Optimized infection control practices augment the robust protective effect of vaccination for ESRD patients during a hemodialysis facility SARS-CoV-2 outbreak.

BACKGROUND: While dialysis patients are at greater risk of serious SARS-CoV-2 complications, stringent infection prevention measures can help mitigate infection and transmission risks within dialysis facilities. We describe an outbreak of 14 cases diagnosed in a hospital-based outpatient ESRD facility over 13 days in the second quarter of 2021, and our coordinated use of epidemiology, viral genome sequencing, and infection control practices to quickly end the transmission cycle. METHODS: Symptomatic patients and staff members were diagnosed by RT-PCR. Facility-wide screening utilized SARS-CoV-2 antigen tests. SARS-CoV-2 genome sequences were obtained from residual diagnostic specimens. RESULTS: Of the 106 patients receiving dialysis in the facility, 10 were diagnosed with SARS-CoV-2 infection, as was 1 patient support person. Of 3 positive staff members, 2 were unvaccinated and had provided care for 6 and 4 of the affected patients, respectively. Sequencing demonstrated that all cases in the cluster shared an identical B.1.1.7./Alpha substrain. Attack rates were greatest among unvaccinated patients and staff. Vaccine effectiveness was 88% among patients. CONCLUSIONS: Prompt recognition of an infection cluster and rapid intervention efforts successfully ended the outbreak. Alongside consistent adherence to core infection prevention measures, vaccination was highly effective in reducing disease incidence and morbidity in this vulnerable population.

Emergence and onward transmission of a SARS-CoV-2 E484K variant among household contacts of a bamlanivimab-treated patient.

The implementation of monoclonal antibody therapeutics during the COVID-19 pandemic altered the selective pressures encountered by SARS-CoV-2, raising the possibility of selection for resistant variants. Within-host viral evolution was reported in treated immunocompromised individuals but whether this signifies a real risk of onward transmission is unclear. We used a regional SARS-CoV-2 sequencing program to monitor lineages with clinically relevant variants in identified patients, which facilitated analysis of parameters potentially relevant to new variant emergence. Here we describe a newly acquired spike E484K mutation detected within the B.1.311 lineage. Multiple individuals in 2 households of the same extended family were infected. The timing and patterns of spread were consistent with de novo emergence of this E484K variant in the bamlanivimab-treated index patient. Our study suggests that the selective pressures introduced by the widespread administration of these antibodies may warrant increased genomic surveillance to identify and mitigate spread of therapy-induced variants.

Outbreak or pseudo-outbreak? Integrating SARS-CoV-2 sequencing to validate infection control practices in a dialysis facility.

BACKGROUND: The COVID-19 pandemic poses a particularly high risk for End Stage Renal Disease (ESRD) patients so rapid identification of case clusters in ESRD facilities is essential. Nevertheless, with high community prevalence, a series of ESRD patients may test positive contemporaneously for reasons unrelated to their shared ESRD facility. Here we describe a series of 5 cases detected within 11 days in November 2020 in a hospital-based 32-station ESRD facility in Southwest Wisconsin, the subsequent facility-wide testing, and the use of genetic sequence analysis to evaluate links between cases. METHODS: Four patient cases and one staff case were identified in symptomatic individuals by RT-PCR. Facility-wide screening was conducted using rapid SARS-CoV-2 antigen tests. SARS-CoV-2 genome sequences were obtained from residual diagnostic specimens. RESULTS: Facility-wide screening of 47 staff and 107 patients identified no additional cases. Residual specimens from 4 of 5 cases were available for genetic sequencing. Clear genetic differences proved that these contemporaneous cases were not linked. CONCLUSIONS: With high community prevalence, epidemiological data alone is insufficient to deem a case cluster an outbreak. Cluster evaluation with genomic data, when available with a short turn-around time, can play an important role in infection prevention and control response programs.

Acquisition of Cabozantinib-Sensitive MET D1228N Mutation During Progression on Crizotinib in MET-Amplified Triple-Negative Breast Cancer.

BACKGROUND: Targeting of somatic MET mutations using crizotinib has led to strong clinical responses, most frequently in patients with lung cancer, raising the possibility of adopting similar treatment strategies in patients with MET alterations in other cancer types. PATIENT AND METHODS: We describe a patient with advanced triple-negative breast cancer with a 30-fold amplification of MET. Next-generation sequencing of pre- and postprogression biopsies was performed to identify the resistance mechanism emerging after an initial exceptional response to crizotinib. The response of the resistance mutant to type I and II MET inhibitors was assessed in cultured cells. RESULTS: After progressing on crizotinib, a MET-D1228N mutation was detected, which is located in the crizotinib-binding region of the MET kinase domain. Experimental studies demonstrated that this mutation confers complete resistance to crizotinib yet retains cabozantinib sensitivity. Treatment of the patient with cabozantinib led to a subjective improvement in clinical symptoms, but the patient progressed after 7 weeks. CONCLUSION: Although MET mutations are rare in breast cancer, these patients may experience substantial clinical benefit from crizotinib treatment. Nevertheless, drug resistance owing to on-target MET mutations will likely be frequently encountered and comprehensive mechanistic studies to assess sensitivity of these mutants to a series of potential second-line therapies may help guide subsequent treatment for these patients.

Sequential treatment failures in response to BRAF/MEK and immune checkpoint inhibitors mediated by MAP2K2 and B2M mutations in melanoma.

Although the treatment of metastatic melanoma has been significantly improved by both anti-BRAF/MEK and checkpoint immunotherapies, resistance to these treatment modalities remains a substantial clinical problem. Multiple clinical studies are addressing the optimal sequencing of these agents in larger patient cohorts, but successful long-term individualized treatment will likely require the elucidation of resistance mechanisms from post-progression samples. Here, we describe a patient with BRAF-V600E-positive metastatic melanoma who was sequentially treated with BRAF/MEK inhibitors (dabrafenib/trametinib) and checkpoint inhibitor immunotherapy (nivolumab, followed by pembrolizumab). After the emergence of resistance, whole exome sequencing was performed, implicating MAP2K2 and B2M mutations in loss of response to anti-BRAF/MEK and anti-PD1 therapies, respectively.

Genomic case report of a low grade bladder tumor metastasis to lung.

BACKGROUND: We present a rare case where distant metastasis of a low grade bladder tumor was observed. We carried out detailed genomic analysis and cell based experiments on patient tumor samples to study tumor evolution, possible cause of disease and provide personalized treatment strategies. CASE PRESENTATION: A man with a smoking history was diagnosed with a low-grade urothelial carcinoma of the bladder and a concurrent high-grade upper urinary tract tumor. Seven years later he had a lung metastasis. We carried out exome sequencing on all the patient's tumors and peripheral blood (germline) to identify somatic variants. We constructed a phylogenetic tree to capture how the tumors are related and to identify somatic changes important for metastasis. Although distant metastasis of low-grade bladder tumor is rare, the somatic variants in the tumors and the phylogenetic tree showed that the metastasized tumor had a mutational profile most similar to the low grade urothelial carcinoma. The primary and the metastatic tumors shared several important mutations, including in the KMT2D and the RXRA genes. The metastatic tumor also had an activating MTOR mutation, which may be important for tumor metastasis. We developed a mutational signature to understand the biologic processes responsible for tumor development. The mutational signature suggests that the tumor mutations are associated with tobacco carcinogen exposure, which is concordant with the patient's smoking history. We cultured cells from the lung metastasis to examine proliferation and signaling mechanisms in response to treatment. The mTOR inhibitor Everolimus inhibited downstream mTOR signaling and induced cytotoxicity in the metastatic tumor cells. CONCLUSION: We used genomic analysis to examine a rare case of low grade bladder tumor metastasis to distant organ (lung). Our analysis also revealed exposure to carcinogens found is tobacco as a possible cause in tumor development. We further validated that the patient might benefit from mTOR inhibition as a potential salvage therapy in an adjuvant or recurrent disease setting.

Glycogen debranching enzyme (AGL) is a novel regulator of non-small cell lung cancer growth.

Glycogen debranching enzyme (AGL) and Glycogen phosphorylase (PYG) are responsible for glycogen breakdown. We have earlier shown that AGL is a regulator of bladder tumor growth. Here we investigate the role of AGL in non-small cell lung cancers (NSCLC). Short hairpin RNA (shRNA) driven knockdown of AGL resulted in increased anchorage independent and xenograft growth of NSCLC cells. We further establish that an increase in hyaluronic acid (HA) synthesis driven by Hyaluronic Acid Synthase 2 (HAS2) is critical for anchorage independent growth of NSCLC cells with AGL loss. Using gene knockdown approach against HAS2 and by using 4-methylumbelliferone (4MU), an inhibitor of HA synthesis, we show that HA synthesis is critical for growth of NSCLC cells that have lost AGL. We further show NSCLC cells without AGL expression are dependent on RHAMM for HA signaling and growth. Analysis of NSCLC patient datasets established that patients with low AGL/high HAS2 or low AGL/high RHAMM mRNA expression have poor overall survival compared to patients with high AGL/low HAS2 or high AGL/low RHAMM expression. We show for the first time that loss of AGL promotes anchorage independent growth of NSCLC cells. We further show that HAS2 driven HA synthesis and signaling via RHAMM is critical in regulating growth of these cancer cells with AGL loss. Further patients presenting with low AGL and HAS2 or RHAMM over expressing tumors might present the ideal cohort who would respond to inhibitors of HA synthesis and signaling.

Exploiting the enzymatic recognition of an unnatural base pair to develop a universal genetic analysis system.

BACKGROUND: With the invention of the DNA chip, genome-wide analysis is now a reality. Unfortunately, solid-phase detection systems such as the DNA chip suffer from a narrow range in quantification and sensitivity. Today the best methodology for sensitive, wide dynamic range quantification and genotyping of nucleic acids is real-time PCR. However, multiplexed real-time PCR technologies require complicated and costly design and manufacturing of separate detection probes for each new target. METHODS: We developed a novel real-time PCR technology that uses universal energy transfer probes constructed from An Expanded Genetic Information System (AEGIS) for both quantification and genotyping analyses. RESULTS: RNA quantification by reverse transcription-PCR was linear over four orders of magnitude for the simultaneous analysis of beta-actin messenger RNA and 18S ribosomal RNA. A single trial validation study of 176 previously genotyped clinical specimens was performed by endpoint analysis for factor V Leiden and prothrombin 20210A mutation detection. There was concordance for 173 samples between the genotyping results from Invader tests and the AEGIS universal energy transfer probe system for both factor V Leiden and prothrombin G20210A. Two prothrombin and one factor V sample gave indeterminate results (no calls). CONCLUSION: The AEGIS universal probe system allows for rapid development of PCR assays for nucleic acid quantification and genotyping.