Andrew H. Ko

Subtypes of pancreatic ductal adenocarcinoma and their differing responses to therapy

Pancreatic ductal adenocarcinoma (PDA) is a lethal disease. Overall survival is typically 6 months from diagnosis. Numerous phase 3 trials of agents effective in other malignancies have failed to benefit unselected PDA populations, although patients do occasionally respond. Studies in other solid tumors have shown that heterogeneity in response is determined, in part, by molecular differences between tumors. Furthermore, treatment outcomes are improved by targeting drugs to tumor subtypes in which they are selectively effective, with breast and lung cancers providing recent examples. Identification of PDA molecular subtypes has been frustrated by a paucity of tumor specimens available for study. We have overcome this problem by combined analysis of transcriptional profiles of primary PDA samples from several studies, along with human and mouse PDA cell lines. We define three PDA subtypes: classical, quasimesenchymal and exocrine-like, and we present evidence for clinical outcome and therapeutic response differences between them. We further define gene signatures for these subtypes that may have utility in stratifying patients for treatment and present preclinical model systems that may be used to identify new subtype specific therapies.

Serum CA19-9 response as a surrogate for clinical outcome in patients receiving fixed-dose rate gemcitabine for advanced pancreatic cancer.

The use of serial serum measurements of the carbohydrate antigen 19-9 (CA19-9) to guide treatment decisions and serve as a surrogate end point in clinical trial design requires further validation. We investigated whether CA19-9 decline represents an accurate surrogate for survival and time to treatment failure (TTF) in a cohort of 76 patients with advanced pancreatic cancer receiving fixed-dose rate gemcitabine in three separate studies. Statistically significant correlations between percentage CA19-9 decline and both overall survival and TTF were found, with median survival ranging from 12.0 months for patients with the greatest degree of biomarker decline (>75%) compared with 4.3 months in those whose CA19-9 did not decline during therapy (P<0.001). Using specific thresholds, patients with ⩾25% decline in CA19-9 during treatment had significantly better outcomes than those who did not (median survival and TTF of 9.6 and 4.6 months vs 4.4 and 1.5 months; P<0.001). Similar results were seen using both 50 and 75% as cutoff points. We conclude that serial CA19-9 measurements correlate well with clinical outcomes in this patient population, and that decline in this biomarker should be entertained for possible use as a surrogate end point in clinical trials for the selection of new treatments in this disease.

Characterization of circulating tumor cell aggregates identified in patients with epithelial tumors

Circulating tumor cells (CTCs) have been implicated as a population of cells that may seed metastasis and venous thromboembolism (VTE), two major causes of mortality in cancer patients. Thus far, existing CTC detection technologies have been unable to reproducibly detect CTC aggregates in order to address what contribution CTC aggregates may make to metastasis or VTE. We report here an enrichment-free immunofluorescence detection method that can reproducibly detect and enumerate homotypic CTC aggregates in patient samples. We identified CTC aggregates in 43% of 86 patient samples. The fraction of CTC aggregation was investigated in blood draws from 24 breast, 14 non-small cell lung, 18 pancreatic, 15 prostate stage IV cancer patients and 15 normal blood donors. Both single CTCs and CTC aggregates were measured to determine whether differences exist in the physical characteristics of these two populations. Cells contained in CTC aggregates had less area and length, on average, than single CTCs. Nuclear to cytoplasmic ratios between single CTCs and CTC aggregates were similar. This detection method may assist future studies in determining which population of cells is more physically likely to contribute to metastasis and VTE.

Vaccination of metastatic colorectal cancer patients with matured dendritic cells loaded with multiple major histocompatibility complex class I peptides.

Developing a process to generate dendritic cells (DCs) applicable for multicenter trials would facilitate cancer vaccine development. Moreover, targeting multiple antigens with such a vaccine strategy could enhance the efficacy of such a treatment approach. We performed a phase 1/2 clinical trial administering a DC-based vaccine targeting multiple tumor-associated antigens to patients with advanced colorectal cancer (CRC). A qualified manufacturing process was used to generate DC from blood monocytes using granulocyte macrophage colony-stimulating factor and IL-13, and matured for 6 hours with Klebsiella-derived cell wall fraction and interferon-gamma (IFN-γ). DCs were also loaded with 6 HLA-A*0201 binding peptides derived from carcinoembryonic antigen (CEA), MAGE, and HER2/neu, as well as keyhole limpet hemocyanin protein and pan-DR epitope peptide. Four planned doses of 35×106 cells were administered intradermally every 3 weeks. Immune response was assessed by IFN-γ enzyme-linked immunosorbent spot (ELISPOT). Matured DC possessed an activated phenotype and could prime T cells in vitro. In the trial, 21 HLA-A2+ patients were apheresed, 13 were treated with the vaccine, and 11 patients were evaluable. No significant treatment-related toxicity was reported. T-cell responses to a CEA-derived peptide were detected by ELISPOT in 3 patients. T cells induced to CEA possessed high avidity T-cell receptors. ELISPOT after in vitro restimulation detected responses to multiple peptides in 2 patients. All patients showed progressive disease. This pilot study in advanced CRC patients demonstrates DC-generated granulocyte macrophage colony-stimulating factor and IL-13 matured with Klebsiella-derived cell wall fraction and IFN-γ can induce immune responses to multiple tumor-associated antigens in patients with advanced CRC.

Locally Advanced, Unresectable Pancreatic Cancer: American Society of Clinical Oncology Clinical Practice Guideline

PURPOSE To provide evidence-based recommendations to oncologists and others for treatment of patients with locally advanced, unresectable pancreatic cancer. METHODS American Society of Clinical Oncology convened an Expert Panel of medical oncology, radiation oncology, surgical oncology, gastroenterology, palliative care, and advocacy experts and conducted a systematic review of the literature from January 2002 to June 2015. Outcomes included overall survival, disease-free survival, progression-free survival, and adverse events. RESULTS Twenty-six randomized controlled trials met the systematic review criteria. RECOMMENDATIONS A multiphase computed tomography scan of the chest, abdomen, and pelvis should be performed. Baseline performance status and comorbidity profile should be evaluated. The goals of care, patient preferences, psychological status, support systems, and symptoms should guide decisions for treatments. A palliative care referral should occur at first visit. Initial systemic chemotherapy (6 months) with a combination regimen is recommended for most patients (for some patients radiation therapy may be offered up front) with Eastern Cooperative Oncology Group performance status 0 or 1 and a favorable comorbidity profile. There is no clear evidence to support one regimen over another. The gemcitabine-based combinations and treatments recommended in the metastatic setting (eg, fluorouracil, leucovorin, irinotecan, and oxaliplatin and gemcitabine plus nanoparticle albumin-bound paclitaxel) have not been evaluated in randomized controlled trials involving locally advanced, unresectable pancreatic cancer. If there is local disease progression after induction chemotherapy, without metastasis, then radiation therapy or stereotactic body radiotherapy may be offered also with an Eastern Cooperative Oncology Group performance status ≤ 2 and an adequate comorbidity profile. If there is stable disease after 6 months of induction chemotherapy but unacceptable toxicities, radiation therapy may be offered as an alternative. Patients with disease progression should be offered treatment per the ASCO Metastatic Pancreatic Cancer Treatment Guideline. Follow-up visits every 3 to 4 months are recommended. Additional information is available at www.asco.org/guidelines/LAPC and www.asco.org/guidelines/MetPC and www.asco.org/guidelineswiki.

Phase II Study of Fixed Dose Rate Gemcitabine With Cisplatin for Metastatic Adenocarcinoma of the Pancreas

PURPOSE Although gemcitabine remains the standard of care for patients with advanced pancreatic cancer, additional improvements may be realized by combining therapeutic agents with synergistic activity, and optimizing drug delivery using pharmacokinetic principles such as fixed dose rate (FDR) infusion. The objectives of this study were to determine safety and efficacy in patients with metastatic pancreatic cancer treated with FDR gemcitabine in combination with low-dose cisplatin. PATIENTS AND METHODS Chemotherapy-naive patients with metastatic pancreatic adenocarcinoma were treated with a combination of gemcitabine 1,000 mg/m2 at 10 mg/m2/min together with cisplatin 20 mg/m2 on days 1 and 8 of a 21-day cycle. Patient follow-up was performed using computerized tomographic scans and serial CA 19-9 measurements. RESULTS A total of 51 patients were enrolled onto the study, with a median follow-up time of 215 days. Twenty-two of 40 patients (55.0%) with a baseline serum CA 19-9 level > or = 2x the upper limit of normal demonstrated a > or = 50% biomarker decline during treatment. Nine of 47 patients (19.1%) with measurable disease achieved a partial response, and 28 patients (59.6%) had disease stabilization for at least two treatment cycles. Median time to progression was 3.9 months and median survival was 7.1 months, with an estimated 1-year survival rate of 29%. The most frequently reported grade 3 or 4 adverse events were neutropenia (52.9%) and thrombocytopenia (15.7%). Most patients were switched to an every-other-week dosing schedule. CONCLUSION The combination of FDR gemcitabine and cisplatin is well tolerated and appears to be an acceptable, albeit not clearly superior, alternative to other gemcitabine/platinum regimens for the treatment of metastatic pancreatic cancer.

Cell-Free DNA Next-Generation Sequencing in Pancreatobiliary Carcinomas

UNLABELLED Patients with pancreatic and biliary carcinomas lack personalized treatment options, in part because biopsies are often inadequate for molecular characterization. Cell-free DNA (cfDNA) sequencing may enable a precision oncology approach in this setting. We attempted to prospectively analyze 54 genes in tumor and cfDNA for 26 patients. Tumor sequencing failed in 9 patients (35%). In the remaining 17, 90.3% (95% confidence interval, 73.1%-97.5%) of mutations detected in tumor biopsies were also detected in cfDNA. The diagnostic accuracy of cfDNA sequencing was 97.7%, with 92.3% average sensitivity and 100% specificity across five informative genes. Changes in cfDNA correlated well with tumor marker dynamics in serial sampling (r = 0.93). We demonstrate that cfDNA sequencing is feasible, accurate, and sensitive in identifying tumor-derived mutations without prior knowledge of tumor genotype or the abundance of circulating tumor DNA. cfDNA sequencing should be considered in pancreatobiliary cancer trials where tissue sampling is unsafe, infeasible, or otherwise unsuccessful. SIGNIFICANCE Precision medicine efforts in biliary and pancreatic cancers have been frustrated by difficulties in obtaining adequate tumor tissue for next-generation sequencing. cfDNA sequencing reliably and accurately detects tumor-derived mutations, paving the way for precision oncology approaches in these deadly diseases.

Pancreatic adenocarcinoma, version 2.2017: Clinical practice guidelines in Oncology

Ductal adenocarcinoma and its variants account for most pancreatic malignancies. High-quality multiphase imaging can help to preoperatively distinguish between patients eligible for resection with curative intent and those with unresectable disease. Systemic therapy is used in the neoadjuvant or adjuvant pancreatic cancer setting, as well as in the management of locally advanced unresectable and metastatic disease. Clinical trials are critical for making progress in treatment of pancreatic cancer. The NCCN Guidelines for Pancreatic Adenocarcinoma focus on diagnosis and treatment with systemic therapy, radiation therapy, and surgical resection.

Serum CA19-9 decline compared to radiographic response as a surrogate for clinical outcomes in patients with metastatic pancreatic cancer receiving chemotherapy.

Objective: Serum carbohydrate antigen 19-9 (CA19-9) has never been compared to radiographic objective response as a surrogate for clinical outcomes in patients receiving chemotherapy for metastatic pancreatic cancer. Methods: We compared CA19-9 decline to objective response as surrogate end points for both time to progression (TTP) and overall survival (OS) in patients with metastatic pancreatic cancer receiving fixed-dose rate gemcitabine. Results: A total of 75 patients from 2 studies were eligible for analysis. Significant correlations were observed between maximum CA19-9 decline and both TTP (P < 0.0001) and OS (P < 0.0001). Median OS was 12.2 months for patients with more than a 75% decline in CA19-9, 7.5 months for those with 0% to 75% decline, and3.5 months for those with no decline. Correlations between bestradiographic response and both TTP (P < 0.0001) and OS (P=0.0013) were also observed. Median OS was 12.8 months for patients with partial or complete response, 8.0 months for those with stable disease, and 4.6 months for those with progressive disease. Conclusions: CA19-9 decline compares favorably with objective response asastrong predictor of TTP and OS. CA19-9 could represent amore cost-effective tool for the evaluation of new therapies and guidance of clinical management in patients with metastatic pancreatic cancer.

A Phase I Study of a 2-Day Lapatinib Chemosensitization Pulse Preceding Nanoparticle Albumin-Bound Paclitaxel for Advanced Solid Malignancies

Purpose: Systemic chemotherapy fails to access much of the tumor burden in patients with advanced cancer, significantly limiting its efficacy. In preclinical studies, brief high doses of tyrosine kinase inhibitors (TKI) targeting the human epidermal growth factor receptor (HER) family can prime tumor vasculature for optimal chemotherapeutic delivery and efficacy. This study investigates the clinical relevance of this approach. Experimental Design: A phase I clinical study of escalating doses of the HER TKI lapatinib given as a 2-day pulse before a weekly infusion of nab-paclitaxel (100 mg/m2) was conducted in patients with advanced solid tumors. Results: Twenty-five patients were treated. Treatment was associated with grade 1 to 2 toxicities including diarrhea, nausea, rash, neutropenia, neuropathy, fatigue, alopecia, and anemia. The two dose-limiting toxicities were grade 3 vomiting and grade 4 neutropenia, and the maximum tolerated dose of lapatinib was defined as 5250 mg/day in divided doses. Lapatinib concentrations increased with increasing dose. Dynamic Contrast Enhanced Magnetic Resonance Imaging studies in a subset of patients confirmed a decrease in tumor vascular permeability immediately following a lapatinib pulse. Sixty-five percent of evaluable patients experienced a partial or stable response on this therapy, 72% of whom were previously taxane-refractory. Conclusion: A 2-day pulse of high-dose lapatinib given before weekly nab-paclitaxel is a feasible and tolerable clinical regimen, suitable for testing this novel vascular-priming chemosensitization hypothesis developed in preclinical models. (Clin Cancer Res 2009;15(17):5569–75)