Conjugation of a peptide to an antibody engineered with free cysteines dramatically improves half-life and activity.

The long circulating half-life and inherently bivalent architecture of IgGs provide an ideal vehicle for presenting otherwise short-lived G-protein-coupled receptor agonists in a format that enables avidity-driven enhancement of potency. Here, we describe the site-specific conjugation of a dual agonist peptide (an oxyntomodulin variant engineered for potency and in vivo stability) to the complementarity-determining regions (CDRs) of an immunologically silent IgG4. A cysteine-containing heavy chain CDR3 variant was identified that provided clean conjugation to a bromoacetylated peptide without interference from any of the endogenous mAb cysteine residues. The resulting mAb-peptide homodimer has high potency at both target receptors (glucagon receptor, GCGR, and glucagon-like peptide 1 receptor, GLP-1R) driven by an increase in receptor avidity provided by the spatially defined presentation of the peptides. Interestingly, the avidity effects are different at the two target receptors. A single dose of the long-acting peptide conjugate robustly inhibited food intake and decreased body weight in insulin resistant diet-induced obese mice, in addition to ameliorating glucose intolerance. Inhibition of food intake and decrease in body weight was also seen in overweight cynomolgus monkeys. The weight loss resulting from dosing with the bivalently conjugated dual agonist was significantly greater than for the monomeric analog, clearly demonstrating translation of the measured in vitro avidity to in vivo pharmacology.

Neurofilament light chain as an indicator of exacerbation prior to clinical symptoms in multiple sclerosis.

BACKGROUND: Biomarkers may be a sensitive measure of disease activity in patients with multiple sclerosis (pwMS). OBJECTIVE: A pwMS had a marked increase of neurofilament light chain (NfL) in CSF 9-weeks prior to a clinical exacerbation. METHODS AND RESULTS: Brain MRI, CSF, EDSS were measured at baseline, 6 weeks and 28 weeks. The patient had an exacerbation at week 15 of study but the NfL measured at week 6 were found to show a nearly 3-fold increase of CSF NfL levels prior to symptoms when the NfL levels were later measured. CONCLUSION: This is an example supporting the usefulness of NfL in monitoring disease activity in pwMS which may predict disease activity prior to a clinical exacerbation.

Reducing return of disease activity in patients with relapsing multiple sclerosis transitioned from natalizumab to teriflunomide: 12-month interim results of teriflunomide therapy.

BACKGROUND: Natalizumab is an effective treatment for relapsing multiple sclerosis. Return of disease activity upon natalizumab discontinuance creates the need for follow-up therapeutic strategies. OBJECTIVE: To assess the efficacy of teriflunomide following natalizumab discontinuance in relapsing multiple sclerosis patients. METHODS: Clinically stable relapsing multiple sclerosis patients completing 12 or more consecutive months of natalizumab, testing positive for anti-John Cunningham virus antibody, started teriflunomide 14 mg/day, 28 ± 7 days after their final natalizumab infusion. Physical examination, Expanded Disability Status Scale, laboratory assessments, and brain magnetic resonance imaging were performed at screening and multiple follow-up visits. RESULTS: Fifty-five patients were enrolled in the study. The proportion of patients relapse-free was 0.94, restricted mean time to first gadolinium-enhancing lesion was 10.9 months and time to 3-month sustained disability worsening was 11.8 months. The mean number of new or enlarging T2 lesions per patient at 12 months was 0.42. Exploratory analyses revealed an annualized relapse rate of 0.08, and a proportion of patients with no evidence of disease activity of 0.68. Forty-seven patients (85.5%) reported adverse events, 95% of which were mild to moderate. CONCLUSIONS: Teriflunomide therapy initiated without natalizumab washout resulted in a low rate of return of disease activity. Clinicians may consider this a worthwhile strategy when transitioning clinically stable patients off natalizumab to another therapy.ClinicalTrials.gov Identifier: NCT01970410.

An efficient process of generating bispecific antibodies via controlled Fab-arm exchange using culture supernatants.

Bispecific antibody generation is actively pursued for therapeutic and research antibody development. Although there are multiple strategies for generating bispecific antibodies (bsAbs); the common challenge is to develop a scalable method to prepare bsAbs with high purity and yield. The controlled Fab-arm exchange (cFAE) method combines two parental monoclonal antibodies (mAbs), each with a matched point mutation, F405L and K409R in the respective CH3 domains. The conventional process employs two steps: the purification of two parental mAbs from culture supernatants followed by cFAE. Following a reduction/oxidation reaction, the bispecific mAb is formed with greater than 95% heterodimerization efficiency. In this study, cFAE was initiated in culture supernatants expressing the two parental mAbs, thereby eliminating the need to first purify the parental mAbs. The bsAbs formed in culture supernatant was then purified using a Protein A affinity chromatography. The BsAbs generated in this manner had efficiency comparable to the conventional method using purified parental mAbs. BsAbs prepared by two different routes showed indistinguishable characteristics by SDS capillary electrophoresis, analytical size exclusion, and cation exchange chromatography. This alternative method significantly shortened timelines and reduced resources required for bsAb generation, providing an improved process with potential benefits in large-scale bsAb preparation, as well as for HTP small-scale bsAb matrix selection.

Characterization of a high-affinity human antibody with a disulfide bridge in the third complementarity-determining region of the heavy chain.

Disulfide bridges are common in the antigen-binding site from sharks (new antigen receptor) and camels (single variable heavy-chain domain, VHH), in which they confer both structural diversity and domain stability. In human antibodies, cysteine residues in the third complementarity-determining region of the heavy chain (CDR-H3) are rare but naturally encoded in the IGHD germline genes. Here, by panning a phage display library designed based on human germline genes and synthetic CDR-H3 regions against a human cytokine, we identified an antibody (M3) containing two cysteine residues in the CDR-H3. It binds the cytokine with high affinity (0.4 nM), recognizes a unique epitope on the antigen, and has a distinct neutralization profile as compared with all other antibodies selected from the library. The two cysteine residues form a disulfide bridge as determined by mass spectrometric peptide mapping. Replacing the cysteines with alanines did not change the solubility and stability of the monoclonal antibody, but binding to the antigen was significantly impaired. Three-dimensional modeling and dynamic simulations were employed to explore how the disulfide bridge influences the conformation of CDR-H3 and binding to the antigen. On the basis of these results, we envision that designing human combinatorial antibody libraries to contain intra-CDR or inter-CDR disulfide bridges could lead to identification of human antibodies with unique binding profiles.

Patterns of injury in geriatric falls.

Falls are the most common cause of trauma in the elderly. Data regarding patterns of injury following geriatric falls are scant. We conducted a retrospective review of falls in patients aged 65 years and older seen at a trauma center over a nine year period. Two thousand eighty three patients met the inclusion criteria. Hip fracture proved to be the dominant injury (55%), 98% of which were isolated. Five hundred seven (21%) were non-hip fractures. Two hundred thirty eight patients (10%) sustained traumatic intracranial hemorrhage. Chest injury was the next most common injury type (6.7%) with rib fractures comprising 86% of this subgroup. A pattern of association between intracranial hemorrhage and cervical spine fractures was identified. Intra-abdominal injuries are rare.

Vital capacity as a predictor of outcome in elderly patients with rib fractures.

BACKGROUND: This study tests the relationships between early bedside vital capacity (VC) measurement and morbidity, mortality, and resource consumption in geriatric blunt chest trauma patients with rib fractures. METHODS: This was a retrospective study examining all patients > or = 65 years old with rib fractures who had a VC measured within 48 hours of their emergency department evaluation. Outcome variables included pulmonary complications, death from pulmonary complications, hospital length of stay (LOS), intensive care unit length of stay (ICU LOS), and discharge disposition. RESULTS: Thirty-eight patients met the study criteria. The mean age was 80.2 (+/-7.4) years, the mean number of rib fractures was 3.6 (+/-1.6), and the mean ISS was 6.9 (+/-4.7). VC and the percentage of the predicted vital capacity (pVC) were both inversely correlated with LOS (p = 0.0076 and p = 0.0172, respectively). Linear regression analysis suggested that patients with a VC < 1.4 L or < 55% of their pVC had a LOS > 3 days. Mean VC was 36% higher in patients who were discharged home versus those discharged to an extended care facility (ECF; p = 0.025). There was a trend toward significance when comparing VC to ICU LOS (p = 0.079), but none in predicting pulmonary complications (p = 0.3299). No correlations between VC and mortality can be drawn given the single death in the cohort. CONCLUSIONS: Bedside VC is a simple measurement which could predict LOS in elderly patients with rib fractures and may identify those patients requiring ECF upon discharge. Further prospective study may highlight the utility of emergency room VC in determining the disposition of these patients.

Identification of ligands for two human bitter T2R receptors.

Earlier, a family of G protein-coupled receptors, termed T2Rs, was identified in the rodent and human genomes through data mining. It was suggested that these receptors mediate bitter taste perception. Analysis of the human genome revealed that the hT2R family is composed of 25 members. However, bitter ligands have been identified for only three human receptors so far. Here we report identification of two novel ligand-receptor pairs. hT2R61 is activated by 6-nitrosaccharin, a bitter derivative of saccharin. hT2R44 is activated by denatonium and 6-nitrosaccharin. Activation profiles for these receptors correlate with psychophysical data determined for the bitter compounds in human studies. Functional analysis of hT2R chimeras allowed us to identify residues in extracellular loops critical for receptor activation by ligands. The discovery of two novel bitter ligand-receptor pairs provides additional support for the hypothesis that hT2Rs mediate a bitter taste response in humans.