Ipilimumab for Patients with Relapse after Allogeneic Transplantation.

BACKGROUND: Loss of donor-mediated immune antitumor activity after allogeneic hematopoietic stem-cell transplantation (HSCT) permits relapse of hematologic cancers. We hypothesized that immune checkpoint blockade established by targeting cytotoxic T-lymphocyte-associated protein 4 with ipilimumab could restore antitumor reactivity through a graft-versus-tumor effect. METHODS: We conducted a phase 1/1b multicenter, investigator-initiated study to determine the safety and efficacy of ipilimumab in patients with relapsed hematologic cancer after allogeneic HSCT. Patients received induction therapy with ipilimumab at a dose of 3 or 10 mg per kilogram of body weight every 3 weeks for a total of 4 doses, with additional doses every 12 weeks for up to 60 weeks in patients who had a clinical benefit. RESULTS: A total of 28 patients were enrolled. Immune-related adverse events, including one death, were observed in 6 patients (21%), and graft-versus-host disease (GVHD) that precluded further administration of ipilimumab was observed in 4 patients (14%). No responses that met formal response criteria occurred in patients who received a dose of 3 mg per kilogram. Among 22 patients who received a dose of 10 mg per kilogram, 5 (23%) had a complete response, 2 (9%) had a partial response, and 6 (27%) had decreased tumor burden. Complete responses occurred in 4 patients with extramedullary acute myeloid leukemia and 1 patient with the myelodysplastic syndrome developing into acute myeloid leukemia. Four patients had a durable response for more than 1 year. Responses were associated with in situ infiltration of cytotoxic CD8+ T cells, decreased activation of regulatory T cells, and expansion of subpopulations of effector T cells in the blood. CONCLUSIONS: Our early-phase data showed that administration of ipilimumab was feasible in patients with recurrent hematologic cancers after allogeneic HSCT, although immune-mediated toxic effects and GVHD occurred. Durable responses were observed in association with several histologic subtypes of these cancers, including extramedullary acute myeloid leukemia. (Funded by the National Institutes of Health and others; ClinicalTrials.gov number, NCT01822509.).

Neoadjuvant chemotherapy with docetaxel, nedaplatin, and fluorouracil for resectable esophageal cancer: A phase II study.

Cisplatin plus 5-fluorouracil is regarded as standard neoadjuvant chemotherapy for esophageal squamous cell carcinoma (ESCC) in Japan, but the prognosis remains poor. We have previously described how definitive chemoradiotherapy with docetaxel, nedaplatin, and 5-fluorouracil (DNF) led to a very high response rate and promising survival times. We therefore undertook a phase II trial to evaluate the feasibility and efficacy of neoadjuvant DNF. The study included patients with clinical stage Ib-III ESCC. Chemotherapy consisted of i.v. docetaxel (30 mg/m2 ) and nedaplatin (50 mg/m2 ) on days 1 and 8, and a continuous infusion of 5-fluorouracil (400 mg/m2 /day) on days 1-5 and 8-12, every 3 weeks. After three courses of chemotherapy, esophagectomy was carried out. The primary end-point was the completion rate of the protocol treatment. Twenty-eight patients were enrolled (cStage Ib/II/III, 2/3/23) and all received at least two cycles of chemotherapy. Twenty-five patients underwent surgery, all of whom achieved an R0 resection, leading to a completion rate of 89.3%. The overall response rate was 87.0%. A pathological complete response was confirmed in eight (32.0%) cases. Grade 3/4 adverse events included leukopenia (32.1%), neutropenia (39.3%), febrile neutropenia (10.7%), thrombocytopenia (10.7%), and diarrhea (14.3%), but were manageable. Treatment-related deaths and major surgical complications did not occur. Estimated 2-year progression-free and overall survival rates were 70.4% and 77.2%, respectively. Thus, DNF therapy was well tolerated and deemed feasible, with a strong tumor response in a neoadjuvant setting for ESCC. This trial is registered with the University Hospital Medical Information Network (UMIN ID: 000014305).

Conversion therapy for inoperable advanced gastric cancer patients by docetaxel, cisplatin, and S-1 (DCS) chemotherapy: a multi-institutional retrospective study.

BACKGROUND: Conversion therapy is an option for unresectable metastatic gastric cancer when distant metastases are controlled by chemotherapy; however, the feasibility and efficacy remain unclear. This study aimed to assess the feasibility and efficacy of conversion therapy in patients with initially unresectable gastric cancer treated with docetaxel, cisplatin, and S-1 (DCS) chemotherapy by evaluating clinical outcomes. METHODS: One hundred unresectable metastatic gastric cancer patients, enrolled in three DCS chemotherapy clinical trials, were retrospectively evaluated. The patients received oral S-1 (40 mg/m2 b.i.d.) on days 1-14 and intravenous cisplatin (60 mg/m2) and docetaxel (50-60 mg/m2) on day 8 every 3 weeks. Conversion therapy was defined when the patients could undergo R0 resection post-DCS chemotherapy and were able to tolerate curative surgery. RESULTS: Conversion therapy was achieved in 33/100 patients, with no perioperative mortality. Twenty-eight of the 33 patients (84.8 %) achieved R0 resection, and 78.8 % were defined as histological chemotherapeutic responders. The median overall survival (OS) of patients who underwent conversion therapy was 47.8 months (95 % CI 28.0-88.5 months). Patients who underwent R0 resection had significantly longer OS than those who underwent R1 and R2 resections (P = 0.0002). Of the patients with primarily unresectable metastases, 10 % lived >5 years. Among patients who underwent conversion therapy, multivariate analysis showed that the pathological response was a significant independent predictor for OS. CONCLUSIONS: DCS safely induced a high conversion rate, with very high R0 and pathological response rates, and was associated with a good prognosis; these findings warrant further prospective investigations.

RNAi-mediated gene silencing of ST6GalNAc I suppresses the metastatic potential in gastric cancer cells.

BACKGROUND: ST6GalNAc I is a sialyltransferase controlling the expression of sialyl-Tn antigen (STn), which is overexpressed in several epithelial cancers, including gastric cancer, and is highly correlated with cancer metastasis. However, the functional contribution of ST6GalNAc I to development or progression of gastric cancer remains unclear. In this study, we investigated the effects of suppression of ST6GalNAc I on gastric cancer in vitro and in vivo. METHODS: Gastric cancer cell lines were transfected with ST6GalNAc I siRNA and were examined by cell proliferation, migration, and invasion assays. We also evaluated the effect of ST6GalNAc I siRNA treatment in a peritoneal dissemination mouse model. The differences in mRNA levels of selected signaling molecules were analyzed by polymerase chain reaction (PCR) arrays associated with tumor metastasis in MKN45 cells. The signal transducer and activator of transcription 5b (STAT5b) signaling pathways that reportedly regulate the insulin-like growth factor-1 (IGF-1) were analyzed by Western blot. RESULTS: ST6GalNAc I siRNA inhibited gastric cancer cell growth, migration, and invasion in vitro. Furthermore, intraperitoneal administration of ST6GalNAc I siRNA- liposome significantly inhibited peritoneal dissemination and prolonged the survival of xenograft model mice with peritoneal dissemination of gastric cancer. PCR array confirmed that suppression of ST6GalNAc I caused a significant reduction in expression of IGF-1 mRNA. Decreased IGF-1 expression in MKN45 cells treated with ST6GalNAc I siRNA was accompanied by reduced phosphorylation of STAT5b. CONCLUSION: ST6GalNAc I may regulate the gene expression of IGF-1 through STAT5b activation in gastric cancer cells and may be a potential target for treatment of metastasizing gastric cancer.

[A case of anal variceal bleeding successfully treated with endoscopic injection sclerotherapy].

We report a case of anal variceal bleeding successfully treated with endoscopic injection sclerotherapy (EIS). A 64-year-old man with alcoholic liver cirrhosis was hospitalized because of repeated anal bleeding. Colonoscopy revealed external anal varices connecting with rectal varices. Three days after admission, external anal variceal bleeding was observed. Angiography revealed that the anorectal varices formed by hepatofugal inferior mesenteric vein drained into the internal iliac vein. On angiography, the variceal blood flow rate was extremely low, therefore we performed EIS. Seven days after therapy, thrombosis of anorectal varices was observed.

Case Report: Longitudinal monitoring of clonal evolution by circulating tumor DNA for resistance to anti-EGFR antibody in a case of metastatic colorectal cancer.

Background: Treatment with anti-EGFR antibody has been shown to prolong survival in patients with RAS wild-type metastatic colorectal cancer (mCRC). However, even patients who initially respond to anti-EGFR antibody therapy, almost without exception, develop resistance to the therapy and then fail to respond. Secondary mutations in the mitogen-activated protein (MAPK) signaling pathway (mainly in NRAS and BRAF) have been implicated in anti-EGFR resistance. However, the process by which resistant clones develop during therapy has not been elucidated, and considerable intrapatient and interpatient heterogeneity exists. Circulating tumor DNA (ctDNA) testing has recently allowed the noninvasive detection of heterogeneous molecular alterations that underlie the evolution of resistance to anti-EGFR. In this report, we describe our observation of genomic alterations in KRAS and NRAS in a patient with acquired resistance to anti-EGFR antibody drugs by tracking clonal evolution using serial ctDNA anaylsis. Case presentation: A 54-year-old woman was initially diagnosed with sigmoid colon cancer with multiple liver metastases. After receiving first-line mFOLFOX + cetuximab, second-line FOLFIRI + ramucirumab, third-line trifluridine/tipiracil + bevacizumab, fourth-line regorafenib, and fifth-line CAPOX + bevacizumab, she was rechallenged with CPT-11 + cetuximab. The best response to anti-EGFR rechallenge therapy was a partial response. RAS in the ctDNA was assessed during treatment. The RAS status changed from wild type to mutant type, back to wild type, and again to mutant type (NRAS/KRAS codon 61) during the course of treatment. Conclusion: In this report, tracking of ctDNA allowed us to describe clonal evolution in a case in which we observed genomic alterations in KRAS and NRAS in a patient who acquired resistance to anti-EGFR antibody drugs during treatment. It is reasonable to consider repeat molecular interrogation during progression in patients with mCRC by using ctDNA analysis, which could help to identify patients who may benefit from a rechallenge strategy.

Hilar/mediastinal and cutaneous drug-induced sarcoidosis-like reaction associated with immune checkpoint inhibitors in metastatic colorectal cancer: a case report.

Background: Immune checkpoint inhibitors (ICIs) are the standard treatment for metastatic colorectal cancer (mCRC) with high microsatellite instability (MSI-H). Among immune-related adverse events (irAEs), drug-induced sarcoidosis-like reactions (DISR) are often difficult to differentiate from cancer progression. Main Body: This is a case of a woman in her mid-60s, with mCRC (RAS wild/BRAF mutant/MSI-H) and abdominal lymph node metastasis, treated with four courses of ipilimumab + nivolumab every 3 weeks, followed by nivolumab every 2 weeks as third-line treatment. After treatment, the original lymph node metastases shrank, but hilar/mediastinal lymph nodes appeared. Endoscopic ultrasound-guided fine-needle aspiration of these lymph nodes revealed multiple epithelioid granulomas without necrosis, indicating a sarcoidosis-like reaction. Fluorodeoxyglucose-positron emission tomography scan showed abnormal subcutaneous accumulation in bilateral forearms and bilateral knee joints. Biopsy of the cutaneous lesions was also performed, which revealed epithelioid granulomas. As the patient had no symptoms in other organs, no specific therapeutic intervention was administered. After the discontinuation of immunotherapy, the sarcoidosis-like reaction regressed without cancer relapse. Conclusions: Clinicians should be aware of the possibility of DISR as an irAE during the ICI treatment of mCRC. In suspected cases of DISR following ICI therapy, it is important to differentiate between cancer progression and DISR through histological diagnosis for the subsequent strategy, as radiological and serological findings are not definitive.

In Vitro and In Vivo Assessment of Atemoya Fruit (Annona atemoya) for Food-Drug Interactions.

BACKGROUND AND OBJECTIVES: Atemoya (Annona atemoya) is increasingly being consumed worldwide because of its pleasant taste. However, only limited information is available concerning possible atemoya-drug interactions. In the present study, the issue of whether atemoya shows food-drug interactions with substrate drugs of the major drug-metabolizing cytochrome P450s (i.e., CYP1A2, CYP2C9, and CYP3A) is addressed. METHODS: The ability of atemoya juice to inhibit the activities of phenacetin O-deethylase (CYP1A2), diclofenac 4'-hydroxylase (CYP2C9), and midazolam 1'-hydroxylase (CYP3A) was examined in vitro using human and rat liver microsomes. The in vivo pharmacokinetics of phenacetin and metabolites derived from it in rats when atemoya juice or fluvoxamine (a CYP1A2 inhibitor) was preadministered were also investigated. RESULTS: Atemoya juice significantly inhibited CYP1A2 activity in human liver microsomes, but not the activities of CYP2C9 and CYP3A. In spite of this inhibition, preadministration of atemoya had no effect on the pharmacokinetics of phenacetin, a CYP1A2 substrate, in rats. Meanwhile, preadministration of fluvoxamine significantly extended the time needed for the elimination of phenacetin, possibly due to the inhibition of CYP1A2. This suggests that the intake of an excess amount of atemoya juice is necessary to cause a change in the pharmacokinetics of phenacetin when the IC50 values for CYP1A2 inhibition by atemoya and fluvoxamine are taken into account. CONCLUSION: The results indicate that a daily intake of atemoya would not change the pharmacokinetics of CYP1A2 substrates such as phenacetin as well as CYP2C9- and CYP3A-substrate drugs.

Argon plasma coagulation treatment of hemorrhagic radiation proctopathy: the optimal settings for application and long-term outcome.

BACKGROUND: No standard treatment exists for hemorrhagic radiation proctopathy (HRP). Recently it was reported that argon plasma coagulation (APC) is effective for HRP. However, previous studies documented complications such as ulcers, strictures, and perforations in as many as 20% of APC-treated patients. OBJECTIVE: The aim of this study was to determine the optimal parameters for APC by using swine rectum and to assess the safety and effectiveness of APC in HRP patients. DESIGN: Prospective case series. SETTING: University teaching hospital. PATIENTS: Sixty-five patients with HRP were prospectively enrolled between 2000 and 2010. INTERVENTIONS: APC for HRP. MAIN OUTCOME MEASUREMENTS: Optimal APC parameters, number of treatments, success rate, complications, clinical remissions. RESULTS: APC in swine rectal wall ex vivo was optimal with a 40-W current, 1.2-L/min gas flow rate, and 2-second application, which was sufficient to treat the submucosal telangiectasia but did not adversely affect the muscle layer. Sixty-five patients (46 men, 19 women; median age 72 years) with HRP occurring at a mean of 20 months after radiotherapy were studied. Proctopathy was classified as grade A (mild) in 7 patients (10.8%), grade B (moderate) in 41 (63.1%), and grade C (severe) in 17 (26.2%). The treatment success rate was 98.5% after a median of 2 (range 1-5) APC sessions. The median clinical score for rectal bleeding was significantly decreased after APC (P < .0001), and the hemoglobin level was significantly increased (P < .0001). APC was well tolerated, and no significant side effects or complications occurred. During a mean follow-up of 34.6 months (range 3.6 -121.1 months), 4 patients (6.3%) had minor recurrent rectal bleeding and 60 (93.8%) remained in remission. LIMITATIONS: Nonrandomized study. CONCLUSIONS: HRP treatment with optimal APC settings yields a high success rate and long-lasting clinical remission with no significant complications.

[Tuberculous pleuritis with onset of refractory pleural effusion after chemoradiotherapy for esophageal cancer].

A 75-year-old man received chemoradiotherapy (CRT) for stage IVa esophageal cancer and complete response (CR) was obtained. However, he was referred to our department for recurrence in an area of esophagus not included in the previously irradiated field. Left pleural effusion increased after admission. Tuberculous pleuritis was eventually diagnosed by thoracoscopic pleural biopsy. It is necessary to accurately diagnose the cause of pleural effusion after CRT, because treatment strategies greatly depend on it. It is also necessary to consider the possible onset of tuberculous pleuritis, in particular, in patients with a history of tuberculosis infection.

Endoscopic findings of enteropathy-type T-cell lymphoma by double-balloon enteroscopy and capsule endoscopy.

Enteropathy-type T-cell lymphoma (ETL) is a rare primary intestinal disorder, particularly in Japan, and there have been few reports on the endoscopic findings of the disease. Here we report detailed endoscopic findings of ETL based on double-balloon enteroscopy and capsule endoscopy. Double-balloon enteroscopy and capsule endoscopy may be useful tools for diagnosing and monitoring the effects of therapy in patients with ETL.

Maturation and Phenotypic Heterogeneity of Human CD4+ Regulatory T Cells From Birth to Adulthood and After Allogeneic Stem Cell Transplantation.

CD4+ Regulatory T cells (Treg) play a critical role in maintaining immune homeostasis. Various Treg subsets have been identified, however the heterogeneity of Treg subpopulations during development remains uncharacterized. Using mass cytometry we obtained single cell data on expression of 35 functional markers to examine the heterogeneity of Treg cells at birth and in adults. Unsupervised clustering algorithms FlowSOM and ACCENSE were used to quantify Treg heterogeneity. As expected, Treg in umbilical cord blood were predominately naïve while Treg in adult blood were predominately central memory and effector memory cells. Although umbilical cord blood Treg are mostly naïve cells, we observed multiple phenotypic Treg subsets in cord blood. Nevertheless, peripheral blood in adults contained higher percentages of Treg and the heterogeneity of Treg was significantly increased in adults. We also studied Treg heterogeneity throughout a 2-year period after allogeneic hematopoietic stem cell transplantation (alloHSCT) and in patients with chronic graft-versus-host disease (cGVHD). Treg heterogeneity recovered rapidly after alloHSCT and gradually increased in the first two years post-transplant. However, patients with cGVHD had significantly fewer distinct Treg subpopulations, proposing a correlation between a disrupted Treg heterogeneity and cGVHD. Our study is the first to compare human Treg heterogeneity at birth, in healthy adults and in patients after alloHSCT with and without cGVHD. This approach to characterize Treg heterogeneity based on expression of a large panel of functional markers may enable future studies to identify specific Treg defects that contribute to immune dysfunction.

Hyperemesis-induced Wernicke-Korsakoff Syndrome due to Hypergastrinemia during Long-term Treatment with Proton Pump Inhibitors.

We herein report a patient with Wernicke-Korsakoff syndrome (WKS) who had neither a history of alcoholism or of history of gastric surgery. A 56-year-old woman was transferred to our hospital because of the loss of consciousness and she was diagnosed to have Wernicke encephalopathy. She showed proton pump inhibitor-induced refractory hypergastrinemia with the subsequent development of hyperemesis and a vitamin B1 deficiency.

Clinical impact of primary tumour location, early tumour shrinkage, and depth of response in the treatment of metastatic colorectal cancer with first-line chemotherapy plus cetuximab or bevacizumab.

The primary tumour location is an important prognostic factor for previously untreated metastatic colorectal cancer (mCRC). However, the predictive efficacies of primary tumour location, early tumour shrinkage (ETS), and depth of response (DpR) on mCRC treatment has not been fully evaluated. This study aimed to investigate the predictive efficacies of these traits in mCRC patients treated with first-line 5-fluorouracil-based chemotherapy plus biologic agents, namely, cetuximab and bevacizumab. This was a retrospective analysis of the medical records of 110 patients with pathology-documented unresectable mCRC. Patients with left-sided mCRC receiving any first-line regimen showed better overall survival (OS) than those with right-sided mCRC [33.3 vs 16.3 months; hazard ratio (HR) 0.44; 95% confidence interval (CI) 0.27-0.74; p < 0.001]. In patients with left-sided tumours, treatment with chemotherapy plus cetuximab yielded longer OS than chemotherapy plus bevacizumab (50.6 vs 27.8 months, HR 0.55; 95% CI 0.32-0.97; p = 0.0378). mCRC patients with ETS and high DpR showed better OS than those lacking ETS and with low DpR (33.5 vs 19.6 months, HR 0.50, 95% CI 0.32-0.79, p = 0.023 and 38.3 vs 19.0 months, HR 0.43, 95% CI 0.28-0.68, p < 0.001, respectively). Moreover, ETS and/or high DpR achieved in patients with right-sided mCRC receiving chemotherapy plus cetuximab were associated with significantly better OS than in those lacking ETS and with low DpR (34.3 vs 10.4 months, HR 0.19, 95% CI 0.04-0.94, p = 0.025 and 34.3 vs 10.4 months, HR 0.19, 95% CI 0.04-0.94, p = 0.0257, respectively). Taken together, our study demonstrates that primary tumour location is not only a well-known prognostic factor but also a relevant predictive factor in patients with mCRC receiving chemotherapy plus cetuximab. Additionally, both ETS and DpR could predict treatment outcomes and also potentially guide cetuximab treatment even in right-sided mCRCs.

FOXO3a Activation by HDAC Class IIa Inhibition Induces Cell Cycle Arrest in Pancreatic Cancer Cells.

OBJECTIVES: Pancreatic cancer (PC) is highly aggressive with multiple oncogenic mutations. The efficacy of current chemotherapy is poor, and new therapeutic targets are needed. The forkhead box (FOX) proteins are multidirectional transcriptional factors strongly implicated in malignancies. Their expression is consistently suppressed by several oncogenic pathways such as PI3K/AKT signaling activated in PC. A recent study showed that class IIa histone deacetylases (HDAC) can act as a transcriptional suppressor. In this study, we hypothesized that HDAC class IIa inhibition would upregulate FOXO3a expression, thereby inducing its transcription-dependent antitumor effects. METHODS: We confirmed the change of FOXO3a expression and the effect of the cell growth inhibition by HDAC class IIa inhibition in AsPC-1 cells. Because FOXO3a is subject to ubiquitylation-mediated proteasome degradation, we examined the synergistic activation of FOXO3a by HDAC class IIa selective inhibitor TMP269 combined with proteasome inhibitor carfilzomib. RESULTS: We observed that TMP269 induced FOXO3a expression in a dose-dependent manner and inhibited cell growth in AsPC-1 cells. G1/S arrest was observed. FOXO3a expression was further increased and cell growth inhibition was dramatically enhanced by TMP269 combined with carfilzomib. CONCLUSIONS: Dual inhibition of class IIa HDACs and proteasome could be a promising new strategy for modifying FOXO3a activity against PC.

Case series of three patients with hereditary diffuse gastric cancer in a single family: Three case reports and review of literature.

BACKGROUND: Hereditary diffuse gastric cancer (HDGC) is a familial cancer syndrome often associated with germline mutations in the CDH1 gene. However, the frequency of CDH1 mutations is low in patients with HDGC in East Asian countries. Herein, we report three cases of HDGC harboring a missense CDH1 variant, c.1679C>G, from a single Japanese family. CASE SUMMARY: A 26-year-old female (Case 1) and a 51-year-old male (father of Case 1), who had a strong family history of gastric cancer, were diagnosed with advanced diffuse gastric cancer. After genetic counselling, a 25-year-old younger brother of Case 1 underwent surveillance esophagogastroduodenoscopy that detected small signet ring cell carcinoma foci as multiple pale lesions in the gastric mucosa. Genetic analysis revealed a CDH1 c.1679C>G variant in all three patients. CONCLUSION: It is important for individuals suspected of having HDGC to be actively offered genetics evaluation. This report will contribute to an increased awareness of HDGC.

[A long term survivor of advanced gastric cancer treated with multi-drug combination chemotherapy].

We report a case of 70-year-old man who was admitted to our hospital due to hematemesis in June 2004. He was diagnosed by gastroscopy as having a type III moderately-poorly differentiated adenocarcinoma. A computed tomography (CT) scan revealed multiple lymph nodes swelling (#13, #16), finally he was diagnosed with gastric cancer stage IV (cT3, cN3, cM1). He was treated with S-1, but lymph nodes swelling increased in size, and then in March 2005, the treatment was changed to a second-line chemotherapy consisting of CPT-11 and CDDP. Abdominal CT scan showed a remarkable reduction of #16b1 lymph node, and the second-line chemotherapy was continued until 23 courses. But in April 2007, gastroscopy revealed the enlargement of gastric lesion. He was treated by third-line chemotherapy consisting of paclitaxel and doxifluoridine. This therapy was effective and continued until 7 courses. However, the treatment gradually became resistant and he died in May 2008, which was 4 years since the initial diagnosis.

Total buried bumper syndrome: A case study in transabdominal removal using a technique of endoscopic submucosal dissection.

Tube removal by endoscopic submucosal dissection using needle and insulation-tipped diathermic knives against buried bumper syndrome is a reliable, noninvasive and safe procedure.

A dose-escalation study of docetaxel, oxaliplatin, and S-1 (DOS) as a first-line therapy for patients with unresectable metastatic gastric cancer.

PURPOSE: The aim of this study was to determine the recommended dose (RD) for a docetaxel/oxaliplatin/S-1 (DOS) regimen in patients with unresectable gastric cancer and to preliminarily evaluate its efficacy. METHODS: Previously untreated patients with histologically proven unresectable metastatic gastric cancer were enrolled (n = 16). Docetaxel and oxaliplatin were administered intravenously on day 8 and S-1 was administered orally twice a day on days 1-14. Each cycle was repeated every 3 weeks. Dose-limiting toxicities (DLTs) were evaluated during the first treatment cycle. Three dose escalations of DOS were employed in this study: level 1 (50/100/80 mg/m2), level 2 (50/130/80 mg/m2), and level 3 (60/130/80 mg/m2). RESULTS: According to the 3 + 3 dose-escalating schedule, we determined that the RD and maximum tolerated dose for this regimen were level 1 and level 2, respectively. The DLTs were grade 3 diarrhea and febrile neutropenia. The overall response rate was 78% (7/9) for patients with measurable lesions and consisted of two complete responses and five partial responses. Five patients underwent conversion surgery. The median follow-up time was 19 months with median survival time and progression-free survival being 19.6 months and 7.6 months, respectively. CONCLUSIONS: The results from this study demonstrated the safety and tolerability of DOS in unresectable metastatic gastric cancer patients and revealed promising preliminary efficacy with a high conversion rate. A phase II trial of DOS regimen using the identified RD is ongoing.