Locoregional drug delivery for cancer therapy: Preclinical progress and clinical translation

Systemic drug delivery is the current clinically preferred route for cancer therapy. However, challenges associated with tumor localization and off-tumor toxic effects limit the clinical effectiveness of this route. Locoregional drug delivery is an emerging viable alternative to systemic therapies. With the improvement in real-time imaging technologies and tools for direct access to tumor lesions, the clinical applicability of locoregional drug delivery is becoming more prominent. Theoretically, locoregional treatments can bypass challenges faced by systemic drug delivery. Preclinically, locoregional delivery of drugs has demonstrated enhanced therapeutic efficacy with limited off-target effects while still yielding an abscopal effect. Clinically, an array of locoregional strategies is under investigation for the delivery of drugs ranging in target and size. Locoregional tumor treatment strategies can be classified into two main categories: 1) direct drug infusion via injection or implanted port and 2) extended drug elution via injected or implanted depot. The number of studies investigating locoregional drug delivery strategies for cancer treatment is rising exponentially, in both preclinical and clinical settings, with some approaches approved for clinical use. Here, we highlight key preclinical advances and the clinical relevance of such locoregional delivery strategies in the treatment of cancer. Furthermore, we critically analyze 949 clinical trials involving locoregional drug delivery and discuss emerging trends.

Preclinical characterization of macrophage-adhering gadolinium micropatches for MRI contrast after traumatic brain injury in pigs

The choroid plexus (ChP) of the brain plays a central role in orchestrating the recruitment of peripheral leukocytes into the central nervous system (CNS) through the blood-cerebrospinal fluid (BCSF) barrier in pathological conditions, thus offering a unique niche to diagnose CNS disorders. We explored whether magnetic resonance imaging of the ChP could be optimized for mild traumatic brain injury (mTBI). mTBI induces subtle, yet influential, changes in the brain and is currently severely underdiagnosed. We hypothesized that mTBI induces sufficient alterations in the ChP to cause infiltration of circulating leukocytes through the BCSF barrier and developed macrophage-adhering gadolinium [Gd(III)]-loaded anisotropic micropatches (GLAMs), specifically designed to image infiltrating immune cells. GLAMs are hydrogel-based discoidal microparticles that adhere to macrophages without phagocytosis. We present a fabrication process to prepare GLAMs at scale and demonstrate their loading with Gd(III) at high relaxivities, a key indicator of their effectiveness in enhancing image contrast and clarity in medical imaging. In vitro experiments with primary murine and porcine macrophages demonstrated that GLAMs adhere to macrophages also under shear stress and did not affect macrophage viability or functions. Studies in a porcine mTBI model confirmed that intravenously administered macrophage-adhering GLAMs provide a differential signal in the ChP and lateral ventricles at Gd(III) doses 500- to 1000-fold lower than those used in the current clinical standard Gadavist. Under the same mTBI conditions, Gadavist did not offer a differential signal at clinically used doses. Our results suggest that macrophage-adhering GLAMs could facilitate mTBI diagnosis.

Backpack-mediated anti-inflammatory macrophage cell therapy for the treatment of traumatic brain injury

Traumatic brain injury (TBI) is a debilitating disease with no current therapies outside of acute clinical management. While acute, controlled inflammation is important for debris clearance and regeneration after injury, chronic, rampant inflammation plays a significant adverse role in the pathophysiology of secondary brain injury. Immune cell therapies hold unique therapeutic potential for inflammation modulation, due to their active sensing and migration abilities. Macrophages are particularly suited for this task, given the role of macrophages and microglia in the dysregulated inflammatory response after TBI. However, maintaining adoptively transferred macrophages in an anti-inflammatory, wound-healing phenotype against the proinflammatory TBI milieu is essential. To achieve this, we developed discoidal microparticles, termed backpacks, encapsulating anti-inflammatory interleukin-4, and dexamethasone for ex vivo macrophage attachment. Backpacks durably adhered to the surface of macrophages without internalization and maintained an anti-inflammatory phenotype of the carrier macrophage through 7 days in vitro. Backpack-macrophage therapy was scaled up and safely infused into piglets in a cortical impact TBI model. Backpack-macrophages migrated to the brain lesion site and reduced proinflammatory activation of microglia in the lesion penumbra of the rostral gyrus of the cortex and decreased serum concentrations of proinflammatory biomarkers. These immunomodulatory effects elicited a 56% decrease in lesion volume. The results reported here demonstrate, to the best of our knowledge, a potential use of a cell therapy intervention for a large animal model of TBI and highlight the potential of macrophage-based therapy. Further investigation is required to elucidate the neuroprotection mechanisms associated with anti-inflammatory macrophage therapy.

A biomimetic chip to assess subcutaneous bioavailability of monoclonal antibodies in humans

Subcutaneous (subQ) injection is a common route for delivering biotherapeutics, wherein pharmacokinetics is largely influenced by drug transport in a complex subQ tissue microenvironment. The selection of good drug candidates with beneficial pharmacokinetics for subQ injections is currently limited by a lack of reliable testing models. To address this limitation, we report here a Subcutaneous Co-Culture Tissue-on-a-chip for Injection Simulation (SubCuTIS). SubCuTIS possesses a 3D coculture tissue architecture, and it allows facile quantitative determination of relevant scale independent drug transport rate constants. SubCuTIS captures key in vivo physiological characteristics of the subQ tissues, and it differentiates the transport behavior of various chemically distinct molecules. We supplemented the transport measurements with theoretical modeling, which identified subtle differences in the local absorption rate constants of seven clinically available mAbs. Accounting for first-order proteolytic catabolism, we established a mathematical framework to assess clinical bioavailability using the local absorption rate constants obtained from SubCuTIS. Taken together, the technology described here broadens the applicability of organs-on-chips as a standardized and easy-to-use device for quantitative analysis of subQ drug transport.

Extracellular matrix degrading enzyme with stroma-targeting peptides enhance the penetration of liposomes into tumors

Various anti-tumor nanomedicines have been developed based on the enhanced permeability and retention effect. However, the dense extracellular matrix (ECM) in tumors remains a major barrier for the delivery and accumulation of nanoparticles into tumors. While ECM-degrading enzymes, such as collagenase, hyaluronidase, and bromelain, have been used to facilitate the accumulation of nanoparticles, serious side effects arising from the current non-tumor-specific delivery methods limit their clinical applications. Here, we report targeted delivery of bromelain into tumor tissues through its covalent attachment to a hyaluronic acid (HA)-peptide conjugate with tumor ECM targeting ability. The ECM targeting peptide, collagen type IV-binding peptide (C4BP), was chosen from six candidate-peptides based on their ability to bind to frozen sections of triple-negative breast cancer, 4T1 tumor ex vivo. The HA- C4BP conjugate showed a significant increase in tumor accumulation in 4T1-bearing mice after intravenous administration compared to unmodified HA. We further demonstrated that the systemic administration of bromelain conjugated C4BP-HA (C4BP-HA-Bro) potentiates the anti-tumor efficacy of liposomal doxorubicin. C4BP-HA-Bro decreased the number and length of collagen fibers and improved the distribution of doxorubicin within the tumor. No infusion reaction was noted after delivery of C4BP-HA-Bro. C4BP-HA thus offers a potential for effective and safe delivery of bromelain for improved intratumoral delivery of therapeutics.

Strategies to improve the EPR effect: A mechanistic perspective and clinical translation

Many efforts have been made to achieve targeted delivery of anticancer drugs to enhance their efficacy and to reduce their adverse effects. These efforts include the development of nanomedicines as they can selectively penetrate through tumor blood vessels through the enhanced permeability and retention (EPR) effect. The EPR effect was first proposed by Maeda and co-workers in 1986, and since then various types of nanoparticles have been developed to take advantage of the phenomenon with regards to drug delivery. However, the EPR effect has been found to be highly variable and thus unreliable due to the complex tumor microenvironment. Various physical and pharmacological strategies have been explored to overcome this challenge. Here, we review key advances and emerging concepts of such EPR-enhancing strategies. Furthermore, we analyze 723 clinical trials of nanoparticles with EPR enhancers and discuss their clinical translation.

ID: 57: PRE-GESTATIONAL DIABETES AND PREECLAMPSIA IN BANGLADESHI PATIENTS: A RETROSPECTIVE STUDY

Objective

Preeclampsia (PreE) is one of considerable public health threat particularly in developing countries globally affecting approximately 8% of all pregnancies. PreE is a pregnancy-specific condition that increases maternal and infant mortality and morbidity, but the etiology remains unknown. Despite numerous basic, clinical, and epidemiologic studies that have been conducted over the past half century, knowledge of the etiology and pathogenesis of preeclampsia remains elusive. It is diagnosed by new onset increased blood pressure and proteinuria during second or third trimester of gestation; key features of the preeclampsia category include a cut-off blood pressure of 140/90 mm Hg or higher and absolute requirement of proteinuria. Approximately 20% of the diabetic pregnant women develop preE. The mechanisms contributing to this effect is not well characterized. In a recent study, we have shown that hyperglycemia impairs cytotrophoblast (CTB) function via stress signaling. Several researchers demonstrate a direct link between preE and diabetes. The objective of the study was to evaluate potential linkage between the risk of developing preE and the presence of diabetes in pregnant patients in Bangladesh.

Methods

This is a cross-sectional study of 351 pregnant women performed to evaluate the prevalence of PreE with respect to different risk factors such as previous pregnancy, presence of Antiphospholipid antibodies, pre-existing diabetes (before this pregnancy), multiple gestation / singleton, family history of preE in first degree relative (mother, sister and daughters; most commonly mother), maternal age of 40 or greater. The study was conducted in selected hospitals of Dhaka city, Bangladesh during December 2013 to December 2015.

Results

The key study findings revealed that the overall rate of development of PreE in Bangladeshi pre-gestational diabetic patients is 22.6 percent. We gave special emphasis on the occurrence of PreE in pre-gestational diabetic patients. Among 351 respondents, 145 Patients (25.5%) with either DM prior to pregnancy or developing gestational diabetes or without diabetes were older (age >35 years) pregnant women (13.1%). Prevalence of PreE is 25.5 (n=145) and 19.6 (n=199) percent among those who developed pre-gestational diabetes and without diabetes prior to pregnancy. Of the respondents 17.2 percent have both systolic and diastolic hypertension those who developed DM prior to this pregnancy and 13 percent among those who does not developed DM prior to this pregnancy. Occurrence of abortion was up to 3 percentage before this pregnancy 45 percentage who developed DM prior to this pregnancy and 35 percent who does not have diabetes among the respondents.

Conclusions

There is an association has been found between the risk of developing preE and the presence of diabetes in pregnant patients in Bangladesh.

Duplicate orders: an unintended consequence of computerized provider/physician order entry (CPOE) implementation: analysis and mitigation strategies

OBJECTIVE

Computerized provider/physician order entry (CPOE) with clinical decision support (CDS) is designed to improve patient safety. However, a number of unintended consequences which include duplicate ordering have been reported. The objective of this time-series study was to characterize duplicate orders and devise strategies to minimize them.

METHODS

Time series design with systematic weekly sampling for 84 weeks. Each week we queried the CPOE database, downloaded all active orders onto a spreadsheet, and highlighted duplicate orders. We noted the following details for each duplicate order: time, order details (e.g. drug, dose, route and frequency), ordering prescriber, including position and role, and whether the orders originated from a single order or from an order set (and the name of the order set). This analysis led to a number of interventions, including changes in: order sets, workflow, prescriber training, pharmacy procedures, and duplicate alerts.

RESULTS

Duplicates were more likely to originate from different prescribers than from same prescribers; and from order sets than from single orders. After interventions, there was an 84.8% decrease in the duplication rate from weeks 1 to 84 and a 94.6% decrease from the highest (1) to the lowest week (75). Currently, we have negligible duplicate orders.

CONCLUSIONS

Duplicate orders can be a significant unintended consequence of CPOE. By analyzing these orders, we were able to devise and implement generalizable strategies that significantly reduced them. The incidence of duplicate orders before CPOE implementation is unknown, and our data originate from a weekly snapshot of active orders, which serves as a sample of total active orders. Thus, it should be noted that this methodology likely under-reports duplicate orders.

Optimizing effectiveness of laser tympanic membrane fenestration in chronic otitis media with effusion. Clinical and technical considerations

OBJECTIVE

To describe the patient, disease and clinical characteristics that optimize the effectiveness of laser tympanic membrane fenestration (LTMF) to treat chronic otitis media with effusion (OME).

SETTING

Four pediatric otolaryngology tertiary referral centers. IRB approved; participation by informed consent.

METHODS

An observational clinical effectiveness trial was conducted in 164 ears (94 children), who had chronic OME. All patients were candidates for insertion of pressure equalization tubes (PETs) but agreed to undergo LTMF instead. Clinical and audiologic follow-up are reported at 90 days after LTMF.

OUTCOME MEASURES

Clinical effectiveness was defined as an effusion free middle ear at otoscopy with A or C1 tympanogram and normal hearing.

RESULTS

At 90 days, 66% of the 95 evaluable ears were effusion free, all with normal hearing. Children younger than 4 years (P<0.04), who had shorter durations of effusion (P<0.009), and who experienced longer duration of fenestration patency (FP) (P<0.009) correlated to improved outcomes.

CONCLUSIONS

The use of LTMF to create 2--3 weeks of middle ear ventilation in patients with chronic OME (middle ear effusion (MEE) for 3 months or greater) is effective in 66% of 95 (58%) of ears evaluable at 90 days follow-up. This study provides basic information needed to optimize the use of LTMF today and enhance research efforts in the future.

Office-based laser assisted tympanic membrane fenestration in adults and children: pilot data to support an alternative to traditional approaches to otitis media

OBJECTIVES

To determine the role of intermediate duration ( approximately 3 weeks) middle ear ventilation using office-based laser assisted tympanic membrane fenestration in resolving an episode of otitis media with effusion in adults and children who otherwise would have been treated with insertion of pressure equalization tubes.

METHODS

A retrospective chart review of 92 patients (162 ears) was conducted to identify the utility and technical challenges associated with laser assisted tympanic membrane fenestration in an office setting. Clinical characteristics reviewed included: age, gender, duration of effusion, season performed, and hearing and health status of middle ear upon healing of the fenestration.

RESULTS

69% of all patients were effusion free upon closure of the fenestration; 68% of those <3 years; 70% of those 3-7 years; and 70% of those 25-80 years. Some episodes recurred and at final follow-up 64% had normal middle ear structure and function (range of follow-up =1-18 months, mean 2.5 months, median 2.0). Shorter duration of effusion pre-fenestration was more often associated with return to normal middle ear structure and function (P<0.01). Season performed, number of previous episodes of otitis media and pre-treatment tympanometry were not predictive of result. No significant complications were observed.

CONCLUSIONS

The use of office-based laser assisted tympanic membrane fenestration is a reasonably safe and effective procedure for the treatment of otitis media in most adults and children. As a minimally invasive otologic procedure, laser assisted tympanic membrane fenestration has great potential to decrease the rates of both antibiotic usage and insertion of ear tubes.

Office-based insertion of pressure equalization tubes: the role of laser-assisted tympanic membrane fenestration

OBJECTIVE

To describe the role of the hand-held otoscope combined with a flashscanner CO2 laser, OtoLAM (ESC/Sharplan, Yokneam, Israel), for pressure equalization tube (PET) insertion in an office setting.

STUDY DESIGN

Prospective, multisite, clinical cohort trial (Institutional Review Board approved; informed consent) in the setting of pediatric otolaryngology outpatient departments at four tertiary care children's hospitals.

METHODS

Selected for the study were 54 patients (96 ears), ages 6 months to 23 years, who met standard indications for PET insertion using cold-knife myringotomy and tube insertion under general anesthesia. PETs were indicated for recurrent otitis media, chronic otitis media with effusion, and eustachian tube dysfunction-all unresponsive to medical therapy. Topical anesthesia was achieved with iontophoresis (n = 1) or topical anesthesia: 8% tetracaine on an Otowick (Xomed Surgical Products, Jacksonville, FL, catalogue No. 400141) against the tympanic membrane for 45 to 180 minutes (n = 53). Laser-assisted tympanic membrane fenestration was performed with the OtoLAM set at single pulse, 2.0- to 2.6-mm spot size, and between 3 and 18 W. Insertion of grommets was accomplished using the otomicroscope and an "alligator" microforceps. Restraints with papoose were used in 79% of children with a mean age of 34.4 months (SD = 60.9 mo). Clinical, parent/patient, and physician satisfaction and comparative cost impact outcomes are described.

RESULTS

All ears but three (3%) underwent successful placement of a PET. Pain was described as "absent" in 39%, "present but tolerable" in 30%, and "severe" in 30% of children at the time of procedure; 5 minutes after the procedure pain was described as "absent" in 75%, "present but tolerable" in 22%, and "severe" in 3%. Tube plugging (3 of 74 available ears; 4%) or persistent otorrhea (1 of 74 ears; 1.4%) occurred infrequently at the 1-month follow-up. Before PET insertion, hearing loss was noted in 66% of cases (mild, 38%; moderate, 22%; and severe, 6%). Mild hearing loss was noted in only 8% and moderate hearing loss in 2% of 47 (50%) of the ears at the 3-month follow-up. Ninety-two percent of parents were highly satisfied with the procedure in preference to PETs in the operating room under general anesthesia, and 97% preferred OtoLAM with PET insertion, rather than further courses of antibiotics; only one parent would rather have had the PET insertion under general anesthesia. Cost savings to health care organizations, particularly payers, and to parents are substantial (32%-48%) and warrant attention. Cost to the physician is manageable only if an appropriate approach to the third party payers results in a substantial increase in reimbursements.

CONCLUSIONS

The data indicate excellent clinical effectiveness, reduced risk, and high parent and physician satisfaction. Strong incentives for physicians to use this technique are in all stakeholders' best interests. These incentives need to evolve as soon as possible for the more widespread acceptance of OtoLAM with PET insertion in an office setting for appropriately selected patients.

Predicting return to work. A long-term follow-up study of railroad workers after low back injuries

STUDY DESIGN

Evaluation of the long-term outcomes of 178 railroad employees with low back injury who had completed a multidisciplinary rehabilitation program.

OBJECTIVES

To study two major areas: 1) outcomes of the rehabilitation program in terms of the patient's improvement in function and rate of return to work and 2) factors that predict long-term retention at work, both at the railroad and elsewhere.

SUMMARY OF BACKGROUND DATA

Several studies have been published examining rehabilitation outcomes of individuals covered under workers' compensation law, but few exist that have examined railroad workers covered by the Federal Employers Liability Act, and few studies exist with follow-up periods longer than 3 years.

METHODS

Physical/medical, self-reported, and employment/financial data were collected on each patient from medical and employment records. Follow-up data regarding employment status were obtained either from the employer or from the patient by telephone interview.

RESULTS

On average, the patients improved in all objective and subjective measures after rehabilitation. Improvements in these measures were not predictive of return to work. At follow-up examination, 89% of the contacted patients were employed--61% still at the rail-road. The employment factors of lost work days and length of employment and the financial factor of wage rate were the most predictive of long-term work status.

CONCLUSIONS

The multidisciplinary program in the current study was found to improve patient physical functioning and reduce pain. However, success in these measures was not predictive of long-term work status, suggesting that other factors have an impact on work status. Clinicians must be aware that employment and financial factors may have a strong influence on return-to-work outcomes.