In the Shandong Intervention Trial, 2 weeks of antibiotic treatment for Helicobacter pylori reduced the prevalence of precancerous gastric lesions, whereas 7.3 years of oral supplementation with garlic extract and oil (garlic treatment) or vitamin C, vitamin E, and selenium (vitamin treatment) did not. Here we report 14.7-year follow-up for gastric cancer incidence and cause-specific mortality among 3365 randomly assigned subjects in this masked factorial placebo-controlled trial. Conditional logistic regression was used to estimate the odds of gastric cancer incidence, and the Cox proportional hazards model was used to estimate the relative hazard of cause-specific mortality. All statistical tests were two-sided. Gastric cancer was diagnosed in 3.0% of subjects who received H pylori treatment and in 4.6% of those who received placebo (odds ratio = 0.61, 95% confidence interval = 0.38 to 0.96, P = .032). Gastric cancer deaths occurred among 1.5% of subjects assigned H pylori treatment and among 2.1% of those assigned placebo (hazard ratio [HR] of death = 0.67, 95% CI = 0.36 to 1.28). Garlic and vitamin treatments were associated with non-statistically significant reductions in gastric cancer incidence and mortality. Vitamin treatment was associated with statistically significantly fewer deaths from gastric or esophageal cancer, a secondary endpoint (HR = 0.51, 95% CI = 0.30 to 0.87; P = .014).

AIM: To evaluate effects of UDP-glucuronosyltransferase1A1 (UGT1A1) and thymidylate synthetase (TS) gene polymorphisms on irinotecan in metastatic colorectal cancer (mCRC).

METHODS: Two irinotecan- and fluorouracil-based regimens, FOLFIRI and IFL, were selected as second-line therapy for 138 Chinese mCRC patients. Genomic DNA was extracted from peripheral blood samples before treatment. UGT1A1 and TS gene polymorphisms were determined by direct sequencing and restriction fragment length polymorphism, respectively. Gene polymorphisms of UGT1A1*28, UGT1A1*6 and promoter enhancer region of TS were analyzed. The relationship between genetic polymorphisms and clinical outcome, that is, response, toxicity and survival were assessed. Pharmacokinetic analyses were performed in a subgroup patients based on different UGT1A1 genotypes. Plasma concentration of irinotecan and its active metabolite SN-38 and inactive metabolite SN-38G were determined by high performance liquid chromatography. Differences in irinotecan and its metabolites between UGT1A1 gene variants were compared.

RESULTS: One hundred and eight patients received the FOLFIRI regimen, 29 the IFL regimen, and one irinotecan monotherapy. One hundred and thirty patients were eligible for toxicity and 111 for efficacy evaluation. One hundred and thirty-six patients were tested for UGT1A1*28 and *6 genotypes and 125 for promoter enhancer region of TS. Patients showed a higher frequency of wild-type UGT1A1*28 (TA6/6) compared with a Caucasian population (69.9% vs 45.2%). No significant difference was found between response rates and UGT1A1 genotype, although wild-type showed lower response rates compared with other variants (17.9% vs 24.2% for UGT1A1*28, 15.7% vs 26.8% for UGT1A1*6). When TS was considered, the subgroup with homozygous UGT1A1*28 (TA7/7) and non-3RG genotypes showed the highest response rate (33.3%), while wild-type UGT1A1*28 (TA6/6) with non-3RG only had a 13.6% response rate, but no significant difference was found. Logistic regression showed treatment duration was closely linked to clinical response. In toxicity comparison, UGT1A1*28 TA6/6 was associated with lower incidence of grade 2-4 diarrhea (27.8% vs 100%), and significantly reduced the risk of grade 4 neutropenia compared with TA7/7 (7.8% vs 37.5%). Wild-type UGT1A1*6 (G/G) tended to have a lower incidence of grade 3/4 diarrhea vs homozygous mutant (A/A) genotype (13.0% vs 40.0%). Taking UGT1A1 and TS genotypes together, lower incidence of grade 2-4 diarrhea was found in patients with non-3RG TS genotypes, when TA6/6 was compared with TA7/7 (35.3% vs 100.0%). No significant association with time to progression (TTP) and overall survival (OS) was observed with either UGT1A1 or TS gene polymorphisms, although slightly longer TTP and OS were found with UGT1A1*28 (TA6/6). Irinotecan PK was investigated in 34 patients, which showed high area under concentration curve (AUC) of irinotecan and SN-38, but low AUC ratio (SN-38G / SN-38) in those patients with UGT1A1*28 TA7/7.

CONCLUSION: A distinct distribution pattern of UGT1A1 genotypes in Chinese patients might contribute to relatively low toxicity associated with irinotecan and 5-fluorouracil in mCRC patients.

Objective

To evaluate the efficacy and toxicity of the combination regimen of paclitaxel, cisplatin and 5-FU (PCF) as first-line or second-line therapy in patients with advanced gastric and esophagogastric junction (EGJ) adenocarcinoma in China.

Methods

The patients were treated with paclitaxel 150 mg/m2 on d1; fractionated cisplatin 15 mg/m2 and continuous infusion 5-FU 600 mg/(m2·d) intravenously on d1-d5 of a 21-d cycle until disease progression or unacceptable toxicities.

Results

Seventy-five patients have been enrolled, among which, 41 received PCF regimen as the first-line therapy (group A) and 34 received the regimen as the second-line therapy (group B) with the median age of 59 years old and Karnofsky performance status (KPS) score ≥80. Toxicities were analyzed in all 75 patients. Seventy-one patients were evaluable for efficacy. The median overall survival (mOS) was 12.0 months (95% CI: 7.9-16.2 months) in group A and 7.3 months (95% CI: 4.3-10.3 months) in group B, respectively. The median progression-free survival (mPFS) was 5.7 months (95% CI: 4.1-7.2 months) and 5.0 months (95% CI: 3.1-6.9 months), respectively. The response rate (CR+PR) was 40% (16/40; 95% CI: 24.9-56.7%) in group A and 22.6% (7/31; 95% CI: 9.6-41.1%) in group B. Major grade 3 or 4 adverse events include neutropenia (41.3%), febrile neutropenia (9.3%), nausea/anorexia (10.7%), and vomiting (5.3%). There was no treatment-related death.

Conclusions

The combination chemotherapy with PCF is active and tolerable as first-line and second-line therapy in Chinese patients with advanced gastric and EGJ adenocarcinoma. The response and survival of PCF are same as those of DCF, but the tolerance is much better.

Colorectal cancer is one of the most common malignant tumors, and is associated with significant morbidity and mortality. In this study, recombinant analgesic-antitumor peptide (rAGAP), a protein consisting of small ubiquitin-related modifier (SUMO) linked with a hexa-histidine tag, was used as an antitumor analgesic peptide. The purpose of the present study was to investigate the antitumor activity of rAGAP in human colon adenocarcinoma SW480 cells and its potential molecular mechanisms of action. In this study, cell viability and apoptosis of rAGAP-treated SW480 cells was evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, flow cytometry and 4′,6-diamidino-2-phenylindole (DAPI) staining. Western blotting was used to investigate the effects of rAGAP on p27, Bcl-2/Bax and PTEN/PI3K/Akt cellular signal transduction. Our results showed that rAGAP not only enhanced apoptosis, but also inhibited the proliferation of SW480 cells. rAGAP upregulates the expression of p27 in SW480 cells and leads to cell cycle arrest in the G1 phase. Furthermore, rAGAP significantly increases the production of Bax and PTEN and suppresses the activation of Bcl-2, phosphatidylinositol 3-kinase (PI3K) and phospho-Akt (p-Akt) in SW480 cells. These results suggest that rAGAP may be a potential new anti-colorectal cancer drug.

AIM: To evaluate the efficacy and safety of transcatheter arterial chemoembolization (TACE) for gastrointestinal stromal tumor (GIST) with liver metastases after the failure of tyrosine kinase inhibitors (TKIs).

METHODS: Patients with histologically confirmed CD117-positive GIST with liver metastases who were resistant and/or intolerant to prior imatinib and/or sunitinib and who received TACE for at least one treatment cycle or only best supportive care and TKI reintroduction were eligible for the study. The patients were divided into two groups: those in TACE group received TACE treatment containing 5-20 mL iodized oil and 40-80 mg doxorubicin hydrochloride and TKI reintroduction or best supportive care, those in control group only received TKI reintroduction or best supportive care. The primary end-point was overall survival and the secondary end-points were, progression-free survival (PFS), response rates, and safety.

RESULTS: Sixty patients admitted between June 2008 and October 2011 were eligible for this study, including 22 in TACE group and 38 in control group. In the TACE group, 12 (54.5%) achieved liver partial response, 5 (22.7%) had stable disease, and 5 (22.7%) had liver progressive disease. Disease control rate of liver metastases was 77.3% in the TACE group and 39.5% in the control group. The median liver PFS in TACE group was 47.1 wk (95% CI: 23.9-70.3). The median PFS in TACE group was longer than in control group (30.0 wk, 95% CI: 20.1-39.9 vs 12.9 wk, 95% CI: 11.9-13.9) (P = 0.0001). The median overall survival in TACE group was also longer than in control group (68.5 wk, 95% CI: 57.4-79.6 vs 25.7 wk, 95% CI: 23.2-28.2) (P = 0.0001). TACE treatment significantly reduced the risk of death (hazard ratio: 0.109). Patients without extrahepatic metastases treated with TACE had significantly better prognosis. Most of the adverse events were of grade 1 or 2 and tolerable.

CONCLUSION: TACE is effective and well tolerated in GIST patients with liver metastases after TKI failure, and it may be an optional treatment for this disease.

Control of HIV-1 replication was first achieved with regimens that included a nonnucleoside reverse transcriptase inhibitor (NNRTI) or a protease inhibitor (PI); however, an explanation for the high antiviral activity of these drugs has been lacking. Indeed, conventional pharmacodynamic measures like IC50 (drug concentration causing 50% inhibition) do not differentiate NNRTIs and PIs from less active nucleoside reverse transcriptase inhibitors (NRTIs). Drug inhibitory potential depends on the slope of the dose-response curve (m), which represents how inhibition increases as a function of increasing drug concentration and is related to the Hill coefficient, a measure of intramolecular cooperativity in ligand binding to a multivalent receptor. Although NNRTIs and PIs bind univalent targets, they unexpectedly exhibit cooperative dose-response curves (m > 1). We show that this cooperative inhibition can be explained by a model in which infectivity requires participation of multiple copies of a drug target in an individual life cycle stage. A critical subset of these target molecules must be in the unbound state. Consistent with experimental observations, this model predicts m > 1 for NNRTIs and PIs and m = 1 in situations where a single drug target/virus mediates a step in the life cycle, as is the case with NRTIs and integrase strand transfer inhibitors. This model was tested experimentally by modulating the number of functional drug targets per virus, and dose-response curves for modulated virus populations fit model predictions. This model explains the high antiviral activity of two drug classes important for successful HIV-1 treatment and defines a characteristic of good targets for antiviral drugs in general, namely, intermolecular cooperativity.

Introduction

Rectal cancer with rectovesical fistula is a rare and difficult to treat entity. Here, we describe a case of rectal cancer with rectovesical fistula successfully managed by multimodality treatment. To the best of our knowledge, this is the first such case report in the literature.

Case presentation

A 51-year-old Chinese man was diagnosed as having rectal cancer accompanied by rectovesical fistula. He underwent treatment with neoadjuvant radiochemotherapy combined with total pelvic excision and adjuvant chemotherapy, as recommended by a multimodality treatment team. Post-operative pathology confirmed the achievement of pathological complete response.

Conclusions

This case suggests that a proactive multidisciplinary treatment is needed to achieve complete cure of locally advanced rectal cancer even in the presence of rectovesical fistula.

Highly active antiretroviral therapy (HAART)1–3 has dramatically decreased mortality from HIV-1 infection4 and is a major achievement of modern medicine. However, there is no fundamental theory of HAART. Elegant models describe the dynamics of viral replication3,5–9, but a metric for the antiviral activity of drug combinations relative to a target value needed for control of replication is lacking. Treatment guidelines10,11 are based on empirical results of clinical trials in which other factors like regimen tolerability also affect outcome. Why only certain drug combinations control viral replication remains unclear.

Here we quantify the intrinsic antiviral activity of antiretroviral drug combinations. We show that most single antiretrovirals exhibit previously unappreciated complex non-linear pharmacodynamics that determine their inhibitory potential at clinical concentrations. We demonstrate that neither of the major theories for drug combinations accurately predicts the combined effects of multiple antiretrovirals. However, combined effects can be understood with a novel approach that considers the degree of independence of drug effects.

This analysis allows a direct comparison of the inhibitory potential of different drug combinations under clinical concentrations, reconciles the results of clinical trials, defines a target level of inhibition associated with treatment success, and provides a rational basis for treatment simplification and optimization.

In the absence of a cure, most HIV-1-infected individuals will require life-long treatment. It is therefore essential to optimize highly active antiretroviral therapy. Recent research has shown that the slope parameter or Hill coefficient, which describes the steepness of a dose-response curve, is a critical missing dimension in the evaluation of antiviral drug activity. Based on this finding, the instantaneous inhibitory potential (IIP) has been derived as a new measure of antiviral drug activity. IIP incorporates the slope parameter and thus is a more accurate pharmacodynamic measure of antiviral activity than current measures such as IC50 and inhibitory quotient. However, it remains important to determine how to use IIP to predict the in vivo efficacy of anti-HIV-1 drugs. This article discusses recent advances in in vitro measures of antiviral activity and the therapeutic implications of the dose-response curve slope and IIP.

AIM: To investigate the efficacy and safety of imatinib dose escalation in Chinese patients with advanced gastrointestinal stromal tumor (GIST).

METHODS: Advanced GIST patients previously failing 400 mg imatinib treatment were enrolled in this study. Patients received imatinib with dose escalation to 600 mg/d, and further dose escalation to 800 mg/d if imatinib 600 mg/d failed. Progression-free survival, overall survival, clinical efficacy, c-kit/PDGFRA genotype and safety were evaluated.

RESULTS: 52 patients were enrolled in this study. For the 47 evaluable patients receiving imatinib (600 mg/d), the disease control rate was 40.4%, and the median progression-free survival for all patients was 17 wk (95% CI: 3.9-30.1). The median overall survival after dose escalation was 81 wk (95% CI: 36.2-125.8). Adverse events, mainly edema, fatigue, granulocytopenia and skin rash were tolerable. However, further dose escalation (800 mg/d) in 14 cases was ineffective, with disease progression and severe adverse events. Among 30 cases examined for gene mutations, patients with exon 9 mutations experienced a better progression-free survival of 47 wk.

CONCLUSION: Imatinib dose escalation to 600 mg/d is more appropriate for Chinese patients and may achieve further survival benefit.

Objective

To analyze the relationship between KRAS, BRAF mutations and the response toCetuximab in Chinese colorectal cancer patients.

Methods

A total of273 Chinese colorectal cancer patients were evaluated for KRAS and BRAF mutations by Sanger sequencing. Among them, 59 patients with metastatic colorectal cancer (mCRC) were treated with Cetuximab in combination with chemotherapy from August 2005 to July 2009. Statistical analysis was conducted to assess the relationship between KRAS, BRAF mutations and the response or survival of 59 mCRC patients.

Results

KRAS and BRAF mutation rates were 38.5% (105/273) and 5.1% (14/273), respectively, and KRAS/BRAF mutations were mutually exclusive. Among 59 patients treated with Cetuximab plus chemotherapy, KRAS and BRAF mutations were identified in 11and 5 patients, respectively. The response rates and median progression-free survivals (PFS) in KRAS wild-type and mutant patients were 35.4% (17/48) vs. 9.1% (1/11) (P=0.054) and 153 days vs. 99 days (P=0.01), respectively.Also, the response rates and median PFS in BRAF wild-type and mutant patients were 37.2% (16/43) vs. 20% (1/5) (P=0.016) and 138 days vs. 90 days (P=0.036), respectively.

Conclusion

Besides KRAS, assessing BRAF mutation should also be required to select patients eligible for Cetuximab. Further prospective evaluation in large samples should be performed to confirm these preliminary findings.

Objective

Toevaluate the role of class III β-tubulin (TUBB3), thymidylate synthase (TS), thymidine phosphorylase (TP), and excision repair cross-complementing group 1 (ERCC1) in clinical outcome of advanced gastric cancer patients receiving capecitabine plus paclitaxel or cisplatin.

Methods

The clinical data and tumor specimens from 57 advanced gastric cancer patients receiving first-line capecitabine plus paclitaxel (cohort 1, n=36) and capecitabine plus cisplatin (cohort 2, n=21) were retrospectively collected, and TUBB3, TS, TP, and ERCC1 expressions were detected by real-time quantitative PCR. The associations between expressions of biomarkers and response or survival were analyzed statistically.

Results

The median age of 57 patients was 57 years (range: 27–75 years) with 38 males and 19 females. Of all patients, the response rates of patients with high TP, low TP and high TS, low TS expressions were 57.1%, 27.6% (P=0.024), and 55.2%, 28.6% (P=0.042), respectively. Among cohort 1, the response rates and median overall survivals of patients with low and high TUBB3 expressions were 61.1% vs. 33.3% (P=0.095) and 13.8 months vs. 6.6 months (P=0.019), respectively; the response rate (87.5%) of patients with low TUBB3 and high TP expressions was higher than that (14.3%) of patients with high TUBB3 and low TP expressions (P=0.01). Among cohort 2, the response rates of patients with low ERCC1 and high ERCC1 expressions were 45.5% and 20.0% respectively (P=0.361).

Conclusion

TUBB3, TS and TP expressions could predict the response of advanced gastric cancer patients receiving capecitabine-based and paclitaxel-based chemotherapy. These results will be further confirmed in future large samples.

Acyclovir, a nucleoside analog, is thought to be specific for the human herpesviruses because it requires a virally encoded enzyme to phosphorylate it to acyclovir monophosphate. Recently, acyclovir triphosphate was shown to be a direct inhibitor of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase. Here, we showed that acyclovir is an inhibitor of HIV-1 replication in CD4+ T cells from cord blood that have undetectable levels of the eight human herpesviruses. Additionally, acyclovir phosphates were detected by reverse-phase-high performance liquid chromatography (RP-HPLC) and quantified in a primer extension assay from cord blood. The data support acyclovir as an inhibitor of HIV-1 replication in herpesvirus-negative cells.

Elite controllers or suppressors (ES) are a group of HIV-1-infected individuals who maintain viral loads below the limit of detection of commercial assays for many years. The mechanisms responsible for this remarkable control are under intense study, with the hope of developing therapeutic vaccines effective against HIV-1. In this study, we addressed the question of the intrinsic susceptibility of ES CD4+ T cells to infection. While we and others have previously shown that CD4+ T cells from ES can be infected by HIV-1 isolates in vitro, these studies were confounded by exogenous activation and in vitro culture of CD4+ T cells prior to infection. In order to avoid the changes in chemokine receptor expression that have been associated with such exogenous activation, we infected purified CD4+ T cells directly after isolation from the peripheral blood of ES, viremic patients, and uninfected donors. We utilized a green fluorescent protein (GFP)-expressing proviral construct pseudotyped with CCR5-tropic or CXCR4-tropic envelope to compare viral entry using a fluorescence resonance energy transfer-based, single-round virus-cell fusion assay. The frequency of productive infection was also compared by assessing GFP expression. CD4+ T cells from ES were as susceptible as or more susceptible than cells from viremic patients and uninfected donors to HIV-1 entry and productive infection. The results of this physiological study strongly suggest that differences in HIV-1 entry and infection of CD4+ T cells alone cannot explain the elite control of viral replication.

Background

To assess the role of Thymidine Phosphorylase and β-tubulin III in clinical outcome of Chinese advanced gastric cancer patients receiving first-line capecitabine plus paclitaxel.

Methods

The clinical data and tumor biopsies prior treatment from 33 advanced gastric cancer patients receiving capecitabine plus paclitaxel (cohort 1, experimental group) and 18 patients receiving capecitabine plus cisplatin (cohort 2, control group) in Beijing Cancer Hospital from July 2003 to December 2008 were retrospectively collected and analyzed for Thymidine Phosphorylase and β-tubulin III expressions by immunohistochemistry. The relationships between expressions of biomarkers and response or survival were determined by statistical analysis.

Results

The median age of 51 patients was 57 years (range, 27-75) with male 34 and female 17, and the response rate, median progression-free survival and overall survival were 43.1%, 120d and 265d. Among cohort 1, the response rate, median progression-free survival and overall survival in β-tubulin III positive (n = 22) and negative patients (n = 11) were 36.4%/72.7% (positive vs negative, P = 0.049), 86d/237d (P = 0.046) and 201d/388d (P = 0.029), respectively; the response rate (87.5% vs 14.3%, P = 0.01) and median progression-free survival (251d vs 84d, P = 0.003) in Thymidine Phosphorylase positive & β-tubulin III negative patients (n = 8) were also significantly higher than those in Thymidine Phosphorylase negative & β-tubulin III positive patients (n = 7). There was no correlation between β-tubulin III expression and response or survival among cohort 2 (n = 18).

Conclusions

In Chinese advanced gastric cancer, Thymidine Phosphorylase positive & β-tubulin III negative might predict response and prognosis to capecitabine plus paclitaxel chemotherapy. Further prospective evaluation in large samples should be performed to confirm these preliminary findings.

Summary

We show that entecavir, an FDA-approved drug used to treat chronic hepatitis B, potently inhibits HIV replication in vitro and leads to a 1 log decline in HIV RNA in vivo. Detailed analysis of two HIV-HBV co-infected patients receiving up to seven months of entecavir monotherapy demonstrated accumulation of HIV variants with the lamivudine-resistance mutation, M184V, in one of them. In vitro experiments demonstrated that M184V confers resistance to entecavir. Thus, entecavir has clinically relevant anti-HIV activity and can select for variants resistant to anti-HIV drugs. Until more is known about HIV resistance patterns and their selection by entecavir, caution is needed when using entecavir in HIV-HBV co-infected individuals not receiving fully suppressive antiretroviral regimens.

Background

This phase I, randomized, multicenter, open-label study investigated the pharmacokinetics, safety, and efficacy of the oral mammalian target of rapamycin inhibitor everolimus in Chinese patients with advanced solid tumors.

Methods

A total of 24 patients with advanced breast cancer (n = 6), gastric cancer (n = 6), non-small cell lung cancer (n = 6), or renal cell carcinoma (n = 6) who were refractory to/unsuitable for standard therapy were randomized 1:1 to oral everolimus 5 or 10 mg/day. Primary end points were pharmacokinetic parameters and safety and tolerability. Pharmacokinetic 24-h profiles were measured on day 15; trough level was measured on days 2, 8, 15, 16, and 22. Tolerability was assessed continuously. This final analysis was performed after all patients had received 6 months of study drug or had discontinued.

Results

Everolimus was absorbed rapidly; median Tmax was 3 h (range, 1-4) and 2 h (range, 0.9-6) in the 5 and 10 mg/day groups, respectively. Pharmacokinetic parameters increased dose proportionally from the 5 and 10 mg/day doses. Steady-state levels were achieved by day 8 or earlier. The most common adverse events suspected to be related to everolimus therapy were increased blood glucose (16.7% and 41.7%) and fatigue (16.7% and 33.3%) in the everolimus 5 and 10 mg/day dose cohorts, respectively. Best tumor response was stable disease in 10 (83%) and 6 (50%) patients in the 5 and 10 mg/day groups, respectively.

Conclusions

Everolimus 5 or 10 mg/day was well tolerated in Chinese patients with advanced solid tumors. The observed safety and pharmacokinetic profile of everolimus from this study were consistent with previous studies.

Trial registration

Chinese Health Authorities 2008L09346

Members of tripartite motif (TRIM) proteins in mammals play important roles in multiple cellular processes in the immune system. In the present study we have obtained the chicken TRIM39 with the insertion of a base A at position 1006 bp, compared to the sequence in the NCBI database (Accession No: NM 001006196), which made TRIM39 fulfill the TRIM rule of domain composition with both PRY, and SPRY domains. The open reading frame consisted of 1392 bp encoding 463 amino acid residues. The amino acid sequences of TRIM39 protein in mammals were highly similar (from 91.48% to 99.61%), while chicken TRIM39 had relatively low homology with mammals (from 29.2% to 39.59%). Real time RT-PCR indicated that the mRNA expression level of TRIM39 was the highest in spleen, with a lower expression in liver, brain, and lung, suggesting it might be an important protein participating in the immune system.

AIM: To investigate the prognostic value of KRAS mutation, and phosphatase and tensin (PTEN) expression in Chinese metastatic colorectal cancer metastatic colorectal cancer (mCRC) patients treated with cetuximab.

METHODS: Ninety Chinese mCRC patients treated with cetuximab were evaluated for KRAS mutation and PTEN protein expression by DNA sequencing of codons 12 and 13 and immunohistochemistry, respectively. We then selected 61 patients treated with cetuximab, either in combination with chemotherapy, or alone as a second-line or third-line regimen to assess whether KRAS mutation or PTEN protein expression is associated with the response and the survival time of mCRC patients treated with cetuximab.

RESULTS: KRAS mutation was found in 30 (33.3%) tumor samples from the 90 patients, and positive PTEN expression was detected in 58 (64.4%) of the 90 patients. Among the 61 patients who were treated with cetuximab as a second-line or third-line regimen, the resistance to cetuximab was found in 22 patients with KRAS mutation and in 39 patients without KRAS mutation, with a response rate of 4.5% and 46.1% respectively (P = 0.001), a shorter median progression-free survival (PFS) time of 14 ± 1.3 wk and 32 ± 2.5 wk respectively (P < 0.001), a median overall survival (OS) time of 11 ± 1.2 mo and 19 ± 1.8 mo respectively (P < 0.001), as well as in 24 patients with negative PTEN expression and in 37 patients with positive PTEN expression respectively (P < 0.001), with a responsive rate of 4.2% and 48.6% respectively, a shorter median PFS survival time of 17 ± 2.0 wk and 28 ± 1.9 wk respectively (P = 0.07), and a median OS time of 11 ± 1.3 mo and 18 ± 1.9 mo respectively (P = 0.004). Combined KRAS mutation and PTEN expression analysis showed that the PFS and OS time of patients with two favorable prognostic factors were longer than those of patients with one favorable prognostic factor or no favorable prognostic factor (P < 0.001).

CONCLUSION: KRAS mutation and PTEN protein expression are significantly correlated with the response rate and survival time of Chinese mCRC patients treated with cetuximab.

AIM: To compare the differences between dideoxy sequencing/KRAS StripAssay/pyrosequencing for detection of KRAS mutation in Chinese colorectal cancer (CRC) patients.

METHODS: Formalin-fixed, paraffin-embedded (FFPE) samples with tumor cells ≥ 50% were collected from 100 Chinese CRC patients at Beijing Cancer Hospital. After the extraction of genome DNA from FFPE samples, fragments contained codons 12 and 13 of KRAS exon 2 were amplified by polymerase chain reaction and analyzed by dideoxy sequencing, the KRAS StripAssay and pyrosequencing. In addition, the sensitivities of the 3 methods were compared on serial dilutions (contents of mutant DNA: 100%, 50%, 20%, 15%, 10%, 5%, 1%, 0%) of A549 cell line DNA (carrying the codon 12 Gly>Ser mutation) into wild-type DNA (human normal intestinal mucosa). The results of dideoxy sequencing, the KRAS StripAssay and pyrosequencing were analyzed by Chromas Software, Collector for KRAS StripAssay and the pyrosequencing PyroMarkTM Q24 system, respectively.

RESULTS: Among 100 patients, KRAS mutations were identified in 34%, 37% and 37% of patients by dideoxy sequencing, the KRAS StripAssay and pyrosequencing, respectively. The sensitivity was highest with the KRAS StripAssay (1%), followed by pyrosequencing (5%), and dideoxy sequencing was lowest (15%). Six different mutation types were found in this study with 3 main mutations Gly12Asp (GGT>GAT), Gly12Val (GGT>GTT) and Gly13Asp (GGC>GAC). Thirty-three patients were identified to have KRAS mutations by the 3 methods, and a total of 8 patients had conflicting results between 3 methods: 4 mutations not detected by dideoxy sequencing and the KRAS StripAssay were identified by pyrosequencing; 3 mutations not detected by dideoxy sequencing and pyrosequencing were identified by the KRAS StripAssay; and 1 mutation not detected by pyrosequencing was confirmed by dideoxy sequencing and the KRAS StripAssay. Among these discordant results, the results identified by dideoxy sequencing were consistent either with the KRAS StripAssay or with pyrosequencing, which indicated that the accuracy of dideoxy sequencing was high.

CONCLUSION: Taking a worldwide view of reports and our results, dideoxy sequencing remains the most popular method because of its low cost and high accuracy.

Summary

Purpose. This phase II, open-label, multicenter study assessed the oral, multitargeted, tyrosine kinase inhibitor sunitinib in patients with advanced gastric or gastroesophageal junction adenocarcinoma who had received prior chemotherapy. Experimental design. Patients received sunitinib 50 mg/day on Schedule 4/2 (4 weeks on treatment, followed by 2 weeks off treatment). The primary endpoint was objective response rate; secondary endpoints included clinical benefit rate, duration of response, progression-free survival (PFS), overall survival (OS), pharmacokinetics, pharmacodynamics, safety and tolerability, and quality of life. Results. Of 78 patients enrolled, most had gastric adenocarcinoma (93.6%) and metastatic disease (93.6%). All were evaluable for safety and efficacy. Two patients (2.6%) had partial responses and 25 patients (32.1%) had a best response of stable disease for ≥6 weeks. Median PFS was 2.3 months (95% confidence interval [CI], 1.6–2.6 months) and median OS was 6.8 months (95% CI, 4.4–9.6 months). Grade ≥3 thrombocytopenia and neutropenia were reported in 34.6% and 29.4% of patients, respectively, and the most common non-hematologic adverse events were fatigue, anorexia, nausea, diarrhea, and stomatitis. Pharmacokinetics of sunitinib and its active metabolite were consistent with previous reports. There were no marked associations between baseline soluble protein levels, or changes from baseline, and measures of clinical outcome. Conclusions. The progression-delaying effect and manageable toxicity observed with sunitinib in this study suggest that although single-agent sunitinib has insufficient clinical value as second-line treatment for advanced gastric cancer, its role in combination with chemotherapy merits further study.

Highly active antiretroviral therapy (HAART) can control HIV-1 replication1,2, but suboptimal treatment allows evolution of resistance and rebound viremia3–8. A comparative measure of antiviral activity under clinically relevant conditions would guide drug development and the selection of regimens that maximally suppress replication. Here we show that current measures of antiviral activity including IC50 and inhibitory quotient (IQ) neglect a critical dimension, dose-response curve slope. Using infectivity assays with wide dynamic range, we show that slope has dramatic effects on antiviral activity. Strikingly, slope values are class-specific for antiviral drugs and define intrinsic limitations on antiviral activity for some classes. Nucleoside reverse transcriptase inhibitors (NRTIs) and integrase inhibitors have slopes of ~1, characteristic of non-cooperative reactions, while nonnucleoside reverse transcriptase inhibitors (NNRTIs), protease inhibitors (PIs), and fusion inhibitors unexpectedly show slopes >1. Instantaneous inhibitory potential (IIP), the log reduction in single round infectivity at clinical drug concentrations, is strongly influenced by slope and varies by >8 logs for anti-HIV drugs. IIP provides a more accurate measure of antiviral activity and in general correlates with clinical outcomes. Only agents with slopes >1 achieve high level inhibition of single round infectivity, a finding with profound implications for drug and vaccine development.

CD4+ T-cell depletion is the hallmark of AIDS pathogenesis. Multiple mechanisms may contribute to the death of productively infected CD4+ T cells and innocent-bystander cells. In this study, we characterize a novel mechanism in which human immunodeficiency virus type 1 (HIV-1) infection preferentially depletes peripheral memory CD4+ T cells before the completion of reverse transcription. Using a recombinant HIV-1 carrying the green fluorescent protein reporter gene, we demonstrate that memory CD4+ T cells were susceptible to infection-induced cell death at a low multiplicity of infection. Infected memory CD4+ T cells underwent rapid necrotic cell death. Killing of host cells was dependent on X4 envelope-mediated viral fusion, but not on virion-associated Vpr or Nef. In contrast to peripheral resting CD4+ T cells, CD4+ T cells stimulated by mitogen or certain cytokines were resistant to HIV-1-induced early cell death. These results demonstrate that early steps in HIV-1 infection have a detrimental effect on certain subsets of CD4+ T cells. The early cell death may serve as a selective disadvantage for X4-tropic HIV-1 in acute infection but may play a role in accelerated disease progression, which is associated with the emergence of X4-tropic HIV-1 in the late stage of AIDS.

A paradox regarding the classic power spectral analysis of heart rate variability (HRV) is whether the characteristic high- (HF) and low-frequency (LF) spectral peaks represent stochastic or chaotic phenomena. Resolution of this fundamental issue is key to unraveling the mechanisms of HRV, which is critical to its proper use as a noninvasive marker for cardiac mortality risk assessment and stratification in congestive heart failure (CHF) and other cardiac dysfunctions. However, conventional techniques of nonlinear time series analysis generally lack sufficient sensitivity, specificity and robustness to discriminate chaos from random noise, much less quantify the chaos level. Here, we apply a ‘litmus test’ for heartbeat chaos based on a novel noise titration assay which affords a robust, specific, time-resolved and quantitative measure of the relative chaos level. Noise titration of running short-segment Holter tachograms from healthy subjects revealed circadian-dependent (or sleep/wake-dependent) heartbeat chaos that was linked to the HF component (respiratory sinus arrhythmia). The relative ‘HF chaos’ levels were similar in young and elderly subjects despite proportional age-related decreases in HF and LF power. In contrast, the near-regular heartbeat in CHF patients was primarily nonchaotic except punctuated by undetected ectopic beats and other abnormal beats, causing transient chaos. Such profound circadian-, age- and CHF-dependent changes in the chaotic and spectral characteristics of HRV were accompanied by little changes in approximate entropy, a measure of signal irregularity. The salient chaotic signatures of HRV in these subject groups reveal distinct autonomic, cardiac, respiratory and circadian/sleep-wake mechanisms that distinguish health and aging from CHF.

AIM: To evaluate the long-term risk of gastroduodenal ulcer and cardiovascular events induced by celecoxib in a population-based, randomized, double-blind, placebo-controlled study.

METHODS: From 2004 to 2006, a total of 1024 Chinese patients (aged 35 to 64 years) with severe chronic atrophic gastritis, intestinal metaplasia or dysplasia were randomly assigned to receive 200 mg of celecoxib twice daily or placebo in Linqu County (Shandong Province, China), a high-risk area of gastric cancer. All gastroduodenal ulcer and cardiovascular events occurred were recorded and the patients were followed up for 1.5 years after treatment. At the end of the trial, a systematic interview survey about other adverse events was conducted.

RESULTS: Gastroduodenal ulcer was detected in 19 of 463 (3.72%) patients who received celecoxib and 17 of 473 (3.31%) patients who received placebo, respectively (odds ratio = 1.13, 95% CI = 0.58-2.19). Cardiovascular (CV) events occurred in 4 patients who received celecoxib and in 5 patients who received placebo, respectively. Compared with those who received placebo, patients who received celecoxib had no significant increase in occurrence of CV events (hazard ratio = 0.84, 95% CI = 0.23-3.15). Among the adverse events acquired by interview survey, only the frequency of bloating was significantly higher in patients treated with celecoxib than in those treated with placebo.

CONCLUSION: Treatment of gastric cancer with celecoxib is not associated with increased risk of gastroduodenal ulcer and cardiovascular events.