Hisato Kawakami

Risk Factors for Cisplatin-Induced Nephrotoxicity and Potential of Magnesium Supplementation for Renal Protection

Background Nephrotoxicity remains a problem for patients who receive cisplatin chemotherapy. We retrospectively evaluated potential risk factors for cisplatin-induced nephrotoxicity as well as the potential impact of intravenous magnesium supplementation on such toxicity. Patients and Methods We reviewed clinical data for 401 patients who underwent chemotherapy including a high dose (≥60 mg/m2) of cisplatin in the first-line setting. Nephrotoxicity was defined as an increase in the serum creatinine concentration of at least grade 2 during the first course of cisplatin chemotherapy, as assessed on the basis of National Cancer Institute Common Terminology Criteria for Adverse Events version 4.0. The severity of nephrotoxicity was evaluated on the basis of the mean change in the serum creatinine level. Magnesium was administered intravenously to 67 patients (17%). Results Cisplatin-induced nephrotoxicity was observed in 127 patients (32%). Multivariable analysis revealed that an Eastern Cooperative Oncology Group performance status of 2 (risk ratio, 1.876; P = 0.004) and the regular use of nonsteroidal anti-inflammatory drugs (NSAIDs) (risk ratio, 1.357; P = 0.047) were significantly associated with an increased risk for cisplatin nephrotoxicity, whereas intravenous magnesium supplementation was associated with a significantly reduced risk for such toxicity (risk ratio, 0.175; P = 0.0004). The development of hypomagnesemia during cisplatin treatment was significantly associated with a greater increase in serum creatinine level (P = 0.0025). Magnesium supplementation therapy was also associated with a significantly reduced severity of renal toxicity (P = 0.012). Conclusions A relatively poor performance status and the regular use of NSAIDs were significantly associated with cisplatin-induced nephrotoxicity, although the latter association was marginal. Our findings also suggest that the ability of magnesium supplementation to protect against the renal toxicity of cisplatin warrants further investigation in a prospective trial.

Targeting MET Amplification as a New Oncogenic Driver

Certain genetically defined cancers are dependent on a single overactive oncogene for their proliferation and survival, a phenomenon known as “oncogene addiction”. A new generation of drugs that selectively target such “driver oncogenes” manifests a clinical efficacy greater than that of conventional chemotherapy in appropriate genetically defined patients. MET is a proto-oncogene that encodes a receptor tyrosine kinase, and aberrant activation of MET signaling occurs in a subset of advanced cancers as result of various genetic alterations including gene amplification, polysomy, and gene mutation. Our preclinical studies have shown that inhibition of MET signaling either with the small-molecule MET inhibitor crizotinib or by RNA interference targeted to MET mRNA resulted in marked antitumor effects in cancer cell lines with MET amplification both in vitro and in vivo. Furthermore, patients with non-small cell lung cancer or gastric cancer positive for MET amplification have shown a pronounced clinical response to crizotinib. Accumulating preclinical and clinical evidence thus suggests that MET amplification is an “oncogenic driver” and therefore a valid target for treatment. However, the prevalence of MET amplification has not been fully determined, possibly in part because of the difficulty in evaluating gene amplification. In this review, we provide a rationale for targeting this genetic alteration in cancer therapy.

Molecular Biomarkers in the Personalized Treatment of Colorectal Cancer

Colorectal cancer (CRC) is a disease in which pathogenesis is influenced by genetic and epigenetic events that occur with tumor initiation and progression. Large variation exists in individual patient prognosis and response to chemotherapy, caused by molecular heterogeneity. Certain biomarkers have been identified that can predict clinical outcome beyond tumor staging, and inform treatment selection. Molecular testing is routinely performed in clinical practice for the selection of patients for targeted biological agents or immunotherapy, and is advocated for prognostic stratification. Estimating prognosis can avoid undertreatment or overtreatment and also guide the intensity of patient follow-up. Classifiers of CRC have been developed that integrate genetic and/or epigenetic features. The mutational status of KRAS and BRAF(V600E) oncogenes combined with analysis of the DNA mismatch repair system with/without the CpG island methylator phenotype (CIMP) has been shown to identify colon cancer subtypes with distinct clinical features and prognoses. Gene expression profiling has also been used to subtype CRCs and can overcome the limitations of single/limited gene testing. A recent effort identified 4 consensus molecular subtypes of biological relevance that were associated with different patient outcomes. Efforts to validate and refine these subtypes to include additional genomic features are ongoing. The focus of this article is to highlight molecular markers that can inform clinical decision-making in patients with CRC.

Clinical outcome for EML4-ALK-positive patients with advanced non-small-cell lung cancer treated with first-line platinum-based chemotherapy

BACKGROUND The EML4-ALK fusion oncogene represents a recently identified molecular target in a subset of patients with non-small-cell lung cancer (NSCLC). Limited data have been available, however, on the outcome of first-line platinum-based chemotherapy in patients with EML4-ALK-positive advanced NSCLC who have not been treated with an ALK kinase inhibitor. PATIENTS AND METHODS The efficacy of platinum-based chemotherapy was compared between patients with advanced nonsquamous NSCLC who harbor EML4-ALK and those who harbor EGFR mutations and those with neither molecular abnormality. RESULTS Among 200 patients with advanced nonsquamous NSCLC, 18 (9.0%) were positive for EML4-ALK, 31 (15.5%) harbored EGFR mutations, and 151 (75.5%) were wild type for both abnormalities. Platinum-based combination chemotherapy showed similar efficacies in the EML4-ALK, EGFR mutation, and wild-type cohorts in terms of response rate and progression-free survival, and overall survival in the EML4-ALK cohort closely resembled that in the wild-type cohort. Within the EML4-ALK cohort, patients with variants 1 or 3 of the fusion gene were predominant and did not appear to differ in their sensitivity to the platinum-based regimens. CONCLUSION Patients with EML4-ALK-positive advanced NSCLC manifest an aggressive clinical course similar to that of those with wild-type tumors if the effective targeted therapy is not instituted.BACKGROUND The EML4-ALK fusion oncogene represents a recently identified molecular target in a subset of patients with non-small-cell lung cancer (NSCLC). Limited data have been available, however, on the outcome of first-line platinum-based chemotherapy in patients with EML4-ALK-positive advanced NSCLC who have not been treated with an ALK kinase inhibitor. PATIENTS AND METHODS The efficacy of platinum-based chemotherapy was compared between patients with advanced nonsquamous NSCLC who harbor EML4-ALK and those who harbor EGFR mutations and those with neither molecular abnormality. RESULTS Among 200 patients with advanced nonsquamous NSCLC, 18 (9.0%) were positive for EML4-ALK, 31 (15.5%) harbored EGFR mutations, and 151 (75.5%) were wild type for both abnormalities. Platinum-based combination chemotherapy showed similar efficacies in the EML4-ALK, EGFR mutation, and wild-type cohorts in terms of response rate and progression-free survival, and overall survival in the EML4-ALK cohort closely resembled that in the wild-type cohort. Within the EML4-ALK cohort, patients with variants 1 or 3 of the fusion gene were predominant and did not appear to differ in their sensitivity to the platinum-based regimens. CONCLUSION Patients with EML4-ALK-positive advanced NSCLC manifest an aggressive clinical course similar to that of those with wild-type tumors if the effective targeted therapy is not instituted.

Anti-HER3 monoclonal antibody patritumab sensitizes refractory non-small cell lung cancer to the epidermal growth factor receptor inhibitor erlotinib

Human epidermal growth factor receptor (HER) 3 is aberrantly overexpressed and correlates with poor prognosis in non-small cell lung cancer (NSCLC). Patritumab is a monoclonal antibody against HER3 that has shown promising results in early-phase clinical trials, but an optimal target population for the drug has yet to be identified. In the present study, we examined whether heregulin, a HER3 ligand that is also overexpressed in a subset of NSCLC, can be used as a biomarker to predict the antitumorigenic efficacy of patritumab and whether the drug can overcome the epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI) resistance induced by heregulin. Patritumab sensitivity was associated with heregulin expression, which, when abolished, resulted in the loss of HER3 and AKT activation and growth arrest. Furthermore, heregulin overexpression induced EGFR TKI resistance in NSCLC cells harbouring an activating EGFR mutation, while HER3 and AKT activation was maintained in the presence of erlotinib in heregulin-overexpressing, EGFR-mutant NSCLC cells. Sustained HER3-AKT activation was blocked by combining erlotinib with either anti-HER2 or anti-HER3 antibody. Notably, heregulin was upregulated in tissue samples from an NSCLC patient who had an activating EGFR mutation but was resistant to the TKI gefitinib. These results indicate that patritumab can overcome heregulin-dependent EGFR inhibitor resistance in NSCLC in vitro and in vivo and suggest that it can be used in combination with EGFR TKIs to treat a subset of heregulin-overexpressing NSCLC patients.

Implications of mismatch repair-deficient status on management of early stage colorectal cancer

For primary colorectal cancers (CRCs), tumor stage has been the best predictor of survival after resection and the key determinant of patient management. However, considerable stage-independent variability in clinical outcome is observed that is likely due to molecular heterogeneity. This is particularly important in early stage CRCs where patients can be cured by surgery alone and only a proportion derives benefit from adjuvant chemotherapy. Thus, the identification of molecular prognostic markers to supplement conventional pathologic staging systems has the potential to guide patient management and influence outcomes. CRC is a heterogeneous disease with molecular phenotypes reflecting distinct forms of genetic instability. The chromosomal instability pathway (CIN) is the most common phenotype, accounting for 85% of all sporadic CRCs. Alternatively, the microsatellite instability (MSI) phenotype represents ~15% of all CRCs and is caused by deficient DNA mismatch repair (MMR) as a consequence of germline mutations in MMR genes or, more commonly, epigenetic silencing of the MLH1 gene with frequent mutations in the BRAF oncogene. MSI tumors have distinct phenotypic features and are consistently associated with a better stage-adjusted prognosis compared with microsatellite stable (MSS) tumors. Among non-metastatic CRCs, the difference in prognosis between MSI and MSS tumors is larger for stage II than stage III patients. On the other hand, the predictive impact of MMR status for adjuvant chemotherapy remains a contentious issue in that most studies demonstrate a lack of benefit for 5-fluorouracil (5-FU)-based adjuvant chemotherapy in stage II MSI-H CRCs, whereas it remains unclear in MSI-H stage III tumors. Here, we describe the molecular aspects of the MMR system and discuss the implications of MMR-deficient/MSI-H status in the clinical management of patients with early stage CRC.

The mutant KRAS gene up-regulates BCL-XL protein via STAT3 to confer apoptosis resistance that is reversed by BIM protein induction and BCL-XL antagonism

Background: Activated KRAS-MEK/ERK signaling confers drug resistance. Results: Mutant KRAS up-regulates BCL-XL via STAT3. A MEK inhibitor induces BIM by loss of phosphorylation (Ser69) and interacts synergistically with a BH3 mimetic. Conclusion: STAT3-mediated BCL-XL inhibits apoptosis in mutant KRAS cells that is overcome by a MEK inhibitor and a BH3 mimetic. Significance: STAT3-BCL-XL represents a key mechanism of apoptosis resistance by activated KRAS. In colorectal cancers with oncogenic GTPase Kras (KRAS) mutations, inhibition of downstream MEK/ERK signaling has shown limited efficacy, in part because of failure to induce a robust apoptotic response. We studied the mechanism of apoptosis resistance in mutant KRAS cells and sought to enhance the efficacy of a KRAS-specific MEK/ERK inhibitor, GDC-0623. GDC-0623 was shown to potently up-regulate BIM expression to a greater extent versus other MEK inhibitors in isogenic KRAS HCT116 and mutant KRAS SW620 colon cancer cells. ERK silencing enhanced BIM up-regulation by GDC-0623 that was due to its loss of phosphorylation at Ser69, confirmed by a BIM-EL phosphorylation-defective mutant (S69G) that increased protein stability and blocked BIM induction. Despite BIM and BIK induction, the isogenic KRAS mutant versus wild-type cells remained resistant to GDC-0623-induced apoptosis, in part because of up-regulation of BCL-XL. KRAS knockdown by a doxycycline-inducible shRNA attenuated BCL-XL expression. BCL-XL knockdown sensitized KRAS mutant cells to GDC-0623-mediated apoptosis, as did the BH3 mimetic ABT-263. GDC-0623 plus ABT-263 induced a synergistic apoptosis by a mechanism that includes release of BIM from its sequestration by BCL-XL. Furthermore, mutant KRAS activated p-STAT3 (Tyr705) in the absence of IL-6 secretion, and STAT3 knockdown reduced BCL-XL mRNA and protein expression. These data suggest that BCL-XL up-regulation by STAT3 contributes to mutant KRAS-mediated apoptosis resistance. Such resistance can be overcome by potent BIM induction and concurrent BCL-XL antagonism to enable a synergistic apoptotic response.

Human papillomavirus DNA and p16 expression in Japanese patients with oropharyngeal squamous cell carcinoma

Human papillomavirus (HPV) is a major etiologic factor for oropharyngeal squamous cell carcinoma (OPSCC). However, little is known about HPV‐related OPSCC in Japan. During the study, formalin‐fixed, paraffin‐embedded OPSCC specimens from Japanese patients were analyzed for HPV DNA by the polymerase chain reaction (PCR) and for the surrogate marker p16 by immuno‐histochemistry. For HPV DNA‐positive, p16‐negative specimens, the methylation status of the p16 gene promoter was examined by methylation‐specific PCR. Overall survival was calculated in relation to HPV DNA and p16 status and was subjected to multivariate analysis. OPSCC cell lines were examined for sensitivity to radiation or cisplatin in vitro. The study results showed that tumor specimens from 40 (38%) of the 104 study patients contained HPV DNA, with such positivity being associated with tumors of the tonsils, lymph node metastasis, and nonsmoking. Overall survival was better for OPSCC patients with HPV DNA than for those without it (hazard ratio, 0.214; 95% confidence interval, 0.074–0.614; P = 0.002). Multivariate analysis revealed HPV DNA to be an independent prognostic factor for overall survival (P = 0.015). Expression of p16 was associated with HPV DNA positivity. However, 20% of HPV DNA‐positive tumors were negative for p16, with most of these tumors manifesting DNA methylation at the p16 gene promoter. Radiation or cisplatin sensitivity did not differ between OPSCC cell lines positive or negative for HPV DNA. Thus, positivity for HPV DNA identifies a distinct clinical subset of OPSCC with a more favorable outcome in Japanese.

Postprogression survival for first-line chemotherapy in patients with advanced gastric cancer

BACKGROUND With the increasing availability of active agents, the importance of postprogression survival (PPS) has been recognised for several malignancies. However, little is known of PPS in advanced gastric cancer. PATIENTS AND METHODS A literature search identified 43 randomised trials in chemotherapy-naive patients with advanced gastric cancer. We partitioned overall survival (OS) into progression-free survival (PFS) and PPS, and then examined the correlation between median OS and either median PFS or median PPS. The correlation between differences in OS (ΔOS) and those in PFS (ΔPFS) between trial arms was also investigated. RESULTS The average median OS was significantly longer in recent (2006 and later) trials than in older (2005 and earlier) trials (10.60 versus 8.64 months, P < 0.001), as was the average median PPS (5.34 versus 3.74 months, P = 0.001). Median PPS was correlated with median OS for all trials (r = 0.732), and this correlation was more pronounced in recent trials (r = 0.850). By contrast, the correlation between median PFS and median OS was less pronounced in recent trials (r = 0.282), as was that between ΔPFS and ΔOS (r = 0.365). CONCLUSION An increase in median PPS was found in accordance with an increase in median OS in recent trials compared with older trials for patients with advanced gastric cancer.

Phase I trial of OTS11101, an anti-angiogenic vaccine targeting vascular endothelial growth factor receptor 1 in solid tumor

OTS11101 is a novel peptide vaccine that acts as an angiogenesis inhibitor by inducing cytotoxic T lymphocyte (CTL) cells that specifically target vascular endothelial cells expressing vascular endothelial growth factor (VEGF) receptor 1. We conducted a phase I study to evaluate the safety, tolerability, maximum tolerated dose, and pharmacodynamic biomarker status of this vaccine. Nine patients with advanced solid tumors received 1.0, 2.0, or 3.0 mg of OTS11101 subcutaneously, once a week in a 28‐day cycle. Three patients experienced grade 1 injection site reactions, which were the most frequent adverse events. Grade 2 proteinuria and hypertension each occurred in one patient. As other toxicities were generally mild, the maximum tolerated dose was not reached. Furthermore, we explored the induction of specific activated CTLs, and biomarkers related to angiogenesis. A pharmacodynamics study revealed that induction of specific CTLs was observed for a dose of 2.0 and 3.0 mg. The serum concentrations of soluble VEGF receptor 1 and 2 after vaccination increased significantly compared with baseline. A microarray was performed to give a comprehensive analysis of gene expression, suggesting that OTS11101 vaccination resulted in T cell activation in a clinical setting. In conclusion, OTS11101 was well tolerated in patients up to 3.0 mg once weekly and our biomarker analysis suggested that this anti‐angiogenesis vaccine is biologically active. (Cancer Sci 2013; 104: 98–104)