Intratumoral nanoplexed poly I:C BO-112 in combination with systemic anti-PD-1 for patients with anti-PD-1-refractory tumors

Intratumoral therapies, especially Toll-like receptor agonists, can trigger both the innate and adaptive immune systems. BO-112 is a nanoplexed form of polyinosinic:polycytidylic acid (poly I:C) that induces local and systemic immunotherapeutic effects in mouse models. In a multicenter phase 1 clinical trial, repeated intratumoral administrations of BO-112 induced an increase in tumor cell necrosis and apoptosis, as well as augmented immune reactivity according to gene expression profiling. The first three cohorts receiving BO-112 as a monotherapy resulted in a recommended dose of 1 mg that could be safely repeated. Two grade 3 to 4 adverse reactions in the form of reversible thrombocytopenia were reported. In a fourth cohort of 28 patients with tumors that had primary resistance to anti-programmed cell death protein-1 (PD-1), the combination of intratumoral BO-112 with nivolumab or pembrolizumab was also well tolerated, and 3 patients (2 with melanoma and 1 with renal cell carcinoma) achieved partial responses, with 10 more patients having stable disease at 8 to 12 weeks. Thus, local BO-112 combined with a systemic anti-PD-1 agent might be a strategy to revert anti-PD-1 resistance.

Updated Analysis From KEYNOTE-189: Pembrolizumab or Placebo Plus Pemetrexed and Platinum for Previously Untreated Metastatic Nonsquamous Non–Small-Cell Lung Cancer

PURPOSE

In KEYNOTE-189, first-line pembrolizumab plus pemetrexed-platinum significantly improved overall survival (OS) and progression-free survival (PFS) compared with placebo plus pemetrexed-platinum in patients with metastatic nonsquamous non‒small-cell lung cancer (NSCLC), irrespective of tumor programmed death-ligand 1 (PD-L1) expression. We report an updated analysis from KEYNOTE-189 (ClinicalTrials.gov: NCT02578680 ).

METHODS

Patients were randomly assigned (2:1) to receive pemetrexed and platinum plus pembrolizumab (n = 410) or placebo (n = 206) every 3 weeks for 4 cycles, then pemetrexed maintenance plus pembrolizumab or placebo for up to a total of 35 cycles. Eligible patients with disease progression in the placebo-combination group could cross over to pembrolizumab monotherapy. Response was assessed per RECIST (version 1.1) by central review. No alpha was assigned to this updated analysis.

RESULTS

As of September 21, 2018 (median follow-up, 23.1 months), the updated median (95% CI) OS was 22.0 (19.5 to 25.2) months in the pembrolizumab-combination group versus 10.7 (8.7 to 13.6) months in the placebo-combination group (hazard ratio [HR], 0.56; 95% CI, 0.45 to 0.70]). Median (95% CI) PFS was 9.0 (8.1 to 9.9) months and 4.9 (4.7 to 5.5) months, respectively (HR, 0.48; 95% CI, 0.40 to 0.58). Median (95% CI) time from randomization to objective tumor progression on next-line treatment or death from any cause, whichever occurred first (progression-free-survival-2; PFS-2) was 17.0 (15.1 to 19.4) months and 9.0 (7.6 to 10.4) months, respectively (HR, 0.49; 95% CI, 0.40 to 0.59). OS and PFS benefits with pembrolizumab were observed regardless of PD-L1 expression or presence of liver/brain metastases. Incidence of grade 3-5 adverse events was similar in the pembrolizumab-combination (71.9%) and placebo-combination (66.8%) groups.

CONCLUSION

First-line pembrolizumab plus pemetrexed-platinum continued to demonstrate substantially improved OS and PFS in metastatic nonsquamous NSCLC, regardless of PD-L1 expression or liver/brain metastases, with manageable safety and tolerability.

Management of oligometastatic non-small cell lung cancer patients: Current controversies and future directions

Oligometastatic non-small cell lung cancer (NSCLC) describes an intermediate stage of NSCLC between localized and widely-disseminated disease. This stage of NSCLC is characterized by a limited number of metastases and a more indolent tumor biology. Currently, the management of oligometastatic NSCLC involves radical treatment (radiotherapy or surgery) that targets the metastatic lesions and the primary tumor to achieve disease control. This approach offers the potential to achieve prolonged survival in patients who, in the past, would have only received palliative measures. The optimal therapeutic strategies for the different scenarios of oligometastatic disease (intracranial vs extracranial disease, synchronous vs metachronous) remain undefined. Given the lack of head-to-head studies comparing radiotherapy to surgery in these patients, the decision to apply surgery or radiotherapy (with or without systemic treatment) must be based on prognostic factors that allow us to classify patients. This classification will allow us to select the most appropriate therapeutic strategy on an individualized basis. In the future, the molecular or microRNA profiles will likely improve the treatment selection process. The objective of the present article is to review the most relevant scientific evidence on the management of patients with oligometastatic NSCLC, focusing on the role of radiotherapy and surgery. We also discuss areas of controversy and future directions.

Pembrolizumab plus Chemotherapy in Metastatic Non-Small-Cell Lung Cancer

BACKGROUND

First-line therapy for advanced non-small-cell lung cancer (NSCLC) that lacks targetable mutations is platinum-based chemotherapy. Among patients with a tumor proportion score for programmed death ligand 1 (PD-L1) of 50% or greater, pembrolizumab has replaced cytotoxic chemotherapy as the first-line treatment of choice. The addition of pembrolizumab to chemotherapy resulted in significantly higher rates of response and longer progression-free survival than chemotherapy alone in a phase 2 trial.

METHODS

In this double-blind, phase 3 trial, we randomly assigned (in a 2:1 ratio) 616 patients with metastatic nonsquamous NSCLC without sensitizing EGFR or ALK mutations who had received no previous treatment for metastatic disease to receive pemetrexed and a platinum-based drug plus either 200 mg of pembrolizumab or placebo every 3 weeks for 4 cycles, followed by pembrolizumab or placebo for up to a total of 35 cycles plus pemetrexed maintenance therapy. Crossover to pembrolizumab monotherapy was permitted among the patients in the placebo-combination group who had verified disease progression. The primary end points were overall survival and progression-free survival, as assessed by blinded, independent central radiologic review.

RESULTS

After a median follow-up of 10.5 months, the estimated rate of overall survival at 12 months was 69.2% (95% confidence interval [CI], 64.1 to 73.8) in the pembrolizumab-combination group versus 49.4% (95% CI, 42.1 to 56.2) in the placebo-combination group (hazard ratio for death, 0.49; 95% CI, 0.38 to 0.64; P<0.001). Improvement in overall survival was seen across all PD-L1 categories that were evaluated. Median progression-free survival was 8.8 months (95% CI, 7.6 to 9.2) in the pembrolizumab-combination group and 4.9 months (95% CI, 4.7 to 5.5) in the placebo-combination group (hazard ratio for disease progression or death, 0.52; 95% CI, 0.43 to 0.64; P<0.001). Adverse events of grade 3 or higher occurred in 67.2% of the patients in the pembrolizumab-combination group and in 65.8% of those in the placebo-combination group.

CONCLUSIONS

In patients with previously untreated metastatic nonsquamous NSCLC without EGFR or ALK mutations, the addition of pembrolizumab to standard chemotherapy of pemetrexed and a platinum-based drug resulted in significantly longer overall survival and progression-free survival than chemotherapy alone. (Funded by Merck; KEYNOTE-189 ClinicalTrials.gov number, NCT02578680 .).

PROCLAIM: Randomized Phase III Trial of Pemetrexed-Cisplatin or Etoposide-Cisplatin Plus Thoracic Radiation Therapy Followed by Consolidation Chemotherapy in Locally Advanced Nonsquamous Non-Small-Cell Lung Cancer

PURPOSE

The phase III PROCLAIM study evaluated overall survival (OS) of concurrent pemetrexed-cisplatin and thoracic radiation therapy (TRT) followed by consolidation pemetrexed, versus etoposide-cisplatin and TRT followed by nonpemetrexed doublet consolidation therapy.

PATIENTS AND METHODS

Patients with stage IIIA/B unresectable nonsquamous non-small-cell lung cancer randomly received (1:1) pemetrexed 500 mg/m(2) and cisplatin 75 mg/m(2) intravenously every 3 weeks for three cycles plus concurrent TRT (60 to 66 Gy) followed by pemetrexed consolidation every 3 weeks for four cycles (arm A), or standard therapy with etoposide 50 mg/m(2) and cisplatin 50 mg/m(2) intravenously, every 4 weeks for two cycles plus concurrent TRT (60 to 66 Gy) followed by two cycles of consolidation platinum-based doublet chemotherapy (arm B). The primary objective was OS. The study was designed as a superiority trial with 80% power to detect an OS hazard ratio of 0.74 with a type 1 error of .05.

RESULTS

Enrollment was stopped early because of futility. Five hundred ninety-eight patients were randomly assigned (301 to arm A, 297 to arm B) and 555 patients (283 in arm A, 272 in arm B) were treated. Arm A was not superior to arm B in terms of OS (hazard ratio, 0.98; 95% CI, 0.79 to 1.20; median, 26.8 v 25.0 months; P = .831). Arm A had a significantly lower incidence of any drug-related grade 3 to 4 adverse events (64.0% v 76.8%; P = .001), including neutropenia (24.4% v 44.5%; P < .001), during the overall treatment period.

CONCLUSION

Pemetrexed-cisplatin combined with TRT followed by consolidation pemetrexed was not superior to standard chemoradiotherapy for stage III unresectable nonsquamous non-small-cell lung cancer.

Primary human non-small cell lung and pancreatic tumorgraft models--utility and applications in drug discovery and tumor biology

The number of therapeutic options for lung and pancreatic cancer is increasing because of the identification of new druggable molecular targets and development of new drug combinations. Reproducible, biologically relevant in vivo pre-clinical models are critical for this effort. The generation of patient-derived tumor xenografts has proven useful for integrating drug screening with biomarker discovery, discovering fundamental information in tumor biology, prioritizing drugs for clinical investigation, and personalizing treatments for these tumors. The protocol described in this unit details how to establish a direct in vivo subcutaneous primary tumorgraft and maintenance passages. The predictive value of a tumorgraft platform to guide personalized medicine is illustrated with the case of a patient with refractory advanced non-small cell lung cancer (NSCLC). The outcome of a patient for whom their own pancreatic tumorgraft revealed a remarkable sensitivity to mitomycin C based on a PALB2 mutation is also detailed.

A comparison of EGFR mutation testing methods in lung carcinoma: direct sequencing, real-time PCR and immunohistochemistry

The objective of this study is to compare two EGFR testing methodologies (a commercial real-time PCR kit and a specific EGFR mutant immunohistochemistry), with direct sequencing and to investigate the limit of detection (LOD) of both PCR-based methods. We identified EGFR mutations in 21 (16%) of the 136 tumours analyzed by direct sequencing. Interestingly, the Therascreen EGFR Mutation Test kit was able to characterize as wild-type one tumour that could not be analyzed by direct sequencing of the PCR product. We then compared the LOD of the kit and that of direct sequencing using the available mutant tumours. The kit was able to detect the presence of a mutation in a 1% dilution of the total DNA in nine of the 18 tumours (50%), which tested positive with the real-time quantitative PCR method. In all cases, EGFR mutation was identified at a dilution of 5%. Where the mutant DNA represented 30% of the total DNA, sequencing was able to detect mutations in 12 out of 19 cases (63%). Additional experiments with genetically defined standards (EGFR ΔE746-A750/+ and EGFR L858R/+) yielded similar results. Immunohistochemistry (IHC) staining with exon 19-specific antibody was seen in eight out of nine cases with E746-A750del detected by direct sequencing. Neither of the two tumours with complex deletions were positive. Of the five L858R-mutated tumours detected by the PCR methods, only two were positive for the exon 21-specific antibody. The specificity was 100% for both antibodies. The LOD of the real-time PCR method was lower than that of direct sequencing. The mutation specific IHC produced excellent specificity.

Tumor engraftment in nude mice and enrichment in stroma- related gene pathways predict poor survival and resistance to gemcitabine in patients with pancreatic cancer

PURPOSE

The goal of this study was to evaluate prospectively the engraftment rate, factors influencing engraftment, and predictability of clinical outcome of low-passage xenografts from patients with resectable pancreatic ductal adenocarcinoma (PDA) and to establish a bank of PDA xenografts.

EXPERIMENTAL DESIGN

Patients with resectable PDA scheduled for resection at the Johns Hopkins Hospital were eligible. Representative pieces of tumor were implanted in nude mice. The status of the SMAD4 gene and content of tumor-generating cells were determined by immunohistochemistry. Gene expression was carried out by using a U133 Plus 2.0 array. Patients were followed for progression and survival.

RESULTS

A total of 94 patients with PDA were resected, 69 tumors implanted in nude mice, and 42 (61%) engrafted. Engrafted carcinomas were more often SMAD4 mutant, and had a metastatic gene expression signature and worse prognosis. Tumors from patients resistant to gemcitabine were enriched in stroma-related gene pathways. Tumors sensitive to gemcitabine were enriched in cell cycle and pyrimidine gene pathways. The time to progression for patients who received treatment with gemcitabine for metastatic disease (n = 7) was double in patients with xenografts sensitive to gemcitabine.

CONCLUSION

A successful xenograft was generated in 61% of patients attempted, generating a pool of 42 PDA xenografts with significant biological information and annotated clinical data. Patients with PDA and SMAD4 inactivation have a better engraftment rate. Engraftment is a poor prognosis factor, and engrafted tumors have a metastatic gene expression signature. Tumors from gemcitabine-resistant patients were enriched in stromal pathways.

The use of P63 immunohistochemistry for the identification of squamous cell carcinoma of the lung

Introduction

While some targeted agents should not be used in squamous cell carcinomas (SCCs), other agents might preferably target SCCs. In a previous microarray study, one of the top differentially expressed genes between adenocarcinomas (ACs) and SCCs is P63. It is a well-known marker of squamous differentiation, but surprisingly, its expression is not widely used for this purpose. Our goals in this study were (1) to further confirm our microarray data, (2) to analize the value of P63 immunohistochemistry (IHC) in reducing the number of large cell carcinoma (LCC) diagnoses in surgical specimens, and (3) to investigate the potential of P63 IHC to minimize the proportion of “carcinoma NOS (not otherwise specified)” in a prospective series of small tumor samples.

Methods

With these goals in mind, we studied (1) a tissue-microarray comprising 33 ACs and 99 SCCs on which we performed P63 IHC, (2) a series of 20 surgically resected LCCs studied for P63 and TTF-1 IHC, and (3) a prospective cohort of 66 small thoracic samples, including 32 carcinoma NOS, that were further classified by the result of P63 and TTF-1 IHC.

Results

The results in the three independent cohorts were as follows: (1) P63 IHC was differentially expressed in SCCs when compared to ACs (p<0.0001); (2) half of the 20 (50%) LCCs were positive for P63 and were reclassified as SCCs; and (3) all P63 positive cases (34%) were diagnosed as SCCs.

Conclusions

P63 IHC is useful for the identification of lung SCCs.

Integrated preclinical and clinical development of mTOR inhibitors in pancreatic cancer

BACKGROUND

The purpose of this work was to determine the efficacy of inhibiting mammalian target of rapamycin (mTOR) in pancreatic cancer preclinical models and translate preclinical observations to the clinic.

METHODS

Temsirolimus (20 mg Kg(-1) daily) was administered to freshly generated pancreatic cancer xenografts. Tumour growth inhibition was determined after 28 days. Xenografts were characterised at baseline by gene expression and comparative genomic hybridisation. Patients with advanced, gemcitabine-resistant pancreatic cancer were treated with sirolimus (5 mg daily). The primary end point was 6-month survival rate (6mSR). Correlative studies included immunohistochemistry assessment of pathway expression in baseline tumours, drug pharmacokinetics (PKs), response assessment by FDG-PET and pharmacodynamic effects in peripheral-blood mononuclear cells (PBMCs).

RESULTS

In all, 4 of 17 xenografts (23%) responded to treatment. Sensitive tumours were characterised by gene copy number variations and overexpression of genes leading to activation of the PI3K/Akt/mTOR pathway. Activation of p70S6K correlated with drug activity in the preclinical studies. Sirolimus was well tolerated in the clinic, showed predictable PKs, exerted pathway inhibition in post-treatment PBMCs and resulted in a 6mSR of 26%. No correlation, however, was found between activated p70S6K in tumour tissues and anti-tumour effects.

CONCLUSION

Sirolimus activity in pancreatic cancer was marginal and not predicted by the selected biomarker.

Activity of gemcitabine in direct patient-derived xenografts and clinical outcome: Validation of an in vivo model for drug development

4528

Background: Novel drugs are urgently needed for pancreatic ductal adenocarcinoma (PDA). Current preclinical models may not recapitulate the biology of human cancers. Direct xenografts have the potential to better represent the biology of human cancer. We have completed a clinical trial in which surgically resected PDAs were xenografted into nude mice thus generating an in vivo platform for drug development and biomarker identification. Methods: PDAs resected at Johns Hopkins Hospital are implanted into nude mice. From November 2005 to December 2008, 240 patients were consented, 236 operated, 102 were resectable PDAs thus fulfilling the inclusion criteria. 104 patients had other histologies and 34 were unresectable PDAs. Xenografted tumors were treated with gemcitabine and the activity in the xenograft correlated with patient clinical outcome. Results: Out of these 102 cases, 77 were xenografted, 53 were engrafted and reached the treatment phase. 35 out of the 53 originator patients were clinically treated with gemcitabine. The median overall survival of resected patients was 646 days (similar to 660 days from CONKO-001 trial). Patients whose carcinomas engrafted had a shorter median overall survival (319 vs. 728 days, p=0.002), probably reflecting a more aggressive tumor biology in the engrafted group. The response rate of gemcitabine in xenografts based on RECIST criteria was 8% (similar to response rate to gemcitabine in phase III trial by Moore et al.). In the adjuvant setting, the median disease free survival (DFS) was significantly longer in those patients predicted as sensitive by the xenograft model (568 vs. 286 days, p=0.037). In the metastatic setting, the median time to progression (TTP) was longer in those patients predicted as sensitive by the model (126 vs. 73 days) though this difference was not statistically significant. Overall the correlation between gemcitabine activity in this model and clinical outcome as measured by DFS was 0.71 in the subgroup of patients whose xenografts had a TGI lower than -10%. Conclusions: This preclinical model predicts gemcitabine outcome in the clinic in the adjuvant setting. Further studies to analyze the causes of shorter survival in patients whose PDA engrafted are warranted.

No significant financial relationships to disclose.

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

4603

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]

Combined EGFR targeted therapy in a novel in vivo pancreas cancer model

14063

Background: EGFR inhibitors have a definite but limited activity in pancreatic cancer (PaCa). We have reported enhanced activity of dual EGFR therapy with a small molecule inhibitor (erlotinib) plus a monoclonal antibody (cetuximab) in head and neck cancer models. Human xenografted tumors recapitulate better the pathobiology of cancer than existing cell lines. Here we explored a dual EGFR targeting approach using a direct PaCa xenograft model, and sought after markers predicting efficacy. Methods: PaCa specimens obtained at the time surgery were implanted in nude mice and expanded to develop cohorts of tumor bearing mice suitable for drug evaluation. Ten cases were expanded, and within each case 4 groups of 6–8 mice each were treated with vehicle, erlotinib, cetuximab, and the combination of both for 28 days. Gene mutation analysis, gene amplification by fluorescence-in-situ hybridization, and immunohistochemistry (IHC) were done with untreated samples. Results: Two cases were sensitive to both single agents, but the combination did not induce higher efficacy in those. Two additional cases that were resistant to both single agents became sensitive with the combination. No egfr mutations were detected. Three and four cases carried low and high egfr polysomy (defined as [[Unsupported Character - ]] 4 copies in 10–40% and [[Unsupported Character - ]] 40% of the cells, respectively). No correlation was found between egfr copy number and efficacy. By IHC sensitive cases had a lower Ki67 proliferation index, and higher EGFR and nuclear pMAPK staining than resistant cases. The degree of Ki67 decrease after therapy correlated with efficacy. In cases resistant to the single agents but sensitive to the combination nuclear pMAPK only decreased with the dual targeting. Cases with high egfr polysomy were more labile to pharmacodynamic effects after treatment (such as EGFR or pMAPK decreases). Conclusions: EGFR inhibitors showed modest single agent antitumor effect that was enhanced with dual EGFR therapy in PaCa. No genomic markers predicted efficacy, although high egfr polysomy was associated with deeper pharmacodynamic inhibition, conceivably suggesting a phenomenon of pathway addiction. Higher pathway activation by IHC was linked with higher activity.

No significant financial relationships to disclose.

In vivo platform for translational drug development and biomarker discovery in pancreatic cancer

4000

While there are many new agents entering clinical development, there is very little data to prioritize which agents should be explored in pancreas cancer. Furthermore, often there is no information on biomarkers that may predict the activity of these drugs in pancreas cancer. In this project, we have generated a cohort of 30 pancreatic cancer xenografts by implanting in nude mice tumor materials from surgical specimens. Molecular studies show that a) these tumors maintain the genetic features of the originator cancer such as KRAS, p53 and DPC4 gene status; b) tumors represent the heterogeneity of pancreatic cancer well (there is not selection of any genotype in the xenograft ) and c) features do not changed over time. We have used this platform to explore the activity of a battery with a total of 10 new anticancer agents including inhibitors of MAPK, EGFR, mTOR, src kinase, Ras oncogene, mitosis regulators, angiogenesis, heat shock protein and hedgehog pathway inhibitors using a methodology similar to a two stage phase II clinical trial. All agents are tested against 10 xenografts. Those inactive are not explored anymore. Active agents are tested against the full set of tumors. Thus far we have shown that inhibitors of mTOR and MAPK have substantial activity in this model while Ras interacting agents and EGFR targeted drugs have no single agent activity. For active agents, we have characterized the tumors for potential strategies and biormarkers that may predict activity using both a target-focus approach as well as general profiling approach. Signaling inhibitors are more active in tumors with evidence of activation of the targeted pathway. In addition, ex vivo assays indicate that the ability to inhibit the targeted pathway is associated with agent activity. This information may help to prioritize agents for clinical development in pancreatic cancer.

[Table: see text]

Optimizing targeted agents development in pancreatic cancer: A fine-needle aspirate biopsy (FNAB) based ex vivo and in vivo assay

3002

Background: While targeted therapeutics effectively inhibit tumor growth with less toxicity than conventional chemotherapy, in general cancer patients show highly variable responses to them. This study aimed to develop and validate methods that permit the prediction and assessment of the efficacy of targeted therapeutics by using tumor fine needle aspiration biopsy (FNAB) samples Methods: A series of human primary pancreatic cancer were xenografted in nude mice by implanting tumor materials from surgically resected pancreatic cancer patients. Animals were treated with an epidermal growth factor receptor (EGFR) inhibitor, erlotinib, and the mTOR inhibitor temsirolimus or vehicle. Tumors were sampled by FNAB prior to (baseline) and after therapy. Tumor cells obtained by FNAB at baseline were exposed to erlotinib or temsirolimus for six hours ex vivo to prospectively predict tumor response. The degree of inhibition in phosphorylation of ERK1/2 and S6-Ribosomal Protein (S6-RP) downstream to EGFR and mTOR, respectively, were assessed by Western blot to determine the efficacy of the targeted drugs ex vivo and in vivo. The results were correlated with drug-mediated changes in tumor volumes. The effect of drugs on protein phosphorylation ex vivo was also analyzed in patient FNAB samples to show the clinical feasibility of the approach. Results: The degree of inhibition of target pathway activity in tumor cells treated with erlotinib or temsirolimus ex vivo closely correlates with tumor sensitivity in vivo. Xenograft animals sensitive to therapy showed the highest average inhibition of target protein phosphorylation in ex vivo assays, whereas tumors resistant to drugs gave the lowest one. Patient tumor samples yielded adequately cellular material to analyze the effect of erlotinib and temsirolimus in ex vivo assays. Conclusions: FNAB can be used to test ex vivo tumor response to targeted agents. These effects predicted pharmacodynamic as well as antitumor effects in a serie of pancreatic cancer xenografts. Implementation of these novel methods in clinical trials may be useful to identify patients that are likely to benefit from targeted therapeutics before being exposed to drugs and their potential side effects.

No significant financial relationships to disclose.