FDG PET/CT Imaging 1 Week after a Single Dose of Pembrolizumab Predicts Treatment Response in Patients with Advanced Melanoma.

PURPOSE: Immunologic response to anti-programmed cell death protein 1 (PD-1) therapy can occur rapidly with T-cell responses detectable in as little as one week. Given that activated immune cells are FDG avid, we hypothesized that an early FDG PET/CT obtained approximately 1 week after starting pembrolizumab could be used to visualize a metabolic flare (MF), with increased tumor FDG activity due to infiltration by activated immune cells, or a metabolic response (MR), due to tumor cell death, that would predict response. PATIENTS AND METHODS: Nineteen patients with advanced melanoma scheduled to receive pembrolizumab were prospectively enrolled. FDG PET/CT imaging was performed at baseline and approximately 1 week after starting treatment. FDG PET/CT scans were evaluated for changes in maximum standardized uptake value (SUVmax) and thresholds were identified by ROC analysis; MF was defined as >70% increase in tumor SUVmax, and MR as >30% decrease in tumor SUVmax. RESULTS: An MF or MR was identified in 6 of 11 (55%) responders and 0 of 8 (0%) nonresponders, with an objective response rate (ORR) of 100% in the MF-MR group and an ORR of 38% in the stable metabolism (SM) group. An MF or MR was associated with T-cell reinvigoration in the peripheral blood and immune infiltration in the tumor. Overall survival at 3 years was 83% in the MF-MR group and 62% in the SM group. Median progression-free survival (PFS) was >38 months (median not reached) in the MF-MR group and 2.8 months (95% confidence interval, 0.3-5.2) in the SM group (P = 0.017). CONCLUSIONS: Early FDG PET/CT can identify metabolic changes in melanoma metastases that are potentially predictive of response to pembrolizumab and significantly correlated with PFS.

Using CD69 PET Imaging to Monitor Immunotherapy-Induced Immune Activation.

ABSTRACT: Immune checkpoint inhibitors (ICI) have been effective in treating a subset of refractory solid tumors, but only a small percentage of treated patients benefit from these therapies. Thus, there is a clinical need for reliable tools that allow for the early assessment of response to ICIs, as well as a preclinical need for imaging tools that aid in the future development and understanding of immunotherapies. Here we demonstrate that CD69, a canonical early-activation marker expressed on a variety of activated immune cells, including cytotoxic T cells and natural killer (NK) cells, is a promising biomarker for the early assessment of response to immunotherapies. We have developed a PET probe by radiolabeling a highly specific CD69 mAb, H1.2F3, with Zirconium-89 (89Zr), [89Zr]-deferoxamine (DFO)-H1.2F3. [89Zr]-DFO-H1.2F3 detected changes in CD69 expression on primary mouse T cells in vitro and detected activated immune cells in a syngeneic tumor immunotherapy model. In vitro uptake studies with [89Zr]-DFO-H1.2F3 showed a 15-fold increase in CD69 expression for activated primary mouse T cells, relative to untreated resting T cells. In vivo PET imaging showed that tumors of ICI-responsive mice had greater uptake than the tumors of nonresponsive and untreated mice. Ex vivo biodistribution, autoradiography, and IHC analyses supported the PET imaging findings. These data suggest that the CD69 PET imaging approach detects CD69 expression with sufficient sensitivity to quantify immune cell activation in a syngeneic mouse immunotherapy model and could allow for the prediction of therapeutic immune responses to novel immunotherapies.

Spatiotemporal segregation of human marginal zone and memory B cell populations in lymphoid tissue.

Human memory B cells and marginal zone (MZ) B cells share common features such as the expression of CD27 and somatic mutations in their IGHV and BCL6 genes, but the relationship between them is controversial. Here, we show phenotypic progression within lymphoid tissues as MZ B cells emerge from the mature naïve B cell pool via a precursor CD27-CD45RBMEM55+ population distant from memory cells. By imaging mass cytometry, we find that MZ B cells and memory B cells occupy different microanatomical niches in organised gut lymphoid tissues. Both populations disseminate widely between distant lymphoid tissues and blood, and both diversify their IGHV repertoire in gut germinal centres (GC), but nevertheless remain largely clonally separate. MZ B cells are therefore not developmentally contiguous with or analogous to classical memory B cells despite their shared ability to transit through GC, where somatic mutations are acquired.

IgE repertoire and immunological memory: compartmental regulation and antibody function.

It is now generally recognized that bone marrow is the survival niche for antigen-specific plasma cells with long-term immunological memory. These cells release antibodies into the circulation, needed to prime effector cells in the secondary immune response. These antibodies participate in the surveillance for antigen and afford immune defence against pathogens and toxins previously encountered in the primary immune response. IgE antibodies function together with their effector cells, mast cells, to exert 'immediate hypersensitivity' in mucosal tissues at the front line of immune defence. The constant supply of IgE antibodies from bone marrow plasma cells allows the rapid 'recall response' by mast cells upon re-exposure to antigen even after periods of antigen absence. The speed and sensitivity of the IgE recall response and potency of the effector cell functions are advantageous in the early detection and elimination of pathogens and toxins at the sites of attack. Local antigen provocation also stimulates de novo synthesis of IgE or its precursors of other isotypes that undergo IgE switching in the mucosa. This process, however, introduces a delay before mast cells can be sensitized and resume activity; this is terminated shortly after the antigen is eliminated. Recent results from adaptive immune receptor repertoire sequencing of immunoglobulin genes suggest that the mucosal IgE+ plasmablasts, which have undergone affinity maturation in the course of their evolution in vivo, are a source of long-lived IgE+ plasma cells in the bone marrow that are already fully functional.

Chemoradiation after FOLFIRINOX for borderline resectable or locally advanced pancreatic cancer.

BACKGROUND: The safety and efficacy of FOLFIRINOX (FX) followed by consolidative chemoradiation (CRT) in borderline resectable (BRPC) and locally advanced pancreatic cancer (LAPC) has not been extensively studied. We sought to evaluate outcomes and toxicities of this regimen. METHODS: A retrospective review was performed of 33 patients with BRPC or LAPC treated with FX followed by CRT. Radiotherapy was directed at the primary tumor and any involved nodes (84.8% received 50-50.4 Gy with standard fractionation and concurrent capecitabine, while 15.2% of patients received 36 Gy in 15 fractions with weekly gemcitabine). Toxicities of FX and CRT were graded using Common Terminology Criteria for Adverse Events (CTCAE v4.0), and radiographic response was evaluated using Response Evaluation Criteria in Solid Tumors (RECIST). Overall survival (OS), distant metastasis-free survival (DMFS), and local control (LC) were calculated using Kaplan-Meier analyses, and a Cox proportional hazards model was used to assess the impact of clinicopathologic factors on OS. RESULTS: Median follow-up was 19.9 months and patients received a median of 6.4 months of chemotherapy (range, 2.2-12.0 months). There were more T4 tumors than T3 tumors (70% vs. 30%). Grade ≥3 toxicities were low, including fatigue (9.1%), diarrhea (6.1%), neuropathy (6.1%), and dehydration (6.1%). R0 surgical resection was achieved in 5 patients (15.2%) after CRT. Median OS was 22.0 months (91% at 1 year and 45% at 2 years). Median DMFS was 17.8 months (69% at 1 year and 35% at 2 years). LC was 84% at 1 year and 55% at 2 years. CONCLUSIONS: OS is promising with the use of FX in BRPC and LAPC, and consolidative CRT was well tolerated in this cohort. Therefore, the role of radiation after multi-agent chemotherapy should be further evaluated in prospective trials.

A Long-Term Survivor of Metastatic Pancreatic Adenocarcinoma: Free of Recurrence 12 Years After Treatment of Oligometastatic Disease.

Aggressive local therapy for patients with oligometastatic pancreatic ductal adenocarcinoma (PDAC) has traditionally not been pursued due to high rates of distant progression. We describe a 62-year-old male initially presenting with resectable PDAC who underwent the Whipple procedure but developed multiple liver metastases within two months of starting adjuvant gemcitabine. Oxaliplatin was added to the regimen and complete resolution of the liver lesions resulted. He remained disease-free for five years until re-staging revealed a small lung nodule. This was resected and confirmed to be metastatic PDAC. After additional adjuvant gemcitabine, the patient remained free of recurrence for 12 years after diagnosis of metastatic disease and ultimately passed away from complications of ascending cholangitis associated with stricture at the biliary-enteric anastomosis site. He had no evidence of disease recurrence at the time of death. Next-generation sequencing of the tumor was unrevealing, showing only an activating mutation of KRAS and a deleterious mutation of tumor protein p53 (TP53). Our case suggests that while the prognosis for metastatic PDAC is poor, the population is nonetheless heterogeneous. Prognostic biomarkers are needed for the identification of patients for whom aggressive local treatment of oligometastatic PDAC may be warranted.

Antibodies and superantibodies in patients with chronic rhinosinusitis with nasal polyps.

BACKGROUND: Chronic rhinosinusitis with nasal polyps is associated with local immunoglobulin hyperproduction and the presence of IgE antibodies against Staphylococcus aureus enterotoxins (SAEs). Aspirin-exacerbated respiratory disease is a severe form of chronic rhinosinusitis with nasal polyps in which nearly all patients express anti-SAEs. OBJECTIVES: We aimed to understand antibodies reactive to SAEs and determine whether they recognize SAEs through their complementarity-determining regions (CDRs) or framework regions. METHODS: Labeled staphylococcal enterotoxin (SE) A, SED, and SEE were used to isolate single SAE-specific B cells from the nasal polyps of 3 patients with aspirin-exacerbated respiratory disease by using fluorescence-activated cell sorting. Recombinant antibodies with "matched" heavy and light chains were cloned as IgG1, and those of high affinity for specific SAEs, assayed by means of ELISA and surface plasmon resonance, were recloned as IgE and antigen-binding fragments. IgE activities were tested in basophil degranulation assays. RESULTS: Thirty-seven SAE-specific, IgG- or IgA-expressing B cells were isolated and yielded 6 anti-SAE clones, 2 each for SEA, SED, and SEE. Competition binding assays revealed that the anti-SEE antibodies recognize nonoverlapping epitopes in SEE. Unexpectedly, each anti-SEE mediated SEE-induced basophil degranulation, and IgG1 or antigen-binding fragments of each anti-SEE enhanced degranulation by the other anti-SEE. CONCLUSIONS: SEEs can activate basophils by simultaneously binding as antigens in the conventional manner to CDRs and as superantigens to framework regions of anti-SEE IgE in anti-SEE IgE-FcεRI complexes. Anti-SEE IgG1s can enhance the activity of anti-SEE IgEs as conventional antibodies through CDRs or simultaneously as conventional antibodies and as "superantibodies" through CDRs and framework regions to SEEs in SEE-anti-SEE IgE-FcεRI complexes.

Transitional B Cells in Early Human B Cell Development - Time to Revisit the Paradigm?

The B cell repertoire is generated in the adult bone marrow by an ordered series of gene rearrangement processes that result in massive diversity of immunoglobulin (Ig) genes and consequently an equally large number of potential specificities for antigen. As the process is essentially random, the cells exhibiting excess reactivity with self-antigens are generated and need to be removed from the repertoire before the cells are fully mature. Some of the cells are deleted, and some will undergo receptor editing to see if changing the light chain can rescue an autoreactive antibody. As a consequence, the binding properties of the B cell receptor are changed as development progresses through pre-B ≫ immature ≫ transitional ≫ naïve phenotypes. Using long-read, high-throughput, sequencing we have produced a unique set of sequences from these four cell types in human bone marrow and matched peripheral blood, and our results describe the effects of tolerance selection on the B cell repertoire at the Ig gene level. Most strong effects of selection are seen within the heavy chain repertoire and can be seen both in gene usage and in CDRH3 characteristics. Age-related changes are small, and only the size of the CDRH3 shows constant and significant change in these data. The paucity of significant changes in either kappa or lambda light chain repertoires implies that either the heavy chain has more influence over autoreactivity than light chain and/or that switching between kappa and lambda light chains, as opposed to switching within the light chain loci, may effect a more successful autoreactive rescue by receptor editing. Our results show that the transitional cell population contains cells other than those that are part of the pre-B ≫ immature ≫ transitional ≫ naïve development pathway, since the population often shows a repertoire that is outside the trajectory of gene loss/gain between pre-B and naïve stages.

Significant Differences in Physicochemical Properties of Human Immunoglobulin Kappa and Lambda CDR3 Regions.

Antibody variable regions are composed of a heavy and a light chain, and in humans, there are two light chain isotypes: kappa and lambda. Despite their importance in receptor editing, the light chain is often overlooked in the antibody literature, with the focus being on the heavy chain complementarity-determining region (CDR)-H3 region. In this paper, we set out to investigate the physicochemical and structural differences between human kappa and lambda light chain CDR regions. We constructed a dataset containing over 29,000 light chain variable region sequences from IgM-transcribing, newly formed B cells isolated from human bone marrow and peripheral blood. We also used a published human naïve dataset to investigate the CDR-H3 properties of heavy chains paired with kappa and lambda light chains and probed the Protein Data Bank to investigate the structural differences between kappa and lambda antibody CDR regions. We found that kappa and lambda light chains have very different CDR physicochemical and structural properties, whereas the heavy chains with which they are paired do not differ significantly. We also observed that the mean CDR3 N nucleotide addition in the kappa, lambda, and heavy chain gene rearrangements are correlated within donors but can differ between donors. This indicates that terminal deoxynucleotidyl transferase may work with differing efficiencies between different people but the same efficiency in the different classes of immunoglobulin chain within one person. We have observed large differences in the physicochemical and structural properties of kappa and lambda light chain CDR regions. This may reflect different roles in the humoral immune response.

Final analysis of a phase II study of modified FOLFIRINOX in locally advanced and metastatic pancreatic cancer.

BACKGROUND: Modifications of FOLFIRINOX are widely used despite the absence of prospective data validating efficacy in metastatic disease (metastatic pancreatic cancer (MPC)) or locally advanced pancreatic cancer (LAPC). We conducted a multicentre phase II study of modified FOLFIRINOX in advanced pancreatic cancer to assess the impact of dose attenuation in MPC and efficacy in LAPC. METHODS: Patients with untreated MPC or LAPC received modified FOLFIRINOX (irinotecan and bolus 5-fluorouracil reduced by 25%). Adverse events (AEs) were compared with full-dose FOLFIRINOX. Response rate (RR), median progression-free survival (PFS) and median overall survival (OS) were determined. RESULTS: In total, 31 and 44 patients with LAPC and MPC were enrolled, respectively. In MPC, efficacy of modified FOLFIRINOX was comparable with FOLFIRINOX with RR 35.1%, OS 10.2 months (95% CI 7.65-14.32) and PFS 6.1 months (95% CI 5.19-8.31). In LAPC, efficacy was notable with RR 17.2%, resection rate 41.9%, PFS 17.8 months (95% CI 11.0-23.9) and OS 26.6 months (95% CI 16.7, NA). Neutropenia (P<0.0001), vomiting (P<0.001) and fatigue (P=0.01) were significantly decreased. [(18)F]-Fluorodeoxyglucose positron emission tomography imaging response did not correlate with PFS or OS. CONCLUSIONS: In this first prospective study of modified FOLFIRINOX in MPC and LAPC, we observed decreased AEs compared with historical control patients. In MPC, the efficacy appears comparable with FOLFIRINOX. In LAPC, PFS and OS were prolonged and support the continued use of FOLFIRINOX in this setting.

Capecitabine as a Radiosensitizer in Adjuvant Chemoradiotherapy for Pancreatic Cancer: A Retrospective Study.

AIM: Pancreatic cancer remains one of the deadliest cancer diagnoses and is the fourth leading cause of cancer-related deaths in the U.S. Surgery is the mainstay of treatment for the 20% for whom the tumor is resectable, however, controversy exists over the appropriate adjuvant therapy where local recurrence rates remain strikingly high (50-85%). We aimed to evaluate the safety and efficacy of adding capecitabine (a known radiosensitizer by direct and abscopal effects) to concurrent radiation in the adjuvant setting after resection of pancreatic adenocarcinoma. PATIENTS AND METHODS: We conducted a retrospective study of 63 patients diagnosed from 2004-2013 with histopathologically-confirmed stage I/II pancreatic cancer treated with a surgical resection followed by adjuvant concurrent chemoradiation to at least 45 Gy using 3D planning and capecitabine at 1,600 mg/m(2)/day (Monday-Friday) for 6 weeks. This was combined with either 4 months of gemcitabine at 1,000 mg/m(2) weekly for 3 out of 4 weeks or capecitabine at 2,000 mg/m(2) for 14 days every 3 weeks for a total of 4 months. RESULTS: The majority of patients were over 65 years old (71%), male (60%), had negative surgical margins (79%), had pancreatic head or neck involvement (71%), Eastern Cooperative Oncology Group performance score of 1 (71%), and a cancer antigen 19-9 in the range of 11-100 U/ml at the time of diagnosis (51%). Of the 63 patients reviewed, 61 patients (97%) completed concurrent chemoradiotherapy. Treatment was halted in one patient due to gastritis and a second for gastrointestinal bleeding. Otherwise, adverse reactions during concurrent chemoradiotherapy were well-tolerated and the majority were Common Terminology Criteria for Adverse Events grades 1 and 2. Grade 3 toxicity was anorexia (n=2) and hand and foot syndrome (n=2) and GI bleeding (n=1). The only grade 4 toxicities were anorexia (n=1) and fatigue (n=1). The median follow-up of patients at the time of analysis was 36 months. The median survival of the entire cohort was 23.5 (range=8.5-42) months. The 1-, 2- and 3-year survival rates were 80%, 35% and 25%, respectively. CONCLUSION: Concurrent chemoradiation using capecitabine as a radiosensitizer in the adjuvant setting for pancreatic cancer was completed by the vast majority of patients in this series. Treatment was relatively well-tolerated, and its efficacy seems comparable to that for historical controls. This study probably represents the largest yet reported using capecitabine in this setting. Future studies including an increased sample size are required.

Locally advanced unresectable pancreatic cancer.

Twenty-five percent of patients with pancreatic cancer present with locally advanced disease that is unresectable, and the treatment strategy for these patients is controversial, with options including chemotherapy alone, concurrent chemoradiation, or induction chemotherapy followed by chemoradiation. Abstracts presented at the 2014 American Society of Clinical Oncology (ASCO) Annual Meeting (#4001, #4126, and #4024) addressed local control, quality of life, and prognostic factors associated with current regimens of induction chemotherapy and subsequent chemoradiation.

Current strategies in chemoradiation for esophageal cancer.

Chemoradiotherapy (CRT) has an important role in the treatment of esophageal cancer in both the inoperable and the pre-operative settings. Pre-operative chemoradiation therapy is generally given to 41.4-50.4 Gy with platinum or paclitaxel based chemotherapy. The most common definitive dose in the U.S. is 50-50.4 Gy. New advances in CRT for esophageal cancer have come from looking for ways to minimize toxicity and maximize efficacy. Recent investigations for minimizing toxicity have focused advanced radiation techniques such as IMRT and proton therapy, have sought to further define normal tissue tolerances, and have examined the use of tighter fields with less elective clinical target volume coverage. Efforts to maximize efficacy have included the use of early positron emission tomography (PET) response directed therapy, molecularly targeted therapies, and the use of tumor markers that predict response.

Motion management in gastrointestinal cancers.

The presence of tumor and organ motions complicates the planning and delivery of radiotherapy for gastrointestinal cancers. Without proper accounting of the movements, target volume could be under-dosed and the nearby normal critical organs could be over-dosed. This situation is further exacerbated by the close proximity of abdominal tumors to many normal organs at risk (OARs). A number of strategies have been developed to deal with tumor and organ motions in radiotherapy. This article presents a review of the techniques used in the evaluation, quantification, and management of tumor and organ motions for radiotherapy of gastrointestinal cancers.

The effect of a lung cancer care coordination program on timeliness of care.

BACKGROUND: Timeliness of care improves patient satisfaction and might improve outcomes. The CCCP was established in November 2007 to improve timeliness of care of NSCLC at the Veterans Affairs Connecticut Healthcare System (VACHS). PATIENTS AND METHODS: We performed a retrospective cohort analysis of patients diagnosed with NSCLC at VACHS between 2005 and 2010. We compared timeliness of care and stage at diagnosis before and after the implementation of the CCCP. RESULTS: Data from 352 patients were analyzed: 163 with initial abnormal imaging between January 1, 2005 and October 31, 2007, and 189 with imaging conducted between November 1, 2007 and December 31, 2010. Variables associated with a longer interval between the initial abnormal image and the initiation of therapy were: (1) earlier stage (mean of 130 days for stages I/II vs. 87 days for stages III/IV; P < .0001); (2) lack of cancer-related symptoms (145 vs. 60 days; P < .0001); (3) presence of more than 1 medical comorbidity (123 vs. 82; P = .0002); and (4) depression (126 vs. 98 days; P = .029). The percent of patients diagnosed at stages I/II increased from 32% to 48% (P = .006) after establishment of the CCCP. In a multivariate model adjusting for stage, histology, reason for imaging, and presence of primary care provider, implementation of the CCCP resulted in a mean reduction of 25 days between first abnormal image and the initiation of treatment (126 to 101 days; P = .015). CONCLUSION: A centralized, multidisciplinary, hospital-based CCCP can improve timeliness of NSCLC care, and help ensure that early stage lung cancers are diagnosed and treated.

Family-wide investigation of PDZ domain-mediated protein-protein interactions implicates ß-catenin in maintaining the integrity of tight junctions.

ß-catenin is a multifunctional protein that plays a critical role in cell-cell contacts and signal transduction. ß-catenin has previously been shown to interact with PDZ-domain-containing proteins through its C terminus. Using protein microarrays comprising 206 mouse PDZ domains, we identified 26 PDZ-domain-mediated interactions with ß-catenin and confirmed them biochemically and in cellular lysates. Many of the previously unreported interactions involved proteins with annotated roles in tight junctions. We found that four tight-junction-associated PDZ proteins-Scrib, Magi-1, Pard3, and ZO-3-colocalize with ß-catenin at the plasma membrane. Disrupting these interactions by RNA interference, overexpression of PDZ domains, or overexpression of the ß-catenin C terminus altered localization of the full-length proteins, weakened tight junctions, and decreased cellular adhesion. These results suggest that ß-catenin serves as a scaffold to establish the location and function of tight-junction-associated proteins.

A comparison of three treatment strategies for locally advanced and borderline resectable pancreatic cancer.

BACKGROUND: The optimal treatment strategy for locally advanced and borderline resectable pancreatic cancer is not known. We compared overall survival (OS), local control (LC), metastasis free survival (MFS), and percent of patients who were able to undergo successful surgical resection for three treatment strategies. METHODS: We retrospectively reviewed 115 sequentially treated cases of locally advanced (T4) or borderline resectable (T3 but unresectable) pancreatic cancer. Patients were treated with either chemotherapy alone (C), concurrent chemoradiation therapy (CRT), or chemotherapy followed by chemoradiation therapy (CCRT). We compared survival between groups using Kaplan-Meier analysis and Cox-proportional hazards models. RESULTS: Median follow-up was 18.7 months. Fifty-six (49%) patients had locally advanced disease. Of the patients who received chemotherapy up-front, 82/92 (89%) received gemcitabine-based chemotherapy. Of the patients receiving C alone, 11/65 (17%) were diagnosed with distant metastases or died before 3 months. The rate of successful surgical resection was 6/50 (12%) in patients treated with radiation therapy (CRT or CCRT). Median survival times for patients undergoing C, CRT, and CCRT were 13.9, 12.5, and 21.5 months respectively. Patients treated with CCRT experienced statistically significant improved OS and MFS compared to C alone (P=0.003 and P=0.012 respectively). There was no difference in LC between treatment groups. On multivariable analysis younger age (P=0.009), borderline resectable disease (P=0.035), successful surgery (P=0.002), and receiving chemotherapy followed by chemoradiation therapy (P=0.035) were all associated with improved OS. CONCLUSIONS: Treatment with CCRT is associated with improved median OS and MFS compared with C alone. This strategy may select for patients who are less likely to develop early metastases and therefore have a better prognosis.