Gastrointestinal Stromal Tumors Research Articles

Prognostic nomogram in patients with gastrointestinal stromal tumors: a SEER-based study.

Gastrointestinal stromal tumor (GIST) is a common mesenchymal tumor of the gastrointestinal system. They originate from the interstitial cells of Cajal located within the muscle layer and are characterized by over-expression of the tyrosine kinase receptor KIT. Data from the Surveillance Epidemiology, and End Results (SEER) database of 1,213 patients diagnosed with GIST between 2010 and 2019 were dichotomized into a modeling set and a validation set at a 2:1 ratio. For the modeling set, both univariate and multivariate Cox regression analyses were used to identify independent prognostic factors. A nomogram was then constructed based on these determinants. Model efficacy was tested using receiver operating characteristic (ROC) curves, calibration curves, clinical decision curves, and risk stratification analysis in both subsets. Identified prognostic determinants included age, sex, pathological differentiation level, tumor-node-metastasis (TNM) stage, surgical intervention, radiotherapy, and marital status. The constructed nomogram showed area under the ROC curve (AUC) values of 0.822, 0.793, and 0.779 for 1-, 3-, and 5-year overall survival (OS) in the modeling set, respectively, while in the validation set, the values were 0.796, 0.823, and 0.806, respectively. Calibration plots from both sets confirmed the concordance between predicted and observed survival. Decision curve analysis (DCA) indicated significant clinical utility for the nomogram. Risk stratification of the patient data revealed distinct survival differences between high-risk and low-risk cohorts in both sets (P<0.001). A novel and potent nomogram for the prognosis of GIST has been introduced. This model's precision offers crucial insights for clinical decisions, yet further external validation remains essential.

Multiple Gastrointestinal Stromal Tumors, Malignant Peripheral Nerve Sheath Tumor and Atypical Neurofibromatous Neoplasm With Uncertain Biologic Potential Developing in A Single Patient With Neurofibromatosis Type 1 Syndrome.

Neurofibromatosis type 1 (NF1) is the most common human genetic disease. In these patients, the incidence of malignant peripheral nerve sheath tumors (MPNST) and gastrointestinal stromal tumors (GIST) is increased. A male patient in his forties with neurofibromatosis 1, presented with the coexistence of multiple GISTs located at intestinal and colonic mesentery, MPNST located at his leg and atypical neurofibromatous neoplasm with uncertain biologic potential located at colonic mesentery. By FISH, the MPNST harbored CDKN2A loss and recurred 1 year later. After reresection and radiotherapy, the patient is now disease-free without evidence of disease. Atypical neurofibromatous neoplasm with uncertain biologic potential is a newly defined entity, and it is important to discriminate it from low-grade MPNST, which requires more aggressive treatment methods. To the best of our knowledge, this is the first report describing synchronous GISTs, MPNST, and atypical neurofibromatous neoplasm with uncertain biologic potential developing in a single NF1 patient.

Glycaemic abnormalities induced by small molecule tryosine kinase inhibitors: a review.

In light of the expected increase in the prevalence of diabetes mellitus due to an aging population, sedentary lifestyles, an increase in obesity, and unhealthy diets, there is a need to identify potential pharmacological agents that can heighten the risk of developing diabetes. Similarly, it is equally important to also identify those agents that show blood glucose-lowering properties. Amongst these agents are tyrosine kinase inhibitors used to treat certain types of cancers. Over the last two decades, there has been an increase in the use of targeted chemotherapy for cancers such as renal cell carcinoma, chronic leukaemia, and gastrointestinal stromal tumours. Small molecule tyrosine kinase inhibitors have been at the forefront of targeted chemotherapy. Studies have shown that small molecule tyrosine kinase inhibitors can alter glycaemic control and glucose metabolism, with some demonstrating hypoglycaemic activities whilst others showing hyperglycaemic properties. The mechanism by which small molecule tyrosine kinase inhibitors cause glycaemic dysregulation is not well understood, therefore, the clinical significance of these chemotherapeutic agents on glucose handling is also poorly documented. In this review, the effort is directed at mapping mechanistic insights into the effect of various small molecule tyrosine kinase inhibitors on glycaemic dysregulation envisaged to provide a deeper understanding of these chemotherapeutic agents on glucose metabolism. Small molecule tyrosine kinase inhibitors may elicit these observed glycaemic effects through preservation of β-cell function, improving insulin sensitivity and insulin secretion. These compounds bind to a spectrum of receptors and proteins implicated in glucose regulation for example, non-receptor tyrosine kinase SRC and ABL. Then receptor tyrosine kinase EGFR, PDGFR, and FGFR.

Otros tumores gástricos: tumores del estroma gastrointestinal; tumores neuroendocrinos y linfoma gástrico

Although the most common stomach cancer is adenocarcinoma, there are other types of stomach cancers such as gastrointestinal stromal tumors (GIST), neuroendocrine tumors, and gastric lymphoma. Their onset has been linked to environmental factors. They usually progress asymptomatically until locally advanced stages, when they can give rise to a wide variety of symptoms. Upper gastrointestinal endoscopy with biopsy collection is the diagnostic method of choice. Other techniques such as echoendoscopy, computed tomography, or magnetic resonance imaging are used for staging. There are a variety of treatments ranging from endoscopic, such as mucosectomy or submucosal dissection, to surgical to systemic treatments.

Pan-Cancer Interrogation of MUTYH Variants Reveals Biallelic Inactivation and Defective Base Excision Repair Across a Spectrum of Solid Tumors.

Biallelic germline pathogenic variants of the base excision repair (BER) pathway gene MUTYH predispose to colorectal cancer (CRC) and other cancers. The possible association of heterozygous variants with broader cancer susceptibility remains uncertain. This study investigated the prevalence and consequences of pathogenic MUTYH variants and MUTYH loss of heterozygosity (LOH) in a large pan-cancer analysis. Data from 354,366 solid tumor biopsies that were sequenced as part of routine clinical care were analyzed using a validated algorithm to distinguish germline from somatic MUTYH variants. Biallelic germline pathogenic MUTYH variants were identified in 119 tissue biopsies. Most were CRCs and showed increased tumor mutational burden (TMB) and a mutational signature consistent with defective BER (COSMIC Signature SBS18). Germline heterozygous pathogenic variants were identified in 5,991 biopsies and their prevalence was modestly elevated in some cancer types. About 12% of these cancers (738 samples: including adrenal gland cancers, pancreatic islet cell tumors, nonglioma CNS tumors, GI stromal tumors, and thyroid cancers) showed somatic LOH for MUTYH, higher rates of chromosome 1p loss (where MUTYH is located), elevated genomic LOH, and higher COSMIC SBS18 signature scores, consistent with BER deficiency. This analysis of MUTYH alterations in a large set of solid cancers suggests that in addition to the established role of biallelic pathogenic MUTYH variants in cancer predisposition, a broader range of cancers may possibly arise in MUTYH heterozygotes via a mechanism involving somatic LOH at the MUTYH locus and defective BER. However, the effect is modest and requires confirmation in additional studies before being clinically actionable.

Neoadjuvant imatinib in locally advanced gastrointestinal stromal tumors (GIST) is effective and safe: results from a prospective single center study with 108 patients

Neoadjuvant imatinib in locally advanced gastrointestinal stromal tumors (GIST) is effective and safe: results from a prospective single center study with 108 patients

Development and validation of a computed tomography-based radiomics signature to predict "highest-risk" from patients with high-risk gastrointestinal stromal tumor.

Some patients with high-risk gastrointestinal stromal tumor (GIST) experience disease progression after complete resection and adjuvant therapy. It is of great significance to distinguish these patients among those with high-risk GIST. Radiomics has been demonstrated as a promising tool to predict various tumors prognosis. From January 2006 to December 2018, a total of 100 high-risk GIST patients (training cohort: 60; validation cohort: 40) from Guangdong Provincial People's Hospital with preoperative enhanced computed tomography (CT) images were enrolled. The radiomics features were extracted and a risk score was built using least absolute shrinkage and selection operator-Cox model. The clinicopathological factors were analyzed and a nomogram was established with and without radiomics risk score. The concordance index (C-index), calibration plot, and decision curve analysis (DCA) were used to evaluate the performance of the radiomics nomograms. We selected 11 radiomics features associated with recurrence or metastasis. The risk score was calculated and significantly associated with disease-free survival (DFS) in both the training and validation group. Cox regression analysis showed that Ki67 was an independent risk factor for DFS [P=0.004, hazard ratio 4.615, 95% confidence interval (CI): 1.624-13.114]. The combined radiomics nomogram, which integrated the radiomics risk score and significant clinicopathological factors, showed good performance in predicting DFS, with a C-index of 0.832 (95% CI: 0.761-0.903), which was better than the clinical nomogram (C-index 0.769, 95% CI: 0.679-0.859) in training cohort. The calibration curves and the DCA plot suggested satisfying accuracy and clinical utility of the model. The CT-based radiomics nomogram, combined with the clinicopathological factors and risk score, has good potential to assess the recurrence or metastasis of patients with high-risk GIST.

Evaluation of surgical outcomes following gastric gastrointestinal stromal tumor (GIST) resections in the first thirteen years of the Dutch GIST registry

Evaluation of surgical outcomes following gastric gastrointestinal stromal tumor (GIST) resections in the first thirteen years of the Dutch GIST registry

Radiofrequency ablation vs. hepatectomy for liver metastases from gastrointestinal stromal tumors.

For patients with gastrointestinal stromal tumors (GISTs) and liver metastases, there is still debate about whether radiofrequency ablation (RFA) or hepatectomy is preferable. The present study aimed to compare the clinical outcomes of RFA with hepatectomy in patients with GISTs and liver metastases. The present retrospective study consisted of a cohort of 43 patients who had been diagnosed with liver metastases from GISTs between January 2010 and December 2022. The study included 18 patients who received RFA combined with tyrosine kinase inhibitor (TKI) therapy (RFA group) and 25 patients who underwent hepatectomy combined with TKI therapy (hepatectomy group). For the patients with liver metastases, the progression-free survival (PFS) rates at 1, 3 and 5 years were 66.5, 38.2 and 33.9%, respectively. Notably, patients in the hepatectomy group exhibited significantly improved PFS times compared with those in the RFA group (median PFS, 42.7 months vs. 14.3 months; P=0.034). Furthermore, the time to imatinib treatment failure (TTF) was notably improved in the hepatectomy group compared with that in the RFA group, and this difference was statistically significant (median TTF, 71.1 vs. 38.0 months; P=0.041). However, the overall survival (OS) times of patients who received RFA and those who had hepatectomy did not differ significantly (median OS, not reached vs. not reached, P=0.120). There was no statistically significant distinction in PFS and TTF between patients who underwent hepatectomy combined with postoperative TKI and those who underwent hepatectomy combined with perioperative TKI (median PFS, 29.5 vs. not reached; P=0.520; median TTF, 66.4 months vs. 71.1 months; P=0.430). The univariate and multivariate analyses consistently identified the sole prognostic factor affecting PFS as hepatectomy combined with TKI therapy (hazard ratio, 0.379; 95% CI, 0.159-0.899; P=0.028). In conclusion, hepatectomy combined with TKI therapy improved prognosis for patients with liver metastases to a greater extent than RFA combined with TKI therapy. For this type of patient, hepatectomy may be a preferable option.

Sclerosing angiomatoid nodular transformation of spleen with calcifying fibrous pseudotumor: A rare case with unusual association

Sclerosing angiomatoid nodular transformation (SANT) of the spleen is a rare benign vascular lesion of the spleen that was first described in 2004. SANT is associated with other concurrent diseases, mostly malignancies. Calcifying fibrous pseudotumor (CFPT) is a tumor-like lesion usually arising from soft tissue or peritoneal sub-serosa. Both SANT and CFPT are considered to be variants of the inflammatory myofibroblastic tumor. We report the rare case of a 24-year-old female presenting with a left abdominal mass that was clinically diagnosed as an extraintestinal gastrointestinal stromal tumor (GIST). Histopathological examination revealed SANT of spleen and CFPT. We report this case due to its rarity of occurrence and unusual association of SANT with CFPT.

PERITONEAL TUBERCULOSIS MIMIKING GASTROINTESTINAL STROMAL TUMOR

Abdominal TB is a common site of extrapulmonary tubercilosis, and peritoneal tuberculosis (PTB) is one of the most common manifestations of abdominal tuberculosis. The diagnosis of PTB can be made based on a combination of clinical, radiological, histological, and laboratory tests. The diagnosis can be easy in the presence of ascites with peritoneal granulations. some forms of PTB can make a differential diagnosis with peritoneal or digestive tract pathologies. some forms of PTB can make a differential diagnosis with peritoneal or digestive tract pathologies. We report a case of primary mesenteric tuberculosis mimicking gastrointestinal stromal tumor. The final diagnostic was performed using a combination of invasive and imaging techniques.

A rare case presentation of neurofibromatosis type 1 with multiple gastrointestinal stromal tumors: a case report

Neurofibromatosis type 1 (NF1), a hereditary cancer predisposing syndrome is an autosomal dominant disorder. Gastrointestinal stromal tumor (GIST) is the most prevalent non-neurological tumor in these individuals. In NF1-associated GIST, KIT and platelet-derived growth factor receptor α (PDGFRA) mutations might not be present, and Imatinib may not be effective. Surgical resection is the first-line treatment. The primary aim was to include the possibility of rare tumors including GIST in neurofibromatosis patients in the differential diagnosis of GIT pathology/presentation. A 50-year-old male with neurofibromatosis came with complaints of dull aching abdominal pain and on further investigation was found to have lesions in the distal small bowel, suspicious of nerve sheath tumors, in abdominal computed tomography. A laparotomy was performed and the jejunum containing nodular lesions was resected and pathologically diagnosed as GIST. The patient was then started on Imatinib. At the 6-month follow-up, no tumor recurrence was visible. The rare and unusual location of multiple GIST in neurofibromatosis patients underscores its importance in differential diagnosis, and our case report on the patient's therapy and the clinical outcome could aid in patient care.

Duodenal neuroendocrine tumor after bilateral breast cancer with type 1 neurofibromatosis: a case report

BackgroundYoung women with NF1 are at a high risk of developing breast cancer. Although they are at risk for abdominal tumors, such as gastrointestinal stromal tumors and neuroendocrine tumors, follow-up strategies for other tumors after breast cancer have not yet been established. Here, we present a case of duodenal neuroendocrine tumor found during follow-up after bilateral mastectomy for breast cancer with type 1 neurofibromatosis (NF1), for which pancreaticoduodenectomy (PD) and lymphadenectomy were performed.Case presentationA 46-year-old woman with NF1 was referred to our hospital for treatment of a duodenal submucosal tumor. Her previous operative history included bilateral mastectomy for breast cancer: right total mastectomy and left partial mastectomy performed 9 and 5 years ago, respectively. Her daughter was confirmed to have NF1, but her parents were unclear. Although she had no recurrence or symptoms during the follow-up for her breast cancer, she wished to undergo 18-fluorodeoxyglucose–positron emission tomography (FDG–PET) for systemic screening. FDG–PET demonstrated FDG accumulation in the duodenal tumor with a maximum standardized uptake value of 5.78. Endoscopy revealed a 20-mm-diameter tumor in the second duodenal portion, and endoscopic biopsy suggested a NET G1. We performed PD and lymphadenectomy for complete. She was doing well without recurrence and was followed up with PET tomography–computed tomography.ConclusionsEarly detection of gastrointestinal tumors is difficult, because most of them are asymptomatic. Gastrointestinal screening is important for patients with NF1, and PD with lymphadenectomy is feasible for managing duodenal neuroendocrine tumors, depending on their size.

Ultrasensitive detection of imatinib in human serum using a gold-based paper sensor

Imatinib is the tyrosine kinase inhibitor of choice for the treatment of chronic myeloid leukemia and gastrointestinal stromal tumors. However, imatinib has drawbacks such as drug resistance and significant differences in pharmacokinetics within patients. Therefore, a colloidal gold-based immunochromatographic assay (CG-IA) was developed for measuring and monitoring imatinib in human serum. An imatinib derivative containing carboxyl groups was used for the synthesis of the immunogen, and 4-(4-methyl-1-piperazinylmethyl) benzoic acid was selected as the hapten for the heterologous coating antigen. Next, a highly sensitive and specific monoclonal antibody (mAb), 2F7 was screened for the construction of a CG-IA, with an IC50 value of 0.091 ng/mL. For the qualification of imatinib in human serum, the visual limit of detection (vLOD) and cut-off values of the CG-IA were 2 and 20 ng/mL, respectively. For quantitative detection, the calculated LOD value of the CG-IA was 0.068 ng/mL, with a linearity range of 1.004 and 23.087 ng/mL. The recovery rate of spiked serum samples was between 88.24 % and 104.75 %. In addition, the concentration of imatinib in the serum samples from 10 patients was detected by CG-IA and revealed a good correlation with those from LC-MS/MS. These results indicated that the developed gold-based paper sensor could become an effective tool for the rapid monitoring of imatinib in human serum samples.

Prognostic factors for liver metastasis in patients with small intestinal stromal tumor: A retrospective analysis of surveillance, epidemiology, and end results.

Liver metastasis (LIM) is the most common distant site of metastasis in small intestinal stromal tumors (SISTs). The aim of this study was to determine the risk and prognostic factors associated with LIM in patients with SISTs. Patients diagnosed with gastrointestinal stromal tumors between 2010 and 2019 were selected from the Surveillance, Epidemiology, and End Results (SEER) database. Univariate and multivariate logistic regression models, as well as a Cox regression model were used to explore the risk factors associated with the development and prognosis of LIM. Additionally, the overall survival (OS) of patients with LIM was analyzed using the Kaplan-Meier method. Furthermore, a predictive nomogram was constructed, and the model's performance was evaluated using receiver operating characteristic (ROC) curve, calibration curve, and decision curve analysis (DCA). A total of 1582 eligible patients with SISTs were included, among whom 146 (9.2%) were diagnosed with LIM. Poor tumor grade, absence of surgery, later T-stage, and no chemotherapy were associated with an increased risk of developing LIM. The nomogram prediction model achieved an AUC of 0.810, 95% Confidence Interval (CI) 0.773-0.846, indicating good performance, and the calibration curve showed excellent accuracy in predicting LIM. The OS rate of patients with LIM was significantly lower than that of patients without LIM (p<0.001). Patients with SISTs who are at high risk of developing LIM deserve more attention during follow-up, as LIM can significantly affect patient prognosis. The nomogram demonstrated good calibration and discrimination for predicting LIM.

Is lymph node metastasis an event indicating an advanced gastrointestinal stromal tumor?

754 Background: The clinicopathological features and prognosis of gastrointestinal stromal tumors (GISTs) with lymph node metastasis remain controversial owing to their low incidence. A multicenter retrospective cohort study was conducted to compare the clinicopathological features and oncologic outcomes of GIST with and without lymph node metastases. Methods: The medical records of patients with GISTs in 16 large medical centers in China from January 2014 to December 2020 were reviewed. Patients were divided into three groups: no metastasis, lymph node metastasis without distant metastasis, and distant metastasis without lymph node metastasis. Propensity score matching (PSM) was performed to reduce confounding factors. Results: A total of 1109 cases of primary GIST were included in this study, comprising 607 males (54.7%) and 502 females (45.3%), with a mean age of 56.6±11.9 years. There were 1024 patients (92.3%) with no lymph node metastasis after surgery, and 85 patients (7.7%) had lymph node metastasis. Compared to that in GIST without lymph node metastasis, the proportion of non-gastric GIST was higher in GIST with lymph node metastasis (52.9% vs. 40.7%) with a larger tumor diameter (&gt;10 cm: 36.5% vs. 18.1%) and more patients with distant metastasis (11.8% vs. 3.5%). Tumor location not in the stomach, the largest tumor diameter, and distant metastasis were independent risk factors for GIST with lymph node metastasis (all P &lt; 0.05). After PSM, 96, 48, 24 patients comprised no metastasis, lymph node metastasis without distant metastasis, and distant metastasis without lymph node metastasis, respectively. The relapse-free survival (RFS) of the lymph node metastasis group was comparable to that of the distant metastasis group without lymph node metastasis ( P = 0.368) and significantly inferior to that of no metastases ( P = 0.042). Conclusions: The prognosis of patients with GIST with lymph node metastasis was comparable to that of patients with distant metastasis and significantly worse than that of patients without metastasis. Lymph node metastasis may be an advanced event in GIST.

Characteristics and predictors of outcomes with neoadjuvant imatinib in gastrointestinal stromal tumors: Real-world data from a large patient registry.

737 Background: The standard of care for patients with moderate or high-risk resectable gastrointestinal stromal tumors (GIST) is surgical resection followed by adjuvant therapy with imatinib. The impact of neoadjuvant imatinib on long-term outcomes is largely unknown. Methods: We interrogated the LifeRaft registry, a large international open cohort of patients with GIST. We included patients who did not have metastatic disease at diagnosis, underwent surgical resection and received neoadjuvant imatinib and had no recorded mutations of Kit exon 13 or PDGFRA exon 18 D842V. Baseline patient characteristics were described and survival probabilities were estimated and plotted using the Kaplan-Meier method. Cox regression was used to estimate the effect of demographic and clinical characteristics on recurrence-free survival (RFS) and overall survival (OS). For RFS, time was calculated from the date of surgery to disease recurrence/death, whichever came first. For OS, time was calculated from the date of surgery to death. Estimated effects of predictors were reported as hazard ratios (HR) along with 95% confidence intervals (CI). All statistical testing was two-sided and assessed for significance at the 5% level using SAS v9.4 (SAS Institute, Cary, NC). Results: Out 2,472 patients with GIST, 137 patients met the inclusion criteria and received neoadjuvant imatinib for a median of 6.8 months. Majority of the patients were aged 40 years or above (129/137, 94.2%) and were males (73/137, 53.3%). The majority of the patients had gastric GIST (72/137, 54.1%), followed by small intestine GIST (34/137, 25.6%) and other (27/137, 20.3%). Most patients had a tumor size of &gt;10 cm (66/137, 52.4%) at the time of diagnosis followed by &gt;5 cm - &lt;=10 cm (42/137, 33.3%) and &gt;2 cm - &lt;=5 cm (18/137, 14.3%). The median RFS for the cohort was 6.1 years. On multivariable analysis, tumor size (HR 1.08, 95% CI 1.05-1.12, p&lt;0.01) and the overall duration of treatment (neoadjuvant and adjuvant) with imatinib therapy (HR 0.98, 95% CI 0.97-0.99, p&lt;0.01) were significantly associated with RFS. A 1-cm increase in tumor size and 1-month increase in total time on imatinib was associated with an 8% increase and 2% decrease in risk of recurrence. The median OS was 14.2 years. Female gender (HR 0.23 95% CI 0.08-0.65, p&lt;0.01) and total length of time on imatinib (HR 0.97 95% CI 0.96-0.99, p&lt;0.01) were found to be significantly associated with OS. Female patients were associated with a 77% decreased risk of death and a 1-month increase in the total time on imatinib was associated with a 3% decrease in the risk of death. Conclusions: We show that most patients receiving neoadjuvant imatinib have gastric GIST with tumor size &gt;10 cm. Smaller tumor size and female gender predicted longer RFS and OS respectively. Longer total duration of imatinib therapy was associated with increased RFS and OS.

INSIGHT: A phase 3, randomized, open-label study of ripretinib vs sunitinib in patients with advanced gastrointestinal stromal tumor previously treated with imatinib with KIT exon 11 + 17/18 mutations.

TPS767 Background: Gastrointestinal stromal tumor (GIST) is the most common gastrointestinal sarcoma with approximately 80% of cases driven by KIT mutations. Most patients (pts) with advanced GIST experience disease progression following first-line treatment with imatinib due to KIT secondary resistance mutations occurring most commonly in the ATP-binding pocket (exons 13/14) and/or activation loop (exons 17/18). Sunitinib is approved as second-line therapy for advanced GIST. Ripretinib is a switch-control tyrosine kinase inhibitor approved for pts with GIST who received prior treatment with 3 or more kinase inhibitors, including imatinib. In the phase 3 INTRIGUE study (NCT03673501) in second-line advanced GIST, ripretinib was not superior to sunitinib in terms of progression-free survival (PFS); however, a more favorable safety profile was observed with ripretinib vs sunitinib.1 Exploratory mutational analysis from INTRIGUE using baseline circulating tumor DNA (ctDNA) demonstrated that pts harboring primary KIT exon 11 mutations with secondary resistance mutations exclusively in KIT exons 17/18 derived PFS benefit with ripretinib vs sunitinib (median, 14.2 vs 1.5 months; HR, 0.22; 95% CI, 0.11 to 0.44; nominal P &lt;0.0001).2 Here, we describe a planned phase 3 study for pts with advanced GIST previously treated with imatinib harboring KIT exon 11 + 17/18 mutations. Methods: INSIGHT (NCT05734105) is a phase 3, randomized, open-label study aiming to evaluate the efficacy of ripretinib vs sunitinib in pts with advanced GIST previously treated with imatinib and who harbor KIT exon 11 + 17/18 mutations. Eligible pts must be ≥18 years old with histologically confirmed GIST and co-occurring KIT exon 11 + 17/18 mutations confirmed by ctDNA analysis. Pts must also have advanced disease with ≥1 measurable lesion per modified Response Evaluation Criteria in Solid Tumors (mRECIST) v1.1, radiologic progression on imatinib, and an Eastern Cooperative Oncology Group performance status ≤2. Key exclusion criteria include a KIT exon 9, 13, or 14 mutation confirmed via ctDNA analysis at screening and prior treatment with another line of therapy in addition to imatinib for advanced GIST. A total of 54 pts will be randomized (2:1) to receive ripretinib 150 mg once daily (QD; continuous) or sunitinib 50 mg QD (4 weeks on/2 weeks off) in 6-week cycles. The primary endpoint is PFS by independent radiologic review (IRR) per mRECIST v1.1; key secondary endpoints are objective response rate by IRR using mRECIST v1.1 and overall survival. Safety and patient-reported outcome measures will also be assessed. Pts randomized to the sunitinib arm may cross over to the ripretinib arm upon disease progression. 1. Bauer S et al. J Clin Oncol. 2022. 2. Bauer S et al. J Clin Oncol. 2023; abstract 397784. Clinical trial information: NCT05734105 .

Real-world analysis of patients with advanced gastrointestinal (GI) cancers harboring inactivating TSC1 and TSC2 alterations using the Foundation Medicine genomic database.

558 Background: Genomic profiling of GI tumors can identify potentially actionable genetic alterations, ultimately leading to better outcomes in patients who currently have few treatment options. In exploratory biomarker analyses of patients with perivascular epithelioid cell tumors treated with the mTOR inhibitor nab-sirolimus (AMPECT, NCT02494570), those with inactivating alterations in the tumor suppressor genes TSC1 or TSC2 (critical negative regulators of mTOR activity) had confirmed responses (8/9 patients with inactivating TSC2 alterations and 1/5 patients with inactivating TSC1 alterations). PRECISION 1, a currently enrolling tumor-agnostic study, will evaluate nab-sirolimus in patients with TSC1 or TSC2 alterations. To enumerate the frequency of these alterations in GI cancers, we analyzed data from a real-world genomic database. Methods: Next-generation sequencing (NGS) data from Foundation Medicine’s genomic database of patients with advanced cancer were analyzed using the FoundationInsights web-based platform to identify patients with GI cancers who had inactivating TSC1 or TSC2 alterations (short variants [base substitutions, insertions and deletions], rearrangements, and copy number deletions). Tumor mutational burden (TMB), microsatellite instability status and other mutations were also characterized in this group of patients. Results: As of 29 March 2022, tumor tissue NGS data were available for 5816 patients with GI cancers bearing alterations in TSC1 or TSC2. Of these, 1642 patients had at least one inactivating alteration. The GI tumor types that most frequently expressed inactivating alterations in TSC1 or TSC2 were hepatocellular carcinoma (alterations in 6.5%); colorectal adenocarcinoma (1.7%); gastrointestinal stromal tumors (1.7%); and cholangiocarcinoma (1.6%). Of all 1642 patients, 688 were female, and most (74%) were 51–80 years of age when the sample was obtained. Of patients with inactivating TSC1 and TSC2 alterations, 37.6% were in TSC1 and 62.9% were in TSC2 and included short variants (31.3% and 48.4%), rearrangements (2.7% and 6.6%), and copy number deletions (3.5% and 7.4%), respectively. TMB was low (&lt;6 mutations/megabase) in 58% of patients, and most patients had microsatellite stable (MSS; 71.3%) tumors. Other commonly mutated genes in this cohort were TP53 (62.7%), APC (38.5%) and KRAS (30.4%). Conclusions: TSC1 and/or TSC2 alterations were commonly observed in GI cancers. These cancers were frequently microsatellite stable and of low TMB suggesting that these are actionable alterations that may be candidates for targeted therapy. This hypothesis is being tested in the PRECISION 1 (NCT05103358) trial which is open for enrollment or just-in-time clinical trial sites and available to patients with GI cancers harboring TSC1 or TSC2 alterations.

Overall survival and long-term safety with ripretinib vs sunitinib in patients with advanced gastrointestinal stromal tumor previously treated with imatinib: Final analyses from INTRIGUE.

748 Background: Ripretinib is a switch-control tyrosine kinase inhibitor approved for patients (pts) with gastrointestinal stromal tumor (GIST) who received prior treatment with 3 or more kinase inhibitors, including imatinib. Sunitinib is approved for advanced GIST after imatinib failure. In the second interim analysis of overall survival (OS) from the phase 3 INTRIGUE study, the OS event rate was 41% in the all-patient (AP) intent-to-treat (ITT) population, and OS was similar between treatment arms in both the KIT exon 11 ITT and AP ITT populations. Here, we present the final OS and updated safety from INTRIGUE. Methods: INTRIGUE (NCT03673501) is an open-label, phase 3 study of adults with advanced GIST who had disease progression on or intolerance to imatinib. Randomization was 1:1 to ripretinib 150 mg once daily (QD) or sunitinib 50 mg QD (4 weeks on/2 weeks off) and was stratified by KIT mutational status and imatinib intolerance. OS was a key secondary endpoint (the primary endpoint of progression-free survival was reported previously); final OS analysis was prespecified to occur with ≥200 and ≥145 events in the AP ITT and KIT exon 11 ITT populations, respectively. Data cutoff was March 15, 2023. Results: Of 453 pts, 444 received treatment; 40 remain on treatment (ripretinib, 28/223 [13%]; sunitinib, 12/221 [5%]). Treatment discontinuation was due to progressive disease (PD) by independent radiologic review (56%), PD by investigator (11%), clinical PD (6%), withdrawal of consent (6%), and adverse events (AEs; 5%). Fewer pts discontinued treatment due to AEs with ripretinib vs sunitinib (3% vs 6%). There were 211 OS events (47%) in the AP ITT population and 151 OS events (46%) in the KIT exon 11 ITT population. OS was similar with ripretinib vs sunitinib in the 2 ITT populations (Table). Fewer pts had grade 3/4 treatment-emergent AEs with ripretinib vs sunitinib (43% vs 67%). Dose interruptions and reductions were lower with ripretinib vs sunitinib. Median treatment duration for ripretinib vs sunitinib was 7.9 vs 6.5 months. Conclusions: In the finalOS analysis from the INTRIGUE study, OS was similar between treatment arms. The safety profile remained consistent and more favorable for ripretinib vs sunitinib in pts with advanced GIST previously treated with imatinib. Clinical trial information: NCT03673501 . [Table: see text]