Results of a single-arm pilot study of 32P microparticles in unresectable locally advanced pancreatic adenocarcinoma with gemcitabine/nab-paclitaxel or FOLFIRINOX chemotherapy

Background

Unresectable locally advanced pancreatic cancer (LAPC) is generally managed with chemotherapy or chemoradiotherapy, but prognosis is poor with a median survival of ∼13 months (or up to 19 months in some studies). We assessed a novel brachytherapy device, using phosphorous-32 (³²P) microparticles, combined with standard-of-care chemotherapy.

Patients and methods

In this international, multicentre, single-arm, open-label pilot study, adult patients with histologically or cytologically proven unresectable LAPC received ³²P microparticles, via endoscopic ultrasound-guided fine-needle implantation, planned for week 4 of 5-fluorouracil, leucovorin, irinotecan and oxaliplatin (FOLFIRINOX) or gemcitabine/nab-paclitaxel chemotherapy, per investigator’s choice. The primary endpoint was safety and tolerability measured using Common Terminology Criteria for Adverse Events version 4.0. The lead efficacy endpoint was local disease control rate at 16 weeks.

Results

Fifty patients were enrolled and received chemotherapy [intention-to-treat (ITT) population]. Forty-two patients received ³²P microparticle implantation [per protocol (PP) population]. A total of 1102 treatment-emergent adverse events (TEAEs) were reported in the ITT/safety population (956 PP), of which 167 (139 PP) were grade ≥3. In the PP population, 41 TEAEs in 16 (38.1%) patients were possibly or probably related to ³²P microparticles or implantation procedure, including 8 grade ≥3 in 3 (7.1%) patients, compared with 609 TEAEs in 42 (100%) patients attributed to chemotherapy, including 67 grade ≥3 in 28 patients (66.7%). The local disease control rate at 16 weeks was 82.0% (95% confidence interval: 68.6% to 90.9%) (ITT) and 90.5% (95% confidence interval: 77.4% to 97.3%) (PP). Tumour volume, carbohydrate antigen 19-9 levels, and metabolic tumour response at week 12 improved significantly. Ten patients (20.0% ITT; 23.8% PP) had surgical resection and median overall survival was 15.2 and 15.5 months for ITT and PP populations, respectively.

Conclusions

Endoscopic ultrasound-guided ³²P microparticle implantation has an acceptable safety profile. This study also suggests clinically relevant benefits of combining ³²P microparticles with standard-of-care systemic chemotherapy for patients with unresectable LAPC.

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PanCO is the first prospective study of intratumoural ³²P microparticles for locally advanced pancreatic cancer (LAPC).

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This single-arm study assessed a novel brachytherapy (³²P microparticles) combined with standard-of-care chemotherapy.

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Treatment-emergent adverse events attributable to ³²P microparticle implantation were relatively infrequent.

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Local disease control rate at 16 weeks (82%) and resection rate (20%) suggest a clinical benefit of ³²P microparticles.

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The results suggest that ³²P microparticles may address a significant unmet need in patients with unresectable LAPC.

How do machine learning algorithms perform in predicting hospital choices? evidence from changing environments

Researchers have found that machine learning methods are typically better at prediction than econometric models when the choice environment is stable. We study hospital demand models, and evaluate the relative performance of machine learning algorithms when the choice environment changes substantially due to natural disasters that closed previously available hospitals. While machine learning algorithms outperform traditional econometric models in prediction, the gain they provide shrinks when patients' choice sets are more profoundly affected. We show that traditional econometric methods provide important additional information when there are major changes in the choice environment.

Pharmaceutical protein solids: Drying technology, solid-state characterization and stability

Despite the boom in biologics over the past decade, the intrinsic instability of these large molecules poses significant challenges to formulation development. Almost half of all pharmaceutical protein products are formulated in the solid form to preserve protein native structure and extend product shelf-life. In this review, both traditional and emerging drying techniques for producing protein solids will be discussed. During the drying process, various stresses can impact the stability of protein solids. However, understanding the impact of stress on protein product quality can be challenging due to the lack of reliable characterization techniques for biological solids. Both conventional and advanced characterization techniques are discussed including differential scanning calorimetry (DSC), solid-state Fourier transform infrared spectrometry (ssFTIR), solid-state fluorescence spectrometry, solid-state hydrogen deuterium exchange (ssHDX), solid-state nuclear magnetic resonance (ssNMR) and solid-state photolytic labeling (ssPL). Advanced characterization tools may offer mechanistic investigations into local structural changes and interactions at higher resolutions. The continuous exploration of new drying techniques, as well as a better understanding of the effects caused by different drying techniques in solid state, would advance the formulation development of biological products with superior quality.

Effects of drying method and excipient on the structure and physical stability of protein solids: Freeze drying vs. spray freeze drying

This study aims to determine the impacts of drying method and excipient on changes in protein structure and physical stability of model protein solids. Protein solids containing one of two model proteins (lysozyme or myoglobin) were produced with or without excipients (sucrose or mannitol) using freeze drying or spray freeze drying (SFD). The protein powders were then characterized using solid-state Fourier transform infrared spectroscopy (ssFTIR), differential scanning calorimetry (DSC), circular dichroism spectrometry (CD), size exclusion chromatography (SEC), BET surface area measurements and solid-state hydrogen deuterium exchange with mass spectrometry (ssHDX-MS). ssFTIR and CD could identify little to no difference in structure of the proteins in the formulation. ssHDX-MS was able to identify the population heterogeneity, which was undetectable by conventional characterization techniques of ssFTIR and CD. ssHDX-MS metrics such as D_max and peak area showed a good correlation with the protein physical instability (loss of the monomeric peak area by size exclusion chromatography) in 90-day stability studies conducted at 40 °C for lysozyme. Higher specific surface area was associated with greater loss in monomer content for myoglobin-mannitol formulations as compared to myoglobin-only formulations. Spray freeze drying seems a viable manufacturing technique for protein solids with appropriate optimization of formulations. The differences observed within the formulations and between the processes using ssHDX-MS, BET surface area measurements and SEC in this study provide an insight into the influence of drying methods and excipients on protein physical stability.

Effects of drying method and excipient on structure and stability of protein solids using solid-state hydrogen/deuterium exchange mass spectrometry (ssHDX-MS)

Powders containing one of four model proteins (myoglobin, bovine serum albumin, lysozyme, β-lactoglobulin) were formulated with either sucrose, trehalose, or mannitol and dried using lyophilization or spray-drying. The powders were characterized using solid-state Fourier transform infrared spectroscopy (ssFTIR), solid-state fluorescence spectroscopy, differential scanning calorimetry (DSC) and solid-state hydrogen/deuterium exchange mass spectrometry (ssHDX-MS). ssFTIR and fluorescence spectroscopy identified minor structural differences among powders with different excipients and drying methods for some proteins. Using ssHDX-MS, differences in protein structure were observed among protein formulations containing sucrose or trehalose and mannitol, and/or with varying processing conditions, including proteins like β-lactoglobulin, for which standard characterization techniques showed no differences. Proteins processed by spray-drying typically showed greater heterogeneity by ssHDX-MS than those lyophilized; these differences were not detected by ssFTIR or solid-state fluorescence spectroscopy. The ssHDX-MS metrics were better correlated with protein physical instability measured by size-exclusion chromatography in 90-day stability studies (40 °C, 33% RH) than with the results of DSC, ssFTIR, or fluorescence spectroscopy. Thus, ssHDX-MS detected subtle changes in conformation and/or matrix interactions for these proteins that were correlated with storage stability, suggesting that the method can be used to design robust solid-state pharmaceutical protein products more rapidly.

Prices for Medical Services Vary Within Hospitals, but Vary More Across Them

Using commercial claims for 2012-2013 from the Colorado All Payer Claims Database, we examine how medical service prices vary for five hospital-based procedures and the complexity-adjusted inpatient price. We find that prices vary substantially in multiple dimensions. Our analysis indicates that there is significant price variation across payers for the same service in the same hospital. If prices converged to the lowest rate each hospital receives, commercial expenditures would fall by 10% to 20%. Differences across hospitals account for an even more substantial amount of the overall variation. For five out of six prices, we find that differences associated just with hospitals' metropolitan areas account for over 35% of the total variation. We observe substantial residual variation (18%-32%) after accounting for factors specific to a given payer or provider.

Physician Market Structure, Patient Outcomes, and Spending: An Examination of Medicare Beneficiaries

OBJECTIVE

To understand the impact of changes in physician market structure on clinical outcomes and health care utilization.

DATA SOURCES

2005-2012 Medicare fee-for-service claims and enrollment data.

STUDY DESIGN

We consider the effect of cardiology market structure on utilization and health outcomes for four patient populations. We estimate the risk-adjusted impact of competition using multivariate regression models.

PRINCIPAL FINDINGS

The study finds that an increase in consolidation leads to statistically and economically significant increases in negative health outcomes. For example, we find that moving from a zip code at the 25th percentile of cardiology market concentration to one at the 75th percentile would be associated with 5 to 7 percent increases in risk-adjusted mortality for three of the sample populations. We also found higher expenditures in more concentrated markets. For example, moving from a zip code at the 25th percentile of cardiology market concentration to one at the 75th would be associated with 7 to 11 percent increases in expenditures, depending on sample population.

CONCLUSIONS

Our estimates indicate that increases in cardiology market concentration are associated with worse health outcomes and higher health care expenditures. Some effects may be attributed to vertical as well as horizontal changes.

How vertical integration affects the quantity and cost of care for Medicare beneficiaries

Health systems are employing physicians in growing numbers. The implications of this trend are poorly understood and controversial. We use rich data from the Centers for Medicare and Medicaid Services to examine the effects of a set of physician acquisitions by hospital systems on outpatient utilization and spending. We find that financial integration systematically produces economically large changes in the acquired physicians' behavior, but has less consistent effects at the acquiring system level.

For-profit status and industry evolution in health care markets: evidence from the dialysis industry

This paper examines why for-profit dialysis providers have displaced non-profit providers over the last 25 years. Using detailed data on individual markets' evolutions, I find that for-profit facilities were quicker to enter growing markets and slower to exit declining ones than non-profit facilities. Moreover, for-profit providers' presence in a market had a larger impact on the exit and entry behavior of competitors. These results suggest that for-profit dialysis providers have an advantage in static competition relative to non-profit providers, and that this-rather than lower entry costs-explains their increasing prominence. Additional empirical analyses indicate that for-profits' advantage cannot solely be attributed to efficiencies related to membership in a large, multi-facility chain. This further suggests that managerial incentives have had an economically significant impact on long-run market structure in this industry.

Sexual narcissism: a validation study

Sexual narcissism, an egocentric pattern of sexual behavior, has recently been described in the literature and has been discovered to be associated with cluster B type personality disorders. Although the research seems to have validated sexual narcissism as a characteristic of borderline and histrionic personality disorders, it is yet to be tested with narcissistic personalities. In an effort to further explore this relationship as well as the validity of sexual narcissism, this study systematically compared a sample (ages 24-33 years) of males with narcissistic personality disorder with an adequately matched sample of males without personality disorders. As compared to the control group, narcissistic men were found to have significantly lower self-esteem, more negative attitudes toward sex, greater egocentric patterns of sexual behavior, more conservative or traditional gender-role orientation, and greater sexual preoccupation. Despite these findings, there were no significant differences between the groups on sexual depression and the narcissistic men evidenced significantly higher sexual esteem. Implications for these findings are discussed.

A pharmacological evaluation of the pull-up test for muscle relaxation in rats

The pull-up test for muscle relaxation is described and validated. At testing, rats were evaluated for their ability to recover ('pull-up') from a fully inverted head-down position. Control animals rapidly regained position (median: 1 s). Known muscle relaxants increased latency to pull-up compared to controls. The test proved sensitive to the effects of barbiturates and benzodiazepines which produced graded dose-response functions. In general, results in the pull-up test corresponded with known potencies, with weaker muscle relaxants such as clobazam and oxazepam being less active. The test was relatively insensitive to non-benzodiazepine compounds (e.g., haloperidol, etomidate, morphine, fentanyl and risperidone) producing cataleptic, catatonic, neuroleptic, analgesic, sedative or hypnotic effects. In terms of ED50 values for barbiturates and benzodiazepines, the pull-up test correlated significantly with ED50s from the rotarod test, the antipentylenetetrazol test, ataxia in rats and muscle relaxation in cats. It was concluded that the pull-up test was relatively specific for muscle relaxation and provided a simple alternative to more time-consuming or equipment-intensive tests.

Direct evidence for mediation of an anticonflict effect of baclofen by GABAb receptors

The present article reports an experiment on the effects of baclofen (0, 0.5, 1.0, and 2.0 mg/kg) on punished drinking in rats and the modification of these by delta-amino-n-valeric acid (DANVA) (0 and 10.0 mg/kg). Baclofen significantly enhanced punished drinking and this increase was abolished by DANVA, which had no intrinsic anxiogenic activity. It is concluded that GABAb receptors probably mediate this effect of baclofen and that such receptors may be a potential site of anxiolytic drug action.

Thermal homeostasis in pregnant rats during heat stress

Rats exposed to inescapable heat stress maintained a controlled hyperthermia while increasing heat loss by cutaneous vasodilatation and by grooming behavior. In nonpregnant rats, the evaporation of saliva groomed onto the body surfaces increased exponentially as a function of ambient temperature above 36 degrees C. This was associated with a decrease in the body temperature threshold for salivary secretion from the submaxillary gland, which then began at approximately the same body temperature as cutaneous vasodilatation. In addition, the pregnant rats maintained a lower level of controlled hyperthermia during heat stress than did nonpregnant rats. This appeared to result from a decreased production of metabolic heat, reduced insulation on the ventral surface, and an increased motivation to keep cool during heat stress. These changes met the increased need for thermolysis during pregnancy and provided for thermal homeostasis both in the pregnant rat and in the unborn fetuses.

Spontaneous recovery from nondepolarizing neuromuscular blockade: correlation between clinical and evoked responses

The effects of nondepolarizing muscle relaxants were allowed to wear off spontaneously in 10 ASA class III and IV patients following major surgery. Neuromuscular and respiratory function were followed by clinical testing and by evoked muscle responses using a train of 4 (TOF) supramaximal stimuli. At a TOF of 70 percent (range 62 to 78%), all patients sustained eye-opening, hand-grasp, and tongue-protrusion, while 9/10 sustained head-lift. Vital capacity (VC) averaged 17 ml/kg when the TOF reached 70 percent. The increase in VC correlated with the increase in TOF (r = 0.88). There was no correlation between inspiratory force (IF) and TOF, but all patients achieved an IF equal to or greater than -22 cm H2O at 70 percent. Thus, TOF correlates well with clinical signs of neuromuscular and respiratory recovery in this group of patients and complements earlier studies in healthy anesthetized patients and nonmedicated volunteers.

Radioimmunoassay of antidiuretic hormone during morphine anaesthesia

The effect of morphine anaesthesia on plasma antidiuretic hormone levels was studied in seven adult patients. Measurements of ADH showed no significant change with morphine and 50 per cent nitrous oxide. Significant elevation occurred with surgical stimulation as previously reported. Changes in urine flow with high doses of morphine are then not ADH related.