Diagnostic limitations and challenges in current clinical guidelines and potential application of metagenomic sequencing to manage pulmonary invasive fungal infections in patients with haematological malignancies.

BACKGROUND: Pulmonary invasive fungal infections (pIFI) disproportionately affect patients with haematological malignancies (HM). Establishing a rapid and accurate diagnosis of pIFI is challenging. Multiple guidelines recommend diagnostic testing of invasive fungal infections but lack consensus and may contribute to inconsistent diagnostic approaches. OBJECTIVE: To identify key diagnostic challenges and review metagenomic sequencing data. SOURCES: PubMed, professional consortium, and scientific society websites search to identify relevant, published, evidence-based clinical guidelines within the past 5 years. PubMed searchs for papers describing clinically relevant novel diagnostic technologies. CONTENT: Current guidelines for patients with HM and suspected pIFI recommend chest computed tomography imaging and specimen testing with microscopic examination (including calcofluor white stain, histopathology, cytopathology, etc.), Aspergillus galactomannan, ß-D-glucan, PCR, and culture, each with certain limitations. Emerging real-world data support the adjunctive use of metagenomic sequencing-based tests for the timely diagnosis of pIFI. IMPLICATIONS: High-quality evidence from robust clinical trials is needed to determine whether guidelines should be updated to include novel diagnostic technologies. Trials should ask whether the combination of powerful novel diagnostics, such as pathogen-agnostic metagenomic sequencing technologies in conjunction with conventional testing can optimize the diagnostic yield for all potential pIFI pathogens that impact the health of patients with HM.

Coronavirus Disease 2019-Associated Pulmonary Aspergillosis: A Noninvasive Screening Model for Additional Diagnostics.

Background: Coronavirus disease 2019 (COVID-19)-associated pulmonary aspergillosis (CAPA) is likely underdiagnosed, and current diagnostic tools are either invasive or insensitive. Methods: A retrospective study of mechanically ventilated patients with COVID-19 admitted to 5 Johns Hopkins hospitals between March 2020 and June 2021 was performed. Multivariable logistic regression was used for the CAPA prediction model building. Performance of the model was assessed using the area under the receiver operating characteristic curve (AUC). Results: In the cohort of 832 patients, 98 (11.8%) met criteria for CAPA. Age, time since intubation, dexamethasone for COVID-19 treatment, underlying pulmonary circulatory diseases, human immunodeficiency virus, multiple myeloma, cancer, or hematologic malignancies were statistically significantly associated with CAPA and were included in the CAPA prediction model, which showed an AUC of 0.75 (95% confidence interval, .70-.80). At a screening cutoff of ≥0.085, it had a sensitivity of 82%, a specificity of 51%, a positive predictive value of 18.6%, and a negative predictive value of 95.3%. (The CAPA screening score calculator is available at www.transplantmodels.com). Conclusions: We developed a CAPA risk score as a noninvasive tool to aid in CAPA screening for patients with severe COVID-19. Our score will also identify a group of patients who are unlikely to have CAPA and who therefore need not undergo additional diagnostics and/or empiric antifungal therapy.

Dual Disseminated Aspergillosis and Mucormycosis Diagnosed at Autopsy: A Report of Two Cases of Coinfection and a Review of the Literature.

Coinfection with invasive aspergillosis and mucormycosis in immunocompromised patients has been reported but is rarely confirmed by tissue histology or autopsy. Serum fungal biomarkers and culture are the primary diagnostic tools but are suboptimal for detecting fungal coinfection. Here, we present the cases of two patients who were immunocompromised due to hematologic malignancy where disseminated aspergillosis and mucormycosis coinfection was only diagnosed upon autopsy despite extensive fungal diagnostic workup, and also review recent literature of such instances of coinfection.

Ordered and deterministic cancer genome evolution after p53 loss.

Although p53 inactivation promotes genomic instability1 and presents a route to malignancy for more than half of all human cancers2,3, the patterns through which heterogenous TP53 (encoding human p53) mutant genomes emerge and influence tumorigenesis remain poorly understood. Here, in a mouse model of pancreatic ductal adenocarcinoma that reports sporadic p53 loss of heterozygosity before cancer onset, we find that malignant properties enabled by p53 inactivation are acquired through a predictable pattern of genome evolution. Single-cell sequencing and in situ genotyping of cells from the point of p53 inactivation through progression to frank cancer reveal that this deterministic behaviour involves four sequential phases-Trp53 (encoding mouse p53) loss of heterozygosity, accumulation of deletions, genome doubling, and the emergence of gains and amplifications-each associated with specific histological stages across the premalignant and malignant spectrum. Despite rampant heterogeneity, the deletion events that follow p53 inactivation target functionally relevant pathways that can shape genomic evolution and remain fixed as homogenous events in diverse malignant populations. Thus, loss of p53-the 'guardian of the genome'-is not merely a gateway to genetic chaos but, rather, can enable deterministic patterns of genome evolution that may point to new strategies for the treatment of TP53-mutant tumours.

Comparison of intrafractional motion with two frameless immobilization systems in surface-guided intracranial stereotactic radiosurgery.

PURPOSE/OBJECTIVES: The aim of this study is to compare intrafractional motion using two commercial non-invasive immobilization systems for linac-based intracranial stereotactic radiosurgery (SRS) under guidance with a surface-guided radiotherapy (SGRT) system. MATERIALS/METHODS: Twenty-one patients who received intracranial SRS were retrospectively selected. Ten patients were immobilized with a vacuum fixation biteplate system, while 11 patients were immobilized with an open-face mask system. A setup margin of 1 mm was used in treatment planning. Real-time surface motion data in 37 treatment fractions using the vacuum fixation system and 44 fractions using the open-face mask were recorded by an SGRT system. Variances of intrafractional motion along three translational directions and three rotational directions were compared between the two immobilization techniques with Levene's tests. Intrafractional motion variation over time during treatments was also evaluated. RESULTS: Using the vacuum fixation system, the average and standard deviations of the shifts were 0.01 ± 0.18 mm, -0.06 ± 0.30 mm, and  0.02 ± 0.26 mm in the anterior-posterior (AP), superior-inferior (SI), and left-right (LR) directions, and -0.02 ± 0.19°, -0.01 ± 0.13°, and 0.01 ± 0.13° for rotations in yaw, roll, and pitch, respectively; using the open-face mask system, the average and standard deviations of the shifts were -0.06 ± 0.20 mm, -0.02 ± 0.35 mm, and 0.01 ± 0.40 mm in the AP, SI, and LR directions, and were 0.05 ± 0.23°, 0.02 ± 0.21°, and 0.00 ± 0.16° for rotations in yaw, roll, and pitch, respectively. There was a significant increase in intrafractional motion variance over time during treatments. CONCLUSION: Patients with the vacuum fixation system had significantly smaller intrafractional motion variation compared to those with the open-face mask system. Using intrafractional motion techniques such as surface imaging system is recommended to minimize dose deviation due to intrafractional motion. The increase in intrafractional motion over time indicates clinical benefits with shorter treatment time.

Characterizing the microbiota of instrumentation in ophthalmology clinics during and beyond the COVID-19 pandemic.

PURPOSE: Increased ophthalmology-specific risk of novel coronavirus 2019 (SARS-CoV-2) transmission is well-established, increasing the fear of infection and causing associated decreased rates of procedures known to save vision. However, the potential transmission from exposure to clinic instrumentation is unknown, including which additional pathogens may be spreading in this context. This study seeks to fill this gap by characterizing the microbiota of instrumentation in ophthalmology clinics during the COVID-19 pandemic and identifying potential sources of pathogenic spread encountered by patients and healthcare workers. METHODS: Thirty-three samples were captured using standard cultures and media. Ten positive and negative controls were used to confirm proper technique. Descriptive statistics were calculated for all samples. Samples were collected from the retina (N = 17), glaucoma (N = 6), cornea (N = 6), and resident (N = 4) clinics with rigorous disinfection standards at a tertiary academic medical center. Standard media cultures and/or polymerase chain reaction (PCR) was performed for each sample. RESULTS: From 33 samples, more than half (17/33, 51.5%) yielded bacterial growth. Using two different molecular methods, three samples (3/33, 9%) tested positive for SARS-CoV-2 (cycle thresholds 36.48, 37.14, and 37.83). There was no significant difference in bacterial growth (95% confidence interval [95% CI]: - 0.644-0.358, p = 0.076) among different clinics (retina, glaucoma, cornea, resident). Staphylococcus (S.) epidermidis grew most frequently (12/35, 34%), followed by S. capitis (7/35, 20%), Micrococcus luteus (2/35, 5.7%), Corynebacterium tuberculostearicum (2/35, 5.7%), and Cutibacterium ([C.], Propionibacterium) acnes (2/35, 5.7%). C. acnes growth was more frequent with imaging device forehead rests (2/7, 28.6%) than other surfaces (0/26, 0%, 95% CI: 0.019-0.619, p = 0.040). No samples isolated fungus or adenovirus. CONCLUSIONS: Most samples across subspecialty clinic instrumentation grew bacteria, and several tested positive for SARS-CoV-2. Many isolated pathogens have been implicated in causing infections such as endophthalmitis, conjunctivitis, uveitis, and keratitis. The clinical implications of the ophthalmology microbiome for transmitting nosocomial infections warrant optimization of disinfection practices, strategies for mitigating spread, and additional study beyond the pandemic.

Coronavirus Disease 2019-Associated Pulmonary Aspergillosis in Mechanically Ventilated Patients.

BACKGROUND: Coronavirus disease 2019 (COVID-19)-associated pulmonary aspergillosis (CAPA) occurs in critically ill patients with COVID-19. Risks and outcomes remain poorly understood. METHODS: A retrospective cohort study of mechanically ventilated adult patients with COVID-19 admitted to 5 Johns Hopkins hospitals was conducted between March and August 2020. CAPA was defined using composite clinical criteria. Fine and Gray competing risks regression was used to analyze clinical outcomes and, multilevel mixed-effects ordinal logistic regression was used to compare longitudinal disease severity scores. RESULTS: In the cohort of 396 people, 39 met criteria for CAPA. Patients with CAPA were more likely than those without CAPA to have underlying pulmonary vascular disease (41% vs 21.6%, respectively; P = .01), liver disease (35.9% vs 18.2%; P = .02), coagulopathy (51.3% vs 33.1%; P = .03), solid tumors (25.6% vs 10.9%; P = .02), multiple myeloma (5.1% vs 0.3%; P = .03), and corticosteroid exposure during the index admission (66.7% vs 42.6%; P = .005), and had lower body mass indexes (median, 26.6 vs 29.9 [calculated as weight in kilograms divided by height in meters squared]; P = .04). Patients with CAPA had worse outcomes, as measured by ordinal severity of disease scores, requiring longer time to improvement (adjusted odds ratio, 1.081.091.1; P < .001), and advancing in severity almost twice as quickly (subhazard ratio, 1.31.82.5; P < .001). They were intubated twice as long as those without CAPA (subhazard ratio, 0.40.50.6; P < .001) and had longer hospital stays (median [interquartile range], 41.1 [20.5-72.4) vs 18.5 [10.7-31.8] days; P < .001). CONCLUSION: CAPA is associated with poor outcomes. Attention to preventive measures (screening and/or prophylaxis) is warranted in people with high risk of CAPA.

Recognition of Diagnostic Gaps for Laboratory Diagnosis of Fungal Diseases: Expert Opinion from the Fungal Diagnostics Laboratories Consortium (FDLC).

Fungal infections are a rising threat to our immunocompromised patient population, as well as other nonimmunocompromised patients with various medical conditions. However, little progress has been made in the past decade to improve fungal diagnostics. To jointly address this diagnostic challenge, the Fungal Diagnostics Laboratory Consortium (FDLC) was recently created. The FDLC consists of 26 laboratories from the United States and Canada that routinely provide fungal diagnostic services for patient care. A survey of fungal diagnostic capacity among the 26 members of the FDLC was recently completed, identifying the following diagnostic gaps: lack of molecular detection of mucormycosis; lack of an optimal diagnostic algorithm incorporating fungal biomarkers and molecular tools for early and accurate diagnosis of Pneumocystis pneumonia, aspergillosis, candidemia, and endemic mycoses; lack of a standardized molecular approach to identify fungal pathogens directly in formalin-fixed paraffin-embedded tissues; lack of robust databases to enhance mold identification with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry; suboptimal diagnostic approaches for mold blood cultures, tissue culture processing for Mucorales, and fungal respiratory cultures for cystic fibrosis patients; inadequate capacity for fungal point-of-care testing to detect and identify new, emerging or underrecognized, rare, or uncommon fungal pathogens; and performance of antifungal susceptibility testing. In this commentary, the FDLC delineates the most pressing unmet diagnostic needs and provides expert opinion on how to fulfill them. Most importantly, the FDLC provides a robust laboratory network to tackle these diagnostic gaps and ultimately to improve and enhance the clinical laboratory's capability to rapidly and accurately diagnose fungal infections.

A Case of Scedosporium aurantiacum Infection in the United States.

Scedosporium aurantiacum is one of the emergent opportunistic fungal pathogens among immunocompromised hosts. Colonization of S. aurantiacum can also occur in patients with underlying lung diseases such as cystic fibrosis. S. aurantiacum is highly resistant to multiple antifungal agents, and management of the infected patients can be very challenging compared to those infected with other species of Scedosporium. Clinical cases have been geographically restricted mostly in Australia with a small number of cases identified in Europe and Japan. Although clinical isolates of S. aurantiacum from the USA have been included in several research studies, no clinical case of S. aurantiacum infection from the USA has been described. We report a case of S. aurantiacum infection acquired in the SA. Awareness of S. aurantiacum among healthcare providers and the species-level identification for Scedosporium are critically important for appropriate selection of antifungal agents and improvement of treatment outcomes.

A Comprehensive Evaluation of Risk Factors for Pneumocystis jirovecii Pneumonia in Adult Solid Organ Transplant Recipients: A Systematic Review and Meta-analysis.

BACKGROUND: There is no consensus guidance on when to reinitiate Pneumocystis jirovecii pneumonia (PJP) prophylaxis in solid organ transplant (SOT) recipients at increased risk. The 2019 American Society of Transplantation Infectious Diseases Community of Practice (AST IDCOP) guidelines suggested to continue or reinstitute PJP prophylaxis in those receiving intensified immunosuppression for graft rejection, cytomegalovirus (CMV) infection, higher dose of corticosteroids, or prolonged neutropenia. METHODS: A literature search was conducted evaluating all literature from existence through April 22, 2020, using MEDLINE and EMBASE. (The International Prospective Register of Systematic Reviews registration number: CRD42019134204). RESULTS: A total of 30 studies with 413 276 SOT recipients were included. The following factors were associated with PJP development: acute rejection (pooled odds ratio [pOR], 2.35; 95% confidence interval [CI], 1.69-3.26); study heterogeneity index [I2] = 23.4%), CMV-related illnesses (pOR, 3.14; 95% CI, 2.30-4.29; I2 = 48%), absolute lymphocyte count <500 cells/mm3 (pOR, 6.29; 95% CI, 3.56-11.13; I2 = 0%), BK polyomavirus-related diseases (pOR, 2.59; 95% CI, 1.22-5.49; I2 = 0%), HLA mismatch ≥3 (pOR, 1.83; 95% CI, 1.06-3.17; I2 = 0%), rituximab use (pOR, 3.03; 95% CI, 1.82-5.04; I2 = 0%), and polyclonal antibodies use for rejection (pOR, 3.92; 95% CI, 1.87-8.19; I2 = 0%). On the other hand, sex, CMV mismatch, interleukin-2 inhibitors, corticosteroids for rejection, and plasmapheresis were not associated with developing PJP. CONCLUSIONS: PJP prophylaxis should be considered in SOT recipients with lymphopenia, BK polyomavirus-related infections, and rituximab exposure in addition to the previously mentioned risk factors in the American Society of Transplantation Infectious Diseases Community of Practice guidelines.

Proportion of Patients in Phase I Oncology Trials Receiving Treatments That Are Ultimately Approved.

BACKGROUND: Phase I oncology trials are often regarded as a therapeutic option for patients. However, such claims have relied on surrogate measures of benefit, such as objective response. METHODS: Using a systematic search of publications, we assessed the therapeutic value of phase I cancer trial participation by determining the probability that patients will receive active doses of treatments that eventually receive FDA approval or a National Comprehensive Cancer Network (NCCN) guideline recommendation for their indication. ClinicalTrials.gov, PubMed, American Society of Clinical Oncology reports, NCCN guidelines, and Drugs@FDA were searched between May 1, 2018, and July 31, 2018. All statistical tests were 2-sided. RESULTS: A total of 1000 phase I oncology trials initiated between 2005 and 2010 and enrolling 32 582 patients were randomly sampled from 3229 eligible trials on ClinicalTrials.gov. A total of 386 (1.2%) patients received a treatment that was approved by the US Food and Drug Administration for their malignancy at a dose delivered in the trial; including NCCN guideline recommendations, the number and proportion are 1168 (3.6%). Meta-regression showed a statistically significantly greater proportion of patients receiving a drug that was ultimately FDA approved in biomarker trials (rate ratio = 4.49, 95% confidence interval [CI] = 1.53 to 13.23; P = .006) and single-indication trials (rate ratio = 3.32, 95% CI = 1.21 to 9.15; P = .02); proportions were statistically significantly lower for combination vs monotherapy trials (rate ratio = 0.09, 95% CI = 0.01 to 0.68; P = .02). CONCLUSIONS: One in 83 patients in phase I cancer trials received a treatment that was approved for their indication at the doses received. Given published estimates of serious adverse event rates of 10%-19%, this represents low therapeutic value for phase I trial participation.

Evaluation of a PCR-electrospray ionization mass spectrometry platform for detection and identification of fungal pathogens directly from prospectively collected bronchoalveolar lavage specimens.

The incidence of invasive fungal infections is on the rise worldwide due to the growth of the immunocompromised population. We report here the use of a diagnostic assay that utilizes a universal extraction method, broad spectrum PCR amplification and analysis via electrospray ionization mass spectrometry (PCR/ESI-MS) to detect and identify more than 200 pathogenic fungi directly from bronchoalveolar lavage (BAL) specimens in less than 8 hours. In this study, we describe both analytical and clinical performance of the assay, when run with prospectively collected clinical BAL specimens. In 146 patients with probable and possible fungal infections defined by EORTC/MSG (European Organization for Research and Treatment of Cancer/Mycoses Study Group) criteria, the PCR/ESI-MS assay demonstrated a sensitivity of 90.9% (95% CI: 76.4-96.9%) and a specificity of 82.3% (95% CI: 74.2-88.2%). This data demonstrates the utility of a non-culture based broad fungal targets molecular diagnostic tool for rapid and accurate diagnosis of invasive fungal infections in patients at risk of developing fungal diseases.

A Multicenter, Longitudinal Cohort Study of Cryptococcosis in Human Immunodeficiency Virus-negative People in the United States.

BACKGROUND: Cryptococcosis is increasingly recognized in people without human immunodeficiency virus (HIV). METHODS: A multicenter, prospective cohort study was performed in 25 US centers. Consenting patients were prospectively followed for ≤2 years. Neurological morbidities were assessed with longitudinal event depiction and functional scores (Montreal Cognitive Assessment [MoCA]). Risks of death were analyzed using Cox regression. RESULTS: One hundred forty-five subjects were enrolled. Most were male (95; 65.5%) and had immunosuppression (120; 82.8%), including solid organ transplant (SOT; 33.8%), autoimmunity (15.9%), and hematologic malignancies (11.7%). Disease involved the central nervous system (CNS) in 71 subjects (49%). Fever was uncommon, documented in 40 (27.8%) subjects, and absence was associated with diagnostic delay (mean: 48.2 vs 16.5 days; P = .007). Abnormal MoCA scores (<26) were predictive of CNS disease; low scores (<22) were associated with poor long-term cognition. Longitudinal event depiction demonstrated frequent complications in people with CNS disease; 25 subjects (35.2%) required >1 lumbar puncture and 8 (11.3%) required ventriculostomies. In multivariable models, older age (>60 years) was associated with higher risks of death (hazard ratio [HR], 2.14; 95% confidence interval [CI], 1.05-4.38; P = .036), and lower risks were noted with underlying hematologic malignancy (HR, 0.29; 95% CI, 0.09-0.98; P = .05) and prior SOT (HR, 0.153; 95% CI, 0.05-0.44; P = .001). CONCLUSIONS: Despite aggressive antifungal therapies, outcomes of CNS cryptococcosis in people without HIV are characterized by substantial long-term neurological sequelae. Studies are needed to understand mechanism(s) of cognitive decline and to enable better treatment algorithms.

Disseminated sporotrichosis following iatrogenic immunosuppression for suspected pyoderma gangrenosum.

Sporotrichosis is an infection caused by the dimorphic fungus Sporothrix schenckii and related species that often arises from traumatic inoculation of inhabited soil and organic debris into skin. The infection is usually limited to the skin in immunocompetent patients, usually as lymphocutaneous sporotrichosis. Accurate diagnosis rests on clinical data and culture, and might be facilitated by biopsy identification of suppurative and granulomatous inflammation with fungal elements. In this Grand Round, we present a dramatic case of cutaneous sporotrichosis initially presented with an atypical large ulcer without associated lymphocutaneous spread, clinically mimicking pyoderma gangrenosum, and subsequently progressed to disseminated sporotrichosis in the setting of iatrogenic immunosuppression. We further review the clinical features, risk factors, and treatment of these disseminated sporotrichosis cases, and discuss the need for improved awareness of this fungus' potential link to cause disseminated and invasive fungal infections.

Pleural fluid secondary to pulmonary cryptococcal infection: a case report and review of the literature.

BACKGROUND: Pulmonary Cryptococcosis (PC) is diagnosed with increasing incidence in recent years, but it does not commonly involve the pleural space. Here, we report a HIV-negative case with advanced stage IIIB non-small cell lung cancer (NSCLC) treated with radiation therapy presented with dyspnea, a new PET-positive lung mass and bilateral pleural effusion suspecting progressive cancer. However, the patient has been diagnosed as pulmonary cryptococcal infection and successfully treated with oral fluconazole therapy. CASE PRESENTATION: A 77-year-old male with advanced stage non-small cell lung cancer treated with combined chemo-radiation therapy who presented with progressive dyspnea, a new PET-positive left lower lobe lung mass and bilateral pleural effusions. Initial diagnostic thoracentesis and bronchoscopy yielded no cancer, but instead found yeast forms consistent with cryptococcal organisms in the transbronchial biopsies of the left lower lobe lung mass. Subsequent to this, the previously collected pleural fluid culture showed growth of Cryptococcus neoformans. The same sample of pleural effusion was tested and was found to be positive for crytococcal antigen (CrAg) by a lateral flow assay (LFA). The patient has been treated with oral fluconazole therapy resulting in gradual resolution of the nodular infiltrates. CONCLUSION: PC should be considered in immunosuppressed cancer patients. Additionally, concomitant pleural involvement in pulmonary cryptococcal infections may occur. The incidence of false positive 18FDG-PET scans in granulomatous infections and the use of CrAg testing in pleural fluid to aid in diagnosis are reviewed.

Angioinvasive, cutaneous infection due to Colletotrichum siamense in a stem cell transplant recipient: Report and review of prior cases.

Colletotrichum is an important fungal plant pathogen, yet an uncommon cause of human disease. Herein we report a case of invasive, cutaneous infection in a stem cell transplant recipient due to Colletotrichum species, with accompanying review of the literature. The infection was successfully treated with a combination of liposomal amphotericin B and voriconazole. Multilocus phylogenetic analysis revealed that the distinct isolate belongs to Colletotrichum siamense, a member of the Colletotrichum gloeosporioides species complex not previously described as a human pathogen. Colletotrichum infection remains in the differential for skin lesions in the immune compromised host.

Immuno-PET Imaging to Assess Target Engagement: Experience from 89Zr-Anti-HER3 mAb (GSK2849330) in Patients with Solid Tumors.

PET imaging with radiolabeled drugs provides information on tumor uptake and dose-dependent target interaction to support selection of an optimal dose for future efficacy testing. In this immuno-PET study of the anti-human epidermal growth factor receptor (HER3) mAb GSK2849330, we investigated the biodistribution and tumor uptake of 89Zr-labeled GSK2849330 and evaluated target engagement as a function of antibody mass dose. Methods:89Zr-GSK2849330 distribution was monitored in 6 patients with HER3-positive tumors not amenable to standard treatment. Patients received 2 administrations of 89Zr-GSK2849330. Imaging after tracer only was performed at baseline; dose-dependent inhibition of 89Zr-GSK2849330 uptake in tumor tissues was evaluated 2 wk later using increasing doses of unlabeled GSK2849330 in combination with the tracer. Up to 3 PET scans (2 hours post infusion [p.i.] and days 2 and 5 p.i.) were performed after tracer administration. Biodistribution and tumor targeting were assessed visually and quantitatively using SUV. The 50% and 90% inhibitory mass doses (ID50 and ID90) of target-mediated antibody uptake were calculated using a Patlak transformation. Results: At baseline, imaging with tracer showed good tumor uptake in all evaluable patients. Predosing with unlabeled mAb reduced the tumor uptake rate in a dose-dependent manner. Saturation of 89Zr-mAb uptake by tumors was seen at the highest dose (30 mg/kg). Despite the limited number of patients, an exploratory ID50 of 2 mg/kg and ID90 of 18 mg/kg have been determined. Conclusion: In this immuno-PET study, dose-dependent inhibition of tumor uptake of 89Zr-GSK2849330 by unlabeled mAb confirmed target engagement of mAb to the HER3 receptor. This study further validates the use of immuno-PET to directly visualize tissue drug disposition in patients with a noninvasive approach and to measure target engagement at the site of action, offering the potential for dose selection.

A Multiaddressable Dyad with Switchable Cyan/Magenta/Yellow Colors for Full-Color Rewritable Paper.

Reversible multicolor displays on solid media created from single-molecule pigments are a long-awaited goal. Herein, a new and simple molecular dyad, which can undergo switchable cyan (C), magenta (M), and yellow (Y) color changes in both solution and the solid state upon exposure to light, water/acid, and nucleophiles, has been designed and synthesized. The stimuli used herein can be applied independent of each other, which is beneficial for color changes without mutual interference. For comparison, mixtures of the two molecular switching motifs that form the basis of the dyad were also studied. The dyad greatly outperforms the corresponding mixed system with respect to reversible color switching on the paper substrate. Its potential for full-color rewritable paper with excellent reversibility has been demonstrated. Legible multicolor prints, that is, high color contrast and resolution, good dispersion, and excellent reversibility, were achieved by using common water-jet and light-based printers. This work provides a very promising approach for the further development of full-color switchable molecules, materials, and displays.