Full aperture backscatter diagnostics for characterization of laser plasma instabilities at the extreme light infrastructure (ELI) beamlines

We report on the commissioning of a full aperture backscatter diagnostics station for the kilojoule, nanosecond high repetition rate L4n laser operating at a wavelength of 527 nm at the Extreme Light Infrastructure (ELI) - Beamlines, Dolni Brezany, Czech Republic. Light scattered back from laser-plasma interaction into the cone of the final focusing lens is captured and split into different channels to measure the signatures of laser plasma instabilities from stimulated Brillouin scattering, stimulated Raman scattering, and two plasmon decay with respect to back scattered energy, its spectrum, and its temporal profile. The performance was confirmed in a commissioning experiment with more than 800 shots at laser intensities ranging from 0.5 × 1013 to 1.1 × 1015 W cm-2. These diagnostics are permanently installed at ELI Beamlines, and can be used to understand the details of laser-plasma interactions in experiments with kJ and 527 nm light. The large number of shots that can be collected in an experimental campaign will allow us to study the details of the laser-plasma interaction with a high level of confidence.

Robotic Retroperitoneal Versus Transperitoneal Partial Nephrectomy: Outcomes and Learning Curve

BACKGROUND/AIM

The robotic retroperitoneal approach for renal mass surgery was introduced in 2018 at the Department of Urology in the clinic of Leverkusen, Germany. Clinical criteria for the choice of the access site (trans- vs. retroperitoneal) are not clearly defined. The aim of this study was to explore the learning curve and the impact of the access site on clinical outcome, in order to elucidate which preoperative clinical criteria should be taken into account when choosing the renal approach site.

PATIENTS AND METHODS

This retrospective study included 107 patients who underwent robotic tumor surgery between June 2018 and March 2022 at the Department of Urology in the Clinic of Leverkusen, Germany. Data from 86 patients with transperitoneal robotic surgery of the kidney and 21 patients with retroperitoneal access were available for analysis. We evaluated the data of patients in a trans- and a retroperitoneal access group. The preoperative clinical data included anthropomorphic data, the Body Mass Index (BMI) as well as the Preoperative Aspects and Dimensions Used for Anatomical Classification of Renal Masses (PADUA) - score. Intraoperative and postoperative data such as blood loss, clamping time, renal function and the learning curve of the surgeons was used to evaluate the outcomes of the two groups.

RESULTS

Operation time in the retroperitoneal group was significantly shorter (p=0.015). Operation-specific variables showed no significant difference between the two groups. PADUA score and hilar clamping time showed no difference (p=0.345 and p=0.130, respectively). The learning curve in the retroperitoneal access group unveiled a noticeable difference in the experience and mastery of the involved surgeons.

CONCLUSION

Mastery of the retroperitoneal approach is readily possible for surgeons with previous experience in robotic renal surgery without compromising the operative morbidity. The PADUA-score seems most suitable as a preoperative clinical criterion for choosing the renal approach site.

Abstract 5100: Combination of κλ bispecific antibodies targeting innate (CEAxCD47, NILK-2401) and adaptive immunity (CEAxCD3, NILK-2301 and CEAxCD28, NILK-3301) for next generation immunotherapy of CEA-expressing cancers

Background: The CEAxCD3 bispecific antibody (bsAb) NILK-2301 couples CEA (CEACAM5) on cancer cells and CD3 on T-cells inducing T-cell activation (signal 1) and tumor cell killing (TDCC). T-cell activation can be boosted by CEA-targeted CD28-costimulation (NILK-3301; signal 2). NILK-2401, carrying a fully effective IgG1 Fc, induces antibody-dependent phagocytosis (ADCP) and antibody-dependent cytotoxicity (ADCC) of tumor cells by co-targeting CEA and the innate immune checkpoint CD47 (“don’t eat me” signal). We present here next generation immunotherapy to overcome limited single class activity in CEA-expressing solid cancers.

Methods: BsAbs were generated using LCB’s fully human κλ body platform. TDCC, ADCP, and ADCC with human PBMC or monocyte-derived macrophages were assessed using CEA+ colorectal (n=3), lung (n=2), and gastric (n=2) cancer lines. Combination activity of NILK-2401 + NILK-2301 (± NILK-3301) was assessed by flow cytometry. In vivo activity was tested in xenograft NOG or NSG/human PMBC-, HIS-, and hSIRPα/hCD47/hCD3/hCD28 transgenic mice. Safety data include binding to other CEACAMs, cytokine release in whole blood, erythrophagocytosis, platelet activation, exclusion of superagonism (NILK-3301), as well as PK- and tolerability in cynomolgus monkeys and Tg32-mice.

Results: NILK-2301 induced dose-dependent killing of all tested cell lines, which was also visualized by live cell imaging. Combination of NILK-2301 (1 nM) + NILK-3301 vs. NILK-2301 alone (10 nM) increased TDCC (3-8-fold), T-cell activation (CD25, CD69, HLA-DR), cytokine secretion (interferon-γ, granzyme B, perforin), and CD4+/CD8+ T-cell proliferation. NILK-2401 blocked CD47-SIRPα interaction and induced ADCP/ADCC-mediated elimination of all cell lines. NILK-2301 + NILK-2401 treatment increased maximum activity (Emax) and reduced necessary dose of the T-cell bsAb to reach Emax. E.g., Emax of 30% killing (NILK-2301 alone) was increased in combination with NILK-2401 at 0.1/1/10 µg/mL to 40%, 80%, and 80%. In vivo, NILK-2301 (10 mg/kg IV, BIW) decreased tumor progression. NILK-2301/-3301 combination induced tumor regression in 8/8 mice. NILK-2401 delayed tumor growth vs. mean of control in 100% (15/15) of mice and prevented establishment of detectable tumors (>50mm3) in 53% (8/15). Results of double and quadruple transgenic mice, including triple bsAb combinations, will be presented at the meeting. No relevant safety signals were detected.

Conclusions: NILK-2301 and NILK-2401 are active as single agents. Addition of NILK-2401 or NILK-3301 to NILK-2301 significantly increases activity, already at 10 -100x lower CEAxCD3 doses. GMP drug substance has been produced for NILK-2301 and NILK-2401. Generation of the clonal cell line for NILK-3301 clinical material production is ongoing.

Citation Format: Anja Seckinger, Lise Nouveau, Sara Majocchi, Valéry Moine, Vanessa Buatois, Bruno Daubeuf, Franck Gueneau, Ulla Ravn, Krzysztof Masternak, Yves Poitevin, Emeline Rousset, Giovanni Magistrelli, Pauline Malinge, Limin Shang, Nicolas Fischer, Klaus Strein, Walter Ferlin, Dirk Hose. Combination of κλ bispecific antibodies targeting innate (CEAxCD47, NILK-2401) and adaptive immunity (CEAxCD3, NILK-2301 and CEAxCD28, NILK-3301) for next generation immunotherapy of CEA-expressing cancers. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5100.

Abstract 2951: NI-2901, an affinity-optimized CD47xPD-L1 bispecific antibody for dual immune checkpoint blockade

To enhance efficacy of anti-PD-1/PD-L1 antibodies, many combinations with various therapeutic agents are being investigated. Blocking the CD47/SIRPα myeloid checkpoint with monoclonal antibodies (mAbs) or decoy receptors is emerging as an effective approach to mobilize dendritic cells and macrophages to support T-cell mediated antitumor responses. The benefit of combining CD47/SIRPα and PD-1/PD-L1 blockade to improve tumor control has been convincingly demonstrated in preclinical models and is now being explored in patients. However, CD47 mAbs are hindered by ubiquitous CD47 expression, leading to pharmacokinetic (PK) and safety issues.NI-2901, an IgG4 CD47xPD-L1 bispecific antibody (bsAb), was generated using the κλ-body platform. In vitro assays were used to characterize its binding profile and checkpoint inhibition as well as its capacity to enhance T-cell activation and macrophage-mediated phagocytosis of tumor cells. PD-L1-independent CD47 antitumor activity was assessed in vivo in a PD-L1-negative xenograft model and compared to the anti-CD47 magrolimab analog. PK and tolerability of NI-2901 were evaluated in non-human primates (NHP), allowing for translational modeling to predict PK and dosing regimens in humans. Consistent with its intermediate affinity to CD47, NI-2901 shows lower binding to RBC as compared to magrolimab analog and is still able to induce CD47/SIRPα blockade on PD-L1-negative tumor cells, that is significantly enhanced once PD-L1 is expressed. As a result, the bsAb is able to enhance the phagocytosis of PD-L1-negative and -positive tumor cell lines induced by mAbs targeting tumor-associated antigens (e.g. rituximab, trastuzumab and anti-CD19) and demonstrates in vivo activity in the Raji B-cell lymphoma xenograft model. Given its high affinity for PD-L1, NI-2901 triggers an effective blockade of the PD-1/PD-L1 interaction, inducing T-cell activation in vitro to a degree similar to anti-PD-L1 benchmark antibodies atezolizumab and avelumab. In immunocompetent huCD47/huSIRPα-transgenic mice engrafted with MC38 cells engineered to express human PD-L1 and CD47, NI-2901 displayed significant anti-tumor activity. In a NHP study, NI-2901 was well-tolerated after four weekly injections at 30mg/kg, showing no signs of hemotoxicity. In contrast, the magrolimab analog induced a significant drop in RBC already after a single injection at 10mg/kg. PK modeling and simulations in humans suggest a more favorable dosing regimen as compared to CD47 targeted approaches. In conclusion, NI-2901, a dual immune checkpoint inhibitor, triggered effective T-cell activation and enhanced phagocytosis of tumor cells. Also, NI-2901 demonstrated significant antitumor activity in vivo and is therefore expected to show improved clinical efficacy over PD-1/PD-L1 blockade alone. The bsAb was well-tolerated in NHP without inducing RBC or platelet depletion.

Citation Format: Xavier Chauchet, Sebastien Calloud, Pauline LLoveras, Nicolas Bosson, Margaux Legrand, Laurence Chatel, Laura Cons, Adeline Lesnier, Pauline Malinge, Guillemette Pontini, Christophe Guillamo, Dmitry Shchelokov, Oleg Demin, Ulla Ravn, Valéry Moine, Bruno Daubeuf, Giovanni Magistrelli, Yves Poitevin, Susana Salgado-Pires, Limin Shang, Nicolas Fischer, Walter Ferlin, Krzysztof Masternak. NI-2901, an affinity-optimized CD47xPD-L1 bispecific antibody for dual immune checkpoint blockade [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2951.

Abstract 2973: NI-3201,a PD-L1xCD28 bispecific antibody for immune checkpoint-dependent CD28 co-stimulation

CD28 agonism on T cells delivers a critical second signal alongside TCR ligation for complete T cell activation. In the tumor microenvironment (TME), signal 2 can be provided by bispecific antibodies (bsAbs) targeting CD28 and a tumor associated antigen (TAA), enabling CD28 clustering on T cells in a TAA-dependent manner. The inhibitory PD-L1/PD-1 axis is described to repress T cell activation by directly inhibiting CD28 driven costimulation, affecting mostly activated and/or exhausted T cells. Preclinical studies have shown the benefit of combining blocking anti-PD-1/-L1 antibodies and costimulatory CD28 bsAbs for the treatment of solid tumors. We reasoned that the effect of such a combination could be integrated into a single molecule, by associating a blocking anti-PD-L1 antibody arm with an agonist anti-CD28 antibody arm. To this end, a PD-L1xCD28 bsAb (NI-3201) was generated on the κλ body platform to block the PD-L1/PD-1 immune checkpoint, hence release the brake on CD28 signaling and provide signal 2 when co-ligating PD-L1+ tumor and immune cells (e.g., antigen-presenting cells). The capacity of NI-3201 to provide signal 2 to T cells following co-engagement of PD-L1 on tumor or immune cells was assessed in a variety of assays and models. Using a sensitive reporter cell bioassay, NI-3201 was shown to efficiently block the PD-L1/PD-1 axis. The pharmacological activity of NI-3201 was then assessed through in vitro assays of cancer cell lines co-cultured with human peripheral blood mononuclear cells (PBMCs). NI-3201 synergized with CD3 bsAbs to enhance activation and proliferation of both CD4 and CD8 T cells, ultimately leading to strengthened T cell-dependent cellular cytotoxicity (TDCC) against PD-L1-positive cancer cell lines. In immunocompetent huCD28-transgenic mice engrafted with huPD-L1-expressing murine colon adenocarcinoma MC38 cells, NI-3201 displayed superior single-agent activity as compared to the anti-PD-L1 antibody Atezolizumab, with tumor regression being observed in all treated mice. At study termination, most of the NI-3201-treated mice rejected MC38-huPD-L1 tumors. All surviving mice rechallenged with wild type MC38 cells rejected the tumors, thus demonstrating a durable anti-tumor immunological memory response induced by NI-3201. Finally, as the anti-PD-L1 arm of NI-3201 is cross-reactive to mouse PD-L1, it was noteworthy that NI-3201-treated huCD28-transgenic mice displayed no clinical signs of toxicity. NI-3201 has demonstrated potent activity in a plethora of assays and single agent anti-tumor in vivo activity superior to a clinically approved PD-L1 benchmark. The mechanism of action of NI-3201 and the data presented herein support the use of this molecule as a universal combination partner for CD3-bispecifics. Pre-clinical development of NI-3201 is ongoing, with pharmacokinetic and tolerability studies in non-human primates planned for early 2023.

Citation Format: Sara Majocchi, Pauline Lloveras, Coline Burnet-Merlin, Lise Nouveau, Pauline Malinge, Valery Moine, Giovanni Magistrelli, Limin Shang, Nicolas Fischer, Krzysztof Masternak, Walter Ferlin. NI-3201,a PD-L1xCD28 bispecific antibody for immune checkpoint-dependent CD28 co-stimulation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2973.

Biomechanical comparisons of three minimally invasive Achilles tendon percutaneous repair suture techniques

BACKGROUND

While no gold standard exists for the management of Achilles tendon ruptures, surgical repair is common in healthy and active patients. Minimally invasive repair methods have become increasingly popular, while biomechanical equivalency hasn't been proven yet.

METHODS

A mid-substance Achilles tendon rupture was created 6 cm proximal to the calcaneal insertion in 27 fresh-frozen cadaveric ankles. Specimens were randomly allocated to 1 of 3 repair techniques: Huttunen et al. (2014) (1) PARS Achilles Jig System, Nyyssönen et al. (2008) (2) Achilles Midsubstance SpeedBridge™, Schipper and Cohen (2017) (3) Dresdner Instrument and subsequently subjected to cyclic loading with 250 cycles each at 1 Hz with 4 different loading ranges (20-100 N, 20-200 N, 20-300 N, and 20-400 N).

FINDINGS

After 250 cycles no significant differences in elongation were observed between PARS and Dresdner Instrument(p = 1.0). Furthermore, SpeedBridge™ repairs elongated less than either Dresdner Instrument (p = 0.0006) or PARS (p = 0.102). Main elongation (85%) occurred within the first 10 cycles with a comparable elongation in between 10 and 100 and 100-250 cycles. While all repairs withstood the first 250 cycles of cyclic loading from 20 to 100 N, only the PARS (468 ± 175) and Midsubstance SpeedBridge™ (538 ± 208) survived more cycles. Within all 3 groups suture cut out was seen to be the most common failure mechanism.

INTERPRETATION

Within all groups early repair elongation was seen. While this was least obvious within the SpeedBridge™ technique, ultimate strengths of repairs (cycles to failure) were comparable across PARS and SpeedBridge™ with a decline in the Dresdner Instrument group.

Neurodegeneration and neuroinflammation are linked, but independent of alpha‐synuclein inclusions, in a seeding/spreading mouse model of Parkinson's disease

A key pathological process in Parkinson's disease (PD) is the transneuronal spreading of α‐synuclein. Alpha‐synuclein (α‐syn) is a presynaptic protein that, in PD, forms pathological inclusions. Other hallmarks of PD include neurodegeneration and microgliosis in susceptible brain regions. Whether it is primarily transneuronal spreading of α‐syn particles, inclusion formation, or other mechanisms, such as inflammation, that cause neurodegeneration in PD is unclear. We used a model of spreading of α‐syn induced by striatal injection of α‐syn preformed fibrils into the mouse striatum to address this question. We performed quantitative analysis for α‐syn inclusions, neurodegeneration, and microgliosis in different brain regions, and generated gene expression profiles of the ventral midbrain, at two different timepoints after disease induction. We observed significant neurodegeneration and microgliosis in brain regions not only with, but also without α‐syn inclusions. We also observed prominent microgliosis in injured brain regions that did not correlate with neurodegeneration nor with inclusion load. Using longitudinal gene expression profiling, we observed early gene expression changes, linked to neuroinflammation, that preceded neurodegeneration, indicating an active role of microglia in this process. Altered gene pathways overlapped with those typical of PD. Our observations indicate that α‐syn inclusion formation is not the major driver in the early phases of PD‐like neurodegeneration, but that microglia, activated by diffusible, oligomeric α‐syn, may play a key role in this process. Our findings uncover new features of α‐syn induced pathologies, in particular microgliosis, and point to the necessity for a broader view of the process of α‐syn spreading.

[Update on collaborative autopsy-based research in German pathology, neuropathology, and forensic medicine]

BACKGROUND

Autopsies are a valuable tool for understanding disease, including COVID-19.

MATERIALS AND METHODS

The German Registry of COVID-19 Autopsies (DeRegCOVID), established in April 2020, serves as the electronic backbone of the National Autopsy Network (NATON), launched in early 2022 following DEFEAT PANDEMIcs.

RESULTS

The NATON consortium's interconnected, collaborative autopsy research is enabled by an unprecedented collaboration of 138 individuals at more than 35 German university and non-university autopsy centers through which pathology, neuropathology, and forensic medicine autopsy data including data on biomaterials are collected in DeRegCOVID and tissue-based research and methods development are conducted. More than 145 publications have now emerged from participating autopsy centers, highlighting various basic science and clinical aspects of COVID-19, such as thromboembolic events, organ tropism, SARS-CoV‑2 detection methods, and infectivity of SARS-CoV-2 at autopsy.

CONCLUSIONS

Participating centers have demonstrated the high value of autopsy and autopsy-derived data and biomaterials to modern medicine. The planned long-term continuation and further development of the registry and network, as well as the open and participatory design, will allow the involvement of all interested partners.

Predictors for Outcome and Complications Related to Urinary Diversion

BACKGROUND/AIM

Predictors for complications such as insufficiency of intestinal anastomosis in urinary diversion and other risk factors are not well defined. We aimed to elucidate predictive factors for complications in urinary diversions based on preoperative comorbidities and major complications. A special focus was set on anastomosis insufficiency as a major complication.

PATIENTS AND METHODS

Preoperative comorbidities, postoperative complications, duration of hospital stay, and follow-up were analyzed in 317 patients with urinary diversion. The impact of preoperative comorbidities on diversion types was described and quantified as defined by the age-adjusted Charlson Comorbidity Index.

RESULTS

Overall, 14.8% of patients showed anastomosis-related complications, most within the ileal conduit group (15.9% in the cohort). Severe complications (Clavien-Dindo Classification Score >IIIa) were found in smokers (p=0.046), and in patients with vascular diseases (p=0.007), a high American Society of Anaesthesiologists (ASA)-score (p=0.047), a R1- (p=0.009), as well as a pN1 (p=0.007) status.

CONCLUSION

Several independent predictors for several postoperative complications in urinary diversions were identified, which were independent of the diversion method.

265 CD47xPD-L1 bispecific antibodies for cancer therapy

Background

PD-1/PD-L1 blockade can significantly improve survival across many types of cancer, but only in a minority of patients. To broaden its therapeutic efficacy, several combination partners are now being evaluated together with PD-1/PD-L1 blockade. Agents blocking CD47/SIRPα innate immune checkpoint are one such example, and co-targeting PD-1/PD-L1 and CD47 with monoclonal antibody (mAb) combinations showed increased antitumor responses in preclinical studies. However, CD47 mAbs are hindered by ubiquitous CD47 expression leading to rapid target-mediated clearance and safety concerns. Consequently, dual-targeting CD47xPD-L1 bispecific antibodies (bsAbs) enabling preferential inhibition of CD47 on PD-L1-positive cells are being tested as an alternative approach. We compare here two distinct bsAbs, based on a common PD-L1 antibody arm, with differing FcgR-enabling effector functions and CD47-binding arm affinities.

Methods

An array of fully human bsAbs associating a high affinity PD-L1 arm to CD47 arms with varying affinities were generated using the κλ-body platform.1 CD47xPD-L1 bsAbs of human IgG1 isotype (CD47 low affinities) or IgG4 isotype (CD47 high affinities) were screened in various binding assays (including to red blood cells (RBC)) and in receptor-blocking assays, and then tested for their Fc-mediated killing and T-cell activation activity (SEA-stimulated PBMC assay). Selected molecules were evaluated in vivo.

Results

Both bsAb approaches demonstrated strong blockade of PD-1/PD-L1 interaction and significantly enhanced T-cell activation in vitro. CD47lowxPD-L1 IgG1 bsAbs did not bind to RBC and showed PD-L1-guided inhibition of CD47. ADCP and ADCC experiments with a panel of tumor cell lines expressing various target levels showed superior killing activity with CD47lowxPD-L1 IgG1 bsAbs as compared to the anti-PD-L1 IgG1 mAb, avelumab. On the other hand, CD47highxPD-L1 IgG4 bsAbs showed residual RBC binding and PD-L1-independent blocking of CD47/SIRPα. These CD47high IgG4 bsAbs were able to enhance the anti-tumor activity of anti-tumor-associated antigen (TAA) mAbs in vitro (phagocytosis), and in vivo (Raji lymphoma xenograft model). In addition, anti-tumor activity of mouse CD47xPD-L1 bsAbs in a syngeneic MC38 colon carcinoma model was demonstrated.

Conclusions

With the objective of finding the optimal CD47xPD-L1 bsAb design, two approaches targeting CD47 and PD-L1 inhibition were tested. Both the CD47lowxPD-L1 IgG1 bsAbs and CD47highxPD-L1 IgG4 bsAbs were able to mediate enhanced antitumor responses, the former as a standalone treatment, the latter in conjunction with an anti-TAA mAb. To further characterize the CD47lowxPD-L1 and CD47highxPD-L1 bsAbs, lead candidates will be tested in PK and tolerability studies in non-human primates.

References

Fischer N, Elson G, Magistrelli G, Dheilly E, Fouque N, Laurendon A, et al. Exploiting light chains for the scalable generation and platform purification of native human bispecific IgG. Nat Commun 2015 May;6(1):6113.

Post-acute delivery of α5-GABAA antagonist, S 44819, improves functional recovery in juvenile rats following stroke

Hypo-excitability was reported in the peri-infarct tissue following stroke, an effect counteracted by a blockage of α5-GABAA receptors in adult rodents. Our present study aims to evaluate the effect of a selective α5-GABAA receptor antagonist, S 44819, in stroke in juvenile animals. We have set up and characterized an original model of transient ischemic stroke in 28 day-old Sprague-Dawley rats (45-min occlusion of the middle cerebral artery by intraluminal suture). In this model, S 44819 (1, 3 and 10 mg/kg, b.i.d) was orally administered from day 3 to day 16 after stroke onset. Sensorimotor recovery was assessed on day 1, day 9 and day 16 after stroke onset. Results show that rats treated with S 44819 at the doses of 3 and 10 mg/kg displayed a significant improvement of the neurological deficits (neuroscore) on day 9 and day 16, when compared with animals treated with vehicle. Grip-test data analysis reveals that rats treated with S 44819 at the dose of 3 mg/kg displayed a better recovery on day 9 and day 16. These results are in agreement with those previously observed in adult rats, demonstrating that targeting α5-GABAA receptors improves neurological recovery after stroke in juvenile rats.

Uncertainty calculation methodologies in microflow measurements: Comparison of GUM, GUM-S1 and Bayesian approach

The importance of measurement quality cannot be over emphasized in medical applications, as one is dealing with life issues and the wellbeing of society, from oncology to new-borns, and more recently to patients of the COVID-19 pandemic. In all these dire situations, the accuracy of fluid delivered according to a prescribed dose can be critical. Microflow applications are growing in importance for a wide variety of scientific fields, namely drug development and administration, Organ-on-a-Chip, or bioanalysis, but accurate and reliable measurements are a tough challenge in micro-to-femto flow operating ranges, from 2.78 × 10^-4 mL/s down to 2.78 × 10^-7 mL/s (1000 μL/h down to 1 μL/h). Several sources of error have been established such as the mass measurement, the fluid evaporation dependent on the gravimetric methodology implemented, the tube adsorption and the repeatability, believed to be closely related to the operating mode of the stepper motor and drive screw pitch of a syringe pump. In addition, the difficulty in dealing with microflow applications extends to the evaluation of measurement uncertainty which will qualify the quality of measurement. This is due to the conditions entailed when measuring very small values, close to zero, of a quantity such as the flow rate which is inherently positive. Alternative methods able to handle these features were developed and implemented, and their suitability will be discussed.

Teratomatous Elements in Orchiectomy Specimens Are Associated with a Reduced Relapse-Free Survival in Metastasized Testicular Germ Cell Tumors

INTRODUCTION

The impact of teratomatous elements in orchiectomy specimens of metastasized testicular germ cell tumors (TGCT) regarding oncological outcome is still unclear.

METHODS

We performed a retrospective analysis including 146 patients with metastasized TGCT analysing patient characteristics.

RESULTS

Twenty-six (18%) of all patients showed teratomatous elements in the orchiectomy specimens. TGCT with teratomatous elements showed a significantly higher frequency of clinical-stage 2C-3 disease (73 vs. 49%, p = 0.031), visceral metastases (58 vs. 32%, p = 0.015), and poor prognosis (p = 0.011) than TGCT without teratomatous elements. Teratoma-containing TGCT revealed a significantly higher rate of post-chemotherapy retroperitoneal lymph node dissection (PC-RPLND, 54 vs. 32%, p = 0.041), with teratomatous elements being more often present in the PC-RPLND specimens (43 vs. 11%, p = 0.020) than nonteratoma-containing primaries. In the Kaplan-Meier estimates, the presence of teratomatous elements in orchiectomy specimens was associated with a significantly reduced relapse-free survival (RFS) (p = 0.049) during a median follow-up of 36 months (10-115.5).

CONCLUSIONS

The presence of teratomatous elements in orchiectomy specimens is associated with an advanced tumor stage, worse treatment response as well as a reduced RFS in metastasized TGCT. Consequently, the presence of teratomatous elements might act as a reliable stratification tool for treatment decision in TGCT patients.

Deep Learning Based Instance Segmentation of Titanium Dioxide Particles in the Form of Agglomerates in Scanning Electron Microscopy

The size characterization of particles present in the form of agglomerates in images measured by scanning electron microscopy (SEM) requires a powerful image segmentation tool in order to properly define the boundaries of each particle. In this work, we propose to use an algorithm from the deep statistical learning community, the Mask-RCNN, coupled with transfer learning to overcome the problem of generalization of the commonly used image processing methods such as watershed or active contour. Indeed, the adjustment of the parameters of these algorithms is almost systematically necessary and slows down the automation of the processing chain. The Mask-RCNN is adapted here to the case study and we present results obtained on titanium dioxide samples (non-spherical particles) with a level of performance evaluated by different metrics such as the DICE coefficient, which reaches an average value of 0.95 on the test images.

Evaluation of Plasma C-Reactive Protein as a Biomarker in Dogs with Atopic -Dermatitis Receiving Allergen-Specific Immunotherapy: A Pilot Study

INTRODUCTION

In this pilot study, we wished to determine if C-reactive protein (CRP) levels could be a useful severity or treatment biomarker for canine atopic dermatitis (AD). Nine atopic dogs received allergen immunotherapy for 1 year. Blood was collected before and at four re-evaluation visits. At each time point, the skin lesions were graded with the Canine Atopic Dermatitis Extent and Severity Index (CADESI) 4, and the plasma CRP levels were measured by Enzyme-linked Immunosorbent Assay (ELISA). We found a significant yet minimal correlation between the CRP levels and the CADESI4 scores. The CRP levels were not significantly different between dogs with AD of increasing severity. Finally, there was no correlation between the percentage change in CADESI4 and CRP values during immunotherapy. In conclusion, the lack of significant difference in CRP levels between dogs of increasing AD severity and lack of correlation between percentage changes in skin lesion and CRP values suggest that this protein would not be a clinically-useful biomarker in atopic dogs.

Sexual Satisfaction in Older Heterosexual Couples From Four European Countries: Exploring the Roles of Actual and Perceived Discrepancy in Sexual Interest

Even though sexual activity frequently takes place with another person, research rarely focuses on how partners influence each other's sexual lives. This study used the sexual dyad to compare the concept of actual versus perceived discrepancy in sexual interest and explored how each is related to older partnered individuals' sexual satisfaction. Further, the study assessed the robustness of the association between sexual interest discrepancy and sexual satisfaction, if any, by controlling for emotional intimacy. The actor-partner interdependence model (APIM) using structural equation modeling (SEM) was applied to examine 677 heterosexual couples ages 60 to 75 in Norway, Denmark, Belgium, and Portugal. Although a couple's actual discrepancy in sexual interest was not predictive of female and male partners' sexual satisfaction, perceived discrepancy was negatively associated with sexual satisfaction in both partners after controlling for emotional intimacy. This indicates that the subjective feelings of being sexually dissimilar seem to be more important to sexual satisfaction than the actual mismatch among partners in older heterosexual couples. Moreover, the finding that emotional intimacy is linked with sexual satisfaction underscores the importance of a broader perspective on sexuality among older adults.

Clinical characteristics and outcome of patients over 60 years with Hodgkin lymphoma treated in Switzerland

Hodgkin lymphoma (HL) in older patients appears to be a different disease compared with younger patients with historically lower survival rates. This is related to a variety of factors, including increased treatment-related toxicity, the presence of comorbidities, and biologic differences. In order to better assess the clinical characteristics, treatment strategies, and outcome of this particular population, we conducted a population-based, retrospective analysis including 269 patients with HL older than 60 years (median age 71 years, range 60-94), treated between 2000 and 2017 in 15 referral centers across Switzerland. Primary endpoints were overall survival (OS), progression-free survival (PFS), and cause-specific survival (CSS). The vast majority of patients were treated with curative intent, either with a combined modality approach (chemotherapy followed by radiation therapy) or with systemic therapy. At a median follow-up of 6.6 years (95% confidence interval [CI], 6.0-7.6), 5-year PFS was 52.2% (95% CI, 46.0-59.2), 5-year OS was 62.5% (95% CI, 56.4-69.2), and 5-year CSS was 85.1.8% (95% CI, 80.3-90.1) for the entire cohort. A significant difference in terms of CSS was observed for patients older than 71 years in comparison to patients aged 60-70 years (hazard ratio 2.6, 1.3-5.0, p = 0.005). Bleomycin-induced lung toxicity (BLT) was documented in 26 patients (17.7%) out of the 147 patients exposed to this compound and was more frequent in patients older than 71 years (15/60, 25%). Outcome of HL pts older than 71 years appeared to decrease substantially in comparison to the younger counterpart. Treatment-related toxicities appeared to be relevant, in particular, BLT. New, potentially less toxic strategies need to be investigated in prospective clinical trials in this particular frail population.

Dual-Time Point [68Ga]Ga-PSMA-11 PET/CT Hybrid Imaging for Staging and Restaging of Prostate Cancer

Simple Summary

Early diagnosis and tumor characterization of prostate cancer (PCa) are important for accurate treatment. [⁶⁸Ga]Ga-PSMA-11 PET/CT turns out to constitute a major step toward improved diagnostic procedures to detect primary, recurrent, and metastatic PCa. The aim of our study is to evaluate the effect of a second imaging modality for the staging and restaging of PCa by possibly detecting additional PCa lesions due to the well-known increase of PSMA uptake over time. There was a significant increase in tracer uptake on delayed images in comparison to early [⁶⁸Ga]Ga-PSMA-11 PET/CT in our study, but the lesion positivity rate was comparable. However, in a few individual cases, additional delayed scans provided an information advantage in PCa lesion detection. The findings of our study are likely to be of major interest to clinicians as well as to researchers defining the algorithms that are necessary to implement this promising method with its specific tracer into clinical routine.

Abstract

Routine [⁶⁸Ga]Ga-PSMA-11 PET/CT (one hour post-injection) has been shown to accurately detect prostate cancer (PCa) lesions. The goal of this study is to evaluate the benefit of a dual-time point imaging modality for the staging and restaging of PCa patients. Biphasic [⁶⁸Ga]Ga-PSMA-11 PET/CT of 233 patients, who underwent early and late scans (one/three hours post-injection), were retrospectively studied. Tumor uptake and biphasic lesion detection for 215 biochemically recurrent patients previously treated for localized PCa (prostatectomized patients (P-P)/irradiated patients (P-I) and 18 patients suspected of having primary PCa (P-T) were separately evaluated. Late [⁶⁸Ga]Ga-PSMA-11 PET/CT imaging detected 554 PCa lesions in 114 P-P patients, 187 PCa lesions in 33 P-I patients, and 47 PCa lesions in 13 P-T patients. Most patients (106+32 P-P/P-I, 13 P-T) showed no additional PCa lesions. However, 11 PSMA-avid lesions were only detected in delayed images, and 33 lesions were confirmed as malignant by a SUVmax increase. The mean SUVmax of pelvic lymph node metastases was 25% higher (p < 0.001) comparing early and late PET/CT. High positivity rates from routine [⁶⁸Ga]Ga-PSMA-11 PET/CT for the staging and restaging of PCa patients were demonstrated. There was no decisive influence of additional late imaging with PCa lesion detection on therapeutic decisions. However, in a few individual cases, additional delayed scans provided an information advantage in PCa lesion detection due to higher tracer uptake and improved contrast.

Mechanisms underlying the association between perceived discrepancy in sexual interest and sexual satisfaction among partnered older adults in four European countries

The ways in which the discrepancy between one's own interest in sex and that of one's partner may affect personal sexual satisfaction has rarely been systematically studied, especially among older adults. Previous research among younger adults indicates that a discrepancy in sexual desire can be detrimental in terms of several relationship outcomes, including sexual satisfaction. This study aimed to investigate a conceptual model of sexual satisfaction among coupled older adults which posits that the association between perceived discrepancy in sexual interest and sexual satisfaction is mediated by the frequency of sexual activity and emotional closeness during sex. Data from a probability-based postal survey that included 2695 partnered heterosexual adults aged 60-75 years from four European countries (Norway, Denmark, Belgium, and Portugal) were used to test the mediation model. Due to expected gender differences in the two mediators, all analyses were carried out separately for men and women. The findings supported the proposed model, suggesting that as an individual's perception of a discrepancy in sexual interest increases, his or her levels of sexual frequency and perceived closeness during sex decrease-which in turn diminishes sexual satisfaction. The results of this study provide insights into links among sexual interest, sexual frequency, emotional closeness, and sexual satisfaction in older adults, and point to substantial similarities in the sexuality of aging men and women in this regard.

Impact of the COVID-19 Pandemic on Urologists in Germany

Background

In order to contain the coronavirus disease 2019 (COVID-19) pandemic, Germany has implemented drastic restrictions on public or social life, while health institutions are invoked to postpone elective procedures. Although urologists are less involved in the direct treatment of COVID-19 patients, the current situation strongly affects the urological work routine.

Objective

To analyze the impact of the COVID-19 pandemic on various aspects of work and personal life among urologists in Germany.

Design, setting, and participants

A total of 589 urologists in Germany participated in an online survey between March 27 and April 11, 2020.

Outcome measurements and statistical analysis

Participants were stratified into subgroups according to professional characteristics.

Results and limitations

Most urologists rated Germany as “well prepared” and the increasing restrictions of social life as “very positive.” Routine operation was more restricted in hospitals than in the outpatient sector (p = 0.046). Moreover, urologists from the outpatient sector felt significantly less prepared for the COVID-19 pandemic (p = 0.001), reported a higher shortage of protective medical equipment (p < 0.001), and described a tendency toward a higher level of threat (p = 0.054). Although restrictions regarding telemedicine approaches were reported by 60% of participants, the outpatient sector used telehealth more frequently than hospitals (25.5% vs 17.0%, p < 0.001). Limitations include the national design and the restricted survey period.

Conclusions

This survey systematically evaluates the impact of the COVID-19 pandemic on personal and professional aspects of German urologists. We identified several issues, such as a higher shortage of medical protective equipment in the outpatient sector that could trigger specific measures to further improve the quality of urological care in Germany.

Patient summary

We evaluated a potential impact of the coronavirus disease 2019 (COVID-19) pandemic on professional and personal aspects of the urologists in Germany. Our results suggest that the outpatient sector should receive specific attention as, for example, shortage of protective equipment was more common.

Effect of glucose and insulin supplementation on the isolation of primary human hepatocytes

Primary human hepatocytes (PHHs) remain the gold standard for in vitro investigations of xenobiotic metabolism and hepatotoxicity. However, scarcity of liver tissue and novel developments in liver surgery has limited the availability and quality of tissue samples. In particular, warm ischemia shifts the intracellular metabolism from aerobic to anaerobic conditions, which increases glycogenolysis, glucose depletion and energy deficiency. Therefore, the aim of the present study was to investigate whether supplementation with glucose and insulin during PHH isolation could reconstitute intracellular glycogen storage and beneficially affect viability and functionality. Furthermore, the study elucidated whether the susceptibility of the tissue's energy status correlates with body mass index (BMI). PHHs from 12 donors were isolated from human liver tissue obtained from partial liver resections using a two-step EDTA/collagenase perfusion technique. For a direct comparison of the influence of glucose/insulin supplementation, we modified the setup, enabling the parallel isolation of two pieces of one tissue sample with varying perfusate. Independent of the BMI of the patient, the glycogen content in liver tissue was notably low in the majority of samples. Furthermore, supplementation with glucose and insulin had no beneficial effect on the glycogen concentration of isolated PHHs. However, an indirect improvement of the availability of energy was shown by increased viability, plating efficiency and partial cellular activity after supplementation. The plating efficiency showed a striking inverse correlation with increasing lipid content of PHHs. However, 60 h of cultivation time revealed no significant impact on the maintenance of albumin and urea synthesis or xenobiotic metabolism after supplementation. In conclusion, surgical procedures and tissue handling may decrease hepatic energy resources and lead to cell stress and death. Consequently, PHHs with low energy resources die during the isolation process without supplementation of glucose/insulin or early cell culture, while their survival rates are improved with glucose/insulin supplementation.

Radiation Dose in Prostatic Artery Embolization Using Cone-Beam CT and 3D Roadmap Software

PURPOSE

To evaluate the radiation dose in patients undergoing prostatic artery embolization (PAE) using cone-beam CT and 3-dimensional (3D) guidance software.

MATERIALS AND METHODS

In this single-center retrospective study, 100 patients with benign prostatic hyperplasia (mean prostate volume, 83.6 mL ± 44.2; 69.4 ± 9.6 years of age; body mass index, 26.5 ± 4.2) were treated using PAE between October 2016 and April 2018. Informed consent was obtained from all participants included in the study. All patients received at least 1 intraprocedural cone-beam CT per side for evaluation of the vessel anatomy and software rendering of 3D guidance for catheter guidance. Digital subtraction angiography (DSA) was performed in the distal branches only. The total dose area product (DAP), along with the DAP attributed to fluoroscopy, DSA, and cone-beam CT, were assessed.

RESULTS

Bilateral embolization was achieved in 83 patients (83%). The average total DAP was 134.4 Gy ⋅ cm² ± 69.5 (range, 44.7-410.9 Gy ⋅ cm²). Fluoroscopy, DSA, and cone-beam CT accounted for 35.5 Gy ⋅ cm² ± 21.3 (range, 8.6-148.6 Gy ⋅ cm²) or 26.4% (percentage of total DAP), 58.2 Gy ⋅ cm² ± 48.3 (range, 10.3-309.3 Gy ⋅ cm²) or 43.3%, and 40.7 Gy ⋅ cm² ± 14.5 (range, 15.9-86.3 Gy ⋅ cm²) or 30.3%, respectively. Average procedure time was 89.4 ± 27.0 minutes, and the average fluoroscopy time was 30.9 ± 12.2 minutes.

CONCLUSIONS

Intraprocedural cone-beam CT in combination with 3D guidance software allows for identification and catheterization of the prostatic artery in PAE. Furthermore, the results of this trial indicate that this study protocol may lead to a low overall radiation dose.

Abstract 546: Selectively targeting CD47 with bispecific antibody to efficiently eliminate mesothelin-positive solid tumors

The CD47- signal regulatory protein α (SIRPα) axis, originally discovered as a mechanism of self-recognition, has emerged as a novel innate immune check-point employed by cancer cells to escape immune surveillance. Over-expression of CD47 on a plethora of hematologic and solid cancers has been shown to be associated with poor prognosis. CD47 blockade is thus considered as an attractive strategy to retune the host immune system toward eliminating cancer cells. Clinical efficacy has been achieved in patients with Non-Hodgkin lymphoma (NHL) treated with a combination of the anti-CD20 monoclonal antibody (mAb), rituximab, and the anti-CD47 mAb, Hu5F9-G4. However, in parallel, due to the ubiquitous expression of CD47 on healthy cells, toxicity is observed limiting exposure which impairs clinical development of anti-CD47 mAbs.

To harness the tumoricidal potential and avoid the liabilities of CD47 blockade, we have developed bispecific antibodies (bsAbs), co-targeting CD47 and a tumor associated antigen (TAA), for selective blockade of CD47 on malignant cells. Mesothelin (MSLN) has been selected as one of these TAAs as it is over-expressed on multiple types of solid tumors. An anti-CD47xMSLN bsAb with a fully functional IgG1 Fc domain has been generated and tested for efficacy and safety in vitro and in vivo using cell-based assays and animal models.

With a panel of human MSLN+ target cells, the bsAb kills more efficiently through Ab-dependent cellular phagocytosis (ADCP) and cell-mediated cytotoxicity (ADCC) as compared to the anti-MSLN mAb, amatuximab. Efficacy of the bsAb was minimally affected by soluble MSLN as compared to amatuximab. Mechanistic studies demonstrated that the increased ADCP and ADCC were due to co-engagement-mediated blockade of both target proteins. In vivo using xenograft models, whereas amatuximab was unable, the bsAb inhibited tumor growth of OVCAR3 and MSLN-transfected HepG2 cell lines. Phenotypic analysis showed that treatment with the bsAb induced the accumulation of myeloid cells with increased F4/80 expression in the tumor microenvironment. Importantly, the bsAb was well-tolerated in an exploratory four-week repeated dose study at the highest dose tested (10 mg/kg) in cynomolgus monkeys.

Conclusion: Selective CD47 targeting on tumor cells with an anti-CD47xMSLN bsAb showed efficient killing of MSLN+ tumor cells in vitro and in vivo. A study in non-human primates administered weekly a therapeutically relevant dose over 28 days was well tolerated demonstrating no adverse hematological profiles.

Citation Format: Limin Shang, Vanessa Buatois, Eric Hatterer, Xavier Chauchet, Hasnaà Haddouk, Stefano Majocchi, Krzysztof Masternak, Marie H. Kosco-Vilbois, Nicolas Fischer, Walter G. Ferlin. Selectively targeting CD47 with bispecific antibody to efficiently eliminate mesothelin-positive solid tumors [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 546.

Readout-Segmented Echo-Planar DWI for the Detection of Cholesteatomas: Correlation with Surgical Validation

BACKGROUND AND PURPOSE

MR imaging has become an important tool for the detection of cholesteatomas of the middle ear. Various diffusion-weighted imaging sequences are available and have shown promising results. This study aimed to evaluate readout-segmented echo-planar DWI for the detection of cholesteatoma and compare the results with surgical validation.

MATERIALS AND METHODS

Fifty patients with chronic otitis media (24 females and 26 males; range, 12-76 years of age; mean age, 41 years) who underwent MR imaging before an operation of the middle ear (1-169 days) were included. The MR imaging protocol consisted of axial and coronal readout-segmented echo-planar DWI with b-values of 0 and 1000 s/mm² and 3-mm slice thickness. The readout-segmented echo-planar diffusion-weighted images were fused with standard T2-weighted sequences for better anatomic assignment. The results of the MR imaging evaluation were correlated with the results from the operation.

RESULTS

Readout-segmented echo-planar DWI detected 22 of the 25 cases of surgically proved cholesteatoma. It has an accuracy of 92% (95% confidence interval, 80.8%-97.8%), a sensitivity of 88%, a specificity of 96%, a positive predictive value of 96%, and a negative predictive value of 89%. In 1 case, a positive finding for cholesteatoma with readout-segmented echo-planar DWI could not be proved by histology, and in 3 cases, histology yielded a cholesteatoma that was not detected with MR imaging.

CONCLUSIONS

Readout-segmented echo-planar DWI is a promising and reliable MR imaging sequence for the detection and exclusion of cholesteatoma.

Stabilized Low-n Amyloid-β Oligomers Induce Robust Novel Object Recognition Deficits Associated with Inflammatory, Synaptic, and GABAergic Dysfunction in the Rat

BACKGROUND

With current treatments for Alzheimer's disease (AD) only providing temporary symptomatic benefits, disease modifying drugs are urgently required. This approach relies on improved understanding of the early pathophysiology of AD. A new hypothesis has emerged, in which early memory loss is considered a synapse failure caused by soluble amyloid-β oligomers (Aβo). These small soluble Aβo, which precede the formation of larger fibrillar assemblies, may be the main cause of early AD pathologies.

OBJECTIVE

The aim of the current study was to investigate the effect of acute administration of stabilized low-n amyloid-β1-42 oligomers (Aβo1-42) on cognitive, inflammatory, synaptic, and neuronal markers in the rat.

METHODS

Female and male Lister Hooded rats received acute intracerebroventricular (ICV) administration of either vehicle or 5 nmol of Aβo1-42 (10μL). Cognition was assessed in the novel object recognition (NOR) paradigm at different time points. Levels of inflammatory (IL-1β, IL-6, TNF-α), synaptic (PSD-95, SNAP-25), and neuronal (n-acetylaspartate, parvalbumin-positive cells) markers were investigated in different brain regions (prefrontal and frontal cortex, striatum, dorsal and ventral hippocampus).

RESULTS

Acute ICV administration of Aβo1-42 induced robust and enduring NOR deficits. These deficits were reversed by acute administration of donepezil and rolipram but not risperidone. Postmortem analysis revealed an increase in inflammatory markers, a decrease in synaptic markers and parvalbumin containing interneurons in the frontal cortex, with no evidence of widespread neuronal loss.

CONCLUSION

Taken together the results suggest that acute administration of soluble low-n Aβo may be a useful model to study the early mechanisms involved in AD and provide us with a platform for testing novel therapeutic approaches that target the early underlying synaptic pathology.

Biopiracy versus One-World Medicine-From colonial relicts to global collaborative concepts

BACKGROUND

Practices of biopiracy to use genetic resources and indigenous knowledge by Western companies without benefit-sharing of those, who generated the traditional knowledge, can be understood as form of neocolonialism.

HYPOTHESIS

The One-World Medicine concept attempts to merge the best of traditional medicine from developing countries and conventional Western medicine for the sake of patients around the globe.

STUDY DESIGN

Based on literature searches in several databases, a concept paper has been written. Legislative initiatives of the United Nations culminated in the Nagoya protocol aim to protect traditional knowledge and regulate benefit-sharing with indigenous communities. The European community adopted the Nagoya protocol, and the corresponding regulations will be implemented into national legislation among the member states. Despite pleasing progress, infrastructural problems of the health care systems in developing countries still remain. Current approaches to secure primary health care offer only fragmentary solutions at best. Conventional medicine from industrialized countries cannot be afforded by the impoverished population in the Third World. Confronted with exploding costs, even health systems in Western countries are endangered to burst. Complementary and alternative medicine (CAM) is popular among the general public in industrialized countries, although the efficacy is not sufficiently proven according to the standards of evidence-based medicine. CAM is often available without prescription as over-the-counter products with non-calculated risks concerning erroneous self-medication and safety/toxicity issues. The concept of integrative medicine attempts to combine holistic CAM approaches with evidence-based principles of conventional medicine.

CONCLUSION

To realize the concept of One-World Medicine, a number of standards have to be set to assure safety, efficacy and applicability of traditional medicine, e.g. sustainable production and quality control of herbal products, performance of placebo-controlled, double-blind, randomized clinical trials, phytovigilance, as well as education of health professionals and patients.

Round optimization for improved discovery of native bispecific antibodies

The assembly of bispecific antibodies (bsAb) that retain the structure of a standard IgG can be challenging as the correct pairing of the different heavy and light chains has to be ensured while unwanted side products kept to a minimum. The use of antibodies sharing a common chain facilitates assembly of such bsAb formats but requires additional efforts during the initial discovery phase. We have developed a native bsAb format called κλ body based on antibodies that, while being specific for different antigens, share the same heavy chain. Such antibodies can readily be isolated from antibody libraries incorporating a single VH combined with light chain diversity. However, in order to improve the discovery process of such fixed VH antibodies, we developed a method to optimize populations of light chains by recovering and shuffling CDRL3 sequences that have been enriched for antigen binding by phage display selection. This approach allowed for the isolation of a more diverse and potent panel of antibodies blocking the interaction between PD-1 and PD-L1 when compared to our standard in vitro selection approach, thus providing better building blocks for subsequent bsAb generation.

Abstract A088: Selective blockage of the innate immune checkpoint receptor CD47 on mesothelin (MSLN) positive solid tumor cells via dual targeting bispecific antibodies alters the tumor microenvironment to control tumor growth

Up-regulation of CD47 is an immune evasion mechanism used by different cancers to evade immune surveillance. Through its interaction with signal-regulatory protein alpha (SIRPα) on myeloid cells, CD47 delivers a universal “don’t eat me” signal to phagocytes, which prevents immune cells from efficiently eliminating tumor cells. Blockade of the SIRPα–CD47 innate immune checkpoint has therefore emerged as a new way to treat cancer. Several CD47-targeting molecules are in development with encouraging results obtained with monoclonal antibodies (mAb). However, the pharmacologic properties and the safety profile of molecules indiscriminately blocking CD47 can be improved by selectively inhibiting CD47 only on tumor cells. For this purpose, we generated bispecific antibodies (bsAbs) capable of targeting blockade of CD47 specifically to malignanT-cells through the co-engagement of a tumor-associated antigen (TAA). The bsAb NI-1801 specifically targets mesothelin (MSLN)-positive tumors. NI-1801 was shown to bind to MSLN-positive tumor cells, but not to MSLN-negative cells expressing physiologic levels of CD47 (e.g., leukocytes, erythrocytes, platelets). NI-1801 blocks the CD47-SIRPα interaction in a MSLN-dependent manner and thus minimizes the side effects related to a nonspecific blockade of CD47 on healthy cells. Studying antibody-dependent cellular phagocytosis (ADCP) and antibody-dependent cellular cytotoxicity (ADCC) of various MSLN-positive human tumor cell lines revealed that NI-1801 markedly enhanced killing as compared to amatuximab (an anti-MSLN mAb in clinical trials) and to the corresponding anti-MSLN mAb, exemplifying the role of blocking the “don’t eat me” signal to target cancer. NI-1801 also showed efficacy in various xenograft tumor models and analysis of the tumor microenvironment (TME) revealed a significant increase in leukocyte subpopulations (macrophages/monocytes and NK cells) of NI-1801 treated mice, suggesting that NI-1801 mediates the recruitment of monocytes from blood. Additionally, NI-1801 treatment affected the ratio between MHC-II-low and MHC-II-high macrophages in the TME. Finally, nonhuman primate studies with NI-1801 demonstrated a linear elimination profile, minimal target-mediated drug disposition and no hematologic toxicity. Taken together, these results illustrate that this strategy possesses potent anticancer activities both in vitro and in vivo in conjunction with favorable pharmacologic and toxicologic profiles.

Citation Format: Stefano Majocchi, Valéry Moine, Xavier Chauchet, Lucile Broyer, Laura Cons, Laurence Chatel, Eric Hatterer, Vanessa Buatois, Hasnaà Haddouk, Gérard Didelot, Giovanni Magistrelli, Yves Poitevin, Ulla Ravn, Anne Papaioannou, Françoise Richard, Limin Shang, Marie H. Kosco-Vilbois, Nicolas Fischer, Walter G. Ferlin, Krzysztof Masternak. Selective blockage of the innate immune checkpoint receptor CD47 on mesothelin (MSLN) positive solid tumor cells via dual targeting bispecific antibodies alters the tumor microenvironment to control tumor growth [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr A088.

Design and assembly of a chemically switchable and fluorescently traceable light-driven proton pump system for bionanotechnological applications

Energy-supplying modules are essential building blocks for the assembly of functional multicomponent nanoreactors in synthetic biology. Proteorhodopsin, a light-driven proton pump, is an ideal candidate to provide the required energy in form of an electrochemical proton gradient. Here we present an advanced proteoliposome system equipped with a chemically on-off switchable proteorhodopsin variant. The proton pump was engineered to optimize the specificity and efficiency of chemical deactivation and reactivation. To optically track and characterize the proteoliposome system using fluorescence microscopy and nanoparticle tracking analysis, fluorescenlty labelled lipids were implemented. Fluorescence is a highly valuable feature that enables detection and tracking of nanoreactors in complex media. Cryo-transmission electron microscopy, and correlative atomic force and confocal microscopy revealed that our procedure yields polylamellar proteoliposomes, which exhibit enhanced mechanical stability. The combination of these features makes the presented energizing system a promising foundation for the engineering of complex nanoreactors.

0Phobia - towards a virtual cure for acrophobia: study protocol for a randomized controlled trial

BACKGROUND

Virtual reality exposure therapy (VRET) has been shown to be as effective as traditional forms of in vivo exposure therapy for the treatment of specific phobias. However, as with in vivo exposure, VRET still involves relatively high costs and limited accessibility which makes it prohibitive for a large part of the population. Innovative methods using smartphone applications (apps) may improve accessibility and scalability of VRET. The aim of this study is to evaluate 0Phobia, a gamified self-guided VRET for acrophobia that is delivered through a smartphone app in combination with rudimentary cardboard virtual reality (VR) goggles.

METHODS/DESIGN

Participants (N = 180, aged 18-65 years) with acrophobia symptoms will be recruited from the Dutch general population and randomized to either 0Phobia (n = 90) or a waitlist control condition (n = 90). 0Phobia will be delivered over a period of 3 weeks and includes psychoeducation, VR exposure, cognitive techniques, monitoring of symptoms, and relapse prevention. The primary outcome measure will be the Acrophobia Questionnaire. Secondary outcome measures will include user-friendliness, symptoms of anxiety, depression, and mastery. Assessments will take place online at baseline, directly after the intervention (post test) and at follow-up (3 months).

DISCUSSION

This study capitalizes on novel technology and recent scientific advances to develop an affordable and scalable treatment modality.

TRIAL REGISTRATION

Netherlands Trial Register: NTR6442 . Registered on 29 June 2017.

Replicability of Physical Exercise Interventions in Lung Transplant Recipients; A Systematic Review

Introduction: This systematic review aimed to assess the replicability of physical exercise interventions in lung transplantation patients. For replicability we focused on (1) the description of training principles, (2) the description of FITT components and adherence to the interventions, (3) the amount of detailed information given on the physical exercise intervention, and (4) reporting the methodological quality of the included works.

Methods: Relevant databases (Medline-Ovid, EMBASE, CINAHL, PsychInfo, Cochrane Library) were searched. Author dyads selected and systematically analyzed the included studies independent from each other. A purpose developed checklist was used to assess the details of the exercise interventions and their methodological quality.

Results: From the seven included manuscripts, three described resistance training, one endurance, and three combined training approaches. All manuscripts reported specificity and initial values, six manuscripts mention progression and overload. The exercise principle reversibility was reported once and diminishing returns was not reported at all. All studies reported the type of exercise, three studies reported intensity and one study reported time for training. Not any study completely reported frequency or described adherence to the intervention. Lack of detailed reporting was identified as the cause for murky description of the interventions. The highest score for intervention description was 5 of possible 12 items.

Conclusions: Replicability of many exercise interventions in LTX is not warranted due too poor descriptions of important items related to training. In particular there were insufficiently detailed reporting of training principles and FITT components in programs developed for LTX. Future interventions that aim to train LTX patients should spent effort in writing reports in which the intervention is detailed to such an extent that full replicability in clinical settings can be guaranteed.

Prevention from radiation damage by natural products

BACKGROUND

Radiotherapy is a mainstay of cancer treatment since decades. Ionizing radiation (IR) is used for destruction of cancer cells and shrinkage of tumors. However, the increase of radioresistance in cancer cells and radiation toxicity to normal tissues are severe concerns. The exposure to radiation generates intracellular reactive oxygen species (ROS), which leads to DNA damage by lipid peroxidation, removal of thiol groups from cellular and membrane proteins, strand breaks and base alterations.

HYPOTHESIS

Plants have to deal with radiation-induced damage (UV-light of sun, other natural radiation sources). Therefore, it is worth speculating that radioprotective mechanisms have evolved during evolution of life. We hypothesize that natural products from plants may also protect from radiation damage caused as adverse side effects of cancer radiotherapy.

METHODS

The basis of this systematic review, we searched the relevant literature in the PubMed database.

RESULTS

Flavonoids, such as genistein, epigallocatechin-3-gallate, epicatechin, apigenin and silibinin mainly act as antioxidant, free radical scavenging and anti-inflammatory compounds, thus, providing cytoprotection in addition to downregulation of several pro-inflammatory cytokines. Comparable effects have been found in phenylpropanoids, especially caffeic acid phenylethylester, curcumin, thymol and zingerone. Besides, resveratrol and quercetin are the most important cytoprotective polyphenols. Their radioprotective effects are mediated by a wide range of mechanisms mainly leading to direct or indirect reduction of cellular stress. Ascorbic acid is broadly used as antioxidant, but it has also shown activity in reducing cellular damage after irradiation mainly due to its antioxidant capabilities. The metal ion chelator, gallic acid, represents another natural product attenuating cellular damage caused by radiation.

CONCLUSIONS

Some secondary metabolites from plants reveal radioprotective features against cellular damage caused by irradiation. These results warrant further analysis to develop phytochemicals as radioprotectors for clinical use.

Preclinical Development of a Bispecific Antibody that Safely and Effectively Targets CD19 and CD47 for the Treatment of B-Cell Lymphoma and Leukemia

CD47, an ubiquitously expressed innate immune checkpoint receptor that serves as a universal "don't eat me" signal of phagocytosis, is often upregulated by hematologic and solid cancers to evade immune surveillance. Development of CD47-targeted modalities is hindered by the ubiquitous expression of the target, often leading to rapid drug elimination and hemotoxicity including anemia. To overcome such liabilities, we have developed a fully human bispecific antibody, NI-1701, designed to coengage CD47 and CD19 selectively on B cells. NI-1701 demonstrates favorable elimination kinetics with no deleterious effects seen on hematologic parameters following single or multiple administrations to nonhuman primates. Potent in vitro and in vivo activity is induced by NI-1701 to kill cancer cells across a plethora of B-cell malignancies and control tumor growth in xenograft mouse models. The mechanism affording maximal tumor growth inhibition by NI-1701 is dependent on the coengagement of CD47/CD19 on B cells inducing potent antibody-dependent cellular phagocytosis of the targeted cells. NI-1701-induced control of tumor growth in immunodeficient NOD/SCID mice was more effective than that achieved with the anti-CD20 targeted antibody, rituximab. Interestingly, a synergistic effect was seen when tumor-implanted mice were coadministered NI-1701 and rituximab leading to significantly improved tumor growth inhibition and regression in some animals. We describe herein, a novel bispecific antibody approach aimed at sensitizing B cells to become more readily phagocytosed and eliminated thus offering an alternative or adjunct therapeutic option to patients with B-cell malignancies refractory/resistant to anti-CD20-targeted therapy. Mol Cancer Ther; 17(8); 1739-51. ©2018 AACR.

Tumor-Directed Blockade of CD47 with Bispecific Antibodies Induces Adaptive Antitumor Immunity

CD47 serves as an anti-phagocytic receptor that is upregulated by cancer to promote immune escape. As such, CD47 is the focus of intense immuno-oncology drug development efforts. However, as CD47 is expressed ubiquitously, clinical development of conventional drugs, e.g., monoclonal antibodies, is confronted with patient safety issues and poor pharmacology due to the widespread CD47 “antigen sink”. A potential solution is tumor-directed blockade of CD47, which can be achieved with bispecific antibodies (biAbs). Using mouse CD47-blocking biAbs in a syngeneic tumor model allowed us to evaluate the efficacy of tumor-directed blockade of CD47 in the presence of the CD47 antigen sink and a functional adaptive immune system. We show here that CD47-targeting biAbs inhibited tumor growth in vivo, promoting durable antitumor responses and stimulating CD8⁺ T cell activation in vitro. In vivo efficacy of the biAbs could be further enhanced when combined with chemotherapy or PD-1/PD-L1 immune checkpoint blockade. We also show that selectivity and pharmacological properties of the biAb are dependent on the affinity of the anti-CD47 arm. Taken together, our study validates the approach to use CD47-blocking biAbs either as a monotherapy or part of a multi-drug approach to enhance antitumor immunity.

Optimizing assembly and production of native bispecific antibodies by codon de-optimization

When production of bispecific antibodies requires the co-expression and assembly of three or four polypeptide chains, low expression of one chain can significantly limit assembly and yield. κλ bodies, fully human bispecific antibodies with native IgG structure, are composed of a common heavy chain and two different light chains, one kappa and one lambda. No engineering is applied to force pairing of the chains, thus both monospecific and bispecific antibodies are secreted in the supernatant. In this context, stoichiometric expression of the two light chains allows for maximal assembly of the bispecific antibody. In this study, we selected a κλ body with suboptimal characteristics due to low kappa chain expression. Codon optimization to increase expression of the kappa chain did not improve bispecific yield. Surprisingly, progressive introduction of non-optimal codons into the sequence of the lambda chain resulted in lowering its expression for an optimal tuning of the relative distribution of monospecific and bispecific antibodies. This codon de-optimization led to doubling of the κλ body yield. These results indicate that assembly of different proteins into a recombinant complex is an interconnected process and that reducing the expression of one polypeptide can actually increase the overall yield.

Controlled placement of multiple CNS cell populations to create complex neuronal cultures

In vitro brain-on-a-chip platforms hold promise in many areas including: drug discovery, evaluating effects of toxicants and pathogens, and disease modelling. A more accurate recapitulation of the intricate organization of the brain in vivo may require a complex in vitro system including organization of multiple neuronal cell types in an anatomically-relevant manner. Most approaches for compartmentalizing or segregating multiple cell types on microfabricated substrates use either permanent physical surface features or chemical surface functionalization. This study describes a removable insert that successfully deposits neurons from different brain areas onto discrete regions of a microelectrode array (MEA) surface, achieving a separation distance of 100 μm. The regional seeding area on the substrate is significantly smaller than current platforms using comparable placement methods. The non-permanent barrier between cell populations allows the cells to remain localized and attach to the substrate while the insert is in place and interact with neighboring regions after removal. The insert was used to simultaneously seed primary rodent hippocampal and cortical neurons onto MEAs. These cells retained their morphology, viability, and function after seeding through the cell insert through 28 days in vitro (DIV). Co-cultures of the two neuron types developed processes and formed integrated networks between the different MEA regions. Electrophysiological data demonstrated characteristic bursting features and waveform shapes that were consistent for each neuron type in both mono- and co-culture. Additionally, hippocampal cells co-cultured with cortical neurons showed an increase in within-burst firing rate (p = 0.013) and percent spikes in bursts (p = 0.002), changes that imply communication exists between the two cell types in co-culture. The cell seeding insert described in this work is a simple but effective method of separating distinct neuronal populations on microfabricated devices, and offers a unique approach to developing the types of complex in vitro cellular environments required for anatomically-relevant brain-on-a-chip devices.