Phase II study of ceralasertib (AZD6738) in combination with durvalumab in patients with advanced/metastatic melanoma who have failed prior anti-PD-1 therapy

BACKGROUND

Modulating the DNA damage response and repair (DDR) pathways is a promising strategy for boosting cancer immunotherapy. Ceralasertib (AZD6738) is an oral inhibitor of the serine/threonine protein kinase ataxia telangiectasia and Rad3-related protein, which is crucial for DDR.

PATIENTS AND METHODS

This phase II trial evaluated ceralasertib plus durvalumab for the treatment of patients with metastatic melanoma who had failed anti-programmed cell death protein 1 therapy.

RESULTS

Among the 30 patients, we observed an overall response rate of 31.0% and a disease control rate of 63.3%. Responses were evident across patients with acral, mucosal, and cutaneous melanoma. The median duration of response was 8.8 months (range, 3.8-11.7 months). The median progression-free survival was 7.1 months (95% confidence interval, 3.6-10.6 months), and the median overall survival was 14.2 months (95% confidence interval, 9.3-19.1 months). Common adverse events were largely hematologic and manageable with dose interruptions and reductions. Exploratory biomarker analysis suggested that tumors with an immune-enriched microenvironment or alterations in the DDR pathway were more likely to respond to the study treatment.

CONCLUSION

We conclude that ceralasertib in combination with durvalumab has promising antitumor activity among patients with metastatic melanoma who have failed anti-programmed cell death protein 1 therapy, and constitute a population with unmet needs.

P–153 Comparison outcome of vitrified human embryos stored in vapor phase liquid nitrogen (LN2) and direct LN2

Study question

Is vapor cryopreserved LN2 storage beneficial for clinical outcomes of vitrified human embryos that are frozen compared to vitrified human embryos having direct contact with LN2.

Summary answer

There are no significant differences compared to clinical outcomes of human embryos stored in LN2 vapor and direct store in LN2.

What is known already

There has been concerned about potential cross-contamination and biohazard issues of embryos for long term storage using direct LN2. This study aimed to compare clinical outcomes of human embryos transfer between vapor phase and liquid LN2.

Study design, size, duration

The embryo has undergone vitrification for long term storage with vapor or direct contact in LN2. After the thawing of the embryo, we checked on the survival rates. We transferred only one or two embryos per patient and kept analyzing the implantation and pregnancy rates

Participants/materials, setting, methods

This retrospective study was carried out from January 2018 to December 2019 with 3272cycles 4713embryos; vitrified for long term storage in vapor phase or direct contact with LN2. We compared the clinical outcomes of frozen embryo transfer cycles using vitrified for long term storage in vapor phase and direct contact with LN2. Clinical outcomes monitored were embryo survival, subsequent implantation and pregnancy after single or double embryo transfer

Main results and the role of chance

A total of 4713 fertilized human embryos are vitrified and then stored in LN2 vapor (n = 2520 cycles) or direct contact LN2 (n = 752 cycles). The study showed that the blastocyst stored in vapor able to retain full development. Survival was 97.8% (vapor) and 97.6% (direct contact LN2), and the vapor storage of human embryos had no significant difference in survival rates after a long term storage. For single blastocyst transfer, pregnancy and implantation rates were 51.5%, 52.4% in vapor, 54.6%, 54.9% in direct LN2; respectively (p=NS). In double blastocyst transfer, the pregnancy and implantation rates were 61.8%, 42.0% in vapor and 64.7%, 44.5% in direct LN2; respectively (p=NS). There were also no significant differences between two groups.

Limitations, reasons for caution

The study showed that the blastocyst stored in vapor can retain full development. A vapor storage system thus is safe and effective for long term vapor storage of vitrified human embryos.Within the limits of this study, there was no detection of an adverse effect of vapor storage.

Wider implications of the findings: Vapor storage systems thus represent a useful alternative for safe and effective long-term storage of vitrified human embryos that can avoid cross contamination chances from having direct contact with LN2.

Trial registration number

Not applicable

A12 PRE-TREATMENT HLADQA1-HLADRB1 TESTING FOR THE PREVENTION OF AZATHIOPRINE-INDUCED PANCREATITIS IN INFLAMMATORY BOWEL DISEASE: A PROSPECTIVE COHORT STUDY

Background

Azathioprine (AZA) therapy has a long history of use in IBD. The need to promote its safe use in this population is ensured by governmental health policy requiring IBD patients to fail low cost drugs, such as AZA, prior to approving funding for more potent biologic therapies. AZA-induced pancreatitis is an idiosyncratic and unpredictable response, occurring in up to 7% of AZA-exposed patients that can lead to patient morbidity, hospitalization, delay in effective IBD management, as well as result in substantial additional health-related costs. There are no tools in clinical practice to identify individuals at risk of AZA-induced pancreatitis. Genetic variation in the HLADQA1-HLADRB1*07:01 haplotype is strongly associated with azathioprine (AZA)-induced pancreatitis in inflammatory bowel disease (IBD).

Aims

To evaluate whether HLA DQA1-HLADRB1*07:01A>C pre-treatment genotype testing in an adult IBD population prior to AZA therapy to guide AZA selection would result in a lower incidence of AZA-induced pancreatitis.

Methods

Participants with IBD (n=599) were screened for HLADQA1-HLADRB1*07:01A>C and participants with a variant genotype were excluded from azathioprine treatment (n=271). Wildtype participants (n=328) were started on azathioprine and followed for 3 months. The incidence of pancreatitis was compared to unscreened historical controls (n=373).

Results

The minor allele frequency of HLADQA1-HLADRB1*07:01 was 30.4% and 30.0% in the screened and unscreened populations respectively. Up to 45.2% of participants were excluded from AZA therapy based on genotype in the HLADQA1-HLADRB1*07:01A>C screened cohort. HLADQA1-HLADRB1*07:01A>C screening resulted in an 11-fold reduction in the odds of azathioprine-induced pancreatitis (0.30% versus 3.4%, OR=0.085, 95%CI=0.011–0.651, p=0.002).

Conclusions

HLA DQA1-HLADRB1*07:01A>C screening substantially reduced the risk of pancreatitis during AZA treatment in patients with IBD. However, using this strategy as a tool for guiding the use of AZA therapy in IBD may eliminate a large proportion of patients from being eligible for treatment with AZA. In regions, where there is access to other IBD therapies, and given the short and long term toxicities associated with AZA, HLA DQA1-HLADRB1*07:01A>C screening may be a clinically-relevant strategy for enhancing the safe use of AZA in IBD. Additionally, cost-effectiveness analyses are needed to further solidify the utility of HLA DQA1-HLADRB1*07:01A>C-screening in IBD populations.

Funding Agencies

Academic Medical Organization of Southwestern Ontario Innovation Fund

Right ventricular longitudinal strain measured using feature-tracking cardiac magnetic resonance is an independent predictor of all cause mortality in patients with severe tricuspid regurgitation

Introduction

Tricuspid regurgitation imposes a volume overload on the right ventricle (RV) that can lead to progressive RV dilation and dysfunction. Overt RV dysfunction is associated with poor prognosis and increased operative risk. Abnormalities of myocardial strain may provide the earliest evidence of ventricular dysfunction. CMR feature-tracking techniques now allow assessment of strain from routine cine-images, without specialized pulse sequences. Whether abnormalities of RV strain measured using CMR feature-tracking have prognostic value in patients with tricuspid regurgitation is unknown

Purpose

To evaluate the prognostic value of CMR feature-tracking derived RV free wall longitudinal strain (RVFWLS) in a large multicenter population of patients with severe tricuspid regurgitation.

Methods

Consecutive patients with severe tricuspid regurgitation undergoing CMR at four US medical centers were included in this study. Feature-tracking RVFWLS was calculated from 4 chamber cine-views (Figure-left panel). The primary endpoint was all-cause death. Cox proportional hazards regression modeling was used to examine the independent association between RVFWLS and death. The incremental prognostic value of RVFWLS was assessed in nested models.

Results

Of the 406 patients in this study,115 died during a median follow-up of 8.8 years. By Kaplan-Meier-analysis, patients with RVFWLS ≥median (−16%) had significantly reduced event free survival compared to those with RVFWLS < median (log-rank p<0.001) (Figure-right panel). By Cox multivariable regression modeling, each 1% worsening in RVFWLS was associated with a 13% increased risk-of-death after adjustement for clinical and imaging risk factors (HR=1.13 per %; p<0.001). Addition of RVFWLS in this model resulted in significant-improvement in the global-chi-square (26 to 65; p<0.0001).

Conclusions

CMR feature-tracking derived RVFWLS is an independent predictor of mortality in patients with severe tricuspid regurgitation, incremental to common clinical and imaging risk factors.

Funding Acknowledgement

Type of funding source: None

High-Resolution Three-Dimensional Imaging of Individual Astrocytes Using Confocal Microscopy

Astrocytes play numerous vital roles in the central nervous system. Accordingly, it is of merit to identify structural and functional properties of astrocytes in both health and disease. The majority of studies examining the morphology of astrocytes have employed immunoassays for markers such as glial fibrillary acidic protein, which are insufficient to encapsulate the considerable structural complexity of these cells. Herein, we describe a method utilizing a commercially available and validated, genetically encoded membrane-associated fluorescent marker of astrocytes, AAV5-GfaABC1D-Lck-GFP. This tool and approach allow for visualization of a single isolated astrocyte in its entirety, including fine peripheral processes. Astrocytes are imaged using confocal microscopy and reconstructed in three dimensions to obtain detailed morphometric data. We further provide an immunohistochemistry procedure to assess colocalization of isolated astrocytes with synaptic markers throughout the z-plane. This technique, which can be utilized via a standard laboratory confocal microscope and Imaris software, allows for detailed analysis of the morphology and synaptic colocalization of astrocytes in fixed tissue. © 2020 by John Wiley & Sons, Inc. Basic Protocol 1: Microinjection of AAV5-GfaABC1D-Lck-GFP into the nucleus accumbens of rats Basic Protocol 2: Tissue processing and immunohistochemistry for post-synaptic density-95 Basic Protocol 3: Single-cell image acquisition Basic Protocol 4: Three-dimensional reconstruction of single cells Basic Protocol 5: Three-dimensional colocalization analysis.

A214 GENETIC VARIATION IN THE FARNESOID X RECEPTOR PREDICTS CROHN’S DISEASE SEVERITY IN FEMALE PATIENTS

Background

Crohn’s disease (CD) is an immune-mediated inflammatory bowel disease defined by episodes of intestinal inflammation. There is now an increasing appreciation of the bile acid-sensing nuclear receptor, FXR, as an important regulator of intestinal inflammation, intestinal permeability and response to bacterial overgrowth. Many of these processes are dysregulated in CD. It is unclear how genetic variation in FXR impacts on CD severity. FXR deficiency is rare. Loss of function mutations in FXR as contributors to CD are unlikely; however, partial loss of function of FXR may contribute to CD progression or severity. Our group demonstrated that FXR-1G>T, a SNV adjacent to the ATG start codon, is linked to reduced transactivation of FXR gene targets. We hypothesized that changes in the intestinal barrier as a result of reduced FXR expression among those who harbor the FXR-1T allele are more likely to exhibit a severe CD phenotype compared to G (reference) allele carriers, and thereby experience a more rapid progression to surgery. Alterations in FXR activity may in part be secondary to genetic variation in the FXR gene.

Aims

To evaluate FXR-1G>T as a genomic biomarker of severity in CD and propose a plausible molecular mechanism.

Methods

A retrospective study (n=542) was conducted in a Canadian cohort of CD patients. Blood samples were obtained for genotypic analysis (FXR-1G>T), as well as determination of the FXR downstream product, fibroblast growth factor (FGF) 19. Primary outcomes included risk and time to first CD-related surgery. To better elucidate a potential molecular basis for the observed effect of FXR-1G>T genotype on CD prognosis (more frequent and early surgery) in female CD patients, we explored a connection between the estrogen receptor (ER)-mediated pathway and genetic variation in FXR using a cell-based model. .

Results

The FXR-1GT genotype was associated with the risk of (odds ratio, OR=3.34, 95%CI=1.58–7.05, p=0.002) and early progression to surgery (hazard ratio, HR=3.00, 95%CI=1.86–4.83, p<0.0001) in CD. Female carriers of the FXR-1GT genotype had the greatest risk of surgery (OR=14.87 95%CI=4.22–52.38, p<0.0001) and early progression to surgery (HR=6.28, 95%CI=3.62–10.90, p<0.0001). Furthermore, women carriers of FXR-1GT polymorphism had a nearly three-fold lower FGF19 plasma concentration compared to women with wildtype FXR-1GG genotype (p<0.0001). In HepG2 cells cotransfected with estrogen receptors (ERα and β) and FXR, presence of estradiol further attenuated variant FXR activity.

Conclusions

FXR-1GT is deleterious to women with CD through ER-mediated attenuation of FXR activation. Female CD FXR-1GT carriers should be considered for more aggressive medical management.

Funding Agencies

CAG, CCC, CIHR

A208 HLA-DQA1*05 GENOTYPE PREDICTS ANTI-DRUG ANTIBODY FORMATION AND LOSS OF RESPONSE DURING INFLIXIMAB THERAPY FOR INFLAMMATORY BOWEL DISEASE

Background

The underlying mechanism for immunogenicity in anti-TNFa-exposed patients with inflammatory bowel disease is poorly understood. Anti-drug antibodies are a leading contributor to infliximab loss of response and adverse drug events. Currently, it is not feasible to identify patients at risk of antibody formation prior to initiating infliximab. The genetic variation HLADQA1*05(rs2097432) has been linked to infliximab antibody formation in a cohort of patients with Crohn’s disease.

Aims

Due to the wide variation in the frequency of HLADQA1* 05 across ethnic groups, we aim to independently evaluate the association between HLADQA1*05and infliximab antibody formation, infliximab loss of response, treatment discontinuation and adverse drug events, in a Canadian inflammatory bowel disease cohort.

Methods

In a retrospective cohort study, infliximab-exposed patients with inflammatory bowel disease (n=262) were screened for the genetic variation, HLADQA1*05A>G(rs2097432). The risk of infliximab anti-drug antibody formation, infliximab loss of response, adverse events, and discontinuation were assessed in wild type (GG) and variant-carrying (AG or AA) individuals.

Results

Forty percent of all participants were HLADQA1*05A>Gvariant carriers, with 79% of participants with infliximab antibodies carrying at least one variant allele. The risk of infliximab antibody formation was higher in HLADQA1*05A>Gvariant carriers in an IBD population (adjusted HR=7.29, 95%CI=2.97–17.191, p=1.46x10-5) independent of age, sex, weight, dose and co-immunosuppression with an immunomodulator. Variant carrier status was associated with an increased risk of infliximab loss of response (adjusted HR=2.34, 95%CI=1.41–3.88, p=0.001) and discontinuation (adjusted HR=2.27, 95%CI=1.46–3.43, p=2.53x10-4) though not with infliximab-associated adverse drug events.

Conclusions

HLADQA1*05 is independently associated with a high risk of infliximab antibody formation in addition to infliximab loss of response and treatment discontinuation. As a result, we propose that pre-emptive genetic screening for the HLADQA1* 05A>Gvariant would be useful in order to predict individuals at risk of developing immunogenicity. There may be a role for genotype-guided application of combination therapy in inflammatory bowel disease.

Funding Agencies

NoneWolfe Medical Research Chair in Pharmacogenomics (MOP-89753 to RBK), the Academic Medical Organization of Southwestern Ontario (INN18-005 to RBK and AW; S17-004 to AW), and Lawson Health Research Institute (IRF-05-19 to AW)

Erythroderma with circulating atypical T-cells, likely Sézary syndrome

The erythrodermic patient is often challenging and requires careful evaluation. Work-up should include an extensive and careful medication history, histological and laboratory testing, and if necessary, molecular studies for the evaluation of underlying malignancy. Herein, we present an erythrodermic patient with repeated biopsies demonstrating a spongiotic process who was found to have circulating atypical T-cells concerning for an underlying erythrodermic T-cell leukemia, most closely related to Sézary syndrome.