KIT and PDGFRA Mutations and Survival of Gastrointestinal Stromal Tumor Patients Treated with Adjuvant Imatinib in a Randomized Trial.

PURPOSE: Limited data are available about the influence of KIT and PDGFRA mutations on overall survival (OS) of patients with gastrointestinal stromal tumor (GIST) treated with adjuvant imatinib. PATIENTS AND METHODS: The Scandinavian Sarcoma Group XVIII/AIO multicenter trial accrued 400 patients with a high risk for GIST recurrence after macroscopically complete surgery between February 4, 2004, and September 29, 2008. The patients received adjuvant imatinib 400 mg/day for either 1 year or 3 years based on random allocation. We analyzed using conventional sequencing KIT and PDGFRA mutations centrally from 341 (85%) patients who had localized, centrally confirmed GIST, and correlated the results with recurrence-free survival (RFS) and OS in exploratory analyses. RESULTS: During a median follow-up time of 10 years, 164 RFS events and 76 deaths occurred. Most patients were re-treated with imatinib when GIST recurred. Patients with KIT exon 11 deletion or indel mutation treated with 3 years of adjuvant imatinib survived longer than patients treated for 1 year [10-year OS 86% versus 64%, respectively; HR, 0.34; 95% confidence interval (CI), 0.15-0.72; P = 0.007], and also had longer RFS (10-year RFS 47% versus 29%; HR, 0.48; 95% CI, 0.31-0.74; P < 0.001). Patients with KIT exon 9 mutation had unfavorable OS regardless of the duration of adjuvant imatinib. CONCLUSIONS: Compared with 1 year of imatinib, 3 years of adjuvant imatinib led to 66% reduction in the estimated risk of death and a high 10-year OS rate in the subset of patients with a KIT exon 11 deletion/indel mutation.

Survival Outcomes Associated With 3 Years vs 1 Year of Adjuvant Imatinib for Patients With High-Risk Gastrointestinal Stromal Tumors: An Analysis of a Randomized Clinical Trial After 10-Year Follow-up.

Importance: Adjuvant imatinib is associated with improved recurrence-free survival (RFS) when administered after surgery to patients with operable gastrointestinal stromal tumor (GIST), but its influence on overall survival (OS) has remained uncertain. Objective: To evaluate the effect of adjuvant imatinib on OS of patients who have a high estimated risk for GIST recurrence after macroscopically complete surgery. Design, Setting, and Participants: In this open-label, randomized (1:1), multicenter phase 3 clinical trial conducted in Finland, Germany, Norway, and Sweden, 400 patients who had undergone macroscopically complete surgery for GIST with a high estimated risk for recurrence according to the modified National Institutes of Health Consensus Criteria were enrolled between February 2004 and September 2008. Data for this follow-up analysis were analyzed from September to November, 2019. Interventions: Imatinib 400 mg/d administered orally for either 12 months or 36 months after surgery. Main Outcomes And Measures: The primary end point was RFS; the secondary objectives included OS and treatment safety. Results: The intention-to-treat cohort consisted of 397 patients (12-month group, 199; 36-month group, 198; 201 men and 196 women; median [IQR] age, 62 (51-69) years and 60 (51-67) years, during a median follow-up time of 119 months after the date of randomization, 194 RFS events and 96 OS events were recorded in the intention-to-treat population. Five-year and 10-year RFS was 71.4% and 52.5%, respectively, in the 36-month group and 53.0% and 41.8% in the 12-month group (hazard ratio [HR], 0.66; 95% CI, 0.49-0.87; P = .003). In the 36-month group, 5-year OS and 10-year OS rates were 92.0% and 79.0%, respectively, and in the 12-month group 85.5% and 65.3% (HR, 0.55; 95% CI, 0.37-0.83; P = .004). The results were similar in the efficacy population, from which 15 patients who did not have GIST in central pathology review and 24 patients who had intra-abdominal metastases removed at surgery were excluded (36-month group, 10-year OS 81.6%; 12-month group, 66.8%; HR, 0.50; 95% CI, 0.32-0.80; P = .003). No new safety signals were detected. Conclusions and Relevance: Three years of adjuvant imatinib is superior in efficacy compared with 1 year of imatinib. Approximately 50% of deaths may be avoided during the first 10 years of follow-up after surgery with longer adjuvant imatinib treatment. Trial Registration: ClinicalTrials.gov Identifier: NCT00116935.

Six versus eight doses of rituximab in patients with aggressive B cell lymphoma receiving six cycles of CHOP: results from the "Positron Emission Tomography-Guided Therapy of Aggressive Non-Hodgkin Lymphomas" (PETAL) trial.

Standard first-line treatment of aggressive B cell lymphoma comprises six or eight cycles of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) plus eight doses of rituximab (R). Whether adding two doses of rituximab to six cycles of R-CHOP is of therapeutic benefit has not been systematically investigated. The Positron Emission Tomography-Guided Therapy of Aggressive Non-Hodgkin Lymphomas (PETAL) trial investigated the ability of [18F]-fluorodesoxyglucose PET scanning to guide treatment in aggressive non-Hodgkin lymphomas. Patients with B cell lymphomas and a negative interim scan received six cycles of R-CHOP with or without two extra doses of rituximab. For reasons related to trial design, only about a third underwent randomization between the two options. Combining randomized and non-randomized patients enabled subgroup analyses for diffuse large B cell lymphoma (DLBCL; n = 544), primary mediastinal B cell lymphoma (PMBCL; n = 37), and follicular lymphoma (FL) grade 3 (n = 35). With a median follow-up of 52 months, increasing the number of rituximab administrations failed to improve outcome. A non-significant trend for improved event-free survival was seen in DLBCL high-risk patients, as defined by the International Prognostic Index, while inferior survival was observed in female patients below the age of 60 years. Long-term outcome in PMBCL was excellent. Differences between FL grade 3a and FL grade 3b were not apparent. The results were confirmed in a Cox proportional hazard regression model and a propensity score matching analysis. In conclusion, adding two doses of rituximab to six cycles of R-CHOP did not improve outcome in patients with aggressive B cell lymphomas and a fast metabolic treatment response.

Vorinostat in refractory soft tissue sarcomas - Results of a multi-centre phase II trial of the German Soft Tissue Sarcoma and Bone Tumour Working Group (AIO).

INTRODUCTION: New treatment options for patients with metastatic Soft Tissue Sarcoma are urgently needed. Preclinical studies suggested activity of vorinostat, a histone deacetylase inhibitor. METHODS: A multi-centre, open-label, non-randomised phase II trial to investigate the efficacy and safety of vorinostat in patients with locally advanced or metastatic Soft Tissue Sarcoma failing 1st-line anthracycline-based chemotherapy was initiated. Patients were treated with vorinostat 400 mg po qd for 28 d followed by a treatment-free period of 7 d, representing a treatment cycle of 5 weeks. Restaging was performed every three cycles or at clinical progression. RESULTS: Between 06/10 and 09/13, 40 Soft Tissue Sarcoma patients were treated with vorinostat at seven participating centres. Patients had received 1 (n=8, 20%), 2 (n=10, 25%) or ≥3 (n=22, 55%) previous lines of chemotherapy. Best response after three cycles of treatment was stable disease (n=9, 23%). Median progression-free survival and overall survival were 3.2 and 12.3 months, respectively. Six patients showed long-lasting disease stabilisation for up to ten cycles. Statistical analyses failed to identify baseline predictive markers in this subgroup. Major toxicities (grade ≥III) included haematological toxicity (n=6, 15%) gastrointestinal disorders (n=5, 13%), fatigue (n=4, 10%), musculoskeletal pain (n=4, 10%), and pneumonia (n=2, 5%). CONCLUSION: In a heavily pre-treated patient population, objective response to vorinostat was low. However, a small subgroup of patients had long-lasting disease stabilisation. Further studies aiming to identify predictive markers for treatment response as well as exploration of combination regimens are warranted. TRIAL REGISTRATION: NCT00918489 (ClinicalTrials.gov) EudraCT-number: 2008-008513-19.

Needle biopsy through the abdominal wall for the diagnosis of gastrointestinal stromal tumour - Does it increase the risk for tumour cell seeding and recurrence?

PURPOSE: Preoperative percutaneous transabdominal wall biopsy may be considered to diagnose gastrointestinal stromal tumour (GIST) and plan preoperative treatment with tyrosine kinase inhibitors when an endoscopic biopsy is not possible. Hypothetically, a transabdominal wall biopsy might lead to cell seeding and conversion of a local GIST to a disseminated one. We investigated the influence of preoperative needle biopsy on survival outcomes. METHODS: We collected the clinical data from hospital case records of the 397 patients who participated in the Scandinavian Sarcoma Group (SSG) XVIII/Arbeitsgemeinschaft Internistische Onkologie (AIO) randomised trial and who had a transabdominal fine needle and/or core needle biopsy carried out prior to study entry. The SSG XVIII/AIO trial compared 1 and 3 years of adjuvant imatinib in a patient population with a high risk of GIST recurrence after macroscopically radical surgery. The primary end-point was recurrence-free survival (RFS), and the secondary end-points included overall survival (OS). RESULTS: A total of 47 (12.0%) out of the 393 patients with data available underwent a percutaneous biopsy. No significant difference in RFS or OS was found between the patients who underwent or did not undergo a percutaneous biopsy either in the entire series or in subpopulation analyses, except for a statistically significant RFS advantage for patients who had a percutaneous biopsy and a tumour ≥10 cm in diameter. CONCLUSION: A preoperative diagnostic percutaneous biopsy of a suspected GIST may not increase the risk for GIST recurrence in a patient population who receive adjuvant imatinib after the biopsy.

Radioembolization in patients with progressive gastrointestinal stromal tumor liver metastases undergoing treatment with tyrosine kinase inhibitors.

PURPOSE: Gastrointestinal stromal tumors (GISTs) spread frequently to the peritoneum and the liver. If metastasectomy or tyrosine kinase inhibitors (TKIs) fail, interventional ablation techniques are considered. The purpose of this study is to assess the progression-free interval (PFI) of GIST liver metastases after radioembolization (RE). MATERIALS AND METHODS: Eleven patients with progressive GIST liver metastases undergoing TKI therapy were referred for RE; one was excluded because of a large hepatopulmonary shunt, and one was lost to follow-up. Depending on intrahepatic tumor distribution, one or both liver lobes were treated with RE. Contrast-enhanced magnetic resonance imaging, contrast-enhanced computed tomography (CT), and [(18)F]fluorodeoxyglucose positron-emission tomography/CT were used for follow-up. RESULTS: In all, 16 liver lobes were treated with a mean activity of 1.06 GBq ± 0.37 (range, 0.55-1.88) per lobe. Three patients showed complete response, five showed partial response, and one showed stable disease. No patient showed progressive disease after RE. Median PFI was 15.9 months (range, 4-29 mo). Median survival was 29.8 months (range, 10-72 mo). No radiation-induced liver disease developed; however, one patient required surgery for persistent stomach ulcer. CONCLUSIONS: RE offers a safe and effective treatment for patients with GIST liver metastases who do not show a response to TKIs. RE could be an option for earlier phases of therapy in patients with mutational status. The results might also challenge the notion that GISTs are resistant to radiation therapy.

Risk factors for gastrointestinal stromal tumor recurrence in patients treated with adjuvant imatinib.

BACKGROUND: Little is known about the factors that predict for gastrointestinal stromal tumor (GIST) recurrence in patients treated with adjuvant imatinib. METHODS: Risk factors for GIST recurrence were identified, and 2 risk stratification scores were developed using the database of the Scandinavian Sarcoma Group (SSG) XVIII trial, where 358 patients with high-risk GIST with no overt metastases were randomly assigned to adjuvant imatinib 400 mg/day either for 12 or 36 months after surgery. The findings were validated in the imatinib arm of the American College of Surgeons Oncology Group Z9001 trial, where 359 patients with GIST were randomized to receive imatinib and 354 were to receive placebo for 12 months. RESULTS: Five factors (high tumor mitotic count, nongastric location, large size, rupture, and adjuvant imatinib for 12 months) were independently associated with unfavorable recurrence-free survival (RFS) in a multivariable analysis in the SSGXVIII cohort. A risk score based on these 5 factors had a concordance index with GIST recurrence of 78.9%. When a simpler score consisting of the 2 strongest predictive factors (mitotic count and tumor site) was devised, the groups with the lowest, intermediate high, and the highest risk had 5-year RFS of 76.7%, 47.5%, and 8.4%, respectively. Both scores were strongly associated with RFS in the validation cohort (P < .001 for each comparison). CONCLUSIONS: The scores generated were effective in stratifying the risk of GIST recurrence in patient populations treated with adjuvant imatinib. Patients with nongastric GIST with a high mitotic count are at a particularly high risk for recurrence.

A phase II trial to assess efficacy and safety of afatinib in extensively pretreated patients with HER2-negative metastatic breast cancer.

Afatinib (BIBW 2992) is an ErbB-family blocker that irreversibly inhibits signaling from all relevant ErbB-family dimers. Afatinib has demonstrated preclinical activity in human epidermal growth factor receptor HER2 (ErbB2)-positive and triple-negative xenograft models of breast cancer, and clinical activity in phase I studies. This was a multicenter phase II study enrolling patients with HER2-negative metastatic breast cancer progressing following no more than three lines of chemotherapy. No prior epidermal growth factor receptor-targeted therapy was allowed. Patients received 50-mg afatinib once daily until disease progression. Tumor assessment was performed at every other 28-day treatment course. The primary endpoint was clinical benefit (CB) for ≥4 treatment courses in triple-negative (Cohort A) metastatic breast cancer (TNBC) and objective responses measured by Response Evaluation Criteria in Solid Tumors in patients with HER2-negative, estrogen receptor-positive, and/or progesterone receptor-positive breast cancer (Cohort B). Fifty patients received treatment, including 29 patients in Cohort A and 21 patients in Cohort B. No objective responses were observed in either cohort. Median progression-free survival was 7.4 and 7.7 weeks in Cohorts A and B, respectively. Three patients with TNBC had stable disease for ≥4 treatment courses, one of them for 12 courses (median 26.3 weeks; range 18.9-47.9 weeks). The most frequently observed afatinib-associated adverse events (AEs) were gastrointestinal and skin-related side effects, which were manageable by symptomatic treatment and dose reductions. Afatinib pharmacokinetics were comparable to those observed in previously reported phase I trials. In conclusion, afatinib had limited activity in HER2-negative breast cancer. AEs were generally manageable and mainly affected the skin and the gastrointestinal tract.

One vs three years of adjuvant imatinib for operable gastrointestinal stromal tumor: a randomized trial.

CONTEXT: Adjuvant imatinib administered for 12 months after surgery has improved recurrence-free survival (RFS) of patients with operable gastrointestinal stromal tumor (GIST) compared with placebo. OBJECTIVE: To investigate the role of imatinib administration duration as adjuvant treatment of patients who have a high estimated risk for GIST recurrence after surgery. DESIGN, SETTING, AND PATIENTS: Patients with KIT-positive GIST removed at surgery were entered between February 2004 and September 2008 to this randomized, open-label phase 3 study conducted in 24 hospitals in Finland, Germany, Norway, and Sweden. The risk of GIST recurrence was estimated using the modified National Institutes of Health Consensus Criteria. INTERVENTION: Imatinib, 400 mg per day, orally for either 12 months or 36 months, started within 12 weeks of surgery. MAIN OUTCOME MEASURES: The primary end point was RFS; the secondary end points included overall survival and treatment safety. RESULTS: Two hundred patients were allocated to each group. The median follow-up time after randomization was 54 months in December 2010. Diagnosis of GIST was confirmed in 382 of 397 patients (96%) in the intention-to-treat population at a central pathology review. KIT or PDGFRA mutation was detected in 333 of 366 tumors (91%) available for testing. Patients assigned for 36 months of imatinib had longer RFS compared with those assigned for 12 months (hazard ratio [HR], 0.46; 95% CI, 0.32-0.65; P < .001; 5-year RFS, 65.6% vs 47.9%, respectively) and longer overall survival (HR, 0.45; 95% CI, 0.22-0.89; P = .02; 5-year survival, 92.0% vs 81.7%). Imatinib was generally well tolerated, but 12.6% and 25.8% of patients assigned to the 12- and 36-month groups, respectively, discontinued imatinib for a reason other than GIST recurrence. CONCLUSION: Compared with 12 months of adjuvant imatinib, 36 months of imatinib improved RFS and overall survival of GIST patients with a high risk of GIST recurrence. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00116935.

Resection of residual disease in patients with metastatic gastrointestinal stromal tumors responding to treatment with imatinib.

Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors of the gastrointestinal tract. Long-term survival of patients with metastatic disease has only been observed in patients with completely resected disease. Recently, the tyrosine kinase inhibitor imatinib has been found to yield responses in the majority of patients with metastatic GIST suggesting improved resectability in responding patients. Combined treatment approaches including resective surgery after imatinib treatment in patients with advanced metastatic disease have rarely been explored. We report a series of 90 patients with metastatic GIST in whom treatment with imatinib enabled 12 patients with mostly recurrent and extensive disease to be considered for resection of residual disease. In 11 of these patients, complete resection could be achieved. Viable tumor cells were found in all but one resected specimens suggesting that despite favorable radiological or clinical responses, imatinib is unlikely to induce pathological complete responses. Until more mature data from prospective trials are available, these data suggest that an early aggressive surgical approach should be considered for all patients with metastatic GIST. Further trials investigating a combined surgical and pre/postoperative treatment with imatinib in patients with advanced metastatic GIST are warranted.

Response to imatinib mesylate of a gastrointestinal stromal tumor with very low expression of KIT.

More than 90% of gastrointestinal stromal tumors (GISTs) express the receptor tyrosine kinase KIT, and activating mutations of the KIT gene are detectable in the vast majority of these tumors. Imatinib mesylate (formerly STI571) is a potent inhibitor of KIT kinase activity and has been proven to be highly active in patients with unresectable or metastatic GIST expressing immunohistochemically detectable KIT protein. Here we report a patient with metastatic GIST who responded well to imatinib mesylate treatment despite the near absence of KIT expression in two different samples of his tumor. The tumor was morphologically typical for a GIST, stained positively for CD34, and harbored an in-frame deletion (WK 557-558) in KIT exon 11 that is common in GISTs. Our experience with this patient suggests that even GISTs with very low levels of KIT expression may respond to imatinib mesylate therapy.

Imatinib mesylate therapy in patients with gastrointestinal stromal tumors and impaired liver function.

Hepatic and peritoneal metastases are the most frequent metastatic lesions in patients with gastrointestinal stromal tumors (GIST), and may result in intra- or extrahepatic cholestasis and altered drug metabolism. While the tyrosine kinase inhibitor imatinib, which has been recently shown to represent the treatment of choice for GIST, is primarily metabolized by the liver, data on the pharmacokinetics and the tolerability of imatinib in patients with increased cholestasis parameters are not yet available. We here report on two patients who received imatinib in the presence of increased bilirubin and/or cholestasis parameters. With a follow-up duration of 3-4 months, we observed no toxicities outside of well-known side effects including some degree of myelosuppression and fluid retention. This report may aid in the decision of imatinib being given under close surveillance to this kind of patients.