Min Hee Ryu

Nivolumab in patients with advanced gastric or gastro-oesophageal junction cancer refractory to, or intolerant of, at least two previous chemotherapy regimens (ONO-4538-12, ATTRACTION-2): a randomised, double-blind, placebo-controlled, phase 3 trial

BACKGROUND Patients with advanced gastric or gastro-oesophageal junction cancer refractory to, or intolerant of, two or more previous regimens of chemotherapy have a poor prognosis, and current guidelines do not recommend any specific treatments for these patients. We assessed the efficacy and safety of nivolumab, a fully human IgG4 monoclonal antibody inhibitor of programmed death-1 (PD-1), in patients with advanced gastric or gastro-oesophageal junction cancer who had been previously been treated with two or more chemotherapy regimens. METHODS In this randomised, double-blind, placebo-controlled, phase 3 trial done at 49 clinical sites in Japan, South Korea, and Taiwan, eligible patients (aged ≥20 years with unresectable advanced or recurrent gastric or gastro-oesophageal junction cancer refractory to, or intolerant of, standard therapy [including two or more previous chemotherapy regimens], with an Eastern Cooperative Oncology Group [ECOG] performance status of 0-1, and naive to anti-PD-1 therapy or other therapeutic antibodies and pharmacotherapies for the regulation of T cells) were recruited. Patients were randomly assigned (2:1) using an interactive web response system to receive 3 mg/kg nivolumab or placebo intravenously every 2 weeks, stratified by country, ECOG performance status, and number of organs with metastases. Study treatment was continued until progressive disease per investigator assessment or onset of toxicities requiring permanent discontinuation. Patients and investigators were masked to group assignment. The primary endpoint was overall survival in the intention-to-treat population. Safety was analysed in all patients who received at least one dose of study treatment. This study is ongoing but not recruiting new patients, and is registered with ClinicalTrials.gov, number NCT02267343. FINDINGS Between Nov 4, 2014, and Feb 26, 2016, we randomly assigned 493 patients to receive nivolumab (n=330) or placebo (n=163). At the data cutoff (Aug 13, 2016), median follow-up in surviving patients was 8·87 months (IQR 6·57-12·37) in the nivolumab group and 8·59 months (5·65-11·37) in the placebo group. Median overall survival was 5·26 months (95% CI 4·60-6·37) in the nivolumab group and 4·14 months (3·42-4·86) in the placebo group (hazard ratio 0·63, 95% CI 0·51-0·78; p<0·0001). 12-month overall survival rates were 26·2% (95% CI 20·7-32·0) with nivolumab and 10·9% (6·2-17·0) with placebo. Grade 3 or 4 treatment-related adverse events occurred in 34 (10%) of 330 patients who received nivolumab and seven (4%) of 161 patients who received placebo; treatment-related adverse events led to death in five (2%) of 330 patients in the nivolumab group and two (1%) of 161 patients in the placebo group. No new safety signals were observed. INTERPRETATION In this phase 3 study, the survival benefits indicate that nivolumab might be a new treatment option for heavily pretreated patients with advanced gastric or gastro-oesophageal junction cancer. Ongoing trials that include non-Asian patients are investigating nivolumab for advanced gastric or gastro-oesophageal junction cancer in various settings and earlier treatment lines. FUNDING Ono Pharmaceutical and Bristol-Myers Squibb.

Clinical Practice Guideline for Accurate Diagnosis and Effective Treatment of Gastrointestinal Stromal Tumor in Korea

Despite the rarity in incidence and prevalence, gastrointestinal stromal tumor (GIST) has emerged as a distinct pathogenetic entity. And the clinical management of GIST has been evolving very rapidly due to the recent recognition of its oncogenic signal transduction pathway and the introduction of new molecular-targeted therapy. Successful management of GIST requires a multidisciplinary approach firmly based on accurate histopathologic diagnosis. However, there was no standardized guideline for the management of Korean GIST patients. In 2007, the Korean GIST study group (KGSG) published the first guideline for optimal diagnosis and treatment of GIST in Korea. As the second version of the guideline, we herein have updated recent clinical recommendations and reflected changes in diagnosis, surgical and medical treatments for more optimal clinical practice for GIST in Korea. We hope the guideline can be of help in enhancing the quality of diagnosis by members of the Korean associate of physicians involving in GIST patientss care and subsequently in achieving optimal efficacy of treatment.

A Prospective, Multicenter, Phase 2 Study of Imatinib Mesylate in Korean Patients with Metastatic or Unresectable Gastrointestinal Stromal Tumor

Objectives: This prospective, multicenter, phase 2 study evaluated the efficacy and safety of imatinib mesylate and assessed KIT and PDGFRA gene mutation status in Korean patients with gastrointestinal stromal tumors (GISTs). Methods: Forty-seven patients with pathologically proven KIT-positive metastatic or unresectable GISTs were accrued from eight institutions in Korea. Imatinib was administered orally at 400 mg once daily. In case of disease progression, the dose was escalated to 600 mg once daily, then 400 mg twice daily. KIT and PDGFRA mutations were analyzed in 29 of the 47 patients. Results: Imatinib produced partial responses in 30 patients (63.8%; 95% confidence interval, 50.1–77.6%) and stable disease in 13 patients (27.7%). The median time to response was 2.6 months (range, 1.0–6.2 months). With a median follow-up of 62 months (range, 32–67 months), 4-year progression-free survival and overall survival rates were 50 and 65%, respectively. The most common adverse events were anemia, neutropenia, edema, and skin rash (predominantly of grade 1–2). There were no treatment-related deaths. In the subset evaluated for mutational status, 24 patients (82.8%) had KIT exon 11 mutations and 1 (3.4%) had a KIT exon 9 mutation. Conclusions: Imatinib is effective and safe in Korean patients with metastatic or unresectable GIST.

Next-generation sequencing reveals somatic mutations that confer exceptional response to everolimus

Background Given the modest responses to everolimus, a mTOR inhibitor, in multiple tumor types, there is a pressing need to identify predictive biomarkers for this drug. Using targeted ultra-deep sequencing, we aimed to explore genomic alterations that confer extreme sensitivity to everolimus. Results We collected formalin-fixed paraffin-embedded tumor/normal pairs from 39 patients (22 with exceptional clinical benefit, 17 with no clinical benefit) who were treated with everolimus across various tumor types (13 gastric cancers, 15 renal cell carcinomas, 2 thyroid cancers, 2 head and neck cancer, and 7 sarcomas). Ion AmpliSeqTM Comprehensive Cancer Panel was used to identify alterations across all exons of 409 target genes. Tumors were sequenced to a median coverage of 552x. Cancer genomes are characterized by 219 somatic single-nucleotide variants (181 missense, 9 nonsense, 7 splice-site) and 22 frameshift insertions/deletions, with a median of 2.1 mutations per Mb (0 to 12.4 mutations per Mb). Overall, genomic alterations with activating effect on mTOR signaling were identified in 10 of 22 (45%) patients with clinical benefit and these include MTOR, TSC1, TSC2, NF1, PIK3CA and PIK3CG mutations. Recurrently mutated genes in chromatin remodeling genes (BAP1; n = 2, 12%) and receptor tyrosine kinase signaling (FGFR4; n = 2, 12%) were noted only in patients without clinical benefit. Conclusions Regardless of different cancer types, mTOR-pathway-activating mutations confer sensitivity to everolimus. Targeted sequencing of mTOR pathway genes facilitates identification of potential candidates for mTOR inhibitors.

Anti-angiogenic Therapy in Patients with Advanced Gastric and Gastroesophageal Junction Cancer: A Systematic Review

Despite advancements in therapy for advanced gastric and gastroesophageal junction cancers, their prognosis remains dismal. Tumor angiogenesis plays a key role in cancer growth and metastasis, and recent studies indicate that pharmacologic blockade of angiogenesis is a promising approach to therapy. In this systematic review, we summarize current literature on the clinical benefit of anti-angiogenic agents in advanced gastric cancer. We conducted a systematic search of PubMed and conference proceedings including the American Society of Clinical Oncology, the European Society for Medical Oncology, and the European Cancer Congress. Included studies aimed to prospectively evaluate the efficacy and safety of anti-angiogenic agents in advanced gastric or gastroesophageal junction cancer. Each trial investigated at least one of the following endpoints: overall survival, progression-free survival/time to progression, and/or objective response rate. Our search yielded 139 publications. Forty-two met the predefined inclusion criteria. Included studies reported outcomes with apatinib, axitinib, bevacizumab, orantinib, pazopanib, ramucirumab, regorafenib, sorafenib, sunitinib, telatinib, and vandetanib. Second-line therapy with ramucirumab and third-line therapy with apatinib are the only anti-angiogenic agents so far shown to significantly improve survival of patients with advanced gastric cancer. Overall, agents that specifically target the vascular endothelial growth factor ligand or receptor have better safety profile compared to multi-target tyrosine kinase inhibitors.

Neoadjuvant Imatinib in Locally Advanced Gastrointestinal Stromal Tumors of the Stomach: Report of Three Cases

Neoadjuvant imatinib therapy used to treat locally advanced or metastatic gastrointestinal stromal tumors (GI ST) remains under active investigation. We studied three cases of locally advanced gastric GISTs treated with imatinib on a neoadjuvant basis, followed by a complete surgical resection. Three patients were diagnosed with locally advanced unresectable GIST of the stomach and were started on imatinib 400 mg/day. After the imatinib treatment, partial responses were achieved in all patients and the tumors were considered resectable. Surgical resection was done after 7, 11, and 8 months of imatinib therapy, respectively. In one case, a metastatic liver lesion was detected during the imatinib treatment using computed tomography scans, so the imatinib therapy was maintained for 11 months postoperatively. In the other two patients without distant metastasis, imatinib treatment was not restarted after surgery. Mutational analysis revealed a mutation in exon 11 of the c-kit gene in two patients, and wild-type c-kit and PDGFRA in one patient. During pathology review of all three cases, we noted several features common to imatinib treatment. There was no evidence of tumor recurrence in all three patients at respective follow-up visits of 22, 15, and 7 months. These results suggest that the neoadjuvant imatinib therapy is a potentially curative approach for selected patients with locally advanced GIST.

Prospective Phase II Study of Preoperative Chemoradiation with Capecitabine in Locally Advanced Rectal Cancer

PURPOSE Capecitabine is an attractive oral chemotherapeutic agent that has a radiosensitizing effect and tumor-selectivity. This study was performed to evaluate the efficacy and toxicity of preoperative chemoradiation therapy, when used with oral capecitabine, for locally advanced rectal cancer. MATERIALS AND METHODS A prospective phase II trial of preoperative chemoradiation for locally advanced adenocarcinomas of the lower two-thirds of the rectum was conducted. A radiation dose of 50 Gy over five weeks and a daily dose of 1650 mg/m(2) capecitabine in two portions was administered during the entire course of radiation therapy. Surgery was performed with standardized total mesorectal excision four to six weeks after completion of the chemoradiation. RESULTS Between January 2002 and September 2003, 61 patients were enrolled onto this prospective phase II trial. The pretreatment clinical stages were T3 in 64% (n=39), T4 in 36% (n=22) and N1-2 in 82% (n=50) of these patients. Fifty-six (92%) patients completed the chemoradiation as initially planned and a complete resection performed in 58 (95%). Down-staging was observed in 45 patients (74%) and a pathologic complete response in 6 (10%). Among the 37 patients with tumors located within 5 cm from the anal verge on colonoscopy, 27 (73%) underwent a sphincter-preserving procedure. No grade 3 and 4 proctitis or hematological toxicities were observed. CONCLUSION Preoperative chemoradiation therapy with capecitabine achieved encouraging rates of tumor downstaging and sphincter preservation, with a low toxicity profile. This combined modality can be regarded as a safe and effective treatment for locally advanced rectal cancer.

Evolution of checkpoint inhibitors for the treatment of metastatic gastric cancers: Current status and future perspectives

BACKGROUND Standard treatment options for patients with advanced gastric or gastroesophageal junction cancer (GC/GEJC) are associated with limited efficacy and some toxicity. Recently, immunotherapy with antibodies that inhibit the programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) interaction has emerged as a new treatment option. This manuscript reviews early-phase and late-phase trials of immunotherapy in advanced GC/GEJC. METHODS Searches for studies of immunotherapy in GC/GEJC were performed using PubMed, ClinicalTrials.gov, and abstract databases for select annual congresses. Findings were interpreted based on expert opinion. RESULTS Monotherapy with anti-PD-1/PD-L1 antibodies, including pembrolizumab, nivolumab, avelumab, durvalumab, and atezolizumab, has shown interesting objective response rates (ORRs; 7-26%) across varying GC/GEJC populations, with ORRs potentially higher in PD-L1 + vs PD-L1 - tumors. Safety profiles compare favorably with chemotherapy, with grade ≥3 treatment-related adverse events occurring in 5-17%. Based on a large phase 2 study, pembrolizumab was approved in the United States for third-line treatment of patients with PD-L1 + GC/GEJC. In a phase 3 trial, third-line or later nivolumab increased overall survival vs placebo in an Asian population, leading to regulatory approval in Japan, although other completed phase 3 trials did not show superiority for pembrolizumab or avelumab monotherapy vs chemotherapy. Other trials in advanced GC/GEJC are assessing various anti-PD-1/PD-L1-based strategies, including administration in first-line and later-line settings and as combination (with chemotherapy or agents targeting other immune checkpoint proteins, eg, CTLA-4, LAG-3, and IDO) or switch-maintenance regimens. CONCLUSIONS Anti-PD-1/PD-L1 antibodies have shown encouraging clinical activity in advanced GC/GEJC. Results from ongoing phase 3 trials are needed to further evaluate the potential roles of these agents within the continuum of care.

Severe Imatinib-Associated Skin Rash in Gastrointestinal Stromal Tumor Patients: Management and Clinical Implications

Purpose This study evaluated the incidence of imatinib-associated skin rash, the interventional outcomes of severe rash, and impact of severe rash on the outcomes of imatinib treatment in gastrointestinal stromal tumor (GIST) patients. Materials and Methods A total of 620 patients were administered adjuvant or palliative imatinib for GIST at Asan Medical Center between January 2000 and July 2012. This analysis focused on a group of 42 patients who developed a severe rash requiring major interventions, defined as dose interruption or reduction of imatinib or systemic steroid use. Results Of the 620 patients treated with imatinib, 148 patients (23.9%) developed an imatinib-associated skin rash; 42 patients (6.8%) developed a severe rash requiring major intervention. Of these, 28 patients (66.8%) successfully continued imatinib with interventions. Serial blood eosinophil levels during imatinib treatment were associated with skin rash and severity. A significant association was observed between successful intervention and blood eosinophil level at the time of intervention initiation. In metastatic settings, patients with severe rash requiring major interventions tended to show poorer progression-free survival than patients who did not require major intervention and patients with no rash, although this finding was not statistically significant (p=0.326). Conclusion By aggressive treatment of severe rash through modification of imatinib dose or use of systemic steroid, the majority of patients can continue on imatinib. In particular, imatinib dose intensity can be maintained with use of systemic steroid. Measuring the blood eosinophil levels may be helpful in guiding the management plan for skin rash regarding the intensity and duration of interventions.

Optimal Timing for the Administration of Capecitabine with Preoperative Chemoradiation for Locally Advanced Rectal Cancer

PURPOSE Capecitabine is an oral fluoropyrimidine carbamate and it is known as an effective radiosensitizer. Capecitabine and its metabolite reach their peak concentration in the plasma at 1 approximately 2 hours after a single oral administration of capecitabine and the levels fall rapidly thereafter. To verify the radiosensitizing effect of capecitabine that is based on such pharmacokinetic characteristics, we performed a retrospective analysis on the optimal timing of capecitabine administration with performing preoperative chemoradiation for locally advanced rectal cancer. MATERIALS AND METHODS Among 171 patients who were treated with preoperative radiotherapy and concurrent capecitabine administration for rectal cancer, 56 patients were administered capecitabine at 1~2 hours before radiotherapy (group A), and at other time in the other 115 patients (group B). Total mesorectal excision was done at 4 to 6 weeks after the completion of chemoradiation. The radiosensitizing effect of capecitabine was evaluated on the basis of the pathological response. RESULTS Complete pathological regression of the primary tumor was observed in 12 patients (21.4%) for group A and in 11 patients (9.6%) for group B (p=0.031). Residual disease less than 0.5 cm (a good response) was observed in 19 patients (33.9%) for group A and in 23 patients (20.0%) for group B (p=0.038). On multivariate analysis, the capecitabine ingestion time showed marginal significance. CONCLUSION When performing preoperative chemoradiation for locally advanced rectal cancer, the radiosensitizing effect of capecitabine was enhanced when it was administered 1 hour before radiotherapy.