Our preliminary data demonstrate that DAAs can be used safely and effectively in patients after kidney transplantation. Patients with proteinuria or lower GFR should be monitored more closely.

BRAF V600E colorectal cancers (CRC) are insensitive to RAF inhibitor monotherapy due to feedback reactivation of receptor tyrosine kinase signaling. Combined RAF and EGFR inhibition exerts a therapeutic effect, but resistance invariably develops through undefined mechanisms. In this study, we determined that CRC progression specimens invariably harbored lesions in elements of the RAS-RAF-MEK-ERK pathway. Genetic amplification of wild-type RAS was a recurrent mechanism of resistance in CRC patients that was not seen in similarly resistant melanomas. We show that wild-type RAS amplification increases receptor tyrosine kinase-dependent activation of RAS more potently in CRC than in melanoma and causes resistance only in the former. Currently approved RAF inhibitors inhibit RAF monomers but not dimers. All the drug-resistant lesions we identified activate BRAF V600E dimerization directly or by elevating RAS-GTP. Overall, our results show that mechanisms of resistance converge on formation of RAF dimers and that inhibiting EGFR and RAF dimers can effectively suppress ERK-driven growth of resistant CRC.

Non-Clostridium difficile enteric infections were identified in 17% of symptomatic patients with IBD. Endoscopic and histologic findings may not differentiate flare from infection. Norovirus and E.coli may play an important role in flare of IBD.

Background Gastrointestinal symptoms are common in patients with COVID-19, but prevalence of co-infection with enteric pathogens is unknown. Aims This study assessed the prevalence of enteric infections among hospitalized patients with COVID-19. Methods We evaluated 4973 hospitalized patients ≥ 18 years of age tested for COVID-19 from March 11 through April 28, 2020, at two academic hospitals. The primary exposure was a positive COVID-19 test. The primary outcome was detection of a gastrointestinal pathogen by PCR stool testing. Results Among 4973 hospitalized individuals, 311 were tested for gastrointestinal infections (204 COVID-19 positive, 107 COVID-19 negative). Patients with COVID-19 were less likely to test positive compared to patients without COVID-19 (10% vs 22%, p < 0.01). This trend was driven by lower rates of non-C.difficile infections (11% vs 22% in COVID-19 positive vs. negative, respectively, p = 0.04), but not C. difficile infection (5.1% vs. 8.2%, p = 0.33). On multivariable analysis, infection with COVID-19 remained significantly associated with lower odds of concurrent GI infection (aOR 0.49, 95% CI 0.24-0.97), again driven by reduced non-C.difficile infection. Testing for both C.difficile and non-C.difficile enteric infection decreased dramatically during the pandemic. Conclusions Pathogens aside from C.difficile do not appear to be a significant contributor to diarrhea in COVID-19 positive patients.