A Multicentric, Retrospective, Real-world Study on Immune-related Adverse Events in Patients with Advanced Non-small Cell Lung Cancers Treated with Pembrolizumab Monotherapy

AIMS

We present 7 years of clinical experience with single-agent pembrolizumab immune checkpoint inhibitor immunotherapy in non-small cell lung cancers (NSCLC) from four UK cancer centres.

MATERIALS AND METHODS

This multi-institutional retrospective cohort study included 226 metastatic NSCLC patients. Outcomes were number and severity of immune-related adverse events (irAEs), median progression-free survival (mPFS) and median overall survival (mOS).

RESULTS

Within our cohort, 119/226 (53%) patients developed irAEs. Of these, 54/119 (45%) experienced irAEs affecting two or more organ systems. The most common irAEs were diarrhoea and rash. The development of an irAE was associated with better mOS (20.7 versus 8.0 months; P < 0.001) and mPFS (12.0 versus 3.9 months; P < 0.001). The development of grade 3/4 toxicities was associated with worse outcomes compared with the development of grade 1/2 toxicities (mOS 6.1 months versus 25.2 months, P < 0.01; mPFS 5.6 months versus 19.3 months, P = 0.01, respectively). Females had a higher proportion of reported grade 3/4 toxicities (13/44 [29.5%] versus 10/74 [13.5%], P = 0.03). Using a multiple Cox regression model, the presence of irAEs was associated with a better overall survival (hazard ratio = 0.42, 95% confidence interval 0.29-0.61; P < 0.01) and better PFS (hazard ratio 0.38, 95% confidence interval 0.27-0.53; P < 0.001).

CONCLUSION

In this multicentre retrospective cohort study, the development of at least one irAE was associated with significantly longer mPFS and mOS; however, more severe grade 3 and 4 irAEs were associated with worse outcomes. Delayed-onset irAEs, after the 3-month timepoint, were associated with better clinical outcomes.

A Mathematical Analysis of Clustering-Free Local SAR Compression Algorithms for MRI Safety in Parallel Transmission

Parallel transmission (pTX) is a versatile solution to enable UHF MRI of the human body, where radiofrequency (RF) field inhomogeneity appears very challenging. Today, state of the art monitoring of the local SAR in pTX consists in evaluating the RF power deposition on specific SAR matrices called Virtual Observation Points (VOPs). It essentially relies on accurate electromagnetic simulations able to return the local SAR distribution inside the body in response to any applied pTX RF waveform. In order to reduce the number of SAR matrices to a value compatible with real time SAR monitoring ( << 103) , a VOP set is obtained by partitioning the SAR model into clusters, and associating a so- called dominant SAR matrix to every cluster. More recently, a clustering-free compression method was proposed, allowing for a significant reduction in the number of SAR matrices. The concept and derivation however assumed static RF shims and their extension to dynamic pTX is not straightforward, thereby casting doubt on the strict validity of the compression approach for these more complicated RF waveforms. In this work, we provide the mathematical framework to tackle this problem and find a rigorous justification of this criterion in the light of convex optimization theory. Our analysis led us to a variant of the clustering-free compression approach exploiting convex optimization. This new compression algorithm offers computational gains for large SAR models and for high-channel count pTX RF coils.

Dentin Discoloration and Pulpal Ion Concentrations Following Silver Diamine Fluoride and Potassium Iodide Treatment

OBJECTIVE

The objective of this in vitro study was to evaluate the effects of potassium iodide on dentin discoloration and ion penetration into the pulp chamber after application of silver diamine fluoride (SDF).

METHODS

Proximal surfaces of extracted one-rooted sound human teeth were polished to obtain flat dentin and treated with 17% EDTA for two minutes. Each tooth was then fixed to a test tube. The specimens were distributed into five groups according to the treatment: SDF (Advantage Arrest, Elevate Oral Care); SDF-KI (SSKI, Upsher-Smith); RV-SDF (Riva Star, SDI); and RV-SDFKI. The CIE L*a*b* color value for each proximal dentin was assessed using a colorimeter (CR200, Konica-Minolta) at baseline, after two minutes, 10 minutes, and 24 hours, and ΔE compared to baseline was calculated. Subsequently, the water-filled tube was inverted to collect the ions that had penetrated from the tooth surface into the pulp chamber. Silver, iodide, and fluoride in the pulp were measured using trace element analysis (ISMat) and fluoride ion-selective electrode (Orion, Thermo Scientific) at days 1, 2, 7, and 14.

RESULTS

Dentin in both SDF-KI groups showed no visual change in color whereas the groups using only SDF exhibited gradual staining. The time, the treatment and their interaction had a significant effect on ΔE (p<0.001). The fluoride concentrations at day 1 and day 14 for group SDF and KI were significantly lower compared to SDF (p=0.044). There was a difference between control groups and other groups in silver and iodine (p<0.05), whereas there was no significant difference among groups with treatment after 14 days (p>0.05).

CONCLUSION

The application of KI after SDF treatment could significantly reduce the dentin staining. The pulpal fluoride concentration in the groups using SDF-KI was lower compared to the ones using SDF only, whereas there was no difference observed in iodide and silver among the groups with treatment.

The management of perineal hernia following abdomino-perineal excision for cancer

PURPOSE

Perineal hernia (PH) is a tardive complication following abdomino-perineal resection (APR). Many repair methods are described and evidences are lacking. The aim of this study was to report PH management, analyze surgery outcomes and review the available literature.

METHODS

We retrospectively included all consecutive PH repair after APR performed between 2001 and 2017. We recorded data on APR surgery, PH symptoms and repair, and follow-up (recurrence and morbidity). Literature review included published articles on PubMed between 1960 and 2017.

RESULTS

24 PH repairs were included. The approach was perineal N = 16, abdominal N = 5 and combined N = 3. A biological mesh was used for 17, a synthetic for 5 and a flap for 2 patients. The median follow-up was 25 months. Overall morbidity was 37.5% (N = 9): 37.5% for the perineal, 20% for the abdominal, and 66.7% for the combined approach. Complications occurred in 35.3% of biological and 20% of synthetic mesh repairs. Recurrence rate was 41.7%, similar for biological (n = 8, 47.1%) and synthetic meshs (n = 2; 40%). No recurrence occurred in the flap group. Depending of the approach, we found 50% for perineal (n = 8) and 40% of the abdominal cohort (N = 2). Among twelve studies, recurrence rates ranged from 0 to 66.7%. Abdominal or laparoscopic approach with synthetic mesh was associated with less recurrences (0 and 12.5% respectively) and complications (37.5% and 9.5%).

CONCLUSIONS

Recurrences following PH repair are high irrespective of the repair technique. More studies are necessary to identify PH risk factors and decide the appropriate perineal reconstruction.

Signal-domain optimization metrics for MPRAGE RF pulse design in parallel transmission at 7 tesla

PURPOSE

Standard radiofrequency pulse design strategies focus on minimizing the deviation of the flip angle from a target value, which is sufficient but not necessary for signal homogeneity. An alternative approach, based directly on the signal, here is proposed for the MPRAGE sequence, and is developed in the parallel transmission framework with the use of the k_T -points parametrization.

METHODS

The flip angle-homogenizing and the proposed methods were investigated numerically under explicit power and specific absorption rate constraints and tested experimentally in vivo on a 7 T parallel transmission system enabling real time local specific absorption rate monitoring. Radiofrequency pulse performance was assessed by a careful analysis of the signal and contrast between white and gray matter.

RESULTS

Despite a slight reduction of the flip angle uniformity, an improved signal and contrast homogeneity with a significant reduction of the specific absorption rate was achieved with the proposed metric in comparison with standard pulse designs.

CONCLUSION

The proposed joint optimization of the inversion and excitation pulses enables significant reduction of the specific absorption rate in the MPRAGE sequence while preserving image quality. The work reported thus unveils a possible direction to increase the potential of ultra-high field MRI and parallel transmission. Magn Reson Med 76:1431-1442, 2016. © 2015 International Society for Magnetic Resonance in Medicine.

Parallel-transmission-enabled magnetization-prepared rapid gradient-echo T1-weighted imaging of the human brain at 7 T

One of the promises of Ultra High Field (UHF) MRI scanners is to bring finer spatial resolution in the human brain images due to an increased signal to noise ratio. However, at such field strengths, the spatial non-uniformity of the Radio Frequency (RF) transmit profiles challenges the applicability of most MRI sequences, where the signal and contrast levels strongly depend on the flip angle (FA) homogeneity. In particular, the MP-RAGE sequence, one of the most commonly employed 3D sequences to obtain T1-weighted anatomical images of the brain, is highly sensitive to these spatial variations. These cause deterioration in image quality and complicate subsequent image post-processing such as automated tissue segmentation at UHF. In this work, we evaluate the potential of parallel-transmission (pTx) to obtain high-quality MP-RAGE images of the human brain at 7 T. To this end, non-selective transmit-SENSE pulses were individually tailored for each of 8 subjects under study, and applied to an 8-channel transmit-array. Such RF pulses were designed both for the low-FA excitation train and the 180° inversion preparation involved in the sequence, both utilizing the recently introduced k(T)-point trajectory. The resulting images were compared with those obtained from the conventional method and from subject-specific RF-shimmed excitations. In addition, four of the volunteers were scanned at 3 T for benchmarking purposes (clinical setup without pTx). Subsequently, automated tissue classification was performed to provide a more quantitative measure of the final image quality. Results indicated that pTx could already significantly improve image quality at 7 T by adopting a suitable RF-Shim. Exploiting the full potential of the pTx-setup, the proposed k(T)-point method provided excellent inversion fidelity, comparable to what is commonly only achievable at 3 T with energy intensive adiabatic pulses. Furthermore, the cumulative energy deposition was simultaneously reduced by over 40% compared to the conventional adiabatic inversions. Regarding the low-FA k(T)-point based excitations, the FA uniformity achieved at 7 T surpassed what is typically obtained at 3 T. Subsequently, automated white and gray matter segmentation not only confirmed the expected improvements in image quality, but also suggests that care should be taken to properly account for the strong local susceptibility effects near cranial cavities. Overall, these findings indicate that the k(T)-point-based pTx solution is an excellent candidate for UHF 3D imaging, where patient safety is a major concern due to the increase of specific absorption rates.

kT -points: short three-dimensional tailored RF pulses for flip-angle homogenization over an extended volume

With Transmit SENSE, we demonstrate the feasibility of uniformly exciting a volume such as the human brain at 7T through the use of an original minimalist transmit k-space coverage, referred to as "k(T) -points." Radio-frequency energy is deposited only at a limited number of k-space locations in the vicinity of the center to counteract transmit sensitivity inhomogeneities. The resulting nonselective pulses are short and need little energy compared to adiabatic or other B 1+-robust pulses available in the literature, making them good candidates for short-repetition time 3D sequences at high field. Experimental verification was performed on three human volunteers at 7T by means of an 8-channel transmit array system. On average, whereas the standard circularly polarized excitation resulted in a 33%-flip angle spread (standard deviation over mean) throughout the brain, and a static radio-frequency shim showed flip angle variations of 17% and up, application of k(T) -point-based excitations demonstrated excellent flip angle uniformity (8%) for a small target flip angle and with sub-millisecond durations.

Generation of GW radiation pulses from a VUV free-electron laser operating in the femtosecond regime

Experimental results are presented from vacuum-ultraviolet free-electron laser (FEL) operating in the self-amplified spontaneous emission (SASE) mode. The generation of ultrashort radiation pulses became possible due to specific tailoring of the bunch charge distribution. A complete characterization of the linear and nonlinear modes of the SASE FEL operation was performed. At saturation the FEL produces ultrashort pulses (30-100 fs FWHM) with a peak radiation power in the GW level and with full transverse coherence. The wavelength was tuned in the range of 95-105 nm.

The CCAAT displacement protein/cut homeodomain protein represses osteocalcin gene transcription and forms complexes with the retinoblastoma protein-related protein p107 and cyclin A

Developmental control of bone tissue-specific genes requires positive and negative regulatory factors to accommodate physiological requirements for the expression or suppression of the encoded proteins. Osteocalcin (OC) gene transcription is restricted to the late stages of osteoblast differentiation. OC gene expression is suppressed in nonosseous cells and osteoprogenitor cells and during the early proliferative stages of bone cell differentiation. The rat OC promoter contains a homeodomain recognition motif within a highly conserved multipartite promoter element (OC box I) that contributes to tissue-specific transcription. In this study, we demonstrate that the CCAAT displacement protein (CDP), a transcription factor related to the cut homeodomain protein in Drosophila melanogaster, may regulate bone-specific gene transcription in immature proliferating osteoblasts. Using gel shift competition assays and DNase I footprinting, we show that CDP/cut recognizes two promoter elements (TATA and OC box I) of the bone-related rat OC gene. Overexpression of CDP/cut in ROS 17/2.8 osteosarcoma cells results in repression of OC promoter activity; this repression is abrogated by mutating OC box I. Gel shift immunoassays show that CDP/cut forms a proliferation-specific protein/DNA complex in conjunction with cyclin A and p107, a member of the retinoblastoma protein family of tumor suppressors. Our findings suggest that CDP/cut may represent an important component of a cell signaling mechanism that provides cross-talk between developmental and cell cycle-related transcriptional regulators to suppress bone tissue-specific genes during proliferative stages of osteoblast differentiation.

The LMP2 polymorphism is associated with susceptibility to acute anterior uveitis in HLA-B27 positive juvenile and adult Mexican subjects with ankylosing spondylitis

INTRODUCTION

An association between polymorphism of the HLA linked LMP2 locus and the development of acute anterior uveitis (AAU) has previously been described in B27 positive white subjects with ankylosing spondylitis (AS). This study evaluated LMP2 alleles in two HLA-B27 positive Mexican populations of patients with spondyloarthropathy known to have a different clinical spectrum of disease from white people.

PATIENTS AND METHODS

The study populations consisted of 90 AS patients from Guadalajara with predominantly adult onset disease and 80 AS patients from Mexico City with predominantly juvenile onset disease. LMP2-CfoI amplified fragment length polymorphisms were determined after polymerase chain reaction amplification and digestion with CfoI restriction enzyme.

RESULTS

There was an increased LMP2A allelic frequency in patients who had had AAU in both Guadalajara (31.8%) and Mexico City (33.3%) when compared with non-AAU patients (15.2% and 17.7% of Guadalajara and Mexico City populations, respectively). The odds ratio relating LMP2A allelic frequency and AAU for the combined population, stratified by age at onset of disease, was 2.51 (p = 0.01). LMP2 alleles did not influence the age at onset of disease or the development of peripheral arthritis.

CONCLUSIONS

These data support the view that polymorphism at the LMP2 locus is associated with the development of AAU in B27 positive subjects with AS. The requirement for both the less common LMP2 allele and HLA-B27 is consistent with the low prevalence of AAU in Mexican patients with spondyloarthritis.

High dose intravenous immunoglobulin (IVIg) in severe refractory rheumatoid arthritis: no evidence for efficacy

OBJECTIVE

A number of reports have recently suggested that high doses of intravenous immunoglobulins may exert beneficial effects in rheumatoid arthritis. One proposed mechanism for this effect is suppression of the generation of pro-inflammatory cytokines, particularly tumor necrosis factor alpha (TNF alpha). We have undertaken a prospective open study of IVIg in patients with severe refractory RA who have failed at least four second line drugs, including methotrexate, and who were receiving NSAIDs and prednisone only.

METHODS

Four patients, 3 males and 1 female, with an average age of 58.25 years (range 41-69 years) and a mean disease duration of 13 years (range 9-14 years), were given IVIg at a dose of 1 g per day for 2 days once a month for 3 months. All patients had active disease at baseline as indicated by an average tender joint count of 15 and an average swollen joint count of 15.25. Clinical assessments were performed according to the WHO/ILAR recommendations at baseline and at monthly intervals up to 4 months after the initiation of IVIg therapy. Patients were classified as responders or non-responders according to the Paulus criteria. Laboratory assessment included a CBC, ESR, and whole blood cytokine ELISA for TNF alpha, TNF R1, and TNF R2 at baseline, 1 day, 7 days and 3 months after the initiation of therapy.

RESULTS

None of the patients met the Paulus criteria for either improvement or worsening. Furthermore, increased TNF alpha production in lipopolysaccharide (LPS) stimulated whole blood assays was consistently noted in 3 out of the 4 patients during the course of therapy which, together with the lack of clinical efficacy, prompted us to curtail further evaluation of this therapy.

CONCLUSION

We were unable to discern any beneficial effects of IVIg therapy, and suggestions that it may enhance TNF alpha generation as well as its substantial cost mandate caution in the future use of this agent in RA.