The biased apelin receptor agonist, MM07, reverses Sugen/hypoxia-induced pulmonary arterial hypertension as effectively as the endothelin antagonist macitentan

Introduction: Pulmonary arterial hypertension (PAH) is characterised by endothelial dysfunction and pathological vascular remodelling, resulting in the occlusion of pulmonary arteries and arterioles, right ventricular hypertrophy, and eventually fatal heart failure. Targeting the apelin receptor with the novel, G protein-biased peptide agonist, MM07, is hypothesised to reverse the developed symptoms of elevated right ventricular systolic pressure and right ventricular hypertrophy. Here, the effects of MM07 were compared with the clinical standard-of-care endothelin receptor antagonist macitentan. Methods: Male Sprague-Dawley rats were randomised and treated with either normoxia/saline, or Sugen/hypoxia (SuHx) to induce an established model of PAH, before subsequent treatment with either saline, macitentan (30 mg/kg), or MM07 (10 mg/kg). Rats were then anaesthetised and catheterised for haemodynamic measurements, and tissues collected for histopathological assessment. Results: The SuHx/saline group presented with significant increases in right ventricular hypertrophy, right ventricular systolic pressure, and muscularization of pulmonary arteries compared to normoxic/saline controls. Critically, MM07 was as at least as effective as macitentan in significantly reversing detrimental structural and haemodynamic changes after 4 weeks of treatment. Discussion: These results support the development of G protein-biased apelin receptor agonists with improved pharmacokinetic profiles for use in human disease.

Efficient management of new patient referrals to a breast service: the safe introduction of an advanced nurse practitioner-led telephone breast pain service

INTRODUCTION

There has been an almost 100% increase in referrals to breast cancer diagnostic clinics in the past decade. Breaching of the two-week cancer referral target is now commonplace, potentially delaying diagnoses of breast malignancy in many women. Almost one in five of these referrals are women with mastalgia, not a symptom linked to breast cancer. The objective of the study was the safe introduction of an advanced nurse practitioner-led telephone service for women with mastalgia to improve the service for women and create capacity for those with "red flag" breast symptoms.

METHODS

Referrals to clinic were triaged, women with mastalgia only were directed to a telephone-based assessment clinic and symptoms evaluated using a multidisciplinary created proforma.

RESULTS

Within 23 months, 1,427 women were assessed in the breast pain telephone assessment clinic: 863 (61%) were aged over 40 and 564 (39%) aged under 40. A total of 1,238 underwent telephone assessment. Reassurance and discharge only was needed for 365 (26%). The aetiology of pain was identified as musculoskeletal in 1,104/1,238 (89%) of patients, with only 39/1,238 (3.2%) identified as having true breast pain. Additional symptoms were mentioned by 264 women (18%) during the consultation; all immediately redirected back to a diagnostic clinic. Mammography was undertaken in 609 women (43%). Seven women (0.6%) were diagnosed with a breast malignancy. Patient survey indicated that 93% of patients were satisfied with the care received and 97% said they would recommend the service to a family member or friend.

CONCLUSIONS

Although face-to-face assessments for breast pain remain the standard practice in many breast units, data indicating the safety of a telephone assessment clinic, along with high levels of patient satisfaction, question whether services can be delivered differently.

Side-by-side comparison of published small molecule inhibitors against thapsigargin-induced store-operated Ca2+ entry in HEK293 cells

Calcium (Ca2+) is a key second messenger in eukaryotes, with store-operated Ca2+ entry (SOCE) being the main source of Ca2+ influx into non-excitable cells. ORAI1 is a highly Ca2+-selective plasma membrane channel that encodes SOCE. It is ubiquitously expressed in mammals and has been implicated in numerous diseases, including cardiovascular disease and cancer. A number of small molecules have been identified as inhibitors of SOCE with a variety of potential therapeutic uses proposed and validated in vitro and in vivo. These encompass both nonselective Ca2+ channel inhibitors and targeted selective inhibitors of SOCE. Inhibition of SOCE can be quantified both directly and indirectly with a variety of assay setups, making an accurate comparison of the activity of different SOCE inhibitors challenging. We have used a fluorescence based Ca2+ addback assay in native HEK293 cells to generate dose-response data for many published SOCE inhibitors. We were able to directly compare potency. Most compounds were validated with only minor and expected variations in potency, but some were not. This could be due to differences in assay setup relating to the mechanism of action of the inhibitors and highlights the value of a singular approach to compare these compounds, as well as the general need for biorthogonal validation of novel bioactive compounds. The compounds observed to be the most potent against SOCE in our study were: 7-azaindole 14d (12), JPIII (17), Synta-66 (6), Pyr 3 (5), GSK5503A (8), CM4620 (14) and RO2959 (7). These represent the most promising candidates for future development of SOCE inhibitors for therapeutic use.

Independent endothelial functions of PIEZO1 and TRPV4 in hepatic portal vein and predominance of PIEZO1 in mechanical and osmotic stress

BACKGROUND & AIMS

PIEZO1 and TRPV4 are mechanically and osmotically regulated calcium-permeable channels. The aim of this study was to determine the relevance and relationship of these channels in the contractile tone of the hepatic portal vein, which experiences mechanical and osmotic variations as it delivers blood to the liver from the intestines, gallbladder, pancreas and spleen.

METHODS

Wall tension was measured in freshly dissected portal veins from adult male mice, which were genetically unmodified or modified for either a non-disruptive tag in native PIEZO1 or endothelial-specific PIEZO1 deletion. Pharmacological agents were used to activate or inhibit PIEZO1, TRPV4 and associated pathways, including Yoda1 and Yoda2 for PIEZO1 and GSK1016790A for TRPV4 agonism, respectively.

RESULTS

PIEZO1 activation leads to nitric oxide synthase- and endothelium-dependent relaxation of the portal vein. TRPV4 activation causes contraction, which is also endothelium-dependent but independent of nitric oxide synthase. The TRPV4-mediated contraction is suppressed by inhibitors of phospholipase A2 and cyclooxygenases and mimicked by prostaglandin E2 , suggesting mediation by arachidonic acid metabolism. TRPV4 antagonism inhibits the effect of agonising TRPV4 but not PIEZO1. Increased wall stretch and hypo-osmolality inhibit TRPV4 responses while lacking effects on or amplifying PIEZO1 responses.

CONCLUSIONS

The portal vein contains independently functioning PIEZO1 channels and TRPV4 channels in the endothelium, the pharmacological activation of which leads to opposing effects of vessel relaxation (PIEZO1) and contraction (TRPV4). In mechanical and osmotic strain, the PIEZO1 mechanism dominates. Modulators of these channels could present important new opportunities for manipulating liver perfusion and regeneration in disease and surgical procedures.

Improved PIEZO1 agonism through 4-benzoic acid modification of Yoda1

BACKGROUND AND PURPOSE

The protein PIEZO1 forms mechanically activated, calcium-permeable, non-selective cation channels in numerous cell types from several species. Options for pharmacological modulation are limited and so we modified a small-molecule agonist at PIEZO1 channels (Yoda1) to increase the ability to modulate these channels.

EXPERIMENTAL APPROACH

Medicinal chemistry generated Yoda1 analogues that were tested in intracellular calcium and patch-clamp assays on cultured cells exogenously expressing human or mouse PIEZO1 or mouse PIEZO2. Physicochemical assays and wire myography assays on veins from mice with genetic disruption of PIEZO1.

KEY RESULTS

A Yoda1 analogue (KC159) containing 4-benzoic acid instead of the pyrazine of Yoda1 and its potassium salt (KC289) have equivalent or improved reliability, efficacy and potency, compared with Yoda1 in functional assays. Tested against overexpressed mouse PIEZO1 in calcium assays, the order of potency (as EC50 values, nM) was KC289, 150 > KC159 280 > Yoda1, 600). These compounds were selective for PIEZO1 over other membrane proteins, and the physicochemical properties were more suited to physiological conditions than those of Yoda1. The vasorelaxant effects were consistent with PIEZO1 agonism. In contrast, substitution with 2-benzoic acid failed to generate a modulator.

CONCLUSION AND IMPLICATIONS

4-Benzoic acid modification of Yoda1 improves PIEZO1 agonist activity at PIEZO1 channels. We suggest naming this new modulator Yoda2. It should be a useful tool compound in physiological assays and facilitate efforts to identify a binding site. Such compounds may have therapeutic potential, for example, in diseases linked genetically to PIEZO1 such as lymphatic dysplasia.

Nusinersen Treatment of Children with Later-Onset Spinal Muscular Atrophy and Scoliosis Is Associated with Improvements or Stabilization of Motor Function

Nusinersen has been shown to improve or stabilize motor function in individuals with spinal muscular atrophy (SMA). We evaluated baseline scoliosis severity and motor function in nusinersen-treated non-ambulatory children with later-onset SMA. Post hoc analyses were conducted on 95 children initiating nusinersen treatment in the CHERISH study or SHINE long-term extension trial. Participants were categorized by baseline Cobb angle (first nusinersen dose): ≤10°, >10° to ≤20°, and >20° to <40° (no/mild/moderate scoliosis, respectively). Outcome measures included the Hammersmith Functional Motor Score-Expanded (HFMSE) and the Revised Upper Limb Module (RULM). Regression analysis determined the relationships between baseline scoliosis severity and later motor function. For children with no, mild, and moderate scoliosis, the mean increase in HFMSE from baseline to Day 930 was 6.0, 3.9, and 0.7 points, and in RULM was 6.1, 4.6, and 2.3 points. In the linear model, a 10° increase in baseline Cobb angle was significantly associated with a -1.4 (95% CI -2.6, -0.2) point decrease in HFMSE (p = 0.02) and a -1.2 (95% CI -2.1, -0.4) point decrease in RULM (p = 0.006) at Day 930. Treatment with nusinersen was associated with improvements/stabilization in motor function in all groups, with greater response in those with no/mild scoliosis at baseline.

Continued benefit of nusinersen initiated in the presymptomatic stage of spinal muscular atrophy: 5-year update of the NURTURE study

INTRODUCTION/AIMS

NURTURE (NCT02386553) is an open-label study of nusinersen in children (two SMN2 copies, n = 15; three SMN2 copies, n = 10) who initiated treatment in the presymptomatic stage of spinal muscular atrophy (SMA). A prior analysis after ~3 y showed benefits on survival, respiratory outcomes, motor milestone achievement, and a favorable safety profile. An additional 2 y of follow-up (data cut: February 15, 2021) are reported.

METHODS

The primary endpoint is time to death or respiratory intervention (≥6 h/day continuously for ≥7 days or tracheostomy). Secondary outcomes include overall survival, motor function, and safety.

RESULTS

Median age of children was 4.9 (3.8-5.5) y at last visit. No children have discontinued the study or treatment. All were alive. No additional children utilized respiratory intervention (defined per primary endpoint) since the prior data cut. Children with three SMN2 copies achieved all World Health Organization (WHO) motor milestones, with all but one milestone in one child within normal developmental timeframes. All 15 children with two SMN2 copies achieved sitting without support, 14/15 walking with assistance, and 13/15 walking alone. Mean Hammersmith Functional Motor Scale Expanded total scores showed continued improvement. Subgroups with two SMN2 copies, minimum baseline compound muscle action potential amplitude ≥2 mV, and no baseline areflexia had better motor and nonmotor outcomes versus all children with two SMN2 copies.

DISCUSSION

These results demonstrate the value of early treatment, durability of treatment effect, and favorable safety profile after ~5 y of nusinersen treatment. Inclusion/exclusion criteria and baseline characteristics should be considered when interpreting presymptomatic SMA trial data.

DEVOTE Study Exploring Higher Dose of Nusinersen in Spinal Muscular Atrophy: Study Design and Part A Results

BACKGROUND

Pharmacokinetic/pharmacodynamic modeling indicates that the higher dose of nusinersen may be associated with a clinically meaningful increase in efficacy above that seen with the 12-mg approved dose.

OBJECTIVE

Here we describe both the design of DEVOTE (NCT04089566), a 3-part clinical study evaluating safety, tolerability, and efficacy of higher dose of nusinersen, and results from the initial Part A.

METHODS

DEVOTE Part A evaluates safety and tolerability of a higher nusinersen dose; Part B assesses efficacy in a randomized, double-blind design; and Part C assesses safety and tolerability of participants transitioning from the 12-mg dose to higher doses.

RESULTS

In the completed Part A of DEVOTE, all 6 enrolled participants aged 6.1-12.6 years have completed the study. Four participants experienced treatment-emergent adverse events (TEAEs), the majority of which were mild. Common TEAEs of headache, pain, chills, vomiting, and paresthesia were considered related to the lumbar puncture procedure. There were no safety concerns regarding clinical or laboratory parameters. Nusinersen levels in the cerebrospinal fluid were within the range of modeled predictions for higher dose of nusinersen. While Part A was not designed for assessing efficacy, most participants showed stabilization or improvement in motor function. Parts B and C of DEVOTE are ongoing.

CONCLUSIONS

The findings from Part A of the DEVOTE study support further development of higher dose of nusinersen.

Glycated albumin modulates the contact system with implications for the kallikrein-kinin and intrinsic coagulation systems

BACKGROUND

Human serum albumin (HSA) is the most abundant plasma protein and is sensitive to glycation in vivo. The chronic hyperglycemic conditions in patients with diabetes mellitus (DM) induce a nonenzymatic Maillard reaction that denatures plasma proteins and forms advanced glycation end products (AGEs). HSA-AGE is a prevalent misfolded protein in patients with DM and is associated with factor XII activation and downstream proinflammatory kallikrein-kinin system activity without any associated procoagulant activity of the intrinsic pathway.

OBJECTIVES

This study aimed to determine the relevance of HSA-AGE toward diabetic pathophysiology.

METHODS

The plasma obtained from patients with DM and euglycemic volunteers was probed for activation of FXII, prekallikrein (PK), and cleaved high-molecular-weight kininogen by immunoblotting. Constitutive plasma kallikrein activity was determined via chromogenic assay. Activation and kinetic modulation of FXII, PK, FXI, FIX, and FX via in vitro-generated HSA-AGE were explored using chromogenic assays, plasma-clotting assays, and an in vitro flow model using whole blood.

RESULTS

Plasma obtained from patients with DM contained increased plasma AGEs, activated FXIIa, and resultant cleaved cleaved high-molecular-weight kininogen. Elevated constitutive plasma kallikrein enzymatic activity was identified, which positively correlated with glycated hemoglobin levels, representing the first evidence of this phenomenon. HSA-AGE, generated in vitro, triggered FXIIa-dependent PK activation but limited the intrinsic coagulation pathway activation by inhibiting FXIa and FIXa-dependent FX activation in plasma.

CONCLUSION

These data indicate a proinflammatory role of HSA-AGEs in the pathophysiology of DM via FXII and kallikrein-kinin system activation. A procoagulant effect of FXII activation was lost through the inhibition of FXIa and FIXa-dependent FX activation by HSA-AGEs.

Orai1 Inhibitors as Potential Treatments for Pulmonary Arterial Hypertension

BACKGROUND

Pulmonary arterial hypertension (PAH) is characterized by progressive distal pulmonary artery (PA) obstruction, leading to right ventricular hypertrophy and failure. Exacerbated intracellular calcium (Ca²⁺) signaling contributes to abnormalities in PA smooth muscle cells (PASMCs), including aberrant proliferation, apoptosis resistance, exacerbated migration, and arterial contractility. Store-operated Ca²⁺ entry is involved in Ca²⁺ homeostasis in PASMCs, but its properties in PAH are unclear.

METHODS

Using a combination of Ca²⁺ imaging, molecular biology, in vitro, ex vivo, and in vivo approaches, we investigated the roles of the Orai1 SOC channel in PA remodeling in PAH and determined the consequences of pharmacological Orai1 inhibition in vivo using experimental models of pulmonary hypertension (PH).

RESULTS

Store-operated Ca²⁺ entry and Orai1 mRNA and protein were increased in human PASMCs (hPASMCs) from patients with PAH (PAH-hPASMCs). We found that MEK1/2 (mitogen-activated protein kinase kinase 1/2), NFAT (nuclear factor of activated T cells), and NFκB (nuclear factor-kappa B) contribute to the upregulation of Orai1 expression in PAH-hPASMCs. Using small interfering RNA (siRNA) and Orai1 inhibitors, we found that Orai1 inhibition reduced store-operated Ca²⁺ entry, mitochondrial Ca²⁺ uptake, aberrant proliferation, apoptosis resistance, migration, and excessive calcineurin activity in PAH-hPASMCs. Orai1 inhibitors reduced agonist-evoked constriction in human PAs. In experimental rat models of PH evoked by chronic hypoxia, monocrotaline, or Sugen/hypoxia, administration of Orai1 inhibitors (N-{4-[3,5-bis(Trifluoromethyl)-1H-pyrazol-1-yl]phenyl}-4-methyl-1,2,3-thiadiazole-5-carboxamide [BTP2], 4-(2,5-dimethoxyphenyl)-N-[(pyridin-4-yl)methyl]aniline [JPIII], or 5J4) protected against PH.

CONCLUSIONS

In human PAH and experimental PH, Orai1 expression and activity are increased. Orai1 inhibition normalizes the PAH-hPASMCs phenotype and attenuates PH in rat models. These results suggest that Orai1 should be considered as a relevant therapeutic target for PAH.

Oncologic outcomes of primary retroperitoneal lymph node dissection (RPLND) for stage II seminoma: Indiana University experience

e17012

Background: Stage II seminoma is typically treated with radiotherapy or chemotherapy based on NCCN guidelines. Primary RPLND has demonstrated efficacy as first-line therapy for retroperitoneal (RP)-only disease. Our aim was to study recurrences of patients undergoing primary RPLND for Stage IIa or IIb seminoma to identify clinicopathologic factors affecting outcomes. Methods: Using our prospectively maintained database, we identified patients that had primary RPLND for seminoma from 2014-2021. All patients had at least 6 months of follow up. Patients were clinical stage IIa or IIb at the time of surgery and underwent open RPLND. We used Kaplan-Meier analysis for recurrence free survival (RFS) and compared clinicopathologic factors. Results: We identified 67 patients that underwent RPLND for RP only seminoma. Table shows the clinical characteristics of patients experiencing recurrences (median follow up - 22.4 months) and excludes 2 patients that had adjuvant chemotherapy. The 2-year RFS rate was 80.2%. Eleven patients (16.4%) experienced recurrences. Kaplan Meier analysis demonstrated improved survival in patients that had an RPLND after 12 months of surveillance (p = 0.02). Fifty-six patients were presumably cured with surgery alone at time of last follow-up. No patients died of testis cancer. One patient had a recurrence within the surgical field. Two patients had contralateral recurrences that may have been cured with bilateral RP template dissection. Seven patients that had a bilateral template dissection had disease on the contralateral side, of which 4 patients had visible nodes on pre-operative scans. In total, 9 out of 67 patients had disease on the contralateral side suggesting that bilateral RP template could confer higher cure rates. Recurrences were successfully treated with BEPx3 (9 pts), Redo RPLND then BEPx3 (1 pt), BEPx3 then High Dose chemotherapy (1 pt), and EPx4 (1 pt). Conclusions: Primary RPLND for low volume RP disease is effective with over 80% chance of surgical cure. Recurrences were cured almost exclusively with induction chemotherapy. Patients with delayed RP only recurrences had improved surgical success. Further investigation in larger trials may help standardize bilateral templates in seminoma and surveillance protocols in the post-operative setting. [Table: see text]

Scientific rationale for a higher dose of nusinersen

Objective

The long‐term favorable safety profile of nusinersen provides an opportunity to consider a higher dose. We report on the relationships between nusinersen cerebrospinal fluid (CSF) exposure, biomarker levels, and clinical efficacy.

Methods

The analyses used data from the CS3A and ENDEAR studies of nusinersen in participants with infantile‐onset spinal muscular atrophy (SMA). Steady‐state CSF trough (C_trough) levels, plasma phosphorylated neurofilament heavy chain (pNF‐H) levels, body weight, and Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND) scores were selected as parameters of interest. A validated population pharmacokinetic (PK) model was applied to predict the nusinersen CSF C_trough. PK/pharmacodynamic (PK/PD) models used nusinersen CSF C_trough measurements, which were time‐matched with CHOP INTEND scores.

Results

Higher nusinersen CSF exposure was associated with a greater decrease in pNF‐H levels and greater efficacy, as measured by change in the CHOP INTEND score from baseline. These findings indicate a dose–response relationship between CSF nusinersen levels and treatment response. The higher dose is predicted to lead to approximately a 2.4‐fold increase in nusinersen CSF levels with fewer loading doses. PK/PD modeling indicates that a higher concentration of nusinersen may predict an additional 5‐point increase in CHOP INTEND score beyond that observed with 12 mg.

Interpretation

Our data indicate that a higher dose of nusinersen may lead to additional clinically meaningful improvement in efficacy when compared with the currently approved 12‐mg dose. The efficacy, safety, and PK of a higher nusinersen dose are currently under investigation in the ongoing phase 2/3 DEVOTE study (NCT04089566).

Novel interaction of properdin and coagulation factor XI: Crosstalk between complement and coagulation

Background

Evidence of crosstalk between the complement and coagulation cascades exists, and dysregulation of either pathway can lead to serious thromboinflammatory events. Both the intrinsic pathway of coagulation and the alternative pathway of complement interact with anionic surfaces, such as glycosaminoglycans. Hitherto, there is no evidence for a direct interaction of properdin (factor P [FP]), the only known positive regulator of complement, with coagulation factor XI (FXI) or activated FXI (FXIa).

Objectives

The aim was to investigate crosstalk between FP and the intrinsic pathway and the potential downstream consequences.

Methods

Chromogenic assays were established to characterize autoactivation of FXI in the presence of dextran sulfate (DXS), enzyme kinetics of FXIa, and the downstream effects of FP on intrinsic pathway activity. Substrate specificity changes were investigated using SDS-PAGE and liquid chromatography-mass spectrometry (LC-MS). Surface plasmon resonance (SPR) was used to determine direct binding between FP and FXIa.

Results/Conclusions

We identified a novel interaction of FP with FXIa resulting in functional consequences. FP reduces activity of autoactivated FXIa toward S-2288. FXIa can cleave FP in the presence of DXS, demonstrated using SDS-PAGE, and confirmed by LC-MS. FXIa can cleave factor IX (FIX) and FP in the presence of DXS, determined by SDS-PAGE. DXS alone modulates FXIa activity, and this effect is further modulated by FP. We demonstrate that FXI and FXIa bind to FP with high affinity. Furthermore, FX activation downstream of FXIa cleavage of FIX is modulated by FP. These findings suggest a novel intercommunication between complement and coagulation pathways.

Tuning the rate of aggregation of hIAPP into amyloid using small-molecule modulators of assembly

Human islet amyloid polypeptide (hIAPP) self-assembles into amyloid fibrils which deposit in pancreatic islets of type 2 diabetes (T2D) patients. Here, we applied chemical kinetics to study the mechanism of amyloid assembly of wild-type hIAPP and its more amyloidogenic natural variant S20G. We show that the aggregation of both peptides involves primary nucleation, secondary nucleation and elongation. We also report the discovery of two structurally distinct small-molecule modulators of hIAPP assembly, one delaying the aggregation of wt hIAPP, but not S20G; while the other enhances the rate of aggregation of both variants at substoichiometric concentrations. Investigation into the inhibition mechanism(s) using chemical kinetics, native mass spectrometry, fluorescence titration, SPR and NMR revealed that the inhibitor retards primary nucleation, secondary nucleation and elongation, by binding peptide monomers. By contrast, the accelerator predominantly interacts with species formed in the lag phase. These compounds represent useful chemical tools to study hIAPP aggregation and may serve as promising starting-points for the development of therapeutics for T2D.

A Comparative Assessment Study of Known Small-molecule GPVI Modulators

The GPVI platelet receptor was recently validated as a safe antiplatelet target for the treatment of thrombosis using several peptidic modulators. In contrast, few weakly potent small-molecule GPVI antagonists have been reported. Those that have been published often lack evidence for target engagement, and their biological efficacy cannot be compared because of the natural donor variability associated with the assays implemented. Herein, we present the first side-by-side assessment of the reported GPVI small-molecule modulators. We have characterized their functional activities on platelet activation and aggregation using flow cytometry as well as light transmission and electrical impedance aggregometry. We also utilized microscale thermophoresis (MST) and saturation transfer difference (STD) NMR to validate GPVI binding and have used this along with molecular modeling to suggest potential binding interactions. We conclude that of the compounds examined, losartan and compound 5 are currently the most viable GPVI modulators.

Pathobiology, irradiation dosimetric parameters and therapy of radiation-induced gastric damage: a narrative review

OBJECTIVE

To review the pathobiology, irradiation dosimetric parameters and other risk factors, and therapy of radiation-induced gastric damage (RIGD).

BACKGROUND

RIGD is a side-effect of upper abdominal radiotherapy. Acute toxicities are usually mild and self-limiting. Late toxicities are potentially life-threatening and include bleeding, perforation or stenosis. The data on RIGD is mainly historical and derived from neoplasms and treatments where the role of radiotherapy is contracting, such as para-aortic nodal irradiation for testis and cervical cancer and Hodgkin's Disease. On the other hand, the role of radiotherapy is expanding, especially with stereotactic body radiotherapy (SBRT) treatments evolving for both primary and secondary upper gastrointestinal neoplasms, which might be expected to increase the frequency of RIGD. Pathoclinical and radiation dosimetric data which might predict the risk of RIGD are evaluated.

METHODS

English language articles between 1945 and December 2020, using PubMed and Embase, searching titles for keywords including: radiation; ionizing; radiotherapy; gastritis and 65 articles were selected for review. There may have been a risk of bias in the studies evaluated, since the majority of reports were retrospective, largely descriptive and qualitative.

CONCLUSIONS

A common pathoclinical theme in RIGD is inflammation. Numerous factors predict for a greater likelihood of RIGD, including radiation fraction size and dose, concurrent chemotherapy and previous abdominal surgery. Therapy is pathology-dependent and comprises pharmacological, interventional and in the most severe cases, surgical approaches. It is timely to review the topic of RIGD, discuss the limitations of the data and highlight the need for future research directions.

SARS-CoV-2 infects the human kidney and drives fibrosis in kidney organoids

Kidney failure is frequently observed during and after COVID-19, but it remains elusive whether this is a direct effect of the virus. Here, we report that SARS-CoV-2 directly infects kidney cells and is associated with increased tubule-interstitial kidney fibrosis in patient autopsy samples. To study direct effects of the virus on the kidney independent of systemic effects of COVID-19, we infected human-induced pluripotent stem-cell-derived kidney organoids with SARS-CoV-2. Single-cell RNA sequencing indicated injury and dedifferentiation of infected cells with activation of profibrotic signaling pathways. Importantly, SARS-CoV-2 infection also led to increased collagen 1 protein expression in organoids. A SARS-CoV-2 protease inhibitor was able to ameliorate the infection of kidney cells by SARS-CoV-2. Our results suggest that SARS-CoV-2 can directly infect kidney cells and induce cell injury with subsequent fibrosis. These data could explain both acute kidney injury in COVID-19 patients and the development of chronic kidney disease in long COVID.

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COVID-19 patients present tubulo-interstitial kidney fibrosis compared with controls

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SARS-CoV-2 infection stimulates profibrotic signaling in human kidney organoids

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SARS-CoV-2 infection can be inhibited by a protease blocker in human kidney organoids

Radiation recall reactions: An oncologic enigma

Radiation recall reactions (RRR) are uncommon but are a well-known phenomenon to oncologists. Tissue damage in a prior irradiation portal is 'recalled' after the administration of a drug, historically cytotoxics, or more recently, targeted or immunotherapeutic agents. Even COVID-19 vaccines are a reported cause. RRR are enigmatic in that their cause is unknown, but they generally have the histopathological and clinical features of acute or chronic inflammation. They can occur in a variety of tissues, the commonest being skin, which accounts for two-thirds of reported cases. They are generally relatively mild and self-limiting once the trigger drug is stopped, although severe cases with tissue necrosis have occurred. Rechallenge with drug does not necessarily cause reactivation of the reaction. Symptomatic treatment with steroids and antihistamines are usually effective, but their impact on the clinical course is unclear. Various hypotheses have been proposed as to the mechanism of RRR; a non-immune fixed drug reaction-like condition, dysregulated release of reactive oxygen species, abnormalities of tissue vasculature and impaired DNA repair. All could lead to a characteristic inflammatory microenvironment, resulting in dysfunction of tissue stem cells, keratinocyte necrosis and dermal abnormalities. Alternatively or in addition, low levels of inflammatory tissue cytokines induced by previous irradiation might be further upregulated by drug exposure. Most information in this review refers to data derived from cutaneous RRR, since they are the most common form reported.

The SARS-CoV-2 Spike protein alters human cardiac pericyte function and interaction with endothelial cells through a non-infective mechanism involving activation of CD147 receptor signalling

Background

Human cardiac pericytes (PC) were proposed as the main cellular target for SARS-CoV-2 in the heart due to high transcriptional levels of the angiotensin-converting enzyme 2 (ACE2) receptor. Emerging reports indicate CD147/Basigin (BSG), highly expressed in endothelial cells (EC), is an alternative SARS-CoV-2 receptor. To date, the mechanism by which the virus infects and disrupts the heart vascular cells was not identified yet. Moreover, cleaved Spike (S) protein molecules could be released into the bloodstream from the leaking pulmonary epithelial-endothelial barrier in patients with severe COVID-19, opening to the possibility of non-infective diseases in organs distant from the primary site of infection.

Purposes

(1) to confirm that human primary cardiac PC express ACE2 and CD147; (2) to verify if PC are permissible to SARS-CoV-2 infection; (3) to investigate if the recombinant SARS-CoV-2 S protein alone, without the other viral elements, can trigger molecular signalling and induce functional alterations in PC; (4) to explore which viral receptor is responsible for the observed events.

Methods and results

Cardiac PC express both the ACE2 and CD147 receptors at mRNA and protein level. Incubation of PC for up to 5 days with SARS-CoV-2 expressing the green fluorescent protein (GFP) did not show any evidence of cell infection or viral replication. Next, we exposed the PC to the recombinant S protein (5.8 nM) and confirmed that the protein engaged with cellular receptors (western blot analysis of S protein in treated and control PC). Incubation with the S protein increased PC migration (wound closure assay, P&lt;0.01 vs ctrl) and reduced the formation of tubular structures between PC and EC in a Matrigel assay (P&lt;0.01 vs ctrl). Moreover, the S protein promoted the production of pro-inflammatory factors typical of the cytokine storm in PC (ELISA measurement of MCP1, IL-6, IL-1β, TNFα, P&lt;0.05 vs ctrl), and induced the secretion of pro-apoptotic factors responsible for EC death (Caspase 3/7 assay, P&lt;0.05 vs ctrl). Signalling studies revealed that the S protein triggers the phosphorylation/activation of the extracellular signal-regulated kinase 1/2 (ERK1/2) through the CD147 receptor, but not ACE2, in cardiac PC. The neutralization of CD147, using a blocking antibody, prevented ERK1/2 activation in PC, and was reflected into a partial rescue of the cell functional behaviour (migration and pro-angiogenic capacity). In contrast, blockage of CD147 failed to prevent the pro-inflammatory response in PC.

Conclusions

We propose the novel hypothesis that COVID-19 associated heart's microvascular dysfunction is prompted by circulating S protein molecules rather than by the direct coronavirus infection of PC. Besides, we propose CD147, and not ACE2, as the leading receptor mediating S protein signalling in cardiac PC.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): BHF project grant “Targeting the SARS-CoV-2 S-protein binding to the ACE2 receptor to preserve human cardiac pericytes function in COVID-19” BHF Centre for Vascular Regeneration II

Treatment of infantile-onset spinal muscular atrophy with nusinersen: final report of a phase 2, open-label, multicentre, dose-escalation study

BACKGROUND

Nusinersen showed a favourable benefit-risk profile in participants with infantile-onset spinal muscular atrophy at the interim analysis of a phase 2 clinical study. We present the study's final analysis, assessing the efficacy and safety of nusinersen over 3 years.

METHODS

This phase 2, open-label, multicentre, dose-escalation study was done in three university hospital sites in the USA and one in Canada. Infants aged between 3 weeks and 6 months with two or three SMN2 gene copies and infantile-onset spinal muscular atrophy were eligible for inclusion. Eligible participants received multiple intrathecal loading doses of 6 mg equivalent nusinersen (cohort 1) or 12 mg dose equivalent (cohort 2), followed by maintenance doses of 12 mg equivalent nusinersen. The protocol amendment on Jan 25, 2016, changed the primary efficacy endpoint from safety and tolerability to reaching motor milestones, assessed using the Hammersmith Infant Neurological Examination section 2 (HINE-2) at the last study visit, in all participants who successfully completed the loading dose period and day 92 assessment. The statistical analysis plan was amended on Feb 10, 2016, to include additional analyses of the subgroup of participants with two SMN2 copies. Adverse events were assessed in all participants who received at least one dose of study treatment. The study is registered at ClinicalTrials.gov (NCT01839656).

FINDINGS

Between May 3, 2013, and July 9, 2014, 20 symptomatic participants with infantile-onset spinal muscular atrophy (12 boys and 8 girls; median age at diagnosis 78 days [range 0-154]) were enrolled. Median time on study was 36·2 months (IQR 20·6-41·3). The primary endpoint of an incremental improvement in HINE-2 developmental motor milestones was reached by 12 (63%) of 19 evaluable participants. In the 13 participants with two SMN2 copies treated with 12 mg nusinersen, the HINE-2 motor milestone total score increased steadily from a baseline mean of 1·46 (SD 0·52) to 11·86 (6·18) at day 1135, representing a clinically significant change of 10·43 (6·05). At study closure (Aug 21, 2017), 15 (75%) of 20 participants were alive. 101 serious adverse events were reported in 16 (80%) of 20 participants; all five deaths (one in cohort 1 and four in cohort 2) were likely to be related to spinal muscular atrophy disease progression.

INTERPRETATION

Our findings are consistent with other trials of nusinersen and show improved survival and attainment of motor milestones over 3 years in patients with infantile-onset spinal muscular atrophy, with a favourable safety profile.

FUNDING

Biogen and Ionis Pharmaceuticals.

Late relapse of germ cell tumors: Detection and treatment outcomes

5007

Background: Late relapse (LR) of germ cell tumors (GCT) is defined as relapsed disease > 2 years from initial treatment. LR remains a challenge both for optimal screening methods and treatment. We report the method of detection, treatments received, and outcomes in patients with LR GCT. Methods: The prospectively maintained Indiana University testicular cancer database was queried identifying 2712 pts with GCT treated at Indiana University from January 2000 to January 2019. Method of detection of LR was recorded along with site, treatment received, chemo-naive vs chemo-exposed LR, and survival outcomes. Results: 90 pts with LR were identified. Median age at LR was 35.2 yr (range, 19.2-56.8). Primary tumor site was testis in 88 (98%), retroperitoneum in 1 (1%), and mediastinum in 1 (1%). Chemo-exposed accounted for 42 (47%) and chemo-naïve for 48 (53%) of cases. Table compares clinical characteristics and survival outcomes of chemo-exposed vs. chemo-naïve late relapse. 62% of chemo-exposed LR were diagnosed with elevated AFP. For the 42 chemo-exposed LR pts, 2-yr PFS based on treatment: surgery vs. chemo vs surgery+chemo was 48% vs 10% vs 45% (p = 0.105). For the 48 chemo-naïve LR pts, 2-yr PFS based on treatment: surgery vs. chemo vs. surgery+chemo was 100% vs 74% vs 37% (p = 0.004). Next generation sequencing was available for 9 patients. No actionable findings were found. Tumor mutational burden was low in all patients where genomic testing was available. Conclusions: Most pts with chemo-exposed LR will be diagnosed with an elevated AFP. GCT pts require lifetime follow-up with annual physical exam and tumor markers. Surgical resection, when feasible, remains our preferred treatment for chemo-exposed LR as chemotherapy alone offers only brief responses. Pts with chemo-naïve LR have more chemo-sensitive biology.[Table: see text]

Adjuvant chemotherapy with CAV/IE for malignant transformation of teratoma to primitive neuroectodermal tumor (PNET): An institutional analysis from Indiana University

5026

Background: Malignant transformation of teratoma to PNET has an aggressive disease biology and generally poor outcomes when metastasis occurs. The optimal management of patients (pts) with PNET who have complete surgical extirpation is unknown. Most pts who are monitored with surveillance will relapse. We report results from pts with metastatic PNET who had complete surgical resection to NED status followed by adjuvant chemotherapy, most commonly cyclophosphamide + doxorubicin + vincristine alternating with ifosfamide + etoposide (CAV/IE) for 4 cycles. Methods: We reviewed records for pts with histologically confirmed malignant transformation of teratoma at Indiana University from 1990 to 2020. We identified 13 pts with PNET who underwent resection of metastatic disease to NED status followed by treatment with adjuvant chemotherapy, most commonly CAV/IE comprising of cyclophosphamide (1200 mg/m2), doxorubicin (75 mg/m2), and vincristine (2 mg/m2) alternating with ifosfamide (1.8 g/m2) plus etoposide (100 mg/m2). Treatment was delivered every 3 weeks for 4 cycles or until unacceptable toxicity. Results: Thirteen pts with metastatic PNET resected to NED status and received adjuvant chemotherapy were identified. Median age at diagnosis was 29 (range, 20 to 55). Primary tumor site was testis in 11 pts, retroperitoneum in 1 pt, and mediastinum in 1 pt. Metastasis site was retroperitoneal lymph nodes in 11 pts, mediastinal lymph nodes in 1 pt, and local mediastinal recurrence in 1 pt. After resection to NED status, all 13 pts were treated with adjuvant chemotherapy: 11 pts were treated with CAV/IE and 2 received etoposide-ifosfamide-cisplatin (VIP) x 2. Among the 11 pts who received CAV/IE: 3 pts received < 4 cycles due to toxicity and 8 completed 4 cycles. With a median follow-up of 16.3 months, 3 of 13 pts relapsed (23%) and 10 of 13 remained continuously disease free (77%). Of those who relapsed, median time to relapse was 9.3 months, 2 remained alive with disease at follow up and one patient died of disease progression. Conclusions: Adjuvant CAV/IE improves the outcomes of pts with malignant transformation of teratoma to PNET and who had resection of metastasis to NED status. Most pts who received adjuvant therapy remain continuously disease-free in comparison to historically high relapse rates in pts with resected PNET monitored with surveillance.

Surveillance after complete response in patients with metastatic non-seminomatous germ-cell tumor (NSGCT)

5018

Background: The optimal management of patients (pts) with complete response (CR) after first-line chemotherapy remains unsettled with guidelines recommending either surveillance or retroperitoneal LN dissection (RPLND). We present long-term outcomes from a large dataset of pts managed with surveillance after achieving CR to first-line chemotherapy. Methods: The prospectively maintained Indiana University testicular cancer database was queried for pts with metastatic NSGCT treated between 1990-2017 who achieved a CR after first-line chemotherapy. CR was defined as normalization of tumor markers (AFP+hCG) and no residual mass > 1cm. Kaplan-Meier methods were used to analyze progression-free survival (PFS) and overall survival (OS). Results: 388 pts met eligibility and were included in this analysis. Median age at diagnosis was 28.4 (range, 13-61.5). Primary site was testis in 385 pts (99%). Primary tumor predominant histology was embryonal ca (241), mixed (61), seminoma (31), yolk sac tumor (20), choriocarcinoma (10), and teratoma (14). 126 pts (32.5%) had teratoma in the primary tumor. Metastasis sites were retroperitoneum (295), mediastinal LN (15), pulmonary (149), liver (15), bone (7), and brain (6). IGCCCG risk was good in 325, intermediate in 25, and poor in 32 pts. Pre-chemotherapy retroperitoneal LN size was available in 232 pts: < 3cm in 170 and ≥3cm in 62. Median pre-chemo AFP was 10.7 (1-31,000) and hCG was 16.5 (0-595,930). First-line chemo was BEPx3 in 274, BEPx4 in 30, other regimens in 82 pts. With a median follow-up of 3.9 yrs, 34 pts (8.8%) progressed. At most recent follow-up, 363 (93.6%) pts were alive with no evidence of disease and 10 pts (2.6%) died of their disease. The estimated 2-yr PFS was 90.1% (95% CI: 86.2-93%) and 2-yr OS was 97.8% (95% CI: 95.2-99%). The estimated 2-yr PFS by IGCCCG risk category was 90.4% for good vs 90.4% for intermediate vs 86.5% for poor risk (p = 0.23), and the estimated 2-yr OS was 98.6% for good vs 95.5% for intermediate vs 92.9% for poor risk disease respectively (p = 0.002). For the 34 pts who progressed on surveillance, 16 (4%) progressed in the retroperitoneum only. 3 pts had malignant transformation of teratoma to PNET, adenocarcinoma, or other elements. 11 of progressed pts were treated with surgery, 12 were treated with salvage chemo, and 11 were treated with surgery+chemo. At most recent follow up, 21 of progressed pts had NED, 10 had died of disease, and 3 were lost to follow up. Conclusions: Pts with metastatic NSGCT who achieve CR after first-line chemotherapy can be safely observed with surveillance. Most pts who relapse can be salvaged with surgery and/or chemotherapy.

ORAI1 Ca2+ Channel as a Therapeutic Target in Pathological Vascular Remodelling

In the adult, vascular smooth muscle cells (VSMC) are normally physiologically quiescent, arranged circumferentially in one or more layers within blood vessel walls. Remodelling of native VSMC to a proliferative state for vascular development, adaptation or repair is driven by platelet-derived growth factor (PDGF). A key effector downstream of PDGF receptors is store-operated calcium entry (SOCE) mediated through the plasma membrane calcium ion channel, ORAI1, which is activated by the endoplasmic reticulum (ER) calcium store sensor, stromal interaction molecule-1 (STIM1). This SOCE was shown to play fundamental roles in the pathological remodelling of VSMC. Exciting transgenic lineage-tracing studies have revealed that the contribution of the phenotypically-modulated VSMC in atherosclerotic plaque formation is more significant than previously appreciated, and growing evidence supports the relevance of ORAI1 signalling in this pathologic remodelling. ORAI1 has also emerged as an attractive potential therapeutic target as it is accessible to extracellular compound inhibition. This is further supported by the progression of several ORAI1 inhibitors into clinical trials. Here we discuss the current knowledge of ORAI1-mediated signalling in pathologic vascular remodelling, particularly in the settings of atherosclerotic cardiovascular diseases (CVDs) and neointimal hyperplasia, and the recent developments in our understanding of the mechanisms by which ORAI1 coordinates VSMC phenotypic remodelling, through the activation of key transcription factor, nuclear factor of activated T-cell (NFAT). In addition, we discuss advances in therapeutic strategies aimed at the ORAI1 target.

127 A Student Pilot For A Feasibility Study of the Theoretical 3S Trial (SPFT3S): Patient Questionnaire and Demographics

Introduction

There is conflicting evidence on the benefit of statins for primary prevention of cardiovascular disease (CVD) in non-diabetics over 75. Emerging evidence shows they may be ineffective, yet current guidance supports their use in those up to 85. The objectives of this study were to assess patients’ understanding of statins, willingness to participate in a theoretical randomised controlled trial (RCT), where they would be randomised to stop their statin and to compare the trial population with national data.

Methods

The survey took place in 8 GP practices with 4 students involved in questionnaire distribution. A patient search identified those over 75 and on a statin. Patients were excluded if they had a history of CVD or diabetes. 36 patients were identified and completed questionnaires, 5 were removed because they reported exclusion criteria. Demographic data was compared to the UK population from the 2011 census.

Results

Of 31 participants, 71% understood why they took statins, most were unconcerned about side effects and only 1 patient stopped statins due to the media. Opinions on the theoretical “stopping statins trial” were varied. 35% of people responded positively. 29% would not want to take part and 36% of people were unsure. Comparison of our trial population against the national population shows that 903,505 people would be eligible for a UK trial.

Conclusions

The purpose of this exercise was to see if patients would be willing to participate in a trial where 50% stopped taking their statin. Approximately a third said yes and only a third said no. As there are nearly a million people in this population, it suggests a fully funded, larger-scale feasibility study of this theoretical randomised control trial is warranted.

126 A Student Pilot for A Feasibility Study of the Theoretical 3S Trial (SPFT3S): GP and Ethics Committee Members Questionnaire

Introduction

Emerging research suggests that statin use for primary prevention in people without diabetes aged 75 and older has no benefit. This study aims to determine the feasibility of the theoretical Stop Statin Study (3S), a double-blind randomised controlled trial carried out in general practice, which would test this hypothesis. 50% of trial patients would stop taking statins for 5 years in an event driven study. The questionnaires aim to identify the attitudes of general practitioners (GPs) and ethics committee members (ECMs) regarding stopping statins for 5 years in patients aged 75 and older without diabetes or history of cardiovascular disease and their willingness to allow patients to participate in the 3S study.

Method

Questionnaires comprised of 6 questions were designed. 4 students distributed the questionnaire and it was completed by 19 GPs based at 8 practices in the North-East of England. 31 ECMs (12 expert and 19 lay) responded by email.

Results

95% of GPs who completed the survey would agree to their patients participating in the theoretical study with 47% of GPs indicating that their willingness to participate in the study is patient dependent. 95% of GPs would also consider stopping statins in this population group if sufficient research had been carried out or if the guidelines were changed. 42% of GPs have a negative attitude to prescribing statins in this population group. All the ECMs would approve the study, citing over-prescribing and polypharmacy as their reason.

Conclusions

The majority of GPs will participate in the theoretical 3S study, if their patients are willing to participate. There is already a negative perception amongst GPs towards the use of statins in elderly people without disease. The 3S study appears to be feasible from the GP and ethics perspective but would require a larger feasibility study.

Prediction model for brain metastasis (BM) in patients with metastatic germ-cell tumors (mGCT) accounting for size of pulmonary metastases

378

Background: BM is an independent adverse prognostic factor that can lead to treatment complications and failure in pts with mGCT. We aimed to establish an effective and practical BM prediction model accounting for size of pulmonary metastases. Methods: 2,291 consecutive pts with mGCT treated at Indiana University between January 1990 and September 2017 were identified. Pts were divided into 2 categories: BM present (N=154) and BM absent (N=2137). Kaplan-Meier methods were used to analyze progression free survival (PFS) and overall survival (OS). Logistic regression was used to determine a predictive model for whether BM was present. The data was separated 50/50 into training and validation datasets with equal numbers of events in each. Size of pulmonary metastases were calculated based on the sum of long axis diameter of pulmonary metastases for each patient and were divided into <3cm vs. ≥3cm. Results: Baseline characteristics for 2 groups are listed in the table below. 2-yr PFS and OS for pts with vs without BM: 17% vs 65% (p<0.001) and 62% vs 91% (p<0.001) respectively. Among the 154 pts with BM, 64 (42%) had radiation only (whole-brain radiotherapy or gamma knife), 22 (14%) had BM-surgery only, 14 (9%) had both radiation and BM-surgery. 54 pts (35%) did not receive local therapy for BM. A stepwise selection was used to determine the best model with p<0.15 as the entry and staying criteria. The model with the largest ROC AUC was used moving forward. The model was tested in the validation dataset. A model was generated including age at diagnosis≥40 (1 point), pre-chemotherapy hCG≥5000 (1 point), presence of bone metastases (1 point), choriocarcinoma predominant histology (2 points), and presence of pulmonary metastases size <3 cm (2 points) or ≥3 cm (3 points). Patients with 0 points had a 0.6% probability of having BM, 1 point → 1.4%, 2 points → 3.5%, 3 points → 8.2%, 4 points → 18.3%, 5 points → 36%, 6 points → 58%, 7 points → 78%, and 8 points → 90%. Conclusions: The prediction model developed in this study demonstrated discrimination capability of predicting BM occurrence in mGCT and can be used by clinicians to identify high-risk pts. [Table: see text]

Metalloaminopeptidases of the Protozoan Parasite Plasmodium falciparum as Targets for the Discovery of Novel Antimalarial Drugs

Malaria poses a significant threat to approximately half of the world's population with an annual death toll close to half a million. The emergence of resistance to front-line antimalarials in the most lethal human parasite species, Plasmodium falciparum (Pf), threatens progress made in malaria control. The prospect of losing the efficacy of antimalarial drugs is driving the search for small molecules with new modes of action. Asexual reproduction of the parasite is critically dependent on the recycling of amino acids through catabolism of hemoglobin (Hb), which makes metalloaminopeptidases (MAPs) attractive targets for the development of new drugs. The Pf genome encodes eight MAPs, some of which have been found to be essential for parasite survival. In this article, we discuss the biological structure and function of each MAP within the Pf genome, along with the drug discovery efforts that have been undertaken to identify novel antimalarial candidates of therapeutic value.

The G Protein Biased Small Molecule Apelin Agonist CMF-019 is Disease Modifying in Endothelial Cell Apoptosis In Vitro and Induces Vasodilatation Without Desensitisation In Vivo

Signaling through the apelin receptor is beneficial for a number of diseases including pulmonary arterial hypertension. The endogenous small peptides, apelin and elabela/toddler, are downregulated in pulmonary arterial hypertension but are not suitable for exogenous administration owing to a lack of bioavailability, proteolytic instability and susceptibility to renal clearance. CMF-019, a small molecule apelin agonist that displays strong bias towards G protein signaling over β-arrestin (∼400 fold), may be more suitable. This study demonstrates that in addition to being a positive inotrope, CMF-019 caused dose-dependent vasodilatation in vivo (50 nmol 4.16 ± 1.18 mmHg, **p < 0.01; 500 nmol 6.62 ± 1.85 mmHg, **p < 0.01), without receptor desensitization. Furthermore, CMF-019 rescues human pulmonary artery endothelial cells from apoptosis induced by tumor necrosis factor α and cycloheximide (5.66 ± 0.97%, **p < 0.01) by approximately 50% of that observable with rhVEGF (11.59 ± 1.85%, **p < 0.01), suggesting it has disease-modifying potential in vitro. CMF-019 displays remarkable bias at the apelin receptor for a small molecule and importantly recapitulates all aspects of the cardiovascular responses to the endogenous ligand, [Pyr¹]apelin-13, in vivo. Additionally, it is able to protect human pulmonary artery endothelial cells from apoptosis, suggesting that the beneficial effects observed with apelin agonists extend beyond hemodynamic alleviation and address disease etiology itself. These findings support CMF-019 as a G protein biased small molecule apelin agonist in vitro and in vivo that could form the basis for the design of novel therapeutic agents in chronic diseases, such as, pulmonary arterial hypertension.

Developing and testing a principle-based fidelity index for peer support in mental health services

PURPOSE

Evidence suggests that the distinctive relational qualities of peer support-compared to clinical-patient relationships-can be eroded in regulated healthcare environments. Measurement of fidelity in trials of peer support is lacking. This paper reports the development and testing of a fidelity index for one-to-one peer support in mental health services, designed to assess fidelity to principles that characterise the distinctiveness of peer support.

METHODS

A draft index was developed using expert panels of service user researchers and people doing peer support, informed by an evidence-based, peer support principles framework. Two rounds of testing took place in 24 mental health services providing peer support in a range of settings. Fidelity was assessed through interviews with peer workers, their supervisors and people receiving peer support. Responses were tested for spread and internal consistency, independently double rated for inter-rater reliability, with feedback from interviewees and service user researchers used to refine the index.

RESULTS

A fidelity index for one-to-one peer support in mental health services was produced with good psychometric properties. Fidelity is assessed in four principle-based domains; building trusting relationships based on shared lived experience; reciprocity and mutuality; leadership, choice and control; building strengths and making connections to community.

CONCLUSIONS

The index offers potential to improve the evidence base for peer support in mental health services, enabling future trials to assess fidelity of interventions to peer support principles, and service providers a means of ensuring that peer support retains its distinctive qualities as it is introduced into mental health services.

Surgical Management of Retrocrural Disease in Germ Cell Tumors: Outcomes and Evolution of Practice

INTRODUCTION

Residual retrocrural disease in testis cancer following chemotherapy is a surgical challenge. We sought to assess the outcomes and evolution with surgical management of residual retrocrural disease.

MATERIALS AND METHODS

We identified 2,788 testicular cancer patients from 1990 to 2010 who underwent retroperitoneal surgery for metastatic testicular cancer at our institution. Patients who also underwent postchemotherapy staged or concurrent retrocrural dissections were stratified for analysis. Surgical approach, clinical characteristics, additional procedures, complications and outcomes were evaluated.

RESULTS

Retrocrural dissection was performed in 211 patients. Histology of retrocrural disease demonstrated teratoma in 72%, necrosis in 15.2%, active germ cell cancer in 8.1% and malignant transformation in 2.4%. Our preferred surgical approach to the retrocrural space has evolved over time. Earlier approaches from 1990 to 1995 favored a single thoracoabdominal incision (17, 25%), midline transabdominal incision (22, 32.4%), or with a concurrent or staged thoracotomy (29, 42.6%). A transabdominal/transdiaphragmatic approach at the time of midline retroperitoneal lymph node dissection has been used more frequently in 55% of contemporary cases, decreasing the need for thoracotomies. Patients undergoing a transabdominal/transdiaphragmatic approach had fewer complications (p=0.006) and required fewer associated procedures (p=0.001) and a shorter length of stay (5 vs 6 days, p=0.184).

CONCLUSIONS

Metastatic testis cancer to the retrocrural space is surgically challenging however complete resection is needed to maintain an expected excellent oncologic outcome. Coordination between urological and thoracic surgeons for an individualized approach is important. We have found that a transabdominal/transdiaphragmatic approach where appropriate has resulted in fewer complications.

Rationally derived inhibitors of hepatitis C virus (HCV) p7 channel activity reveal prospect for bimodal antiviral therapy

Since the 1960s, a single class of agent has been licensed targeting virus-encoded ion channels, or 'viroporins', contrasting the success of channel blocking drugs in other areas of medicine. Although resistance arose to these prototypic adamantane inhibitors of the influenza A virus (IAV) M2 proton channel, a growing number of clinically and economically important viruses are now recognised to encode essential viroporins providing potential targets for modern drug discovery. We describe the first rationally designed viroporin inhibitor with a comprehensive structure-activity relationship (SAR). This step-change in understanding not only revealed a second biological function for the p7 viroporin from hepatitis C virus (HCV) during virus entry, but also enabled the synthesis of a labelled tool compound that retained biological activity. Hence, p7 inhibitors (p7i) represent a unique class of HCV antiviral targeting both the spread and establishment of infection, as well as a precedent for future viroporin-targeted drug discovery.

Follow-up of renal impairment results among attendees taking HIV Pre-Exposure Prophylaxis at a Sydney Sexual Health Clinic

Renal monitoring is recommended for Pre-Exposure Prophylaxis (PrEP) users. We aimed to explore follow-up and outcomes among PrEP users with renal impairment (defined as estimated glomerular filtration rate <65 mL/min/1.73 m²) attending Sydney Sexual Health Centre. Time to follow-up was analysed for impairment results over a 12-month period (January-December 2018); 48/2504 (1.9%) tests among 1700 attendees showed impairment. Follow-up occurred in 39/48 (81.3%) impairment results after a median of 42 days. PrEP was ceased in 3/6 cases of non-resolving/persisting impairment, with one case of subsequent human immunodeficiency virus infection. Maintaining engagement and follow-up of those with renal impairment are important aspects of PrEP service provision.

Can m6A-modified RNA be used as an Anti-Viral Target?

Kaposi’s sarcoma-associated herpesvirus (KSHV) is a DNA virus associated with several HIV-associated malignancies.

Like all herpesviruses, KSHV has a biphasic life cycle encompassing a latent state and lytic replication. The KSHV replication and transcription activator viral protein, encoded from open reading frame 50 (ORF50), is the key viral protein which drives the switch between the latent and lytic phases (Guito and Lukac, 2012). We have recently demonstrated that KSHV manipulates the host cell N6-methyl adenosine (m6A) RNA modification pathway to enhance viral gene expression. Specifically, we have shown that the KSHV ORF50 transcript is m6A methylated, allowing the recruitment of the m6A reader protein, Staphylococcal nuclease domain-containing protein 1 (SND-1), resulting in the stabilisation of the ORF50 transcript and efficient KSHV lytic replication (Baquero-Perez et al. 2019).

Further analysis of the m6A modified site with the ORF50 transcript has identified an RNA stem-loop, termed ORF50-1, which is a m6A-modified 43-mer, essential for SND-1 binding, thought to occur in a secondary structure/ sequence-dependent manner. Taking this into consideration, novel ligands have been assessed as effective anti-viral reagents. The importance of A versus m6A within the lytic phase of KSHV’s lifecycle will be investigated by combining in silicoscreening with biophysical techniques and cell based assays.

Progress toward a Glycoprotein VI Modulator for the Treatment of Thrombosis

Pathogenic thrombus formation accounts for the etiology of many serious conditions including myocardial infarction, stroke, deep vein thrombosis, and pulmonary embolism. Despite the development of numerous anticoagulants and antiplatelet agents, the mortality rate associated with these diseases remains high. In recent years, however, significant epidemiological evidence and clinical models have emerged to suggest that modulation of the glycoprotein VI (GPVI) platelet receptor could be harnessed as a novel antiplatelet strategy. As such, many peptidic agents have been described in the past decade, while more recent efforts have focused on the development of small molecule modulators. Herein the rationale for targeting GPVI is summarized and the published GPVI modulators are reviewed, with particular focus on small molecules. A qualitative pharmacophore hypothesis for small molecule ligands at GPVI is also presented.

Model to predict brain metastasis (BM) in patients with metastatic germ-cell tumors (mGCT)

5057

Background: BM is an independent adverse prognostic factor that can lead to treatment complications and failure in pts with mGCT. We aimed to establish an effective and practical model for prediction of BM in mGCT. Methods: 2,256 consecutive pts with mGCT treated at Indiana University between January 1990 and September 2017 were identified. Pts were divided into 2 categories: BM present (N = 144) and BM absent (N = 2112). Kaplan-Meier methods were used to analyze progression free survival (PFS) and overall survival (OS). Logistic regression was used to determine a predictive model for whether BM was present. The data was separated 50/50 into training and validation datasets with equal numbers of events in each. Results: Baseline characteristics for 2 groups are listed in Table. 2-yr PFS and OS for pts with vs without BM: 17% vs 66% (p < 0.001) and 62% vs 91% (p < 0.001) respectively. Among the 144 pts with BM, 64 (44%) had radiation only (whole-brain radiotherapy or gamma knife), 21 (15%) had BM-surgery only, 14 (10%) had both radiation and BM-surgery. 45 pts (31%) did not receive local therapy for BM. A stepwise selection was used to determine the best model with p < 0.15 as the entry and staying criteria. The model with the largest ROC AUC was used moving forward. The model was tested in the validation dataset. A model was generated including age at diagnosis≥40 (1 point), presence of pulmonary metastases (3 points), bone metastasis (1 point), pre-chemotherapy hCG≥5000 (1 point), and choriocarcinoma predominant histology (1 point). Patients with 0 points had a 0.4% probability of BM, 1 point: 1%, 2 points: 2.6%, 3 points: 7%, 4 points: 16%, 5 points: 32%, 6 points: 56%, and 7 points: 77%. Details regarding analysis in training and validation datasets will be presented. Conclusions: The prediction model developed in this study demonstrated discrimination capability of predicting BM occurrence and can be used by clinicians to identify high-risk pts. [Table: see text]

Abstract B24: Development of small-molecule RAS inhibitors using Affimer reagents

Ras proteins are small GTPases that are mutationally activated in around 30% of all human cancers. Oncogenic mutations in Ras trigger uncontrolled cellular differentiation and division through uninhibited Ras-GTP signaling. Despite major efforts in developing inhibitors, lack of treatments directly targeting Ras in cancer led to the current assumption that Ras is undruggable. A new approach, which involves use of biologics, has shown great potential for development of Ras inhibitors, as demonstrated by recent increase in the number of antibody mimetic reagents targeting Ras, including single domain antibodies, monobodies and DARPins. We have developed modulators of Ras activity using novel artificial binding proteins, termed Affimers. Affimers are small 91-amino-acid scaffold proteins that constrain one or two randomized nine amino acid loop regions for molecular recognition. Affimers isolated against KRas, the most commonly mutated Ras family member, displayed low nanomolar binding affinities, were shown to be effective at inhibiting nucleotide exchange and blocked interaction between Ras and its effector Raf. When expressed in mammalian cells, Affimers bound with endogenous Ras and inhibited Ras-mediated signaling. Site-directed mutagenesis of Affimer variable regions revealed three residues critical for binding and inhibition. X-ray crystal structure of Affimer in complex with KRas demonstrated that these residues bind into a hydrophobic pocket on Ras, previously described with small molecules. Currently, we are determining whether this interaction gives insight into new modes of therapeutic development using molecular docking in attempt to mimic the Affimer residues with small molecules. This project provides a unique opportunity to further our understanding of Ras biology through the development of reagents that modulate Ras activity. In addition, structural insights into mode of inhibition allow the modelling and design of small-molecule compounds, providing novel therapeutic strategies to slow Ras-addicted tumor growth.

Citation Format: Katarzyna Haza, Heather Martin, Christian Tiede, Kevin Tipping, Chi Trinh, Holly Foster, Rachel Trowbridge, Richard Foster, Thomas Edwards, Alexander Breeze, Michael McPherson, Darren Tomlinson. Development of small-molecule RAS inhibitors using Affimer reagents [abstract]. In: Proceedings of the AACR Special Conference on Targeting RAS-Driven Cancers; 2018 Dec 9-12; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(5_Suppl):Abstract nr B24.

The evolution and alignment of institutional shareholder engagement through the King and CRISA reports

Purpose

The purpose of this study is to provide a high-level review of the evolution of shareholder activism and institutional investor engagement in the corporate governance ecosystem in South Africa. Furthermore, it specifically seeks to explain the incorporation of such aspects into the various key codes and reports on corporate governance in South Africa since 1994.

Design/methodology/approach

Historical narrative and analysis.

Findings

This study highlights how shareholder activism and institutional investor engagement in the corporate governance ecosystem have been considered and addressed in South Africa since the publication of the First King Report in 1994. The progress that has been made specifically with regard to the introduction of a code for institutional investors is highlighted. The study ultimately acknowledges that this evolution is a continuing journey on the road to stakeholder inclusivity and engagement, and then concludes that the specific role and impact of institutional investors, particularly given some of the recent corporate governance failures, will require further consideration going forward. This should ensure the continued alignment of all stakeholders and assist in making the necessary improvements to the overarching governance framework and attendant culture.

Originality/value

This study is a part of a special issue that looks at the contribution of the King reports to governance globally.