A therapeutic neutralizing antibody targeting receptor binding domain of SARS-CoV-2 spike protein.

Vaccines and therapeutics are urgently needed for the pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here, we screen human monoclonal antibodies (mAb) targeting the receptor binding domain (RBD) of the viral spike protein via antibody library constructed from peripheral blood mononuclear cells of a convalescent patient. The CT-P59 mAb potently neutralizes SARS-CoV-2 isolates including the D614G variant without antibody-dependent enhancement effect. Complex crystal structure of CT-P59 Fab/RBD shows that CT-P59 blocks interaction regions of RBD for angiotensin converting enzyme 2 (ACE2) receptor with an orientation that is notably different from previously reported RBD-targeting mAbs. Furthermore, therapeutic effects of CT-P59 are evaluated in three animal models (ferret, hamster, and rhesus monkey), demonstrating a substantial reduction in viral titer along with alleviation of clinical symptoms. Therefore, CT-P59 may be a promising therapeutic candidate for COVID-19.

Evaluation of analytical similarity between trastuzumab biosimilar CT-P6 and reference product using statistical analyses.

The evaluation of analytical similarity has been a challenging issue for the biosimilar industry because the number of lots for reference and biosimilar products available at the time of development are limited, whilst measurable quality attributes of target molecule are numerous, which can lead to potential bias or false negative/positive conclusions regarding biosimilarity. Therefore, appropriate statistical analyses are highly desirable to achieve a high level of confidence in the similarity evaluation. A recent guideline for the risk-based statistical approaches recommended by the US Food and Drug Administration provides useful tools to systematically evaluate analytical similarity of biosimilar products compared with reference products. Here, we evaluated analytical similarity of CT-P6, a biosimilar product of trastuzumab, with the reference products (EU-Herceptin® or US-Herceptin®) following these statistical approaches. Various quality attributes of trastuzumab were first ranked based on the clinical impact of each attribute and subsequently adjusted to one of three tiers (Tier 1, Tier 2 and Tier 3) considering the characteristics of the assay, the level of attribute present and the feasibility of statistical analysis. Two biological activities with highest potential clinical impact were evaluated by an equivalent test (Tier 1), and other bioactivities and structural/physicochemical properties relevant to the clinical impact were evaluated by a quality range approach (Tier 2). The attributes with low risk ranking or qualitative assay were evaluated by visual comparison (Tier 3). Analytical similarity assessment analyzed by the three tiers clearly demonstrated that CT-P6 exhibits highly similar structural and physicochemical properties, as well as functional activities, compared with the reference products. There were small differences observed in a few quality attributes between CT-P6 and the reference products, but the differences were very minor, and unlikely to impact on clinical outcome. The recently reported equivalent clinical efficacy of CT-P6 with the reference product further supports that CT-P6 is highly similar compared with the reference product in the view of totality-of-evidence.

Analytical similarity assessment of rituximab biosimilar CT-P10 to reference medicinal product.

CT-P10 (Truxima™) was recently approved as the world's first rituximab biosimilar product in the European Union (EU) and South Korea. To demonstrate biosimilarity of CT-P10 with the reference medicinal product (RMP), extensive 3-way similarity assessment has been conducted between CT-P10, EU-Rituximab and US-Rituximab, focusing on the physicochemical and biological quality attributes. A multitude of state-of-the-art analyses revealed that CT-P10 has identical primary and higher order structures compared to the original product. Purity/impurity profiles of CT-P10 measured by the levels of aggregates, fragments, non-glycosylated form and process-related impurities were also found to be comparable with those of RMPs. In terms of the post-translational modification, CT-P10 contains slightly less N-terminal pyro-glutamate variant, which has been known not to affect product efficacy or safety. Oligosaccharide profiling has revealed that, although CT-P10 contains the same conserved glycan species and relative proportion with the RMPs, the content of total afucosylated glycan in CT-P10 was slightly higher than in EU- or US-Rituximab. Nevertheless, the effect of the observed level of afucosylation in CT-P10 drug product on Fc receptor binding affinity or antibody-dependent cell-mediated cytotoxicity was found to be negligible based on the spiking study with highly afucosylated sample. Arrays of biological assays representative of known and putative mechanisms of action for rituximab have shown that biological activities of CT-P10 are within the quality range of RMPs. Recent results of clinical studies have further confirmed that the CT-P10 exhibits equivalent clinical efficacy and safety profiles compared to EU- and US-Rituximab. The current 3-way similarity assessment together with clinical study results confidently demonstrate that CT-P10 is highly similar with EU- and US-Rituximab in terms of physicochemical properties, biological activities, efficacy, and safety for its final approval as a biosimilar product.

A potent broad-spectrum protective human monoclonal antibody crosslinking two haemagglutinin monomers of influenza A virus.

Effective annual influenza vaccination requires frequent changes in vaccine composition due to both antigenic shift for different subtype hemagglutinins (HAs) and antigenic drift in a particular HA. Here we present a broadly neutralizing human monoclonal antibody with an unusual binding modality. The antibody, designated CT149, was isolated from convalescent patients infected with pandemic H1N1 in 2009. CT149 is found to neutralize all tested group 2 and some group 1 influenza A viruses by inhibiting low pH-induced, HA-mediated membrane fusion. It promotes killing of infected cells by Fc-mediated antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity. X-ray crystallographic data reveal that CT149 binds primarily to the fusion domain in HA2, and the light chain is also largely involved in binding. The epitope recognized by this antibody comprises amino-acid residues from two adjacent protomers of HA. This binding characteristic of CT149 will provide more information to support the design of more potent influenza vaccines.

Physicochemical characterization of Remsima.

Remsima (infliximab) was recently approved as the world's first biosimilar monoclonal antibody (mAb) in both the European Union and Korea. To achieve this, extensive physicochemical characterization of Remsima in relation to Remicade was conducted in order to demonstrate the highly similar properties between the two molecules. A multitude of state-of-the-art analyses revealed that Remsima has identical primary as well as indistinguishable higher order structures compared with the original product. Monomer and aggregate contents of Remsima were also found to be comparable with those of Remicade. In terms of charge isoforms, although Remsima was observed to contain slightly less basic variants than the original antibody, the difference was shown to be largely due to the presence of C-terminal lysine. On the other hand, this lysine was found to be rapidly clipped inside serum in vitro and in vivo, suggesting it has no effect on the biological potency or safety of the drug. Analysis of the glycan contents of the antibodies showed comparable glycan types and distributions. Recent results of clinical studies have further confirmed that the two antibody products are highly similar to each other. Based on this research as well as previous clinical and non-clinical comparability studies, Remsima can be considered as a highly similar molecule to Remicade in terms of physicochemical properties, efficacy, and safety for its final approval as a biosimilar product to Remicade.

Jaw in a day: total maxillofacial reconstruction using digital technology.

BACKGROUND: Tumors of the mandible are complex, often requiring replacement of bone, soft tissue, and teeth. The fibula flap has become a routine procedure in large tumors of the jaw, providing bone and soft tissue at the time of the resection. In current practice, dental reconstruction is delayed for 3 to 6 months, leaving the patient without teeth in the interim. This can be disfiguring and anxiety provoking for the patient. METHODS: In this article, the authors present three patients with benign tumors of the mandible who underwent virtually guided resection, fibula reconstruction, and insertion of an implant-retained dental prosthesis in one operation. In addition, the authors report their early experience using this technique in the maxilla. RESULTS: The authors present a case series of three patients with benign mandibular tumors and one patient with a benign maxillary tumor who underwent total reconstruction using computer-aided design and computer-aided manufacturing technology in a single stage. CONCLUSIONS: In the right situation, total mandibular reconstruction is possible in a single stage. This is demonstrated by the successful outcomes of these patients. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, V.

Familial amyloid polyneuropathy in Korea: the first case report with a proven ATTR Lys35Asn gene.

A 39-year-old man with progressive peripheral neuropathy and autonomic failure showed amyloid deposition on sural nerve biopsy. Direct DNA sequencing of the TTR gene revealed a G to T mutation, causing a Lys to Asn substitution at position 35. This is the first FAP case in Korea which was diagnosed by a DNA test.

Acute exacerbation of hepatitis in liver cirrhosis with very high levels of alpha-fetoprotein but no occurrence of hepatocellular carcinoma.

Aminotransferase levels do not always increase during acute hepatitis or during an acute flare-up of chronic hepatitis. Persistently increased levels of serum alpha-Fetoprotein in an adult with liver disease suggest not only the presence or progression of hepatocellular Carcinoma or its recurrence after hepatic resection or after other therapeutic approaches such as chemotherapy or chemoembolization, but also it suggests that there is an acute exacerbation of hepatitis or liver cirrhosis. We report here on two unusual cases of HBV- & HCV-related liver cirrhosis with acute exacerbation of hepatitis in which there was an insignificant elevation of the aminotransferase levels, but there were markedly increased alpha-Fetoprotein levels observed. The levels of alpha-Fetoprotein decreased gradually in both cases since the beginning of antiviral therapy, which implies that the increased levels were due to aggravation of the accompanying hepatitis. These cases also emphasize that using only the measurement of alpha-Fetoprotein is not sufficient for the diagnosis of hepatocellular carcinoma, and that this diagnosis also requires a more specific measurement such as AFP L3 along with the standard imaging studies.

Efficacy of triple therapy with rabeprazole for Helicobacter pylori infection in relation to CYP2C19 genotype.

BACKGROUND/AIMS: Genetic polymorphism of cytochrome P450 CYP2C19 influences the efficacy of proton pump inhibitor (PPI) in Helicobacter pylori (H. pylori) eradication therapy. We investigated the difference in the cure rates of H. pylori infection by triple (rabeprazole plus amoxacillin and clarithromycin) therapy in relation to CYP2C19 genotype status. METHODS: One hundred and sixteen H. pylori infected patients with gastric ulcer and duodenal ulcer completed the triple therapy with 10 mg of rabeprazole b.i.d., 1,000 mg amoxacillin b.i.d. and 500 mg of clarithromycin b.i.d. for one week. The genotype of CYP2C19 was determined by a PCR-restriction fragment length polymorphism method. RESULTS: According to the univariate analysis, heterozygous extensive metabolizers (hetero EMs) and poor metabolizers (PMs) showed the highest (87.0%) and the lowest (80.0%) eradication rates, respectively. The difference in the therapeutic efficacy of rabeprazole among the different CYP2C19 genotypes was insignificant. With regard to gender, age and smoking history in relation to eradication rate, a statistical significance was noted only with age with odds ratio of 1.063 and p-value of 0.0202. CONCLUSIONS: In the eradication therapy of H. pylori, no statistically significant difference in therapeutic efficacy of rabeprazole was found among different CYP2C19 genotypes.

Acute acalculous cholecystitis associated with cholecystoduodenal fistula and duodenal bleeding. A case report.

Although acute acalculous cholecystitis (AAC) accounts for less than 10% of acute cholecystitis in the adult population, gangrene and perforation are much more frequent compared to the usual cases of acute cholecystitis (calculus cholecystitis). However, spontaneous biliary-enteric fistula is well recognized in AAC, 90% of which are cholecystoduodenal fistula (CDF) though it is an uncommon disorder. The majority of the CDF are caused by cholelithiasis. As patients are usually associated with complicated clinical illness, the diagnosis is often difficult to make and required surgery is often delayed. We have studied a rare complication of acute acalculous cholecystitis which was presented as intermittent upper gastrointestinal bleeding. Ulceration of the superficial branch of the cystic artery has been observed due to acalculous cholecystitis associated with a cholecystoduodenal fistula. We have performed a transfixing ligation of the bleeding vessel, cholecystectomy and simple closure of the CDF. We have finally made a diagnosis of early gallbladder cancer through a frozen section. There was no serious complication after the operation and the patient has achieved an uneventful recovery.