Phase III study of nilotinib versus best supportive care with or without a TKI in patients with gastrointestinal stromal tumors resistant to or intolerant of imatinib and sunitinib

Twenty-one-year report from the Danish Health Authority Expert Advisory Panel for review of treatment of 10 000 cancer patients

BACKGROUND

Patients with hard-to-treat or rare cancers and those not responding to standard-of-care (SoC) treatment have unmet needs. Limited access to novel drugs is an increasing additional challenge. In 2003, the Danish government adopted a Health Act to ensure that treatment of patients with life-threatening disease could be reevaluated by independent experts. The Danish Health Authority (DHA) set up an Expert Advisory Panel to provide advice on possibilities for further treatment of patients, including treatment not approved nationally. A few years later, clinical units were established that could offer unestablished treatment to patients by referral from the Panel. The treatment was first reimbursed by the Government and later by regional authorities.

MATERIALS AND METHODS

We present the structure, workflow, and impact of the Health Act for 21 years for patients with cancer. Annual reports from the DHA were the primary data source.

RESULTS

11 034 cases from 9603 cancer patients were evaluated by the Panel from 2003 to 2023, representing a median of 372 unique cases yearly. In 53%, the Panel advised on further treatment in Denmark, and of these, 56% were recommended nationally nonapproved treatment, 21% SoC treatment or workup, and 19% clinical trial participation. In 4.5% of cases, advice was given on treatment abroad. A significant decline in admissions to the Panel from a peak of 1167 patients in 2008 to 3-400 yearly from 2012 to 2017 followed the conversion of nonapproved treatments to SoC practice. A shift in drug reimbursement, independent of Panel advise, reduced the clinical impact and explained the further decline observed in admissions lately to only 51 patients in 2023.

CONCLUSIONS

This unique national scheme provided early access to treatment for patients with no further SoC options and facilitated the introduction of new cancer treatments, initiation of clinical trials, and establishment of trial units in the country. The scheme may be adapted to other countries with a public healthcare system. Results of the current report indicate that impact is dependent on delivering clinical units and reimbursement associated with the recommended treatment.

Chemotherapeutic potential of radotinib against blood and solid tumors: A beacon of hope in drug repurposing

Tyrosine kinase inhibitors (TKIs) represent a pivotal class of targeted therapies in oncology, with multiple generations developed to address diverse molecular targets. Imatinib is the first TKI developed to target the BCR-ABL1 chimeric protein, which is the key driver oncogene implicated in Philadelphia chromosome-positive chronic myeloid leukemia (CML). Several second-generation tyrosine kinase inhibitors (2GTKIs), such as nilotinib, dasatinib, bosutinib, and radotinib (RTB), followed the groundbreaking introduction of imatinib. RTB occupies the unique position of being the least explored member of this class. While nilotinib, dasatinib, and bosutinib have garnered significant attention and extensive research focus, RTB remains relatively uncharted in comparison to its counterparts. Fundamental drug characteristics, such as the pharmacokinetic and pharmacodynamic properties of RTB, remain unavailable in existing sources. Compared to other 2GTKIs, RTB has been less utilized in combinatorial drug studies, and no investigations have been reported on its effects on solid tumors to date. However, the effects of RTB have been studied in acute myeloid leukemia (AML), multiple myeloma (MM), Parkinson's disease, and idiopathic pulmonary fibrosis (IPF). Although RTB has been investigated in some conditions, these studies are still in their preliminary stages and are comparatively lesser than studies on other 2GTKIs. This review is the first attempt that extensively presents a compilation of data on RTB and describes its therapeutic potential against blood and solid tumors. Further investigations on RTB could expand its chemotherapeutic usage in various solid tumors and enhance the possibility of drug repurposing in cancer therapy.

Nilotinib boosts the efficacy of anti-PDL1 therapy in colorectal cancer by restoring the expression of MHC-I

BACKGROUND

Although immune checkpoint inhibitors (ICIs) have revolutionized the landscape of cancer treatment, only a minority of colorectal cancer (CRC) patients respond to them. Enhancing tumor immunogenicity by increasing major histocompatibility complex I (MHC-I) surface expression is a promising strategy to boost the antitumor efficacy of ICIs.

METHODS

Dual luciferase reporter assays were performed to find drug candidates that can increase MHC-I expression. The effect of nilotinib on MHC-I expression was verified by dual luciferase reporter assays, qRT-PCR, flow cytometry and western blotting. The biological functions of nilotinib were evaluated through a series of in vitro and in vivo experiments. Using RNA-seq analysis, immunofluorescence assays, western blotting, flow cytometry, rescue experiments and microarray chip assays, the underlying molecular mechanisms were investigated.

RESULTS

Nilotinib induces MHC-I expression in CRC cells, enhances CD8+ T-cell cytotoxicity and subsequently enhances the antitumor effects of anti-PDL1 in both microsatellite instability and microsatellite stable models. Mechanistically, nilotinib promotes MHC-I mRNA expression via the cGAS-STING-NF-κB pathway and reduces MHC-I degradation by suppressing PCSK9 expression in CRC cells. PCSK9 may serve as a potential therapeutic target for CRC, with nilotinib potentially targeting PCSK9 to exert anti-CRC effects.

CONCLUSION

This study reveals a previously unknown role of nilotinib in antitumor immunity by inducing MHC-I expression in CRC cells. Our findings suggest that combining nilotinib with anti-PDL1 therapy may be an effective strategy for the treatment of CRC.

Evaluation of Systemic Treatment Options for Gastrointestinal Stromal Tumours

Gastrointestinal stromal tumours (GIST) are the most common mesenchymal tumours of the gastrointestinal tract. Surgical treatment is recommended for the majority of localised GIST, while systemic treatment is the cornerstone of management for metastatic or unresectable disease. While a three-year regimen of imatinib is the standard of care in the adjuvant setting, there is no precise recommendation for the duration of neoadjuvant treatment, where imatinib is usually given between 4 and 12 months. Continuous treatment with imatinib at a dose of 400 mg once per day is recommended for most patients with unresectable or metastatic GIST in the first line. An exception is represented by patients with tumours harbouring the imatinib-insensitive PDGFRA D842V mutation who would be better treated with avapritinib. Targeted therapies are also recommended in the presence of NTRK rearrangements and BRAF mutations, although limited data are available. While an increase in the dose of imatinib to 800 mg is an option for the second line, sunitinib is usually considered the standard of care. Similar outcomes were reported for ripretinib in patients with tumours harbouring KIT exon 11 mutation, with significantly fewer side effects. Regorafenib and ripretinib are the standards of care in the third and fourth lines, respectively. The recent development of various systemic treatment options allows for a more personalised approach based on the molecular profile of the GIST, patient characteristics, and the profile of medications' adverse events. A multidisciplinary approach is paramount since combining systemic treatment with locoregional treatment options and supportive care is vital for long-term survival.

Emerging Targeted Therapeutic Strategies to Overcome Imatinib Resistance of Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumors (GISTs) are the most common malignant mesenchymal neoplasms of the gastrointestinal tract. The gold standard for the diagnosis of GISTs is morphologic analysis with an immunohistochemical evaluation plus genomic profiling to assess the mutational status of lesions. The majority of GISTs are driven by gain-of-function mutations in the proto-oncogene c-KIT encoding the tyrosine kinase receptor (TKR) known as KIT and in the platelet-derived growth factor-alpha receptor (PDGFRA) genes. Approved therapeutics are orally available as tyrosine kinase inhibitors (TKIs) targeting KIT and/or PDGFRA oncogenic activation. Among these, imatinib has changed the management of patients with unresectable or metastatic GISTs, improving their survival time and delaying disease progression. Nevertheless, the majority of patients with GISTs experience disease progression after 2-3 years of imatinib therapy due to the development of secondary KIT mutations. Today, based on the identification of new driving oncogenic mutations, targeted therapy and precision medicine are regarded as the new frontiers for GISTs. This article reviews the most important mutations in GISTs and highlights their importance in the current understanding and treatment options of GISTs, with an emphasis on the most recent clinical trials.

Molecular Mechanisms of Gastrointestinal Stromal Tumors and Their Impact on Systemic Therapy Decision

Gastrointestinal stromal tumors (GISTs) are soft tissue sarcomas that mostly derive from Cajal cell precursors. They are by far the most common soft tissue sarcomas. Clinically, they present as gastrointestinal malignancies, most often with bleeding, pain, or intestinal obstruction. They are identified using characteristic immunohistochemical staining for CD117 and DOG1. Improved understanding of the molecular biology of these tumors and identification of oncogenic drivers have altered the systemic treatment of primarily disseminated disease, which is becoming increasingly complex. Gain-of-function mutations in KIT or PDGFRA genes represent the driving mutations in more than 90% of all GISTs. These patients exhibit good responses to targeted therapy with tyrosine kinase inhibitors (TKIs). Gastrointestinal stromal tumors lacking the KIT/PDGFRA mutations, however, represent distinct clinico-pathological entities with diverse molecular mechanisms of oncogenesis. In these patients, therapy with TKIs is hardly ever as effective as for KIT/PDGFRA-mutated GISTs. This review provides an outline of current diagnostics aimed at identifying clinically relevant driver alterations and a comprehensive summary of current treatments with targeted therapies for patients with GISTs in both adjuvant and metastatic settings. The role of molecular testing and the selection of the optimal targeted therapy according to the identified oncogenic driver are reviewed and some future directions are proposed.

Progress in the Treatment of Small Intestine Cancer

OPINION STATEMENT

Small intestine cancer is rare, accounting for approximately 3% of all gastrointestinal malignancies. The most common histological subtypes include adenocarcinoma, neuroendocrine tumours (NETs) and gastrointestinal stromal tumours (GISTs). In localised disease, surgery remains the mainstay of treatment and the best approach to improve survival. Current treatment for small intestine adenocarcinoma (SIA) is extrapolated from small studies and data from colorectal cancer (CRC). There is limited evidence to guide therapy in the adjuvant setting. However, there are small phase II studies in the advanced setting providing evidence for the role of chemotherapy and immunotherapy. There is also limited evidence assessing the efficacy of targeted therapies. Small intestine NETs are rare, with evidence for somatostatin analogue therapy, particularly in the low to intermediate-grade well-differentiated tumours. Poorly differentiated NETs are generally managed with chemotherapy but have worse outcomes compared with well-differentiated NETs. The management of small intestine GISTs is largely targeting KIT mutations with imatinib. Recent trials have provided evidence for effective therapies in imatinib-resistant tumours and the potential role of immunotherapy. The aim of this article was to review the evidence for the current management and recent advances in the management of small intestine adenocarcinoma, NETs and GISTs.

A systematic review and network meta-analysis of the efficacy and safety of third-line and over third-line therapy after imatinib and TKI resistance in advanced gastrointestinal stromal tumor

Tyrosine kinase inhibitors (TKIs) have greatly improved the prognosis of unresectable and metastatic gastrointestinal stromal tumors (GISTs) in the last two decades. Imatinib and sunitinib are recommended as first-line and second-line therapies, respectively. However, there is a lack of precision therapy for refractory GISTs regarding therapy after imatinib and sunitinib. We comprehensively searched electronic databases, including PubMed, EMBASE, Web of Science, Cochrane Library, and ClinicalTrials, from inception to October 2022. Randomized controlled trials featuring comparisons with third-line or over third-line therapies against GISTs were eligible. The primary outcome was progression-free survival (PFS). All network calculations were performed using random effect models, and the ranking of regimens were numerically based on the surface under the cumulative ranking (SUCRA) statistics. A total of seven studies were eligible for inclusion in this network meta-analysis. After analysis, ripretinib was ranked at the top in progression-free survival (PFS), overall survival (OS), and disease control rate (DCR) (SUCRA statistics: 83.1%, 82.5%, and 86.5%, respectively), whereas nilotinib and pimitespib presented better tolerability (SUCRA statistics: 64.9% and 63.8%, respectively). We found that regorafenib seemed more reliable for clinical administration, and ripretinib showed good effectiveness for the over third-line therapy. Precise targeted therapy is a critical direction for the future treatment of GIST, and more high-quality studies of new agents are expected.

NCCN Guidelines® Insights: Gastrointestinal Stromal Tumors, Version 2.2022

Gastrointestinal stromal tumors (GIST) are the most common type of soft tissue sarcoma that occur throughout the gastrointestinal tract. Most of these tumors are caused by oncogenic activating mutations in the KIT or PDGFRA genes. The NCCN Guidelines for GIST provide recommendations for the diagnosis, evaluation, treatment, and follow-up of patients with these tumors. These NCCN Guidelines Insights summarize the panel discussion behind recent important updates to the guidelines, including revised systemic therapy options for unresectable, progressive, or metastatic GIST based on mutational status, and updated recommendations for the management of GIST that develop resistance to specific tyrosine kinase inhibitors.

Current Molecular Profile of Gastrointestinal Stromal Tumors and Systemic Therapeutic Implications

Gastrointestinal stromal tumors (GISTs) are malignant mesenchymal tumors arising from the intestinal pacemaker cells of Cajal. They compose a heterogenous group of tumors due to a variety of molecular alterations. The most common gain-of-function mutations in GISTs are either in the KIT (60-70%) or platelet-derived growth factor receptor alpha (PDGFRA) genes (10-15%), which are mutually exclusive. However, a smaller subset, lacking KIT and PDGFRA mutations, is considered wild-type GISTs and presents distinct molecular findings with the activation of different proliferative pathways, structural chromosomal and epigenetic changes, such as inactivation of the NF1 gene, mutations in the succinate dehydrogenase (SDH), BRAF, and RAS genes, and also NTRK fusions. Currently, a molecular evaluation of GISTs is imperative in many scenarios, aiding in treatment decisions from the (neo)adjuvant to the metastatic setting. Here, we review the most recent data on the molecular profile of GISTs and highlight therapeutic implications according to distinct GIST molecular subtypes.

An overview of agents and treatments for PDGFRA-mutated gastrointestinal stromal tumors

Platelet-derived growth factor receptor A (PDGFRA) mutations occur in approximately 10-15% of gastrointestinal stromal tumors (GISTs). These tumors with PDGFRA mutations have a different pathogenesis, clinical characteristics, and treatment response compared to tumors with receptor tyrosine kinase protein (KIT) mutations (60-70%). Many clinical studies have investigated the use of tyrosine kinase inhibitors mainly in patients with KIT mutations; however, there is a lack of attention to the PDGFRA-mutated molecular subtype. The main effective inhibitors of PDGFRA are ripretinib, avapritinib, and crenolanib, and their mechanisms and efficacy in GIST (as confirmed in clinical trials) are described in this review. Some multi-targeted tyrosine kinase inhibitors with inhibitory effects on this molecular subtype are also introduced and summarized in this paper. This review focuses on PDGFRA-mutated GISTs, introduces their clinical characteristics, downstream molecular signaling pathways, and existing resistance mechanisms. We focus on the most recent literature that describes the development of PDGFRA inhibitors and their use in clinical trials, as well as the potential benefits from different combination therapy strategies.

Systemic Therapy for Gastrointestinal Stromal Tumor: Current Standards and Emerging Challenges

Gastrointestinal stromal tumor (GIST), though rare, is the most common mesenchymal tumors of the gastrointestinal tract. KIT or PDGFRα mutation plays as an oncogenic driver in the majority of GISTs. Surgical resection is the only curative treatment for localized disease. The discovery of imatinib with promising anti-tumor effect and successive tyrosine kinase inhibitors (TKI), including second-line sunitinib and third-line regorafenib, revolutionized the management of advanced and metastatic GIST over the past two decades. Recently, ripretinib and avapritinib were approved for the fourth line setting and for PDGFRA exon 18-mutant GIST in first-line setting, respectively. Despite multi-line TKIs exerted ability of disease control, drug resistance remained an obstacle for preventing rapid disease progression. Experimental TKIs or novel therapeutic targets may further improve treatment efficacy. Immune checkpoint inhibitors such as anti-programmed cell death protein-1 (PD1) and anti-CTL-associated antigen 4 (CTLA-4) showed moderate response in early phase trials composed of heavily pretreated patients. KIT/PDGFRα wild-type GISTs are generally less sensitive to imatinib and late-line TKIs. Recent studies demonstrated that targeting fibroblast growth factor receptor signaling may be a potential target for the wild-type GISTs.

Hematologic toxicities of sunitinib in patients with gastrointestinal stromal tumors: a systematic review and meta-analysis

PURPOSE

Sunitinib offers a significant survival benefit to patients with imatinib-resistant gastrointestinal stromal tumors (GIST). However, the incidence and risk of sunitinib-induced hematologic toxicities in such a population are often overlooked and have not been well characterized. This meta-analysis was performed to assess the summary incidence and risk of hematologic toxicities secondary to sunitinib in patients with GIST.

METHODS

Searches were performed in PubMed, Embase, Cochrane Library, and Web of Science as well as ClinicalTrials.gov to identify relevant studies up to April 2022. Studies with adequate safety profile, including anemia, neutropenia, and thrombocytopenia, were included to calculate the pooled incidence, relative risk (RR), and corresponding 95% confidence intervals (CIs). This study was registered with PROSPERO under number CRD42022328202.

RESULTS

A total of 2593 patients from 13 studies were included in the present meta-analysis. For patients with GIST assigned to sunitinib, the overall incidences of all-grade anemia, neutropenia, and thrombocytopenia were 26.2% (95% CI, 14.9-39.4%), 41.8% (95% CI, 29.0-55.1%), and 36.4% (95% CI, 22.8-51.1%), respectively. Regarding high-grade (grades 3 and 4) events, there were 4.7% (95% CI, 3.8-5.6%) for anemia, 9.3% (95% CI, 5.6-13.7%) for neutropenia and 5.0% (95% CI, 2.9-7.3%) for thrombocytopenia. Compared to placebo arms, sunitinib was related to an increased risk of high-grade neutropenia with an RR of 10.39 (95% CI, 1.53-70.72; p = 0.017).

CONCLUSIONS

Sunitinib carries a relatively high incidence of hematologic toxicities and a substantial increased risk of high-grade neutropenia in patients with GIST. Appropriate prevention and management seem to be inevitable.

Treatment of Gastrointestinal Stromal Tumors (GISTs): A Focus on Younger Patients

Gastrointestinal stromal tumors (GISTs) originate from Cajal's cells and are the most common mesenchymal neoplasms of the gastrointestinal tract. GISTs in young adults, i.e., patients before the age of 40, are rare and differ from those in older patients and GISTs in children in terms of the molecular and clinical features, including the location and type of mutations. They often harbor other molecular abnormalities than KIT and PDGFRA mutations (wild-type GISTs). The general principles of therapeutic management in young patients are the same as in the elderly. Considering some differences in molecular abnormalities, molecular testing should be the standard procedure to allow appropriate systemic therapy if needed. The optimal treatment strategy should be established by a multidisciplinary team experienced in sarcoma treatment. The impact of treatment on the quality of life and daily activities, including the impact on work, pregnancy, and fertility, in this patient population should be especially taken into consideration.

The GIST of Advances in Treatment of Advanced Gastrointestinal Stromal Tumor

Gastrointestinal stromal tumor (GIST) is the most common malignant neoplasm of mesenchymal origin and a compelling clinical and biologic model for the rational development of molecularly targeted agents. This is because the majority of GISTs are driven by gain-of-function mutations in KIT or PDGFRA receptor tyrosine kinases. Specific GIST mutations circumscribe well-defined molecular subgroups that must be determined during the diagnostic work-up to guide clinical management, including therapeutic decisions. Surgery is the cornerstone treatment in localized disease and can also be clinically relevant in the metastatic setting. The correct combination and sequence of targeted agents and surgical procedures improves outcomes for patients with GIST and should be discussed individually within multidisciplinary expert teams. All currently approved agents for the treatment of GIST are based on orally available tyrosine kinase inhibitors targeting KIT and PDGFRA oncogenic activation. Although first-line imatinib achieves remarkable prolonged disease control, the benefit of subsequent lines of treatment is more modest. Novel therapeutic strategies focus on overcoming the heterogeneity of KIT or PDGFRA secondary mutations and providing more potent inhibition of specific challenging mutations. This article reviews the current understanding and treatment of GIST, with an emphasis on recent advances.

Health-Related Quality of Life and Side Effects in Gastrointestinal Stromal Tumor (GIST) Patients Treated with Tyrosine Kinase Inhibitors: A Systematic Review of the Literature

BACKGROUND

The introduction of tyrosine kinase inhibitors (TKIs) has revolutionized the treatment of gastrointestinal stromal tumors (GISTs), resulting in a substantial gain in median overall survival. Subsequently, health-related quality of life (HRQoL) has become more relevant. Here, we systematically review the available literature on HRQoL issues and side effects of different TKIs registered for the treatment of GIST.

METHODS

A search through five databases was performed. Full reports in English describing HRQoL outcomes and/or side effects in GIST patients on TKI therapy were included.

RESULTS

A total of 104 papers were included; 13 studies addressed HRQoL, and 96 studies investigated adverse events. HRQoL in patients treated with imatinib, regorafenib, and ripretinib remained stable, whereas most sunitinib-treated patients reported a decrease in HRQoL. Severe fatigue and fear of recurrence or progression were specifically assessed as HRQoL issues and had a negative impact on overall HRQoL as well as psychological and physical well-being. The majority of studies focused on physician-reported side effects. Nearly all GIST patients treated with a TKI experienced at least one adverse event, mostly mild to moderate.

CONCLUSIONS

Despite the fact that almost all patients treated with a TKI experienced side effects, this did not seem to affect overall HRQoL during TKI therapy. In daily practice, it are the side effects that hamper a patient's HRQoL resulting in treatment adjustments, suggesting that the reported side effects were underestimated by physicians, or the measures used to assess HRQoL do not capture all relevant issues that determine a GIST patient's HRQoL.

Medical Oncological Treatment for Patients with Gastrointestinal Stromal Tumour (GIST) - a Systematic Review

BACKGROUND

Chemotherapy is ineffective in treating patients with Gastrointestinal Stromal Tumour (GIST). However, several types of tyrosine kinase inhibitors have been investigated since the approval of imatinib in 2001. The purpose of this report was to systematically review studies on the efficacy of neoadjuvant, adjuvant, and lifelong medical oncological treatment of GIST.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed throughout the review process. The protocol was submitted to the International prospective register of systematic reviews database (ID 251724). A systematic literature search was performed, including phase II- and III studies of biological treatment, reporting on treatment effect in patients with GIST.

RESULTS

Of 308 identified publications, 42 studies were included in this review.

CONCLUSION

This review gives an overview of the existing evidence for approved lines of oncological treatments and potential alternatives for patients with GIST in the neoadjuvant-, adjuvant- and life-long setting.

Surgical resection for patients with recurrent or metastatic gastrointestinal stromal tumors: a protocol for a systematic review and meta-analysis update

BACKGROUND

There are limited data on the clinical benefits of adding surgical resection in patients with recurrent or metastatic gastrointestinal stromal tumors (GISTs). This protocol outlines the planned scope and methods for a systematic review and meta-analysis update that will compare the clinical outcomes of surgical resection combined with tyrosine kinase inhibitor (TKI) with TKI treatment alone in patients with recurrent or metastatic GISTs.

METHODS

This review will update a previously published systematic review by our team. This protocol is presented in accordance with the PRISMA-P guideline. PubMed, Embase, and Cochrane Central Register of Controlled Trials will be systematically searched and supplemented by a secondary screening of the references of all included studies. We will include randomized controlled trials (RCTs) and non-randomized studies (NRS) in this review update. The outcomes evaluated will be overall survival and progression-free survival. Two reviewers will independently screen and select studies, extract data from the included studies, and assess the risk of bias of the included studies. Data extracted from RCTs and NRS will be analysed and reported separately. Preplanned subgroup analyses and sensitivity analyses are detailed within this protocol. The strength of the body of evidence will be assessed using GRADE.

DISCUSSION

This systematic review and meta-analysis update will provide a current assessment of the evidence for the role of surgery in patients with recurrent or metastatic advanced GISTs. These findings will be used by the Chinese Society of Clinical Oncology (CSCO) GIST guideline recommendations on surgical treatment for recurrent or metastatic advanced GIST patients in China.

SYSTEMATIC REVIEW REGISTRATION

This protocol was prospectively registered in the Open Science Framework Registry ( https://osf.io/xus7m ).

Treatment of gastrointestinal stromal tumors: A single-center experience

OBJECTIVE:

Gastrointestinal stromal tumors are the most common mesenchymal tumors of the gastrointestinal tract. We aimed to examine the clinical characteristics and treatment outcomes of patients diagnosed with gastrointestinal stromal tumor (GIST) who were followed up and treated in our center.

METHODS:

This study retrospectively evaluated the clinical characteristics, disease stages, administered treatments, and treatment responses of 67 patients diagnosed with GIST who presented to our center between 2007 and 2015.

RESULTS:

Of the 67 patients included in our study, 24 (35.8%) were female and 43 (64.2%) were male. Median age at diagnosis was 54 years (23–86). Primary tumor localization was the stomach in 38.8% (n=26), small intestine in 46.2% (n=31), colorectal in 6% (n=4), and extra-gastrointestinal in 9% (n=6) of the patients. At diagnosis, 19 patients (28.4%) were at a metastatic stage. Fifty-seven patients (85.1%) underwent surgery. Thirty-three patients received one line, 20 patients received two lines, and 12 patients received three lines of treatment. The first-line treatment resulted in complete response in 12 patients (36.4%), partial response in 15 patients (45.5%), stable disease in 5 patients (15.2%), and progression in 1 patient (3%). Progression-free survival (PFS) was 36 months for the first-line treatment. The second-line treatment resulted in partial response in 7 patients (35%), stable disease in 12 patients (60%), and progression in 1 patient (5%). PFS was 12 months for the second-line treatment. The third-line treatment resulted in complete response in 1 patient (8.3%), partial response in 3 patients (25%), stable disease in 5 patients (41.7%), and progression in 3 patients (25%). PFS was 9 months for the third-line treatment. The fourth-line treatment resulted in stable disease in 4 patients (80%) and progression in 1 patient (20%). PFS was 4 months for the fourth-line treatment. Overall survival was 90 months for all patients.

CONCLUSION:

The use of tyrosine kinase inhibitors such as imatinib has a significant favorable effect on the prognosis in the treatment of GISTs, both in adjuvant therapy and in advanced stage disease.

Efficacy evaluation of nilotinib treatment in different genomic subtypes of gastrointestinal stromal tumors: A meta-analysis and systematic review

Nilotinib has been used as a third-line drug for gastrointestinal stromal tumors (GISTs) after a failure of sunitinib. In this study, we aimed to evaluate the efficacy of nilotinib in different genomic subtypes of GISTs. We searched the English articles through EMBASE, Cochrane Library and PubMed Database regarding to the use of nilotinib on GISTs, which published up to February 15, 2019. Inclusion criteria were: GISTs patients received nilotinib in a clinical trial and had detailed genetic subtype records (such as KIT exon 9, KIT exon 11, or PDGFRA mutations, or wild-type). The clinical benefit rate was used to assess the efficacy of nilotinib. A total of 3 studies involving 218 GISTs were included in this meta-analysis. The overall OR (KIT group vs WT group) was 3.26 (95% CI: 1.14-9.28; P = 0.027, Pheterogeneity = 0.613). The overall OR in KIT exon 11 group vs WT group was 5.30 (95% CI: 1.79-15.68; P = 0.003, Pheterogeneity = 0.409). The overall OR in KIT exon 9 group vs WT group was 0.13 (95% CI: 0.02-0.86; P = 0.035, Pheterogeneity = 0.229). The overall OR in KIT exon 11 group vs exon 9 group was 9.96 (95% CI: 0.39-254.66; P < 0.0001, Pheterogeneity = 0.024). Different genotypes of GISTs showed different responses to nilotinib, and KIT exon 11-mutant GISTs mostly benefited from nilotinib, followed by KIT exon 9-mutant or WT one.

Treatment of Metastatic Gastrointestinal Stromal Tumors (GIST): A Focus on Older Patients

Gastrointestinal stromal tumors (GIST) originating in the Cajal cells are the most common mesenchymal neoplasms of the gastrointestinal tract. The median age of patients with this diagnosis is 65 years, and over 20% of cases affect people over the age of 70 years. The effectiveness and tolerability of systemic treatment with tyrosine kinase inhibitors in older patients with GIST seem to be similar to that in younger patients, but some studies have shown that treatment of older patients is suboptimal. Disability, frailty, comorbidities, and concomitant medications may influence treatment decisions, and toxicities also more often lead to treatment discontinuation. The known safety profile and oral administration route of the tyrosine kinase inhibitors used in GIST may allow maximization of treatment and the best efficacy, especially in older patients. This review summarizes the efficacy data for the systemic treatment of GIST, including data for older patients and from real-world experiences, if available and significant. The reported safety data and general rules for toxicity management, including appropriate patient selection and the need for careful monitoring during treatment, are also discussed.

Gastrointestinal stromal tumor: a review of current and emerging therapies

Gastrointestinal stromal tumors (GIST) are rare neoplasms arising from the interstitial cell of Cajal in the gastrointestinal tract. Two thirds of GIST in adult patients have c-Kit mutation and smaller fractions have platelet derived growth factor receptor alpha (PDGFRA) mutation. Surgery is the only curative treatment for localized disease. Imatinib improves survival when used adjuvantly and in advanced disease. Several targeted therapies have also improved survival in GIST patients after progression on imatinib including sunitinib and regorafenib. Recently, United States Federal and Drug Administration (FDA) approved two new tyrosine kinase inhibitors for the treatment of heavily pretreated advanced/unresectable GIST including avapritinib (a selective inhibitor for PDGFRA exon 18 mutation including D842V mutations) and ripretinib (a broad-spectrum kinase inhibitor of c-Kit and PDGFRA). In this article, we will provide a comprehensive review of GIST including the current standard of care treatment and exploring future paradigm shifts in therapy.

Gastrointestinal stromal tumours

Gastrointestinal stromal tumours (GIST) have an incidence of ~1.2 per 10⁵ individuals per year in most countries. Around 80% of GIST have varying molecular changes, predominantly mutually exclusive activating KIT or PDGFRA mutations, but other, rare subtypes also exist. Localized GIST are curable, and surgery is their standard treatment. Risk factors for relapse are tumour size, mitotic index, non-gastric site and tumour rupture. Patients with GIST with KIT or PDGFRA mutations sensitive to the tyrosine kinase inhibitor (TKI) imatinib that are at high risk of relapse have improved survival with adjuvant imatinib treatment. In advanced disease, median overall survival has improved from 18 months to >70 months since the introduction of TKIs. The role of surgery in the advanced setting remains unclear. Resistance to TKIs arise mainly from subclonal selection of cells with resistance mutations in KIT or PDGFRA when they are the primary drivers. Advanced resistant GIST respond to second-line sunitinib and third-line regorafenib, as well as to the new broad-spectrum TKI ripretinib. Rare molecular forms of GIST with alterations involving NF1, SDH genes, BRAF or NTRK genes generally show primary resistance to standard TKIs, but some respond to specific inhibitors of the activated genes. Despite major advances, many questions in both advanced and localized disease remain unanswered.

Comparative Efficacy and Safety of Different Regimens of Advanced Gastrointestinal Stromal Tumors After Failure Prior Tyrosine Kinase Inhibitors: A Network Meta-Analysis

INTRODUCTION

The prospect of targeted therapies for advanced gastrointestinal stromal tumors (GISTs) has been dramatically transformed after encouraging results achieved in recent clinical trials. At present, the number of second- and third-line treatments are increasing, although the challenge is to take into account the differences between these interventions. Therefore, our goal is to evaluate the investigation of different regimens currently used in GISTs based on findings from phase II or phase III randomized controlled trials (RCTs), and then indirectly compare the effectiveness and safety of the available therapies.

METHODS

The qualified literatures in relevant sources were searched systematically. Studies to identify RCTs of which main endpoints were progression-free survival (PFS), overall survival (OS), and grade 3 or more adverse events (AEs) in patients with GISTs were considered for inclusion.

RESULTS

Eight RCTs met our inclusion criteria, which involved 2351 patients. For PFS, compared with placebo, imatinib, and sunitinib, regorafenib (HR = 0.12, 95% CI 0.07-0.23; HR = 0.27, 95% CI 0.19-0.39; HR = 0.36, 95% CI 0.19-0.72, respectively) and ripretinib (HR = 0.15, 95% CI 0.09-0.25; HR = 0.33, 95% CI 0.16-0.68; HR = 0.44, 95% CI 0.25-0.78, respectively) were significantly correlated with the improvement of PFS, and regorafenib may be the preferred option according to the analysis of treatment rankings. For OS, compared with placebo, imatinib, and sunitinib, masitinib (HR = 0.13, 95% CI 0.04-0.44; HR = 0.13, 95% CI 0.04-0.51; HR = 0.27, 95%CI 0.09-0.84) and ripretinib (HR = 0.36, 95% CI 0.21-0.62; HR = 0.36, 95% CI 0.16-0.80; HR = 0.18, 95% CI 0.09-0.36, respectively) were significantly more effective, and masitinib may be the best choice according to treatment ranking analysis. Statistically, regorafenib can be considered to be the highest in high-grade AEs, while the rate of severe AEs of ripretinib and masitinib was likely the lowest.

CONCLUSION

Our results show that ripretinib has the most favorable balance between effectiveness and tolerability among the different treatment regimens for GISTs.

Systemic therapy of advanced/metastatic gastrointestinal stromal tumors: an update on progress beyond imatinib, sunitinib, and regorafenib

Introduction: Discovery of oncogenic mutations in the KIT and PDGFRA tyrosine kinase receptor was a crucial step for the development of tyrosine kinase inhibitors (TKIs). Since then, GIST became a model for the development of molecular-targeted therapy, which led to dramatically improved median overall survival of advanced GIST. Still, further progress is needed after third-line or for TKI resistant mutations. Areas covered: In this review, after a brief introduction on imatinib, sunitinib, and regorafenib, an overview of TKIs that was evaluated beyond these drugs is provided, with a main focus on the novel approved TKIs. Expert opinion: Combination therapies have thus far not fulfilled their promise in GIST, nor did immunotherapy. Increased understanding of GIST and advances in the development of molecular-targeted drugs led to the introduction of ripretinib and avapritinib. Furthermore, NTRK inhibitors became available for ultrarare NTRK fusions. Solutions for NF1 and BRAF mutated and SDH-deficient GIST are still to be awaited. This all underlines the need for adequate molecular profiling of high-risk GISTs before treatment is started. Possibly by using circulating tumor DNA in the future, targeting resistance mutations with specific drugs along the course of the disease would be easier, avoiding multiple tumor biopsies.

Financial Implications of Avapritinib for Treatment of Unresectable Gastrointestinal Stromal Tumors in Patients With a PDGFRA Exon 18 Variant or After 3 Previous Therapies in a Hypothetical US Health Plan

IMPORTANCE

With the approval of avapritinib for adults with unresectable or metastatic gastrointestinal stromal tumors (GISTs) harboring a platelet-derived growth factor receptor alpha (PDGFRA) exon 18 variant, including PDGFRA D842V variants, and National Comprehensive Cancer Network guideline recommendations as an option for patients with GIST after third-line treatment, it is important to estimate the potential financial implications of avapritinib on a payer's budget.

OBJECTIVE

To estimate the budget impact associated with the introduction of avapritinib to a formulary for metastatic or unresectable GISTs in patients with a PDGFRA exon 18 variant or after 3 or more previous treatments from the perspective of a US health plan.

DESIGN, SETTING, AND PARTICIPANTS

For this economic evaluation, a 3-year budget impact model was developed in March 2020, incorporating costs for drug acquisition, testing, monitoring, adverse events, and postprogression treatment. The model assumed that avapritinib introduction would be associated with increased PDGFRA testing rates from the current 49% to 69%. The health plan population was assumed to be mixed 69% commercial, 22% Medicare, and 9% Medicaid. Base case assumptions included a GIST incidence rate of 9.6 diagnoses per million people, a metastatic PDGFRA exon 18 mutation rate of 1.9%, and progression rate from first-line to fourth-line treatment of 17%.

EXPOSURES

The model compared scenarios with and without avapritinib in a formulary.

MAIN OUTCOMES AND MEASURES

Annual, total, and per member per month (PMPM) budget impact.

RESULTS

In a hypothetical 1-million member plan, fewer than 0.1 new patients with a PDGFRA exon 18 variant per year and 1.2 patients receiving fourth-line therapy per year were eligible for treatment. With avapritinib available, the total increase in costs in year 3 for all eligible adult patients with a PDGFRA exon 18 variant was $46 875, or $0.004 PMPM. For patients undergoing fourth-line treatment, the total increase in costs in year 3 was $69 182, or $0.006 PMPM. The combined total budget impact in year 3 was $115 604, or $0.010 PMPM, including an offset of $3607 in postprogression costs avoided or delayed. The higher rates of molecular testing resulted in a minimal incremental testing cost of $453 in year 3.

CONCLUSIONS AND RELEVANCE

These results suggest that adoption of avapritinib as a treatment option would have a minimal budget impact to a hypothetical US health plan. This would be primarily attributable to the small eligible patient population and cost offsets from reduced or delayed postprogression costs.

Utility of Circulating Tumor DNA in the Management of Patients With GI Stromal Tumor: Analysis of 243 Patients

PURPOSE

GI stromal tumor (GIST) is the most common sarcoma of the GI tract. Management of patients with GIST is determined by KIT, PDGFRA, or other genomic alterations. Tissue-based next-generation sequencing (NGS) analysis is the standard approach for diagnosis, prognosis, and treatment selection. However, circulating tumor DNA (ctDNA)–based NGS is a novel and noninvasive alternative.

METHODS

ctDNA sequencing results were evaluated in blood samples from 243 de-identified patients within the Guardant360 database. Under an approved institutional review board protocol, a retrospective analysis was performed on 45 single-institution patients.

RESULTS

Of 243 patients, 114 (47%) were women, and the median age was 59 years (range, 17-90 years). Patients with no alterations and variations of uncertain significance were excluded. Of the 162 patients with known pathogenic mutations, KIT was the most common (56%), followed by NF (7%), PDGFRA (6%), PI3KCA (6%), KRAS (5%), and others (6%). Most tumors harbored an actionable KIT or PDGFRA mutation. Our institutional cohort (n = 45) had 16 (35%) KIT exon 11 mutations, 3 (6%) KIT exon 9 mutations, and 1 (2%) PDGFRA mutation detected on ctDNA. Resistance mutations were observed in KIT exon 17 (8 patients), exon 13 (3 patients), and in both (3 patients). Our comparison of ctDNA with tissue NGS revealed a positive predictive value (PPV) of 100%. Failure of concordance was observed in patients with localized or low disease burden. From the time of ctDNA testing, the median overall survival was not reached, whereas the median progression-free survival was 7 months.

CONCLUSION

ctDNA provides a rapid, noninvasive analysis of current mutations with a high PPV for patients with metastatic GIST. ctDNA-based testing may help to define the optimal choice of therapy on the basis of resistance mutations and should be studied prospectively.

A comparison between the assessments of progression-free survival by local investigators versus blinded independent central reviews in phase III oncology trials

PURPOSE

In this study, we compared the assessments of progression-free survival (PFS) carried out by the local investigator or by a blinded independent central review in the framework of phase III registration randomized controlled trials (RCT) in oncology.

METHODS

We carried out a search in the clinicatrials.gov database, looking at the RCTs reporting the results of both independently assessed and investigator-assessed PFS. The hazard ratios (HRs) of investigator-assessed PFS and independently assessed PFS were recorded, and a discrepancy index was obtained by calculating the ratio of their respective HRs. Moreover, we investigated possible factors of discrepancy by analyzing the trials in different groups (by year, by tumor type, by drug type, by study design).

RESULTS

We analyzed 28 RCTs meeting the search criteria. The estimated mean discrepancy index was 0.98 (confidence interval 0.927-1.032 (n = 32)). Subgroup analysis showed that the confidence intervals in all cases included the value 1, except in the subgroup of studies started in the period 2003-2006.

CONCLUSION

In phase III oncology trials, we found no significant differences between the hazard ratios estimated by local investigators and those estimated by blinded independent central reviews. A relatively higher variability, in terms of large CI, was found in trials with biological agents.

Progress in determining response to treatment in gastrointestinal stromal tumor

Introduction: Gastrointestinal stromal tumor (GIST) is the most common malignant mesenchymal tumor of the gastrointestinal system. Multiple advances in the management of GIST from the discovery of KIT/PDGRA and other genetic alterations have led to the development of multiple tyrosine kinase inhibitors. Response assessment in GIST is determined with iRECIST (Response Evaluation Criteria in Solid Tumors), PERCIST (PET response criteria in solid tumors), or Choi criteria. Molecular genotyping of the tissue samples is the recent standard for diagnosis, treatment, and response to treatment.Areas covered: In this study, we provide a brief overview of the history of the GIST, molecular sequencing, available treatment options and clinical trials, radiologic response assessment, and the role of ctDNA in response evaluation.Expert opinion: Future GIST management is related to the development of sensitive assays to detect genetic alterations for initial diagnosis, treatment selection, monitoring the response to treatment, resistant mutations, and predicting survival.

Toxicity management of regorafenib in patients with gastro-intestinal stromal tumour (GIST) in a tertiary cancer centre

BACKGROUND

Regorafenib is a multi-kinase inhibitor approved as third line treatment for metastatic GIST. Dose limiting toxicities are frequently seen and many patients require dose reductions. This study aimed to evaluate regorafenib toxicities and their management in a real-world GIST population.

METHODS

Retrospective review of a prospectively maintained database identified 50 patients with GIST treated with regorafenib at our centre between March 2013 and September 2018.

RESULTS

Median progression free survival (PFS) was 7.7 months [interquartile range (IQR) 2.8-14.4 months]. Median overall survival (OS) from start of regorafenib to death or last follow up was 15.7 months (IQR 9.2-28.4 months). Baseline median Eastern Cooperative Oncology Group (ECOG) performance status on starting regorafenib was 1. The main reason for discontinuing regorafenib was progressive disease (PD) (31/50 [62%]) rather than toxicity (10/50 [20%]). Grade 3-4 adverse events (AEs) were seen in 23/50 (46%) patients; palmar-plantar erythrodysesthesia (PPE) was most frequently seen (9/50 (18%)). Two patients died whilst on treatment with regorafenib from multi-organ failure secondary to sepsis (4%). Dose reductions were required in 19/50 patients (38%) and 8/50 (16%) patients started regorafenib at a lower dose band than the recommended dose (160 mg) due to comorbidities or concern over a higher individual risk of toxicity.

CONCLUSION

Although PD was the main reason for discontinuing treatment, toxicity management and dosing of regorafenib remains critical. Median duration of treatment was longer compared to previous studies suggesting a durable clinical benefit with regorafenib with rigorous toxicity management.

Translational insights into gastrointestinal stromal tumor and current clinical advances

Gastrointestinal stromal tumor (GIST) is the most common soft tissue sarcoma of the gastrointestinal tract and, in the vast majority of cases, is characterized by activating mutations in KIT or, less commonly, PDGFRA. Mutations in these type III receptor tyrosine kinases (RTKs) account for over 85% of GIST cases, and the majority of KIT primary mutations respond to treatment with the tyrosine kinase inhibitor (TKI) imatinib. However, drug resistance develops over time, most commonly due to secondary kinase mutations. Sunitinib and regorafenib are approved for the treatment of imatinib-resistant GIST in the second and third lines, respectively. However, resistance to these agents also develops and new therapeutic options are needed. In addition, a small number of GISTs harbor primary activating mutations that are resistant to currently available TKIs, highlighting an additional unmet medical need. Several novel and selective TKIs that overcome known mechanisms of resistance in GIST have been developed and show promise in early clinical trials. Additional emerging targeted therapies in GIST include modulation of cellular signaling pathways downstream of KIT, antibodies targeting KIT and PDGFRA and immune checkpoint inhibitors. These advancements highlight the rapid evolution in the understanding of this malignancy and provide perspective on the encouraging horizon of current and forthcoming therapeutic strategies for GIST.

Association of Dasatinib With Progression-Free Survival Among Patients With Advanced Gastrointestinal Stromal Tumors Resistant to Imatinib

Importance

Gastrointestinal stromal tumors (GISTs) are life-threatening when metastatic or not amenable to surgical removal. In a few patients with advanced GISTs refractory to imatinib mesylate, treatment with sunitinib malate followed by regorafenib provides tumor control; however, additional active treatments are needed for most patients.

Objective

To evaluate the 6-month progression-free survival (PFS), tumor objective response, and overall survival rates in patients with GISTs treated with dasatinib.

Design, Setting, and Participants

This single-arm clinical trial used a Bayesian design to enroll patients 13 years or older with measurable imatinib-refractory metastatic GISTs treated at 14 sarcoma referral centers from June 1, 2008, through December 31, 2009. A control group was not included. Patients were followed up for survival for a minimum of 5 years from date of enrollment. Tumor imaging using computed tomography or magnetic resonance imaging was performed every 8 weeks for the first 24 weeks and every 12 weeks thereafter. Tumor response was assessed by local site using the Choi criteria. Treatment was continued until tumor progression, unacceptable toxic effects after reduction in drug dose, or patient or physician decision. Archival tumor tissue was evaluated for expression of the proto-oncogene tyrosine-protein kinase Src (SRC), phosphorylated SRC (pSRC), and succinate dehydrogenase complex iron sulfur subunit B (SDHB) proteins and for mutation in the V-Kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog (KIT) and platelet-derived growth factor receptor α (PDGFRA) genes. Data analysis was performed from May 19, 2017, through December 20, 2017.

Interventions

Dasatinib, 70 mg orally twice daily.

Main Outcomes and Measures

The primary end point was the 6-month PFS estimate using greater than 30% as evidence of an active drug and less than 10% as evidence of inactive treatment.

Results

In this study, 50 patients were enrolled (median age, 60 years; age range, 19-78 years; 31 [62%] male and 19 [38%] female; 41 [82%] white), and 48 were evaluable for response. The estimated 6-month PFS rate was 29% in the overall population and 50% in a subset of 14 patients with pSRC in GISTs. Objective tumor response was observed in 25%, including 1 patient with an imatinib-resistant mutation in PDGFRA exon 18.

Conclusions and Relevance

Dasatinib may have activity in a subset of patients with imatinib-resistant GISTs. Further study is needed to determine whether pSRC is a prognostic biomarker.

Targeted therapy and personalized medicine in gastrointestinal stromal tumors: drug resistance, mechanisms, and treatment strategies

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the gastrointestinal tract. Since the discovery that the KIT and PDGFRA receptor tyrosine kinases are the primary oncogenic drivers in the vast majority of GISTs, targeted therapy with tyrosine kinase inhibitors has been the mainstay of treatment for this disease. Using molecular profiling of tumor specimens, researchers also discovered that KIT and PDGFRA mutations are non-random and occur in specific regions of the receptors, and furthermore, that particular genotypes predicted response or resistance to targeted therapy. Imatinib, the first tyrosine kinase inhibitor used to treat GIST, remains the first-line therapy in advanced GIST and the only therapy confirmed through clinical trials in the adjuvant or neoadjuvant setting for resectable disease. Resistance to imatinib is well described and is either primary or secondary. Primary resistance is associated with specific tumor genotypes, so genotyping of individual patient tumors helps guide decision-making into whether to offer imatinib and at what dose. Secondary resistance occurs due to the acquisition of secondary mutations during therapy. Currently, the main strategy to combat imatinib resistance is to switch to another tyrosine kinase inhibitor, because imatinib-resistant GIST is usually still oncogenically addicted to KIT/PDGFRA signaling. Surgery can also be used to combat resistant disease in select settings. Unfortunately, progression-free and overall survival remains dismal for patients who develop imatinib-resistant disease, and further research into alternative strategies is still needed.

Apatinib Treatment in Metastatic Gastrointestinal Stromal Tumor

Background: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. The clinical management of patients with metastatic GISTs is exceptionally challenging due to their poor prognosis. Apatinib is a multiple tyrosine kinase inhibitor. Here, we present the unique case with metastatic GISTs who derived clinical benefit from apatinib following the failure of imatinib and sunitinib. Case presentation: A 57-year-old man was admitted to our hospital diagnosed with metastatic and recurrent GISTs following surgical resection. Fifty-four months after the first-line imatinib treatment, he developed progressive disease and then was treated with cytoreductive surgery combined with imatinib. Disease progression occurred after 7 months. He then received second-line sunitinib and achieved a progression-free survival of 11 months. Apatinib mesylate was then administered. Follow-up imaging revealed a stable disease. Progression-free survival following apatinib therapy was at least 8 months. The only toxicities were hypertension and proteinuria, which were both controllable and well-tolerated. Conclusions: Treatment with apatinib provides an additional option for the treatment of patients with GISTs refractory to imatinib and sunitinib.

Real-World Evidence of Patient Outcome Following Treatment of Advanced Gastrointestinal Stromal Tumor (GIST) with Imatinib, Sunitinib, and Sorafenib in Publicly Funded Health Care in Poland

Background

This study aimed to undertake an analysis of ten years of real-world evidence (RWE) on overall survival (OS) following treatment of advanced gastrointestinal stromal tumor (GIST) with imatinib, sunitinib, and sorafenib using data from the Polish National Health Fund.

Material/Methods

Data from the Polish National Health Fund, the sole Polish public payer, identified 1,641 patients with advanced GIST who were treated with imatinib (n=1047), sunitinib (n=457), and sorafenib (n=137). The differences in overall survival (OS) were analyzed.

Results

For patients with advanced GIST, the median follow-up time for patients treated with imatinib was 71 months (95% CI, 64.8–79.2), the median OS was 56.9 months (95% CI, 50.4–61.2), with survival at 12 months (89.5%), 24 months (77.9%), 36 months (66.9%), and 60 months (48.4%). The median follow-up time for patients treated with sunitinib was 41.4 months (95% CI, 34.6–49.3), the median OS was 22.8 months (95% CI, 19.2–26.8), with survival at 12 months (68.2%), 24 months (47.1%), and 36 months (31%). The median follow-up time for patients treated with sorafenib was 17.4 months (95% CI, 14.6–22.9), the median OS was 16.9 months (95% CI, 13.7–24.3), with survival at 12 months (61.9%), at 24 months (36.2%), and at 36 months (16.8%).

Conclusions

Real-world data collected in a ten-year period confirmed the effectiveness of the use of imatinib, sunitinib, or sorafenib for the treatment of advanced GIST and was comparable with the findings from clinical trials.

New frontiers in the medical management of gastrointestinal stromal tumours

The tyrosine kinase inhibitor (TKI) imatinib has radically changed the natural history of KIT-driven gastrointestinal stromal tumours (GISTs). Approved second-line and third-line medical therapies are represented by the TKIs sunitinib and regorafenib, respectively. While imatinib remains the cardinal drug for patients with GISTs, novel therapies are being developed and clinically tested to overcome the mechanisms of resistance after treatments with the approved TKI, or to treat subsets of GISTs driven by rarer molecular events. Here, we review the therapy of GISTs, with a particular focus on the newest drugs in advanced phases of clinical testing that might soon change the current therapeutic algorithm.

Making progress in a rare disease: emerging therapeutics in soft tissue sarcomas

Sarcomas are rare tumors derived from mesenchymal connective tissues in the body. Because there are well over 50 histologic sarcoma subtypes, including malignant and non-malignant pathologies, clinical courses and therapeutic management are widely divergent. In general, therapeutic options across all soft tissue sarcomas are limited in number and are often generalized across multiple sarcoma histologies. The recent emergence of molecularly targeted therapies and immune-based agents presents a future of refined systemic treatment practices that are rationally tailored to the tumor by histologic subtype and biologic mechanisms.

Systematic bias between blinded independent central review and local assessment: literature review and analyses of 76 phase III randomised controlled trials in 45 688 patients with advanced solid tumour

OBJECTIVE

Unbiased assessment of tumour response is crucial in randomised controlled trials (RCTs). Blinded independent central review is usually used as a supplemental or monitor to local assessment but is costly. The aim of this study is to investigate whether systematic bias existed in RCTs by comparing the treatment effects of efficacy endpoints between central and local assessments.

DESIGN

Literature review, pooling analysis and correlation analysis.

DATA SOURCES

PubMed, from 1 January 2010 to 30 June 2017.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Eligible articles are phase III RCTs comparing anticancer agents for advanced solid tumours. Additionally, the articles should report objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS) or time to progression (TTP); the treatment effect of these endpoints, OR or HR, should be based on central and local assessments.

RESULTS

Of 76 included trials involving 45 688 patients, 17 (22%) trials reported their endpoints with statistically inconsistent inferences (p value lower/higher than the probability of type I error) between central and local assessments; among them, 9 (53%) trials had statistically significant inference based on central assessment. Pooling analysis presented no systematic bias when comparing treatment effects of both assessments (ORR: OR=1.02 (95% CI 0.97 to 1.07), p=0.42, I2=0%; DCR: OR=0.97 (95% CI 0.92 to 1.03), p=0.32, I2=0%); PFS: HR=1.01 (95% CI 0.99 to 1.02), p=0.32, I2=0%; TTP: HR=1.04 (95% CI 0.95 to 1.14), p=0.37, I2=0%), regardless of funding source, mask, region, tumour type, study design, number of enrolled patients, response assessment criteria, primary endpoint and trials with statistically consistent/inconsistent inferences. Correlation analysis also presented no sign of systematic bias between central and local assessments (ORR, DCR, PFS: r>0.90, p<0.01; TTP: r=0.90, p=0.29).

CONCLUSIONS

No systematic bias could be found between local and central assessments in phase III RCTs on solid tumours. However, statistically inconsistent inferences could be made in many trials between both assessments.

Role of surgical resection for patients with recurrent or metastatic gastrointestinal stromal tumors: A systematic review and meta-analysis

BACKGROUND

The role of surgical resection for patients with recurrent or metastatic gastrointestinal stromal tumors is still controversial. This meta-analysis aims to investigate the clinical outcomes of surgery combined with tyrosine kinase inhibitors among patients with recurrent or metastatic gastrointestinal stromal tumors.

METHODS

We systematically searched PubMed, EMBASE, the Cochrane Library and Wanfangdata without language restriction. Random effect models were used to estimate pooled hazard ratio and the corresponding 95% confidence intervals. Subgroup analyses, sensitivity analysis and trim and fill analysis were also performed.

RESULTS

A total of 1416 patient from 9 studies were finally enrolled in this meta-analysis. The summary results showed that surgery combined with tyrosine kinase inhibitors showed a tendency of a longer overall survival compared with tyrosine kinase inhibitors treatment alone (HR by random-effects model 0.68, 95% CI 0.54-0.85, I2 = 44.7%) and improved progress-free survival (HR by random-effects model 0.50,95% CI, 0.33-0.76, I2 = 17.9%). The trim and fill analysis and sensitive analysis indicated the relatively robust result.

CONCLUSION

Surgery combined with tyrosine kinase inhibitors therapy is associated with a better overall survival and progression free survival for patients with recurrent or metastatic gastrointestinal stromal tumors as compared with TKIs treatment alone.

Advances and Challenges on Management of Gastrointestinal Stromal Tumors

Gastrointestinal stromal tumors (GISTs) originate from interstitial cells of Cajal and account for over 5,000 newly diagnosed cases in the United States. The discovery of activated KIT and PDGFRA mutations and introduction of imatinib revolutionized the treatment strategy and opened up the new era of target therapy for solid tumors. Although surgery remains the primary modality of treatment for curative purpose, almost half of the patients experienced disease recurrence. Tailoring (neo)-adjuvant treatment with imatinib is ongoing to meet the need for an effective therapy. Currently, two drugs (sunitinib and regorafenib) have obtained Food and Drug Administration approval for GISTs after imatinib failure. However, most of the patients eventually progress due to primary or secondary resistance. Deeper understanding of the molecular mechanisms will guide us to develop personalized strategies in the future. Discussion in this review includes current standard management and the most recent advances and multiple ongoing clinical trials with different approaches. This review will provide further steps to be taken to conquer refractory disease.

CD117/c-kit in Cancer Stem Cell-Mediated Progression and Therapeutic Resistance

Metastasis is the primary cause of cancer patient morbidity and mortality, but due to persisting gaps in our knowledge, it remains untreatable. Metastases often occur as patient tumors progress or recur after initial therapy. Tumor recurrence at the primary site may be driven by a cancer stem-like cell or tumor progenitor cell, while recurrence at a secondary site is driven by metastatic cancer stem cells or metastasis-initiating cells. Ongoing efforts are aimed at identifying and characterizing these stem-like cells driving recurrence and metastasis. One potential marker for the cancer stem-like cell subpopulation is CD117/c-kit, a tyrosine kinase receptor associated with cancer progression and normal stem cell maintenance. Further, activation of CD117 by its ligand stem cell factor (SCF; kit ligand) in the progenitor cell niche stimulates several signaling pathways driving proliferation, survival, and migration. This review examines evidence that the SCF/CD117 signaling axis may contribute to the control of cancer progression through the regulation of stemness and resistance to tyrosine kinase inhibitors.

A systematic review and network meta-analysis of post-imatinib therapy in advanced gastrointestinal stromal tumour

Background

The standard first-line systemic therapy for advanced gastrointestinal stromal tumour (gist) is imatinib. However, most gists develop imatinib resistance, highlighting the need for new agents in the imatinib-refractory setting. Currently, no randomized studies have directly compared the available post-first-line treatments.

Methods

In a systematic review, the medline, embase, and central databases, and American Society of Clinical Oncology abstracts to July 2014 were searched to identify randomized controlled trials that included gist patients treated with post-first-line therapies. Hazard ratios (hrs) for progression-free (pfs) and overall survival (os) were extracted. Direct pairwise meta-analyses and indirect comparisons using the Butcher method were performed.

Results

Four studies were identified for the systematic review. One study showed that sunitinib in the second-line setting (vs. placebo) was associated with improved pfs, but not improved os. Three studies examined the third-line setting (imatinib resumption vs. placebo, regorafenib vs. placebo, nilotinib vs. best supportive care). In the third-line settings, the two placebo-controlled and the non-placebo-controlled trials showed significant heterogeneity (I² = 98%). Indirect comparisons of imatinib resumption and regorafenib suggested that the hr for pfs was 0.59 (95% confidence interval: 0.31 to 1.12; p = 0.10), trending in favour of regorafenib. Indirect comparisons found that toxicities were higher in the regorafenib group, with a risk difference of 27.8% for any-grade toxicities and 19.5% for grades 3 and 4 toxicities.

Conclusions

Because a head-to-head study of imatinib resumption compared with regorafenib is unlikely ever to be conducted, our study suggests that, in terms of pfs, regorafenib might be the preferred treatment. However, given the increased toxicity observed with regorafenib, clinicians should interpret that evidence with caution at an individual patient level.

Recurrent Gastrointestinal Stromal Tumors in the Imatinib Mesylate Era: Treatment Strategies for an Incurable Disease

Introduction

Recurrence of gastrointestinal stromal tumors (GISTs) after surgical resection and imatinib mesylate (IM) adjuvant therapy poses a significant treatment challenge. We present the case of a patient who underwent surgical resection after recurrence and review the current literature regarding treatment.

Case Presentation

A 58-year-old man with a large intra-abdominal jejunal GIST was treated with complete surgical resection followed by IM. The patient experienced disease recurrence 3.5 years later and underwent IM dose escalation and reresection.

Conclusion

Current strategies to treat recurrent GIST include dose escalation, modifying adjuvant tyrosine kinase inhibitor therapy, and surgery. High-level evidence will be required to better define the combinatory roles of tyrosine kinase inhibitor therapy, guided by molecular profiling, and surgery in the management of recurrent GIST.

Effect of silencing TEM8 gene on proliferation, apoptosis, migration and invasion of XWLC‑05 lung cancer cells

Currently, the role of tumor endothelial marker 8 (TEM8) in the occurrence, development, invasion and metastasis of lung cancer and its mechanism are poorly understood. The present study aimed to investigate the effects of TEM8 on proliferation, apoptosis, migration and invasion of XWLC-05 lung cancer cells. The expression of TEM8 in human lung cancer and adjacent tissues was detected by reverse transcription-quantitative polymerase chain reaction and western blotting. An interference vector coding a short hairpin RNA (shRNA) targeting TEM8 was designed and transfected into XWLC-05 lung cancer cells. MTT assay was used to detect cell proliferation. Flow cytometry was employed to detect cell cycle and apoptosis. Cell scratch assay was used for cell migration detection. Cell invasion ability was detected by the Transwell method. The expression of TEM8 in lung cancer tissues was significantly increased compared with adjacent tissues (P<0.05). Following the silencing of TEM8 by shRNA interference, cell proliferation was inhibited and the apoptosis rate increased. The cell cycle was arrested at G1 phase, while the migration and invasion ability of cancer cells was decreased. Silencing TEM8 may inhibit proliferation of XWLC-05 lung cancer cells, promote cell apoptosis, arrest the cell cycle at G1 phase and decrease the migration and invasive ability. Thus, TEM8 may be a potential target in therapy for lung cancer.

Randomized Clinical Trials in Gastrointestinal Stromal Tumors

This review explores the current standard of care for the surgical management of gastrointestinal stromal tumors, highlights important studies in the medical management of gastrointestinal stromal tumors, and provides guidance in how these studies changed the standard of care in clinical practice.

Unravelling the pharmacologic opportunities and future directions for targeted therapies in gastro-intestinal cancers part 2: Neuroendocrine tumours, hepatocellular carcinoma, and gastro-intestinal stromal tumours

Until the 1990s, cytotoxic chemotherapy has been the cornerstone of medical therapy for gastrointestinal (GI) cancers. Better understanding of the cancer cell molecular biology has led to the therapeutic revolution of targeted therapies, i.e. monoclonal antibodies or small molecule inhibitors directed against proteins that are specifically overexpressed or mutated in cancer cells. These agents, being more specific to cancer cells, were expected to be less toxic than conventional cytotoxic agents. However, their effects have sometimes been disappointing, due to intrinsic or acquired resistance mechanisms, or to an activity restricted to some tumour settings, illustrating the importance of patient selection and early identification of predictive biomarkers of response to these therapies. Targeted agents have provided clinical benefit in many GI cancer types. Particularly, some GI tumours are considered chemoresistant and targeted therapies have offered a new therapeutic base for their management. Hence, somatostatin receptor-directed strategies, sorafenib, and imatinib have revolutioned the management of neuroendocrine tumours (NET), hepatocellular carcinoma (HCC), and gastrointestinal stromal tumours (GIST), respectively, and are now used as first-line treatment in many patients affected by these tumours. However, these agents face problems of resistances and identification of predictive biomarkers from imaging and/or biology. We propose a comprehensive two-part review providing a panoramic approach of the successes and failures of targeted agents in GI cancers to unravel the pharmacologic opportunities and future directions for these agents in GI oncology. In this second part, we will focus on NET, HCC, and GIST, whose treatment relies primarily on targeted therapies.