0000000000222028
AUTHOR
Piotr Rutkowski
Targeted Therapy in Gastrointestinal Stromal Tumors
Advances in the understanding of the molecular mechanisms of gastrointestinal stromal tumors (GISTs) pathogenesis have resulted in the development of a treatment approach which has become a model of targeted therapy in oncology. The introduction of imatinib mesylate [inhibiting KIT/PDGFRA (platelet-derived growth factor receptor-α) and their downstream signaling cascade] has dramatically improved the therapy of advanced (inoperable and/or metastatic) GIST. Imatinib has now become the standard of care in the treatment of patients with advanced GIST and its efficacy has been proven also in adjuvant setting after resection of primary high-risk tumors. However, a majority of patients eventually…
Adjuvant Imatinib in Patients with GIST Harboring Exon 9 KIT Mutations : Results from a Multi-institutional European Retrospective Study
[Purpose] The effect of high-dose imatinib (800 mg/day) on survival in the adjuvant treatment of patients with resected KIT exon 9–mutated gastrointestinal stromal tumors (GIST) is not established. Here, the association of dose and other clinicopathologic variables with survival was evaluated in a large multi-institutional European cohort.
Guidelines for time-to-event end point definitions in sarcomas and gastrointestinal stromal tumors (GIST) trials: results of the DATECAN initiative (Definition for the Assessment of Time-to-event Endpoints in CANcer trials)
ABSTRACT The DATECAN initiative (Definition for the Assessment of Time-to-event Endpoints in CANcer trials) aims to provide recommendations for definitions of time-to-event end points in cancer randomized controlled trials. We relied on a consensus method based on a multidisciplinary panel of experts to develop these guidelines for trials on sarcomas and gastrointestinal stromal tumors. Background The use of potential surrogate end points for overall survival, such as disease-free survival (DFS) or time-to-treatment failure (TTF) is increasingly common in randomized controlled trials (RCTs) in cancer. However, the definition of time-to-event (TTE) end points is rarely precise and lacks unif…
Randomized Phase 3 Trial of Regorafenib in Patients (Patients) with Metastatic and/or Unresectable Gastrointestinal Stromal Tumor (GIST) Progressing Despite Prior Treatment with at Least Imatinib (IM) and Sunitinib (SU) : Grid Trial
LBA10008 Background: Oral multikinase inhibitor regorafenib (REG) demonstrated substantial activity in a phase II trial in pts with GIST after failure of both IM and SU (J Clin Oncol. 2011; 29:606s; abstr 10007). This phase III, randomized, double-blind, placebo-controlled trial evaluated the efficacy and safety of REG for this unmet clinical need. Methods: Eligible pts had metastatic and/or unresectable GIST, objective failure of both prior IM and SU (progressive disease [PD] on, or intolerance to, IM and PD on SU), ≥1 measurable lesion, ECOG performance status 0 or 1. Pts were randomized 2:1 to receive best supportive care plus either REG 160 mg po once daily (3 wks on/1 wk off) or placeb…
Overall survival at 5 years of follow-up in a phase III trial comparing ipilimumab 10 mg/kg with 3 mg/kg in patients with advanced melanoma
BackgroundWe have previously reported significantly longer overall survival (OS) with ipilimumab 10 mg/kg versus ipilimumab 3 mg/kg in patients with advanced melanoma, with higher incidences of adverse events (AEs) at 10 mg/kg. This follow-up analysis reports a 5-year update of OS and safety.MethodsThis randomized, multicenter, double-blind, phase III trial included patients with untreated or previously treated unresectable stage III or IV melanoma. Patients were randomly assigned (1:1) to ipilimumab 10 mg/kg or 3 mg/kg every 3 weeks for 4 doses. The primary end point was OS.ResultsAt a minimum follow-up of 61 months, median OS was 15.7 months (95% CI 11.6 to 17.8) at 10 mg/kg and 11.5 mont…
Gene Signatures in Gastrointestinal Stromal Tumors
Gastrointestinal stromal tumors (GISTs) constitute a rare heterogeneous group of the most common mesenchymal neoplasm of gastrointestinal tract (GI). GISTs have emerged during the recent years as a distinct sarcoma entity due to advances in the understanding of molecular mechanism of their pathogenesis. They are believed to originate from precursors shared with interstitial cells of Cajal (ICC) – the pacemaker cells of the gut (for which CD117 antigen is the immunohistochemical marker), and they may arise along all GI (most commonly in the stomach or the small bowel) or rarely elsewhere. Their biological behavior is difficult to predict, ranging from clinically benign to malignant. The trea…
Results from a phase III trial (GRID) evaluating regorafenib (REG) in metastatic gastrointestinal stromal tumour (GIST): Subgroup analysis of outcomes based on pretreatment characteristics
10551 Background: REG, an oral receptor kinase inhibitor with activity against KIT, PDGFR, VEGFR, FGFRs, and other oncologic targets, demonstrated significant improvement in progression-free survival (PFS) over placebo (PL) in a phase III study (GRID) of patients (pts) with advanced GIST following failure of at least imatinib (IM) and sunitinib (SU). To understand the impact of pts’ baseline characteristics on outcome, we performed an exploratory analysis of REG effects across pt subgroups based on sex, age, and mitotic index of primary GIST tissue, as well as duration and number of lines of previous therapies. Methods: Adult pts with metastatic GIST (n=199) progressing after at least IM a…
Mutational analysis of plasma DNA from patients (pts) in the phase III GRID study of regorafenib (REC) versus placebo (PL) in tyrosine kinase inhibitor (TKI)-refractory GIST: Correlating genotype with clinical outcomes
10503 Background: The phase III GRID study showed that REG provides a significant improvement in progression-free survival (PFS) compared with PL in pts with advanced gastrointestinal stromal tumors (GIST) following failure of at least imatinib (IM) and sunitinib (SU; HR 0.27, p<0.0001). Determining GIST genotype in TKI-refractory disease has proven challenging due to inter-tumoral heterogeneity and pt preference to avoid serial biopsies. To overcome this, we analysed circulating DNA in plasma as a source of tumor DNA and studied the correlation between mutational status and clinical outcome. Methods: DNA was isolated from both archival tumor tissue (n=102) and plasma at baseline (n=163…
Abstract LB-295: Detection of oncogenic kinase mutations in circulating plasma DNA and correlation with clinical benefit in the phase III GRID study of regorafenib vs placebo in TKI-refractory metastatic GIST.
Abstract Background: GRID is a phase III study for patients with advanced gastrointestinal stromal tumors (GIST) following failure of imatinib (I) and sunitinib (S) who were randomized to receive either the multikinase inhibitor regorafenib (R) or placebo (P). R demonstrated a highly significant improvement in progression-free survival compared with P (HR 0.27, p&lt;0.0001). A preplanned retrospective biomarker analysis was conducted to assess GIST genotypes in GRID patients and to explore the possible impact of different driver oncogene mutations on clinical outcomes. Methods: DNA was isolated from archival tumor tissue and analyzed for KIT mutations via Sanger sequencing. The expectat…
Role of adjuvant imatinib dose in radically resected GIST harboring KIT exon 9 mutations
11533 Background: Gastrointestinal stromal tumors (GIST) with a driver mutation in KIT exon 9 (Ex9) represent about 10% of all newly diagnosed cases. In the metastatic setting, Ex9-mutated GIST patients benefit from higher doses of imatinib (800 mg/day vs standard 400 mg/day). The additional therapeutic benefit from a higher dose of imatinib in the adjuvant setting in this molecular subgroup has not been confirmed. Methods: We retrospectively identified 105 patients (pts) with resected Ex9-mutated GIST treated with adjuvant imatinib (800 mg/day or 400 mg/day) in 15 different European centers. Disease-Free Survival (DFS) and Imatinib Failure-Free Survival (IFFS) were calculated and analyzed…