REGISTRI: Regorafenib in first-line of KIT/PDGFRA wild type metastatic GIST: a collaborative Spanish (GEIS), Italian (ISG) and French Sarcoma Group (FSG) phase II trial

BACKGROUND

Approximately 15% of adult GIST patients harbor tumors that are wild-type for KIT and PDGFRα genes (KP-wtGIST). These tumors usually have SDH deficiencies, exhibit a more indolent behavior and are resistant to imatinib. Underlying oncogenic mechanisms in KP-wtGIST include overexpression of HIF1α high IGFR signaling through the MAPK pathway or BRAF activating mutation, among others. As regorafenib inhibits these signaling pathways, it was hypothesized that it could be more active as upfront therapy in advanced KP-wtGIST.

METHODS

Adult patients with advanced KP-wtGIST after central confirmation by NGS, naïve of systemic treatment for advanced disease, were included in this international phase II trial. Eligible patients received regorafenib 160 mg per day for 21 days every 28 days. The primary endpoint was disease control rate (DCR), according to RECIST 1.1 at 12 weeks by central radiological assessment.

RESULTS

From May 2016 to October 2020, 30 patients were identified as KP-wtGIST by Sanger sequencing and 16 were confirmed by central molecular screening with NGS. Finally, 15 were enrolled and received regorafenib. The study was prematurely closed due to the low accrual worsened by COVID outbreak. The DCR at 12 weeks was 86.7% by central assessment. A subset of 60% experienced some tumor shrinkage, with partial responses and stabilization observed in 13% and 87% respectively, by central assessment. SDH-deficient GIST showed better clinical outcome than other KP-wtGIST.

CONCLUSIONS

Regorafenib activity in KP-wtGIST compares favorably with other tyrosine kinase inhibitors, especially in the SDH-deficient GIST subset and it should be taken into consideration as upfront therapy of advanced KP-wtGIST.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02638766.

Circulating tumor DNA analysis of the phase III VOYAGER trial: KIT mutational landscape and outcomes in patients with advanced gastrointestinal stromal tumor treated with avapritinib or regorafenib

BACKGROUND

The current treatment paradigm of imatinib-resistant metastatic gastrointestinal stromal tumor (GIST) does not incorporate KIT/PDGFRA genotypes in therapeutic drug sequencing, except for PDGFRA exon 18-mutant GIST that is indicated for avapritinib treatment. Here, circulating tumor DNA (ctDNA) sequencing was used to analyze plasma samples prospectively collected in the phase III VOYAGER trial to understand how the KIT/PDGFRA mutational landscape contributes to tyrosine kinase inhibitor (TKI) resistance and to determine its clinical validity and utility.

PATIENTS AND METHODS

VOYAGER (N = 476) compared avapritinib with regorafenib in patients with KIT/PDGFRA-mutant GIST previously treated with imatinib and one or two additional TKIs (NCT03465722). KIT/PDGFRA ctDNA mutation profiling of plasma samples at baseline and end of treatment was assessed with 74-gene Guardant360® CDx. Molecular subgroups were determined and correlated with outcomes.

RESULTS

A total of 386/476 patients with KIT/PDGFRA-mutant tumors underwent baseline (pre-trial treatment) ctDNA analysis; 196 received avapritinib and 190 received regorafenib. KIT and PDGFRA mutations were detected in 75.1% and 5.4%, respectively. KIT resistance mutations were found in the activation loop (A-loop; 80.4%) and ATP-binding pocket (ATP-BP; 40.8%); 23.4% had both. An average of 2.6 KIT mutations were detected per patient; 17.2% showed 4-14 different KIT resistance mutations. Of all pathogenic KIT variants, 28.0% were novel, including alterations in exons/codons previously unreported. PDGFRA mutations showed similar patterns. ctDNA-detected KIT ATP-BP mutations negatively prognosticated avapritinib activity, with a median progression-free survival (mPFS) of 1.9 versus 5.6 months for regorafenib. mPFS for regorafenib did not vary regardless of the presence or absence of ATP-BP/A-loop mutants and was greater than mPFS with avapritinib in this population. Secondary KIT ATP-BP pocket mutation variants, particularly V654A, were enriched upon disease progression with avapritinib.

CONCLUSIONS

ctDNA sequencing efficiently detects KIT/PDGFRA mutations and prognosticates outcomes in patients with TKI-resistant GIST treated with avapritinib. ctDNA analysis can be used to monitor disease progression and provide more personalized treatment.

The multifaceted landscape behind imatinib resistance in gastrointestinal stromal tumors (GISTs): A lesson from ripretinib

Gastrointestinal stromal tumors (GISTs) are rare mesenchymal sarcomas and the gold-standard treatment is represented by tyrosine kinase inhibitors (TKIs). Unfortunately, first-line treatment with the TKI imatinib usually promotes partial response or stable disease rather than a complete response, and resistance appears in most patients. Adaptive mechanisms are immediately relevant at the beginning of imatinib therapy, and they may represent the reason behind the low complete response rates observed in GISTs. Concurrently, resistant subclones can silently continue to grow or emerge de novo, becoming the most representative populations. Therefore, a slow evolution of the primary tumor gradually occurs during imatinib treatment, enriching heterogeneous imatinib resistant clonal subpopulations. The identification of secondary KIT/PDGFRA mutations in resistant GISTs prompted the development of novel multi-targeted TKIs, leading to the approval of sunitinib, regorafenib, and ripretinib. Although ripretinib has broad anti-KIT and -PDGFRA activity, it failed to overcome sunitinib as second-line treatment, suggesting that imatinib resistance is more multifaceted than initially thought. The present review summarizes several biological aspects suggesting that heterogeneous adaptive and resistance mechanisms can also be driven by KIT or PDGFRA downstream mediators, alternative kinases, as well as ncRNAs, which are not targeted by any TKI, including ripretinib. This may explain the modest effect observed with ripretinib and all anti-GIST agents in patients.

Abstract 3887: ATP-binding pocket substitutions as secondary or tertiary in-cis mutations are major on-target ripretinib resistance mechanisms in gastrointestinal stromal tumor

Introduction: Ripretinib (Rip) is a kinase inhibitor with broad preclinical activity against mutant KIT. Based on the INVICTUS trial, Rip was approved for patients with Gastrointestinal Stromal Tumors (GIST) after treatment with 3 or more kinase inhibitors. Most patients in this ≥4th-line setting progress on Rip within one year. Here, we characterized Rip-progressing GIST samples to identify resistance mechanisms.

Methods: Progressing lesions in 25 patients were analyzed by NGS after Rip failure. KIT mutations (muts) were recapitulated by gene editing. Activities of Rip, sunitinib (SU), and novel TKIs were characterized by cell viability assays and immunoblot. Mutagenesis experiments were performed using ENU. SU- and Rip-resistant cell lines were pooled and treated with various regimens, with clonal composition deconvoluted by cDNA-based amplicon sequencing.

Results: 19/25 Rip-progressing GISTs displayed muts in the ATP-binding pocket (ATP-BP; e13/14). Four of these had pre-existing muts in the activation loop (AL; e17/18), which were confirmed to be in-cis with the primary and ATP-BP muts (triple in cis; TIC). Mutagenesis screens using a double KIT-mutant GIST line (e11 + AL) as a starting point confirmed that TIC-muts are a predominant escape mechanism when treated with Rip. A GIST subline (T1-triple) with TIC-muts in e11, e18 (A829P), and e13 (V654A) was highly resistant to Rip (GR50 > 2µM). Structural analyses of ATP-BP muts suggest steric interference and loss of van der Waals interactions that impede Rip binding and thereby confer Rip resistance. Another 3/25 Rip-progressing GISTs harbored pathogenic KIT muts in e9 only. A novel GIST cell line with primary KIT e9 mut (T1-e9) was 14-fold less sensitive to Rip than isogenic e11-driven cells (GR50 = 115 vs 8nM). Notably, adding a typical AL mut to T1-e9 (T1-e9-N822K) sensitized the cells to Rip (GR50 = 20nM). Immunoblots showed >95% inhibition of phospho-KIT in AL-mutant cell lines at Rip 100nM, whereas inhibition was weaker in T1-e9 (77%) and T1-V654A (46%), and absent in T1-triple. A compound screen of FDA-approved kinase inhibitors identified Nintedanib (NIN) as the most active compound against T1-triple. Clonal outgrowth assays of mixed cultures revealed SU (93% inhibition), and a weekly switch between Rip and either SU (96%) or NIN (79%) as the most effective inhibitors of pooled cell growth.

Conclusions: KIT e9 primary muts and e13/14 (ATP-BP) secondary muts are enriched in post-progression biopsies following Rip treatment. KIT TIC-muts are novel frequent events driving GIST clinical progression and confer a high degree of resistance. Strategies to overcome resistance may include combinations or sequences of approved drugs, and novel drugs that more efficiently inhibit TIC-mutant KIT.

Citation Format: Thomas Mühlenberg, Johanna Falkenhorst, Tom Schulz, Benjamin S. Fletcher, Alina Teuber, Dawid Krzeciesa, Isabella Klooster, Jonas Lategahn, Wen-Bin Ou, Meijun Lundberg, Margaret von Mehren, Susanne Grunewald, Alicia I. Tüns, Mehdi Brahmi, Michael C. Heinrich, Cesar Serrano, Hans-Ulrich Schildhaus, Sonja Sievers, Jürgen Treckmann, Lydia Wilson, Chandrajit P. Raut, Adrian Marino-Enriquez, Suzanne George, Daniel Rauh, Jonathan A. Fletcher, Sebastian Bauer. ATP-binding pocket substitutions as secondary or tertiary in-cis mutations are major on-target ripretinib resistance mechanisms in gastrointestinal stromal tumor. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3887.

Nutritional management and clinical outcome of critically ill patients with COVID-19: A retrospective study in a tertiary hospital

BACKGROUND & AIMS

Severe COVID-19 infection is characterized by an inflammatory response and lung injury that can evolve into an acute respiratory distress syndrome that needs support treatment in intensive care unit. Nutritional treatment is an important component of the management of critically ill patients and should be started in the first 48 h of ICU admission to avoid malnutrition. This study describes the characteristics of the patients treated in a tertiary hospital in Madrid during the months of March-May 2020 (first wave), the medical nutrition treatment employed and its influence in the clinical outcome of these patients.

METHODS

This is a retrospective study including COVID-19 patients admitted in ICU that needed medical nutrition treatment (MNT). Collected variables included sex, age, BMI, underlying diseases, time from hospitalisation to ICU admission, type of respiratory support (invasive mechanical ventilation (IMV) or high flow nasal cannula (HFNC) or non-invasive ventilation (non-IMV)), caloric and protein requirements (25 kcal/kg adjusted body weight (ABW), 1.3 g/kg ABW/day), MNT type (enteral nutrition (EN), parenteral nutrition (PN), mixed EN + PN), total calories (including propofol) and proteins administered, percentage of caloric and protein goal in ICU day 4th and 7th, metabolic complications, acute kidney failure (AKF), length of stay (LOS) and mortality. Data are expressed as mean ± SD, median (IQR) or frequencies. Statistical analysis was performed with the IBM SPSS Statistics for Windows, Version 25.0. p < 0.05 were considered statistically significant.

RESULTS

A total of 176 patients were included (72.7% male), 60.1 ± 13.5 years, BMI 29.9 ± 5.4 kg/m². Underlying diseases included 47.4% overweight, 39.8% obesity, 49.1% hypertension, 41.4% dyslipidaemia. 88.6% of patients needed IMV, 89.1% prone position, 2.9% ECMO. Time to ICU admission: 2 (4.75) days. Estimated caloric and protein requirements were 1775 ± 202 kcal and 92.4 ± 10.3 g. Calories and proteins administered at days 4th and 7th were 1425 ± 577 kcal and 66 ± 26 g and 1574 ± 555 and 74 ± 37, respectively. Most of the patients received PN (alone or complementary to EN) to cover nutritional requirements (82.4% at day 4th and 77.9% at day 7th). IVM patients received more calories and proteins during the first week of ICU admission. Complications included 77.8% hyperglycaemia, 13.2% hypoglycaemia, 83.8% hypertriglyceridemia, and 35.1% AKF. ICU LOS was 20.5 (26) days. The mortality rate was 36.4%.

CONCLUSIONS

In our series, the majority of patients reached energy and protein requirements in the first week of ICU admission due to the use of PN (total or complementary to EN). Patients with HFNC or non-IMV may be at risk of malnutrition if total or complementary PN to oral diet/ONS/tube feeding is not used to cover nutritional requirements. Therefore, if EN is not possible or insufficient, PN can be safely used in critically ill patients with COVID-19 with a close monitoring of metabolic complications.

miRNA Expression May Have Implications for Immunotherapy in PDGFRA Mutant GISTs

Gastrointestinal stromal tumors (GISTs) harboring mutations in the PDGFRA gene occur in only about 5-7% of patients. The most common PDGFRA mutation is exon 18 D842V, which is correlated with specific clinico-pathological features compared to the other PDGFRA mutated GISTs. Herein, we present a miRNA expression profile comparison of PDGFRA D842V mutant GISTs and PDGFRA with mutations other than D842V (non-D842V). miRNA expression profiling was carried out on 10 patients using a TLDA miRNA array. Then, miRNA expression was followed by bioinformatic analysis aimed at evaluating differential expression, pathway enrichment, and miRNA-mRNA networks. We highlighted 24 differentially expressed miRNAs between D842V and non-D842V GIST patients. Pathway enrichment analysis showed that deregulated miRNAs targeted genes that are mainly involved in the immune response pathways. The miRNA-mRNA networks highlighted a signature of miRNAs/mRNA that could explain the indolent behavior of the D842V mutated GIST. The results highlighted a different miRNA fingerprint in PDGFRA D842V GISTs compared to non-D842Vmutated patients, which could explain the different biological behavior of this GIST subset.

Abstract LB565: Efficacy of a highly potent and selective KIT V654A inhibitor for treatment of imatinib resistant GIST

Gastrointestinal stromal tumor (GIST) is the most common type of sarcoma, with approximately 5,000 patients diagnosed per year in the US. Approximately 80% of patients with GIST present with mutations in the c-KIT oncogene at exon 9 or 11, which leads to constitutive, ligand-independent activation of the KIT receptor tyrosine kinase. For patients with metastatic GIST, frontline therapy with imatinib is effective, with a response rate of approximately 51-54% and median progression-free survival (PFS) of 19-23 months, in a molecularly unselected population. Other agents are approved for advanced GIST, without molecular selection, after progression on imatinib, including sunitinib, regorafenib, and ripretinib; however, response rates are less than 10% with PFS of approximately 5-6 months. Notably, patients who progress on imatinib and other tyrosine kinase inhibitors may develop a variety of on-target resistance mutations in the KIT oncogene, such as those in exon 17 (including at amino acids D816 and D820, activation loop mutation), exon 13 (V654A, ATP-binding region mutation), and less frequently in exon 14 (T670I, gatekeeper mutation). Several KIT inhibitors have been developed to potently target the exon 17 resistance mutations (avapritinib and ripretinib); however, there remains an important medical need in 2nd- and 3rd-line therapy in a molecularly unselected population of imatinib-resistant GIST. This suggests more broad-spectrum KIT inhibition is likely required, a hypothesis supported by the observation of large inter- and intra-patient heterogeneity of KIT secondary mutations across hundreds of samples obtained from patients with GIST treated with avapritinib. Sequencing data from the NAVIGATOR phase 1 trial (NCT02508532) revealed that patients with KIT mutant GIST and with the KIT V654A secondary resistance mutation had a poor response to treatment with avapritinib. To address this, we developed a highly potent and selective inhibitor of KIT V654A. This inhibitor showed dose-dependent modulation of downstream pharmacodynamic markers and induced tumor regression in a mastocytoma xenograft model driven by an exon 11 plus 13 V654A resistance mutation. Importantly, this inhibitor was generally well-tolerated and showed high selectivity over wild-type KIT. These findings suggest this novel KIT inhibitor has the potential to be used as a single agent or combination therapy for patients with imatinib-resistant GIST harboring the KIT V654A mutation.

Citation Format: Alexandra R. Grassian, Joseph Kim, Omar Ahmad, Kevin Barvian, Alison Davis, Tom Dineen, Wei Hu, Ebby Job, Ludivine Moine, Kate Newberry, Maria Roche, Doug Shorten, Yeon Sook Choi, Francis Wolenski, Sebastian Bauer, Cesar Serrano, Jonathan Trent, Suzanne George. Efficacy of a highly potent and selective KIT V654A inhibitor for treatment of imatinib resistant GIST [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB565.

Circulating tumor DNA (ctDNA) analyses of the phase III VOYAGER trial: KIT mutational landscape and outcomes in patients with advanced gastrointestinal stromal tumor (GIST)

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Background: The genotype of primary mutations predicts imatinib response in untreated metastatic GIST. However, the sequence of salvage treatments in metastatic GIST is based solely on the chronological order of registration trials. ctDNA sequencing offers a powerful diagnostic tool to detect resistance mutations in GIST but has not been shown to correlate with outcomes in clinical trials of pretreated patients (pts). We analyzed ctDNA samples collected at baseline in the phase III VOYAGER trial (NCT03465722) to describe the landscape of KIT alterations and its association with outcomes of pts treated with avapritinib or regorafenib. Methods: In VOYAGER, 476 pts with advanced KIT-mutant GIST were randomly assigned to avapritinib (240 pts) or regorafenib (236 pts) in 3rd-4th line. Baseline plasma was collected and ctDNA analyzed with the Guardant 360 (G360), 74-gene panel. KIT molecular subgroups were determined and correlated with outcomes. PDGFRA-mutant GISTs were excluded from outcomes analysis. Results: Baseline ctDNA analysis was performed in 386/476 pts (81%). ctDNA was detected in 333 pts (86%), with 250 and 18 pts showing at least one KIT (75%) or PDGFRA (5%) variant, respectively. KIT primary mutations were detected in 71% pts (exon 11, 56%; exon 9, 14%; exon 13, 1%) and KIT secondary mutations in 55% of pts. Activation loop (AL, exons 17 and 18) was more commonly affected (44%) than the ATP-binding pocket (ABP, exons 13 and 14; 23%). Among KIT-mutant tumors, multiple KIT mutations were commonly detected within individual tumors (mean, 2.56; range, 1-14). Notably, 17% of pts had > 3 mutations (mean, 6.07; range, 4 to 14). Median PFS and OS were shorter for patients whose ctDNA was positive for V654A or T670I (ABP hot spots) when treated with avapritinib vs. regorafenib: mPFS, 1.9 mo vs. 7.4 mo; log-rank p <.001; mOS, 8.3 mo vs. 11.7 mo; log rank p =.0651. mPFS was shorter for patients with ctDNA positive for KIT exon 17 mutation if concurrently KIT V654A/T670I was absent when treated with avapritinib, with no difference in OS: mPFS, 4.7 mo vs. 6.7 mo; log-rank p =.03; mOS, 19.2 mo vs. NR; log-rank p =.628. mPFS on avapritinib was longer when ABP mutations were absent when compared to those with ABP present (5.6 vs. 1.9 mo; log-rank p <.001). There were no differences considering AL mutations vs. no AL mutations (3.8 vs. 3.9 mo; log-rank p =.622) when treated with avapritinib. Regorafenib showed similar activity regardless of KIT mutational status and the location of KIT mutation. Conclusions: Hybrid capture-based plasma sequencing detects ctDNA in the majority of patients with advanced TKI-resistant GIST, including heterogeneity of KIT mutations. This study is the first to show that ctDNA sequencing correlates with outcomes in pretreated GIST. Identification of ABP (exon13/14) KIT mutations negatively correlates with avapritinib activity.

KIT resistance mutations identified by circulating tumor DNA and treatment outcomes in advanced gastrointestinal stromal tumor

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Background: Tyrosine kinase inhibitors (TKIs) are the cornerstone treatment for advanced GIST via pharmacologic targeting of driver oncogenes such as KIT. Detection of KIT alterations through tissue-based next-generation sequencing (NGS) is common, but circulating tumor DNA (ctDNA)-based NGS is a less invasive alternative to identify driver and resistance mutations in advanced GIST. Patients (pts) with KIT-mutant GIST benefit from first-line (1L) imatinib; however, KIT resistance mutations may confer imatinib-resistance and differential sensitivity to subsequent TKIs. We sought to analyze ctDNA from GIST pts to determine whether certain resistance mutations were associated with superior outcomes with particular TKIs in the second-line and beyond (2L+). Methods: Under an approved institutional review board protocol, a retrospective analysis was performed with available ctDNA NGS results (Guardant360; Redwood City, CA) from pts (N = 104) who progressed on 1L imatinib between 2017-21. Using R statistical programming, we identified pts with primary KIT alterations (N = 64) and known resistance mutations in KIT exons 13 (N = 25) and 17 (N = 35). We studied the median time to treatment failure (mTTF), defined as the time from treatment start to treatment end (months) due to progressive disease or toxicity, for each 2L+ drug. Using Kaplan-Meier methods, we calculated Cox proportional-hazard ratios (HR) with confidence intervals (CI) and p-values for statistical significance. Results: 49% were male (median age 66; range, 31-94). Driver oncogenes were detected in 80% (N = 83), including KIT, NF1, PDGFRA and BRAF. Of those with a KIT alteration, 12 (19%) had KIT exon 9 mutations and 52 (81%) had KIT exon 11 mutations. KIT resistance mutations were observed in KIT exons 13 (N = 25; V654), 14 (N = 2; T670), and 17 (N = 45; D816, D820, N822, Y823). Pts with KIT resistance mutations received 2L+ therapy with avapritinib, dose-escalated imatinib, nilotinib, pazopanib, ponatinib, regorafenib, ripretinib, or sunitinib. mTTF for KIT exon 13 V654 pts treated with 2L+ sunitinib, imatinib 800mg, or other was 10.8, 7.5, and 3.7 months, respectively. TTF for sunitinib vs other 2L+ drugs showed a HR of 0.51 (CI 0.33-0.8), p = 0.003. mTTF for KIT exon 17 (non-V654) pts treated with 2L+ regorafenib, imatinib 800mg, or other was 4.6, 1.2, and 6.3 months, respectively. Comparison of mTTF for regorafenib vs other 2L+ drugs was not statistically significant. Conclusions: ctDNA is a noninvasive tool for detecting driver and resistance mutations in pts with advanced GIST. GIST pts with KIT exon 13 V654 resistance mutations had superior outcomes in the 2L+ setting with sunitinib. Regorafenib was not superior to other 2L+ TKIs in pts with KIT exon 17 resistance mutations, possibly due to their own activity against exon 17 resistance alterations. ctDNA-guided therapy warrants evaluation in a prospective clinical trial.

Analysis of microbiome in GISTs: looking for different players in tumorigenesis and novel therapeutic options

Preclinical forms of gastrointestinal stromal tumor (GIST), small asymptomatic lesions, called microGIST, are detected in approximately 30% of the general population. Gastrointestinal stromal tumor driver mutation can be already detected in microGISTs, even if they do not progress into malignant cancer; these mutations are necessary, but insufficient events to foster tumor progression. Here we profiled the tissue microbiota of 60 gastrointestinal specimens in three different patient cohorts—micro, low‐risk, and high‐risk or metastatic GIST—exploring the compositional structure, predicted function, and microbial networks, with the aim of providing a complete overview of microbial ecology in GIST and its preclinical form. Comparing microGISTs and GISTs, both weighted and unweighted UniFrac and Bray–Curtis dissimilarities showed significant community‐level separation between them and a pronounced difference in Proteobacteria, Firmicutes, and Bacteroidota was observed. Through the LEfSe tool, potential microbial biomarkers associated with a specific type of lesion were identified. In particular, GIST samples were significantly enriched in the phylum Proteobacteria compared to microGISTs. Several pathways involved in sugar metabolism were also highlighted in GISTs; this was expected as cancer usually displays high aerobic glycolysis in place of oxidative phosphorylation and rise of glucose flux to promote anabolic request. Our results highlight that specific differences do exist in the tissue microbiome community between GIST and benign lesions and that microbiome restructuration can drive the carcinogenesis process.

A phase Ib/II study of selinexor in combination with imatinib in patients with advanced gastrointestinal stromal tumor (GIST): SeliGIST/GEIS-41 trial

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Background: KIT or PDGFRA oncogenic activation drives GIST progression throughout the disease course. Accordingly, currently approved agents in metastatic GIST focus on the therapeutic suppression of these receptors. However, the clinical benefit after imatinib (IM) progression is still modest, suggesting the co-operation of KIT/PDGFRA-independent mechanisms in GIST cell survival. Selinexor is an oral, selective inhibitor of XPO1-mediated nuclear export, and preclinical studies evidenced antitumoral activity in GIST as single agent and in combination with IM in both IM-sensitive and IM-resistant models. Methods: The phase Ib portion studied IM 400 mg daily plus weekly selinexor in patients (pts) with IM-resistant, advanced GIST. Prior intolerance to IM was not allowed. A standard 3+3 dosing schema was utilized to determine the recommended phase II dose (RP2D) of this combination. Investigator-assessed response was evaluated every 8 weeks using RECIST 1.1. Results: At data cutoff of Sep 25, 2020, 12 pts were enrolled and received treatment with IM 400 mg and selinexor once weekly at dose levels (DL) 1 (60 mg), DL2 (80 mg) and DL3 (100 mg). Median age 57 (range 46-77), 42% female, median prior therapies 4 (range 2-7). Although only 1/6 pts developed a dose limiting toxicity (DLT) at DL3, the RP2D was defined at DL2 (IM 400 mg daily and selinexor 80 mg once weekly) based on activity data in the DL2 and the need for dose reductions in 5/6 pts at DL3 after the DLT window. All pts were evaluable for toxicity and response. One DLT occurred at DL3 (G3 nausea). Non-DLT G3/4 toxicities were anemia (1/12 pts), neutropenia (1/12 pts), vomiting (1/12 pts) and fatigue (2/12 pts). Common G1/2 toxicities were nausea (11/12 pts), vomiting (10/12 pts), neutropenia (5/12 pts) and anemia, fatigue, diarrhea, and periorbital edema (4/12 pts each). No unexpected toxicities were observed. Overall response rate in the 12 pts evaluable for response was 67% (95% CI 0.349-0.901), with 2 pts achieving PR (17%) and 6 pts SD (50%) as the best response. Clinical benefit rate (CBR = CR, PR, SD) ≥ 16 weeks was 42% (95% CI 0.157-0.723). Median progression free survival was 3.5 months (95% CI 1.7-7.3). Four pts remain on trial at data cutoff. Conclusions: IM and selinexor combination is well-tolerated and has clinical activity in heavily pretreated GIST pts. The trial is currently exploring selinexor as single agent in the IM-resistant GIST population. Clinical trial information: NCT04138381.

Intra-patient dose escalation (IPDE) of ripretinib after disease progression in patients with advanced gastrointestinal stromal tumor (GIST): Analyses from the phase 3 INVICTUS study

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Background: Ripretinib is a switch-control tyrosine kinase inhibitor that broadly inhibits KIT and PDGFRA kinase signaling. In the INVICTUS study (NCT03353753), patients with advanced GIST (≥4th-line) receiving ripretinib had a median progression-free survival (mPFS) of 6.3 months vs 1.0 month for patients receiving placebo (HR = 0.15, p <0.0001). In an earlier phase 1 dose escalation study, the maximum tolerated dose was not reached with doses up to 200 mg twice daily (BID). Here, we report efficacy, safety, and pharmacokinetic data for IPDE patients initially randomized to ripretinib from the phase 3 INVICTUS study based on data as of 10 Aug 2020. Methods: A total of 129 patients were randomized 2:1 to ripretinib 150 mg once daily (QD; n = 85) or placebo (n = 44). Patients receiving ripretinib 150 mg QD who had progressive disease (PD) as assessed by blinded independent central review (BICR) using mRECIST were given the option for IPDE to 150 mg BID. Tumor response assessments were performed every 28 days for 4 cycles and every 56 days thereafter (including after IPDE). The primary endpoint was PFS. For this exploratory analysis, PFS1 for IPDE patients was defined as the time from randomization to PD; PFS2 for IPDE patients was the time from the first dose of ripretinib 150 mg BID to PD or death. PFS1 and PFS2 were based on BICR. Results: Of 85 patients treated with ripretinib 150 mg QD, 43 patients with BICR PD dose escalated to 150 mg BID. Baseline characteristics of IPDE patients at time of study entry were similar to those observed in the original ripretinib QD arm and similar to the 22 patients with BICR PD who either remained on 150 mg QD or discontinued treatment. IPDE patients had a mPFS1 of 4.6 months (95% CI, 2.7–6.4) and a mPFS2 of 3.7 months (95% CI, 3.1–5.3); mPFS2/mPFS1=80%. The IPDE dosing period was well tolerated without the emergence of new safety concerns. The most common new or worsening (unchanged or improving grades not included) treatment-emergent adverse event (TEAE) for IPDE patients during the BID period was abdominal pain (30.2% all grades and 7% Grade 3–4 vs 41.9% and 4.7% in QD period, respectively). The most common Grade 3–4 TEAE in the BID period was anemia (14% vs 2.3% in QD period). IPDE from QD to BID resulted in an approximately 2-fold increase in the steady state trough concentration. Conclusions: Similar to the phase 1 study wherein IPDE to 150 mg BID following PD provided clinical benefit with a mPFS1 of 5.5 months and mPFS2 of 4.6 months (mPFS2/mPFS1=84%) for patients with ≥4th-line GIST, these analyses from INVICTUS indicate that IPDE to ripretinib 150 mg BID can also provide additional meaningful clinical benefit and a similar tolerability profile to the 150 mg QD regimen for patients with ≥4th-line GIST that progressed following treatment with ripretinib 150 mg QD. Clinical trial information: NCT03353753.

Avapritinib in Patients With Advanced Gastrointestinal Stromal Tumors Following at Least Three Prior Lines of Therapy

BACKGROUND

Most gastrointestinal stromal tumors (GIST) driven by KIT or platelet-derived growth factor receptor A (PDGFRA) mutations develop resistance to available tyrosine kinase inhibitor (TKI) treatments. NAVIGATOR is a two-part, single-arm, dose escalation and expansion study designed to evaluate safety and antineoplastic activity of avapritinib, a selective, potent inhibitor of KIT and PDGFRA, in patients with unresectable or metastatic GIST.

MATERIALS AND METHODS

Eligible patients were 18 years or older with histologically or cytologically confirmed unresectable GIST and Eastern Cooperative Oncology Group performance status ≤2 and initiated avapritinib at 300 mg or 400 mg once daily. Primary endpoints were safety in patients who initiated avapritinib at 300 mg or 400 mg once daily and overall response rate (ORR) in patients in the safety population with three or more previous lines of TKI therapy.

RESULTS

As of November 16, 2018, in the safety population (n = 204), the most common adverse events (AEs) were nausea (131 [64%]), fatigue (113 [55%]), anemia (102 [50%]), cognitive effects (84 [41%]), and periorbital edema (83 [41%]); 17 (8%) patients discontinued due to treatment-related AEs, most frequently confusion, encephalopathy, and fatigue. ORR in response-evaluable patients with GIST harboring KIT or non-D842V PDGFRA mutations and with at least three prior therapies (n = 103) was 17% (95% confidence interval [CI], 10-25). Median duration of response was 10.2 months (95% CI, 7.2-10.2), and median progression-free survival was 3.7 months (95% CI, 2.8-4.6).

CONCLUSION

Avapritinib has manageable toxicity with meaningful clinical activity as fourth-line or later treatment in some patients with GIST with KIT or PDGFRA mutations.

IMPLICATIONS FOR PRACTICE

In the NAVIGATOR trial, avapritinib, an inhibitor of KIT and platelet-derived growth factor receptor A tyrosine kinases, provided durable responses in a proportion of patients with advanced gastrointestinal stromal tumors (GIST) who had received three or more prior therapies. Avapritinib had a tolerable safety profile, with cognitive adverse events manageable with dose interruptions and modification in most cases. These findings indicate that avapritinib can elicit durable treatment responses in some patients with heavily pretreated GIST, for whom limited treatment options exist.

Diagnosis and management of tropomyosin receptor kinase (TRK) fusion sarcomas: expert recommendations from the World Sarcoma Network

Sarcomas are a heterogeneous group of malignancies with mesenchymal lineage differentiation. The discovery of neurotrophic tyrosine receptor kinase (NTRK) gene fusions as tissue-agnostic oncogenic drivers has led to new personalized therapies for a subset of patients with sarcoma in the form of tropomyosin receptor kinase (TRK) inhibitors. NTRK gene rearrangements and fusion transcripts can be detected with different molecular pathology techniques, while TRK protein expression can be demonstrated with immunohistochemistry. The rarity and diagnostic complexity of NTRK gene fusions raise a number of questions and challenges for clinicians. To address these challenges, the World Sarcoma Network convened two meetings of expert adult oncologists and pathologists and subsequently developed this article to provide practical guidance on the management of patients with sarcoma harboring NTRK gene fusions. We propose a diagnostic strategy that considers disease stage and histologic and molecular subtypes to facilitate routine testing for TRK expression and subsequent testing for NTRK gene fusions.

Thermography for the differential diagnosis of vascular malformations

Vascular malformations classification may pose a diagnostic challenge for physicians. In the early stages, they are diagnosed clinically mainly by visual inspection. For a deeper analysis, Doppler ultrasonography is the preferred technique to determine the haemodynamic behaviour of the anomaly. However, this imaging method is not always available and it requires trained operators to acquire and interpret the images. There is a lack of portable and user-friendly systems that may help physicians in the assessment of vascular malformations. We propose a new diagnostic procedure, more affordable and easier to use, based on a portable thermal camera. This technique provides information about temperature, which has been found to be correlated with the flow rate of the lesion. In our study, > 60 vascular malformations of previously diagnosed patients were analysed with a thermal camera to classify them into low-flow and high-flow malformations. The value was 1 for both sensitivity and specificity of this technique.

Quality of life (QoL) and self-reported function with ripretinib in ≥4th-line therapy for patients with gastrointestinal stromal tumors (GIST): Analyses from INVICTUS

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Background: Ripretinib is a novel switch-control tyrosine kinase inhibitor (TKI) that broadly inhibits KIT and PDGFRA kinase signaling through a dual mechanism of action. In INVICTUS (NCT03353753), a randomized, double-blind, placebo-controlled trial of ripretinib in ≥4th-line advanced GIST, ripretinib reduced the risk of disease progression or death by 85% vs placebo and had a favorable overall safety profile in patients previously treated with ≥3 prior TKIs. Methods: As part of the INVICTUS trial, patient reported outcome (PRO) measures were collected using EQ-5D-5L (EQ5D) and EORTC QLQ-C30 (C30). In prespecified and additional analyses, ANCOVA models were built to compare changes from baseline to cycle 2 day 1 (C2D1) for PRO measures within the ripretinib and placebo arms and determine the difference between treatment arms. PRO measures included the EQ5D visual analogue scale (VAS) and the C30 physical functioning (PF) and role functioning (RF) scales (all scores range from 0–100; higher scores are better). The C30 overall health and overall QoL questions were also assessed (scores range from 1–7; higher scores are better). Fixed effects included treatment arm, number of previous anticancer treatments (3 vs ≥4), and ECOG score at baseline (0 vs 1/2). Results: Overall, 129 patients were randomized and 128 received treatment (85 to ripretinib 150 mg QD; 43 to placebo). All PRO p-values are nominal, and no statistical significance is being claimed. VAS scores improved an average 3.7 points from baseline to C2D1 with ripretinib vs an average decline of 8.9 with placebo (P = 0.004; improvement or no change, 67% vs 41% of patients, respectively). Similarly, the average PF score improved 1.6 points with ripretinib and decreased 8.9 with placebo (P = 0.004; improvement or no change, 68% vs 44%). RF scores also improved an average of 3.5 points with ripretinib vs a decrease of 17.1 with placebo (P = 0.001; improvement or no change, 77% vs 50%). For the overall health and overall QoL questions, scores increased with ripretinib an average of 0.20 and 0.28, respectively, and decreased 0.78 and 0.76 with placebo (both P = 0.001; improvement or no change, 74% vs 47% and 79% vs 59%, respectively). Conclusions: Based on the 5 PRO measures assessed, when compared with placebo and best supportive care, ripretinib provided patient-benefit in advanced GIST with PRO measures of role and physical function, VAS, overall health, and overall QoL remaining stable. Clinical trial information: NCT03353753 .

Safety profile of ripretinib, including impact of alopecia, and Palmar-Plantar Erythrodysesthesia Syndrome (PPES) on patient-reported outcomes (PROs), in ≥ fourth-line advanced gastrointestinal stromal tumors (GIST): Analyses from INVICTUS

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Background: Ripretinib is a novel switch-control TKI that broadly inhibits KIT and PDGFRA kinase signaling. In INVICTUS (NCT03353753), a randomized, double-blind, placebo (PBO)-controlled trial of ripretinib in ≥4th-line advanced GIST, ripretinib reduced the risk of disease progression or death by 85% vs PBO with a favorable overall safety profile. Common ( > 20%) adverse events (AEs) included, but were not limited to, alopecia and PPES. Exploratory analyses evaluated the impact of alopecia and PPES on quality of life (QoL). Methods: Patients (pts) with advanced GIST previously treated with at least imatinib, sunitinib, and regorafenib were randomized (2:1) to ripretinib 150 mg QD or PBO. AEs were graded using CTCAE v4 and PROs collected using EQ-5D-5L (EQ5D) and EORTC QLQ-C30 (C30). Repeated measures (RM) models assessed the impact of alopecia and PPES on 5 PROs (EQ5D visual analogue scale; and C30 physical functioning, role functioning, and the overall health and overall QoL questions) within the ripretinib arm. Fixed effects were sex, alopecia/PPES, and ECOG scores at baseline. Results: 128/129 randomized pts received treatment (85 ripretinib 150 mg QD; 43 PBO). Alopecia, regardless of causality, occurred in 44 (51.8%) on ripretinib (34 [40.0%] grade 1; 10 [11.8%] grade 2) and 2 (4.7%) on PBO (both grade 1). PPES occurred in 18 (21.2%) on ripretinib (11 [12.9%] grade 1; 7 [8.2%] grade 2); none on PBO. The median times in days to first occurrence and worst severity grade with ripretinib were 57.0 and 62.5 for alopecia; 56.5 and 57.0 for PPES. The RM models showed a slight trend towards improvement in PRO score over time for pts with alopecia; the only association reaching a P-value of < 0.05 was between alopecia and increased overall QoL. None of the associations between PPES and PRO scores reach P < 0.05. All PRO p-values are nominal, and no statistical significance is being claimed. Conclusions: Ripretinib had a favorable overall safety and tolerability profile. When stratified by alopecia and PPES, patient-reported assessments of function, overall health, and overall QoL were maintained over time. For both alopecia and PPES, onset and maximum severity occurred almost simultaneously, indicating that these events generally did not progressively worsen. These results suggest that alopecia and PPES are manageable and do not have a negative effect on function, overall health, and QoL. Clinical trial information: NCT03353753 .

The role of previous radical local treatment (RLT) on the outcome of immune checkpoint inhibitors (ICI) in patients (pts) with metastatic urothelial carcinoma (mUC)

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Background: There is a growing interest in local treatment for metastatic solid tumors. Recently, retrospective studies have reported the potential benefit of RLT to primary bladder cancer in pts with metastatic disease. We tested the impact of previous RLT in pts with mUC treated with ICI. Methods: Data from pts with mUC treated with ICI collected between May 2013 and May 2019 using a multi-institutional database was evaluated. Stratification was made according to previous RLT with ICI versus no RLT with ICI. We defined RLT as radical surgery (RS) or ≥50 Gy of radiotherapy (RT) delivered to the bladder. The X2 test was used to determine differences in rates. Overall survival (OS) between previous RLT plus ICI (group A) versus no RLT plus ICI (group B) generated using Kaplan-Meier method was compared by log-rank test. OS was calculated from the date of initiation of ICI to the date of death. Analyses were performed using SPSS v21. Results: A total of 115 pts with mUC were treated with ICI, 62 (53.9%) previously were treated with RS, 7(6.1%) RT and 46 (40%) no received RLT. ICI prescribed were atezolizumab (55.7%), pembrolizumab (16.5%), durvalumab (11.3%), durvalumab/tremelimumab (7.8%), nivolumab (5.2%) and avelumab (3.5%). The disease control rate (CR [6.9%] +PR [9.6%] +SD [14.1%]) was higher for pts with previous RLT compared to those pts who did not receive RLT (CR [3.2%] + PR [5.8%] + SD [6.4%](P=0.325). Median OS was 11.23 mo (95% CI; 6.02-16.44) and 7.95 mo (95%IC; 5.15-10.75) for group A and group B, respectively (P=0.481). Conclusions: This multicenter cohort suggests that previous RLT might play an impact for control disease in pts with mUC treated with ICI. Although this is hypothesis generating, the true value of this approach remains to be demonstrated in prospective studies.

Clinical activity of avapritinib in ≥ fourth-line (4L+) and PDGFRA Exon 18 gastrointestinal stromal tumors (GIST)

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Background: Targeting oncogenic KIT and PDGFRA mutations revolutionized treatment of patients (pts) with advanced GIST; however, nearly all pts succumb to resistant disease. Avapritinib is a potent and selective kinase inhibitor with broad activity against oncogenic KIT/PDGFRA mutants, including PDGFRA D842V and other primary or secondary resistance mutations. Results from the phase 1 NAVIGATOR (NCT02508532) study of avapritinib in pts with advanced GIST are presented. Methods: Adult pts with unresectable PDGFRA D842V or other mutant GIST who progressed on imatinib and ≥1 other tyrosine kinase inhibitor (TKI) were treated with oral, daily, continuous avapritinib. Adverse events (AE) and response by mRECIST 1.1 per central radiology were assessed. Overall population safety (30-600 mg starting doses) and efficacy in the response-evaluable 4L+ and PDGFRA Exon 18 (Ex 18) populations treated at the MTD (400 mg)/RP2D (300 mg) were analyzed. Results: As of 16 Nov 2018, 237 pts [172 KIT, 62 PDGFRA Ex 18 [56 D842V, 6 non-D842V), 2 PDGFRA N659K, 1 missing] were enrolled including 111 in the 4L+ population (primarily KIT, median 4 prior TKI) and 43 in the Ex 18 population (median 1 prior TKI). The 4L+ ORR was 22% [1 CR, 23 PR (1 pending)], and 52 SD with mDOR of 10.2 months (95% CI: 7.2–NE). The Ex 18 ORR was 86% [3 CR, 34 PR (1 pending)] and 5 SD; mDOR was not reached (95% CI: 11.3–NE). Most AEs were grade 1–2, most commonly nausea (63%), fatigue (58%), anemia (49%), periorbital edema (42%), diarrhea (40%), vomiting (40%), decreased appetite (38%), increased lacrimation (33%), peripheral edema (33%) and memory impairment (most common cognitive AE, 29%). 10% of pts discontinued due to a related AE. Grade 3–4 related AE ≥ 2% were anemia, fatigue, hypophosphatemia, hyperbilirubinemia, neutropenia, and diarrhea. Conclusions: Avapritinib has important clinical activity in pts with advanced GIST who have no effective therapies. The ORR and DOR of avapritinib in 4L+ exceeds that of approved 2nd and 3rd line therapies and shows impressive activity in D842V and other Ex 18 mutant PDGFRA GIST. Results suggest avapritinib has the potential to change the treatment paradigm of pts with advanced GIST. Clinical trial information: NCT02508532.

Clinical activity of avapritinib in ≥ fourth-line (4L+) and PDGFRA Exon 18 gastrointestinal stromal tumors (GIST)

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Background: Targeting oncogenic KIT and PDGFRA mutations revolutionized treatment of patients (pts) with advanced GIST; however, nearly all pts succumb to resistant disease. Avapritinib is a potent and selective kinase inhibitor with broad activity against oncogenic KIT/PDGFRA mutants, including PDGFRA D842V and other primary or secondary resistance mutations. Updated results from the phase 1 NAVIGATOR (NCT02508532) study of avapritinib in pts with advanced GIST are presented. Methods: Adult pts with unresectable PDGFRA D842V or other mutant GIST who progressed on imatinib and ≥ 1 other tyrosine kinase inhibitor (TKI) were treated with oral, daily, continuous avapritinib. Adverse events (AE) and response by mRECIST 1.1 per central radiology were assessed. Safety from the overall population (30-600 mg doses) and efficacy in the response evaluable 4L+ and PDGFRA Exon 18 (Ex 18) populations treated at the MTD (400 mg)/RP2D (300 mg) were analyzed. Results: As of 16 Nov 2018, 237 pts [172 KIT, 62 PDGFRA Ex 18 (56 D842V, 6 non-D842V), 2 PDGFRA N659K, 1 missing] were enrolled including 111 in the 4L+ population (primarily KIT, median 4 prior TKI) and 43 in the Ex 18 population (median 1 prior TKI). The 4L+ ORR was 22% [1 CR, 23 PR (1 pending)], and 52 SD with median duration of response (mDOR) of 10.2 months (95% CI: 7.2-NE). The Ex 18 ORR was 86% [3 CR, 34 PR (1 pending)] and 5 SD; mDOR was not reached (95% CI: 11.3-NE). Most AE were grade 1-2, most commonly nausea (63%), fatigue (58%), anemia (49%), periorbital edema (42%), diarrhea (40%), vomiting (40%), decreased appetite (38%), increased lacrimation (33%), peripheral edema (33%) and memory impairment (most common cognitive AE, 29%). 10% of pts discontinued due to a related AE. Grade 3-4 related AE ≥ 2% were anemia, fatigue, hypophosphatemia, hyperbilirubinemia, neutropenia, and diarrhea. Conclusions: Avapritinib has important clinical activity in pts with advanced GIST who have no effective therapies. The ORR and DOR of avapritinib in 4L+ exceeds that of approved 2nd and 3rd line therapies and shows unprecedented activity in D842V and other Ex 18 mutant PDGFRA GIST. Results suggest avapritinib has the potential to change the treatment paradigm of pts with advanced GIST. Clinical trial information: NCT02508532.

Translational study associated to a phase II study evaluating the activity of pazopanib in patients (pts) with advanced/metastatic liposarcoma (LPS): A joint Spanish Sarcoma Group (GEIS) and German Interdisciplinary Sarcoma Group (GISG) study

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Background: GEIS 30 was a phase II study showing moderate activity of pazopanib in well-differentiated/dedifferentiated LPS (cohort A:37 pts, Progression free Survival (PFS) at 12 weeks (w) 43.2%) and no activity in Myxoid/round cell LPS (cohort B: 15 pts, PFS at 12w 13.3%). The present study aims to identify tumor and plasma biomarkers that are differently expressed in long responders (LRs) PFS > 24 w. Methods: Serum samples and paraffin-blocks at diagnosis were collected for 28 pts in cohort A and 11 in B. A total of 13 pts were LRs. Serum samples were obtained at baseline, after 3 w of treatment and at progression. A panel of 15 cytokines and growth factors were evaluated using Luminex technology (Millipore). Paraffin-blocks were evaluated for microvessel density (MVD) by CD31 immunostaining and Image Pro-Plus 7.0 Image Analysis System (Media-Cybernetics). For RNA expression analysis, the Oncology Biomarker Panel with probes for 2559 transcripts was used (HTG Molecular Diagnostics). Results: Serum cytokines showed that expression of angiopoietin (AGO) and BMP9 decreases during treatment, whereas GCSF increases. In addition, AGO and BMP overexpression at baseline was associated with worse prognosis in arm A (p = 0.09) and B (p = 0.01) respectively. No differences between study arms and outcome were appreciated by MVD. Gene expression revealed differences in some immunomodulators: PDL-1 was correlated with serum cytokines VEGFD (p = 0.04) and LEPTIN (p = 0.02); and PD-1 with VEGFD (p = 0.04), LEPTIN (p = 0.02), VEGFA (p = 0.02) and ANGIO (p = 0.03). PD1, in addition,was overexpressed in LRs (p = 0.05). Interestingly, three groups were identified in cohort A according to gene expression: Cluster 1, characterized by short-responder patients with the shortest overall survival, whereas cluster 3 (40% LRs) and 2 (63.6% LRs) showed longer survival rates (14.3%, 45.5% and 30% respectively) (p = 0.001). Conclusions: Gene expression profiling unveils three WD/DD-LPS biotypes according to their response to pazopanib, which could be potentially used to select pts for treatment

Impact of immune-related adverse events on survival in patients with metastastic urothelial carcinoma treated with immune-checkpoint inhibitors

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Background: Immune-checkpoints inhibitors (ICIs) represents the standard of care for platinum-pretreated advanced urothelial cancer patients (pts). By enhancing T-cell activation, a unique spectrum of inflammatory side effects has emerged, also known as immune-related adverse events (irAEs). Data regarding the association between irAEs and pts outcomes are conflicting. Here we conducted a retrospective analysis to investigate the association between irAEs profile and disease outcome in metastastic urothelial carcinoma (mUC) pts. Methods: Medical records from pts with mUC included in clinical trials between July 2013 and June 2018 and treated with ICIs were reviewed. Pts previously treated with platinum-based chemotherapy or cisplatin ineligible pts who had not been previously treated with chemotherapy were included. Clinical responses were assessed as complete response (CR), partial response (PR), stable disease (SD), and progressive disease (PD) according to RECIST v1.1. Adverse events were graded based CTCAE v4.03. Overall survival (OS) was calculated from the date of initiation of ICI to the date of death. X2 test was used to determine differences in rates. OS was estimated using Kaplan-Method and long rank test was used to assess differences between groups. All analyses were performed using SPSS v21. Results: From a total of 52 pts, 44 (84.6%) were treated with ICI monotherapy and 8 (15.3%) in combination (anti-CTLA4 or targeted therapy). Median age was 65 years, 42 pts (80.8%) were male, 44 patients (84.6%) had ECOG PS 0-1, 14 pts (26.9%) had liver metastasis. Overall irAEs were observed in 30 pts (57.7%) and 10 pts (19.2%) developed grade 3/4 irAES. Most common grade 3/4 irAEs were diarrhea (6.6%), rash (6.6%) and hepatitis (6.6%). Disease control rate (CR [26%]+PR[33%]+SD[20%]) was higher for patients with irAEs compared to those patients who did not developed irAEs (CR [13.6%]+PR[0%]+SD[22.7%], this difference was statically significant (P = 0.002). Median OS was 11.23 mo (CI 95%, 3.76-18.70) for the overall cohort, while median OS was 21.91 mo for those patients with irAEs compared to 6.47 mo in patients who did not developed irAEs (P = 0.004). Conclusions: In this analysis we found that the development of irAEs was a strong predictor of improved OS in mUC patients treated with ICI.

Hyperprogressive disease in patients with metastatic genitourinary tumors treated with immune checkpoint inhibitors

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Background: Hyperprogressive disease (HPD) is a new pattern of progression in cancer patients (pts) treated with immune checkpoint inhibitors (ICI). The rate and outcome of HDP in pts with metastatic renal carcinoma (RCC) and urothelial carcinoma (UC) are unknown. Here, we report the percentage of HPD in a cohort of pts with GU malignancies treated at our center and explore associations with clinical variables. Methods: Medical records from pts treated in phase I-III clinical trials with ICI alone or in combination between July 2013 and June 2018 were retrospectively reviewed. We defined HPD according to the radiologic VHIO´s criteria (ASCO 2018). Associations between HPD and categorical or continuous variables were evaluated using Fisher exact test and Wilcoxon test respectively. OS were estimated with the Kaplan-Meir method. Statistical analyses were performed using the R statistical software (R version 3.5.0). Results: Overall, 104 pts received therapy with ICI. Of these patients, 16 were not included for the analysis (6 pts with absence of measurable disease, 6 pts did not have CT scan available after the clinical progression and 4 pts treated with ICI plus chemotherapy). Thus, 88 pts were included for the analysis, 29 (33%) with RCC and 59 (67%) with UC. Median follow-up was 7.4 months. Median age was 66.5 years (range 29-91 y).Twenty-three pts (26%) were treated with ICI monotherapy and 65 pts (74%) in combination (anti-CTL4, antiangiogenics, PARP inhibitors, FGFR inhibitors). Forty-seven pts (53%) received ICI as second-line therapy or later. By RECIST v1.1, 26 (30%), 19 (21%) and 43(49%) pts had a best response of progressive disease, stable disease or partial+complete response, respectively. We identified 9 pts (10%) who meet the HPD criteria, 2 pts with RCC and 7 with UC. HPD was associated with anemia at baseline (p = 0.058). Pts with HPD had a trend toward lower overall survival (OS) compared with pts with non-HPD (8.87 vs 4.77 months; p = 0.065). Conclusions: These findings demonstrate that HPD is a phenomenon seen in a significant proportion of pts with RCC and UC and should be taken in account. We found that HPD is associated with poor OS and the anemia at baseline was correlated with HPD.

PEEK Implant: A Case Report Illustrating the Benefits for Correcting Craniosynostosis Asymmetry

BACKGROUND

Unilateral coronal synostosis can cause aesthetically unappealing plagiocephaly, which often requires surgical correction. The techniques utilized for this operation have continued to evolve. Unfortunately, some patients who have fronto-orbital advancement will have residual asymmetry.

CASE

We present a case of a 21 year-old female with residual asymmetry who was suffering from facial swelling and refractory trigeminal neuralgia. It was decided to perform an additional surgery with polytheretheketone (PEEK) implant to restore normal symmetry and provide symptomatic relief.

CONCLUSION

The ideal fit PEEK implant provided excellent cosmetic results and the operation relieved her symptoms. We provide a detailed discussion on why PEEK implants are great options for these types of cases due to advanced pre-surgical planning technology, ease of placement, and durability over time.

Growing Skull Fracture: Case Report after Rottweiler Bite and Review of the Literature

Growing skull fracture remains a rare but clinically significant complication of traumatic skull fractures in children less than 3 years of age. Dog attacks on children commonly cause head and neck injuries. We report the first case of growing skull fracture caused by a Rottweiler bite in a 21 days old neonate. Early diagnosis and surgical repair resulted in excellent outcome.

Gene expression analyses determine two different subpopulations in KIT-negative GIST-like (KNGL) patients

Introduction

There are limited findings available on KIT-negative GIST-like (KNGL) population. Also, KIT expression may be post-transcriptionally regulated by miRNA221 and miRNA222. Hence, the aim of this study is to characterize KNGL population, by differential gene expression, and to analyze miRNA221/222 expression and their prognostic value in KNGL patients.

Methods

KIT, PDGFRA, DOG1, IGF1R, MIR221 and MIR222 expression levels were determined by qRT-PCR. We also analyzed KIT and PDGFRA mutations, DOG1 expression, by immunohistochemistry, along with clinical and pathological data. Disease-free survival (DFS) and overall survival (OS) differences were calculated using Log-rank test.

Results

Hierarchical cluster analyses from gene expression data identified two groups: group I had KIT, DOG1 and PDGFRA overexpression and IGF1R underexpression and group II had overexpression of IGF1R and low expression of KIT, DOG1 and PDGFRA. Group II had a significant worse OS (p = 0.013) in all the series, and showed a tendency for worse OS (p = 0.11), when analyzed only the localized cases. MiRNA222 expression was significantly lower in a control subset of KIT-positive GIST (p < 0.001). OS was significantly worse in KNGL cases with higher expression of MIR221 (p = 0.028) or MIR222 (p = 0.014).

Conclusions

We identified two distinct KNGL subsets, with a different prognostic value. Increased levels of miRNA221/222, which are associated with worse OS, could explain the absence of KIT protein expression of most KNGL tumors.

Functional gastrointestinal disorders in children from low socio-economic status and Helicobacter pylori infection

BACKGROUND

Most studies on functional gastrointestinal disorders (FGIDs) in children are based on data from the northern hemisphere. Scientific reports are arising in South American population, but little is still known about children from low socio-economic status (SES), where Helicobacter pylori infection is endemic. Our objective was to evaluate the prevalence of FGIDs in school children from low SES and its relationship with H. pylori infection.

METHODS

Children from 3 public schools of low SES from Santiago de Chile were included. Students completed the Rome III Questionnaire and a survey about other symptoms. Also, the ¹³ C urea breath test determined the presence of H. pylori infection.

RESULTS

Five hundred six children were included, where 48% were male, with a median age of 15.7 years (range 7.1-19.6). Forty-two percent had some FGID, aerophagia and functional constipation being the most frequent. Females (adjusted OR 1.5, 95% CI [1.1, 2.2]), those children with parents within the lowest level of education (adjusted OR 1.6, 95% CI: 1.1-2.4), and family history of gastric cancer (adjusted OR 1.9, 95% CI: 1.2-3.1) were related to FGIDs. The prevalence of H. pylori infection was 55.9% (95% CI [50.7, 60.9]). In multivariable analysis, the presence of abdominal pain (OR 1.55, 95% CI [1.02, 2.36]), but not FGIDs, was related to H. pylori infection.

CONCLUSIONS

FGIDs are common in low SES students. A low educational level of the household head, family history of gastric cancer. and being female are related to the development of FGIDs. In this study, no relationship between the presence of H. pylori and FGIDs was found.