Efficacy of sorafenib in patients with gastrointestinal stromal tumors in the third- or fourth-line treatment: A retrospective multicenter experience

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.

An updated review of the treatment landscape for advanced gastrointestinal stromal tumors

Before the introduction of tyrosine kinase inhibitors (TKIs), the overall survival of patients with advanced or metastatic gastrointestinal stromal tumors (GISTs) was 10 to 20 months because of the lack of approved therapies. In the last 20 years, a treatment algorithm for patients with advanced GISTs, which includes imatinib, sunitinib, and regorafenib as first‐, second‐, and third‐line therapies, respectively, has been established. Recently, 2 new TKIs have been approved: ripretinib for fourth‐line therapy and avapritinib as first‐line therapy in patients harboring platelet‐derived growth factor receptor α (PDGFRA) exon 18 D842V mutations. Additionally, there are several experimental therapies under investigation that could advance individualized patient care. All of these therapies have varying efficacies and safety profiles that warrant an updated treatment landscape review. This review article summarizes the efficacy and safety data currently available for conventional TKIs along with recently approved and experimental therapies.

With evolving treatment options and effective toxicity management, patients with advanced gastrointestinal stromal tumors are living longer than ever before. Recently approved targeted therapies and the investigation of experimental treatment options have the potential to alter the current treatment algorithm and encourage personalized patient care.

Kinase inhibitors with viral oncolysis: Unmasking pharmacoviral approaches for cancer therapy

There are more than 500 kinases in the human genome, many of which are oncogenic once constitutively activated. Fortunately, numerous hyperactive kinases are druggable, and several targeted small molecule kinase inhibitors have demonstrated impressive clinical benefits in cancer treatment. However, their often cytostatic rather than cytotoxic effect on cancer cells, and the development of resistance mechanisms, remain significant limitations to these targeted therapies. Oncolytic viruses are an emerging class of immunotherapeutic agents with a specific oncotropic nature and excellent safety profile, highlighting them as a promising alternative to conventional therapeutic modalities. Nonetheless, the clinical efficacy of oncolytic virotherapy is challenged by immunological and physical barriers that limit viral delivery, replication, and spread within tumours. Several of these barriers are often associated with oncogenic kinase activity and, in some cases, worsened by the action of oncolytic viruses on kinase signaling during infection. What if inhibiting these kinases could potentiate the cancer-lytic and anti-tumour immune stimulating properties of oncolytic virotherapies? This could represent a paradigm shift in the use of specific kinase inhibitors in the clinic and provide a novel therapeutic approach to the treatment of cancers. A phase III clinical trial combining the oncolytic Vaccinia virus Pexa-Vec with the kinase inhibitor Sorafenib was initiated. While this trial failed to show any benefits over Sorafenib monotherapy in patients with advanced liver cancer, several pre-clinical studies demonstrate that targeting kinases combined with oncolytic viruses have synergistic effects highlighting this strategy as a unique avenue to cancer therapy. Herein, we review the combinations of oncolytic viruses with kinase inhibitors reported in the literature and discuss the clinical opportunities that represent these pharmacoviral approaches.

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.

The analysis of the long-term outcomes of sorafenib therapy in routine practice in imatinib and sunitinib resistant gastrointestinal stromal tumors (GIST)

Aim of the study

was to analyze the outcome of treatment and factors predicting results of sorafenib therapy in inoperable/metastatic CD117-positive GIST patients after failure on imatinib and sunitinib.

Material and methods

We identified 60 consecutive patients (40 men, 20 women) with advanced inoperable/metastatic GIST after failure on at least imatinib and sunitinib treated in one sarcoma center with sorafenib at initial dose 2 × 400 mg daily in 2007-2015 (in 56 cases it was 3^rd line therapy). Median follow-up time was 39 months.

Results

One year progression-free survival (PFS; calculated from the date of the start of sorafenib to disease progression) rate was 23% and median PFS = 7.7 months. The median overall survival (OS) was 13.5 months calculated from sorafenib start (1-year OS rate = 57%) and 7 years from imatinib start. Three patients (5%) had objective partial responses to therapy, 31 patients (52%) had stabilization of disease > 4 months. Primary tumor mutational status was known in 43 cases (73%), but we have not identified the differences in PFS between tumors carrying different KIT/PDGFRA mutations. The most common adverse events were: diarrhoea, hand and foot syndrome, fatigue, loss of weight and skin reactions; grade 3-5 toxicity occurred in 35% of patients. 23 patients required sorafenib dose reductions due to AEs.

Conclusions

We confirmed that many advanced GIST patients benefit from sorafenib therapy after imatinib/sunitinib failure with OS > 1 year.

Surgical Pathology of Gastrointestinal Stromal Tumors: Practical Implications of Morphologic and Molecular Heterogeneity for Precision Medicine

Gastrointestinal stromal tumor (GIST), the most common mesenchymal neoplasm of the gastrointestinal tract, exhibits diverse histologic and clinical manifestations. With its putative origin in the gastrointestinal pacemaker cell of Cajal, GIST can arise in association with any portion of the tubular gastrointestinal tract. Morphologically, GISTs are classified as spindled or epithelioid, though each of these subtypes encompasses a broad spectrum of microscopic appearances, many of which mimic other histologic entities. Despite this morphologic ambiguity, the diagnosis of GIST is aided in many cases by immunohistochemical detection of KIT (CD117) or DOG1 expression. The natural history of GIST ranges from that of a tumor cured by surgical resection to that of a locally advanced or even widely metastatic, and ultimately fatal, disease. This clinicopathologic heterogeneity is paralleled by an underlying molecular diversity: the majority of GISTs are associated with spontaneous activating mutations in KIT, PDGFRA, or BRAF, while additional subsets are driven by genetic lesions-often inherited-of NF1 or components of the succinate dehydrogenase enzymatic complex. Specific gene mutations correlate with particular anatomic or morphologic characteristics and, in turn, with distinct clinical behaviors. Therefore, prognostication and treatment are increasingly dictated not only by morphologic clues, but also by accompanying molecular genetic features. In this review, we provide a comprehensive description of the heterogenous molecular underpinnings of GIST, including implications for the practicing pathologist with regard to morphologic identification, immunohistochemical diagnosis, and clinical management.

An Unusual Case of Central Retinal Vein Occlusion and Review of the Toxicity Profile of Regorafenib in GIST Patients

Gastrointestinal stromal tumor (GIST) is the most common sarcoma of the gastrointestinal tract with around 5000 new cases per year. Outcomes for patients with GIST dramatically improved after the development of tyrosine kinase inhibitors targeted against the aberrant signaling pathways that drive GIST oncogenesis. Majority of patients derive benefit from first-line imatinib, and the type of driver mutation is predictive of response. However, almost half of the patients eventually develop resistance to initial targeted therapy and further lines of treatment do not have the same impact. Regorafenib is an oral multi-kinase inhibitor approved as a third-line therapy for advanced GIST and though its efficacy is limited in comparison to imatinib, it has activity across the various driver mutation categories in GIST even in the setting of imatinib resistance. Herein, we describe a case of central retinal vein occlusion (CRVO) secondary to regorafenib and review regorafenib's efficacy and toxicity profile.

Contemporary Management of Metastatic Gastrointestinal Stromal Tumors: Systemic and Locoregional Approaches

The treatment of metastatic gastrointestinal stromal tumors (GISTs) changed dramatically with the introduction of imatinib into the therapeutic lexicon in 2001. Over the past 15 years, tyrosine kinase inhibitors in the adjuvant and metastatic settings have remained the standard of care for this disease, though alternate classes of agents and new therapeutic targets are being actively explored in clinical trials. Although data are limited, the use of surgical and non-surgical locoregional techniques for the treatment of GIST metastases has increased and given reports of promising and durable responses. Herein we provide an overview of the contemporary therapeutic landscape of metastatic GIST.