Sharma, Vivek R.

Objective: In this study, we evaluate the utility of ctDNA analysis in a large cohort of patients for whom ctDNA testing was ordered commercially with real-world application. Summary Background Data: Circulating tumor DNA (ctDNA) has emerged as a prognostic and predictive biomarker for assessing post-surgical molecular residual disease (MRD) and response to treatment. Methods: A real-world data analysis was performed using commercial ctDNA testing (SignateraTM) from patients (N=795, n=5,971 plasma samples) with stage I-III colon cancer treated at multiple US institutions. The association of ctDNA detection within the MRD window, during surveillance, and the impact of ACT was correlated with patient outcomes. Results: ctDNA-positive patients during the MRD window and surveillance showed significantly shorter DFS compared to ctDNA-negative patients (hazard ratio (HR): 9.85, P<0.0001; HR: 26.91, P<0.0001). Multivariate analysis of the MRD window revealed ctDNA-positivity as the most significant factor associated with inferior DFS (adjHR: 7.7, P<0.001). MRD-positive patients who received ACT showed improved DFS compared to patients observed post-surgery (adjHR: 6.1, FDR adj P=0.0007). No ACT benefit was observed in MRD-negative patients (adj HR: 1.20, FDR adj P=0.768). On evaluating ctDNA dynamics from MRD to surveillance, patients who remained ctDNA-positive or converted from negative to positive showed a significantly inferior DFS (HR: 34.40, P<0.0001; HR: 13.65, P<0.0001) compared to persistently ctDNA-negative patients. Conclusions: Postsurgical ctDNA detection is prognostic of relapse and potentially predictive of ACT benefit in patients with resectable colon cancer, which may enable personalized surveillance, intervention, and/or trial options, ultimately improving patient outcomes.

Congenital factor V deficiency (FVD) is a rare bleeding disorder. In this study, we investigated the genetic basis in an African American patient with factor V activity 3%. Custom sequence capture and targeted next-generation (NGS) sequencing of the F5 gene were undertaken followed by PCR and Sanger sequencing. Two novel variants were identified. In silico analyses correlated clinically with the patient's factor V activity and hemorrhagic tendency. A review of the literature regarding these genomic alterations is presented. We described two novel mutations causing moderate FVD. The first, Chr1:g.169483698C>A with cDNA change (F5):c.6529-1G>T, occurred in a conserved nucleotide at the canonical acceptor splice site of intron 24. The second, Chr1:g.169515775C>T with cDNA change (F5):c.1667G>A, was a missense variant of exon 11, affecting a highly conserved amino acid in the A2 domain. Further research into the mechanisms of F5 mutations leading to FVD and residual factor V expression are needed.

Background: Approximately 5000 snake bites are reported in the United States (US) annually with half of these patients being admitted. Crotalinae species are the most numerous; coral and imported exotic snakes cause a smaller number. Snake venoms are highly stable chemically complex mixtures of proteins. Quantity and composition vary with species and geographic location. Although enzymes contribute to the deleterious effects of the venom, the lethal components may be the smaller low molecular-weight polypeptides. Crotalinae envenomation is known to contain thrombin-like glycoproteins that can induce coagulopathy ranging from asymptomatic lab abnormality to disseminated intravascular coagulopathy (DIC) and life-threatening hemorrhage. In certain geographical areas of the United States thrombocytopenia, hypofibrinogenemia and coagulopathy are common hematological abnormalities, and ones that dictate both a reason for treatment with antivenom as well as an important monitor of therapeutic efficacy. Data on hematological abnormalities following envenomation by crotaline species in Northeast Florida/Southwest Georgia has not been reported before. Methods: We conducted a retrospective review of envenomations that presented to the University of Florida at Jacksonville from April 2013 to October 2018. Patients had to be 16 years or older without any pre-existing hematologic disorder or use of anticoagulant medications. Data including Complete Blood Count, Prothrombin Time (PT), activated Partial Thromboplastin Time (aPTT) and Fibrinogen were measured on presentation, and 4 hours after. Crotaline Fab antivenom (CroFab®) administration was noted if done. Adverse events associated with antivenom therapy, recurrence phenomena, delayed onset of symptoms, and performance of fasciotomy were also recorded. Results: Overall, 119 snakebites were evaluated. The majority were identified as Crotalinae - 25 water moccasin, copperhead or cottonmouth (Agkistrodon piscivorus, Agkistrodon contortrix) bites and 34 rattlesnake (Sistrurus miliarius, Crotalus adamanteus) bites. Male sex dominated the sample with most patients middle-aged (Table 1). More than 80% of patients arrived within 6 hours following the bite. Over 60% of patients received crotaline Fab antivenom. Results are presented in Table 2. Around 12% of patients with water moccasin, copperhead or cottonmouth (Agkistrodon piscivorus, Agkistrodon contortrix) bites had coagulopathy on admission. This compares similarly to data from South Carolina previously showing a 10.89% rate following copperhead bites (Qureshi et al. Blood 2010;116(21):4753). The rate of coagulopathy with rattlesnake bites was however much higher in North Florida at 20.6% - compared to 5.26% in the South Carolina series. Rates of DIC or severe hemorrhage were 8% for water moccasin, copperhead or cottonmouth (Agkistrodon piscivorus, Agkistrodon contortrix) bites and 5.9% for rattlesnake (Sistrurus miliarius, Crotalus adamanteus) bites. When hemostatic defects were looked at separately, the most common abnormality induced was PT/aPTT derangement, followed by hypofibrinogenemia and then thrombocytopenia. This pattern was the same as reported in South Carolina. Recurrence phenomena was observed after 4 hours in a number of patients, however the significance of this remains uncertain as most of these patients remained clinically stable without worsening symptoms. Anaphylactic reaction to the antivenom developed in one patient. Conclusions: In this sample from North Florida, deranged PT/aPTT was the most common hematologic abnormality following envenomation, followed by hypofibrinogenemia and a low rate of thrombocytopenia. Similarities with data from South Carolina were noted, although rattlesnake bites had 4 times higher incidence of coagulopathy in North Florida. DIC or severe hemorrhage was a notable toxicity, affecting 6-8% of Crotalinae cases. Hematologic effects of envenomation do seem to vary by geographic areas in the United States and physicians would benefit from local data to better manage these patients. Disclosures No relevant conflicts of interest to declare.