Long-term follow-up results of the multicenter phase II trial of regorafenib in patients with metastatic and/or unresectable GI stromal tumor after failure of standard tyrosine kinase inhibitor therapy.

BACKGROUND: This investigator-initiated trial provided the justification for the phase III GRID study resulting in worldwide regulatory approval of regorafenib as a third-line therapy for patients with metastatic gastrointestinal stromal tumors (GIST). We report the genotype analyses, long-term safety, and activity results from this initial trial of regorafenib in GIST. PATIENTS AND METHODS: The trial was conducted between February 2010 and January 2014, among adult patients with metastatic GIST, after failure of at least imatinib and sunitinib. Patients received regorafenib orally, 160 mg once daily, days 1-21 of a 28-day cycle. Clinical benefit rate (CBR), defined as complete or partial response (PR), or stable disease lasting ≥16 weeks per RECIST 1.1, progression-free survival (PFS), overall survival (OS), long-term safety data, and metabolic response by functional imaging were assessed. RESULTS: Thirty-three patients received at least one dose of regorafenib. The median follow-up was 41 months. CBR was documented in 25 of 33 patients [76%; 95% confidence interval (CI) 58% to 89%], including six PRs. The median PFS was 13.2 months (95% CI 9.2-18.3 months) including four patients who remained progression-free at study closure, each achieving clinical benefit for more than 3 years (range 36.8-43.5 months). The median OS was 25 months (95% CI 13.2-39.1 months). Patients whose tumors harbored a KIT exon 11 mutation demonstrated the longest median PFS (13.4 months), whereas patients with KIT/PDGFRA wild-type, non-SDH-deficient tumors experienced a median 1.6 months PFS (P < 0.0001). Long-term safety profile is consistent with previous reports; hand-foot skin reaction and hypertension were the most common reasons for dose reduction. Notably, regorafenib induced objective responses and durable benefit in SDH-deficient GIST. CONCLUSIONS: Long-term follow-up of patients with metastatic GIST treated with regorafenib suggests particular benefit among patients with primary KIT exon 11 mutations and those with SDH-deficient GIST. Dose modifications are frequently required to manage treatment-related toxicities. CLINICAL TRIAL NUMBER: NCT01068769.

The Signature Program: Bringing the Protocol to the Patient.

Early-phase clinical development in oncology has evolved dramatically with the deciphering of the human genome in 2004. Genomic analysis and the tools identifying genetically disrupted pathways within a patient's tumor have been a driving force for personalized medicine and for the development of highly targeted novel therapies. Tumors are often genetically heterogeneous, with multiple concurrent genetic abnormalities. On the other hand, tumors arising from different tissues may share identical molecular drivers.

A nonrandom association of gastrointestinal stromal tumor (GIST) and desmoid tumor (deep fibromatosis): case series of 28 patients.

BACKGROUND: Gastrointestinal stromal tumors (GISTs) and desmoid tumors (DTs) are two rare mesenchymal tumor. Anecdotal reports of individuals with both diseases led us to make the hypothesis that the association is a nonrandom event as the probability would be extremely low to observe such cases if they were independent events. PATIENTS AND METHODS: We evaluated the existence of patients with GIST and DT in a large multicenter cohort at 10 institutions in the United States, Australia and Europe. Data on gender, age at diagnosis, KIT, PDGFRA, CTNNB1 mutation status and follow-up time after diagnosis were collected. RESULTS: We identified 28 patients diagnosed with both tumors. DT was diagnosed after GIST in 75% of patients and concomitantly in 21%. In only one case (4%), GIST was diagnosed after DT. KIT or PDGFRA mutations were detected in 12 of 14 GIST, 9 in KIT exon 11, 2 in KIT exon 9 and 1 in PDGFRA. CONCLUSION: A statistical analysis of these 28 cases suggests a nonrandom association between GIST and DT. Further studies may be able to elucidate the underlying biology responsible for this association.

Frequencies of KIT and PDGFRA mutations in the MolecGIST prospective population-based study differ from those of advanced GISTs.

Gastrointestinal stromal tumors (GISTs) are the most common human sarcoma. Most of the data available on GISTs derive from retrospective studies of patients referred to oncology centers. The MolecGIST study sought to determine and correlate clinicopathological and molecular characteristics of GISTs. Tumor samples and clinical records were prospectively obtained and reviewed for patients diagnosed in France during a 24-month period. Five hundred and ninety-six patients were included, of whom 10% had synchronous metastases. GISTs originated from the stomach, small bowel or other site in 56.4, 30.2 and 13.4% of cases, respectively. The main prognostic markers, tumor localization, size and mitotic index were not independent variables (P < 0.0001). Mutational status was determined in 492 (83%) patients, and 138 different mutations were identified. KIT and PDGFRA mutations were detected in 348 (71%) and 74 (15%) patients, respectively, contrasting with 82.8 and 2.1% in patients with advanced GIST (MetaGIST) (P < 0.0001). Further comparison of localized GISTs in the MolecGIST cohort with advanced GISTs from previous clinical trials showed that the mutations of PDGFRA exon18 (D842V and others) as well as KIT exon11 substitutions (W557R and V559D) were more likely to be seen in patients with localized GISTs (odds ratio 7.9, 3.1, 2.7 and 2.5, respectively), while KIT exon 9 502_503dup and KIT exon 11 557_559del were more frequent in metastatic GISTs (odds ratio of 0.3 and 0.5, respectively). These data suggest that KIT and PDGFRA mutations and standardized mitotic count deserve to be investigated to evaluate the relapse risk of GISTs.

Hypoxia-induced inflammatory cytokine secretion in human adipose tissue stromovascular cells.

AIMS: Hypoxia has been implicated as a cause of adipose tissue inflammation in obesity, although the inflammatory response of human adipose tissue to hypoxia is not well understood. The goal of this study was to define in vitro inflammatory responses of human adipose tissue to hypoxia and identify molecular mechanisms of hypoxia-induced inflammation. METHODS: The inflammatory milieu and responses of visceral (VAT) and subcutaneous (SAT) adipose tissue explants and purified stromovascular cells (SVFs) from obese and lean humans were studied in an in vitro hypoxic culture system using quantitative real-time PCR, ELISA, western blotting, immunofluorescence microscopy, flow cytometry and immunohistochemistry. RESULTS: Human adipose tissue in obesity demonstrates an increased leucocyte infiltrate that is greater in VAT than SAT and involves macrophages, T cells and natural killer (NK) cells. Hypoxic culture regulates inflammatory cytokine secretion and transcription of metabolic stress response genes in human adipose tissue SVF. Adipocyte diameter is increased and adipose tissue capillary density is decreased in obese participants. Inhibition of c-Jun terminal kinase (JNK) or p38 significantly attenuates hypoxia-induced SVF inflammatory responses. Hypoxia induces phosphorylation of p38 in adipose tissue. CONCLUSIONS: Human adipose tissue in obesity is characterised by a depot-specific inflammatory cell infiltrate that involves not only macrophages, but also T cells and NK cells. Hypoxia induces inflammatory cytokine secretion by human adipose tissue SVF, the primary source of which is adipose tissue macrophages. These data implicate p38 in the regulation of hypoxia-induced inflammation and suggest that alterations in adipocyte diameter and adipose tissue capillary density may be potential underlying causes of adipose tissue hypoxia.

Neurofibromatosis type 1-associated wild-type gastrointestinal stromal tumor treated with anti-IGF-1R monoclonal antibody.

Gastrointestinal stromal tumors lacking mutations in KIT or PDGFRα are known as wild type (WT) and are less responsive to imatinib. These WT tumors are hypothesized to be dependent on signaling through the insulin-like growth factor 1 receptor (IGF-1R). We report the case of a 29-year-old woman with neurofibromatosis type 1-associated WT GIST treated with an anti-IGF-1R monoclonal antibody. Treatment was ineffective, and the potential basis for lack of response is discussed in the context of IGF-1R expression levels measured within this patients' primary tumor. We suggest that future clinical trials of anti-IGF-1R therapies prospectively determine tumor IGF-1R expression levels for correlation with response to treatment.

Heterogeneity of kinase inhibitor resistance mechanisms in GIST.

Most GIST patients develop clinical resistance to KIT/PDGFRA tyrosine kinase inhibitors (TKI). However, it is unclear whether clinical resistance results from single or multiple molecular mechanisms in each patient. KIT and PDGFRA mutations were evaluated in 53 GIST metastases obtained from 14 patients who underwent surgical debulking after progression on imatinib or sunitinib. To interrogate possible resistance mechanisms across a broad biological spectrum of GISTs, inter- and intra-lesional heterogeneity of molecular drug-resistance mechanisms were evaluated in the following: conventional KIT (CD117)-positive GISTs with KIT mutations in exon 9, 11 or 13; KIT-negative GISTs; GISTs with unusual morphology; and KIT/PDGFRA wild-type GISTs. Genomic KIT and PDGFRA mutations were characterized systematically, using complementary techniques including D-HPLC for KIT exons 9, 11-18 and PDGFRA exons 12, 14, 18, and mutation-specific PCR (V654A, D820G, N822K, Y823D). Primary KIT oncogenic mutations were found in 11/14 patients (79%). Of these, 9/11 (83%), had secondary drug-resistant KIT mutations, including six (67%) with two to five different secondary mutations in separate metastases, and three (34%) with two secondary KIT mutations in the same metastasis. The secondary mutations clustered in the KIT ATP binding pocket and kinase catalytic regions. FISH analyses revealed KIT amplicons in 2/10 metastases lacking secondary KIT mutations. This study demonstrates extensive intra- and inter-lesional heterogeneity of resistance mutations and gene amplification in patients with clinically progressing GIST. KIT kinase resistance mutations were not found in KIT/PDGFRA wild-type GISTs or in KIT-mutant GISTs showing unusual morphology and/or loss of KIT expression by IHC, indicating that resistance mechanisms are fundamentally different in these tumours. Our observations underscore the heterogeneity of clinical TKI resistance, and highlight the therapeutic challenges involved in salvaging patients after clinical progression on TKI monotherapies.

MicroRNA expression signature of human sarcomas.

MicroRNAs (miRNAs) are approximately 22 nucleotide-long noncoding RNAs involved in several biological processes including development, differentiation and proliferation. Recent studies suggest that knowledge of miRNA expression patterns in cancer may have substantial value for diagnostic and prognostic determinations as well as for eventual therapeutic intervention. We performed comprehensive analysis of miRNA expression profiles of 27 sarcomas, 5 normal smooth muscle and 2 normal skeletal muscle tissues using microarray technology and/or small RNA cloning approaches. The miRNA expression profiles are distinct among the tumor types as demonstrated by an unsupervised hierarchical clustering, and unique miRNA expression signatures were identified in each tumor class. Remarkably, the miRNA expression patterns suggested that two of the sarcomas had been misdiagnosed and this was confirmed by reevaluation of the tumors using histopathologic and molecular analyses. Using the cloning approach, we also identified 31 novel miRNAs or other small RNA effectors in the sarcomas and normal skeletal muscle tissues examined. Our data show that different histological types of sarcoma have distinct miRNA expression patterns, reflecting the apparent lineage and differentiation status of the tumors. The identification of unique miRNA signatures in each tumor type may indicate their role in tumorigenesis and may aid in diagnosis of soft tissue sarcomas.

Serum leptin levels, hepatic leptin receptor transcription, and clinical predictors of non-alcoholic steatohepatitis in obese bariatric surgery patients.

BACKGROUND: Non-alcoholic steatohepatitis (NASH) is a major cause of liver disease in morbidly obese patients. Clinical predictors of NASH remain elusive, as do molecular mechanisms of pathogenesis. METHODS: A series of 35 morbidly obese patients undergoing bariatric surgery had a liver biopsy performed for standard histologic analysis. In addition, RNA was obtained from liver tissue and analyzed for leptin receptor gene expression. Regression analysis was used to correlate clinical variables, including serum leptin levels and hepatic leptin receptor gene expression, with the presence of histologically confirmed NASH. RESULTS: Of the 35 subjects enrolled, 29% had steatosis only, 60% had NASH, and 11% had normal liver histology. Among the clinical variables studied, only diabetes mellitus was an independent predictor of NASH. There was a trend toward lower levels of mRNA encoding the long form of the leptin receptor in hepatic tissue from patients with NASH compared to those with steatosis only. CONCLUSIONS: Diabetes mellitus is associated with an increased risk of NASH in obese patients. Downregulation of hepatic leptin receptor may play a role in the pathogenesis of NASH.

Endoluminal treatment of ruptured abdominal aortic aneurysm with small intestinal submucosa sandwich endografts: a pilot study in sheep.

PURPOSE: To evaluate efficacy of small intestinal submucosa (SIS) Sandwich endografts for the treatment of acute rupture of abdominal aortic aneurysms (AAA) and to explore the short-term reaction of the aorta to this material. METHODS: In eight adult sheep, an infrarenal AAA was created transluminally by dilation of a short Palmaz stent. In six sheep, the aneurysm was then ruptured by overdilation of the stent with a large angioplasty balloon. Two sheep with AAAs that were not ruptured served as controls. A SIS Sandwich endograft, consisting of a Z stent frame with 5 bodies and covered inside and out with SIS, was used to exclude the ruptured and non-ruptured AAAs. Follow-up aortography was done immediately after the procedure and before sacrifice at 4, 8, or 12 weeks. Autopsy and histologic studies followed. RESULTS: Endograft placement was successful in all eight sheep. Both ruptured and non-ruptured AAAs were successfully excluded. Three animals with AAA rupture developed hind leg paralysis due to compromise of the arterial supply to the lower spinal cord and were sacrificed 1 day after the procedure. In five animals, three with rupture and two controls, follow-up aortograms revealed no aortic stenoses and no perigraft leaks. Gross and histologic studies revealed incorporation of the endografts into the aortic wall with replacement of SIS by dense neointima that was completely endothelialized in areas where the endograft was in direct contact with the aortic wall. In central portions of the endograft, in contact with the thrombosed aneurysm, endothelialization was incomplete even at 12 weeks. CONCLUSION: The SIS Sandwich endografts effectively excluded simple AAAs and ruptured AAAs. They were rapidly incorporated into the aortic wall. A detailed long-term study is warranted.

Late mortality after orthotopic liver transplantation.

BACKGROUND: Mortality within the first year after orthotopic liver transplantation (OLTx) is usually due to infection or allograft failure. Late complications leading to death after OLTx have not been extensively evaluated. The aim of this study was to determine the incidence of late mortality and to identify the most common causes and risk factors associated with late mortality after OLTx. METHODS: A total of 479 OLTx were performed in 459 patients (320 males, 139 females; mean age 47 years, range 13 to 69) between September 1991 and April 2000. All patient deaths among liver transplant recipients who survived more than 1 year after transplantation (follow-up mean 3.4 years, median 3, range 1 to 8.6) were reviewed. RESULTS: In all, 122 allografts (24%) were lost in 109 patients during the study period (24%). Seventy-five allografts were lost in 69 patients by 1 year (15%). Forty-seven allografts were lost in 40 patients who survived at least 1 year (9.6%). Actuarial survivals at 2 years, 5 years, and 9 years were 95%, 85%, and 80%, respectively (based on 100% survival at 1 year). The causes of the late mortality were malignancy (9 patients), disease recurrence (8), late infection (6), renal failure complications (5), cardiovascular complications (4), chronic rejection (3), gastrointestinal hemorrhage (2), medication noncompliance (1), and unknown (2). CONCLUSIONS: Malignancy and disease recurrence are the major causes of late mortality among adult OLTx recipients. Pharmacologic immunosuppression is associated with many of the causes of late mortality. Advances in immunosuppression with less toxicity may improve long-term survival after OLTx.

Pathological documentation of complete elimination of Barrett's metaplasia following endoscopic multipolar electrocoagulation therapy.

The previous paradigm that Barrett's is an irreversible premalignant lesion has recently been challenged by a proliferation of reports documenting elimination of Barrett's by a variety of endoscopic techniques. Whether Barrett's is entirely eliminated is unknown as endoscopic biopsy samples the surface of the epithelium only. Numerous reports document underlying specialised columnar epithelium in many of these trials. Until now there have been no reports of pathological examination of the entire oesophagus as a specimen. This case documents complete elimination of intestinal metaplasia from the oesophagus and supports the biological plausibility of these research techniques.

Treatment of progressive hepatitis C recurrence after liver transplantation with combination interferon plus ribavirin.

Hepatitis C virus (HCV) recurrence after orthotopic liver transplantation (OLT) is common, although the majority of cases are mild. A subset of transplant recipients develops progressive allograft injury, including cirrhosis and allograft failure. Minimal data are available on the safety and efficacy of antiviral treatment in this group of patients. The aim of this study is to review our experience in the treatment of moderate to severe HCV recurrence with combination interferon-alpha2b and ribavirin (IFN/RIB). Between October 1993 and October 1999, a total of 197 patients underwent OLT for HCV-related liver failure. This study describes 12 transplant recipients with moderate to severe recurrence treated with IFN/RIB. All patients met at least 1 of the following inclusion criteria: (1) moderate to severe inflammation (grade III to IV) on allograft biopsy, (2) bridging fibrosis on allograft biopsy, or (3) severe cholestasis attributable solely to HCV recurrence. Two patients had undergone re-OLT for allograft cirrhosis secondary to HCV recurrence and now had evidence of progressive HCV in their second allografts. Appropriate dose reductions of both IFN and RIB, as well as initiation of granulocyte colony-stimulating factor (G-CSF), for marked leukopenia were recorded. IFN/RIB therapy was started 60 to 647 days post-OLT, and duration of therapy ranged from 39 to 515 days. Seven patients were administered G-CSF to successfully treat leukopenia. Six of the 12 patients (50%) became HCV RNA negative by polymerase chain reaction. One of these 6 patients (no. 1) was HCV RNA negative at 6 months but chose to discontinue therapy because of intolerable side effects, experienced a relapse, and was HCV RNA positive at 12 months. Two of the remaining 5 patients were HCV RNA negative at 2 and 9 months off therapy. For the entire group, there was a statistically significant decrease in serum biochemical indices assessed at initiation of therapy and 1, 3, and 6 months into therapy. Most patients required dose reductions of both IFN and RIB. Five patients died; 3 patients died of liver-related complications that included severe intrahepatic biliary cholestasis, severe HCV recurrence, and chronic rejection with profound cholestasis. In the subset of HCV-positive liver transplant recipients with moderate to severe recurrence, combination IFN/RIB therapy resulted in complete virological response (serum RNA negative) in 6 of 12 patients ( approximately 50%). However, only 1 of 12 patients (8.3%) had sustained virological clearance after cessation of IFN/RIB therapy. Dose reductions of both IFN and RIB were required in most patients. The use of G-CSF (sometimes preemptively) allowed correction of leukopenia and full-dose antiviral therapy. Multicenter trials using combination therapy to identify factors predictive of response are needed in the subset of patients with progressive allograft injury.

Small intestinal submucosa covered expandable Z stents for treatment of tracheal injury: an experimental pilot study in swine.

PURPOSE: To evaluate efficacy of small intestinal submucosa (SIS) as a stent covering in healing experimentally created tracheal defects and to explore the trachea's reaction to placement of SIS-covered stents. MATERIAL AND METHODS: A tracheal defect with a diameter of approximately 10 mm was created in six swine with use of a blade or electrocauterization. A double-body, self-expandable SIS-covered Gianturco Rösch Z stent was placed into the trachea to cover the defect. The animals were observed, and were killed when they developed respiratory problems. Autopsy and histologic studies were performed. RESULTS: The SIS-covered stents were accurately placed without immediate complications related to placement. All animals developed respiratory problems on follow-up. One animal died 9 days after procedure because of pneumonia, the others five were killed at 12, 17, 18, 28, and 56 days because of stridor, wheezing, and cough. At autopsy and histology, the tracheal defects were found to be completely healed, with epithelial lining and regeneration of submucosal glands. Animals whose defects were created with a blade demonstrated cartilage remodeling between 9 and 18 days, and apparent deposition of new cartilage at 28 days after SIS placement. The defects made by electrocauterization showed only fibrous tissue with no cartilage regeneration. The tracheal lumen was narrowed by overgrowth of granulation tissue, particularly at the end wires of the stents. In three animals, polypoid masses caused 60%, 70%, and 80% tracheal obstruction, respectively. CONCLUSION: Placement of SIS-covered stents contributed to rapid and effective healing of large tracheal defects. Rigidity and oversizing of Gianturco Rösch Z stents led to secondary changes of the tracheal wall, causing significant airway obstructions. Smaller size and flexible stents should be selected for future work.

The square stent-based large vessel occluder: an experimental pilot study.

PURPOSE: The purpose of this study is in vitro and in vivo experimental evaluation of a square stent-based vascular occlusion device for large vessels. MATERIALS AND METHODS: Square stent-based large vessel occluders (LVO) 5 mm-50 mm in size were constructed from stainless-steel square stents covered by porcine small intestine submucosa (SIS). The LVOs with two back-side barbs were delivered through a guiding catheter. The LVOs with two back-side barbs and two frontal barbs were front-loaded and delivered coaxially. A pusher with a retention mechanism at its end was used for deployment. In vitro testing for competency was performed with use of a flow model with pressure increases. In an experimental pilot study in seven pigs and five dogs, 16 LVOs were placed into the aorta (n = 4), common iliac artery (n = 2), pulmonary artery (n = 4), and medial sacral artery (n = 6). Four animals received two LVOs in different locations. Angiography was performed before and after placement of each LVO. Animals were followed for as long as 3 months with use of angiography and were then killed for gross and histologic evaluation. RESULTS: In vitro LVOs with two and four barbs were easily collapsed and pushed through or front-loaded into guiding catheters (6-F for a 5-mm occluder, 10-F for a 50-mm occluder). A 20-mm LVO adapted to tubular structures 10-15 mm in diameter, forming polygons 17-18.5 mm in length. In the flow model, LVOs endured pressure increases to 300 mm Hg. In vivo, the LVOs self-expanded and adapted to the vessel without migration in all cases. The locking pusher allowed precise LVO placement and engagement of its barbs into the vessel wall before complete deployment, preventing dislodgment by blood flow. Complete arterial occlusion occurred within 10-20 minutes and arteries remained occluded until the animal was killed in all cases. After 2 months, histologic evaluation revealed replacement of SIS by host tissue and its remodeling with variable fibrocytes, fibroblasts, and some inflammatory cells. Complete endothelialization was seen on both sides of the LVO. CONCLUSION: The SIS LVO is effective and reliable for acute and chronic occlusion in a high flow model in an experimental animal.