Myocardial metastasis from ZEB1- and TWIST-positive spindle cell carcinoma of the esophagus: A case report.

BACKGROUND: Metastatic cardiac tumors are known to occur more frequently than primary cardiac tumors, however, they often remain asymptomatic and are commonly discovered on autopsy. Malignant tumors with a relatively high frequency of cardiac metastasis include mesothelioma, melanoma, lung cancer, and breast cancer, whereas reports of esophageal cancer with cardiac metastasis are rare. CASE SUMMARY: The case of a 60-year-old man who complained of dysphagia is presented. Upper gastrointestinal endoscopy showed a submucosal tumor-like elevated lesion in the esophagus causing stenosis. Contrast-enhanced computed tomography showed left atrial compression due to the esophageal tumor, multiple liver and lung metastases, and a left pleural effusion. Pathological examination of a biopsy specimen from the esophageal tumor showed spindle-shaped cells, raising suspicion of esophageal sarcoma. The disease progressed rapidly, and systemic chemotherapy was deemed necessary, however, due to his poor general condition, administration of cytotoxic agents was considered difficult. Given his high Combined Positive Score, nivolumab was administered, however, the patient soon died from the disease. The autopsy confirmed spindle cell carcinoma (SCC) of the esophagus and cardiac metastasis with similar histological features. Cancer stem cell markers, ZEB1 and TWIST, were positive in both the primary tumor and the cardiac metastasis. CONCLUSION: To the best of our knowledge, there have been no prior reports of cardiac metastasis of esophageal SCC. This case highlights our experience with a patient with esophageal SCC who progressed rapidly and died from the disease, with the autopsy examination showing cardiac metastasis.

Fragment-Based Discovery of Allosteric Inhibitors of SH2 Domain-Containing Protein Tyrosine Phosphatase-2 (SHP2).

The ubiquitously expressed protein tyrosine phosphatase SHP2 is required for signaling downstream of receptor tyrosine kinases (RTKs) and plays a role in regulating many cellular processes. Genetic knockdown and pharmacological inhibition of SHP2 suppresses RAS/MAPK signaling and inhibit the proliferation of RTK-driven cancer cell lines. Here, we describe the first reported fragment-to-lead campaign against SHP2, where X-ray crystallography and biophysical techniques were used to identify fragments binding to multiple sites on SHP2. Structure-guided optimization, including several computational methods, led to the discovery of two structurally distinct series of SHP2 inhibitors binding to the previously reported allosteric tunnel binding site (Tunnel Site). One of these series was advanced to a low-nanomolar lead that inhibited tumor growth when dosed orally to mice bearing HCC827 xenografts. Furthermore, a third series of SHP2 inhibitors was discovered binding to a previously unreported site, lying at the interface of the C-terminal SH2 and catalytic domains.

Preferential B cell differentiation by combined immune checkpoint blockade for renal cell carcinoma is associated with clinical response and autoimmune reactions.

Combined immune checkpoint blockade (ICB) is effective therapy for renal cell carcinoma (RCC). However, the dynamic changes in circulating B cells induced by combined ICB have not been clarified. The present study prospectively examined 22 patients scheduled to receive ICB for unresectable or metastatic RCC between March 2018 and August 2021. Eleven patients received combined therapy with anti-PD-1 (nivolumab) and anti-CTLA-4 (ipilimumab), and the other 11 patients received nivolumab monotherapy. Comprehensive phenotypes of circulating immune cells obtained prior to and after ICB therapy were analyzed by flow cytometry. Although the proportion of naïve B cells among total B cells was significantly decreased, that of switched memory B cells was significantly increased after combined therapy. In responders, the proportion of B cells among peripheral blood mononuclear cells was significantly higher prior to ICB therapy, and the proportion of switched memory B cells among total B cells tended to increase after ICB therapy. Of note, the proportion of plasmablasts among total B cells was significantly increased after ICB therapy in patients who developed severe immune-related adverse events (irAEs), and the proportion of B cells among peripheral blood decreased significantly. Furthermore, in four of five patients who developed immune-related hypophysitis following combined therapy, anti-pituitary antibody was detected in the serum. These results suggested that immune-related hypophysitis was closely related to the increase in circulating plasmablasts. Collectively, this study suggests that combined ICB promotes the differentiation of B cell populations, which is associated with efficient tumor suppression and development of irAEs.

Discovery of Futibatinib: The First Covalent FGFR Kinase Inhibitor in Clinical Use.

Deregulating fibroblast growth factor receptor (FGFR) signaling is a promising strategy for cancer therapy. Herein, we report the discovery of compound 5 (TAS-120, futibatinib), a potent and selective covalent inhibitor of FGFR1-4, starting from a unique dual inhibitor of mutant epidermal growth factor receptor and FGFR (compound 1). Compound 5 inhibited all four families of FGFRs in the single-digit nanomolar range and showed high selectivity for over 387 kinases. Binding site analysis revealed that compound 5 covalently bound to the cysteine 491 highly flexible glycine-rich loop region of the FGFR2 adenosine triphosphate pocket. Futibatinib is currently in Phase I-III trials for patients with oncogenically driven FGFR genomic aberrations. In September 2022, the U.S. Food & Drug Administration granted accelerated approval for futibatinib in the treatment of previously treated, unresectable, locally advanced, or metastatic intrahepatic cholangiocarcinoma harboring an FGFR2 gene fusion or other rearrangement.

Discovery of a Novel ATP-Competitive MEK Inhibitor DS03090629 that Overcomes Resistance Conferred by BRAF Overexpression in BRAF-Mutated Melanoma.

Patients with melanoma with activating BRAF mutations (BRAF V600E/K) initially respond to combination therapy of BRAF and MEK inhibitors. However, their clinical efficacy is limited by acquired resistance, in some cases driven by amplification of the mutant BRAF gene and subsequent reactivation of the MAPK pathway. DS03090629 is a novel and orally available MEK inhibitor that inhibits MEK in an ATP-competitive manner. In both in vitro and in vivo settings, potent inhibition of MEK by DS03090629 or its combination with the BRAF inhibitor dabrafenib was demonstrated in a mutant BRAF-overexpressing melanoma cell line model that exhibited a higher MEK phosphorylation level than the parental cell line and then became resistant to dabrafenib and the MEK inhibitor trametinib. DS03090629 also exhibited superior efficacy against a melanoma cell line-expressing mutant MEK1 protein compared with dabrafenib and trametinib. Biophysical analysis revealed that DS03090629 retained its affinity for the MEK protein regardless of its phosphorylation status, whereas the affinity of trametinib declined when the MEK protein was phosphorylated. These results suggest that DS03090629 may be a novel therapeutic option for patients who acquire resistance to the current BRAF- and MEK-targeting therapies.

OX40 and LAG3 are associated with better prognosis in advanced gastric cancer patients treated with anti-programmed death-1 antibody.

BACKGROUND: Anti-PD-1 monoclonal antibody, nivolumab, has shown efficacy for advanced gastric cancer (AGC). However, the specific immune cell subsets predominantly activated during the period of anti-PD-1 therapy for AGC have not been clarified. METHODS: Peripheral blood of 30 AGC patients treated with nivolumab was prospectively obtained before the initial and second administrations and at the time of progressive disease (PD). The proportions of immune cell subsets and the serum concentrations of cytokines were systematically analysed by flow cytometry. Associations of subsets and serum cytokines with therapeutic effects were evaluated. RESULTS: After the initial administration, significant increases in activated central/effector memory, activated effector T cells, and activated T-helper 1 subsets were observed. At the time of PD, activated regulatory T cells, LAG3-positive CD4+/CD8+ T cells, and TIM3-positive CD4+/CD8+ T cells increased significantly. Significant positive correlations were shown between progression-free survival and proportions of LAG3-positive CD4+/CD8+ T cells and of OX40-positive CD4+/CD8+ T cells (log-rank p = 0.0008, 0.0003, 0.0035 and 0.0040). CONCLUSIONS: Nivolumab therapy enhances activation of central/effector memory and effector subsets of CD4+/CD8+ T cells. The expression levels of LAG-3 and OX40 on T cells correlated with the efficacy of nivolumab therapy and could be reasonable biomarkers for anti-PD-1 therapy.

Hyaluronic acid gel injection in rectovaginal septum reduced incidence of rectal bleeding in brachytherapy for gynecological malignancies.

PURPOSE: The purpose of this study was to report our initial clinical results of hyaluronic acid gel injection (HGI) in the rectovaginal septum (RVS) to reduce the incidence of rectal bleeding in vaginal brachytherapy for gynecologic malignancies. METHODS AND MATERIALS: Since 2008, CT based image-guided adaptive brachytherapy (IGABT) was initiated, and since 2015, HGI in the RVS was introduced in our institution. Vaginal cylinder with or without tandem or additional interstitial needles were applied for patients with gynecologic malignancies. Rectum dosimetric parameters and incidence of late rectum bleeding were compared between patients with and without HGI in the RVS. RESULTS: Between May 2008 and October 2017, 83 patients with gynecologic malignancies were treated with IGABT involving vaginal cylinder. Eleven patients who were treated for palliative intention were excluded, and 72 patients were subjected to the analysis. Of the total 72 patients 46 were with uterine cervical cancer, 19 uterine corpus cancer, five vaginal cancer, one vulvar cancer, and one ovarian cancer. Fifteen and 57 patients were irradiated with and without HGI in the RVS, respectively. With a median follow-up period of 57.7 (4.7-123.1) months, 30 (41.7%) patients suffered from radiation-related rectal bleeding. Patients with HGI in the RVS had a statistically significant lower incidence of rectal bleeding compared with those without it (13.3% vs. 49.1%, p = 0.01). CONCLUSIONS: HGI in the RVS reduced the incidence of late rectal bleeding for patients with gynecologic malignancies treated by vaginal cylinder and was not associated with HGI-procedure-related adverse events.

Discovery of Novel Pyrido-pyridazinone Derivatives as FER Tyrosine Kinase Inhibitors with Antitumor Activity.

To obtain a new anticancer drug, we focused on FER tyrosine kinase. Starting with high-throughput screening with our in-house chemical library, compound 1, which has a pyridine moiety, was found. Referring to their X-ray crystal structure with FES proto-oncogene tyrosine kinase, as a surrogate of FER followed by chemical modification including scaffold hopping of the pyridine template, we discovered pyrido-pyridazinone derivatives with potent FER kinase inhibitory activity. Here, we disclose the structure-activity relationship on the scaffold and representative compound 21 (DS21360717), which showed in vivo antitumor efficacy in a subcutaneous tumor model.

[Efforts toward Patient Safety: Development of System and Education of Non-Technical Skill].

Advanced radiotherapy such as intensity-modulated radiotherapy offers many advantages of high accuracy and efficiency of radiotherapy. To date, many technical guidelines with description of quality assurance and quality control have been reported. However, some reports indicated that human factor and environment is major cause of radiotherapy incidents. If radiotherapy systems depend on automation and computer system, individual risk management is degraded and ability of preventing radiotherapy incidents weaken. Recently, the American Association of Physicists in Medicine (AAPM) task group-100 was reported and it has a new concept guideline, which proposed the comprehensive risk management and education of non-technical skills for overall radiotherapy processes. The TG-100 recommends implementation of process map, reporting system, risk assessment such as failure mode and effects analysis (FMEA) and fault tree analysis (FTA) especially for advanced radiotherapy. In this paper, we described effective and efficient procedures to improve the treatment processes and education of non-technical skills using the such management tools proposed by the TG-100 guide-lines.

The risk factors for oxaliplatin-induced peripheral sensory neuropathy and thrombocytopenia in advanced gastric cancer.

PURPOSE: Peripheral sensory neuropathy (PSN) and thrombocytopenia are the main dose-limiting toxicities of oxaliplatin for the treatment of advanced gastric cancer (AGC). Because the risk factors for those toxicities in practice have not been clarified, we conducted this prospective study. METHODS: AGC patients who received oxaliplatin-based therapy at any of seven institutions participating in the Kyushu Medical Oncology Group were assessed after we obtained written informed consent. RESULTS: A total of 60 patients including 39 males and 21 females were examined. The median age was 66 years. The numbers of patients receiving oxaliplatin as the first, second, or third and later lines of therapy were 39, 16, and 5, respectively. An initial dose of 130, 100, or < 100 mg/m2 oxaliplatin was administered to 12, 39, and 9 patients, respectively. S-1 or capecitabine as a concomitant drug was administered in 54 and 6 patients, respectively. In multivariate analysis, the comorbidity of diabetes mellitus was associated with ≥ grade 2 thrombocytopenia (p = 0.035). No significant risk factor was associated with ≥ grade 2 PSN. However, the accumulated dose of oxaliplatin exhibited a strong correlation with ≥ grade 2 PSN (p = 0.0043), and the predicted accumulated dose of oxaliplatin in which 10% of patients developed ≥ grade 2 PSN was 800 mg/m2. The frequency of PSN in subsequent paclitaxel therapy in patients with ≥ grade 2 or worse PSN in oxaliplatin-based chemotherapy did not increase compared to those with none or grade 1 PSN in oxaliplatin. CONCLUSION: Thrombocytopenia in AGC patients with diabetes mellitus should be carefully monitored during oxaliplatin-based therapy.

A phase 2 study of fosaprepitant combined with high-dose dexamethasone for Japanese cancer patients receiving highly emetogenic chemotherapy.

PURPOSE: Combination therapy of fosaprepitant, dexamethasone (DEX) and a serotonin (5-HT3) receptor antagonist is a standard antiemetic prophylaxis for patients receiving highly emetogenic chemotherapy (HEC). However, the appropriate dose of DEX has not been established in Japan. This study determined the efficacy and safety of triplet antiemetic prophylaxis in Japanese patients receiving HEC when administered the same doses of DEX as those given in a previous international phase 3 study on this drug. METHODS: To assess the efficacy and safety of a sufficient dose of DEX (12 mg on day 1, 8 mg on day 2, 16 mg on days 3 and 4) in combination with intravenous fosaprepitant and granisetron, we prospectively examined patients receiving HEC including cisplatin (≥50 mg/m). The primary endpoint was to determine the percentage of patients who had achieved a complete response (CR), which was defined as no vomiting and no rescue therapy during the entire treatment course. RESULTS: Between February 2013 and January 2015, 44 patients were enrolled with a median age of 65 years (range, 30-75). There were 34 males (77.3%) in the study. Most of the patients had upper gastrointestinal cancers. The CR rate during the treatment course was 70% (95% confidence interval [CI]: 55%-83%) in the overall phase and 91% (95% CI: 78%-97%) in the acute phase and 70% (95% CI: 55%-83%) in the delayed phase. Appreciable severe toxicities related to the antiemetic therapy were not observed. CONCLUSIONS: These results suggest that a sufficient dose of DEX in combination with fosaprepitant and granisetron is optimal as an antiemetic prophylaxis for Japanese patients receiving HEC.

Suggestion of added value by bevacizumab to chemotherapy in patients with unresectable or recurrent small bowel cancer.

PURPOSE: Standard therapy for advanced small bowel adenocarcinoma (SBA) has not yet been established. The present study assessed the efficacy and safety of chemotherapy (CT) in association with molecular targeting approaches for SBA. METHODS: The histories of 33 advanced SBA patients from six different institutions in Japan, who received CT from 2008 to 2016, were retrospectively examined for background, clinical course and outcome. RESULTS: Median patient age was 65 years (range 39-83). Primary tumor was located in the duodenum in 21 patients (67%), the ampulla of Vater in three patients (9%), the jejunum in seven patients (21%) and the ileum in one patient (3%). Histologically, well-to-moderately and poorly differentiated adenocarcinoma were identified in 20 (61%) and nine (27%) patients, respectively. Thirteen patients received a single CT regimen, seven patients received two types of CT regimen, and 13 patients received three or more CT regimens. As first-line CT, modified FOLFOX6, capecitabine plus oxaliplatin, and S-1 plus cisplatin were employed in 13, 1, and 4 patients, respectively. The response rate (RR) and median progression-free survival (PFS) were 25% and 6.0 months, respectively. Median overall survival (OS) was 13.0 months. Nine out of the 33 patients received bevacizumab-containing CT and three received cetuximab-containing CT. Median OS of bevacizumab-containing CT patients was 21.9 months. No unexpected serious adverse events were observed. CONCLUSIONS: The analysis indicates that combination CT for advanced SBA is associated with modest efficacy and safety, and bevacizumab-containing CT may contribute to favorable outcome in these patients.

Efficacy and Safety Analysis of Oxaliplatin-based Chemotherapy for Advanced Gastric Cancer.

BACKGROUND: Significant efficacy of oxaliplatin-based chemotherapy has been demonstrated for advanced gastric cancer (AGC). However, the appropriate dose of oxaliplatin, and the efficacy and toxicity of administration of oxaliplatin subsequent to cisplatin therapy still remain unclear. PATIENTS AND METHODS: In total, 55 patients with AGC that were scheduled to receive oxaliplatin-based chemotherapy were prospectively examined. RESULTS: The median age was 67 years and oxaliplatin was administered to 39 (71%) patients as first-line and in 16 (29%) patients as second-line therapy. An initial dose of 130 or 100 mg/m2 of oxaliplatin was administered to 11 and 36 patients, respectively. The overall response rates (ORR) and median progression free survival (mPFS) were 86 and 33%, and 7.2 and 7.8 months, respectively. Compared to 100 mg/m2, the relative dose intensity was significantly lower and severe toxicity tended to increase with oxaliplatin at 130 mg/m2 A total of 10 patients (18%) had a prior cisplatin-based therapy. The ORR of the patients pretreated with cisplatin was 14% and the mPFS was 6.1 months. CONCLUSION: An initial oxaliplatin dose of 130 mg/m2 resulted in a good response, but tended to increase the risk of toxicity. Subsequent oxaliplatin-based therapy after cisplatin exhibited modest efficacy, especially in cases with cisplatin intolerance.

Favorable control of advanced colon adenocarcinoma with severe bone marrow metastasis: A case report.

Colorectal cancer (CRC) has a propensity to metastasize to the liver, lungs and regional abdominal lymph nodes, but rarely to the bone marrow. A 60-year-old man presented to the National Hospital Organization Kyushu Cancer Center with a 4-week history of persistent lower back pain, anorexia and difficulty defecating. Complete blood count revealed severe thrombocytopenia and erythroblastosis, suggesting a hematological malignancy. However, the bone marrow examination demonstrated involvement by a moderately to poorly differentiated adenocarcinoma, but no hematopoietic abnormalities. A computed tomography scan revealed thickening of the wall of the sigmoid colon, with para-aortic, hilar, mediastinal and supraclavicular lymphadenopathy. The patient was thus diagnosed with sigmoid colon adenocarcinoma with lymph node and bone marrow metastasis. Modified FOLFOX6 was promptly initiated, with concurrent therapy for disseminated intravascular coagulation (DIC). An increased number of thrombocytes was observed on day 6. After 3 cycles of treatment, the patient recovered from DIC and the levels of serum carcinoembryonic antigen and cytokeratin 19 fragment were decreased. Tumor biopsy during colonoscopy following recovery from DIC demonstrated poorly differentiated adenocarcinoma with mucin production, without mutations in the RAS, BRAF or PIK3CA genes, and a cytokeratin (CK) 7-negative, CK20-positive phenotype. The patient has been treated with chemotherapy for 150 days without disease progression. However, the efficacy of chemotherapy for rarely encountered bone marrow metastasis from CRC is poor. The present case was favorably maintained on chemotherapy and survived for 10 months.

Retrospective analysis of cardiovascular diseases related to chemotherapies for advanced solid tumor patients.

Appropriate management of cardiovascular diseases (CVDs) related to chemotherapy for solid tumors is important for safe oncologic treatment. However, prediction of the onset and progression of CVDs has not generally been established in Japan. We carried out a retrospective analysis of advanced or recurrent solid tumor patients who received chemotherapies in a single institution. Patient characteristics, chemotherapy regimens, adverse events, CVDs before chemotherapy, and diagnosis of CVDs in association with chemotherapy were assessed. During the period from April 2006 to March 2012, 394 patients were examined. Cardiac diseases (CDs), hypertension (HT), or arterial thrombosis or venous thromboembolism were prevalent in 37 (9.4%), 22 (5.6%), five (1.3%), and 14 (3.5%) cases, respectively. HT (14.5%) and venous thrombosis (5.8%) were frequent in patients who received bevacizumab-containing chemotherapy. Four cases with left ventricular dysfunction experienced a decrease of ejection fraction and early filling/atrial filling (E/A) and E/A tended to decrease before ejection fraction. Ninety (62.1%) of 145 cases showed an increase in the D-dimer (DD) level before chemotherapy, and a further increase in DD level was found when venous thrombosis occurred. Relative risks of the disease progression of HT, CD, and thromboembolism because of chemotherapy were 1.3, 1.9, and 3.6, respectively. A decrease in E/A and an increase in DD were suggested to be valuable for early diagnosis of the respective onsets of left ventricular dysfunction and venous thrombosis related to chemotherapy. We conclude that patients with previous CD tend to have disease progression of CD during chemotherapy.

Efficacy and Safety of TAS-102 in Clinical Practice of Salvage Chemotherapy for Metastatic Colorectal Cancer.

BACKGROUND: TAS-102 is an anti-metabolite which demonstrated activity against multidrug-resistant advanced colorectal cancer. Its major toxicities are hematological disorders. PATIENTS AND METHODS: Background, TAS-102 efficacy, toxicities and outcomes for patients with multidrug-resistant advanced colorectal cancer from six Institutions of the Kyushu Medical Oncology Group were retrospectively surveyed. RESULTS: Forty-three patients, including fragile patients due to declining performance status and other comorbidities (37%) were analyzed. Efficacy was reflected in an objective overall response of 3%, median progression-free survival of 74 days (2.5 months) and median overall survival of 229 days (7.6 months). The most frequent Common Terminology Criteria for Adverse Events grade 3/4 adverse events were neutropenia (44%), leukopenia (26%) and anemia (23%). Febrile neutropenia was found in 7%. Sub-group analysis demonstrated an improved outcome on treatment with the sequence regorafenib-TAS-102. CONCLUSION: TAS-102 was safely administered to modestly fragile patients with equivalent efficacy to that for the non-fragile population. Further investigation of sequential treatment using regorafenib and TAS-102 is needed.

Efficacy and safety analysis of chemotherapy for advanced colitis-associated colorectal cancer in Japan.

Chemotherapy for advanced colitis-associated colorectal cancer (CAC) has been insufficiently evaluated. The goal of this study was to clarify the efficacy and safety of chemotherapy for CAC in Japan. CAC patients who were treated with chemotherapy between 2005 and 2015 were retrospectively examined. Twenty-nine patients (median age, 48 years; 23 men) were assessed. Eighteen patients had ulcerative colitis, and 11 had Crohn's disease. Three ulcerative colitis and four Crohn's disease patients were in the active disease phase. Primary tumors were located in the rectum/anus (n=16), the left colon (n=9), or the right colon (n=4). Palliative or adjuvant chemotherapy was performed in 13 and 16 patients, respectively. First-line palliative chemotherapy regimens were as follows: fluorouracil, leucovorin, and oxaliplatin (FOLFOX; n=6), FOLFOX+bevacizumab (n=3), and others (n=4). Adjuvant chemotherapy regimens were S-1 (n=7), oxaliplatin-based (n=4) and others (n=5). In palliative chemotherapy, the objective response rate was 15%, and the median progression-free survival and overall survival were 182 and 315 days, respectively. In adjuvant chemotherapy, the 5-year relapse-free survival rate was 78%. Grade 3/4 adverse events (AEs) were observed in 16 patients (55%). Active and remission inflammatory bowel disease patients suffered grade 3/4 nonhematological AEs at an incidence of 71 and 23%, respectively (P<0.01). Dose reduction was required in 11 patients (38%), eight of whom required it for hematological AEs. Adjuvant chemotherapy for CAC exhibited sufficient efficacy, whereas modest efficacy was shown for palliative chemotherapy for CAC. AEs, particularly nonhematological AEs, were closely associated with disease activity of colitis.

Reduced dose of salvage-line regorafenib monotherapy for metastatic colorectal cancer in Japan.

BACKGROUND: Salvage-line regorafenib monotherapy exhibited a marked survival benefit for metastatic colorectal cancer (mCRC). However, the toxicity of this regimen has resulted in the clinical use of a reduced dose of regorafenib. PATIENTS AND METHODS: Thirty-two Japanese mCRC patients (median age=61 years) who had been treated with regorafenib were retrospectively examined. RESULTS: Best objective response rate was 0% and stable disease (SD) was 31%. Median progression-free survival was 81 days and median overall survival was 233 days. Adverse events of any grade were observed in all patients: 17 (53%) patients suffered grade 3 or 4 adverse events including fatigue (13%), anorexia (13%), hand-foot skin reaction (22%) and elevations of alanine aminotransferase/aspartate aminotransferase (19%/16%). One patient with grade 5 liver dysfunction was identified (3%). Twenty-nine (91%) patients required treatment dose reduction or a delay in treatment. The relative dose intensity was 59%. Regorafenib treatments were terminated because of disease progression (59%) or adverse events (34%). CONCLUSION: Despite a decrease in the intensity of regorafenib treatment, because of severe adverse events, a fairly favorable efficacy was achieved in Japanese patients.

TAS-116, a highly selective inhibitor of heat shock protein 90α and ß, demonstrates potent antitumor activity and minimal ocular toxicity in preclinical models.

The molecular chaperone HSP90 plays a crucial role in cancer cell growth and survival by stabilizing cancer-related proteins. A number of HSP90 inhibitors have been developed clinically for cancer therapy; however, potential off-target and/or HSP90-related toxicities have proved problematic. The 4-(1H-pyrazolo[3,4-b]pyridine-1-yl)benzamide TAS-116 is a selective inhibitor of cytosolic HSP90α and ß that does not inhibit HSP90 paralogs such as endoplasmic reticulum GRP94 or mitochondrial TRAP1. Oral administration of TAS-116 led to tumor shrinkage in human tumor xenograft mouse models accompanied by depletion of multiple HSP90 clients, demonstrating that the inhibition of HSP90α and ß alone was sufficient to exert antitumor activity in certain tumor models. One of the most notable HSP90-related adverse events universally observed to differing degrees in the clinical setting is visual disturbance. A two-week administration of the isoxazole resorcinol NVP-AUY922, an HSP90 inhibitor, caused marked degeneration and disarrangement of the outer nuclear layer of the retina and induced photoreceptor cell death in rats. In contrast, TAS-116 did not produce detectable photoreceptor injury in rats, probably due to its lower distribution in retinal tissue. Importantly, in a rat model, the antitumor activity of TAS-116 was accompanied by a higher distribution of the compound in subcutaneously xenografted NCI-H1975 non-small cell lung carcinoma tumors than in retina. Moreover, TAS-116 showed activity against orthotopically transplanted NCI-H1975 lung tumors. Together, these data suggest that TAS-116 has a potential to maximize antitumor activity while minimizing adverse effects such as visual disturbances that are observed with other compounds of this class.

The role of extrahepatic metabolism in the pharmacokinetics of the targeted covalent inhibitors afatinib, ibrutinib, and neratinib.

Despite the fact that much progress has been made recently in the development of targeted covalent inhibitors (TCIs), their pharmacokinetics (PK) have not been well characterized in the light of extrahepatic clearance (CLextH) by glutathione (GSH)/glutathione S-transferase (GST)-dependent conjugation attributable to the unique electrophilic structure (e.g., acrylamide moiety) of TCI compounds. In the present study, CLextH values were examined in rat, dog, and monkey to predict the contribution of CLextH to the PK of the TCIs afatinib, ibrutinib, and neratinib in humans. Afatinib and neratinib both underwent extensive conjugation with GSH in buffer and cytosol fractions of liver and kidney, whereas ibrutinib showed much lower reactivity/susceptibility to GSH/GST-dependent conjugation. The CLextH in each species was calculated from the difference between observed total body clearance and predicted hepatic clearance (CLH) in cryopreserved hepatocytes suspended in 100% serum of the corresponding species. The power-based simple allometry relating the CLextH for the unbound compound to animal body weight was applicable across species for afatinib and neratinib (R(2) ≥ 0.9) but not for ibrutinib (R(2) = 0.04). The predicted AUC after oral administration of afatinib and neratinib agreed reasonably closely with reported values in phase I dose-escalation studies. Comparisons of CLextH and CLH predicted that CLextH largely determined the PK of afatinib (>90% as a proportion of total body clearance) and neratinib (∼34%) in humans. The present method can serve as one of the tools for the optimization of PK in humans at the discovery stage for the development of TCI candidates.