Systemic therapy options for advanced gastrointestinal stromal tumors beyond first-line imatinib: a systematic review

Cell-permeable PI3 kinase competitive peptide inhibits KIT mutant mediated tumorigenesis of gastrointestinal stromal tumor (GIST)

BACKGROUND

Mutations in the receptor tyrosine kinase KIT are the main cause of gastrointestinal stromal tumor (GIST), and the KIT mutants mediated PI3 kinase activation plays a key role in the tumorigenesis of GIST. In this study, we aimed to block PI3 kinase activation by cell-permeable peptide and investigate its possible application in the treatment of GIST.

METHODS AND RESULTS

We designed cell-permeable peptides based on the binding domain of PI3 kinase subunit p85 to KIT or PI3 kinase subunit p110, respectively, in order to compete for the binding between p85 and KIT or p110 and therefore inhibit the activation of PI3 kinases mediated by KIT. The results showed that the peptide can penetrate the cells, and inhibit the activation of PI3 kinases, leading to reduced cell survival and cell proliferation mediated by KIT mutants in vitro. Treatment of mice carrying germline KIT/V558A mutation, which can develop GIST, with the peptide that can compete for the binding between p85 and p110, led to reduced tumorigenesis of GIST. The peptide can further enhance the inhibition of the tumor growth by imatinib which is used as the first line targeted therapy of GIST.

CONCLUSIONS

Our results showed that cell-permeable PI3 kinase competitive peptide can inhibit KIT-mediated PI3 kinase activation and tumorigenesis of GIST, providing a rationale to further test the peptide in the treatment of GIST and even other tumors with over-activation of PI3 kinases.

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.

Targeted Cancer Therapy: What's New in the Field of Neuroendocrine Neoplasms?

Neuroendocrine tumors (NETs) are a heterogeneous family of neoplasms of increasing incidence and high prevalence due to their relatively indolent nature. Their wide anatomic distribution and their characteristic ability to secrete hormonally active substances pose unique challenges for clinical management. They are also characterized by the common expression of somatostatin receptors, a target that has been extremely useful for diagnosis and treatment (i.e., somatostatin analogues (SSAs) and peptide-receptor radionuclide therapy (PRRT)). Chemotherapy is of limited use for NETs of non-pancreatic origin, and the only approved targeted agents for advanced progressive NETs are sunitinib for those of pancreatic origin, and everolimus for lung, gastrointestinal and pancreatic primaries. Despite recent therapeutic achievements, thus, systemic treatment options remain limited. In this review we will discuss the state-of-the-art targeted therapies in the field of NETs, and also future perspectives of novel therapeutic drugs or strategies in clinical development, including recently presented results from randomized trials of yet unapproved antiangiogenic agents (i.e., pazopanib, surufatinib and axitinib), PRRT including both approved radiopharmaceuticals (177Lu-Oxodotreotide) and others in development (177Lu-Edotreotide, 177Lu-Satoreotide Tetraxetan), immunotherapy and other innovative targeted strategies (antibody-drug conjugates, bites,…) that shall soon improve the landscape of personalized treatment options in NET patients.

Loss of PI3 kinase association improves the sensitivity of secondary mutation of KIT to Imatinib

Background

KIT mutations are the predominant driver mutations in gastrointestinal stromal tumors (GISTs), and targeted therapy against KIT has improved treatment outcome dramatically. However, gaining secondary mutation of KIT confers drug resistance of GISTs leading to treatment failure.

Results

In this study, we found that secondary mutation of KIT dramatically increases the ligand-independent activation of the receptor and their resistance to the often used KIT inhibitor Imatinib in the treatment of GISTs. PI3 kinase plays essential roles in the cell transformation mediated by the primary mutation of KIT. We found that loss of PI3 kinase association, but not the inhibition of the lipid kinase activity of PI3 kinase, inhibits the ligand-independent activation of secondary mutations of KIT, and increases their sensitivity to Imatinib, and loss of PI3 kinase association inhibits secondary mutations of KIT mediated cell survival and proliferation in vitro. The in vivo assay further showed that the growth of tumors carrying secondary mutations of KIT is more sensitive to Imatinib when PI3 kinase association is blocked while inhibition of the lipid kinase activity of PI3 kinase cannot inhibit tumor growth, indicating that PI3 kinase is important for the drug resistance of secondary mutation of KIT independent of the lipid kinase activity of PI3 kinase.

Conclusions

Our results suggested that PI3 kinase is necessary for the ligand-independent activation of secondary mutations of KIT, and loss of PI3 kinase association improves the sensitivity of secondary mutations to the targeted therapy independent of the lipid kinase activity of PI3 kinase.

Safety of Imatinib Mesylate in a Multicenter Expanded Access Program in Adult Patients with Gastrointestinal Stromal Tumors in the Adjuvant Setting

BACKGROUND

Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors most often caused by activating mutations of the KIT gene. KIT tyrosine kinase inhibitors provide targeted therapy for the underlying genetic mutation, and adjuvant therapy is indicated for patients who are at significant risk of relapse following GIST resection. This is a report of the safety of imatinib in patients with GIST in the adjuvant setting in an expanded access program.

METHODS

In this multicenter, open-label, single-arm trial, safety was assessed based on the frequency of adverse events (AEs).

RESULTS

Three hundred patients were treated and analyzed; 40 patients discontinued treatment. Median overall exposure during the program was 181 days (range 9-420); most patients (260/300 treated) completed the study. Six patients had disease recurrence, 4 of whom discontinued. In line with previously published reports, the most frequent AEs were nausea, diarrhea, and periorbital edema. The AEs were mild to moderate in most cases (76%).

CONCLUSIONS

These findings are in agreement with the known safety profile of imatinib and confirm the safety of imatinib at 400 mg/day in the adjuvant setting. The incidence of severe AEs was low.

Comparison of three prognostic models for predicting cancer-specific survival among patients with gastrointestinal stromal tumors

AIM

To evaluate the predictive value for cancer-specific survival of the models of the American Joint Committee on Cancer (AJCC) stage, NIH and Armed Forces Institute of Pathology (AFIP) among patients with gastrointestinal stromal tumors (GISTs).

METHODS

Surveillance, Epidemiology and End Results database (2010-2014) was accessed. Overall survival analysis and adjusted cancer-specific Cox regression hazard was calculated.

RESULTS

For gastric GISTs, concordance-index according to AJCC was 0.834; according to NIH was 0.833; according to AFIP was 0.836. Concordance-index for nongastric GISTs according to AJCC was 0.800, according to NIH was 0.801 and according to AFIP was 0.799.

CONCLUSION

The performance of the three models is comparable with regards to cancer-specific survival prediction.

Evidence mapping based on systematic reviews of therapeutic interventions for gastrointestinal stromal tumors (GIST)

Background

Gastrointestinal Stromal Tumours (GISTs) are the most common mesenchymal tumours. Currently, different pharmacological and surgical options are used to treat localised and metastatic GISTs, although this research field is broad and the body of evidence is scattered and expanding. Our objectives are to identify, describe and organise the current available evidence for GIST through an evidence mapping approach.

Methods

We followed the methodology of Global Evidence Mapping (GEM). We searched Pubmed, EMBASE, The Cochrane Library and Epistemonikos in order to identify systematic reviews (SRs) with or without meta-analyses published between 1990 and March 2016. Two authors assessed eligibility and extracted data. Methodological quality of the included systematic reviews was assessed using AMSTAR. We organised the results according to identified PICO questions and presented the evidence map in tables and a bubble plot.

Results

A total of 17 SRs met eligibility criteria. These reviews included 66 individual studies, of which three quarters were either observational or uncontrolled clinical trials. Overall, the quality of the included SRs was moderate or high. In total, we extracted 14 PICO questions from them and the corresponding results mostly favoured the intervention arm.

Conclusions

The most common type of study used to evaluate therapeutic interventions in GIST sarcomas has been non-experimental studies. However, the majority of the interventions are reported as beneficial or probably beneficial by the respective authors of SRs. The evidence mapping is a useful and reliable methodology to identify and present the existing evidence about therapeutic interventions.

Electronic supplementary material

The online version of this article (doi:10.1186/s12874-017-0402-9) contains supplementary material, which is available to authorized users.

[Clinical and pathological features of gastrointestinal stromal tumors (GIST) in a single institution: A descriptive study and review of the literature]

INTRODUCTION

This study was aimed to assess the main clinical, pathological and therapeutic characteristics of a cohort of gastrointestinal stromal tumors (GIST).

METHODS

Observational study including 66 patients diagnosed with GIST admitted to our hospital between 2002 and 2015. Parameters related to medical history, clinical manifestations, medical and surgical treatment, histopathology, and morbi-mortality were studied. A review of the literature was included to correlate with the results.

RESULTS

The most frequent location of GIST in our patients was the stomach (65.2%), in which the gastric fondo was the predominant region. The most common clinical manifestation was gastrointestinal hemorrhage (45.5%), followed by incidental finding after imaging or invasive procedures (33.3%). 58 patients underwent surgery (90.6%), 15.5% were urgent. A total of 69% of the GISTs had a size between 2 and 10cm. The one-year mortality was 7.9%, all cases related to local or remote extension, or surgical complications.

CONCLUSION

There is a large clinical variability among GIST cases. The first choice of treatment is surgery, which is feasible in most cases and should be as conservative as possible. The prognosis varies depending on the size and proliferation index, thus close follow-up should be performed. No tumor marker is clearly associated with a poor prognosis. New molecular biology studies are needed in order to find therapeutic targets.

Novel investigational therapies for treating biliary tract carcinoma

INTRODUCTION

Cholangiocarcinoma (CCA) is an epithelial cell malignancy arising from bile ducts and/or peribiliary glands. Even though it is considered as a rare neoplasm, its incidence is raising, particularly in developed countries. Prognosis is generally poor with few patients who present the inclusion criteria for surgery (the mainstay treatment for this tumour). Several genetic alterations potentially driving tumour progression have been described, representing a possible target for new compounds. Areas covered: A clinical trial search in Clinicaltrials.gov encompassing a literature search in PubMed and ASCO/ESMO Websites was undertaken in March 2016. Expert opinion: Notwithstanding a large number of drug tested, results are still disappointing. The main reasons could be the low number of patients enrolled in trials, and the lack of a patient selection based on the biological profile of the tumours. Potential active drugs could have been discharged simply because beneficial in a particular subgroup of patients and not in un unselected population. The future direction of the research should consider biomarker evaluation in order to describe the genetic alteration/s that drive tumour progression and aggressiveness and the mechanisms of drug resistance. Finally, it will be of great interest to consider the results of immunotherapy whenever available.

Adverse events associated with tyrosine kinase inhibitors for the treatment of chronic myeloid leukemia

INTRODUCTION

Tyrosine kinase inhibitors (TKIs) drastically changed the outcome of patients affected by chronic myeloid leukemia, allowing long-term improved overall survival and deep molecular responses.

AREAS COVERED

In this review, all the related and "off target" side effects of different TKIs are reported and reviewed including their pathogenesis, and associated predisposing factors are discussed.

EXPERT OPINION

Appropriate identification of adverse events and classification according to CTC scale is required during therapy with TKI, considering the impact on the long-term quality of life. Specific evaluation and stratification of comorbidities and cardiovascular risk profile at baseline is suggested in order to better tailor individualized treatment strategy and identify patients who require strict monitoring of risk factors during treatment.