Ripretinib versus sunitinib in gastrointestinal stromal tumor: ctDNA biomarker analysis of the phase 3 INTRIGUE trial

Monitoring advanced gastrointestinal stromal tumor with circulating tumor DNA

PURPOSE OF REVIEW

This review explores the role of circulating tumor (ct)DNA as a biomarker for clinical decision-making and monitoring purposes in metastatic gastrointestinal stromal tumor (GIST) patients. We discuss key insights from recent clinical trials and anticipate the future perspectives of ctDNA profiling within the clinical landscape of GIST.

RECENT FINDINGS

The identification and molecular characterization of KIT/platelet-derived growth factor receptor alpha (PDGFRA) mutations from ctDNA in metastatic GIST is feasible and reliable. Such identification through ctDNA serves as a predictor of clinical outcomes to tyrosine-kinase inhibitors (TKIs) in metastatic patients. Additionally, conjoined ctDNA analysis from clinical trials reveal the evolving mutational landscapes and increase in intratumoral heterogeneity across treatment lines. Together, this data positions ctDNA determination as a valuable tool for monitoring disease progression and guiding therapy in metastatic patients. These collective efforts culminated in the initiation of a ctDNA-based randomized clinical trial in GIST, marking a significant milestone in integrating ctDNA testing into the clinical care of GIST patients.

SUMMARY

The dynamic field of ctDNA technologies is rapidly evolving and holds significant promise for research. Several trials have successfully validated the clinical utility of ctDNA in metastatic GIST, laying the foundations for its prospective integration into the routine clinical management of GIST patients.

Role played by MDSC in colitis-associated colorectal cancer and potential therapeutic strategies

Colitis-associated colorectal cancer has been a hot topic in public health issues worldwide. Numerous studies have demonstrated the significance of myeloid-derived suppressor cells (MDSCs) in the progression of this ailment, but the specific mechanism of their role in the transformation of inflammation to cancer is unclear, and potential therapies targeting MDSC are also unclear. This paper outlines the possible involvement of MDSC to the development of colitis-associated colorectal cancer. It also explores the immune and other relevant roles played by MDSC, and collates relevant targeted therapies against MDSC. In addition, current targeted therapies for colorectal cancer are analyzed and summarized.

KIT/PDGFRA inhibitors for the treatment of gastrointestinal stromal tumors: getting to the gist of the problem

INTRODUCTION

Approximately 90% of gastrointestinal stromal tumors (GISTs) are driven by activating mutations in receptor tyrosine-kinases KIT or PDGFRA. Despite the outstanding results of first-line imatinib in advanced GIST, resistance ultimately occurs mainly through secondary mutations in KIT/PDGFRA. Other tyrosine-kinase inhibitors (TKIs) with a broader spectrum of activity against these mutations are approved after imatinib failure. However, response rates and progression-free survival are drastically lower compared to imatinib. Notably, imatinib also triggers early tolerance adaptation mechanisms, which precede the occurrence of secondary mutations.

AREAS COVERED

In this review, we outline the current landscape of KIT inhibitors, discuss the novel agents, and present additional biological pathways that may be therapeutically exploitable.

EXPERT OPINION

The development of broad-spectrum and highly selective TKIs able to induce a sustained KIT/PDGFRA inhibition is the pillar of preclinical and clinical investigation in GIST. However, it is now recognized that the situation is more intricate, with various factors interacting with KIT and PDGFRA, playing a crucial role in the response and resistance to treatments. Future strategies in the management of advanced GIST should integrate driver inhibition with the blockade of other molecules to enhance cell death and establish enduring responses in patients.

Efficacy and Safety of Ripretinib in Advanced Gastrointestinal Stromal Tumors within an Expanded Access Program: A Cohort Study

Ripretinib, a novel tyrosine kinase inhibitor used in advanced gastrointestinal stromal tumors (GIST) resistant to standard therapies, was assessed in the United Kingdom (UK) within an Expanded Access Program (EAP). A retrospective review of patients treated between January 2020 and October 2021 within the ripretinib EAP in our Institution was conducted. Clinician-documented and mRECIST 1.1 assessments were collected. The primary endpoints were progression-free survival (PFS) and time to treatment discontinuation (TTD). Treatment beyond progression (TBP), overall survival (OS), objective response rates and safety data were also analyzed. Survival curves were constructed using the Kaplan-Meier method, and univariate and multivariate Cox regression analyses were performed. All analyses were performed with R software. Overall, forty-five patients were included. After a median follow-up of 24.2 (95% CI 19.7-29.7) months, the median PFS of the group receiving 150 mg ripretinib once daily (OD) was 7.9 (95% CI 5.6-19.3) months. In the cohort of 22 patients with dose escalation upon tumor progression to 150 mg ripretinib twice daily (BD), the median PFS from BD was 5.4 (95% CI 2.8-9.3) months. Overall, median PFS and OS values for patients on ripretinib were 9.7 (95% CI 8.3-18.1) and 14.0 (95% CI 9.9-NA) months, respectively. TTD was similar to PFS. TBP was observed in about one third of all patients. Objective responses to ripretinib OD and BD treatments were observed in 16.7% and 10.0% of the patients, respectively. No new safety signals were identified. In conclusion, patients with advanced GIST receiving ripretinib in the UK within the EAP reported prolonged benefits, in line with the recent phase III clinical trials.

Exploring Perforated Jejunal GIST: A Rare Case Report and Review of Molecular and Clinical Literature

This case report details a rare instance of a perforated jejunal gastrointestinal stromal tumor (GIST) in a 76-year-old female patient. The patient presented with acute abdominal pain and distension without any changes in bowel habits or episodes of nausea and vomiting. Initial diagnostics, including abdominal plain radiography and ultrasonography, were inconclusive; however, a computed tomography (CT) scan revealed pneumoperitoneum and an irregular fluid collection suggestive of small intestine perforations. Surgical intervention uncovered a 35 mm jejunal GIST with a 10 mm perforation. Histopathological examination confirmed a mixed cell type GIST with high malignancy potential, further substantiated by immunohistochemistry markers CD117, DOG1, and vimentin. Molecular analysis illuminated the role of key oncogenes, primarily KIT and PDGFRA mutations, emphasizing the importance of molecular diagnostics in GIST management. Despite the severity of the presentation, the patient's postoperative recovery was favorable, highlighting the effectiveness of prompt surgical and multidisciplinary approaches in managing complex GIST cases.