treated with immune checkpoint inhibitors: causal modeling, timing, and classes of concomitant medications

BACKGROUND

The microbiome has been shown to affect the response to Immune Checkpoint Inhibitors (ICIs) in a small number of cancers and in preclinical models. Here, we sought to broadly survey cancers to identify those in which the microbiome may play a prognostic role using retrospective analyses of patients with advanced cancer treated with ICIs.

METHODS

We conducted a retrospective analysis of 690 patients who received ICI therapy for advanced cancer. We used a literature review to define a causal model for the relationship between medications, the microbiome, and ICI response to guide the abstraction of electronic health records. Medications with precedent for changes to the microbiome included antibiotics, corticosteroids, proton pump inhibitors, histamine receptor blockers, non-steroid anti-inflammatories and statins. We tested the effect of medication timing on overall survival (OS) and evaluated the robustness of medication effects in each cancer. Finally, we compared the size of the effect observed for different classes of antibiotics to taxa that have been correlated to ICI response using a literature review of culture-based antibiotic susceptibilities.

RESULTS

Of the medications assessed, only antibiotics and corticosteroids significantly associated with shorter OS. The hazard ratios (HRs) for antibiotics and corticosteroids were highest near the start of ICI treatment but remained significant when given prior to ICI. Antibiotics and corticosteroids remained significantly associated with OS even when controlling for multiple factors such as Eastern Cooperative Oncology Group performance status, Charlson Comorbidity Index score, and stage. When grouping antibiotics by class, β-lactams showed the strongest association with OS across all tested cancers.

CONCLUSIONS

The timing and strength of the correlations with antibiotics and corticosteroids after controlling for confounding factors are consistent with the microbiome involvement with the response to ICIs across several cancers.

Re-evaluating the neutrophil-to-lymphocyte ratio: Machine learning-based variable selection for predicting survival at twelve months in late-stage cancer patients receiving immunotherapy

e18201

Background: Neutrophil to Lymphocyte Ratio (NLR) is prognostic for cancer patients treated with immune checkpoint inhibitors (ICI). We showed the change in NLR early during treatment to be a stronger, curvilinear predictor, i.e. patients with an intermediate change in NLR performed better than those with large decreases or increases. This led us to re-examine whether NLR is an optimal predictor of overall survival (OS). Methods: A retrospective review of 467 patients with advanced cancer who received ICIs from 2011 to 2017 at the Ohio State University was performed with IRB approval. NLR was collected at the initiation of ICI and on-treatment (median 21, IQR 8 days) and calculated as ratio of absolute neutrophil to lymphocyte counts. Variable selection machine-learning algorithms included fast and frugal decision trees and random forest, performed in R. Results: The machine-learning algorithm fast and frugal decision trees identified the ratio of NLR on treatment to baseline NLR, the NLR on treatment, the change in NLR and the cubic change in NLR to be the most informative predictors of survival at 12 months. A random forest algorithm identified the same four variables as the most important for prediction accuracy. Age, sex and cancer type were the least informative predictors in the model, suggesting the on-treatment NLR variables are of value across wide range of demographics. Conclusions: NLR measured during treatment, and its derivative values of the ratio to baseline, change from baseline, and the cubic change from baseline, hold more predictive value than NLR measured at baseline. Common control variables such as age, and sex showed little effect on the model, suggesting on-treatment NLR is useful across wide demographic space. [Table: see text]

Effect of concomitant medications on overall survival in patients with cancer undergoing immunotherapy

94

Background: The response to Immunotherapy (IO) is known to be affected by concomitant medications including corticosteroids and antibiotics. We evaluated the medication history of patients undergoing IO to explore other medications that affect overall survival and to estimate the relative impact of each medication when given in combination. Methods: A retrospective review of patients with advanced cancer who received IO from 2011 to 2017 at the Ohio State University was performed with IRB approval. Data were extracted from the medical record, including medication history 180 days around the start of IO therapy. Data were collected in a REDCap database. Overall Survival (OS) was calculated from the initiation of IO. Cox Proportional-Hazards models were used and evaluated by log-rank test at alpha = 0.05. All calculations were performed using the survival and survminer packages in R. Results: Patients who received antibiotics or corticosteroids had decreased OS (p = 0.019 and p = 0.043, respectively) across several cancer types. Medications that were not significantly associated with OS included statins (p = 0.38), proton pump inhibitors (p = 0.94), H2 blockers (p = 0.27) and NSAIDS (p = 0.46). A total of 159 patients had complete data for all medications suitable for modeling relative effects. 149 (94%) of patients received antibiotics within 180 days of IO and 19 (12%) received both corticosteroids and antibiotics. The combination of corticosteroids and antibiotics had lower median OS than antibiotics alone or neither medication (p < 0.0018). A Cox Proportional Hazards model of antibiotics and corticosteroids, controlling for age, BMI and ECOG performance status, showed antibiotics, age and BMI to be significant predictors. Conclusions: Antibiotics and corticosteroids near the start of IO reduced overall survival, and the combination reduced the median overall survival further. However, a combined model that controlled for age, BMI and ECOG showed antibiotics, age and BMI to have a significant effect on OS. Though preliminary, these results suggest that antibiotics and corticosteroids may be affecting OS in the context of IO through overlapping pathways.

A precision medicine approach in sarcoma: identification of patients who may benefit from early use of pazopanib

Soft tissue sarcomas (STS) are a heterogeneous group of over 100 histologically and genetically distinct mesenchymal tumors. Standard of care for metastatic STS has historically relied on anthracycline-based chemotherapy regimens. Although effective for some patients, conventional chemotherapeutic agents used in STS are associated with substantial toxicity and also are not equally effective in all histologic subtypes of sarcoma. Pazopanib is an orally active antiangiogenic drug that is approved for non-adipogenic sarcomas after failure of at least one line of previous chemotherapy, and has a relatively favorable toxicity profile. Earlier use of pazopanib may be a better choice for patients with subtypes of sarcoma that do not respond well to conventional chemotherapy or those who are unlikely to tolerate chemotherapy. Here we review the evidence for the activity and toxicity profile of pazopanib and consider potential histologic, clinical, and genetic predictive factors that can help to guide treatment choices. Further prospective studies validating these observations may lead to refinement of a precision medicine approach to match ideal sarcoma patients to earlier treatment with pazopanib over traditional chemotherapy.

Cardio-Oncology: Cancer Therapy-related Cardiovascular Complications in a Molecular Targeted Era: New Concepts and Perspectives

Cardio-oncology is a medical discipline that identifies, prevents, and treats the cardiovascular complications related to cancer therapy. Due to the remarkable proliferation of new cancer therapies causing cardiovascular complications, such as hypertension, heart failure, vascular complications, and cardiac arrhythmia, we provide an extensive, comprehensive revision of the most up-to-date scientific information available on the cardiovascular complications associated with the use of newer, novel chemotherapeutic agents, including their reported incidence, suggested pathophysiology, clinical manifestations, potential treatment, and prevention. The authors consider this topic to be relevant for the clinicians since cardiovascular complications associated with the administration of recently approved drugs are relatively underappreciated. The purpose of this article is to provide a state-of-the-art review of cardiovascular complications associated with the use of newer, novel chemotherapeutic agents and targeted therapies, including their reported incidence, suggested pathophysiology, clinical manifestations, potential treatment, and prevention.  Ongoing efforts are needed to provide a better understanding of the frequency, mechanisms of disease, prevention, and treatment of cardiovascular complications induced by the newer, novel chemotherapeutic agents. Development of a cardio-oncology discipline is warranted in order to promote task forces aimed at the creation of oncology patient-centered guidelines for the detection, prevention, and treatment of potential cardiovascular side effects associated with newer cancer therapies.

Treatment with a Small Molecule Mutant IDH1 Inhibitor Suppresses Tumorigenic Activity and Decreases Production of the Oncometabolite 2-Hydroxyglutarate in Human Chondrosarcoma Cells

Chondrosarcomas are malignant bone tumors that produce cartilaginous matrix. Mutations in isocitrate dehydrogenase enzymes (IDH1/2) were recently described in several cancers including chondrosarcomas. The IDH1 inhibitor AGI-5198 abrogates the ability of mutant IDH1 to produce the oncometabolite D-2 hydroxyglutarate (D-2HG) in gliomas. We sought to determine if treatment with AGI-5198 would similarly inhibit tumorigenic activity and D-2HG production in IDH1-mutant human chondrosarcoma cells. Two human chondrosarcoma cell lines, JJ012 and HT1080 with endogenous IDH1 mutations and a human chondrocyte cell line C28 with wild type IDH1 were employed in our study. Mutation analysis of IDH was performed by PCR-based DNA sequencing, and D-2HG was detected using tandem mass spectrometry. We confirmed that JJ012 and HT1080 harbor IDH1 R132G and R132C mutation, respectively, while C28 has no mutation. D-2HG was detectable in cell pellets and media of JJ012 and HT1080 cells, as well as plasma and urine from an IDH-mutant chondrosarcoma patient, which decreased after tumor resection. AGI-5198 treatment decreased D-2HG levels in JJ012 and HT1080 cells in a dose-dependent manner, and dramatically inhibited colony formation and migration, interrupted cell cycling, and induced apoptosis. In conclusion, our study demonstrates anti-tumor activity of a mutant IDH1 inhibitor in human chondrosarcoma cell lines, and suggests that D-2HG is a potential biomarker for IDH mutations in chondrosarcoma cells. Thus, clinical trials of mutant IDH inhibitors are warranted for patients with IDH-mutant chondrosarcomas.