Evaluation of antiproliferative and apoptotic effects of the rational combination of the MEK1/2 inhibitor selumetinib (AZD6244) and inhibitors of the hedgehog pathway in colorectal cancer (CRC) cell lines

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Background: The MAPK pathway is a crucial regulator of cell proliferation, survival, and resistance to apoptosis. Hyperactivation of this pathway due to mutations in KRAS have been reported in up to 50% of CRC cases. Clinical trials have shown that KRAS patients do not benefit from therapies targeting EGFR, highlighting the need for new therapeutic options. Utilizing differential gene array analyses, we have identified the hedgehog (HH) signaling pathway as a potential mediator of resistance to AZD6244. Based on these results, we tested the rational combination of selumetinib and the HH inhibitor, cyclopamine against human CRC cell lines.

Methods: CRC cell lines were exposed to varying concentrations of selumetinib and cyclopamine. For AZD6244, cell lines with IC50≤ 0.1 μM were considered extremely sensitive (ES) and those with IC50≥ 1μM were deemed extremely resistant (ER). Four KRAS mutant cell lines (2ES, 2ER) were selected for combination studies. The antiproliferative effects were assessed using the sulforhodamine B (SRB) cell viability assay, and potential synergy was evaluated using the Chou and Talalay method. Apoptosis was analyzed using bioluminescent caspase 3/7 detection.

Results: In all four cell lines tested, synergistic antiproliferative effects of selumetinib and cyclopamine were observed, including resistant lines to selumetinib. We observed significant induction of apoptosis when cell lines were exposed to the combination treatment, independent of their responsiveness to selumetinib in the SRB assay.

Conclusions: Treatment of KRAS mutant CRC cell lines with selumetinib and cyclopamine resulted in synergistic inhibition of proliferation, regardless of sensitivity to selumetinib. Interestingly, a significant increase in apoptosis was observed in response to the combination, which may explain the synergy observed by the combination index (CI). In vivo analyses of this combination in cell lines and human CRC explants are ongoing to further validate these results. These preclinical data may suggest a rational combination strategy for patients with KRAS mutant CRC.

No significant financial relationships to disclose.

[Validation of intensive medicine degree in the United Kingdom]

The specialty of Intensive Care Medicine was established over twenty years ago in Spain as part of the MIR (Resident training) system. The European Union allows for free circulation of its workers and the multilateral recognition of their university degrees as well as their postgraduate training. Unfortunately, our specialty is excluded from such a privilege. This limits our European rights and hinders the mobility of the intensivists trained in our country. The main objective of this article is to provide a practical guide on how to obtain recognition of the Spanish Certificate of Training (MIR system) in Intensive Care Medicine in the United Kingdom (UK). This review has been done by several Spanish intensivists with vast professional experience in the UK.

Meta-analysis of the colon J-pouch vs transverse coloplasty pouch after anterior resection for rectal cancer

PURPOSE

To evaluate the outcome of colonic J-pouches (CJP) and transverse colonic pouches (TCPs) after anterior resection for rectal cancer.

METHOD

Trials were located through Medline, Embase, the Cochrane Central Register of Controlled Trials, VIP and CNKI. Main end-points included functional outcomes, postoperative complications and anorectal physiological outcomes.

RESULTS

Of 120 articles, 34 compared CJP and TCP. Of these only six were randomized controlled trials (RCT), which fulfilled the inclusion criteria. These six included 648 patients, including 326 in the CJP group and 322 in the TCP group. There were no differences in the incidences of anastomotic leak [odds ratio 0.50, 95% confidence interval (CI) 0.21-1.18], chest infection (0.43, 0.09-2.00), wound infection (0.87, 0.33-2.30), anastomotic stricture (1.30, 0.44-3.84), fistula (0.64, 0.18-2.31).There were no difference in functional outcomes such as stool frequency [weighted mean difference (WMD) of -0.01, -0.30-0.27 at 6 months].There was no difference for anorectal physiology but heterogeneity existed: resting pressure (0.39, -1.76 to 2.55; 3.09, -0.04 to 6.23; 4.15, 2.21-6.094, at preoperation, 6 and 12 months,); squeeze pressure (-15.02, -46.14 to 16.10; -15.04, -37.04 to 6.97;0.83, -7.70 to 9.37 at preoperation, 6 and 12 months);(Neo)rectal threshold volume(8.49, 5.18-11.81; 27.13, -5.08 to 59.35, at preoperation and 6 months); Maximal (neo) rectal volume (-14.05, -36.60 to 8.50; 23.37, 2.65-44.09; -0.54, -0.91 to -0.18, at preoperation, 6 and at 12 months).

CONCLUSIONS

Transverse colonic pouch has similar results as CJP. As it is a safe, feasible, simple, technically easy and time-saving surgical procedure, TCP is a good candidate for wider clinical application.

Cetuximab-based therapy vs noncetuximab therapy in advanced or metastatic colorectal cancer: a meta-analysis of seven randomized controlled trials

PURPOSE

A meta-analysis was performed to assess the efficacy and safety of cetuximab-based therapy vs noncetuximab therapy in advanced or metastatic colorectal cancer.

METHOD

A total of 4617 patients from seven randomized controlled trials were available for analysis, with 2305 patients in the cetuximab group and 2312 patients in the noncetuximab group. The efficacy data included progression-free survival (PFS), overall survival (OS) and overall response rate (ORR). The safety data that contained overall grade 3 and 4 adverse events (AEs), specific grade 3 and 4 toxicity such as acneiform rash, cetuximab-related skin toxicity, diarrhoea, fatigue, neutropenia, hypertension, nausea and hand-foot skin reaction are evaluated.

RESULT

There was a significant PFS benefit in favour of cetuximab-based therapy (HR = 0.68, 95%CI: 0.63 to 0.73) and OS benefit (HR = 0.90, 95%CI: 0.81 to 1.00). The ORR was significantly higher in the cetuximab-based arm (OR = 2.19, 95% CI: 1.30 to 3.68). The incidence of overall grade 3-4 toxicity was significantly higher in the cetuximab arm compared with the noncetuximab arm (61.2%vs 43.0%, OR = 2.32, 95%CI: 1.59-3.39). This difference was mainly attributed to cetuximab-related skin toxicity (OR = 5.86, 95%CI: 1.38-24.88), especially acneiform rash (OR = 51.37, 95%CI: 22.75-116.02). In addition, cetuximab resulted in a significant increase in grade 3 and 4 diarrhoea, fatigue and neutropenia, except for hypertension, nausea and hand-foot skin reaction.

CONCLUSION

Cetuximab-based therapy improves PFS and OS resulting in better ORR vs noncetuximab therapy. Its most common and severe AE is skin toxicity that should be predictable and manageable.

Clinical responses observed with imatinib or sorafenib in melanoma patients expressing mutations in KIT

Background:

Mutations in KIT are more frequent in specific melanoma subtypes, and response to KIT inhibition is likely to depend on the identified mutation.

Methods:

A total of 32 patients with metastatic acral or mucosal melanoma were screened for mutations in KIT exons 11, 13 and 17.

Results:

KIT mutations were found in 38% of mucosal and in 6% of acral melanomas. Three patients were treated with imatinib and one with sorafenib. All four patients responded to treatment, but three have since progressed within the brain.

Conclusion:

The observed clinical responses support further investigation of KIT inhibitors in metastatic melanoma, selected according to KIT mutation status.

New genetic associations detected in a host response study to hepatitis B vaccine

The immune response to hepatitis B vaccination differs greatly among individuals, with 5-10% of healthy people failing to produce protective levels of antibodies. Several factors have been implicated in determining this response, chiefly individual genetic variation and age. Aiming to identify genes involved in the response to hepatitis B vaccination, a two-stage investigation of 6091 single-nucleotide polymorphisms (SNPs) in 914 immune genes was performed in an Indonesian cohort of 981 individuals showing normal levels of anti-HBs versus 665 individuals displaying undetectable levels of anti-HBs 18 months after initial dose of the vaccine. Of 275 SNPs identified in the first stage (476 normal/372 nonresponders) with P<0.05, significant associations were replicated for 25 polymorphisms in 15 genes (503 normal/295 nonresponders). We validated previous findings (HLA-DRA, rs5000563, P-value combined=5.57 x 10(-10); OR (95%CI)=0.61 (0.52-0.71)). In addition, we detected a new association outside of the human leukocyte antigen loci region that passed correction for multiple testing. This SNP is in the 3' downstream region of FOXP1, a transcription factor involved in B-cell development (P-value combined=9.2 x 10(-6); OR (95%CI)=1.38 (1.2-1.6)).These findings might help to understand the biological reasons behind vaccine failure and other aspects of variation in the immune responses of healthy individuals.

Ministry of health clinical practice guidelines: cancer screening

The Ministry of Health publishes national clinical practice guidelines to provide doctors and patients in Singapore with evidence-based guidance on managing important medical conditions. This article reproduces the introduction and executive summary (with key recommendations from the guidelines) from the Ministry of Health clinical practice guidelines on cancer screening, for the information of readers of the Singapore Medical Journal. Chapters and page numbers mentioned in the reproduced extract refer to the full text of the guidelines, which are available from the Ministry of Health website (http://www.moh.gov. sg/mohcorp/publications.aspx?id=24018). The recommendations should be used with reference to the full text of the guidelines. Following this article are multiple choice questions based on the full text of the guidelines.

Capecitabine plus oxaliplatin vs fluorouracil plus oxaliplatin as first line treatment for metastatic colorectal caner - meta-analysis of six randomized trials

OBJECTIVE

This meta-analysis was performed to evaluate the efficacy and safety of capecitabine plus oxaliplatin vs fluorouracil (FU) plus oxaliplatin as first line treatment for metastatic or advanced colorectal cancer.

METHOD

A total of 2196 patients from six randomized controlled trials were available for analysis, which included 1105 patients in capecitabine plus oxaliplatin group and 1091 patients in FU plus oxaliplatin group. The efficacy data included overall survival (OS), progression-free survival (PFS), time to treatment failure (TTF), overall response rate (ORR), and the safety data contained specific grade 3 and 4 toxicity such as anaemia, thrombocytopenia, neutropenia, diarrhoea, nausea, asthenia, vomiting, abdominal pain, hand foot syndrome, neuropathy and stomatitis were evaluated.

RESULTS

Pooled analysis of OS (hazards ratio HR = 1.04, 95%CI: 0.95-1.14), PFS (1.08, 0.98-1.18), ORR (odds ratio OR = 0.87, 0.73-1.03) in the capecitabine plus oxaliplatin group shows no statistical significance when compared with those in the FU plus oxaliplatin group. The statistically significant differences in pooled estimates suggest a higher incidence of grade 3/4 thrombocytopenia (OR = 1.87, 1.24-2.81), grade 3/4 hand-foot syndrome (3.90, 2.13-7.12) in the capecitabine plus oxaliplatin group and grade 3/4 neutropenia (0.20, 0.07-0.53) in the FU plus oxaliplatin group. No statistically significant difference was noted in the incidence of grade 3/4 anaemia, asthenia, diarrhoea, nausea, vomiting, abdominal pain, neuropathy and stomatitis.

CONCLUSION

The effect of capecitabine plus oxaliplatin regimen is similar to FU plus oxaliplatin regimen as first line treatment for metastatic colorectal cancer, but it offers advantages of simplicity and convenience to administer.

Physical Activity Levels of Women Attending Glasgow Breast Clinics

IntroductionEpidemiological studies suggest that moderate intensity recreational physical activity (PA) improves breast cancer survival. We aimed to assess the current levels of PA in breast cancer survivors and a cohort of women with benign disease attending clinics in Glasgow.Materials and MethodsPatients at breast clinics at the GRI and WIG were recruited over a 5 week period. Data on physical activity levels (occupational, household, recreational) over the 7 days were recorded using the International Physical Activity Questionaire (IPAQ).ResultsA total of 352 patients were recruited with 141 (40.1%) of the patients completing the questionnaire successfully (table 1).Table 1  Women attending symptomatic clinicBreast cancer survivorsNo. patients 9742Median Age 4263Average physical activity levels (MET-Hr / Week)Total11493.4 Physical19.619.7 Household35.740.0 Occupational40.523.9 Recreational PA appears to be the major influence on breast cancer survival (1) and the reported MET-hr/week for each cohort are shown in table 2.Table 2Recreational Physical activity levels (MET-Hr / Week)Women attending symptomatic clinicBreast cancer survivors&lt;533 (34%)21 (50%)5 - 1014 (14%)5 (12%)10 - 1918 (19%)8 (19%)&gt;1932 (33%)8 (19%) DiscussionScottish guidelines (2) suggest 30min of moderate exercise most days a week is beneficial (&gt;10MET-hr/week) but over 60% of our patients were not achieving this. A recreational PA level of &gt;5MET/hr/week has been demonstrated to confer a benefit on breast survival (1). However 50% of our breast cancer survivors are not meeting this relatively modest target (equivalent to 1hr15min moderate activity/week). With the planned implementation of an exercise programme for all newly diagnosed breast cancer patients in Glasgow, we hope to improve levels of recreational physical activity and will re-audit following its introduction.References1. Friedenreich CM, Gregory J, Prospective cohort study of lifetime physical activity and breast cancer survival. Int J Cancer. 2009 Apr 15;124(8):1954-622. Let's Make Scotland more active: A strategy for physical activity. Physical activity task force http://www.scotland.gov.uk/Publications/2003/02/16324/17895 [Online March 2009]

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2066.

Gastrointestinal and Cardiovascular Safety Profiles of Neratinib Monotherapy in Patients with Advanced ErbB2-Positive Breast Cancer

Background: In a phase 2 study, oral neratinib was administered to patients (pts) with advanced breast cancer in 2 cohorts, those with prior trastuzumab treatment (prior T, n=66) and those with no prior trastuzumab treatment (no prior T, n=70). Neratinib demonstrated robust antitumor activity with objective response rates of 26% and 51%, respectively, and was generally tolerable (Burstein et al. Cancer Res 2009;69:72S). Diarrhea, all grades, occurred in 89% of total pts. Characteristics of the diarrhea and left ventricular ejection fraction (LVEF) measurements are described. Methods: Pts were required to have ErbB2 gene amplification in tumor tissue as measured by fluorescence in situ hybridization by independent assessment. Serial LVEF measurements were made with a multigated acquisition scan or echocardiogram. Pts were ineligible if baseline LVEF was &lt;50%. Adverse events were graded based on the NCI Common Terminology Criteria, v 3.0. Pts received oral neratinib 240 mg daily. Results: Data collected by 18 Mar 2009 are reported; the median (range) duration of neratinib treatment was 4.5 (0.2-23.5) months for pts with prior T and 7.8 (0.5-24.2) months for pts with no prior T. Diarrhea, all grades occurred in 93% of the total population (prior T: 97%, no prior T: 89%); grade 3-4 diarrhea occurred in 21% of the total population (prior T: 30%, no prior T: 13%). Median times of onset were 2 and 3 days after first dose of neratinib, respectively, and median durations of diarrhea were 7 and 5 days. In study week 1, 86% and 73% of pts with prior T and no prior T, respectively, had diarrhea; this decreased to 12-14% in months 3 and 4 (Table). Diarrhea was the cause of dose interruptions in 36% of pts with prior T and 11% of pts with no prior T and of dose reductions in 30% of pts with prior T and 5% of pts with no prior T; only 1 pt (prior T) discontinued treatment due to diarrhea. Pts used anti-diarrheal medications for supportive therapy (prior T: 91%, no prior T: 67%). For LVEF measurements, there was little variation from baseline in most pts during the study. Four pts had at least 1 LVEF measurement &lt;50% (2 of these pts had measurements within the institutional range of normal). None had congestive heart failure. One of these pts had grade 3 atrioventricular block and grade 3 bradycardia, which were considered unrelated to neratinib. Discussion: Neratinib treatment was not associated with clinically significant cardiotoxicity. Pts who developed diarrhea with neratinib monotherapy had early onset, but frequency and severity decreased with time on study. Despite the high frequency of diarrhea with neratinib treatment, it was readily managed with supportive therapy and dose interruptions and/or reductions.Time Course of Diarrhea in ErbB2-Positive Breast Cancer Patients Treated With NeratinibStudy PeriodPrior T: No. on StudyPrior T: % With Diarrhea, All Grades*Prior T: % With Diarrhea, Gr 3-4*No Prior T: No. on StudyNo Prior T: % With Diarrhea, All Grades*No Prior T: % With Diarrhea, Gr 3-4*Week 166861770737Week 2-466611170436Month 260331066152Month 34713060120Month 44312058140*For pts with multiple toxicity grades in a period, the maximum grade was reported.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5096.

The effect of aspirin in the recurrence of colorectal adenomas: a meta-analysis of randomized controlled trials

PURPOSE

Colorectal adenomas are precursors of most colorectal cancers and are important targets for chemoprevention. Aspirin is thought to play an important role in chemoprevention. However, the role of aspirin in preventing recurrence of adenomas is controversial. We performed a systematic review and meta-analysis to evaluate the effect of aspirin in preventing the recurrence of colorectal adenoma.

METHOD

Trials were located through Medline, Embase and the Cochrane Central Register of Controlled Trials (CENTRAL). From 14 articles screened, three were identified as randomized controlled trials and were included for data extraction. Main outcome measures were the recurrence of any new adenoma and advanced adenoma. The meta-analysis was performed with the fixed-effects model.

RESULTS

A total of 2338 participants were enrolled in the three studies and 2175 of them completed the follow-up colonoscopy. We found that the relative risks of any adenoma (when compared with the placebo group) were 0.859 in the high dose of aspirin groups (95% confidence interval (CI), 0.756-0.976, P = 0.019), 0.826 in the low dose of aspirin groups (95% CI 0.706-0.965, P = 0.016) and 0.836 in the both aspirin combined groups (95% CI 0.746-0.937, P = 0.002). For the recurrence of advanced adenoma, the relative risk (when compared with the placebo group) was 0.655 (95% CI 0.513-0.837, P = 0.001) in the aspirin groups without considering the dose.

CONCLUSION

This meta-analysis suggests that aspirin prevents recurrent colorectal adenomas among patients with a history of colorectal adenomas.

Meta-analysis of endoscopic submucosal dissection versus endoscopic mucosal resection for tumors of the gastrointestinal tract

BACKGROUND AND STUDY AIMS

Endoscopic submucosal dissection (ESD) has been developed to overcome the limitations of endoscopic mucosal resection (EMR). We aimed to compare the outcomes of these two methods.

METHODS

Databases, including Pubmed, EMBASE, and The Cochrane Library, were searched to identify studies comparing ESD with EMR for premalignant and malignant lesions of the gastrointestinal tract. In a meta-analysis, primary end points were the en bloc resection rate and the curative resection rate; secondary end points were operation time, and rates of bleeding, perforation, and local recurrence.

RESULTS

15 nonrandomized studies (seven full-text and eight abstracts) were identified. Meta-analysis showed higher en bloc and curative resection rates (odds ratio [OR] 13.87, 95 %CI 10.12 - 18.99; OR 3.53, 95 %CI 2.57 - 4.84) irrespective of lesion size. Subgroup analysis showed higher en bloc and curative resection rates with ESD for esophageal, gastric, and colorectal neoplasms, and for lesions of size < 10 mm, 10 mm < 20 mm, and > 20 mm. Local recurrence was lower with ESD (OR 0.09, 95 %CI 0.04 - 0.18). But ESD was more time-consuming than EMR (weighted mean difference [WMD] 1.76; 95 %CI 0.60 - 2.92), and showed high procedure-related bleeding and perforation rates (OR 2.20, 95 %CI 1.58 - 3.07; OR 4.09, 95 %CI 2.47 - 6.80).

CONCLUSIONS

ESD showed better en bloc and curative resection rates and local recurrence compared with EMR, but was more time-consuming and had higher rates of bleeding and perforation complications. These results need to be confirmed by high quality trials and further studies in the west.

Transgenic silencing of neurons in the mammalian brain by expression of the allatostatin receptor (AlstR)

The mammalian brain is an enormously complex set of circuits composed of interconnected neuronal cell types. The analysis of central neural circuits will be greatly served by the ability to turn off specific neuronal cell types while recording from others in intact brains. Because drug delivery cannot be restricted to specific cell types, this can only be achieved by putting "silencer" transgenes under the control of neuron-specific promoters. Towards this end we have created a line of transgenic mice putting the Drosophila allatostatin (AL) neuropeptide receptor (AlstR) under the control of the tetO element, thus enabling its inducible expression when crossed to tet-transactivator lines. Mammals have no endogenous AL or AlstR, but activation of exogenously expressed AlstR in mammalian neurons leads to membrane hyperpolarization via endogenous G-protein-coupled inward rectifier K(+) channels, making the neurons much less likely to fire action potentials. Here we show that this tetO/AlstR line is capable of broadly expressing AlstR mRNA in principal neurons throughout the forebrain when crossed to a commercially-available transactivator line. We electrophysiologically characterize this cross in hippocampal slices, demonstrating that bath application of AL leads to hyperpolarization of CA1 pyramidal neurons, making them refractory to the induction of action potentials by injected current. Finally, we demonstrate the ability of AL application to silence the sound-evoked spiking responses of auditory cortical neurons in intact brains of AlstR/tetO transgenic mice. When crossed to other transactivator lines expressing in defined neuronal cell types, this AlstR/tetO line should prove a very useful tool for the analysis of intact central neural circuits.

Rationally designed treatment for solid tumors with MAPK pathway activation

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Background: Preclinical studies shed light to the mechanism conferring paclitaxel resistance in solid tumors with active Ras/Raf/Mitogen-Activated Protein Kinase (MAPK) pathway, and determined a molecular mechanism by which addition of the proteasome inhibitor bortezomib abrogated this resistance, enabling tumor regression in animals in vivo. Methods: A Phase I study was contacted to determine the MTD of paclitaxel and bortezomib combinatorial treatment. Sixteen patients with refractory solid tumors were treated with weekly paclitaxel and bortezomib. Six patients had NSCLC; 4, colon cancer; 2, pancreatic; 2, melanoma; 1, breast; 1, ovarian. Patients with baseline neuropathy greater than or equal to Grade 1 were excluded. The starting dose was 40 mg/m2 for paclitaxel and 0.7 mg/m2 for bortezomib. A modified continual reassessment method (MCRM) was used for dose escalation with 3-patient cohorts treated at each dose level. The Target Toxicity Level (probability of DLT at the MTD) was set at 25%. Maximum dose escalation was no more than 75% of the previous SED level, if no Grade 3 hematologic toxicity or DLT were observed. Otherwise, the maximum dose escalation was no more than 50% of the previous SED level. The process continued until SED changes were no more than 10% for two consecutive cohorts. Results: The MTD for the combinatorial treatment was reached at 60 mg/m2 paclitaxel and 1.0 mg/m2 bortezomib. Of 15 evaluable patients, 1 patient with paclitaxel-resistant NSCLC had PR and 5 patients (2, NSCLC; 1, pancreatic; 1, colon; 1, ovarian) had stable disease. Median TTP was 2.3 months (0.8 to 6 months). Three NSCLC patients achieved TTP longer than 5 months. The combination of paclitaxel and bortezomib was relatively well tolerated. Paclitaxel PK parameters are being determined, and paraffin-embedded tumor specimens are being evaluated for MAPK pathway activation by IHC for phospho-ERK. Results will be correlated with clinical response. Conclusions: The MTD for the proposed combinatorial treatment is 60 mg/m2 for paclitaxel and 1.0 mg/m2 for bortezomib, and is relatively well tolerated. Combination of paclitaxel with bortezomib is effective in taxane-resistant NSCLC, and worthy of further investigation.

No significant financial relationships to disclose.

Use of amolecular mimicry approach to identify effective agents in pancreatic cancer

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Background: We proposed a molecular mimicry approach (prêt-à-porter), based on pathway-expression signatures that systematically connect a query case with the most similar profile from a reference profile database and extrapolates the most effective drug for personalized medicine. Here we report the pre-clinical and clinical validation of this concept in pancreatic cancer treatment. Methods: Baseline gene expression profiles of 24 patients that received gemcitabine as adjuvant chemotherapy were collected. A patient is defined as sensitive and resistant to gemcitabine if the disease free survival (DFS) is more and less than 300 days, respectively. We also performed a small scale pre-clinical study on comparing patient-derived xenografts refractory to gemcitabine in a second-line treatment of prêt-à-porter choice of drugs vs. one-size-fits-all choice of drug (erlotinib). Four gemcitabine resistant xenografts were randomly assigned into control, erlotinib and the prêt-à-porter choice of drug groups. Tumor growth inhibition values (TGI) were calculated at the end of the experiment. Results: Using the molecular mimcry concept, where a patient is connected to a sensitive cell line, s/he will be predicted as sensitive to gemcitabine and vice versa. The prêt-à-porter achieved an overall prediction accuracy of 71% on these retrospective patient samples. Our approach correctly classified 67% and 75% of the patients that were sensitive and resistant to gemcitabine as adjuvant chemotherapy, respectively. The median DFS for the sensitive and resistant groups are 491 and 162 days, respectively. This difference was statistically significant (log-rank test, p = 0.04). Furthermore, the mean TGI% for the prêt-à-porter is about 10-fold lower than the erlotinib arm (3% vs. 30%, Chi-square test, p = 0.02) in the pre-clinical study. This demonstrates that prêt-à-porter approach can be used to tailor personalized medicine and achieved better clinical response as compared to the current treatment approach. Conclusions: We comprehensively validated the prêt-à-porter approach in pre-clinical and clinical data and demonstrated that this approach can be used as a powerful translation research tool in enriching patient selection of novel drugs in clinical trials and realizing personalized medicine.

[Table: see text]

Preclinical identification of biomarkers of response to mTOR inhibitors and subsequent application in a phase II trial of sirolimus in pancreatic cancer patients refractory to gemcitabine

4612

Background: Treatment for advanced pancreatic cancer refractory to gemcitabine has not been defined. We conducted an efficacy study in pancreatic cancer xenografts to identify biomarkers of response to mTOR inhibition and attempted to translate the results by conducting a phase II trial of sirolimus in this patient population. Methods: 19 direct pancreatic xenografts were treated with temsirolimus (20mg/Kg IP daily) for 28 days. Tumors were profiled with array CGH and gene expression arrays at baseline. TGI were calculated at 28 days. Patients refractory to gemcitabine were included in the clinical trial. Sirolimus was administered at 5mg/day for 28 days. Primary endpoint was 6 month survival rate (6mSR). Secondary endpoints included: baseline evaluation of AKT pathway activation, pharmacodynamic assessment of p-S6K in PBMC, pharmacokinetics and toxicity analysis. Results: In the preclinical study, mTOR sensitive tumors showed upregulation of genes involved in the renal cell cancer pathway. CGH identified focal gains in N-Ras and K-Ras and homozygous deletions of FHIT in sensitive cases. Overall, these genetic changes induced AKT pathway activation, and led us to explore high baseline p-S6K expression as a predictor of outcome in the clinical phase. Patient characteristics: Median age: 64 (39–77). 11 patients had received ≥ 2 prior lines of chemotherapy. 6mSR was 20%. 6mSR in the subgroup of patients who received rapamycin as first line chemotherapy after progression to gemcitabine was 34%. Baseline tumor p-S6K was not predictive for survival. Early pharmacodynamic changes in p-S6K in PBMC 6 hours after treatment initiation were correlated with survival (R2= 0.65). Treatment was well tolerated. The most common grade 3 adverse event was hyperglycemia in 10% of the patients. 7 (23%) patients achieved stable disease. Conclusions: Rapamycin is well tolerated in this setting. Early pharmacodynamic changes in p-S6K in PBMC were correlated with survival. Preclinical findings leading to activation of the AKT pathway in all sensitive cases warrants further validation studies. Efficacy data is limited by the selection of a heavily pretreated and poor prognosis population (DFS≤47 days).

No significant financial relationships to disclose.

Efficacy comparison between intraportal and subcapsular islet transplants in a murine diabetic model

BACKGROUND

It is important to determine the efficacy of intraportal (IP) islet transplantation in comparison with other transplant sites. In this study, we sought to determine the optimal number of islets to achieve normoglycemia following transplantation into the liver versus the kidney using a mouse model.

METHODS

Streptozotocin-induced diabetic mice (Balb/C) were transplanted with syngeneic islets via the IP versus renal subcapsular (SC) routes. The transplanted islet numbers were 0 to 800 (n = 3-5). We assessed the correlation between parameters and islet numbers, comparing IP versus SC groups. The parameters were: (1) percentage of normoglycemia; (2) postoperative days to normoglycemia; (3) mean blood glucose levels at various points from pretransplantation to the end of the study (postoperative day 28); (4) mean serum insulin; and (5) area under the curve of blood glucose levels after glucose injection.

RESULTS

Two hundred islets yielded normoglycemia in renal subcapsular grafts, while 800 islets were the minimum required for normoglycemia with IP transplantation. The transplant efficacy in SC transplantation was 2 to 5 times greater than that of IP transplantation. The days to normoglycemia were significantly different between IP versus renal SC islets (13.25 +/- 4.38 days vs 4.50 +/- 0.81 days; P = .007).

CONCLUSION

The efficacy of islet transplantation in murine diabetic models was significantly greater under the kidney capsule. Clinical islet transplantation could benefit from trials of alternative transplant sites.