Ribociclib-induced liver injury: a case report

Background

Idiosyncratic drug-induced liver injury (DILI) is a rare, unpredictable hepatic adverse event and the most common cause of acute liver failure in Europe and the US. Ribociclib is a potent Cyclin-dependent kinase 4 and 6 (CDK4/6)-inhibitor administered for advanced hormone-receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative breast cancer. Previous reports have shown hepatotoxicity without liver necrosis related to ribociclib.

Case presentation

A 41-year-old female patient with primary metastatic HR-positive, HER2-negative breast cancer developed liver enzyme elevation under treatment with ribociclib. Ribociclib was withdrawn 8 weeks after initiation due to liver enzyme elevation. A liver biopsy, performed due to further enzyme increase (peak ALT 2836 U/l), onset of jaundice (peak bilirubin 353 µmol/l) and coagulopathy (INR 1.8) two weeks later, revealed acute hepatitis with 30% parenchymal necrosis. Roussel Uclaf Causality Assessment Method (RUCAM) score was 7 points (probable). Under treatment with prednisone (60mg), initiated 2 weeks after drug withdrawal, and subsequently N-acetylcysteine (Prescott regimen) liver enzymes normalized within 8 weeks along with prednisone tapering.

Conclusion

This case illustrates the development of a severe idiosyncratic hepatocellular pattern DILI grade 3 (International DILI Expert Working Group) induced by ribociclib. Routine liver enzyme testing during therapy, immediate hepatologic work-up and treatment interruption in case of liver enzyme elevation are highly recommended. Corticosteroid treatment should be considered in cases of severe necroinflammation.

Lateral cortical notching facilitates dynamization of proximal femoral nailing - A finite element analysis

INTRODUCTION

Dynamization of proximal femoral nailing by removal of distal interlocking is one of the recommended treatment options for nonunions of femur fractures. However, in certain inter-/subtrochanteric fractures, gliding of the nail along the femoral shaft is blocked by lateral femoral cortical support of the lag screw. For these cases, Biber et al. proposed lateral cortical notching (LCN), in which the supporting lateral bone is removed. This study investigates the biomechanical effect of LCN on gliding of proximal femoral nailing and stress distribution at the bone/implant interface.

MATERIALS AND METHODS

In this finite element analysis a three-dimensional model of an unstable intertrochanteric fracture with proximal femoral nailing without distal interlocking was simulated using the FebioStudio software suite. To simulate LCN, the lag screw hole was lengthened to 15.34 mm at the lateral cortex. Displacement of the nail along the femoral shaft axis and von Mises stress distribution were compared between LCN model and standard implantation model.

RESULTS

Displacement of the nail along the femoral shaft axis was higher in the LCN model than in the standard implantation model (0.48 mm vs. 0.07 mm). Highest von Mises stresses of 176-178 MPa at the implant and of 52-81 MPa at the proximal femur were detected. Maximum von Mises stresses of the implant were comparable at all sides, except for a reduced von Mises stress at the lateral inferior side in the LCN model (80 vs. 102 MPa). At the inferior lateral screw hole and the anterior/posterior lateral screw hole maximum von Mises stress was reduced in the LCN model (2 vs. 49 MPa and 52 vs. 81 MPa), whereas the maximum von Mises stress at the inferior medial screw hole was higher in the LCN model than in the standard implantation model (53 vs. 27 MPa).

CONCLUSIONS

Lateral cortical notching facilitates gliding of a distally dynamized proximal femoral nail along the femoral shaft axis in intertrochanteric fractures. Additionally, the lack of lateral cortical bone support at the lag screw reduces von Mises stress at the bone/implant interface and thus could lower the risk for implant breakage and peri‑implant fractures.

Drilling Sequence Optimization Using Evolutionary Algorithms to Reduce Heat Accumulation for Femtosecond Laser Drilling with Multi-Spot Beam Profiles

We report on laser drilling borehole arrays using ultrashort pulsed lasers with a particular focus on reducing the inadvertent heat accumulation across the workpiece by optimizing the drilling sequence. For the optimization, evolutionary algorithms are used and their results are verified by thermal simulation using Comsol and experimentally evaluated using a thermal imaging camera. To enhance process efficiency in terms of boreholes drilled per second, multi-spot approaches are employed using a spatial light modulator. However, as higher temperatures occur across the workpiece when using simultaneous multi-spot drilling as compared to a single-spot process, a subtle spatial distribution and sequence of the multi-spot approach has to be selected in order to limit the resulting local heat input over the processing time. Different optimization approaches based on evolutionary algorithms aid to select those drilling sequences which allow for the combination of a high efficiency of multi-spot profiles, a low-generated process temperature and a high-component quality. In particular, using a 4 × 4 laser spot array allows for the drilling of 40,000 boreholes in less than 76 s (526 boreholes/s) with a reduced temperature increase by about 35%, as compared to a single spot process when employing an optimized drilling sequence.

Toy story or children story? Putting children and their rights at the forefront of the artificial intelligence revolution

Policymakers need to start considering the impact smart connected toys (SCTs) have on children. Equipped with sensors, data processing capacities, and connectivity, SCTs targeting children increasingly penetrate pervasively personal environments. The network of SCTs forms the Internet of Toys (IoToys) and often increases children's engagement and playtime experience. Unfortunately, this young part of the population and, most of the time, their parents are often unaware of SCTs' far-reaching capacities and limitations. The capabilities and constraints of SCTs create severe side effects at the technical, individual, and societal level. These side effects are often unforeseeable and unexpected. They arise from the technology's use and the interconnected nature of the IoToys, without necessarily involving malevolence from their creators. Although existing regulations and new ethical guidelines for artificial intelligence provide remedies to address some of the side effects, policymakers did not develop these redress mechanisms having children and SCTs in mind. This article provides an analysis of the arising side effects of SCTs and contrasts them with current regulatory redress mechanisms. We thereby highlight misfits and needs for further policymaking efforts.

Optimization of Heat Accumulation during Femtosecond Laser Drilling Borehole Matrices by Using a Simplex Algorithm

We report on an optimization study of percussion drilling thin metal sheets employing a high repetition rate, high power femtosecond laser with respect to the resulting heat accumulation. A specified simplex algorithm was employed to optimize the spatial drilling sequence, whereas a simplified thermal simulation using COMSOL was validated by comparing its results to the temperature measurements using an infrared camera. Optimization for drilling borehole matrices was aspired with respect to the generated temperature across the processed specimen, while the drilling strategy was altered in its spatial drilling sequence and by using multi-spot approaches generated by a spatial light modulator. As a result, we found that an optimization strategy based on limited consecutive holes in a Moore neighborhood led to reduced temperatures and the shortest process times.

Iliotibial band autograft is a suitable alternative graft for anterior cruciate ligament reconstruction: a systematic review and meta-analysis of outcomes

PURPOSE

Despite encouraging clinical, biomechanical and histological results, ACL reconstruction using the ITB was slowly abandoned. The hypothesis was that the current literature supports the use of ITB as the graft of choice for ACL reconstruction because of its good outcomes.

METHODS

A systematic search of the literature was performed in the PubMed, MEDLINE, Cochrane, and Ovid databases to identify published clinical studies relevant to ACL reconstruction with ITB autograft and studies comparing ITB autograft with bone-patellar tendon-bone (BPTB) and hamstring (HT) autografts (none were found). The results of the eligible studies were analyzed in terms of graft failure, instrumented knee laxity measurements, Lachman test, pivot-shift test, Lysholm score, objective and subjective International Knee Documentation committee (IKDC) scores, Tegner activity score, return to sports rate, return to sports at pre-injury level and complications.

RESULTS

Nineteen clinical studies including 1,210 patients with ACL reconstruction met the inclusion criteria. Graft failure occurred after ITB autograft in 4.2% of patients. Postoperative mean side-to-side laxity was 1.41 mm with 21% of patients having greater than 3 mm side-to-side difference. Lachman test and pivot-shift test were negative (grade 0) in 57% and 85%, respectively, and were grade 0 or 1 in 95% and 97%, respectively. Functional outcomes were satisfactory in 84% of patients with good to excellent results (Lysholm score > 84). Mean postoperative Lysholm score was 93.3 and 84% of patients had an objective IKDC grade of A or B. Mean postoperative Tegner score was 6.8. The return to sports rate was 89% and 61% of patients returned to their pre-injury level. A comparison of 89 ITB versus 80 BPTB autografts revealed no significant differences in graft failure (n.s.), instrumented mean side-to-side knee laxity difference (n.s.) or Tegner score (n.s.).

CONCLUSION

The graft survival rate and clinical and functional outcomes for ITB autograft are satisfactory. By allowing ACL reconstruction and lateral tenodesis to be done with a single, continuous, pedicled graft through an outside-in femoral tunnel, this technique may become the preferred alternative for primary or secondary ACL surgery.

LEVEL OF EVIDENCE

Level IV.

Biomechanical in vitro analysis of a novel flexible implant for pubic symphysis disruption using an ultra-high molecular weight polyethylene fiber cord

BACKGROUND

Plate osteosynthesis depicts the gold standard to surgically treat pubic symphysis disruptions. However, high rates of implant failure after plate osteosynthesis are reported, probably because of the iatrogenic arthrodesis of this fibrocartilaginous joint. Therefore, flexible implants for treatment of pubic symphysis disruptions appear to be a sensible solution.

METHODS

In this biomechanical screening study, we designed and investigated a flexible implant, which consists of two plates connected with an ultra-high molecular weight polyethylene fiber cord. We mechanically tested eye splices as a possible fixation method of the cords by performing tensile load to failure tests. Afterwards, we developed a biomechanically appropriate plate design and cord routing between the plates. Finally, we biomechanically tested the flexible implant under tensile and shear loading until failure.

FINDINGS

When fixing a 1 mm ultra-high molecular weight polyethylene fiber cord with eye splices, a load at failure of 1570.74 N was detected under tensile loading. None of the eye splices failed but the cords itself ruptured. The load at failure of the designed cord routing in criss-cross technique and fixation within the plates amounts 4742.09 N under tensile and 2699.77 N under shear load.

INTERPRETATION

We developed a novel flexible implant for repair of pubic symphysis disruptions using ultra-high molecular weight polyethylene fiber cords connected to osteosynthesis plates. We identified eye splices as a mechanically optimal fixation method and proved that the ultra-high molecular weight polyethylene fiber cord routing and fixation of the flexible implant clearly withstands physiological forces acting on the pubic symphysis.

Determination of the through-plane profile of vanadium species in hydrated Nafion studied with micro X-ray absorption near-edge structure spectroscopy - proof of concept

Vanadium-ion transport through the polymer membrane results in a significant decrease in the capacity of vanadium redox flow batteries. It is assumed that five vanadium species are involved in this process. Micro X-ray absorption near-edge structure spectroscopy (micro-XANES) is a potent method to study chemical reactions during vanadium transport inside the membrane. In this work, protocols for micro-XANES measurements were developed to enable through-plane characterization of the vanadium species in Nafion 117 on beamline P06 of the PETRA III synchrotron radiation facility (DESY, Hamburg, Germany). A Kapton tube diffusion cell with a diameter of 3 mm was constructed. The tube diameter was chosen in order to accommodate laminar flow for cryogenic cooling while allowing easy handling of the cell components by hand. A vertical step size of 2.5 µm and a horizontal step size of 5 µm provided sufficient resolution to resolve the profile and good statistics after summing up horizontal rows of scan points. The beam was confined in the horizontal plane to account for the waviness of the membrane. The diffusion of vanadium ions during measurement was inhibited by the cryogenic cooling. Vanadium oxidation, e.g. by water radiolysis (water percentage in the hydrated membrane ∼23 wt%), was mitigated by the cryogenic cooling and by minimizing the dwell time per pixel to 5 ms. Thus, the photo-induced oxidation of V3+ in the focused beam could be limited to 10%. In diffusion experiments, Nafion inside the diffusion cell was exposed on one side to V3+ electrolyte and on the other side to VO2+. The ions were allowed to diffuse across the through-plane orientation of the membrane during one of two short defrost times (200 s and 600 s). Subsequent micro-XANES measurements showed the formation of VO2+ from V3+ and VO2+ inside the water body of Nafion. This result proves the suitability of the experimental setup as a powerful tool for the determination of the profile of vanadium species in Nafion and other ionomeric membranes.

Analysis of the optical properties of the silvery spots on the wings of the Gulf Fritillary, Dione vanillae

The ventral face of the wings of the butterfly Dione vanillae is covered with bright and shiny silvery spots. These areas contain densely packed ground- and coverscales with a bright metallic appearance reflecting more than 50% of light uniformly over the visible range. Our analysis shows that this optically attractive feature is caused by the inner microstructure of the scales located in these areas. Electron microscopy of cross sections through the scales shows that upper and lower lamina, supporting trabeculae, and topping ridges can be approximated by a 'circus tent'-like geometry. By simulating its optical properties, we show that a moderate disorder of this geometry is important for the uniform reflection of light resulting in the silvery appearance.

Iodine-Mediated Tryptathionine Formation Facilitates the Synthesis of Amanitins

Synthetic methods on the macrocyclization of peptides are of high interest since they facilitate the synthesis of various types of potentially bioactive compounds, e.g. addressing targets like protein-protein-interactions. Herein, we report on an efficient method to construct tryptathionine-cross-links in peptides between the amino acids Trp and Cys. This reaction not only is the basis for the total synthesis of the death cap toxin α-amanitin but also provides rapid access to various new amanitin analogues. This study for the first time presents a systematic compilation of structure-activity relations (SAR) of amatoxins with regard to RNA polymerase II inhibition and cytotoxicity with one amanitin derivative of superior RNAP II inhibition. The present approach paves the way for the synthesis of structurally diverse amatoxins as future payloads for antibody-toxin conjugates in cancer therapy.

Characterization of Dimeric Vanadium Uptake and Species in Nafion™ and Novel Membranes from Vanadium Redox Flow Batteries Electrolytes

A core component of energy storage systems like vanadium redox flow batteries (VRFB) is the polymer electrolyte membrane (PEM). In this work, the frequently used perfluorosulfonic-acid (PFSA) membrane Nafion™ 117 and a novel poly (vinylidene difluoride) (PVDF)-based membrane are investigated. A well-known problem in VRFBs is the vanadium permeation through the membrane. The consequence of this so-called vanadium crossover is a severe loss of capacity. For a better understanding of vanadium transport in membranes, the uptake of vanadium ions from electrolytes containing V_dimer(IV–V) and for comparison also V(II), V(III), V(IV), and V(V) by both membranes was studied. UV/VIS spectroscopy, X-ray absorption near edge structure spectroscopy (XANES), total reflection X-ray fluorescence spectroscopy (TXRF), inductively coupled plasma optical emission spectrometry (ICP-OES), and micro X-ray fluorescence spectroscopy (microXRF) were used to determine the vanadium concentrations and the species inside the membrane. The results strongly support that V_dimer(IV–V), a dimer formed from V(IV) and V(V), enters the nanoscopic water-body of Nafion™ 117 as such. This is interesting, because as of now, only the individual ions V(IV) and V(V) were considered to be transported through the membrane. Additionally, it was found that the V_dimer(IV–V) dimer partly dissociates to the individual ions in the novel PVDF-based membrane. The V_dimer(IV–V) dimer concentration in Nafion™ was determined and compared to those of the other species. After three days of equilibration time, the concentration of the dimer is the lowest compared to the monomeric vanadium species. The concentration of vanadium in terms of the relative uptake λ = n(V)/n(SO₃) are as follows: V(II) [λ = 0.155] > V(III) [λ = 0.137] > V(IV) [λ = 0.124] > V(V) [λ = 0.053] > V_dimer(IV–V) [λ = 0.039]. The results show that the V_dimer(IV–V) dimer needs to be considered in addition to the other monomeric species to properly describe the transport of vanadium through Nafion™ in VRFBs.

HDP-101, an Anti-BCMA Antibody-Drug Conjugate, Safely Delivers Amanitin to Induce Cell Death in Proliferating and Resting Multiple Myeloma Cells

Despite major treatment advances in recent years, patients with multiple myeloma inevitably relapse. The RNA polymerase II complex has been identified as a promising therapeutic target in both proliferating and dormant cancer cells. Alpha-amanitin, a toxin so far without clinical application due to high liver toxicity, specifically inhibits this complex. Here, we describe the development of HDP-101, an anti-B-cell maturation antigen (BCMA) antibody conjugated with an amanitin derivative. HDP-101 displayed high efficacy against both proliferating and resting myeloma cells in vitro, sparing BCMA-negative cells. In subcutaneous and disseminated murine xenograft models, HDP-101 induced tumor regression at low doses, including durable complete remissions after a single intravenous dose. In cynomolgus monkeys, HDP-101 was well tolerated with a promising therapeutic index. In conclusion, HDP-101 safely and selectively delivers amanitin to myeloma cells and provides a novel therapeutic approach to overcome drug resistance in this disease.

Variation of the frictional anisotropy on ventral scales of snakes caused by nanoscale steps

The ventral scales of most snakes feature micron-sized fibril structures with nanoscale steps oriented towards the snake's tail. We examined these structures by microtribometry as well as atomic force microscopy (AFM) and observed that the nanoscale steps of the micro-fibrils cause a frictional anisotropy, which varies along the snake's body in dependence of the height of the nanoscale steps. A significant frictional behavior is detected when a sharp AFM tip scans the nanoscale steps up or down. Larger friction peaks appear during upward scans (tail to head direction), while considerably lower peaks are observed for downward scans (head to tail direction). This effect causes a frictional anisotropy on the nanoscale, i.e. friction along the head to tail direction is lower than in the opposite direction. The overall effect increases linearly with the step height of the micro-fibrils. Although the step heights are different for each snake, the general step height distribution along the body of the examined snakes follows a common pattern. The frictional anisotropy, induced by the step height distribution, is largest close to the tail, intermediate in the middle, and lower close to the head. This common distribution of frictional anisotropy suggests that snakes even optimized nanoscale features like the height of micro-fibrils through evolution in order to achieve optimal friction performance for locomotion. Finally, ventral snake scales are replicated by imprinting their micro-fibril structures into a polymer. As the natural prototype, the artificial surface exhibits frictional anisotropy in dependence of the respective step height. This feature is of high interest for the design of tribological surfaces with artificial frictional anisotropy.

Amatoxins as RNA Polymerase II Inhibiting Antibody–Drug Conjugate (ADC) Payloads

Amatoxins are a group of natural toxins which occur in the death cap mushroom (Amanita phalloides). They work by inhibiting RNA polymerase II, which results in apoptosis. RNA-polymerase II inhibition is a novel mechanism of action in cancer therapy and offers the possibility of breaking through drug resistance or destroying dormant tumour cells, which could produce major clinical advances. Amanitin, as the most potent member of this toxin family, has been made accessible for cancer therapy by developing it as a payload for antibody–drug conjugates (ADCs). This chapter describes the discovery and chemistry of the amatoxins, and the development of the amanitin-ADC technology.

Abstract 237: Preclinical evaluation of anti-HER2 Antibody Targeted Amanitin Conjugates (ATACs) on HER2low breast cancer with chromosome 17p deletion

Background:

Triple negative breast cancer (TNBC) is the most difficult to treat subtype of breast cancer with limited therapeutic options. At least 50% of TNBC patients have low epidermal growth factor receptor 2 (HER2; ERBB2) expression with the majority harboring hemizygous loss of POLR2A/chromosome 17p. For these patients the treatment with antibody-targeted amanitin conjugates (ATACs) targeting HER2 is a new promising approach. ATACs comprise a new class of antibody-drug conjugates (ADCs) using amanitin as toxic payload and are able to kill antigen low expressing cells. Amanitin binds to the eukaryotic RNA polymerase II and thereby efficiently inhibits the cellular transcription process. In the current study, in vitro and in vivo data of ATACs targeting human HER2low as well as tolerability studies are presented. HER2low TNBC is considered an interesting target for amanitin-based ADCs.

Material and methods:

Different HER2 expressing cell lines were treated with anti-HER2 ATACs. Cysteine reactive amanitin-linkers were conjugated site-specifically to engineered cysteine residues of an anti-HER2 antibody yielding ATACs with a DAR of 2.0. Quantitative determination of cell viability was analyzed by BrdU ELISA assay. Subcutaneous mouse xenograft models with HER2-positive cell lines were performed with single-dose treatments. In addition, ATAC efficacy was tested in HER2low heterogeneous TNBC patient derived xenograft (PDX) models with and without POLR2A deletion. Tolerability of ATACs was assessed in mice and non-human primates (NHP).

Results:

Anti-HER2 ATACs showed in vitro cytotoxicity on HER2+ high and low cell lines in low nanomolar to picomolar range. In mouse xenograft models, the anti-HER2 ATACs caused dose-dependent tumor regression independent of Her2 expression level. In HER2low heterogeneous TNBC PDX models anti-HER2 ATACs caused dose-dependent tumor regression. The efficacy of anti-Her2 ATACs was more pronounced in PDX models with hemizygous loss of TP53 and POLR2A reflecting a 17p deletion. Safety profiling of an optimized anti-Her2 ATAC in cynomolgus monkeys revealed a good tolerability indicating a good therapeutic window for 17p deleted TNBC.

Conclusions:

Targeted cytotoxic drug delivery to HER2 positive cell lines was achieved by using anti-HER2 ATACs. The mode of action of the payload amanitin led to an efficient anti-tumor potential in vitro and in vivo with good tolerability in NHP studies. TNBC PDX models with HER2low expression were sensitive to ATAC treatment. Loss of POLR2A/chromosome 17p increased susceptibility to anti-HER2 ATAC making 17p del TNBC a suitable indication for optimized anti Her2 ATACs.

Citation Format: Christian Breunig, Anikó Pálfi, Michael Kulke, Christian Lutz, Christoph Müller, Torsten Hechler, Andreas Pahl. Preclinical evaluation of anti-HER2 Antibody Targeted Amanitin Conjugates (ATACs) on HER2low breast cancer with chromosome 17p deletion [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 237.

Locally Controlled Growth of Individual Lambda-Shaped Carbon Nanofibers

The locally defined growth of carbon nanofibers with lambda shape in an open flame process is demonstrated. Via the growth time, the geometry of the structures can be tailored to a Λ- or λ-type shape. Microchannel cantilever spotting and dip-pen nanolithography are utilized for the deposition of catalytic salt NiCl₂ · 6H₂ O for locally controlled growth of lambda-shaped carbon nanofibers. Rigorous downscaling reveals a critical catalytic salt volume of 0.033 µm³, resulting in exactly one lambda-shaped carbon nanofiber at a highly predefined position. An empirical model explains the observed growth process.

In vitro and in vivo studies of the ALS-FTLD protein CHCHD10 reveal novel mitochondrial topology and protein interactions

Mutations in coiled-coil-helix-coiled-coil-helix-domain containing 10 (CHCHD10), a mitochondrial twin CX9C protein whose function is still unknown, cause myopathy, motor neuron disease, frontotemporal dementia, and Parkinson's disease. Here, we investigate CHCHD10 topology and its protein interactome, as well as the effects of CHCHD10 depletion or expression of disease-associated mutations in wild-type cells. We find that CHCHD10 associates with membranes in the mitochondrial intermembrane space, where it interacts with a closely related protein, CHCHD2. Furthermore, both CHCHD10 and CHCHD2 interact with p32/GC1QR, a protein with various intra and extra-mitochondrial functions. CHCHD10 and CHCHD2 have short half-lives, suggesting regulatory rather than structural functions. Cell lines with CHCHD10 knockdown do not display bioenergetic defects, but, unexpectedly, accumulate excessive intramitochondrial iron. In mice, CHCHD10 is expressed in many tissues, most abundantly in heart, skeletal muscle, liver, and in specific CNS regions, notably the dopaminergic neurons of the substantia nigra and spinal cord neurons, which is consistent with the pathology associated with CHCHD10 mutations. Homozygote CHCHD10 knockout mice are viable, have no gross phenotypes, no bioenergetic defects or ultrastructural mitochondrial abnormalities in brain, heart or skeletal muscle, indicating that functional redundancy or compensatory mechanisms for CHCHD10 loss occur in vivo. Instead, cells expressing S59L or R15L mutant versions of CHCHD10, but not WT, have impaired mitochondrial energy metabolism. Taken together, the evidence obtained from our in vitro and in vivo studies suggest that CHCHD10 mutants cause disease through a gain of toxic function mechanism, rather than a loss of function.

Severity of local inflammation does not impact development of fibrosis in mouse models of intestinal fibrosis

Intestinal fibrosis is thought to be a consequence of excessive tissue repair, and constitutes a common problem in patients with Crohn’s disease (CD). While fibrosis seems to require inflammation as a prerequisite it is unclear whether the severity or persistence of inflammation influences the degree of fibrosis. Our aim was to investigate the role of sustained inflammation in fibrogenesis. For the initiation of fibrosis in vivo the models of Il10^−/− spontaneous colitis, dextran sodium sulfate (DSS)-induced chronic colitis and heterotopic transplantation were used. In Il10^−/− mice, we determined a positive correlation between expression of pro-inflammatory factors (Il1β, Tnf, Ifnγ, Mcp1 and Il6). We also found a positive correlation between the expression of pro-fibrotic factors (Col3a1 Col1a1, Tgfβ and αSma). In contrast, no significant correlation was determined between the expression of pro-inflammatory Tnf and pro-fibrotic αSma, Col1a1, Col3a1, collagen layer thickness and the hydroxyproline (HYP) content. Results from the DSS-induced chronic colitis model confirmed this finding. In the transplantation model for intestinal fibrosis a pronounced increase in Mcp1, inos and Il6 in Il10^−/− as compared to WT grafts was observed, indicating more severe inflammation in Il10^−/− grafts. However, the increase of collagen over time was virtually identical in both Il10^−/− and WT grafts. Severity of inflammation during onset of fibrogenesis did not correlate with collagen deposition. Although inflammation might be a pre-requisite for the initiation of fibrosis our data suggest that it has a minor impact on the progression of fibrosis. Our results suggest that development of fibrosis and inflammation may be disconnected. This may be important for explaining the inefficacy of anti-inflammatory treatments agents in most cases of fibrotic inflammatory bowel diseases (IBD).

Characterization of the microscopic tribological properties of sandfish (Scincus scincus) scales by atomic force microscopy

Lizards of the genus Scincus are widely known under the common name sandfish due to their ability to swim in loose, aeolian sand. Some studies report that this fascinating property of sandfish is accompanied by unique tribological properties of their skin such as ultra-low adhesion, friction and wear. The majority of these reports, however, is based on experiments conducted with a non-standard granular tribometer. Here, we characterise microscopic adhesion, friction and wear of single sandfish scales by atomic force microscopy. The analysis of frictional properties with different types of probes (sharp silicon tips, spherical glass tips and sand debris) demonstrates that the tribological properties of sandfish scales on the microscale are not exceptional if compared to snake scales or technical surfaces such as aluminium, Teflon, or highly oriented pyrolytic graphite.

Amanitins and their development as a payload for antibody-drug conjugates

Amanitin-based ADCs represent a new class of ADCs using a novel mode of action. This payload introduces a novel mode of action into oncology therapy, the inhibition of RNA Polymerase II. The high potency of the toxin leads to highly efficacious ADCs. The development of the technology around this toxin will be described. These developments support the clinical development of amanitin-based ADCs by using a toxin with a new mode of action and with a favorable therapeutic index. HDP-101 is an Amanitin based ADC directed against BCMA and will be advancing to the clinical phase in 2019.

[The usefulness of nasal provocation tests for respiratory physicians]

Rhinitis and asthma are common diseases that are strongly linked from both the epidemiological and patho-physiological point of view. A precise aetiological diagnosis is required in order to optimize treatment. Nasal provocation tests (NPT) determine precisely the role of the allergen in the initiation of the symptoms of rhinitis particularly when the history does not produce convincing evidence of the clinical relevance of an allergen. It may also have important consequences for the choice of an allergenic immunotherapy. NPT are not standardized but simple methods based on international recommendations provide us with good diagnostic accuracy. In this paper, we will discuss the practical aspects of NPT as well as the clinical or research situations where they may be useful for the respiratory physician.

Abstract 740: Preclinical evaluation of an anti-PSMA antibody-targeted amanitin conjugate (ATAC)

Background:

ATACs (antibody-targeted Amanitin conjugates) comprise a new class of antibody-drug conjugates using Amanitin as toxic payload. Amanitin binds to the eukaryotic RNA pol II and thereby inhibits the cellular transcription process at very low concentrations. In the current study, in vitro and in vivo data of an ATAC targeting PSMA (prostate specific membrane antigen) are presented. PSMA is predominantly expressed on malignant prostate cells in prostate carcinoma and correlates with tumor progression. Hence it is considered an interesting target for Amanitin based ADCs.

Material and methods:

PSMA cell lines: MDA-PCA-2B, LnCap. PC3 cell line served as PSMA negative control.

Antibody: humanized anti-PSMA and cysteine engineered monoclonal antibody (Albert Ludwig University Freiburg, medical center; humanization at Lonza Group AG, derivatization and production at Heidelberg Pharma).

Toxic warhead: A cysteine reactive amanitin-linker was conjugated site-specifically to engineered cysteine residues of the anti-PSMA antibody yielding an ATAC with a DAR of 2.0.

Cell proliferation assay: Quantitative determination of cell viability was performed by CellTiter Glo 2.0 assay (Promega).

Animal models: Subcutaneous Mouse xenograft tumor models with PSMA-positive cell lines MDA-PCA-2B and LnCap were performed in single-dose and multiple-dosing experiments. Tolerability was assessed in mice and non-human primates (NHP).

Results:

The anti-PSMA ATAC showed in vitro cytotoxicity on PSMA+ cell lines in picomolar range, whereas no cytotoxic activity on PSMA- cells was observed.

In mouse xenograft models, the anti-PSMA ATAC caused dose-dependent tumor regression. Complete remission was achieved after a single i.v. dose of 4.0 mg/kg and after repeated i.v. doses of 2.0 mg/kg in s.c. xenografts.

Safety profiling in Cynomolgus monkeys revealed a good tolerability and therapeutic index after sequentially applied doses of 0.3, 1.0 and 3.0 mg/kg. Hematology and clinical chemistry parameters were unaffected except liver enzymes and LDH: A moderate and transient increase was observed. The half-life of the ATAC in serum was 7-10 days; the free toxin was detectable at levels close to the lower limit of quantification only (LLOQ = 1.2 nM).

Conclusions:

Targeted cytotoxic drug delivery to PSMA positive prostate cancer cell lines was achieved by using an anti-PSMA ATAC. The mode of action of the payload Amanitin led to an efficient anti-tumor potential in vitro and in vivo with good tolerability in NHP studies. The use of ATACs in the therapy of PSMA positive prostate cancer is a promising approach, especially by using a cytotoxic agent whose mode of action differs from other commonly used toxins.

Citation Format: Anikó Pálfi, Christian Breunig, Torsten Hechler, Christoph Müller, Christian Lutz, Andreas Pahl, Michael Kulke. Preclinical evaluation of an anti-PSMA antibody-targeted amanitin conjugate (ATAC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 740.

Abstract 735: SAR of amanitin and optimization of linker-amanitin derivatives for solid tumors

Background:

ATACs (Antibody Targeted Amanitin Conjugates) comprise a new class of antibody-drug conjugates using amanitin as toxic payload. Amanitin binds to the eukaryotic RNA pol II and thereby inhibits the cellular transcription process at very low concentrations. We accomplished the chemical synthesis of amanitin and were able to synthesize amanitin variants in order to optimize the toxin structure for different tumors and antibodies. We will present in vitro and in vivo data of eight different linker-amanitin constructs attached to three different antibodies targeting solid tumors.

Material and methods:

Cell lines: JIMT-1, SKBR-3, BT474 and NCI-N87 (used for anti-Her-2-ATACs); LnCap, 22RV1, MDA-PCa2b and C4.2 (used for anti-PSMA-ATACs); Raji, Raji Luc, Nalm-6 and MEC-2 (used for anti-CD19-ATACs)

Antibodies: Anti-Her-2 (cysteine engineered monoclonal antibody, Heidelberg Pharma); humanized anti-PSMA (Albert Ludwig University Freiburg, medical center; humanization at Lonza Group AG; cysteine engineered monoclonal antibody, Heidelberg Pharma); chimeric anti-CD19 (DKFZ Heidelberg, Germany; cysteine engineered monoclonal antibody, Heidelberg Pharma).

Toxic warhead: Cysteine reactive linker-amanitin constructs were synthesized at Heidelberg Pharma and conjugated site-specifically to the antibodies.

Cell proliferation assay: Quantitative determination of cell viability was performed by CellTiter Glo 2.0 assay (Promega).

Animal models: Subcutaneous Mouse xenograft tumor models (Her-2-, PSMA- and CD19-positive cell lines) were performed in single-dose experiments. Tolerability was assessed in mice and will be assessed in non-human primates (NHP).

Results:

Eight different amanitin-linker constructs were synthesized. They differed in the attachment site of the linker at the amanitin as well as in the toxin core structure. All ATACs showed in vitro cytotoxicity on target positive cell lines in the picomolar range.

In mouse xenograft models, ATACs with four of the eight linker-amanitin derivatives caused dose-dependent tumor regression and complete remission after a single i.v. dose of 2.0 mg/kg in s.c. xenografts irrespective of the antibody and target used. In contrast the other four linker-amanitin derivatives were only poorly effective in vivo while showing comparable in vitro activities. When comparing subcutaneous and intravenous xenograft models using the same cancer cell line, the different efficacy of the eight linker-amanitin variants was only detected in subcutaneous but not in intravenous xenografts. Mouse tolerability studies of ATACs showed a MTD of at least 10mg/kg for all linker-amanitin variants.

Conclusions:

Different efficacy of linker-amanitin derivatives with regard to mouse xenograft models was detected. An SAR profile of amanitin could be established which enabled the selection of optimized linker-amanitin variants for the use of ATACs in solid tumors.

Citation Format: Michael Kulke, Anikó Pálfi, Christoph Müller, Werner Simon, Susanne Werner-Simon, Christian Lutz, Torsten Hechler, Andreas Pahl. SAR of amanitin and optimization of linker-amanitin derivatives for solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 735.

Percutaneous Medial Ligament Reconstruction for Valgus Knee Instability

Injuries to stabilizing elements on the medial side of the knee are one of the most common knee ailments. Because of the good healing capacity of these structures, acute injuries are typically treated conservatively. However, valgus laxity near full extension can persist in some patients. This laxity may be the source of instability due to medial joint space opening, which then requires surgical treatment. Various procedures have been described that aim to reproduce the anatomy of the medial collateral ligament (MCL) and the posterior oblique ligament (POL), which work together to stabilize the medial aspect of the knee. However, these are complex open surgical procedures, technically demanding to achieve the favorable isometry, which prevent joint contracture or recurrence of laxity. The purpose of this study was to describe a short construct that minimizes the risk of secondary loss of tension and complies with the principle of favorable anisometry. The graft is positioned in the joint opening axis, between the deep bundle of the MCL and the POL.

Exocrine pancreas glutamate secretion help to sustain enterocyte nutritional needs under protein restriction

Glutamine (Gln) is the most concentrated amino acid in blood and considered conditionally essential. Its requirement is increased during physiological stress, such as malnutrition or illness, despite its production by muscle and other organs. In the malnourished state, Gln has been suggested to have a trophic effect on the exocrine pancreas and small intestine. However, the Gln transport capacity, the functional relationship of these two organs, and the potential role of the Gln-glutamate (Glu) cycle are unknown. We observed that pancreatic acinar cells express lower levels of Glu than Gln transporters. Consistent with this expression pattern, the rate of Glu influx into acinar cells was approximately sixfold lower than that of Gln. During protein restriction, acinar cell glutaminase expression was increased and Gln accumulation was maintained. Moreover, Glu secretion by acinar cells into pancreatic juice and thus into the lumen of the small intestine was maintained. In the intestinal lumen, Glu absorption was preserved and Glu dehydrogenase expression was augmented, potentially providing the substrates for increasing energy production via the TCA cycle. Our findings suggest that one mechanism by which Gln exerts a positive effect on exocrine pancreas and small intestine involves the Gln metabolism in acinar cells and the secretion of Glu into the small intestine lumen. The exocrine pancreas acinar cells not only avidly accumulate Gln but metabolize Gln to generate energy and to synthesize Glu for secretion in the pancreatic juice. Secreted Glu is suggested to play an important role during malnourishment in sustaining small intestinal homeostasis. NEW & NOTEWORTHY Glutamine (Gln) has been suggested to have a trophic effect on exocrine pancreas and small intestine in malnourished states, but the mechanism is unknown. In this study, we suggest that this trophic effect derives from an interorgan relationship between exocrine pancreas and small intestine for Gln-glutamate (Glu) utilization involving the uptake and metabolism of Gln in acinar cells and secretion of Glu into the lumen of the small intestine.

Dry adhesives from carbon nanofibers grown in an open ethanol flame

Based on magnetic-field-assisted growth of carbon nanofibers in an open ethanol flame we fabricated arrays of carbon nanofibers with different degrees of orientation. Inspired by the dry adhesive system of geckos we investigated the adhesive properties of such carbon nanofiber arrays with ordered and random orientation. AFM-based force spectroscopy revealed that adhesion force and energy rise linear with preload force. Carbon nanofibers oriented by a magnetic field show a 68% higher adhesion (0.66 N/cm²) than the randomly oriented fibers. Endurance tests revealed that the carbon nanofiber arrays withstand 50.000 attachment/detachment cycles without observable wear.

Myeloid differentiation primary response gene (MyD) 88 signalling is not essential for intestinal fibrosis development

Dysregulation of the immune response to microbiota is associated with inflammatory bowel disease (IBD), which can trigger intestinal fibrosis. MyD88 is a key component of microbiota signalling but its influence on intestinal fibrosis has not been clarified. Small bowel resections from donor-mice were transplanted subcutaneously into the neck of recipients C57BL/6 B6-MyD88tm1 Aki (MyD88^-/-) and C57BL/6-Tg(UBC-green fluorescence protein (GFP))30Scha/J (GFP-Tg). Grafts were explanted up to 21 days after transplantation. Collagen layer thickness was determined using Sirius Red stained slides. In the mouse model of fibrosis collagen deposition and transforming growth factor-beta 1 (TGF-β1) expression was equal in MyD88^+/+ and MyD88^-/-, indicating that MyD88 was not essential for fibrogenesis. Matrix metalloproteinase (Mmp)9 expression was significantly decreased in grafts transplanted into MyD88^-/- recipients compared to MyD88^+/+ recipients (0.2 ± 0.1 vs. 153.0 ± 23.1, respectively, p < 0.05), similarly recruitment of neutrophils was significantly reduced (16.3 ± 4.5 vs. 25.4 ± 3.1, respectively, p < 0.05). Development of intestinal fibrosis appears to be independent of MyD88 signalling indicating a minor role of bacterial wall compounds in the process which is in contrast to published concepts and theories. Development of fibrosis appears to be uncoupled from acute inflammation.

Combined intra- and extra-articular grafting for revision ACL reconstruction: A multicentre study by the French Arthroscopy Society (SFA)

BACKGROUND

A careful analysis of the reasons for ACL reconstruction failure is essential to selection of the optimal surgical revision technique designed to ensure good rotational stability and to minimise the risk of re-rupture.

OBJECTIVE

To evaluate anterolateral ligament (ALL) stabilisation during revision ACL reconstruction.

HYPOTHESIS

ALL stabilisation during revision ACL reconstruction provides good rotational stability without increasing the risk of complications.

MATERIAL AND METHODS

This multicentre study included 349 patients, 151 retrospectively and 198 prospectively. There were 283 males and 66 females. Inclusion criteria were an indication for revision ACL reconstruction surgery with combined intra-articular reconstruction and ALL stabilisation after failed autograft ACL reconstruction, and intact PCL. Exclusion criteria were primary ACL reconstruction and concomitant peripheral medial and/or lateral lesions. Each patient underwent a clinical and radiographic evaluation before and after revision surgery. Before revision surgery, the mean IKDC score was 56.5±15.5 and 96% of patients were IKDC C or D.

RESULTS

Rates were 5.0% for early and 10.5% for late postoperative complications. Lachmann's test had a hard stop at last follow-up in 97% of patients. The pivot-shift test was positive in 1% of patients. The mean subjective IKDC score was 84.5±13.0 and 86.5% of patients were IKDC A or B. The proportions of patients with radiographic knee osteoarthritis at last follow-up was unchanged for the lateral tibio-femoral and patello-femoral compartments but increased by 9.7% to 21.2% for the medial tibio-femoral compartment. The re-rupture rate was 1.2% and the further surgical revision rate was 5.4%.

CONCLUSION

Anterior laxity at last follow-up was consistent with previous studies of revision ACL reconstruction. However, rotational stability and the re-rupture risk were improved. ALL stabilisation is among the techniques that deserve consideration as part of the therapeutic options for revision ACL reconstruction.

LEVEL OF EVIDENCE

IV, retrospective and prospective cohort study.

Midterm results of combined intra- and extra-articular ACL reconstruction compared to historical ACL reconstruction data. Multicenter study of the French Arthroscopy Society

INTRODUCTION

During anterior cruciate ligament (ACL) reconstruction procedures, anterolateral reconstruction (ALR) can also be performed to improve the knee's rotational stability. However, the effectiveness of this supplemental technique and its impact on the risk of retears and on the onset of secondary degenerative changesare controversial.

HYPOTHESIS

ALR improves control over the pivot shift, reduces the retear risk and delays the appearance of secondary degenerative lesions.

MATERIAL AND METHODS

Clinical examination, knee laxity measurements and X-ray evaluations were done in 478 patients with more than 3years' follow-up after combined ACL and ALR from 11 participating hospitals. The mean patient age at the time of surgery was 28years. Eighty-eight percent of the patients participated in pivot sports and 45% were competitive athletes. The findings of this study were compared to historical isolated ACL reconstruction data.

RESULTS

The average follow-up was 6.8years. No detectable pivot shift was found in 83% of patients, while 12.8% of patient had a smooth glide. The side-to-side difference in anteroposterior knee laxity with maximum manual force was less than 3mm in 66% of patients and less than 5mm in 95%. The retear rate was 5.4%, with half of these patients undergoing revision ACL surgery. Secondary meniscus damage requiring surgery occurred in 6.3% of patients; the radiological osteoarthritis rate was 17.5%.

DISCUSSION

When compared to historical ACL reconstruction data, combined intra- and extra-articular reconstruction does not increase the complication rate. At a mean follow-up of 6.8years, it provides better control over the pivot shift along with a low retear rate and low occurrence of secondary meniscus injuries.

LEVEL OF EVIDENCE

IV, multicenter study.

High-frequency burst vagal nerve simulation therapy in a natural primate model of genetic generalized epilepsy

PURPOSE

Since the approval of Vagal Nerve Stimulation (VNS) Therapy for medically refractory focal epilepsies in 1997, it has been also reported to be effective for a wide range of generalized seizures types and epilepsy syndromes. Instead of conventional VNS Therapy delivered at 20-30Hz signal frequencies, this study evaluates efficacy and tolerability of high-frequency burst VNS in a natural animal model for genetic generalized epilepsy (GGE), the epileptic baboon.

METHODS

Two female baboons (B1 P.h. Hamadryas and B2 P.h. Anubis x Cynocephalus) were selected because of frequently witnessed generalized tonic-clonic seizures (GTCS) for VNS implantation. High-frequency burst VNS Therapy was initiated after a 4-5 week baseline; different VNS settings (0.25, 2 or 2.5mA, 300Hz, 4 vs 7 pulses, 0.5-2.5s interburst interval, and intermittent stimulation for 1-2 vs for 24h per day) were tested over the subsequent 19 weeks, which included a 4-6 week wash-out period. GTCS frequencies were quantified for each setting, while seizure duration and postictal recovery times were compared to baseline. Scalp EEG studies were performed at almost every setting, including intermittent light stimulation (ILS) to evaluate photosensitivity. Pre-ILS ictal and interictal discharge rates, as well as ILS responses were compared between trials. The Novel Object test was used to assess potential treatment effects on behavior.

RESULTS

High-frequency burst VNS Therapy reduced GTCS frequencies at all treatment settings in both baboons, except when output currents were reduced (0.25mA) or intermittent stimulation was restricted (to 1-2h/day). Seizure duration and postictal recovery times were unchanged. Scalp EEG studies did not demonstrate treatment-related decrease of ictal or interictal epileptic discharges or photosensitivity, but continuous treatment for 120-180s during ILS appeared to reduce photoparoxysmal responses. High-frequency burst VNS Therapy was well-tolerated by both baboons, without cardiac or behavioral changes. Repetitive muscle contractions involving the neck and left shoulder girdle were observed intermittently, most commonly at 0.5 interburst intervals, but these were transient, resolving with a few cycles of stimulation and not noted in wakefulness.

CONCLUSIONS

This preclinical pilot study demonstrates efficacy and tolerability of high-frequency burst VNS Therapy in the baboon model of GGE. The muscle contractions may be due to aberrant propagation of the stimulus along the vagal nerve or to the ansa cervicalis, but can be reduced by minimal adjustment of current output or stimulus duration.

Abstract 77: Preclinical evaluation of HDP-101, an anti-BCMA antibody-drug conjugate

Background:

ATACs (antibody-targeted Amanitin conjugates) comprise a new class of antibody-drug conjugates using amanitin as toxic payload. Amanitin binds to the eukaryotic RNA pol II and thereby inhibits the cellular transcription process at very low concentrations. In the current study, in vitro and in vivo data of new ATACs targeting BCMA (B Cell Maturation Antigen, also known as CD269) are presented. BCMA is selectively expressed on malignant plasma cells like in multiple myeloma (MM) and hence considered an ideal target for Amanitin based ADCs.

Material and methods:

MM cell lines: NCI-H929, MM.1S Luc (stable luciferase transfected) and CCRF-CEM (BCMA negative).

Antibody: anti-BCMA Thiomab (Max Delbrück Centrum, Berlin; derivatization and production at Heidelberg Pharma).

Synthesis of HDP-101: Maleimide amanitin compounds were conjugated to substituted cysteine residues of the anti-BCMA Thiomab.

Cell proliferation assay: Quantitative determination of cytotoxicity was performed by CellTiter Glo 2.0 assay (Promega) or WST.1 assay (Roche).

Animal models: Subcutaneous and metastatic mouse xenograft tumor models with MM cell lines NCI-H929 and MM.1S Luc were performed in single-dose and multiple-dosing experiments. Tolerability was assessed in mice and nonhuman primates (NHP).

Results:

HDP-101 showed in vitro cytotoxicity on BCMA+ cell lines in picomolar range, whereas no cytotoxic activity on BCMA- cells was observed.

In mouse xenograft models, HDP-101 caused dose-dependent tumor regression and complete remission after a single i.v. dose of 2.0 mg/kg and 4.0 mg/kg in s.c. xenografts and after single i.v. doses from 0.1 mg/kg to 2.0 mg/kg in disseminating xenografts.

Safety profiling in Cynomolgus monkeys revealed a good tolerability and therapeutic index after sequentially applied doses of 0.3, 1.0, and multiple dose application of 4 x 3.0 mg/kg. Hematology and clinical chemistry parameters were unaffected except liver enzymes and LDH: A mild to moderate and transient increase was observed. The half-life of the ADC in serum was 7-9 days; the free toxin was detectable at levels close to the lower limit of quantification only (LLOQ = 1.2nM).

Conclusions:

Targeted cytotoxic drug delivery to BCMA positive MM cell lines was achieved by using HDP-101, an anti-BCMA-ATAC. The mode of action of the payload Amanitin led to an efficient anti-tumor potential in vitro and in vivo with good tolerability in NHP studies. Using ADCs in the therapy of multiple myeloma is a promising approach, especially by using a cytotoxic agent whose mode of action differs from other commonly used toxins, like ATACs. First-in-human trial is expected to start in 2018.

Citation Format: Torsten Hechler, Aniko Palfi, Christoph Müller, Christian Lutz, Andreas Pahl, Michael Kulke. Preclinical evaluation of HDP-101, an anti-BCMA antibody-drug conjugate [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 77. doi:10.1158/1538-7445.AM2017-77

Abstract B77: CYP3A5 mediates basal and acquired therapy resistance in different subtypes of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a very aggressive disease with poor prognosis. Treatment with gemcitabine, the FOLFIRINOX scheme or nab-paclitaxel offer only a modest increase in overall survival. For a number of other carcinomas, tumor subtypes have been uncovered that allow the use of targeted therapies. Although subtypes of PDAC were described, this malignancy is clinically still treated as a single disease. We established patient-derived models representing the full spectrum of previously identified quasi-mesenchymal (QM-PDA), classical and exocrine-like PDAC subtypes, and identified two markers—HNF1A and KRT81—that enable stratification of tumors into different subtypes by immunohistochemistry. Patients bearing tumors of these subtypes show significant differences in overall survival and their tumors differ in drug sensitivity, with the exocrine-like subtype being resistant to tyrosine kinase inhibitors and paclitaxel. The xenobiotic enzyme, cytochrome P450 3A5 (CYP3A5), metabolizes these compounds in tumors of the exocrine-like subtype, and pharmacological or short hairpin RNA (shRNA)-mediated CYP3A5 inhibition sensitizes tumor cells to these drugs. Additionally, retrospective analysis of a large patient cohort confirmed that CYP3A5 is predominantly found in those patient tumors classified as exocrine-like. Whereas the hepatocyte nuclear factor 4, alpha (HNF4A) controls basal expression of CYP3A5, drug-induced CYP3A5 upregulation is mediated by the nuclear receptor NR1I2. Interfering with these regulatory mechanisms may provide an alternative approach to suppress the CYP3A5 pathway. CYP3A5 also contributes to acquired drug resistance in QM-PDA and classical PDAC, and is highly expressed in several additional malignancies. These findings designate CYP3A5 as predictor of therapy response and as a tumor cell-autonomous detoxification mechanism that must be overcome to prevent drug resistance.

Citation Format: Elisa M. Noll, Christian Eisen, Albrecht Stenzinger, Elisa Espinet, Alexander Muckenhuber, Corinna Klein, Vanessa Vogel, Bernd Klaus, Wiebke Nadler, Christoph Rösli, Christian Lutz, Michael Kulke, Jan Engelhardt, Franziska Zickgraf, Octavio Espinosa, Matthias Schlesner, Xiaoqi Jiang, Annette Kopp-Schneider, Peter Neuhaus, Marcus Bahra, Bruno V. Sinn, Roland Eils, Nathalia A. Giese, Thilo Hackert, Oliver Strobel, Jens Werner, Markus W. Büchler, Wilko Weichert, Andreas Trumpp, Martin R. Sprick.{Authors}. CYP3A5 mediates basal and acquired therapy resistance in different subtypes of pancreatic ductal adenocarcinoma. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2016 May 12-15; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2016;76(24 Suppl):Abstract nr B77.

Anesthesia and analgesia methods for outpatient anterior cruciate ligament reconstruction

INTRODUCTION

More and more anterior cruciate ligament (ACL) reconstructions are being performed as outpatient surgery in France, because of economic considerations. Postoperative pain is the most common reason for delayed discharge that could require hospitalization, and the main reason for unanticipated hospital admission. The purpose of this study was to define the best anesthesia and analgesia methods for ACL reconstruction.

MATERIALS AND METHODS

This was a prospective, multicenter, comparative study performed between January 2014 and April 2015. Inclusion criteria were ACL reconstruction in patients above 15 years of age performed as an outpatient surgical procedure. The anesthesia techniques analyzed were general anesthesia, spinal anesthesia and quadruple nerve blockade. The analgesic methods studied were single-shot nerve blocks, continuous nerve blocks, peri-articular and intra-articular local infiltration analgesia (LIA), non-steroidal anti-inflammatory agents (NSAIDs) and intravenous corticosteroids. The main outcome criterion was pain on a visual analog scale (VAS). The secondary outcome criteria were delayed discharge of a patient who had undergone outpatient surgery, consumption of opioids and complications for the various anesthesia techniques and analgesia methods.

RESULTS

In all, 680 patients were included in this study, which was 63% of the ACL reconstruction procedures performed during this period. The study population was 69% male and 31% female, with an average age of 30 years. Twenty-three patients (3.4%) could not be discharged on the day of surgery. No correlation was found with the anesthesia technique used. NSAID treatment was protective relative to delayed discharge (P=0.009), while opioid consumption was a risk factor (P<0.01). There were no differences in the pain levels related to the type of anesthesia. Peri-articular LIA of the hamstring tendon harvest site was effective. Intra-articular LIA did not provide better analgesia. Continuous nerve block had complication rates above 13%.

DISCUSSION

All types of anesthesia were compatible with outpatient ACL reconstruction. No gold standard analgesia method can be defined based on this study's findings. However, we recommend multimodal analgesia associating peri-articular LIA or one-shot sensory saphenous nerve block, NSAIDs and corticosteroid treatment, and cryotherapy.

LEVEL OF EVIDENCE

II, prospective comparative non-randomized study.

Isometric Characteristics of the Anterolateral Ligament of the Knee: A Cadaveric Navigation Study

PURPOSE

To measure the variations in length during flexion and internal tibial rotation of the 3 different femoral insertions of the anterolateral ligament (ALL) while maintaining a fixed tibia insertion.

METHODS

Twelve fresh-frozen cadaver knees were analyzed using a navigation system. Maximal distance variations of the 3 different anatomic femoral insertions of the ALL were measured during knee flexion and internal tibial rotation at 20° (IR20°) and 90° (IR90°). The 3 different femoral attachments were, as published, at the center of the lateral epicondyle, distal and anterior from this position, and proximal and posterior. Each of these 3 femoral insertions was coupled to the same tibial insertion at the tibial margin, halfway between the tip of the fibular head and the prominence of the Gerdy tubercle.

RESULTS

During IR20°, variation in the distance between paired points is not different between the proximal-posterior, epicondyle, and distal-anterior femoral insertions. These variations were statistically different during IR90° for the 3 different femoral locations. In increasing degrees of flexion, there was a length decrease between paired points observed with the proximal-posterior position. A length increase was observed for both the epicondyle location and the distal-anterior location.

CONCLUSIONS

The ALL did not reveal an isometric behavior at any of the femoral insertion locations but had different length change patterns during knee flexion and internal tibial rotation at 90°. The proximal and posterior to epicondyle femoral position is the only position with a favorable isometry, as shown by being tight in extension and in internal rotation at 20° and then relaxed when the knee goes to flexion at 120° and during internal rotation at 90°.

CLINICAL RELEVANCE

Clinical relevance is significant with respect to optimizing the femoral position of an ALL reconstruction.

Ag2S atomic switch-based 'tug of war' for decision making

For a computing process such as making a decision, a software controlled chip of several transistors is necessary. Inspired by how a single cell amoeba decides its movements, the theoretical 'tug of war' computing model was proposed but not yet implemented in an analogue device suitable for integrated circuits. Based on this model, we now developed a new electronic element for decision making processes, which will have no need for prior programming. The devices are based on the growth and shrinkage of Ag filaments in α-Ag2+δS gap-type atomic switches. Here we present the adapted device design and the new materials. We demonstrate the basic 'tug of war' operation by IV-measurements and Scanning Electron Microscopy (SEM) observation. These devices could be the base for a CMOS-free new computer architecture.

Abstract LB-120: CYP3A5 mediates basal and acquired therapy resistance in different subtypes of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive disease with poor prognosis. Treatment with gemcitabine, the FOLFIRINOX scheme or nab-paclitaxel offer only a modest increase in overall survival. For a number of other carcinomas, tumor subtypes have been uncovered that allow the use of targeted therapies. Although subtypes of PDAC were described, this malignancy is clinically still treated as a single disease. We established patient-derived models representing the full spectrum of previously identified quasi-mesenchymal (QM-PDA), classical and exocrine-like PDAC subtypes, and identified two markers—HNF1A and KRT81—that enable stratification of tumors into different subtypes by immunohistochemistry. Patients bearing tumors of these subtypes show significant differences in overall survival and their tumors differ in drug sensitivity, with the exocrine-like subtype being resistant to tyrosine kinase inhibitors and paclitaxel. The xenobiotic enzyme, cytochrome P450 3A5 (CYP3A5), metabolizes these compounds in tumor cells of the exocrine-like subtype, and pharmacological or short hairpin RNA (shRNA)-mediated CYP3A5 inhibition sensitizes tumor cells to these drugs. Additionally, retrospective analysis of a large patient cohort confirmed that CYP3A5 is predominantly found in those patient tumors classified as exocrine-like (Noll, Eisen et al., Nature Medicine (2016) accepted). Whereas the hepatocyte nuclear factor 4, alpha (HNF4A) controls basal expression of CYP3A5, drug-induced CYP3A5 upregulation is mediated by the nuclear receptor NR1I2. Interfering with these regulatory mechanisms may provide an alternative approach to suppress the CYP3A5 mediated resistance pathway. CYP3A5 also contributes to acquired drug resistance in QM-PDA and classical PDAC in vitro and in vivo. Finally, CYP3A5 is highly expressed in several additional malignancies including hepatocellular and cervical carcinomas raising the possibility that the CYP3A5 resistance mechanism is operational in a variety of human cancers. These findings designate CYP3A5 as predictor of therapy response and as a tumor cell-autonomous detoxification mechanism that must be overcome to prevent drug resistance.

Citation Format: Elisa M. Noll, Christian Eisen, Albrecht Stenzinger, Elisa Espinet, Alexander Muckenhuber, Corinna Klein, Vanessa Vogel, Bernd Klaus, Wiebke Nadler, Christoph Rösli, Christian Lutz, Michael Kulke, Jan Engelhardt, Franziska Zickgraf, Octavio Espinosa, Matthias Schlesner, Xiaoqi Jiang, Annette Kopp-Schneider, Peter Neuhaus, Marcus Bahra, Bruno Sinn, Roland Eils, Nathalia Giese, Thilo Hackert, Oliver Strobel, Jens Werner, Markus W. Büchler, Wilko Weichert, Andreas Trumpp, Martin R. Sprick. CYP3A5 mediates basal and acquired therapy resistance in different subtypes of pancreatic ductal adenocarcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-120.

The Involvement of the Anterolateral Ligament in Rotational Control of the Knee

BACKGROUND

Rotational control of the knee is crucial for knee stability. The anterolateral ligament (ALL) has been identified as a potentially important structure involved in rotational control of the knee.

PURPOSE/HYPOTHESIS

The purpose of this study was to determine, utilizing a navigation system, the involvement of the anterior cruciate ligament (ACL), the iliotibial band (ITB), and the ALL in tibial internal rotational control of the knee. The hypothesis was that the ALL would be involved in rotational control of the knee at varying degrees of knee flexion.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twelve fresh-frozen cadaveric knees were tested in internal rotation at 20° and 90° of flexion and then subsequently tested using a simulated pivot-shift test consisting of coupled axial rotation at 30° of flexion. Serial sectioning of the ACL, ALL, and ITB was performed. On the contralateral knee, sectioning was performed in the reverse order. Measurements were collected using a surgical navigation system before and after each sectioning.

RESULTS

After ACL sectioning, an incision of the ALL induced a significant increase in internal rotation (+19.2% [P = .0002] at 20°; +21.8% [P = .0029] at 90°) and in coupled axial rotation (+43.0%; P = .0035) compared with the intact knee as well as a significant increase in internal rotation at 90° (+13.4%; P = .009) and in coupled axial rotation (+30.8%; P = .0124) compared with the ACL-deficient knee. After ITB sectioning, an additional ALL section caused a significant increase in internal rotation (+39.0% [P = .002] at 20°; +63.0% [P = .0147] at 90°) and in coupled axial rotation (+59.7%; P = .0003) compared with the intact knee as well as a significant increase in internal rotation at 90° (+14.8%; P = .0067) in comparison to the ITB-deficient knee.

CONCLUSION

The ALL is involved in rotational control of the knee at varying degrees of knee flexion and during a simulated pivot shift. Concomitant to an ACL or ITB transection, sectioning the ALL further increased rotational laxity.

CLINICAL RELEVANCE

This laboratory study demonstrated that the ALL provides rotational control of the knee in combination with the ACL and/or ITB.

Femoral Origin of the Anterolateral Ligament: An Anatomic Analysis

PURPOSE

To determine the location and variability of the anterolateral ligament (ALL) femoral origin.

METHODS

The ALL was dissected and examined in 52 embalmed specimens, and the femoral origin was isolated. The presence of a bony or soft-tissue attachment, the relation to the lateral collateral ligament, the average diameter of the proximal origin, and the specific location of the origin relative to the lateral femoral epicondyle were recorded.

RESULTS

The ALL was present in all 52 specimens, with a mean diameter of 11.85 mm, and was consistently attached to bone in all specimens. The ALL consistently overlapped the lateral collateral ligament near its attachment, with the location of the origin directly on the lateral epicondyle in 12 specimens (23%), with a shared lateral femoral condyle and with the origin slightly posterior and proximal to the lateral epicondyle in 30 specimens (58%), and with the origin completely posterior and proximal to the lateral epicondyle in 10 specimens (19%).

CONCLUSIONS

The ALL showed a consistent bony origin overlapping the lateral collateral ligament in all specimens, with some variability in the femoral attachment, ranging from directly on the lateral epicondyle to posterior to the lateral epicondyle.

CLINICAL RELEVANCE

The identification and description of the femoral origin of the ALL are crucial in understanding its role in the stability of the knee, as well as determining the appropriate position for the femoral origin placement in ALL reconstruction.

Combined Anterior and Anterolateral Stabilization of the Knee With the Iliotibial Band

Interest and knowledge on the anatomy, function, and biomechanical properties of the anterolateral ligament has led to the recognition of the importance of this structure in rotational control of the knee. This article describes a technique that allows for a combined anterior cruciate ligament (ACL) and anterolateral reconstruction, using an Iliotibial band (ITB) autograft. The graft is detached from the vastus lateralis from proximal to distal, at the center portion from ITB, preserving its distal insertion on the Gerdy tubercle. Its width is 1 cm for the distal part, used for the anterolateral ligament reconstruction, and 3 cm for the proximal part. An outside-in femoral tunnel is drilled respecting both the preferred favorable isometric femoral insertion site and the femoral ACL footprint. An ACL reconstruction combined with a lateral tenodesis with a continuous ITB graft respects the anatomical and isometric rules providing superior internal rotational control of the knee in comparison with a stand-alone ACL reconstruction.

Meniscectomy versus meniscal repair: 10 years radiological and clinical results in vertical lesions in stable knee

INTRODUCTION

Surgical management of meniscal lesion consists of either a meniscectomy or meniscal repair. Although repair offers immediate recovery after surgery, it is also associated with higher rates of revision. A meniscectomy, on the other hand is known to be associated with an early onset of osteoarthritis. The present study compared clinical and radiological results at 10 years between meniscectomy and meniscal repair in isolated vertical lesion in an otherwise stable knee. The hypothesis was that repair shows functional and radiological benefit over meniscectomy.

PATIENTS AND METHOD

A multi-centric retrospective comparative study of 32 patients (24 male, 8 female). Mean follow-up was 10.6 years (range, 10-13 years). There were 10 meniscal repairs (group R) and 22 meniscectomies (group M), in 17 right and 15 left knees. Mean age at surgery was 33.45±12.3 years (range, 9-47 years). There were 28 medial and 4 lateral meniscal lesions; 26 were in the red-red zone and 6 in red-white zone.

RESULTS

Functional score: KOOS score was significantly higher in group R than M on almost all parameters: 98±4.69 versus 77.38±21.97 for symptoms (P=0.0043), 96.89±7.20 versus 78.57±18.9 for pain (P=0.0052), 99.89±0.33 versus 80.88±19.6 for daily life activities (P=0.0002), 96.11±9.83 versus 54.05±32.85 for sport and leisure (P=0.0005), but 91±16.87 versus 68.15±37.7 for quality of life (P=0.1048). Radiology score: in group R, 7 patients had no features of osteoarthritis, and 2 had grade 1 osteoarthritis. In group M, 5 patients had grade 1 osteoarthritis, 10 grade 2, 3 grade 3 and 3 grade 4. Mean quantitative score was 0 (mean, 0.22±0.44) in-group R and 2 (mean, 2.19±0.98) in group M (P<0.0001).

DISCUSSION

At more than 10year's follow-up, functional scores were significantly better with meniscal repair than meniscectomy on all parameters of the KOOS scale except quality of life. Functional and radiological scores correlated closely. These results show that meniscal repair for vertical lesions in stable knees protects against osteoarthritis and is therefore strongly recommended.

LEVEL OF EVIDENCE

IV; retrospective study.

Meniscal survival rate after anterior cruciate ligament reconstruction

BACKGROUND

Meniscal suture provides well-documented benefits. Integrity of the cruciate ligaments of the knee is a prerequisite for meniscal healing. Nevertheless, reconstruction of the anterior cruciate ligament (ACL) does not consistently prevent recurrent tearing of a sutured meniscus. We evaluated meniscal survival rates, 5 and 10 years after meniscal suture concomitant with an ACL reconstruction. We compared the outcomes of these repaired menisci to those in which no menisci tears were detected during ACL reconstruction.

METHODS

In this multi-centric retrospective study, we included two groups. One group consists of patients who underwent a meniscal repair. This group was further divided into two subgroups based on whether follow-up was 5 years (n=76) or 10 years (n=39). The control group included 120 patients with normal menisci observed during surgery. We studied meniscal survival rates in each group, and we analyzed risk factors associated with the recurrence of meniscal lesions.

RESULTS

The 5-year meniscal survival rate was significantly higher in the control group than in the meniscal-repair group (95% vs. 80%, respectively; P=0.0029). The controls group also had a higher meniscal survival rate after 10 years, although the difference was not statistically significant (88% vs. 77%, P=0.07). A difference in knee laxity greater than 4mm was associated with a 5-fold increase in the risk of recurrent meniscal tears (P=0.0057). After 5 years, the risk of recurrence was higher for the medial than for the lateral meniscus, whereas after 10 years the difference was no longer statistically significant.

DISCUSSION

Although insufficient healing after meniscal suturing contributes to the risk of further meniscal tears, new lesions can develop in menisci that were undamaged at the time of ACL reconstruction. The risk of a new meniscal lesion is strongly associated with inadequate control of antero-posterior and rotational laxity. Some apparently "new menisci lesions" seems to have been missed during ACL reconstruction.

LEVEL OF EVIDENCE

IV, retrospective study.

Abstract A69: A novel mechanism mediates drug resistance in the exocrine-like pancreatic ductal adenocarcinoma (PDAC) subtype

PDAC is a highly aggressive disease with dismal prognosis [1, 2]. Despite extensive research and the discovery of several drug candidates, little progress has been reported since the approval of gemcitabine and erlotinib [1]. Moreover, recent trials with targeted therapies have shown only limited or no benefit [1, 2]. For a number of other carcinomas, tumor subclasses have been uncovered that allow the use of targeted therapies. The mutational landscape of PDAC is complex and heterogeneous, raising the question whether subclasses also exist in PDAC [3]. Collisson et al. described three PDAC subtypes that were identified based on their gene-expression profiles: The classical, the quasi-mesenchymal and the exocrine-like subtype [4]. However, not all subtypes could be identified in the previously available model systems. We have established a novel patient-derived model system that allows the analysis of these three human PDAC subtypes in vitro and in vivo. Hence, we provide a systematic workflow to propagate human PDAC in orthotopic xenografts and to derive tumor-initiating primary cell lines of all three PDAC subtypes. HNF-1 and Keratin 81 were identified as markers for subtype stratification by immunohistochemistry. Application of this two-marker set on a 258 large patient cohort confirmed a predominantly non-overlapping staining and revealed a significant difference in overall survival across the three subtypes. Furthermore, a drug screen uncovered subtype-specific drug sensitivities towards a number of drugs, including gemcitabine and dasatinib. Notably, the exocrine-like subtype was resistant towards all compounds tested. Thus, we aimed to identify the underlying cause of the observed drug resistance. Molecular analysis including gene set enrichment analysis (GSEA) allowed us to identify a putative novel mechanism of drug resistance. Analysis by qRT-PCR and Western blot demonstrated the enhanced expression of several genes mediating this mechanism particularly in the exocrine-like subtype in vitro and in vivo. These findings led to the identification of a novel protein target central to this mechanism. Additionally, retrospective immunohistochemical analysis of a large patient cohort confirmed that this target is predominantly found in those patient tumors classified as exocrine-like. Hence, we hypothesized that the observed strong activation of this mechanism in the exocrine-like PDAC subtype could be responsible for the drug resistance observed in this subclass. In line with this, functional inhibition of this mechanism resulted in increased drug sensitivity in the exocrine-like subtype. Hence, our findings may ultimately advance personalized treatment by applying novel marker-based patient selection strategies in combination with tailored drug use, a strategy which will be presented in more detail at the conference.

[1] Hidalgo, M. Pancreatic cancer. The New England journal of medicine. 362, 1605-1617, doi:10.1056/NEJMra0901557 (2010).

[2] Vincent, A., Herman, J., Schulick, R., Hruban, R. H. & Goggins, M. Pancreatic cancer. Lancet. 378, 607-620, doi:10.1016/S0140-6736(10)62307-0 (2011).

[3] Jones, S. et al. Core signalling pathways in human pancreatic cancers revealed by global genomic analyses. Science. 321, 1801-1806, doi:10.1126/science.1164368 (2008).

[4] Collisson, E. A. et al. Subtypes of pancreatic ductal adenocarcinoma and their differing responses to therapy. Nature medicine. 17, 500-503, doi:10.1038/nm.2344 (2011).

Citation Format: Elisa M. Noll, Christian Eisen, Elisa Espinet, Vanessa Vogel, Corinna Klein, Albrecht Stenzinger, Franziska Zickgraf, Peter Neuhaus, Marcus Bahra, Bruno V. Sinn, Christian Lutz, Michael Kulke, Andreas Pahl, Nathalia A. Giese, Oliver Strobel, Jens Werner, Wilko Weichert, Andreas Trumpp, Martin R. Sprick. A novel mechanism mediates drug resistance in the exocrine-like pancreatic ductal adenocarcinoma (PDAC) subtype. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Innovations in Research and Treatment; May 18-21, 2014; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2015;75(13 Suppl):Abstract nr A69.