NTRK-rearranged spindle cell neoplasm: Initial observation of imaging appearance and clinicopathologic correlation

OBJECTIVE

To explore pre-treatment imaging findings of neurotrophic tyrosine receptor kinase (NTRK)-rearranged spindle cell neoplasm, an emerging group of molecularly defined soft tissue tumors and summarize the clinical course, including TRK inhibitor therapy response.

MATERIALS AND METHODS

This retrospective study included 8 women and 4 men with NTRK-rearranged spindle cell neoplasm (median age, 35.5 years, range, 0-66). Available pre-treatment MRI, CT, PET, and US imaging were reviewed. Tumor histology and the patients' clinical course were reviewed.

RESULTS

Primary tumors were located within the soft tissue, lungs, kidney, and breast with soft tissue being the most prevalent site (n = 6). Pre-treatment MRI (n = 4) revealed linear hypointense signal foci and contrast enhancement in all patients with hemorrhage in half of the tumors. A tail sign (n = 1) and fluid levels (n = 1) were less frequent. Ultrasound showed well-marginated hypoechoic masses with internal flow. Primary tumors were all non-calcified on CT (4/4). Metastases were FDG-avid (4/4). Among the 8 patients who developed metastasis, 7 developed pulmonary metastases. All four patients who received NTRK inhibitor therapy showed an initial decrease in tumor size or FDG uptake.

CONCLUSION

NTRK-rearranged neoplasms may occur as enhancing masses with linear hypointense signal foci on MRI and FDG avid metastases on PET. Pulmonary metastases were frequent in our study. Initial treatment response is observed in most patients.

GRM1-Rearranged Chondromyxoid Fibroma With FGF23 Expression: A Potential Pitfall in Small Biopsies

The clinical, radiological, and histopathological features of chondromyxoid fibroma can sometimes resemble those of other benign or malignant tumors. Recently, recurrent GRM1 rearrangements have been identified in chondromyxoid fibroma, and GRM1 positivity by immunohistochemistry has emerged as a dependable surrogate marker for this molecular alteration. Phosphaturic mesenchymal tumor is a rare tumor that often exhibits overexpression of fibroblastic growth factor 23 (FGF23) through various mechanisms. In this report, we present a case of GRM1-rearranged chondromyxoid fibroma that also exhibited FGF23 expression via in situ hybridization, posing significant diagnostic challenges during workup of the initial core biopsy. We hope that this case can serve as an educational resource, shedding light on a rare diagnostic pitfall.

Non-standard employment and COVID-19 testing in South Korean workers

OBJECTIVES

SARS-CoV-2 testing has been critical in monitoring and containing the COVID-19 pandemic, but there is a dearth of studies on how individuals' adherence to testing varies according to their working conditions. This study aimed to investigate the association between the type of employment contract and COVID-19 testing among wage workers in South Korea.

STUDY DESIGN

We used a nationally representative sample of employees aged 20-65 years collected from March 24 to 31, 2022. To focus on individual responses when the test was recommended, our sample consisted of 1266 participants who had experienced symptoms of COVID-19 or had been exposed to a confirmed case in the household.

METHODS

We used multivariate logistic regression to estimate the association between the odds of receiving a PCR test and the type of employment contract while controlling for other potential covariates.

RESULTS

The percentage of participants who had a SARS-CoV-2 PCR test was 77.8%. After adjusting for all potential covariates, daily workers (OR = 0.35, 95% CI 0.18 to 0.70, P = 0.003) and part-time workers (OR = 0.58, 95% CI 0.39 to 0.86, P = 0.007) had significantly lower odds of being tested relative to standard workers. Other temporary or atypical workers showed no significant differences from standard workers.

CONCLUSION

Our findings suggested that individuals in the most vulnerable job positions, with less job security and working hours, exhibited a decreased inclination to undergo COVID-19 testing. More effective job retention and income support policies are required to improve compliance.

Chordoma arising from the coccygeal disc and mimicking a pilonidal cyst

Chordomas are rare, low-grade malignant tumors often found in the sacrococcygeal region and prone to local recurrence. We report an atypical presentation of a 40-year-old patient with a symptomatic midline retrococcygeal lesion that was presumptively treated as a pilonidal cyst due to its clinical and imaging features. After surgical pathology rendered the diagnosis of chordoma, the patient required salvage surgery in the form of partial sacrectomy with soft tissue flap coverage. In addition to the unusually predominant retrococcygeal location, surgical pathology identified an intervertebral disc origin rather than the typical osseous origin. To our knowledge, this presentation of chordoma with coccygeal intervertebral origin and a large subcutaneous mass at imaging has rarely been reported in the literature. We describe this case to raise awareness of atypical presentations of sacrococcygeal chordoma that may lead to erroneous presumptive diagnosis and treatment.

Safety and efficacy of transitioning from selexipag to oral treprostinil in pulmonary arterial hypertension: Findings from the ADAPT registry

PURPOSE

Oral treprostinil and selexipag are drugs targeting the prostacyclin pathway and are approved for treatment of pulmonary arterial hypertension (PAH). In the setting of unsatisfactory clinical response or tolerability issues while on selexipag, there is little data on clinical benefit, safety, or strategies on transitioning to oral treprostinil. Using prospective data from the ADAPT registry, we aimed to evaluate clinical outcomes, safety, and transition strategies in ten patients with PAH transitioning from selexipag to oral treprostinil.

METHODS

ADAPT was a prospective, real-world, multicenter, United States-based registry of patients with PAH newly started on oral treprostinil, with a cohort of patients (n = 10) transitioning from selexipag to oral treprostinil. PAH variables of interest were collected from standard-of-care clinic visits. Clinical improvement was defined by modified REPLACE criterion, and risk was assessed by REVEAL Lite 2 from baseline to last follow-up. Real world transition strategies were recorded. Healthcare utilization or worsening PAH was evaluated within 30 days of transitions.

RESULTS

Seven patients transitioned due to worsening PAH or lack of efficacy on selexipag, and three patients transitioned due to tolerability issues. Based on the modified REPLACE criterion, five patients demonstrated clinical improvement after transition from selexipag to oral treprostinil. Using REVEAL Lite 2 to assess risk, three patients improved and five patients maintained risk category from baseline to last follow-up. All transitions occurred in an outpatient setting either as abrupt stop/start or cross-titration, without parenteral treprostinil bridging.

CONCLUSION

Transition from selexipag to oral treprostinil was safe, performed without parenteral prostacyclin bridging, and resulted in clinical and categorical risk improvements in some patients.

Giant-cell-poor giant cell tumor of bone: report of two cases and literature review

Giant cell tumor of bone (GCTB) is a locally aggressive tumor that shows predilection for the metaphysis/epiphysis of long bones, with an incidence of 4-5% of primary bone tumors. GCTB shows two main populations of cells: mononuclear cells and non-neoplastic multi-nucleated giant cells, with or without fibrous background. On the other hand, giant-cell-poor GCTB are rare with only few reports in the literature. These cases offer a diagnostic challenge, given the absence of giant cells and such cases have consistently been shown to harbor the H3F3A gene mutation by sequencing. The H3.3 G34W mutation-specific monoclonal antibody has shown high specificity in the diagnosis of GCTB. Two cases of giant-cell-poor GCTB are presented in this study, in which giant cells were absent or sparse and the diagnosis of GCTB was confirmed by the expression of H3.3 G34W monoclonal antibody in the mononuclear cells by immunohistochemistry. Whether this represents a histologic variant of GCTB or partial involution of GCTB is not yet fully understood; however, an immune response, infectious/inflammatory reaction, and/or anti-tumor cytokine production have been purported to be factors inciting disease regression in GCTB.

A Phase II Study of Epacadostat and Pembrolizumab in Patients with Advanced Sarcoma

PURPOSE

Epacadostat, an indole 2,3 dioxygenase 1 (IDO1) inhibitor, proposed to shift the tumor microenvironment toward an immune-stimulated state, showed early promise in melanoma but has not been studied in sarcoma. This study combined epacadostat with pembrolizumab, which has modest activity in select sarcoma subtypes.

PATIENTS AND METHODS

This phase II study enrolled patients with advanced sarcoma into five cohorts including (i) undifferentiated pleomorphic sarcoma (UPS)/myxofibrosarcoma, (ii) liposarcoma (LPS), (iii) leiomyosarcoma (LMS), (iv) vascular sarcoma, including angiosarcoma and epithelioid hemangioendothelioma (EHE), and (v) other subtypes. Patients received epacadostat 100 mg twice daily plus pembrolizumab at 200 mg/dose every 3 weeks. The primary endpoint was best objective response rate (ORR), defined as complete response (CR) and partial response (PR), at 24 weeks by RECIST v.1.1.

RESULTS

Thirty patients were enrolled [60% male; median age 54 years (range, 24-78)]. The best ORR at 24 weeks was 3.3% [PR, n = 1 (leiomyosarcoma); two-sided 95% CI, 0.1%-17.2%]. The median PFS was 7.6 weeks (two-sided 95% CI, 6.9-26.7). Treatment was well tolerated. Grade 3 treatment-related adverse events occurred in 23% (n = 7) of patients. In paired pre- and post-treatment tumor samples, no association was found between treatment and PD-L1 or IDO1 tumor expression or IDO-pathway-related gene expression by RNA sequencing. No significant changes in serum tryptophan or kynurenine levels were observed after baseline.

CONCLUSIONS

Combination epacadostat and pembrolizumab was well tolerated and showed limited antitumor activity in sarcoma. Correlative analyses suggested that inadequate IDO1 inhibition was achieved.

Risk factors for persistent pain after breast cancer surgery: a multicentre prospective cohort study

Identifying factors associated with persistent pain after breast cancer surgery may facilitate risk stratification and individualised management. Single-population studies have limited generalisability as socio-economic and genetic factors contribute to persistent pain development. Therefore, this prospective multicentre cohort study aimed to develop a predictive model from a sample of Asian and American women. We enrolled women undergoing elective breast cancer surgery at KK Women's and Children's Hospital and Duke University Medical Center. Pre-operative patient and clinical characteristics and EQ-5D-3L health status were recorded. Pain catastrophising scale; central sensitisation inventory; coping strategies questionnaire-revised; brief symptom inventory-18; perceived stress scale; mechanical temporal summation; and pressure-pain threshold assessments were performed. Persistent pain was defined as pain score ≥ 3 or pain affecting activities of daily living 4 months after surgery. Univariate associations were generated using generalised estimating equations. Enrolment site was forced into the multivariable model, and risk factors with p < 0.2 in univariate analyses were considered for backwards selection. Of 210 patients, 135 (64.3%) developed persistent pain. The multivariable model attained AUC = 0.807, with five independent associations: age (OR 0.85 95%CI 0.74-0.98 per 5 years); diabetes (OR 4.68, 95%CI 1.03-21.22); pre-operative pain score at sites other than the breast (OR 1.48, 95%CI 1.11-1.96); previous mastitis (OR 4.90, 95%CI 1.31-18.34); and perceived stress scale (OR 1.35, 95%CI 1.01-1.80 per 5 points), after adjusting for: enrolment site; pre-operative pain score at the breast; pre-operative overall pain score at rest; postoperative non-steroidal anti-inflammatory drug use; and pain catastrophising scale. Future research should validate this model and evaluate pre-emptive interventions to reduce persistent pain risk.

Bone Lesions Detected on Breast MRI: Clinical Outcomes and Features Associated with Metastatic Breast Cancer

Objective

To determine prevalence and frequency of malignancy among bone lesions detected on breast MRI and to identify clinical and imaging features associated with bone metastases from breast cancer (BC), as bone lesions are suboptimally evaluated on breast imaging protocols and can present a diagnostic challenge.

Methods

This IRB-approved retrospective review of breast MRIs performed from June 2009 to June 2018 identified patients with bone lesions. Demographic, clinical, and MRI features were reviewed. Clinical outcome of bone lesions was determined based on pathology and/or additional diagnostic imaging. All benign lesions had ≥ 2 years of imaging follow-up. Statistics were computed with Fisher's exact and Wilcoxon rank sum tests.

Results

Among all patients with breast MRI, 1.2% (340/29 461) had bone lesions. Of these, 224 were confirmed benign or metastatic BC by pathology or imaging follow-up, with 70.1% (157/224) be- nign and 29.9% (67/224) metastatic. Bone metastases were associated with BC history (P < 0.001), with metastases occurring in 58.2% (53/91) of patients with current BC, 17.9% (14/78) patients with prior BC, and 0.0% (0/55) without BC. Bone metastases were associated with invasive and ad- vanced stage BC and, on MRI, with location in sternum, ribs, or clavicles, larger size, multiplicity, andT1 hypointensity (all P < 0.01 in tests of overall association).

Conclusion

Of clinically confirmed breast MRI-detected bone lesions, 30% were bone metastases; all were detected in patients with current or prior BC. Metastases were associated with advanced stage, invasive carcinoma, larger lesion size, multiplicity, low T1 signal, and non-spine location.

Myxoid pleomorphic liposarcoma is distinguished from other liposarcomas by widespread loss of heterozygosity and significantly worse overall survival: a genomic and clinicopathologic study

Myxoid pleomorphic liposarcoma (MPLPS) is a recently described and extremely rare subtype of liposarcoma with a predilection for the mediastinum. However, the genomic features of MPLPS remain poorly understood. We performed comprehensive genomic profiling of MPLPS in comparison with pleomorphic liposarcoma (PLPS) and myxoid/round cell liposarcoma (MRLPS). Of the 8 patients with MPLPS, 5 were female and 3 were male, with a median age of 32 years old (range 10-68). All except one were located in the mediastinum, with invasion of surrounding anatomic structures, including chest wall, pleura, spine, and large vessels. All cases showed an admixture of morphologies reminiscent of PLPS and MRLPS, including myxoid areas with plexiform vasculature admixed with uni- and/or multivacuolated pleomorphic lipoblasts. Less common features included well-differentiated liposarcoma-like areas, and in one case fascicular spindle cell sarcoma reminiscent of dedifferentiated LPS. Clinically, 4 experienced local recurrence, 4 had distant metastases and 5 died of disease. Compared to PLPS and MRLPS, patients with MPLPS had worse overall and progression-free survival. Recurrent TP53 mutations were present in all 8 MPLPS cases. In contrast, in PLPS, which also showed recurrent TP53 mutations (83%), RB1 and ATRX losses were more common. MRLPS was highly enriched in TERT promoter mutations (88%) and PI3K/AKT pathway mutations. Copy number profiling in MPLPS revealed multiple chromosomal gains with recurrent amplifications of chromosomes 1, 19 and 21. Importantly, allele-specific copy number analysis revealed widespread loss of heterozygosity (80% of the genome on average) in MPLPS, but not in PLPS or MRLPS. Our findings revealed genome-wide loss of heterozygosity co-existing with TP53 mutations as a characteristic genomic signature distinct from other liposarcoma subtypes, which supports the current classification of MPLPS as a stand-alone pathologic entity. These results further expand the clinicopathologic features of MPLPS, including older age, extra-mediastinal sites, and a highly aggressive outcome.

Quantitating Diffusion Enhancement in Pore Hierarchies

A microporous continuum traversed by a set of mutually perpendicular channels is considered to be a model for a hierarchically porous system of the mesoporous zeolite type. Transient profiles of molecular uptake as determined by kinetic Monte Carlo (kMC) simulation are found to be in excellent agreement with the result attained by the application of the two-region model (the Kärger model) of molecular diffusion. In particular, it is found that, in the two limiting cases referred to as fast exchange and slow exchange, there exist two simple analytical expressions for the rate of molecular uptake and hence for the quantification of transport enhancement in comparison with the purely microporous adsorbent. In the general case, transport enhancement is simply recognized by the reciprocal addition of the expressions in the two limiting cases.

Pilot study of bempegaldesleukin in combination with nivolumab in patients with metastatic sarcoma

PD-1 blockade (nivolumab) efficacy remains modest for metastatic sarcoma. In this paper, we present an open-label, non-randomized, non-comparative pilot study of bempegaldesleukin, a CD122-preferential interleukin-2 pathway agonist, with nivolumab in refractory sarcoma at Memorial Sloan Kettering/MD Anderson Cancer Centers (NCT03282344). We report on the primary outcome of objective response rate (ORR) and secondary endpoints of toxicity, clinical benefit, progression-free survival, overall survival, and durations of response/treatment. In 84 patients in 9 histotype cohorts, all patients experienced ≥1 adverse event and treatment-related adverse event; 1 death was possibly treatment-related. ORR was highest in angiosarcoma (3/8) and undifferentiated pleomorphic sarcoma (2/10), meeting predefined endpoints. Results of our exploratory investigation of predictive biomarkers show: CD8 + T cell infiltrates and PD-1 expression correlate with improved ORR; upregulation of immune-related pathways correlate with improved efficacy; Hedgehog pathway expression correlate with resistance. Exploration of this combination in selected sarcomas, and of Hedgehog signaling as a predictive biomarker, warrants further study in larger cohorts.

Social Hypersensitivity in Bipolar Disorder: An ERP Study

Introduction

Bipolar Disorder (BD) is a disorder in which cognitive function is relatively preserved but social functioning is markedly impaired. Interestingly, studies on BD show that the patients have a strong desire for social rewards. Hypersensitivity to social rewards in BD has not yet been sufficiently examined through experimental methods, although recent studies have pointed out that their reward hypersensitivity is the cause of symptoms and dysfunction.

Objectives

The purpose of this study was to investigate whether patients with BD are hypersensitive to social rewards using the social value capture task.

Methods

Groups of 25 BD and healthy control (HC) each completed the social value attention capture task. This task consists of a practice phase in which associative learning of social rewards with specific stimuli occurs, and a test phase in which the stimuli associated with rewards appear as distractors during the participants performing a selective attention task. We also recorded event-related potential (ERP) in the practice phase in order to investigate BDs’ cortical activity for social reward.

Results

showed significantly decreased accuracy rate and increased reaction time in the high social reward-associated distractor trials of the test phase in the BD compared to the HC. As a result of analysis in ERP components, P3 amplitude for social reward was significantly greater in the BD than the HC.

Conclusions

BD patients exhibit behavioral and physiological hypersensitivity to social rewards that might contribute to social dysfunction.

Disclosure

No significant relationships.

Phase Ib Trial of the Combination of Imatinib and Binimetinib in Patients with Advanced Gastrointestinal Stromal Tumors

PURPOSE

This phase Ib trial was designed to evaluate the safety and early efficacy signal of the combination of imatinib and binimetinib in patients with imatinib-resistant advanced gastrointestinal stromal tumors (GISTs).

PATIENTS AND METHODS

This trial used a standard 3 + 3 design to determine the recommended phase II dose (RP2D). Additional patients were enrolled on an expansion cohort at the RP2D enriching for succinate dehydrogenase (SDH)-deficient GISTs to explore potential efficacy.

RESULTS

The trial enrolled nine patients in the dose-escalation cohort and 14 in the dose-expansion cohort including six with SDH-deficient GISTs. Imatinib 400 mg daily with binimetinib 45 mg twice daily was established as the RP2D. Dose-limiting toxicity (DLT) was asymptomatic grade 4 creatinine phosphokinase (CPK) elevation. The most common non-DLT grade 3/4 toxicity was asymptomatic CPK elevation (69.6%). Other common ≥grade 2 toxicities included peripheral edema (17.4%), acneiform rash (21.7%), anemia (30.4%), hypophosphatemia (39.1%), and aspartate aminotransferase (AST) increase (17.4%). Two serious adverse events occurred (grade 2 dropped head syndrome and grade 3 central retinal vein occlusion). No unexpected toxicities were observed. Limited clinical activity was observed in KIT-mutant GIST. For SDH-deficient GISTs, one of five had confirmed RECIST1.1 partial response (PR). The median progression-free survival (mPFS) in patients with SDH-deficient GIST was 45.1 months [95% confidence interval (CI), 15.8-not estimable (NE)]; the median overall survival (mOS) was not reached (95% CI, 31.6 months-NE). One patient with a refractory metastatic SDH-deficient GIST had an exceptional pathologic response and durable clinical benefit.

CONCLUSIONS

The combination of imatinib and binimetinib is safe with manageable toxicity and has encouraging activity in SDH-deficient but not imatinib-refractory KIT/PDGFRA-mutant GISTs. The observed clinical benefits provide a motivation for a larger trial of the combination strategy in SDH-deficient GISTs.

Phase II Trial of Imatinib Plus Binimetinib in Patients With Treatment-Naive Advanced Gastrointestinal Stromal Tumor

PURPOSE

Dual targeting of the gastrointestinal stromal tumor (GIST) lineage-specific master regulators, ETV1 and KIT, by MEK and KIT inhibitors were synergistic preclinically and may enhance clinical efficacy. This trial was designed to test the efficacy and safety of imatinib plus binimetinib in first-line treatment of GIST.

METHODS

In this trial (NCT01991379), treatment-naive adult patients with confirmed advanced GISTs received imatinib (400 mg once daily) plus binimetinib (30 mg twice daily), 28-day cycles. The primary end point was RECIST1.1 best objective response rate (ORR; complete response plus partial response [PR]). The study was designed to detect a 20% improvement in the ORR over imatinib alone (unacceptable rate of 45%; acceptable rate of 65%), using an exact binomial test, one-sided type I error of 0.08 and type II error of 0.1, and a planned sample size of 44 patients. Confirmed PR or complete response in > 24 patients are considered positive. Secondary end points included Choi and European Organisation for Research and Treatment of Cancer Response Rate, progression-free survival (PFS), overall survival (OS), pathologic responses, and toxicity.

RESULTS

Between September 15, 2014, and November 15, 2020, 29 of 42 evaluable patients with advanced GIST had confirmed RECIST1.1 PR. The best ORR was 69.0% (two-sided 95% CI, 52.9 to 82.4). Thirty-nine of 41 (95.1%) had Choi PR approximately 8 weeks. Median PFS was 29.9 months (95% CI, 24.2 to not estimable); median OS was not reached (95% CI, 50.4 to not estimable). Five of eight patients with locally advanced disease underwent surgery after treatment and achieved significant pathologic response (≥ 90% treatment effect). There were no unexpected toxicities. Grade 3 and 4 toxicity included asymptomatic creatinine phosphokinase elevation (79.1%), hypophosphatemia (14.0%), neutrophil decrease (9.3%), maculopapular rash (7.0%), and anemia (7.0%).

CONCLUSION

The study met the primary end point. The combination of imatinib and binimetinib is effective with manageable toxicity and warrants further evaluation in direct comparison with imatinib in frontline treatment of GIST.

Long term follow-up and patterns of response, progression and hyperprogression in patients after PD-1 blockade in advanced sarcoma

PURPOSE

PD-1 blockade can mediate objective responses in advanced sarcomas, but their durability has not been established and it is unclear if hyperprogressive disease (HPD) occurs in sarcomas treated with PD-1 inhibitors.

METHODS

We pooled patients who were treated prospectively with nivolumab or pembrolizumab as monotherapy or with bempegaldesleukin, epacadostat, ipilimumab or Talimogene laherparepvec. We did a new independent assessment for HPD and analyzed clinical, pathologic and genomic data from baseline tumor biopsies. Our primary endpoint was the incidence of HPD; secondary endpoints were clinical or genomic correlates of response or HPD.

RESULTS

We treated 134 patients with advanced sarcoma from 2015 - 2019. Twenty-one patients (16%) had a complete or partial response (CR/PR), and 30% of responses were durable for over 2 years. Forty-eight (36%) patients had stable disease (SD), 45 (34%) had progressive disease without HPD (PD) and 15 (11%) had HPD. Five patients (4%) were not evaluable for HPD. The sarcoma subtypes, sites of metastasis, clinical course, and genomic alterations in patients with PD and HPD were similar, except HPD tumors were smaller at baseline.

CONCLUSIONS

In patients with advanced sarcoma, PD-1 blockade can mediate durable responses. HPD occurs in sarcoma at an incidence that is similar to what has been reported in other solid tumors, but patients with HPD were clinically and biologically similar to those who had PD. Further research is required to establish whether HPD is a biologically distinct phenomenon and whether a theoretical risk of HPD should influence patient management.

Tunable asymmetric spin wave excitation and propagation in a magnetic system with two rectangular blocks

Asymmetric spin wave excitation and propagation are key properties to develop spin-based electronics, such as magnetic memory, spin information and logic devices. To date, such nonreciprocal effects cannot be manipulated in a system because of the geometrical magnetic configuration, while large values of asymmetry ratio are achieved. In this study, we suggest a new magnetic system with two blocks, in which the asymmetric intensity ratio can be changed between 0.276 and 1.43 by adjusting the excitation frequency between 7.8 GHz and 9.4 GHz. Because the two blocks have different widths, they have their own spin wave excitation frequency ranges. Indeed, the spin wave intensities in the two blocks, detected by the Brillouin light scattering spectrum, were observed to be frequency-dependent, yielding tuneable asymmetry ratio. Thus, this study provides a new path to enhance the application of spin waves in spin-based electronics.

A phase 1b study of avelumab plus DCC-3014, a potent and selective inhibitor of colony stimulating factor 1 receptor (CSF1R), in patients with advanced high-grade sarcoma

11549

Background: Select sarcomas are infiltrated with immunosuppressive myeloid cells. DCC-3014 is an inhibitor of the CSF1R kinase that decreases tumor infiltrating myeloid cells in preclinical models. We hypothesized that DCC-3014 combined with the anti-PDL1 inhibitor avelumab would be safe and tolerable, decrease immunosuppressive myeloid cells, and increase cytotoxic T cells. Methods: This investigator initiated, open label, single center, phase I study of DCC-3014 plus avelumab in patients (pts) with unresectable or metastatic sarcoma utilized a standard 3+3 dose escalation design. DCC-3014 was administered on days 1-3 (loading dose of 20, 30, or 50 mg) followed by oral daily maintenance (10, 14, or 20 mg) in 28-day cycles; 800 mg of IV avelumab was administered q2weeks. The primary endpoint was to determine the recommended phase 2 dose (RP2D). Secondary endpoints defined the adverse event (AE) profile and assessed clinical efficacy. Peripheral blood CD14+Lin-HLA-DRlo myeloid-derived suppressor cells (MDSCs) were measured by flow cytometry. Results: 13 pts were treated; median age was 61 (range 32 – 71), 8 were female, and median prior lines of therapy was 5 (range 2 – 10). Histologic subtypes included leiomyosarcoma (LMS, n = 7), undifferentiated pleomorphic sarcoma (2), dedifferentiated liposarcoma (LPS, 2), synovial sarcoma (1), and pleomorphic LPS (1). The Table lists treatment-related AEs (TRAEs) of any grade (G) occurring in ≥ 10% of pts and all G ≥ 3 TRAEs, sorted by frequency. All pts had at least 1 TRAE. Seven pts (54%) had a G ≥ 3 TRAE. Most TRAEs were either G ≤ 2 or expected on-target effects of CSF1R inhibition. 1 of 6 pts on the highest dose level had a dose limiting toxicity (G4 elevated AST with abdominal pain) that resolved with treatment cessation. The highest dose level was declared the RP2D. Best objective response by RECIST 1.1 was stable disease in 3 pts; 2 had LMS and were treated at the highest dose level. At baseline, the mean proportion of monocytes in peripheral blood samples with an MDSC phenotype was 12.2% (range 7.1 – 19.9). 5 of 7 pts with serial blood samples had decreased circulating MDSCs (mean decrease of 26.9% from baseline to last time point). Conclusions: DCC-3014 combined with avelumab was safe and tolerable. Study therapy decreased circulating MDSCs in select patients; T cell analyses will be reported. Study expansion at the RP2D is ongoing. Clinical trial information: NCT04242238. [Table: see text]

Imaging features and clinical course of undifferentiated round cell sarcomas with CIC-DUX4 and BCOR-CCNB3 translocations

OBJECTIVE

To describe the pre-treatment imaging features and clinical course of undifferentiated round cell sarcomas with CIC-DUX4 and BCOR-CCNB3 translocations.

MATERIALS AND METHODS

In this retrospective study, several pre-treatment imaging features (tumor location, size, enhancement pattern, necrosis, flow voids, calcification, and FDG avidity) and the clinical course of patients were evaluated.

RESULTS

In 12 patients with CIC-DUX4 sarcomas (median age, 24 years; range, 12-75), sarcomas were located in the soft tissue (n = 10), bone (n = 1), and lungs (n = 1). On MRI, all 10 CIC-DUX4 sarcomas presented as a large necrotic mass (mean size 6.7 cm, range 2.3-11.3) with 100% demonstrating contrast enhancement, 60% showing flow voids, and 20% demonstrating fluid-fluid levels. On PET, the mean SUVmax was 13.2 (range, 8.5-18.1). Among 12 patients with follow-up, 3 died within a year of diagnosis. The most common site of metastases was the lungs (5/12). In 5 patients with BCOR-CCNB3 sarcomas (median age, 14 years; range, 2-17), sarcomas were located in the spine (n = 2), femur (n = 1), tibia (n = 1), and pelvis (n = 1). On radiograph or CT, 2 were lytic, 3 were sclerotic. Soft tissue calcifications occurred in 40% of BCOR-CCNB3 sarcomas. On MRI, all 3 BCOR-CCNB3 tumors enhanced with 33% demonstrating flow voids and 66% exhibiting necrosis. On PET, the mean SUVmax was 6.3 (range 5.7-6.9).

CONCLUSION

CIC-DUX4 sarcomas often present as necrotic and hypermetabolic soft tissue masses while sarcomas with BCOR-CCNB3 translocations are vascular bone lesions with necrosis at imaging. CIC-DUX4 sarcomas are clinically more aggressive than BCOR-CCNB3 sarcomas.

Objective Response Rate Among Patients With Locally Advanced or Metastatic Sarcoma Treated With Talimogene Laherparepvec in Combination With Pembrolizumab: A Phase 2 Clinical Trial

Importance

Patients with advanced sarcoma have limited treatment options. Talimogene laherparepvec (T-VEC) has been shown to increase tumor-specific immune activation via augmenting antigen presentation and T-cell priming.

Objective

To examine whether T-VEC in combination with pembrolizumab is associated with increased tumor-infiltrating lymphocyte infiltration and programmed death-ligand 1 expression and thus with increased antitumor activity in patients with locally advanced or metastatic sarcoma.

Design, Setting, and Participants

This open-label, single-institution phase 2 interventional trial of T-VEC plus pembrolizumab enrolled 20 patients with locally advanced or metastatic sarcoma between March 16 and December 4, 2017, for whom at least 1 standard systemic therapy had failed. The median duration of therapy was 16 weeks (range, 7-67 weeks). Reported analyses include data through December 14, 2018.

Intervention

Patients received pembrolizumab (200-mg flat dose) intravenously and T-VEC (first dose, ≤4 mL × 106 plaque-forming units [PFU]/mL; second and subsequent doses, ≤4 mL × 108 PFU/mL) injected into palpable tumor site(s) on day 1 of each 21-day cycle.

Main Outcomes and Measures

The primary end point was objective response rate (ORR; complete response and partial response) at 24 weeks determined by Response Evaluation Criteria In Solid Tumors (RECIST), version 1.1, criteria. Secondary end points included best ORR by immune-related RECIST criteria, progression-free survival rate at 24 weeks, overall survival, and safety.

Results

All 20 patients (12 women [60%]; median age, 63.5 years [range, 24-90 years]) were evaluable for response. The study met its primary end point of evaluating the best ORR at 24 weeks determined by RECIST, version 1.1, criteria; the best ORR was 30% (95% CI, 12%-54%; n = 6). The ORR overall was 35% (95% CI, 15%-59%; n = 7). The incidence of grade 3 treatment-related adverse events was low (4 patients [20%]). There were no grade 4 treatment-related adverse events or treatment-related deaths.

Conclusions and Relevance

In this phase 2 clinical trial, treatment with T-VEC plus pembrolizumab was associated with antitumor activity in advanced sarcoma across a range of sarcoma histologic subtypes, with a manageable safety profile. This combination therapy met its predefined primary study end point; further evaluation of T-VEC in combination with pembrolizumab for patients with select sarcoma subtypes is planned.

Trial Registration

ClinicalTrials.gov identifier: NCT03069378.

Single-Center Experience of Living Donor Liver Transplantation for Patients With Secondary Biliary Cirrhosis

BACKGROUND

Secondary biliary cirrhosis (SBC) represents a unique form of cirrhosis that develops in the liver secondary to persistent biliary obstruction. This study aimed to review the living donor liver transplants (LDLTs) performed at our center for patients with SBC and end-stage liver disease and to share the perioperative strategies undertaken to achieve satisfactory outcomes.

METHODS

The medical records of 29 patients who underwent LDLT for SBC between December 1994 and July 2018 at the Asan Medical Center (Seoul, South Korea) were retrospectively reviewed. Their clinical data were extracted and statistically analyzed. Survival curves were computed.

RESULTS

The perioperative and in-hospital morbidity rates were 72.4% and 10.3%, respectively. The overall mean recipient follow-up was 80.0 (SD, 66.4) months (range, 0.8-246.8 months). Patient survival rates after 1, 3, 5, and 10 years after transplant were 82.8%, 79.3%, 79.3%, and 79.3%, respectively. For liver grafts, the survival rates were 82.8%, 75.8%, 75.8%, and 75.8% at 1, 3, 5, and 10 years, respectively.

CONCLUSIONS

LDLT is potentially a final lifesaving resort for patients with SBC with portal hypertension. However, considering the difficulty of surgery and perioperative management, LDLT should be performed by experienced transplant surgeons in a center where a multidisciplinary approach is possible.

Impact of Magnetic Resonance Imaging (MRI) Findings on Management of Symptomatic Patients Following Radiofrequency Ablation (RFA) of Osteoid Osteoma (OO)

Object

To assess the impact of MRI findings on management of symptomatic patients following RFA of OO.

Materials & Methods

Retrospective review of 43 patients with RFA for OO between June 2010 and June 2017 was performed. Patient, nidus and ablation data were reviewed. Pre- and 6-8 weeks post-procedural MRI (n=32) were compared for coverage of nidus by ablation zone, bone marrow edema, nidus hyperintensity and other findings. Baseline pain levels and analgesic use were compared with post-procedural follow-up visit at 6-8 weeks. Three groups of clinical and MRI outcomes of complete (CR), partial (PR) and no response (NR) were defined. A weighted-kappa statistic was used to assess for agreement.

Results

Clinical responses were CR in 34/43 (79.1%, 95%CI: 64.0-90.0%), PR in 8/43 (18.6%) and NR in 1/43 (2.3%) patients. All 19/32 patients with MRI CR experienced clinical CR. One patient with MRI NR had clinical NR. All 7/32 patients with clinical PR had MRI PR. All 4/43 complications were in MRI PR or NR groups. Substantial agreement was observed between MRI and clinical outcomes (kappa:0.69, 95%CI:0.45-0.95). MRI helped determine etiologies in all symptomatic patients and their management (n=8).

Conclusions

MRI is recommended for symptomatic patients after ablation.

Myositis ossificans-like soft tissue aneurysmal bone cyst: a clinical, radiological, and pathological study of seven cases with COL1A1-USP6 fusion and a novel ANGPTL2-USP6 fusion

Herein we described the clinical, radiological, histological, and molecular characteristics of seven soft tissue aneurysmal bone cysts (STABCs) diagnosed and managed at a tertiary cancer center and to elucidate their relationship with myositis ossificans (MO). All cases had established imaging and histopathological diagnosis of STABC and were subject to fluorescence in situ hybridization (FISH) for USP6 rearrangement and Archer® FusionPlex® targeted RNA sequencing (RNASeq) analysis to identify the fusion partner. A thorough literature review of STABC and MO was conducted. The patients presented with painful masses unpreceded by trauma, occurring most commonly in the deep soft tissue of the thigh/gluteus (4/7), and also in the supraclavicular region, the axilla, and the hand. On imaging, the lesions were frequently associated with peripheral calcification on conventional radiographs and CT (6/7), cystic components on ultrasound, as well as perilesional edema (7/7) and fluid levels (3/7) on MRI. Bone scan (1/1) showed intense radiotracer uptake. Histologically, 6/7 cases demonstrated zonal arrangements reminiscent of MO. USP6 rearrangement was found in all seven cases by FISH and/or RNASeq. RNASeq further detected COL1A1-USP6 fusion in six cases and a novel ANGPTL2-USP6 fusion in one case. Four patients underwent resection of the tumors and were disease free at their last follow-up. Three patients who underwent incisional or needle biopsies had no evidence of disease progression on imaging studies. In conclusion, the clinical, radiological, and pathological overlap between STABC and MO suggests that they are closely related entities. A novel fusion ANGPTL2-USP6 is associated with distinct clinical and pathological presentation.

Association of immune-related adverse events (irAEs) with improved clinical outcome in sarcoma patients treated with immune checkpoint blockade (ICB)

11510

Background: IrAEs are associated with improved clinical outcomes after treatment with ICB in select epithelial malignancies. We hypothesized that sarcoma patients (pts) treated with ICB who developed an irAE would have improved outcomes compared to pts who had no irAE. Methods: Adverse events (AEs) from 3 sarcoma-specific ICB trials (nivolumab plus NKTR-214, pembrolizumab plus epacadostat, and pembrolizumab plus T-VEC) were reviewed. AEs probably or definitely related to ICB were classified as immune- or non-immune-related by the principal investigator. Endpoints of interest included best overall response (BOR) by RECIST 1.1 (complete response [CR]/partial response [PR]), durable clinical benefit (DCB; CR/PR/stable disease [SD] ≥ 16 weeks), and progression-free survival (PFS). Outcomes were stratified by the presence or absence of ≥ 1 irAE of any grade and by grade 1-2, grade 3-4, or no irAE (three-category comparison). Results: A total of 124 pts received ICB on these studies. Median pt age was 56 (range: 13-90); 53% were male; all but one pt had a performance status of ≤ 1. BOR was PR in 12 pts, SD in 41, and PD in 69. 2 pts were not evaluable. 40 pts (32%) had ≥ 1 irAE of any grade, 6 of whom had a grade 3-4 irAE. The most common irAEs (≥ 5% of pts) were rash (15%), arthralgia (11%), myalgia (9%), pruritis (8%), and hypothyroidism (6%). The proportion of pts with a CR/PR was higher in pts with than without an irAE (18% vs. 6%, respectively; P = 0.058). A significantly higher proportion of pts with an irAE had DCB compared to those without (53% and 29%, respectively; P = 0.017). The median PFS of pts with an irAE was 16.6 months compared to 10.6 in those without (P = 0.013). The proportion of pts with a grade 3-4 irAE and a CR/PR was highest (33%) compared to pts with grade 1-2 (15%) or no irAE (6%) (P = 0.048). More pts with grade 3-4 irAE achieved DCB (67%) than grade 1-2 (50%) or no irAE (29%) (P = 0.027). Median PFS was 22.6, 15, and 10.6 weeks in the grade 3-4, grade 1-2, and no irAE groups, respectively (P = 0.047). Conclusions: Approximately one-third of advanced sarcoma pts with ICB-based immunotherapy developed an irAE. As reported previously in select carcinomas, sarcoma pts with irAEs were more likely to have clinical benefit than those without irAEs. Further research is needed to understand the mechanism behind this association and to validate these findings prospectively.

A phase II study of MEK162 (binimetinib [BINI]) in combination with imatinib in patients with untreated advanced gastrointestinal stromal tumor (GIST)

11508

Background: ETV1 and KIT are lineage-specific master transcriptional and signaling survival factors in GIST. In preclinical models, dual lineage targeting of ETV1 by MEK inhibition with BINI and KIT by imatinib are synergistic in suppressing GIST tumorigenesis and progression. This single-arm phase II study is designed to test the efficacy of the BINI+imatinib as a first-line treatment in patients (pts) with advanced GIST. Methods: Adult pts with untreated advanced GIST received imatinib (400mg daily) plus BINI (30mg twice daily), 28-day cycles. The primary endpoint (EP) was RECIST1.1 objective response rate (ORR) (complete response [CR]+partial response [PR]). The study was designed to detect a 20% improvement in the ORR of imatinib alone (unacceptable rate of 45%; acceptable rate of 65%). A sample size of 44 patients was required, using an exact binomial test, one-sided type I error of 0.08 and type II error of 0.1. Confirmed PR in > 24 pts would be considered positive. Secondary EPs included RR by Choi and EORTC criteria, resectability conversion rate (RCR), progression free survival (PFS), overall survival (OS) and long-term AEs. Correlatives included characterization of tumor genomics by MSK-IMPACT, cfDNA by MSK-ACCESS, ETV1 protein levels and transcriptomes and signaling inhibition. Results: At data cutoff of Jan 31, 2020, 38/39 pts with advanced GIST of all genotypes, including 3 KIT/PDGFRA-wild type GIST pts, were evaluable for primary EP. Median age 60 (range 29-78), 29% female. 26/38 pts with confirmed PR; Best ORR was 68.4% (two-sided 95% CI, 51-83%; one-sided 90% CI, 57-100%). 8/9 pts became resectable after treatment; RCR was 88.9% (95% CI, 52-100%). 13 pts remain on trial (2-159 weeks [wks]). 9 pts discontinued trial due to disease progression (11-159 wks); one pt progressed within 3 months, indicating primary resistance. Grade 3/4 toxicity included CPK elevation (asymptomatic, 61%), neutrophil decrease (11%), maculopapular rash (8%), anemia (8%). No unexpected toxicities observed. Correlation of outcome with MSK-IMPACT, MSK-Access and paired tumor biopsies will be presented. Conclusions: This study met its primary endpoint. BINI plus imatinib is highly effective in treatment-naive advanced GIST, with expected and manageable long-term treatment-associated toxicities. The combination strategy warrants further evaluation in direct comparison with imatinib in the frontline treatment of GIST. Clinical trial information: NCT01991379 .

MRI Patterns of Extrapontine Lesion Extension in Diffuse Intrinsic Pontine Gliomas

BACKGROUND AND PURPOSE

Diffuse intrinsic pontine glioma is a devastating childhood cancer that despite being primarily diagnosed by MR imaging alone, lacks robust prognostic imaging features. This study investigated patterns and quantification of extrapontine lesion extensions as potential prognostic imaging biomarkers for survival in children with newly diagnosed diffuse intrinsic pontine glioma.

MATERIALS AND METHODS

Volumetric analysis of baseline MR imaging studies was completed in 131 patients with radiographically defined typical diffuse intrinsic pontine gliomas. Extrapontine tumor extension was classified according to the direction of extension: midbrain, medulla oblongata, and right and left middle cerebellar peduncles; various extrapontine lesion extension patterns were evaluated. The Kaplan-Meier method was used to estimate survival differences; linear regression was used to evaluate clinical-radiographic variables prognostic of survival.

RESULTS

At least 1 extrapontine lesion extension was observed in 125 patients (95.4%). Of the 11 different extrapontine lesion extension patterns encountered in our cohort, 2 were statistically significant predictors of survival. Any extension into the middle cerebellar peduncles was prognostic of shorter overall survival (P = .01), but extension into both the midbrain and medulla oblongata but without extension into either middle cerebellar peduncle was prognostic of longer overall survival compared with those having no extension (P = .04) or those having any other pattern of extension (P < .001).

CONCLUSIONS

Within this large cohort of patients with typical diffuse intrinsic pontine gliomas, 2 specific extrapontine lesion extension patterns were associated with a significant overall survival advantage or disadvantage. Our findings may be valuable for risk stratification and radiation therapy planning in future clinical trials.

Technical and nidus-specific factors associated with adequacy of intraprocedural biopsy samples preceding radiofrequency ablation of osteoid osteoma

PURPOSE

To examine the diagnostic yield of intraprocedural percutaneous biopsy performed at the time of radiofrequency ablation of suspected Osteoid Osteoma (OO) and identify technical and nidus-specific factors associated with diagnostic adequacy.

MATERIALS AND METHODS

Following IRB approval, a total of 42 patients (male: 28, female: 14; mean age: 29 years) who underwent intraprocedural biopsy immediately prior to RFA between June 2010 and June 2017 were retrospectively identified. The nidi were located in various locations. The nidi had a mean size of 6.3 mm (range: 3-11 mm, Standard deviation (SD): 2.26). Core biopsies were performed by one of 15 operators. Biopsies were performed with two needle types ranging from 11-G to 15-G with a mean number of samples of 1.8 (range: 1-5, SD: 1.01). Electronic records and imaging were reviewed for demographics, nidus characteristics, biopsy details and diagnostic yield. Multivariate logistic regression of nidus-specific and biopsy-specific factors was performed.

RESULTS

A total of 22/42 (52.3%) of the biopsies were adequate for histological diagnosis of OO. For the two experienced operators, the diagnostic yield was 67% (6/9) and 80% (8/10). Biopsy adequacy was significantly correlated with presence of an osteoid matrix (p = 0.03), obtaining >1 core sample (p = 0.03), the needle track passing through the nidus (p = 0.0003) and thinner (2.5 mm) intraprocedural CT slices (p = 0.03). On multivariate analysis, use of thinner intraprocedural CT slices was found to be associated with adequate biopsy (p = 0.02).

CONCLUSION

Intraprocedural percutaneous biopsy samples of nidi highly-suspected to be OO at the time of RFA were diagnostic in 52% of patients. Multivariate analysis shows thinner intraprocedural CT slices to be a significantly associated with biopsy adequacy.

Comparative identification, nutritional, and physiological regulation of chicken liver-enriched genes

The liver performs a number of vital functions in the chicken. In order to identify unique gene expression patterns and link them to potential functions in the chicken liver, genes enriched in the liver of chickens needed to be investigated in a comparative manner. In this study, 41 liver-enriched genes were identified through chicken microarray, and many of them were validated through comparative analysis of mice and humans. Thirteen of them were unique in chickens, and their liver enhancement was confirmed by reverse transcription PCR. Furthermore, the expression of those 13 chicken liver-enriched genes was investigated, in response to nutritional and physiological challenges. Real-time PCR revealed that expression of PIT54 (P < 0.01), phosphoribosyl pyrophosphate synthetase 2 (PRPS2) (P < 0.05), sulfotransferase (SULT) (P < 0.05), and cytochrome P450 family 2 subfamily C, polypeptide 18 (CYP2C18) (P < 0.05) were significantly decreased in the liver during fasting compared to ad libitum control. During the post-laying stage, expression of GAL8 was significantly increased (P < 0.01), but CYP2C18 expression was significantly reduced (P < 0.05). Liver-enriched genes that were identified in this study and their expression patterns under fasting and the post-laying stage will serve as future targets to gain a better understanding of liver physiology, function and development in poultry.

A Phase I Study of Binimetinib (MEK162) Combined with Pexidartinib (PLX3397) in Patients with Advanced Gastrointestinal Stromal Tumor

Lessons Learned.

The combination of pexidartinib and binimetinib was safe and tolerable and demonstrated encouraging signs of efficacy in two patients with advanced gastrointestinal stromal tumor (GIST) refractory to tyrosine kinase inhibitors (TKIs).

Molecular profiling of GISTs at diagnosis and upon progression may provide insight into the mechanisms of response or resistance to targeted therapies.

Additional trials are needed to further explore combined KIT and MEK inhibition in treatment‐naïve and TKI‐refractory patients with advanced GIST.

Background.

Nearly all patients with advanced gastrointestinal stromal tumor (GIST) develop resistance to imatinib, and subsequent treatments have limited efficacy. Dual inhibition of KIT and MAPK pathways has synergistic antitumor activity in preclinical GIST models.

Methods.

This was an investigator‐initiated, phase I, dose escalation study of the MEK inhibitor binimetinib combined with pexidartinib, a potent inhibitor of CSF1R, KIT, and FLT3, in patients with advanced or metastatic GIST who progressed on imatinib. The primary endpoint was phase II dose determination; secondary endpoints included safety, tolerability, and efficacy. An expansion cohort to further evaluate safety and efficacy was planned.

Results.

Two patients were treated at dose level one (binimetinib 30 mg b.i.d. and pexidartinib 400 mg every morning and 200 mg every evening), after which the study was terminated by the manufacturer. No dose‐limiting toxicities (DLTs) were reported, and treatment was well tolerated. The only grade ≥3 treatment‐emergent adverse event (TEAE) was asymptomatic elevated creatine phosphokinase (CPK). Both patients had a best response of stable disease (SD) by RECIST. Progression‐free survival (PFS) and overall survival (OS) were 6.1 and 14.6 months, respectively, in one patient with five prior lines of therapy. The second patient with NF1‐mutant GIST had a 27% decrease in tumor burden by RECIST and remains on study after 19 months of treatment.

Conclusion.

Pexidartinib combined with binimetinib was tolerable, and meaningful clinical activity was observed in two imatinib‐refractory patients.

Pilot study of NKTR214 and nivolumab in patients with sarcomas

11010

Background: Monotherapy checkpoint inhibitors have minimal efficacy in most patients with metastatic sarcoma. NKTR-214 is a CD122-preferential IL-2 pathway agonist that activates and expands natural killer and CD8+ T cells. Phase I/II data demonstrated the safety and efficacy of nivolumab plus NKTR-214 in multiple tumor types. A trial of NKTR-214 plus nivolumab was initiated in patients with selected sarcomas. Methods: This is a multi-center pilot study enrolling patients (pts) failing prior regimens within 9 cohorts: leiomyosarcoma (LMS), undifferentiated pleomorphic sarcoma (UPS), dedifferentiated liposarcoma (DDLPS), chondrosarcoma (CS), osteosarcoma (OS), angiosarcoma (AS), alveolar soft part sarcoma (ASPS), synovial sarcoma/small blue round cell and other. Pts received NKTR 0.006mg/kg with nivolumab 360 mg every 3 weeks. Primary endpoint was objective response rate (ORR), secondary endpoints were adverse events (AEs), progression-free, overall survival (PFS,OS) and clinical benefit rate (CBR.) Pre/on treatment biopsies performed on patients for correlative studies including PD-L1 expression and TIL characterization by immunohistochemistry, whole exome sequencing and RNAseq. Results: Enrollment completed with 10 patients in cohorts below. 50 pts enrolled (median age 58, range 14-80), 54% female. Median follow-up time is 13m. 50% of patients were refractory ≥3 lines of therapy. Grade 3/4 treatment related adverse events occurred in 26% of patients. 2% of patients stopped due to AEs. Median time to response was 3.6m. Responses seen in LMS, UPS, dedifferentiated CS; on-going in UPS/CS. Prolonged disease stability in DDLPS. 6 patients remain on treatment. Conclusions: Nivolumab plus NKTR-214 was safe and tolerable in heavily pre-treated and refractory sarcoma patients. Responses were protracted overtime; on-going in UPS and dedifferentiated CS. Prolonged disease stability seen in DDLPS in patients. All correlative analyses are in progress and will be presented. Enrollment continues with plans to add a treatment naïve cohort. Clinical trial information: NCT03282344. [Table: see text]

A phase II study of epacadostat and pembrolizumab in patients with advanced sarcoma

11049

Background: Tumors express IDO1, an intracellular enzyme involved in the degradation of tryptophan to kynurenine, in order to evade immunosurveillance. Epacadostat inhibits IDO1 and shifts the tumor microenvironment from an immunosuppressive state to an immune-stimulated state. Pembrolizumab previously demonstrated activity in select sarcoma subtypes. We performed an open-label, single-center, phase II study of epacadostat and pembrolizumab in patients with advanced sarcoma. Methods: Patients received the recommended phase II dose of oral epacadostat (100mg) twice per day and intravenous pembrolizumab (200mg/dose) every 3 weeks. The primary endpoint was best objective response rate (ORR) (complete response and partial response [PR]) at 24 weeks by RECIST 1.1. Secondary endpoints included adverse events (AEs), ORR by irRECIST, progression free survival (PFS) and overall survival (OS). Correlative studies performed on pre/on-treatment biopsy specimens included PD-L1, IDO1, and kynurenine expression and characterization of tumor infiltrating lymphocytes by IHC, whole exome and RNA sequencing. Results: Twenty-nine patients were enrolled [median age 53 years (range, 24-78), 57% male, ECOG PS 0 83%]. Histological subtypes included leiomyosarcoma (17%), UPS (17%), myxofibrosarcoma (7%), liposarcoma (10.5%), EHE (10.5%), angiosarcoma (3%), “other” sarcoma subtype (35%). Patients were refractory to 0 (21%), 1 (38%), 2 (24%) and ≥ 3 (17%) prior lines of therapy. The most common ( > 20% of pts) grade (G)1 or 2 treatment related AEs (TRAEs) observed included fatigue (31%), rash (31%) and ALT elevation (24%). G3 TRAEs included AST elevation (10%), ALT elevation, anemia, hypophosphatemia and increased lipase each occurred in 3% of pts. Three patients discontinued therapy due to G3 immune mediated hepatitis. Among the 29 evaluable patients 1 (3%) confirmed PR (leiomyosarcoma), 13 stable diseases (45%) and 15 progressions (52%) were observed by RECIST 1.1. The median PFS was 8.0 weeks (two-sided 95% CI: 6.9 ~ 26.7) and the PFS rate at 24 weeks was 27.9% (two-sided 95% CI: 15.0% ~ 52.2%). The median OS was not estimable (two-sided 95% CI: 40.9 weeks ~ NE). The OS at 24 weeks was 85.2% (95% CI: 72.8%, 99.7%). Conclusions: Epacadostat in combination with pembrolizumab was generally well tolerated. Limited anti-tumor activity was observed among advanced sarcoma patients. Correlative analyses including determination of adequacy of IDO1 inhibition will be reported. Clinical trial information: NCT03414229.

Plexiform fibrohistiocytic tumor: imaging features and clinical findings

OBJECTIVE

To describe the imaging features of plexiform fibrohistiocytic tumor and its associated clinical findings.

MATERIALS AND METHODS

An institutional database was searched to identify all patients with a pathological diagnosis of plexiform fibrohistiocytic tumor. The electronic medical record was reviewed for relevant clinical data. Radiologic images of the primary tumor site were reviewed by two radiologists to assess primary, residual, or recurrent tumor with respect to tumor location, size, morphology, MR signal characteristics and enhancement, and involvement of adjacent structures.

RESULTS

Thirteen patients with imaging of the primary tumor site were identified [eight female, five male; mean age, 15.9 years (range, 3-41 years)]. Plexiform fibrohistiocytic tumor typically manifested as a solitary, painless, firm, slow-growing lesion centered in the subcutaneous tissues, with a predilection for the upper extremity or head and neck region. Most tumors had a purely plaque-like or infiltrative morphology at MRI; some demonstrated no round or oval mass. Tumors were predominantly isointense to muscle on T1-weighted imaging and hyperintense on fluid-sensitive imaging, and enhanced after gadolinium contrast administration. Five patients (38%) had residual tumor after initial surgery, resembling postoperative changes. No patient had recurrent tumor. One patient (8%) developed metastases to local lymph nodes and to the lung. No patient died from plexiform fibrohistiocytic tumor.

CONCLUSIONS

Plexiform fibrohistiocytic tumor often manifests as a plaque-like or infiltrative process, sometimes without a round or oval mass, most commonly in the subcutaneous tissues of the upper extremity or head and neck region. Residual tumor is often present after initial surgery, and may be indistinguishable from postoperative changes.