Immune-related Adverse Events after Immune Checkpoint Blockade-based Therapy Are Associated with Improved Survival in Advanced Sarcomas.

The association between immune-related AEs (irAE) and outcome in patients with sarcoma is not known. We retrospectively reviewed a cohort of patients with advanced sarcoma treated with immune checkpoint blockade (ICB)-based therapy. Association of irAEs with survival was assessed using a Cox regression model that incorporated irAE occurrence as a time-dependent covariate. Tumor samples with available RNA sequencing data were stratified by presence of an irAE to identify patterns of differential gene expression. A total of 131 patients were included. Forty-two (32%) had at least one irAE of any grade and 16 (12%) had at least one grade ≥ 3 irAE. The most common irAEs were hypothyroidism (8.3%), arthralgias (5.3%), pneumonitis (4.6%), allergic reaction (3.8%), and elevated transaminases (3.8%). Median progression-free survival (PFS) and overall survival (OS) from the time of study entry were 11.4 [95% confidence interval (CI), 10.7-15.0) and 74.6 weeks (CI, 44.9-89.7), respectively. On Cox analysis adjusting for clinical covariates that were significant in the univariate setting, the HR for an irAE (HR, 0.662; CI, 0.421-1.041) approached, but did not reach statistical significance for PFS (P = 0.074). Patients had a significantly lower HR for OS (HR, 0.443; CI, 0.246-0.798; P = 0.007) compared with those without or before an irAE. Gene expression profiling on baseline tumor samples found that patients who had an irAE had higher numbers of tumor-infiltrating dendritic cells, CD8+ T cells, and regulatory T cells as well as upregulation of immune and inflammatory pathways. SIGNIFICANCE: irAE after ICB therapy was associated with an improved OS; it also approached statistical significance for improved PFS. Patients who had an irAE were more likely to have an inflamed tumor microenvironment at baseline.

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.

Identified Enrollment Challenges of Adolescent and Young Adult Patients on the Nonchemotherapy Arm of Children's Oncology Group Study ARST1321.

ARST1321, a trial of patients with advanced soft tissue sarcoma, was the first National Clinical Trials Network study codeveloped by pediatric and adult consortia with two treatment cohorts. We report on the findings of a survey to identify barriers to enrolling adolescent and young adult patients (15-39 years) onto the nonchemotherapy arm. The survey response rate was 31% with a 70% completion rate. Common identified reasons for low accrual in order of decreasing frequency included insufficient funding, lack of study awareness or interest, competing trials, toxicity concerns, philosophical differences in the therapy backbone, and regulatory and infrastructure barriers. Clinical Trials.gov ID: NCT02180867.

Long-term Follow-up and Patterns of Response, Progression, and Hyperprogression in Patients after PD-1 Blockade in Advanced Sarcoma.

PURPOSE: Programmed cell death protein 1 (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. EXPERIMENTAL DESIGN: 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 to 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.

Comprehensive Molecular Profiling of Desmoplastic Small Round Cell Tumor.

Desmoplastic small round cell tumor (DSRCT) is characterized by the EWSR1-WT1 t(11;22) (p13:q12) translocation. Few additional putative drivers have been identified, and research has suffered from a lack of model systems. Next-generation sequencing (NGS) data from 68 matched tumor-normal samples, whole-genome sequencing data from 10 samples, transcriptomic and affymetrix array data, and a bank of DSRCT patient-derived xenograft (PDX) are presented. EWSR1-WT1 fusions were noted to be simple, balanced events. Recurrent mutations were uncommon, but were noted in TERT (3%), ARID1A (6%), HRAS (5%), and TP53 (3%), and recurrent loss of heterozygosity (LOH) at 11p, 11q, and 16q was identified in 18%, 22%, and 34% of samples, respectively. Comparison of tumor-normal matched versus unmatched analysis suggests overcalling of somatic mutations in prior publications of DSRCT NGS data. Alterations in fibroblast growth factor receptor 4 (FGFR4) were identified in 5 of 68 (7%) of tumor samples, whereas differential overexpression of FGFR4 was confirmed orthogonally using 2 platforms. PDX models harbored the pathognomic EWSR1-WT1 fusion and were highly representative of corresponding tumors. Our analyses confirm DSRCT as a genomically quiet cancer defined by the balanced translocation, t(11;22)(p13:q12), characterized by a paucity of secondary mutations but a significant number of copy number alterations. Against this genomically quiet background, recurrent activating alterations of FGFR4 stood out, and suggest that this receptor tyrosine kinase, also noted to be highly expressed in DSRCT, should be further investigated. Future studies of DSRCT biology and preclinical therapeutic strategies should benefit from the PDX models characterized in this study. IMPLICATIONS: These data describe the general quiescence of the desmoplastic small round cell tumor (DSRCT) genome, present the first available bank of DSRCT model systems, and nominate FGFR4 as a key receptor tyrosine kinase in DSRCT, based on high expression, recurrent amplification, and recurrent activating mutations.

A phase II study of temsirolimus and liposomal doxorubicin for patients with recurrent and refractory bone and soft tissue sarcomas.

BACKGROUND: Relapsed and refractory sarcomas continue to have poor survival rates. The cancer stem cell (CSC) theory provides a tractable explanation for the observation that recurrences occur despite dramatic responses to upfront chemotherapy. Preclinical studies demonstrated that inhibition of the mechanistic target of rapamycin (mTOR) sensitizes the CSC population to chemotherapy. METHODS: Here we present the results of the Phase II portion of a Phase I/II clinical trial that aimed to overcome the chemoresistance of sarcoma CSC by combining the mTOR inhibitor temsirolimus (20 mg/m2 weekly) with the chemotherapeutic agent liposomal doxorubicin (30 mg/m2 monthly). RESULTS: Fifteen patients with relapsed/refractory sarcoma were evaluable at this recommended Phase 2 dose level. The median progression free survival was 315 days (range 27-799). Response rate, defined as stable disease or better for 60 days, was 53%. Nine of the patients had been previously treated with doxorubicin. Therapy was well tolerated. In a small number of patients, pre- and post- treatment tumor biopsies were available for assessment of ALDH expression as a marker of CSCs and showed a correlation between response and decreased ALDH expression. We also found a correlation between biopsy-proven inhibition of mTOR and response. CONCLUSIONS: Our study adds to the literature supporting the addition of mTOR inhibition to chemotherapy agents for the treatment of sarcomas, and proposes that a mechanism by which mTOR inhibition enhances the efficacy of chemotherapy may be through sensitizing the chemoresistant CSC population. Further study, ideally with pre- and post-therapy assessment of ALDH expression in tumor cells, is warranted.Trial registration The trial was registered on clinicaltrials.gov (NCT00949325) on 30 July 2009. http://www.editorialmanager.com/csrj/default.aspx.

Imatinib-induced drug reaction with eosinophilia and systemic symptoms in solid tumors: a patient with dermatofibrosarcoma protuberans and successful desensitization management.

Drug reaction with eosinophilia and systemic symptoms (DRESS) is a severe, potentially life-threatening drug-induced hypersensitivity reaction, characterized by cutaneous eruptions, fever, diffuse lymphadenopathy, along with hypereosinophilia, and elevated liver function tests, which in severe cases may lead to fulminant hepatic failure and death. Although DRESS syndrome has been associated with over 50 different drugs including imatinib, it has never been reported in association with imatinib treatment in solid tumors. We recently treated a patient with metastatic dermatofibrosarcoma protuberans, a rare cutaneous mesenchymal tumor characterized by constitutive activation of the PDGFß receptor and high sensitivity to imatinib therapy, who had a DRESS reaction to imatinib. Given an initial dramatic clinical and radiological response to treatment and lack of effective alternative targeted therapies, following imatinib discontinuation and resolution of DRESS, we cautiously reintroduced imatinib therapy using a desensitization protocol under the care of the allergy and immunologic clinic. Imatinib was carefully titrated from an initial dose of 50 mg to a target dose of 400 mg daily, while tapering down the prednisone dose. The patient was able to tolerate the treatment without recurrent episodes of DRESS or interruptions, and gained additional 6 months of clinical benefit from imatinib treatment. Although suspected causative drugs should not be reintroduced in DRESS whenever possible, in this case of metastatic disease and lack of effective alternative treatments, a carefully designed drug rechallenge helped minimize the risk of overt clinical reaction and resulted in an overall clinical benefit.

Cost-Effectiveness of Surveillance for Distant Recurrence in Extremity Soft Tissue Sarcoma.

BACKGROUND: Optimal distant recurrence (DR) surveillance strategies for extremity soft tissue sarcoma (STS) are unknown. We performed a cost-effectiveness analysis of different imaging modalities performed at guideline-specified intervals. METHODS: We developed a Markov model simulating lifetime outcomes for 54-year-old patients after definitive treatment for American Joint Committee on Cancer stage II-III extremity STS using four surveillance strategies: watchful waiting (WW), chest X-ray (CXR), chest computed tomography (CCT), and positron emission tomography-computed tomography (PET/CT). Probabilities, utilities, and costs were extracted from the literature and Medicare claims to determine incremental cost-effectiveness ratios (ICER). RESULTS: CCT was the most effective and most costly strategy with CXR the most cost-effective strategy at a societal willing-to-pay (WTP) of $100,000/quality-adjusted life year (QALY). The ICER was $12,113/QALY for CXR versus $104,366/QALY for CCT while PET/CT was never cost-effective. Sensitivity analyses demonstrated CCT becomes the preferred imaging modality as the lifetime risk of DR increases beyond 33% or as the WTP increases beyond $120,000/QALY. CONCLUSIONS: Optimal DR surveillance imaging for stage II-III extremity STS should be individualized based on patients' risks for DR. These results suggest CXR, or CCT performed at more protracted intervals, may be preferred for lower-risk patients (i.e., DR risk <33%), whereas CCT may be preferred for higher-risk patients (i.e., DR risk >33%). Further study of optimal strategies is needed. In the interim, these findings may help to refine guidelines to reduce resource overutilization during routine surveillance of lower-risk sarcoma patients.

Surveillance Imaging Patterns and Outcomes Following Radiation Therapy and Radical Resection for Localized Extremity and Trunk Soft Tissue Sarcoma.

BACKGROUND: Optimal surveillance imaging (SI) regimens following radiation therapy (RT) and radical resection for localized soft tissue sarcoma (STS) are unknown and practice patterns vary. METHODS: Between 2006 and 2014, 94 patients with localized STS of the extremity/trunk treated with preoperative RT and radical resection were identified. Timing of local recurrence (LR), distant recurrence (DR), and SI were evaluated. The Kaplan-Meier method was used to determine recurrence-free and overall survival (OS), and the method of recurrence detection (SI or due to signs/symptoms) was determined. RESULTS: Median tumor size was 7.5 cm, and 92% were intermediate/high grade. After a median follow-up of 60 months for surviving patients, 30 patients (32%) recurred, including 5 LRs and 26 DRs. The median time to LR and DR was 36.2 months (range 14.4-65.7) and 10.4 months (range 5.2-76.9), respectively, and the 5-year local recurrence-free survival (RFS), distant RFS, and OS was 95, 71, and 76%, respectively. Local SI was performed for 90% of patients, mostly by magnetic resonance imaging (MRI; 91%). Of the five LRs, two were detected by SI and three had signs/symptoms preceding imaging. All patients underwent distant SI. Of the 26 DRs, 23 (88%) were in the lung. SI detected 22 (85%) DRs, and only 4 of 26 had signs/symptoms prompting imaging. CONCLUSION: Given excellent local control with RT and radical resection for intermediate/high-grade STS of the extremity/trunk, SI of the primary site should be reserved for select patients at high risk of LR. Conversely, due to frequent occurrence of asymptomatic DR in the lungs, periodic lung SI is appropriate. Routine abdominopelvic SI may not be indicated for most histologies.

Trabectedin: the evidence for its place in therapy in the treatment of soft tissue sarcoma.

INTRODUCTION: Soft tissue sarcoma accounts for less than 1% of all malignant neoplasms and is comprised of a very heterogeneous group of tumors with over 50 different subtypes. Due to its diversity and rarity, developing new therapeutics has been difficult, at best. The standard of care in the treatment of advanced and metastatic disease over the last 30 years has been doxorubicin and ifosfamide, either alone or in combination. There has been significant focus on developing new therapeutics to treat primary and metastatic disease. Trabectedin (ecteinascidin-743) is a tetrahydroiso-quinoline alkaloid which has been evaluated in the treatment of metastatic soft tissue sarcoma. AIMS: To review the current evidence for the therapeutic use of trabectedin in patients with soft tissue sarcoma. EVIDENCE REVIEW: Five phase I studies in patients with solid tumors, all of which include sarcoma patients, evaluating the dosing and toxicity of trabectedin were performed with efficacy being evaluated as a secondary endpoint. Additionally, there are four phase I trials evaluating trabectedin in combination with frontline therapeutic drugs in soft tissue sarcoma. Four phase II studies were performed in soft-tissue sarcoma patients with objective response rates ranging from 3.7% to 17.1%. Additionally, in two compassionate use trials, objective response rates between 14% and 51% were seen, the largest response resulting from a study specifically focusing on liposarcoma. PLACE IN THERAPY: Trabectedin is a potential therapeutic option for the management of soft-tissue sarcoma. It appears to have specific activity in a select group of histologies, most notably myxoid/round cell liposarcoma. Although it would be helpful to study the use of trabectedin in a randomized, controlled fashion, the relative rarity of soft-tissue sarcoma, and heterogeneity of the histologic subtypes, makes phase III trials a difficult prospect.