Overcoming the hurdles: surmounting acquired resistance to anti-EGFR therapy in metastatic colorectal cancer.

Colorectal cancer is the third most prevalent cancer type in the United States, with an alarming incidence and mortality rate, especially among individuals younger than 50 years. The epidermal growth factor receptor (EGFR), essential for cell proliferation and survival, has surfaced as a promising therapeutic target for metastatic colorectal cancer and has demonstrated success in various clinical trials. Monoclonal antibodies such as cetuximab and panitumumab have proven to be effective against EGFR by blocking vital downstream signaling pathways and inhibiting gene transcription and cell proliferation. Despite this promise, most patients eventually develop resistance to anti-EGFR treatment, thereby limiting its long-term efficacy. Genomic alterations, such as mutations in KRAS, NRAS, and BRAF, often bypass the EGFR receptor, promoting resistance to therapy. Although our understanding of primary resistance to anti-EGFR therapy has improved, acquired resistance remains a significant hurdle. This review explores the potential mechanisms underpinning this acquired resistance and strategies to overcome it.

Surgical resection criteria and neoadjuvant therapies for intrahepatic cholangiocarcinoma.

The staging of intrahepatic cholangiocarcinoma (ICC) is complex, and there is no consensus among international cancer groups on how to most appropriately select candidates with nonmetastatic disease for surgical resection. Factors contributing to a higher stage of disease include larger tumor size, multiple tumors, vascular invasion (either portal venous or arterial), biliary invasion, involvement of local hepatic structures, serosal invasion, and regional lymph node metastases. For patients selected to undergo surgery, it is well-documented that R0 resection translates to a survival benefit. Estimating the risk of post-hepatectomy liver failure and post-surgical residual liver function is vital and may preclude some patients with significant tumor burden from undergoing surgery. Numerous serum and biliary biomarkers of the disease can help detect recurrence in patients undergoing surgical resection. Systemic and locoregional neoadjuvant treatments to facilitate better surgical outcomes have yielded mixed results regarding improving resectability and overall survival. Additional research is needed to identify optimal neoadjuvant treatment approaches and to evaluate which patients will benefit most from these strategies. Therapies targeting genetic mutations and protein aberrations found by tumor molecular profiling may offer additional options for future neoadjuvant treatment.

TKIs beyond immunotherapy predict improved survival in advanced HCC.

PURPOSE: For patients with advanced HCC, predictors of immunotherapy response are scarce, and the benefits of tyrosine kinase inhibitor (TKI) treatment after immunotherapy are unclear. We explored whether clinical features, such as target lesion response, immune-mediated toxicity, or subsequent TKI therapy predict immunotherapy response. METHODS: We retrospectively studied 77 patients with advanced HCC receiving immunotherapy. Patient characteristics and outcomes were assessed using various statistical methods, including the log-rank test and Kaplan-Meier methods. Cox proportional hazard modeling was used for multivariable survival analysis. RESULTS: For all patients, median overall survival (mOS) was 13 months (95% CI 8-19), and median progression-free survival (mPFS) was 6 months (95% CI 4-10). Patients with partial response (PR) and stable disease (SD) compared to progressive disease (PD) had prolonged mPFS (27 vs. 5 vs. 1 month(s), p < 0.0001) and mOS (not met vs. 11 vs. 3 months, p < 0.0001). Patients with vs. without immune-mediated toxicities trended towards longer mPFS (9 vs. 4 months p = 0.133) and mOS (17 vs. 9 months; p = 0.095). Patients who did vs. did not receive a tyrosine kinase inhibitor (TKI) after immunotherapy had a significantly improved mOS (19 vs. 5 months, p = 0.0024)). Based on multivariate modeling, the hazard ratio (HR) of overall survival (OS) of patients receiving TKI vs. no TKI was 0.412 (p = 0.0043). CONCLUSION: We show that disease control predicts prolonged mOS and mPFS. Furthermore, TKI therapy administered after immunotherapy predicts prolonged mOS in patients with advanced HCC.

The Role of Immunotherapy in Pancreatic Cancer.

Pancreatic adenocarcinoma remains one of the most lethal cancers globally, with a significant need for improved therapeutic options. While the recent breakthroughs of immunotherapy through checkpoint inhibitors have dramatically changed treatment paradigms in other malignancies based on considerable survival benefits, this is not so for pancreatic cancer. Chemotherapies with modest benefits are still the cornerstone of advanced pancreatic cancer treatment. Pancreatic cancers are inherently immune-cold tumors and have been largely refractory to immunotherapies in clinical trials. Understanding and overcoming the current failures of immunotherapy through elucidating resistance mechanisms and developing novel therapeutic approaches are essential to harnessing the potential durable benefits of immune-modulating therapy in pancreatic cancer patients.

The current state of molecular profiling in gastrointestinal malignancies.

This is a review of the current state of molecular profiling in gastrointestinal (GI) cancers and what to expect from this evolving field in the future. Individualized medicine is moving from broad panel testing of numerous genes or gene products in tumor biopsy samples, identifying biomarkers of prognosis and treatment response, to relatively noninvasive liquid biopsy assays, building on what we have learned in our tumor analysis and growing into its own evolving predictive and prognostic subspecialty. Hence, the field of GI precision oncology is exploding, and this review endeavors to summarize where we are now in preparation for the journey ahead.

A randomized phase II study of SM-88 plus methoxsalen, phenytoin, and sirolimus in patients with metastatic pancreatic cancer treated in the second line and beyond.

BACKGROUND: This trial explores SM-88 used with methoxsalen, phenytoin, and sirolimus (MPS) in pretreated metastatic pancreatic ductal adenocarcinoma (mPDAC) METHODS: Forty-nine patients were randomized to daily 460 or 920 mg oral SM-88 with MPS (SM-88 Regimen). The primary endpoint was objective response rate (RECIST 1.1). RESULTS: Thirty-seven patients completed ≥ one cycle of SM-88 Regimen (response evaluable population). Disease control rate (DCR), overall survival (OS), and progression-free survival (PFS) did not differ significantly between dose levels. Stable disease was achieved in 9/37 patients (DCR, 24.3%); there were no complete or partial responses. Quality-of-life (QOL) was maintained and trended in favor of 920 mg. SM-88 Regimen was well tolerated; a single patient (1/49) had related grade 3 and 4 adverse events, which later resolved. In the intention-to-treat population of 49 patients, the median overall survival (mOS) was 3.4 months (95% CI: 2.7-4.9 months). Those treated in the second line had an mOS of 8.1 months and a median PFS of 3.8 months. Survival was higher for patients with stable versus progressive disease (any line; mOS: 10.6 months vs. 3.9 months; p = 0.01). CONCLUSIONS: SM-88 Regimen has a favorable safety profile with encouraging QOL effects, disease control, and survival trends. This regimen should be explored in the second-line treatment of patients with mPDAC. CLINICALTRIALS: gov Identifier: NCT03512756.

Impact of Sociodemographic Disparities and Insurance Status on Survival of Patients with Early-Onset Colorectal Cancer.

BACKGROUND: Low socioeconomic status (SES) has been linked to worse survival in patients with colorectal cancer (CRC); however, the impact of SES on early-onset CRC remains undescribed. MATERIALS AND METHODS: Retrospective analysis of data from the National Cancer Database (NCDB) between 2004 and 2016 was conducted. We combined income and education to form a composite measure of SES. Logistic regression and χ2 testing were used to examine early-onset CRC according to SES group. Survival rates and Cox proportional hazards models compared stage-specific overall survival (OS) between the SES groups. RESULTS: In total, 30,903 patients with early-onset CRC were identified, of whom 78.7% were White; 14.5% were Black. Low SES compared with high SES patients were more likely to be Black (26.3% vs. 6.1%) or Hispanic (25.3% vs. 10.5%), have T4 tumors (21.3% vs. 17.8%) and/or N2 disease (13% vs. 11.1%), and present with stage IV disease (32.8% vs. 27.7%) at diagnosis (p < .0001, all comparisons). OS gradually improved with increasing SES at all disease stages (p < .001). In stage IV, the 5-year survival rate was 13.9% vs. 21.7% for patients with low compared with high SES. In multivariable analysis, SES (low vs. high group; adjusted hazard ratio [HRadj ], 1.35; 95% confidence interval [CI], 1.26-1.46) was found to have a significant effect on survival (p < .0001) when all of the confounding variables were adjusted. Insurance (not private vs. private; HRadj , 1.38; 95% CI, 1.31-1.44) mediates 31% of the SES effect on survival. CONCLUSION: Patients with early-onset CRC with low SES had the worst outcomes. Our data suggest that SES should be considered when implementing programs to improve the early detection and treatment of patients with early-onset CRC. IMPLICATIONS FOR PRACTICE: Low socioeconomic status (SES) has been linked to worse survival in patients with colorectal cancer (CRC); however, the impact of SES on early-onset CRC remains undescribed. In this retrospective study of 30,903 patients with early-onset CRC in the National Cancer Database, a steady increase in the yearly rate of stage IV diagnosis at presentation was observed. The risk of death increased as socioeconomic status decreased. Race and insurance status were independent predictors for survival. Implementation of programs to improve access to care and early diagnostic strategies among younger adults, especially those with low SES, is warranted.

A phase I trial of the mTOR inhibitor temsirolimus in combination with capecitabine in patients with advanced malignancies.

BACKGROUND: Temsirolimus is an mTOR antagonist with proven anticancer efficacy. Preclinical data suggest greater anticancer effect when mTOR inhibitors are combined with cytotoxic chemotherapy. We performed a Phase I assessment of the combination of temsirolimus and capecitabine in patients with advanced solid tumors. METHODS: Patients were enrolled in an alternating dose escalation of temsirolimus (at 15 or 25 mg IV weekly) and capecitabine (at 750, 1000, and 1250 mg/m2 twice daily) in separate Q2-week and Q3-week cohorts. At the recommended Phase II doses (RP2Ds) of temsirolimus and capecitabine (Q2), seven patients were also treated with oxaliplatin (85 mg/m2 , day 1) to determine triplet combination safety and efficacy. RESULTS: Forty-five patients were enrolled and 41 were evaluable for dose-limiting toxicities (DLTs). The most common adverse events (AEs) were mucositis, fatigue, and thrombocytopenia. The most common grade 3/4 AEs were hypophosphatemia and anemia. Five patients had DLTs, including hypophosphatemia, mucositis, and thrombocytopenia. The RP2Ds were temsirolimus 25 mg +capecitabine 1000 mg/m2 (Q2); and temsirolimus 25 mg +capecitabine 750 mg/m2  (Q3). Of the 38 patients evaluable for response, one had a partial response (PR) and 19 had stable disease (SD). The overall disease control rate was 52%. Five of the 20 patients with SD/PR maintained disease control for >6 months. CONCLUSIONS: The combination of temsirolimus and capecitabine is safe on both a Q2-week and a Q3-week schedule. The combination demonstrated promising evidence of disease control in this highly refractory population and could be considered for testing in disease-specific phase II trials.

A Pilot Trial of Molecularly Tailored Therapy for Patients with Metastatic Pancreatic Ductal Adenocarcinoma.

Purpose: Despite the wide adoption of tumor molecular profiling, there is a dearth of evidence linking molecular biomarkers for treatment selection to prediction of treatment outcomes in patients with metastatic pancreatic cancer. We initiated a pilot study to test the feasibility of designing a larger phase II trial of molecularly tailored treatment for metastatic pancreatic cancer. Methods: Our study aimed to assess the feasibility of following a treatment algorithm based on the expression of three published predictive markers of response to chemotherapy: ribonucleotide reductase catalytic subunit M1 (for gemcitabine); excision repair cross-complementation group 1 (for platinum agents); and thymidylate synthase (for 5-fluorouracil) in patients with untreated, metastatic pancreatic cancer. Results of the tumor biopsy analysis were used to assign patients to one of seven doublet regimens. Key secondary objectives included response rate (RR), disease control rate (DCR), progression-free survival (PFS), and overall survival (OS). Results: Between December 2012 and March 2015, 30 patients were enrolled into the study. Ten patients failed screening primarily due to inadequate tumor tissue availability. Of the remaining 20 patients, 19 were assigned into 6 different chemotherapy doublets, and achieved an RR of 28%, with a DCR rate of 78%. The median PFS and OS were 5.78 and 8.21 months, respectively. Conclusions: The incorporation of biomarkers into a treatment algorithm is feasible and resulted in a PFS and OS similar to other doublet therapies for patients with metastatic pancreatic cancer. Based on the results from this pilot study, a larger phase II randomized trial of molecularly targeted therapy versus physicians' choice of standard of care has been initiated in the second-line setting (NCT02967770).

A phase I study of intravenous artesunate in patients with advanced solid tumor malignancies.

PURPOSE: The artemisinin class of anti-malarial drugs has shown significant anti-cancer activity in pre-clinical models. Proposed anti-cancer mechanisms include DNA damage, inhibition of angiogenesis, TRAIL-mediated apoptosis, and inhibition of signaling pathways. We performed a phase I study to determine the maximum tolerated dose (MTD) and dose-limiting toxicities (DLTs) of intravenous artesunate (IV AS). METHODS: Patients were enrolled in an accelerated titration dose escalation study with planned dose levels of 8, 12, 18, 25, 34 and 45 mg/kg given on days 1 and 8 of a 21-day cycle. Toxicities were assessed using the NCI CTCAE (ver. 4.0), and response was assessed using RECIST criteria (version 1.1). Pharmacokinetic (PK) studies were performed during cycle 1. RESULTS: A total of 19 pts were enrolled, 18 of whom were evaluable for toxicity and 15 were evaluable for efficacy. DLTs were seen at dosages of 12 (1 of 6 patients), 18 (1 of 6) and 25 mg/kg (2 of 2), and were neutropenic fever (Gr 4), hypersensitivity reaction (Gr 3), liver function test abnormalities (Gr 3/4) along with neutropenic fever, and nausea/vomiting (Gr 3) despite supportive care. The MTD was determined to be 18 mg/kg. No responses were observed, while four patients had stable disease, including three with prolonged stable disease for 8, 10, and 11 cycles, for a disease control rate of 27%. PK parameters of AS and its active metabolite, dihydroartemisinin (DHA), correlated with dose. CONCLUSION: The MTD of intravenous artesunate is 18 mg/kg on this schedule. Treatment was well tolerated. Modest clinical activity was seen in this pre-treated population. CLINICALTRIALS. GOV IDENTIFIER: NCT02353026.

Regorafenib in advanced hepatocellular carcinoma (HCC): considerations for treatment.

PURPOSE: We report our institutional observations of ten patients with advanced hepatocellular carcinoma (HCC) (seven and three were Child-Pugh class A and B, respectively) who received compassionate regorafenib therapy between June 2016 and January 2017. These patients did not fit the rigid criteria of a clinical trial and represented the use of regorafenib in an everyday clinic situation. METHODS: Regorafenib (160 mg P.O. daily) was administered to patients on a 4-week cycle (3 weeks on, 1 week off) until disease progression (assessed using mRECIST criteria) or discontinuation secondary to toxicity (assessed using CTCAE criteria). Relevant clinical data were abstracted from patient medical records and reviewed retrospectively. RESULTS: The median duration of patient treatment was 6.6 weeks, and the median time to disease progression was 12.5 weeks. Most common treatment emergent adverse events were fatigue, diarrhea, and hand-foot skin reaction. Elevated AST and ALT were the most commonly observed laboratory-assessed adverse events, which reached grade 3 status in the Child-Pugh class B patients only. We observed intolerance to regorafenib treatment in one patient who had previously received a liver transplant. We also saw lithium toxicity in one patient receiving long-term lithium treatment, suggesting a potential and unexpected drug-drug interaction with regorafenib. CONCLUSIONS: Taken together, our observations indicate that regorafenib is beneficial in the treatment of patients with advanced HCC who progressed on or demonstrated intolerance to sorafenib therapy; however, careful selection and close monitoring of patients is necessary to maximize the benefit while minimizing the toxicities of regorafenib treatment.

Precision Medicine in Metastatic Colorectal Cancer: Relevant Carcinogenic Pathways and Targets-PART 1: Biologic Therapies Targeting the Epidermal Growth Factor Receptor and Vascular Endothelial Growth Factor.

The survival of patients with metastatic colorectal cancer has improved dramatically in recent years, with overall survival exceeding 3 years in large randomized clinical trials. There are now several treatment options for patients with metastatic colorectal cancer. In addition to chemotherapy backbones utilizing fluoropyrimidine, oxaliplatin, and irinotecan combinations, biologic agents that target specific oncogenic pathways have contributed to the improved survival observed in this patient population. This class of medications includes epidermal growth factor receptor (EGFR)-targeted drugs (cetuximab and panitumumab) and vascular endothelial growth factor (VEGF)-targeted therapies (bevacizumab, ramucirumab, ziv-aflibercept, and regorafenib). Bevacizumab remains the only VEGF-targeted agent approved by the US Food and Drug Administration in the first-line metastatic setting. EGFR-directed treatment should be restricted to patients with extended RAS and BRAF wild-type tumors. Tumor sidedness may be a more powerful prognostic and predictive biomarker than tumor mutational profile. Patients with left-sided primary tumors derive greater benefit from EGFR-targeted therapies whereas patients with right-sided primary tumors benefit more from bevacizumab. Herein we review drugs that target the EGFR and VEGF pathways, focusing on patient selection, drug toxicities, and how to choose agents for first-line therapy.

Precision Medicine in Metastatic Colorectal Cancer: Relevant Carcinogenic Pathways and Targets-PART 2: Approaches Beyond First-Line Therapy, and Novel Biologic Agents Under Investigation.

A frequent quandary for oncologists is the selection of chemotherapy and biologic therapy for patients with metastatic colorectal cancer in second-line and higher treatment settings. While not approved by the US Food and Drug Administration (FDA) in the first-line setting, the vascular endothelial growth factor (VEGF)-targeting agents ziv-aflibercept and ramucirumab are appropriate treatment options in the second-line setting, as is continuation of first-line bevacizumab. Tumor RAS mutational status is helpful to determine which patients may benefit from epidermal growth factor receptor (EGFR)-directed therapies, and other novel biomarkers (BRAF, HER2, and mismatch repair deficiency) allow us to select patients who may benefit from biologic therapies that are FDA-approved for other malignancies. Maintenance therapy for patients with stable disease following first-line therapy is a unique clinical situation that warrants special attention. Immunotherapy has thus far been ineffective for patients with mismatch repair-proficient tumors, but novel combination strategies are being studied to break through this treatment barrier. Finally, several new biologic therapies with novel targets are under development and will likely contribute to the growing arsenal of treatment options for patients with metastatic colorectal cancer.

Neoadjuvant Combined-Modality Therapy for Locally Advanced Rectal Cancer and Its Future Direction.

Rectal cancer treatment presents a challenge, and its optimal management requires a multidisciplinary approach involving surgical, medical, and radiation oncologists. Advances in surgical techniques, radiotherapy, and medical imaging technology have transformed the therapeutic landscape and have led to substantial improvements in both local disease control and patient survival. The currently established standard of care for patients with locally advanced rectal cancer involves preoperative (neoadjuvant) concurrent radiotherapy and infusional fluorouracil-based or oral capecitabine-based chemotherapy, also known as chemoradiotherapy (CRT), followed by surgery. Surgery is often followed by adjuvant chemotherapy. Here we discuss the evolution of standard therapy for rectal cancer patients and the use of preoperative CRT for the treatment of locally advanced disease. Treatment schemes that have attempted to broaden the horizons of standard therapy include the use of induction chemotherapy and "watch-and-wait" approaches. We examine several novel trials using these and other treatment approaches, which may eventually lead to better patient selection and the avoidance of overtreatment and unnecessary adverse effects.

A paradigm shift from one-size-fits-all to tailor-made therapy for metastatic colorectal cancer.

Colorectal cancer is the second leading cause of cancer death in the United States. At least 50% of patients develop metastases, and most of these patients have unresectable tumors. Treatment options for metastatic colorectal cancer (mCRC) include several lines of chemotherapy, salvage surgery, maintenance therapy, and local therapy. For decades, 5-fluorouracil (5-FU) was the only chemotherapy option for patients with mCRC. This changed markedly over the last decade with the approval of irinotecan, oxaliplatin, capecitabine, humanized monoclonal antibodies that target either vascular endothelial growth factor (bevacizumab, aflibercept, and ramucirumab) or the epidermal growth factor receptor (cetuximab and panitumumab), and, most recently, regorafenib and trifluridine/tipiracil. In this review, we focus on first-line treatments for mCRC. We discuss how results from multiple clinical trials over the last 10 to 20 years confirmed the benefit of adding oxaliplatin and irinotecan to the established 5-FU chemotherapy backbone, and then further defined benefit in certain patient subgroups with the addition of mAbs. Ongoing investigations attempt to illustrate the role of newer molecular and immune therapies in the fight against mCRC. We acknowledge the tremendous advances made in first-line mCRC treatment, admit that we still have a long way to go, and highlight exciting lines of research for patients with mCRC in the burgeoning fields of precision medicine and immunotherapy.

Exceptional Response to Systemic Therapy in Advanced Metastatic Gastric Cancer: A Case Report.

Gastroesophageal adenocarcinomas represent one of the top five most common types of cancer worldwide. Despite significant advancement, it is still not known which first-line chemotherapy option is best matched to an individual patient. The vast advances in molecular biology have led to the discovery of many potential predictive biomarkers, such as HER-2 neu, thymidylate synthase (TS), excision repair cross-complementation group 1 (ERCC1), and topoisomerase-1 (TOPO1). These markers could allow us to select treatment based on an individual's tumor profile, resulting in an improvement of outcome. Our report highlights two patients with metastatic gastric cancer that achieved an exceptional response with traditional therapy and provides insights into the future perspectives of molecular profile-directed chemotherapy.

Pancreatic cancer, treatment options, and GI-4000.

Although pancreatic cancer is but the eleventh most prevalent cancer in the US, it is predicted that of all the patients newly diagnosed with this disease in 2014, only 27% will still be alive at the end of the first year, which is reduced to 6% after 5 years. The choice of chemotherapy in the treatment of pancreatic cancer is dependent on disease stage and patient performance status but, in general, the most widely used approved regimens include 5-fluorouracil (5-FU) combinations and gemcitabine combinations. Recent therapeutic strategies have resulted in an improvement in survival of patients with pancreatic cancer but the magnitude of change is disappointing and vast improvements are still needed. The goal of immunotherapy is to enhance and guide the body's immune system to recognize tumor-specific antigens and mount an attack against the disease. Among newer immune therapies, GI-4000 consists of 4 different targeted molecular immunogens, each containing a different Ras protein (antigen) encoded by the most commonly found mutant RAS genes in solid tumors-RAS mutations exist in over 90% of pancreatic ductal adenocarcinomas. We will review pancreatic cancer epidemiology and its current treatment options, and consider the prospects of immunotherapy, focusing on GI-4000. We discuss the potential mechanism of action of GI-4000, and the performance of this vaccination series thus far in early phase clinical trials.

Irreversible multitargeted ErbB family inhibitors for therapy of lung and breast cancer.

Overactivation of the ErbB protein family, which is comprised of 4 receptor tyrosine kinase members (ErbB1/epidermal growth factor receptor [EGFR]/HER1, ErbB2/HER2, ErbB3/HER3, and ErbB4/HER4), can drive the development and progression of a wide variety of malignancies, including colorectal, head and neck, and certain non-small cell lung cancers (NSCLCs). As a result, agents that target a specific member of the ErbB family have been developed for the treatment of cancer. These agents include the reversible EGFR tyrosine kinase inhibitors (TKIs) erlotinib and gefitinib; the EGFR-targeting monoclonal antibodies cetuximab and panitumumab; and the HER2-targeting monoclonal antibody trastuzumab. Lapatinib is a dual TKI that targets both EGFR and HER2. In addition, TKIs that inhibit multiple members of the ErbB family and also bind their targets irreversibly are under evaluation for the treatment of cancer. Three such compounds have progressed into clinical studies: the EGFR, HER2, and HER4 inhibitors afatinib, dacomitinib, and neratinib. Phase I studies of these agents have shown clinical activity in NSCLC, breast cancer, and other malignancies. Currently, afatinib is approved for EGFR mutation-positive NSCLC and is in development for squamous NSCLC, and dacomitinib is in phase III of clinical development for NSCLC, neratinib is in phase III of clinical development for the treatment of breast cancer, and afatinib is also in phase III development in head and neck cancer. Final results from clinical trials may lead to the potential approval of these agents in a variety of solid tumor malignancies.

Pancreatic cancer, treatment options, and GI-4000.

Although pancreatic cancer is but the eleventh most prevalent cancer in the US, it is predicted that of all the patients newly diagnosed with this disease in 2014, only 27% will still be alive at the end of the first year and only 6% will make it past 5 years. The choice of chemotherapy in the treatment of pancreatic cancer is dependent on disease stage and patient performance status but, in general, the most widely used approved regimens include 5-fluorouracil (5-FU) combinations and gemcitabine combinations. Recent therapeutic strategies have resulted in an improvement in survival of patients with pancreatic cancer but the magnitude of change is disappointing and vast improvements are still needed. The goal of immunotherapy is to enhance and guide the body's immune system to recognize tumor-specific antigens and mount an attack against the disease. Among newer immune therapies, GI-4000 consists of 4 different targeted molecular immunogens, each containing a different Ras protein (antigen) encoded by the most commonly found mutant RAS genes in solid tumors--RAS mutations exist in over 90% of pancreatic ductal adenocarcinomas. We will review pancreatic cancer epidemiology and its current treatment options, and consider the prospects of immunotherapy, focusing on GI-4000. We discuss the potential mechanism of action of GI-4000, and the performance of this vaccination series thus far in early phase clinical trials.

A Phase I clinical trial of the combination of imatinib and paclitaxel in patients with advanced or metastatic solid tumors refractory to standard therapy.

PURPOSE: Pre-clinical data suggest that combining imatinib with traditional cytotoxic chemotherapy may improve imatinib efficacy. We conducted a Phase I study of imatinib in combination with paclitaxel in patients with advanced or metastatic solid tumors. METHODS: Patients were accrued to the study in a standard 3 + 3 design. Patients were restaged every two cycles, and those with stable disease (SD), or better, continued study treatment without interruption. Maximally tolerated doses (MTDs) and pharmacokinetic profiles of combination imatinib and paclitaxel were assessed. RESULTS: Fifty-eight patients were enrolled, including 40 in the Phase I dose escalation portion. Alternating dose escalation of imatinib and paclitaxel on a 28-day cycle resulted in MTDs of 800 mg imatinib daily, on days 1-4, 8-11, 15-18, and 22-25, and 100 mg/m(2) paclitaxel weekly, on days 3, 10, and 17. Two expansion cohorts, comprising 10 breast cancer patients and 8 patients with soft-tissue sarcomas, were enrolled at the MTDs. The most common adverse events were flu-like symptoms (64 %) and nausea/vomiting (71 %). The most common Grade 3/4 toxicities were neutropenia (26 %), flu-like symptoms (12 %), and pain (12 %). There were no relevant differences in the pharmacokinetic profiles of either drug when given in combination compared with alone. Thirty-eight subjects were evaluable for response, 18 (47.4 %) of whom experienced clinical benefit. Five patients (13.2 %) had a partial response (PR) and 13 patients (34.2 %) had SD; the average time to progression in those with clinical benefit was 17 weeks (range: 7-28 weeks). CONCLUSIONS: This combination of imatinib and paclitaxel was reasonably safe and tolerable, and demonstrated evidence of anti-tumor activity. Further exploration in disease-specific Phase II trials is warranted.