Impact of rechallenge with imatinib in patients with advanced gastrointestinal stromal tumor after failure of imatinib and sunitinib

English version of Japanese Clinical Practice Guidelines 2022 for gastrointestinal stromal tumor (GIST) issued by the Japan Society of Clinical Oncology

The Japan Society of Clinical Oncology Clinical Practice Guidelines 2022 for gastrointestinal stromal tumor (GIST) have been published in accordance with the Minds Manual for Guideline Development 2014 and 2017. A specialized team independent of the working group for the revision performed a systematic review. Since GIST is a rare type of tumor, clinical evidence is not sufficient to answer several clinical and background questions. Thus, in these guidelines, we considered that consensus among the experts who manage GIST, the balance between benefits and harms, patients' wishes, medical economic perspective, etc. are important considerations in addition to the evidence. Although guidelines for the treatment of GIST have also been published by the National Comprehensive Cancer Network (NCCN) and the European Society for Medical Oncology (ESMO), there are some differences between the treatments proposed in those guidelines and the treatments in the present guidelines because of the differences in health insurance systems among countries.

Current status of and future prospects for the treatment of unresectable or metastatic gastrointestinal stromal tumours

Gastrointestinal stromal tumours (GISTs) are soft-tissue sarcomas of the gastrointestinal tract. Surgery is the standard treatment for localised disease, but the risk of relapse and progression to more advanced disease is substantial. Following the discovery of the molecular mechanisms underlying GISTs, targeted therapies for advanced GIST were developed, with the first being the tyrosine kinase inhibitor (TKI) imatinib. Imatinib is recommended in international guidelines as first-line therapy to reduce the risk of GIST relapse in high-risk patients, and for locally advanced, inoperable and metastatic disease. Unfortunately, imatinib resistance frequently occurs and, therefore, second-line (sunitinib) and third-line (regorafenib) TKIs have been developed. Treatment options are limited for patients with GIST that has progressed despite these therapies. A number of other TKIs for advanced/metastatic GIST have been approved in some countries. Ripretinib is approved as fourth-line treatment of GIST and avapritinib is approved for GIST harbouring specific genetic mutations, while larotrectinib and entrectinib are approved for solid tumours (including GIST) with specific genetic mutations. In Japan, pimitespib, a heat shock protein 90 (HSP90) inhibitor, is now available as a fourth-line therapy for GIST. Clinical studies of pimitespib have indicated that it has good efficacy and tolerability, importantly not displaying the ocular toxicity of previously developed HSP90 inhibitors. Additional approaches for advanced GIST have been investigated, including alternative uses of currently available TKIs (such as combination therapy), novel TKIs, antibody-drug conjugates, and immunotherapies. Given the poor prognosis of advanced GIST, the development of new therapies remains an important goal.

Benefit of Continuation of Low-Dose Imatinib for Gastrointestinal Stromal Tumors despite Adverse Events with Regular-Dose Imatinib

Tyrosine kinase inhibitors (TKIs) such as imatinib improve the prognosis of patients with gastrointestinal stromal tumors (GISTs). However, treatment options for GISTs are still limited, and the continuation of TKIs is difficult due to adverse events in some cases. The effectiveness of low-dose imatinib is unclear. We report 2 cases to show effectiveness of low-dose imatinib in patients with adverse events. The first case is a male in his early 60s with a history of intestinal GIST resection who was diagnosed with recurrent GIST with peritoneal dissemination. He was started on low-dose imatinib (300 mg) because of a history of subconjunctival hemorrhage after receiving postoperative imatinib. Follow-up contrast-enhanced ultrasonography revealed that the tumors had shrunk in size and number after 2 months of treatment with 300-mg imatinib. He continued this treatment and showed partial response for 8 months. The second case is a female in her late 70s with rectal GIST who was treated with imatinib 400 mg. Due to a severe skin lesion, she changed her treatment to sunitinib 2 months after initiation. However, new metastasis in the liver was confirmed after 4 months of administration of sunitinib. She underwent surgical esection of the rectal tumor to reduce the volume. After the surgery, low-dose imatinib (300 mg) with oral steroids was adopted. Follow-up confirmed the absence of recurrence at the rectum and no increase in hepatic tumor size for 18 months. Aggressive treatment with low-dose imatinib instead of discontinuation or alteration of treatment may benefit patients with unresectable and postoperative GISTs with sensible mutation to imatinib.

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.

Tyrosine kinase inhibitors rechallenge in solid tumors: a review of literature and a case description with lenvatinib in thyroid cancer

INTRODUCTION

In the last decade tyrosine kinase inhibitors (TKIs) have been employed for a wide range of hematological and solid tumors and today they represent a valid therapeutic option for different neoplasms. Among them, both sorafenib and lenvatinib were approved for the treatment of radioactive iodine (RAI) refractory differentiated thyroid carcinoma (DTC). Unfortunately, in some cases the efficacy of TKIs is limited by the onset of drug resistance after the initial response. Areas covered: We report the case of a patient with a RAI refractory advanced DTC, treated with lenvatinib after surgery, multiple RAI administrations, traditional chemotherapy, and sorafenib. During treatment with lenvatinib, a noticeable response was detected by sequential computed tomography scans but, after 27 months, tumor progression became evident and led to lenvatinib interruption. In absence of any active treatment, a further disease progression was documented, and lenvatinib was re-administered obtaining a new objective response. Starting from this case report, we review available reports about the rechallenge with TKIs in solid tumors, discussing the possible mechanisms underlying the efficacy of this approach. Expert commentary: Rechallenge with TKIs in solid tumors could be a therapeutic option in subjects with advanced and metastatic DTC who experience a progressive disease after initial response to lenvatinib.

Hepatectomy for liver metastasis from gastrointestinal stromal tumor in the era of imatinib mesylate: a case series study

The prognosis of metastatic gastrointestinal stromal tumor (GIST) has improved since the introduction of imatinib mesylate; however, acquired resistance has been reported, so alternative treatment option is needed. We evaluated the efficacy of hepatectomy for metastatic GIST. Six patients with liver metastases from GIST underwent hepatectomy. Four were treated with imatinib mesylate before hepatectomy, and all the patients were treated with imatinib mesylate after hepatectomy. Patients were followed-up for a mean duration of 113.5 months after hepatectomy. Complete resection was accomplished in four patients, with incomplete resection performed in the remaining two patients due to peritoneal dissemination. One patient with incomplete resection died 10 months after surgery. One patient with complete resection has survived without disease progression since initial hepatectomy. The remaining four patients with progressive disease during imatinib mesylate treatment developed tumor recurrence and three of them underwent a second hepatectomy. These three patients underwent complete resection during repeat surgery. In total, three patients died during the follow-up period, all of whom had tumors of small intestine origin. Primary tumor site (small intestine vs. others) was identified as a risk factor of mortality (P = 0.02). Although not statistically significant, there was a trend toward better outcomes in patients with exon 11 mutations. Surgical resection for metastatic GIST was shown to be effective and needed to achieve a better prognosis. Repeat hepatectomy demonstrated efficacy in selected patients. Hepatectomy should be considered based on tumor characteristics such as primary tumor site and c-KIT mutation status.

Clinical outcomes of patients with gastrointestinal stromal tumor in phase I clinical trials

BACKGROUND

The prognosis of patients with gastrointestinal stromal tumor (GIST) after the failure of standard therapies is poor with supportive care alone. Guidelines recommend clinical trials, and patients with good performance status following standard therapies are often eligible for phase I clinical trials of investigational agents; however, there are no detailed reports on the clinical outcomes of GIST patients enrolled in these trials.

METHODS

We retrospectively reviewed the clinical outcomes of 21 consecutive GIST patients who were enrolled in one or more phase I clinical trials at a single center between March 2009 and November 2014.

RESULTS

The median age was 57 years, and the median number of previous lines of standard chemotherapy was three. Chemotherapy before enrollment in a phase I clinical trial included imatinib, sunitinib, and regorafenib in 100, 95, and 43 % of patients, respectively. None of the patients achieved objective response. Ten patients (47.6 %) were determined to be stable according to the Response Evaluation Criteria in Solid Tumors; four of them (19.0 %) maintained their status for more than 24 weeks. Four patients achieved partial response according to the Choi criteria. No dose-limiting toxicity was observed; however, severe adverse events and grade 3 or higher toxicities were reported in one (4.8 %) and two patients (9.5 %), respectively. Although no treatment-related deaths occurred, one patient (4.8 %) died within 30 days after the last drug administration because of disease progression. The median progression-free survival was 1.9 months, and the median overall survival time has not been reached.

CONCLUSIONS

Data suggested that phase I clinical trials were feasible and may provide prognostic benefits to GIST patients after standard therapies, indicating that enrollment in these studies may provide a treatment option for these patients.

Asian Consensus Guidelines for the Diagnosis and Management of Gastrointestinal Stromal Tumor

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors originating in the gastrointestinal tract. With the introduction of molecular-targeted therapy for GISTs which has yielded remarkable outcomes, these tumors have become a model of multidisciplinary oncological treatment. Although Western clinical guidelines are available for GISTs, such as those published by the National Comprehensive Cancer Network (NCCN) and the European Society of Medical Oncology (ESMO), the clinical situations in Asian countries are different from those in Western countries in terms of diagnostic methods, surgical approach, and availability of new targeted agents. Accordingly, we have reviewed current versions of several GIST guidelines published by Asian countries (Japan, Korea, China, and Taiwan) and the NCCN and ESMO and discussed the areas of dissensus. We here present the first version of the Asian GIST consensus guidelines that were prepared through a series of meetings involving multidisciplinary experts in the four countries. These guidelines provide an optimal approach to the diagnosis and management of GIST patients in Asian countries.