Risk factors for hospitalisation and associated costs among patients with hepatitis A associated with imported pomegranate arils, United States, 2013

OBJECTIVES

To assess hospitalisation risk factors and economic effects associated with a multistate hepatitis A outbreak in 2013.

STUDY DESIGN

Retrospective case series.

METHODS

Eligible outbreak-related cases confirmed by September 1, 2013, were defined as acute hepatitis symptoms and positive IgM anti-hepatitis A during March 15-August 12 among patients who consumed the food vehicle or had the outbreak genotype. We reviewed medical records, comparing demographic and clinical characteristics among hospitalized and non-hospitalized patients; we used logistic regression analysis to identify factors associated with hospitalization. We interviewed patients regarding symptom duration and healthcare usage and estimated per-patient and total costs. Health departments reported outbreak-related personnel hours.

RESULTS

Medical records were reviewed for 147/159 (92%) eligible patients; median age was 48 (range: 1-84) years, and 64 (44%) patients were hospitalized. Having any chronic medical condition was independently associated with hospitalisation (odds ratio, 3.80; 95% confidence interval, 1.68-8.62). Interviews were completed for 114 (72%) eligible patients; estimated per-patient cost of healthcare and productivity loss was $13,467 for hospitalized and $2138 for non-hospitalized patients and $1,304,648 for all 165 outbreak-related cases. State and local public health personnel expenditures included 82 h and $3221/outbreak-related case.

CONCLUSIONS

Hospitalisations in this outbreak were associated with chronic medical conditions and resulted in substantial healthcare usage and lost productivity. These data can be used to inform future evaluation of expansion of hepatitis A vaccination recommendations to include adults with chronic medical conditions.

Genetic aberrations in multiple myeloma characterized by cIg-FISH: a Brazilian context

Genetic abnormalities are critical prognostic factors for patients diagnosed with multiple myeloma (MM). This retrospective, multicenter study aimed to contribute with the genetic and clinical characterization of MM patients in a country with continental dimensions such as Brazil. Genetic abnormalities were assessed by cIg-fluorescent in situ hybridization (cIg-FISH) in a series of 152 MM patients (median age 55 years, 58.5% men). Overall, genetic abnormalities were detected in 52.7% (80/152) of patients. A 14q32 rearrangement was detected in 33.5% (n=51), including t(11;14), t(4;14) and t(14;16) in 18.4, 14.1, and 1% of cases, respectively. del(13q) was identified in 42.7% (n=65) of patients, of whom 49.2% (32/65) presented a concomitant 14q32 rearrangement. del(17p) had a frequency of 5.2% (n=8). del(13q) was associated with high plasma cell burden (≥50%, P=0.02), and del(17p) with advanced ISS stages (P=0.05) and extramedullary disease (P=0.03). t(4;14) was associated with advanced Durie-Salmon stages (P=0.008), renal insufficiency (P=0.01) and was more common in patients over 60 years old. This study reports similar frequencies of genetic abnormalities to most series worldwide, whereas the t(14;16) and del(17p), two high risk factors for newly diagnosed patients, exhibited lower frequencies. Our results expand the knowledge on the molecular features of MM in Brazil, a country where innovative therapies that could overcome a poor prognosis for some genetic abnormalities are not always available.

New Life for Immunotoxin Cancer Therapy

Immunotoxins are targeted anticancer therapeutics that kill cancer cells using a cytotoxic bacterial toxin payload. Their development for use in solid tumor malignancies was delayed due to issues with their immunogenicity and limited therapeutic window. However, new research has rejuvenated the field. Coadministration with a lymphocyte-depleting regimen of pentostatin and cyclophosphamide can delay antidrug antibody formation, increasing the number of treatment cycles that patients can receive and resulting in durable responses in heavily pretreated patients. In addition, a new generation of immunotoxin molecules with reduced immunogenicity and nonspecific toxicity has been developed through protein engineering techniques, and one has recently entered the clinic. In preclinical studies in mouse models, these new agents are effective against many tumor types as single agents, and also produce synergistic antitumor responses in combination with chemotherapy. These new immunotoxins have renewed excitement in the field and may prove a promising addition to the targeted therapy repertoire.

High mesothelin expression in advanced lung adenocarcinoma is associated with KRAS mutations and a poor prognosis

Mesothelin is a cell surface glycoprotein which is highly expressed in several epithelial cancers and may have a role in cell adhesion and metastases. In this study, we used prospectively obtained clinical and pathological data to characterize mesothelin expression in advanced lung adenocarcinoma. Tissue was obtained from patients who underwent molecular profiling of potentially actionable genes on a trial of molecular profiling and targeted therapies in advanced thoracic malignancies. We immunohistochemically evaluated the intensity, and the percentage of cells expressing mesothelin in 93 advanced lung adenocarcinomas. The evaluation was blinded for molecular data and outcome. Mutations of EGFR, KRAS, BRAF, AKT1, PIK3CA and HER2 were assessed by pyrosequencing; HER2 amplification and ALK translocation were assessed by fluorescence in situ hybridization. 53% of advanced lung adenocarcinomas expressed mesothelin to some degree; high mesothelin expression, defined as mesothelin positivity in more than 25% of cells, was found in 24% of patients. High mesothelin expression was associated with inferior survival (median 18.2 months vs. 32.9 months; P = 0.014). High mesothelin expression was strongly associated with mutant KRAS (P < 0.0001) and wild-type EGFR (P = 0.002). Our results provide strong rationale to explore anti-mesothelin targeted therapies in advanced lung adenocarcinoma especially in the KRAS-mutant subgroup.

Safety and biodistribution of 111In-amatuximab in patients with mesothelin expressing cancers using single photon emission computed tomography-computed tomography (SPECT-CT) imaging

Amatuximab is a chimeric high-affinity monoclonal IgG1/k antibody targeting mesothelin that is being developed for treatment of mesothelin-expressing cancers. Considering the ongoing clinical development of amatuximab in these cancers, our objective was to characterize the biodistribution, and dosimetry of ¹¹¹Indium (¹¹¹In) radiolabelled amatuximab in mesothelin-expressing cancers. Between October 2011 and February 2013, six patients including four with malignant mesothelioma and two with pancreatic adenocarcinoma underwent Single Photon Emission Computed Tomography-Computed Tomography (SPECT/CT) imaging following administration of ¹¹¹In amatuximab. SPECT/CT images were obtained at 2–4 hours, 24–48 hours and 96–168 hours after radiotracer injection. In all patients, tumor to background ratios (TBR) consistently met or exceeded an uptake of 1.2 (range 1.2–62.0) which is considered the minimum TBR that can be visualized. TBRs were higher in tumors of patients with mesothelioma than pancreatic adenocarcinoma. ¹¹¹In-amatuximab uptake was noted in both primary tumors and metastatic sites. The radiotracer dose was generally well-tolerated and demonstrated physiologic uptake in the heart, liver, kidneys and spleen. This is the first study to show tumor localization of an anti-mesothelin antibody in humans. Our results show that ¹¹¹In-amatuximab was well tolerated with a favorable dosimetry profile. It localizes to mesothelin expressing cancers with a higher uptake in mesothelioma than pancreatic cancer.

Recombinant Immunotoxin with T-cell Epitope Mutations That Greatly Reduce Immunogenicity for Treatment of Mesothelin-Expressing Tumors

SS1P is a recombinant immunotoxin (RIT) that targets mesothelin. It consists of an antimesothelin Fv fused to a portion of Pseudomonas exotoxin A. In clinical studies, it has produced dramatic responses in patients with advanced mesothelioma, when combined with immunosuppressive therapy so that several treatment cycles could be given. Otherwise its activity is limited by its immunogenicity. In this work, we describe the development and characterization of LMB-T20, a highly potent RIT targeted at mesothelin-expressing cancers with low immunogenicity due to removal of its eight T-cell epitopes. LMB-T20 was more active than SS1P when tested on four different mesothelin-expressing cell lines as well as on cells obtained from patients with mesothelioma. It also has potent antitumor activity in mice, and has reduced immunogenicity as measured by cytokine secretion assays. In conclusion, LMB-T20 is a favorable candidate for evaluation in clinical trials due to its reduced immunogenicity and excellent activity.

New high affinity monoclonal antibodies recognize non-overlapping epitopes on mesothelin for monitoring and treating mesothelioma

Mesothelin is an emerging cell surface target in mesothelioma and other solid tumors. Most antibody drug candidates recognize highly immunogenic Region I (296–390) on mesothelin. Here, we report a group of high-affinity non-Region I rabbit monoclonal antibodies. These antibodies do not compete for mesothelin binding with the immunotoxin SS1P that binds Region I of mesothelin. One pair of antibodies (YP218 and YP223) is suitable to detect soluble mesothelin in a sandwich ELISA with high sensitivity. The new assay can also be used to measure serum mesothelin concentration in mesothelioma patients, indicating its potential use for monitoring patients treated with current antibody therapies targeting Region I. The antibodies are highly specific and sensitive in immunostaining of mesothelioma. To explore their use in tumor therapy, we have generated the immunotoxins based on the Fv of these antibodies. One immunotoxin (YP218 Fv-PE38) exhibits potent anti-tumor cytotoxicity towards primary mesothelioma cell lines in vitro and an NCI-H226 xenograft tumor in mice. Furthermore, we have engineered a humanized YP218 Fv that retains full binding affinity for mesothelin-expressing cancer cells. In conclusion, with their unique binding properties, these antibodies may be promising candidates for monitoring and treating mesothelioma and other mesothelin-expressing cancers.

Mesothelioma patient derived tumor xenografts with defined BAP1 mutations that mimic the molecular characteristics of human malignant mesothelioma

Background

The development and evaluation of new therapeutic approaches for malignant mesothelioma has been sparse due, in part, to lack of suitable tumor models.

Methods

We established primary mesothelioma cultures from pleural and ascitic fluids of five patients with advanced mesothelioma. Electron microscopy and immunohistochemistry (IHC) confirmed their mesothelial origin. Patient derived xenografts were generated by injecting the cells in nude or SCID mice, and malignant potential of the cells was analyzed by soft agar colony assay. Molecular profiles of the primary patient tumors, early passage cell cultures, and patient derived xenografts were assessed using mutational analysis, fluorescence in situ hybridization (FISH) analysis and IHC.

Results

Primary cultures from all five tumors exhibited morphologic and IHC features consistent to those of mesothelioma cells. Mutations of BAP1 and CDKN2A were each detected in four tumors. BAP1 mutation was associated with the lack of expression of BAP1 protein. Three cell cultures, all of which were derived from BAP1 mutant primary tumors, exhibited anchorage independent growth and also formed tumors in mice, suggesting that BAP1 loss may enhance tumor growth in vivo. Both early passage cell cultures and mouse xenograft tumors harbored BAP1 mutations and CDKN2A deletions identical to those found in the corresponding primary patient tumors.

Conclusions

The mesothelioma patient derived tumor xenografts with mutational alterations that mimic those observed in patient tumors which we established can be used for preclinical development of novel drug regimens and for studying the functional aspects of BAP1 biology in mesothelioma.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1362-2) contains supplementary material, which is available to authorized users.

Advances in anticancer immunotoxin therapy

Immunotoxins are a novel class of antibody-conjugated therapeutics currently in clinical development for a variety of malignancies. They consist of an antibody-based targeting domain fused to a bacterial toxin payload for cell killing. Immunotoxins kill cells by inhibiting protein synthesis, a unique mechanism of action that is toxic to both dividing and nondividing cells. Recent advances in the design and administration of immunotoxins are overcoming historical challenges in the field, leading to renewed interest in these therapeutics.

Phase 1 study of the antimesothelin immunotoxin SS1P in combination with pemetrexed and cisplatin for front-line therapy of pleural mesothelioma and correlation of tumor response with serum mesothelin, megakaryocyte potentiating factor, and cancer antigen 125

BACKGROUND

The primary objective of this study was to determine the safety and maximum tolerated dose (MTD) of the antimesothelin immunotoxin SS1(dsFv)PE38 (SS1P) (a recombinant antimesothelin immunotoxin consisting of a murine antimesothelin variable antibody fragment [Fv] linked to PE38, a truncated portion of Pseudomonas exotoxin A) in combination with pemetrexed and cisplatin in chemotherapy-naive patients with advanced malignant pleural mesothelioma (MPM). Secondary objectives included tumor response, SS1P pharmacokinetics, and serum biomarkers of response.

METHODS

Chemotherapy-naive patients with stage III or IV, unresectable, epithelial or biphasic MPM and normal organ functions were eligible. Pemetrexed (500 mg/m(2) on day 1) and cisplatin (75 mg/m(2) on day 1) were administered every 3 weeks for up to 6 cycles with escalating doses of SS1P administered intravenously on days 1, 3, and 5 during cycles 1 and 2. Tumor response was evaluated every 6 weeks.

RESULTS

Twenty-four patients received SS1P at 4 dose levels from 25 to 55 mcg/kg. Grade 3 fatigue was dose-limiting in 1 patient at 55 mcg/kg. The MTD of SS1P was established as 45 mcg/kg. Other grade 3 toxicities associated with SS1P included hypoalbuminemia (21%), back pain (13%), and hypotension (8%). Of 20 evaluable patients, 12 (60%) had a partial response, 3 had stable disease, and 5 had progressive disease. Of 13 patients who received the MTD, 10 (77%) had a partial response, 1 had stable disease, and 2 had progressive disease. Objective radiologic responses were associated with significant decreases in serum mesothelin (P=.0030), megakaryocyte potentiating factor (P=.0005), and cancer antigen 125 (P < .0001).

CONCLUSIONS

SS1P given with pemetrexed and cisplatin is safe and well tolerated and exhibits significant antitumor activity in patients with unresectable, advanced pleural mesothelioma. Serum mesothelin, megakaryocyte potentiating factor, and cancer antigen 125 levels correlated with objective tumor responses.

Phase II clinical trial of amatuximab, a chimeric antimesothelin antibody with pemetrexed and cisplatin in advanced unresectable pleural mesothelioma

PURPOSE

Amatuximab is a chimeric monoclonal antibody to mesothelin, a cell surface glycoprotein highly expressed in malignant pleural mesothelioma (MPM). On the basis of its synergy with chemotherapy in preclinical studies, we evaluated the antitumor activity of amatuximab plus pemetrexed and cisplatin in patients with unresectable MPM.

EXPERIMENTAL DESIGN

In a single-arm phase II study, amatuximab (5 mg/kg) was administered on days 1 and 8 with pemetrexed (500 mg/m(2)) and cisplatin (75 mg/m(2)) on day 1 of 21-day cycles for up to six cycles. Patients with response or stable disease received amatuximab maintenance until disease progression. Primary endpoint was progression-free survival (PFS) at 6 months. Secondary endpoints were overall survival (OS), response rate, and safety.

RESULTS

Eighty-nine patients were enrolled at 26 centers. Median of five cycles (range, 1-6) of combination treatment was administered, and 56 (63%) patients received amatuximab maintenance. Combination therapy resulted in no overlapping toxicities. Eleven patients (12.4%) had amatuximab-related hypersensitivity reactions. Responses included partial responses in 33 (40%) and stable disease in 42 (51%). Six-month PFS rate was 51% [95% confidence interval (CI), 39.1-62.3)], median PFS was 6.1 months (95% CI, 5.8-6.4), and median OS was 14.8 months (95% CI, 12.4-18.5) with 29 patients alive at data cut-off.

CONCLUSIONS

Amatuximab with pemetrexed and cisplatin was well tolerated with objective tumor response or stable disease rate of 90% by independent radiologic review. Although PFS was not significantly different from historical controls, the median OS was 14.8 months with a third of patients alive and 5 continuing to receive amatuximab at the time of analysis.

Abdominal cocoon

Background The abdominal cocoon syndrome was first described as a rare condition where part of or the whole small bowel is encased within a fibrous membrane. Idiopathic sclerosing encapsulating peritonitis (or abdominal cocoon) is a rare cause of small bowel obstruction, especially in adult population. Diagnosis is usually incidental at laparotomy. But preoperative diagnosis can be made. Case presentation This report is of a 27-year-old Bangladeshi male who presented with increasing abdominal pain and features of subacute intestinal obstruction. He had a history appendicectomy 2 months back through grid iron incision in a peripheral hospital. Pre-operative work-up did not reveal a sac like structure encasing small intestinal loops. At computed tomography of the abdomen and pelvis, a huge cystic structure was seen encasing loops of small bowel. At laparotomy, a fibrous capsule was revealed, in which small bowel loops were encased, with the presence of interloop adhesions. A diagnosis of primary abdominal cocoon was established and extensive adhesiolysis was performed. The patient had an uneventful recovery and follow-up. No evidence of Kochs noted in the abdomen or on histopathology of tissue sent for examination. Conclusion Abdominal cocoon is a rare cause of small bowel obstruction, but should be suspected especially in cases with attacks of non strangulating obstruction in the same individual. A high index of clinical suspicion may be generated by the recurrent character of small bowel obstruction. Clinicians must rigorously pursue a preoperative diagnosis. The overall prognosis is satisfactory. DOI: http://dx.doi.org/10.3329/pulse.v5i2.20269 Pulse Vol.5 July 2011 p.61-64