Regression of EGFR positive established solid tumors in mice with the conditionally active T cell engager TAK-186.

BACKGROUND: Despite clinical success with T cell engagers (TCEs) targeting hematological malignancies, achieving a safe and efficacious dose in patients with solid tumors remains challenging. Due to potency, low levels of target antigen expression on normal tissues may not be tolerated. To overcome this, we engineered a novel conditionally active TCE design called COBRA (Conditional Bispecific Redirected Activation). Administered as prodrugs, COBRAs bind to cell surface antigens on both normal and tumor tissues but are preferentially activated within the tumor microenvironment. METHODS: A COBRA was engineered to target EGFR, TAK-186. The potency of precleaved TAK-186 relative to a non-cleavable control was assessed in vitro. Mice bearing established solid tumors expressing a range of EGFR levels were administered a single bolus of human T cells, and concurrently treated with TAK-186 and associated controls intravenously. We assessed the plasma and tumor exposure of intact and cleaved TAK-186. RESULTS: TAK-186 shows potent redirected T cell killing of antigen expressing tumor cells. In vivo efficacy studies demonstrate regressions of established solid tumors, dependent on intratumoral COBRA cleavage. Pharmacokinetic studies reveal TAK-186 is stable in circulation, but once activated is rapidly cleared due to loss of its albumin-binding half-life extension domain. CONCLUSIONS: The studies shown support the advancement of TAK-186, and the pursuit of additional COBRA TCEs for the treatment of solid tumors.

TriTACs, a Novel Class of T-Cell-Engaging Protein Constructs Designed for the Treatment of Solid Tumors.

T cells have a unique capability to eliminate cancer cells and fight malignancies. Cancer cells have adopted multiple immune evasion mechanisms aimed at inhibiting T cells. Dramatically improved patient outcomes have been achieved with therapies genetically reprogramming T cells, blocking T-cell inhibition by cancer cells, or transiently connecting T cells with cancer cells for redirected lysis. This last modality is based on antibody constructs that bind a surface antigen on cancer cells and an invariant component of the T-cell receptor. Although high response rates were observed with T-cell engagers specific for CD19, CD20, or BCMA in patients with hematologic cancers, the treatment of solid tumors has been less successful. Here, we developed and characterized a novel T-cell engager format, called TriTAC (for Trispecific T-cell Activating Construct). TriTACs are engineered with features to improve patient safety and solid tumor activity, including high stability, small size, flexible linkers, long serum half-life, and highly specific and potent redirected lysis. The present study establishes the structure/activity relationship of TriTACs and describes the development of HPN424, a PSMA- (FOLH1-) targeting TriTAC in clinical development for patients with metastatic castration-resistant prostate cancer.

COBRA™: a highly potent conditionally active T cell engager engineered for the treatment of solid tumors.

Conditionally active COBRA™ (COnditional Bispecific Redirected Activation) T cell engagers are engineered to overcome the limitations of inherently active first-generation T cell engagers, which are unable to discern between tumor and healthy tissues. Designed to be administered as prodrugs, COBRAs target cell surface antigens upon administration, but engage T cells only after they are activated within the tumor microenvironment (TME). This allows COBRAs to be preferentially turned on in tumors while safely remaining inactive in healthy tissue. Here, we describe the development of the COBRA design and the characterization of these conditionally active T cell engagers. Upon administration COBRAs are engineered to bind to tumor-associated antigens (TAAs) and serum albumin (to extend their half-life in circulation), but are inhibited from interacting with the T cell receptor complex signaling molecule CD3. In the TME, a matrix metalloproteinase (MMP)-mediated linker cleavage event occurs within the COBRA construct, which rearranges the molecule, allowing it to co-engage TAAs and CD3, thereby activating T cells against the tumor. COBRAs are conditionally activated through cleavage with MMP9, and once active are highly potent, displaying sub-pM EC50s in T cell killing assays. Studies in tumor-bearing mice demonstrate COBRA administration completely regresses established solid tumor xenografts. These results strongly support the further characterization of the novel COBRA design in preclinical development studies.

Monoclonal antibody-mediated detection of CTX-M ß-lactamases in Gram-negative bacteria.

Gram-negative bacteria (GNB) that express CTX-M ß-lactamases have become a serious threat to the clinical management of GNB infections. While antibody-based platforms have been successfully used in research settings to study and detect other ß-lactamases-including SHV, CMY, and TEM enzymes-there is currently a lack of antibody-based tools to detect the CTX-M enzymes. Here we describe the development of an anti-CTX-M sandwich ELISA based on a pair of monoclonal antibodies (mAbs)-mAb 6101-33 and mAb 6101-19-used as the capture and detection antibody, respectively. This antibody pair detected CTX-M variants from group 1 (CTX-M-15), group 2 (CTX-M-2), group 8 (CTX-M-8), and group 9 (CTX-M-14) that were expressed by a training set of clinical GNB isolates. The limit of detection for this sandwich ELISA was 30ng of recombinant CTX-M-15, and CTX-Ms expressed by 106 lysed CFU of GNB. When tested against a blinded panel of 78 clinical isolates, the sandwich ELISA demonstrated a sensitivity of 96% and a specificity of 100%. The mAb pair did not cross-react with bacteria that contained other ß-lactamases, including TEM, SHV, OXA, KPC, NDM, CMY, and DHA. In conclusion, we developed a highly sensitive and specific sandwich ELISA, capable of detecting CTX-M enzyme production in GNB pathogens.

A rapid, inexpensive and disposable point-of-care blood test for sickle cell disease using novel, highly specific monoclonal antibodies.

Sickle cell disease (SCD) is a significant healthcare burden worldwide, but most affected individuals reside in low-resource areas where access to diagnostic testing may be limited. We developed and validated a rapid, inexpensive, disposable diagnostic test, the HemoTypeSC™ , based on novel monoclonal antibodies (MAbs) that differentiate normal adult haemoglobin (Hb A), sickle haemoglobin (Hb S) and haemoglobin C (Hb C). In competitive enzyme-linked immunosorbent assays, each MAb bound only its target with <0·1% cross-reactivity. With the HemoTypeSC™ test procedure, the sensitivity for each variant was <5·0 g/l. The accuracy of HemoTypeSC™ was evaluated on 100 whole blood samples from individuals with common relevant haemoglobin phenotypes, including normal (Hb AA, N = 20), carrier or trait (Hb AS, N = 22; Hb AC, N = 20), SCD (Hb SS, N = 22; Hb SC, N = 13), and Hb C disease (Hb CC, N = 3). The correct haemoglobin phenotype was identified in 100% of these samples. The accuracy of the test was not affected by Hb F (0-94·8% of total Hb) or Hb A2 (0-5·6% of total Hb). HemoTypeSC™ requires <1 µl of whole blood and no instruments or power sources. The total time-to-result is <20 min. HemoTypeSC™ may be a practical solution for point-of-care testing for SCD and carrier status in low-resource settings.

The Asian Grocery Store-Based Cancer Education Program: Creating New Education Modules.

Operating since 1994, the UCSD Moores Cancer Center's Asian Grocery Store-Based Cancer Education Program (the Program) is a proven and sustainable strategy for disseminating cancer and poison control information to Asian and Pacific Islander (API) communities. This paper describes the process taken to identify health topics that can be readily addressed within the Program's infrastructure and reports results of the pilot testing of the educational module that was developed by following that process. The development of each new module is guided by the Health Belief Model and the Tipping Point Model. The process starts with the selection of a health topic demonstrating pressing need and treatment options in the API community. Then, using the Pareto principle, reasonably modifiable risk factors are chosen to be addressed in the module. "Sticky messaging" for the modifiable risk factors is developed to package the health information as memorable and transmissible calls-to-action. Finally, grocery store outreaches were used to pilot test the new module to assess its effectiveness at facilitating health care information to API community members. By adhering to the steps described in this paper, the authors were able to: (1) select liver cancer as a pressing API health issue that could be positively impacted by the Program; (2) identify reasonably modifiable risk factors for the chosen health issue; (3) generate compelling call-to-action messages to decrease risk of exposure; and (4) demonstrate the cultural and linguistic alignment of the liver cancer control module. The development and testing of new health education modules follow a methodical process guided by scientific principles. Understanding and employing the elements of an existing evidence-based and sustainable health education program can increase the likelihood of success in addressing the health needs of the API community.

The RpoE Stress Response Pathway Mediates Reduction of the Virulence of Enteropathogenic Escherichia coli by Zinc.

Zinc supplements are an effective clinical treatment for infantile diarrheal disease caused by enteric pathogens. Previous studies demonstrated that zinc acts on enteropathogenic Escherichia coli (EPEC) bacteria directly to suppress several virulence-related genes at a concentration that can be achieved by oral delivery of dietary zinc supplements. Our in vitro studies showed that a micromolar concentration of zinc induced the envelope stress response and suppressed virulence in EPEC, providing a possible mechanistic explanation for zinc's therapeutic action. In this report, we investigated the molecular and physiological changes in EPEC induced by zinc. We found that micromolar concentrations of zinc reduced the bacterial growth rate without affecting viability. We observed increased membrane permeability caused by zinc. Zinc upregulated the RpoE-dependent envelope stress response pathway and suppressed EPEC virulence gene expression. RpoE alone was sufficient to inhibit virulence factor expression and to attenuate attaching and effacing lesion formation on human host cells. By mutational analysis we demonstrate that the DNA-binding motif of RpoE is necessary for suppression of the LEE1, but not the LEE4, operon. Predictably, inhibition of the RpoE-mediated envelope stress response in combination with micromolar concentrations of zinc reduced EPEC viability. In conclusion, zinc induces the RpoE and stress response pathways in EPEC, and the alternate sigma factor RpoE downregulates EPEC LEE and non-LEE virulence genes by multiple mechanisms.

Convergent and divergent dislocation of the pediatric elbow: two case reports and comprehensive review of literature.

Convergent and divergent pediatric elbow dislocations are rare injuries. When properly diagnosed and treated without delay, both types of dislocations have a good prognosis. We describe a case of convergent elbow dislocation in a 16-year-old boy. The patient underwent operative intervention and demonstrated full range of motion at the 4-year follow-up. Our second case describes an 11-year-old boy with a divergent elbow dislocation associated with an ipsilateral distal radius fracture and distal radioulnar joint dislocation. The patient showed full range of motion 1 year after closed reduction and casting and had no residual deformities or abnormalties.

Dorsal dislocation of the distal interphalangeal joint and volar dislocation of the metacarpophalangeal joint in the same finger: a case report.

Double dislocations of the finger interphalangeal and/or metacarpophalangeal joints are a rare entity. Sixty-four cases of distal and proximal interphalangeal joint double dislocations have been previously reported. Five cases of metacarpophalangeal and interphalangeal double dislocations of the thumb have also been reported. Only one case has been reported in the English literature regarding simultaneous dislocations of the distal interphalangeal and metacarpophalangeal joints in the nonthumb digit. The directions of the dislocation were the same; both were dorsal. We report, to our knowledge, the first ever case of a double dislocation a non-thumb digit in opposing directions-volar at the metacarpophalangeal joint and dorsal at the distal interphalangeal joint.

The Clinical Application of Kaplan's Cardinal Line as a Surface Marker for the Superficial Palmar Arch.

We feel the original description of Kaplan's cardinal line provides a more accurate reference point to the superficial palmar arterial arch. We sought to anatomically correlate the relationship of Kaplan's cardinal line to the superficial palmar arch. Sixty hands (30 cadavers) were dissected after Kaplan's original description was drawn on each hand. Measurements we made from Kaplan's cardinal line to the superficial palmar arch at both the radial and ulnar borders of the ring finger. The superficial palmar arterial arch was an average of 10.4 and 11.8 mm from the radial and ulnar borders of the ring finger with standard deviations of roughly 4 mm for each measurement. Clinically, Kaplan's cardinal line is a more predictable landmark for the superficial palmar arch. In referencing this landmark as the distal most extent of an open or endoscopic carpal tunnel release, the superficial palmar arch should be free of transection.

Comparison of fixation methods for scaphoid nonunions: a biomechanical model.

The purpose of this study was to analyze the relative bio- mechanical stability of three types of internal ixation with cancellous bone graft in a cadaveric, scaphoid nonunion model. A scaphoid nonunion model was created by remov- ing a volar wedge of bone from the waist of the scaphoid in 18 fresh frozen human cadavers. Cancellous sawbone graft was inserted into the osteotomy site and three groups of six cadavers each were then internally ixed with a pair of parallel 0.045-inch K-wires, Mini-Acutrak screws, or Standard Acutrak screws, respectively for each group. The potted specimens were tested using an Instron(R) tensile testing machine by applying force to the distal pole of the scaphoid. The load and stiffness were calculated at 2 mm and 4 mm of displacement. Results showed that both the Mini-Acutrak screw and the Standard Acutrak screw were statistically stronger and stiffer at 2 mm displacement than the pair of parallel 0.045-inch K-wires. No statistically sig- niicant difference between the Standard and Mini-Acutrak screws was noted at 2 mm displacement. At higher loads (4 mm displacement), the Standard Acutrak became statisti- cally stronger and stiffer than the Mini-Acutrak screw. It was concluded that the Standard Acutrak screw followed by the Mini-Acutrak screw may be a better option than a pair of parallel 0.045-inch K-wires when treating scaphoid nonunions. The screws have increased strength of ixation and stiffness when compared to K-wires. Also, unlike the K wires, the Acutrak screws enhance fracture healing by achieving interfragmentary compression. Even in a cancel- lous bone graft model, interfragmentary compression was achieved and our concern that the bone graft would "spit out" was allayed.

Fixation systems of greater trochanteric osteotomies: biomechanical and clinical outcomes.

The development of cerclage systems for fixation of greater trochanteric osteotomies has progressed from monofilament wires to multifilament cables to cable grip and cable plate systems. Cerclage wires and cables have various clinical indications, including fixation for fractures and for trochanteric osteotomy in hip arthroplasty. To achieve stable fixation and eventual union of the trochanteric osteotomy, the implant must counteract the destabilizing forces associated with pull of the peritrochanteric musculature. The material properties of cables and cable grip systems are superior to those of monofilament wires; however, potential complications with the use of cables include debris generation and third-body polyethylene wear. Nevertheless, the cable grip system provides the strongest fixation and results in lower rates of nonunion and trochanteric migration. Cable plate constructs show promise but require further clinical studies to validate their efficacy and safety.

A biomechanical comparison of the modified Mason-Allen stitch and massive cuff stitch in vitro.

PURPOSE: The suture-tendon interface is generally regarded as the weak link in rotator cuff fixation. High rates of failure in arthroscopic rotator cuff repair have led to a search for strong yet easy-to-perform suture configurations. The goal of this study was to compare the strength of 2 commonly used suture configurations, the modified Mason-Allen stitch and the massive cuff stitch, when suture-anchored into bone. METHODS: Fourteen sheep shoulders were harvested and the infraspinatus tendon isolated. Each infraspinatus tendon was split in half longitudinally along the axis of its fibers to yield 2 tendon-bone specimens per shoulder, for a total of 28 specimens. Each split tendon was then repaired by use of a double-loaded suture anchor with a modified Mason-Allen and simple suture in one specimen and the massive cuff stitch in the other. Each specimen was initially cyclically loaded on a vertical MTS uniaxial load frame (MTS Systems, Eden Prairie, MN) under force control from 5 to 30 N at 0.25 Hz for 20 cycles. Each specimen was then loaded to failure under displacement control at a rate of 1 mm/s. Peak-to-peak displacement, cyclic elongation, ultimate tensile load, stiffness, and mode of failure were recorded. A repeated-measures analysis of variance was performed, with an alpha level of significance set at P < .05. RESULTS: No statistically significant difference was found with regard to ultimate load to failure between the modified Mason-Allen stitch (110.4 +/- 55.1 N) and massive cuff stitch (116.4 +/- 37.9 N). In addition, no statistically significant difference was found with regard to cyclic elongation, peak-to-peak displacement, or initial displacement. The most common mode of failure for both suture configurations was suture pullout. CONCLUSIONS: The modified Mason-Allen stitch and massive cuff stitch yield similar biomechanical profiles when suture-anchored into bone. CLINICAL RELEVANCE: The massive cuff stitch may be a simpler and biomechanically equivalent alternative to the modified Mason-Allen stitch in arthroscopic rotator cuff repair.

Loss of total arc of motion in collegiate baseball players.

Published studies on asymptomatic athletes show an increase in external rotation and decrease in internal rotation while maintaining the total arc of motion of the glenohumeral joint. The purpose of this study was to determine whether overhand athletes with shoulder pain maintained their total arc of motion. Sixty-seven college-level baseball players were examined. Internal rotation and external rotation of the glenohumeral joint, measured at 90 degrees of abduction, and total arc of shoulder motion were compared between dominant and nondominant extremities in athletes with and without shoulder pain. Dominant shoulders in the pain group had a mean arc of 136.2 degrees compared with 145.8 degrees in the nondominant group, for a side-to-side difference of 9.6 degrees. We demonstrate that college-level baseball players with shoulder pain have a significant decrease in total arc of shoulder motion and internal rotation compared with their nondominant shoulder and with pain-free athletes.

Elbow fracture-dislocations: the role of hinged external fixation.

Fracture-dislocations of the elbow remain a complex problem in orthopaedics. The myriad of treatment protocols and methodologies focuses on precise articular alignment and restoration of the skeletal architecture. The goal is to re-establish function as quickly as possible so as to allow rehabilitation involving the full range of motion. Surgical management, primarily reconstruction of the secondary stabilizers of the elbow joint as well as preserving soft tissue structures, subsequently provides the possibility of a speedier recovery. If proper skeletal alignment does not confer enough stability, hinged external fixation becomes an integral part of the treatment strategy for the reconstructive and trauma surgeon.

A meta-analysis of the literature on distal radius fractures: review of 615 articles.

A structured meta-analysis of the available literature was performed to evaluate the outcome of the treatment of displaced intra-articular fractures of the distal radius. A comprehensive search of Medline using the key words "radius" and "fracture" revealed over 4,000 articles. After limiting the search to clinical trials in English and excluding pediatric and geriatric age groups as well as biomechanical and animal studies, 615 abstracts were identified in the period from 1976 to May 1998. Thirty-one articles met the inclusion and exclusion criteria. These included two prospective randomized comparative trials, two non-randomized comparative trials, one half prospective case series and half historical control, and 27 papers on case series. Four papers dealt with external fixation versus closed reduction and cast treatment and one paper looked at open reduction internal fixation with or without additional external fixation. There was insufficient data to perform a scientific meta-analysis because of the poor quality of the studies and lack of a uniform method of outcome assessment. However, the data from the comparative trials showed that external fixation was favored over closed reduction and casting. Additionally, comparing the results of the case series showed that external fixation was superior to internal fixation.