Oral 8-aminoguanine against age-related retinal degeneration.

Visual decline in the elderly is often attributed to retinal aging, which predisposes the tissue to pathologies such as age-related macular degeneration. Currently, effective oral pharmacological interventions for retinal degeneration are limited. We present a novel oral intervention, 8-aminoguanine (8-AG), targeting age-related retinal degeneration, utilizing the aged Fischer 344 rat model. A low-dose 8-AG regimen (5 mg/kg body weight) via drinking water, beginning at 22 months for 8 weeks, demonstrated significant retinal preservation. This was evidenced by increased retinal thickness, improved photoreceptor integrity, and enhanced electroretinogram responses. 8-AG effectively reduced apoptosis, oxidative damage, and microglial/macrophage activation associated with aging retinae. Age-induced alterations in the retinal purine metabolome, characterized by elevated levels of inosine, hypoxanthine, and xanthine, were partially mitigated by 8-AG. Transcriptomics highlighted 8-AG's anti-inflammatory effects on innate and adaptive immune responses. Extended treatment to 17 weeks further amplified the retinal protective effects. Moreover, 8-AG showed temporary protective effects in the RhoP23H/+ mouse model of retinitis pigmentosa, reducing active microglia/macrophages. Our study positions 8-AG as a promising oral agent against retinal aging. Coupled with previous findings in diverse disease models, 8-AG emerges as a promising anti-aging compound with the capability to reverse common aging hallmarks.

Exploring the Perspectives of Parents of Individuals with Autism from Low-Resourced Communities to Inform Family Navigator Programs.

Family navigator programs (i.e., programs to train family navigators) are becoming increasingly common among families of children with autism. Family navigators (i.e., individuals who help families access evaluations and/or services) may be parents of children with autism themselves or health professionals. Extant research has shown that family navigators can help families receive timely diagnostic evaluations and initial services. Yet, the development of family navigator programs is unclear; by exploring the input of families of children with autism, such programs can be responsive to family needs. In this study, we extend the extent literature by exploring the lived experiences of 12 parents of autistic children from low-resourced communities to inform the development of a family navigator program. Findings demonstrated that navigator programs need to prepare navigators to address barriers such as limited knowledge and difficulty accepting an autism diagnosis. Navigator programs should teach navigators to use strategies with families including educating families about services and connecting families with peer support. Program content should reflect direct services, government services, and advocacy strategies. Notably, for true improvements to service access for all autistic children, systemic changes are also needed in the service delivery systems. Implications are discussed.

How comparable are patient outcomes in the "real-world" with populations studied in pivotal AML trials?

Despite an increasing desire to use historical cohorts as "synthetic" controls for new drug evaluation, limited data exist regarding the comparability of real-world outcomes to those in clinical trials. Governmental cancer data often lacks details on treatment, response, and molecular characterization of disease sub-groups. The Australasian Leukaemia and Lymphoma Group National Blood Cancer Registry (ALLG NBCR) includes source information on morphology, cytogenetics, flow cytometry, and molecular features linked to treatment received (including transplantation), response to treatment, relapse, and survival outcome. Using data from 942 AML patients enrolled between 2012-2018, we assessed age and disease-matched control and interventional populations from published randomized trials that led to the registration of midostaurin, gemtuzumab ozogamicin, CPX-351, oral azacitidine, and venetoclax. Our analyses highlight important differences in real-world outcomes compared to clinical trial populations, including variations in anthracycline type, cytarabine intensity and scheduling during consolidation, and the frequency of allogeneic hematopoietic cell transplantation in first remission. Although real-world outcomes were comparable to some published studies, notable differences were apparent in others. If historical datasets were used to assess the impact of novel therapies, this work underscores the need to assess diverse datasets to enable geographic differences in treatment outcomes to be accounted for.

Quantification of Aging-Related Decreases in Sensory Innervation of the Bladder Trigone in Rats.

PURPOSE: The prevalence of lower urinary tract symptoms (LUTS), characterized by problems regarding storage and/or voiding of urine, is known to significantly increase with age. Effective communication between the lower urinary tract and the central nervous system (CNS) is essential for the optimal function of this system, and heavily relies on the efficient interaction between the bladder urothelium and the afferent nerve fibers situated in close proximity to the urothelium within the lamina propria. METHODS: We aimed to quantify aging-related differences in the expression of calcitonin gene-related peptide (CGRP, an established marker for sensory nerve fibers) in the trigonal mucosal layers of young (3-4 months) and aged (25-30 months) rats. We evaluated trigonal tissue from 3 animals per age group. Tissue was serially sectioned at 10 µm and stained for CGRP. Images were taken along the full length of the tissue. For each image we computed the total CGRP-positive area (µm2) and the median value for each animal was used for further analysis. RESULTS: Upon statistical analysis the aged rats show a significantly lower CGRP-positive area compared to young rats (P=0.0049). These results indicate that aging has a negative effect on the area of CGRP-positive signal in the trigone. CONCLUSION: The structural and functional integrity of the sensory web in the trigonum of rats is negatively affected by the aging process, potentially leading to impaired communication between the bladder urothelium the CNS. Consequently, these perturbations in the sensory system may contribute to the pathogenesis or exacerbation LUTS.

Pegargiminase Plus First-Line Chemotherapy in Patients With Nonepithelioid Pleural Mesothelioma: The ATOMIC-Meso Randomized Clinical Trial.

Importance: Arginine deprivation using ADI-PEG20 (pegargiminase) combined with chemotherapy is untested in a randomized study among patients with cancer. ATOMIC-Meso (ADI-PEG20 Targeting of Malignancies Induces Cytotoxicity-Mesothelioma) is a pivotal trial comparing standard first-line chemotherapy plus pegargiminase or placebo in patients with nonepithelioid pleural mesothelioma. Objective: To determine the effect of pegargiminase-based chemotherapy on survival in nonepithelioid pleural mesothelioma, an arginine-auxotrophic tumor. Design, Setting, and Participants: This was a phase 2-3, double-blind randomized clinical trial conducted at 43 centers in 5 countries that included patients with chemotherapy-naive nonepithelioid pleural mesothelioma from August 1, 2017, to August 15, 2021, with at least 12 months' follow-up. Final follow-up was on August 15, 2022. Data analysis was performed from March 2018 to June 2023. Intervention: Patients were randomly assigned (1:1) to receive weekly intramuscular pegargiminase (36.8 mg/m2) or placebo. All patients received intravenous pemetrexed (500 mg/m2) and platinum (75-mg/m2 cisplatin or carboplatin area under the curve 5) chemotherapy every 3 weeks up to 6 cycles. Pegargiminase or placebo was continued until progression, toxicity, or 24 months. Main Outcomes and Measures: The primary end point was overall survival, and secondary end points were progression-free survival and safety. Response rate by blinded independent central review was assessed in the phase 2 portion only. Results: Among 249 randomized patients (mean [SD] age, 69.5 [7.9] years; 43 female individuals [17.3%] and 206 male individuals [82.7%]), all were included in the analysis. The median overall survival was 9.3 months (95% CI, 7.9-11.8 months) with pegargiminase-chemotherapy as compared with 7.7 months (95% CI, 6.1-9.5 months) with placebo-chemotherapy (hazard ratio [HR] for death, 0.71; 95% CI, 0.55-0.93; P = .02). The median progression-free survival was 6.2 months (95% CI, 5.8-7.4 months) with pegargiminase-chemotherapy as compared with 5.6 months (95% CI, 4.1-5.9 months) with placebo-chemotherapy (HR, 0.65; 95% CI, 0.46-0.90; P = .02). Grade 3 to 4 adverse events with pegargiminase occurred in 36 patients (28.8%) and with placebo in 21 patients (16.9%); drug hypersensitivity and skin reactions occurred in the experimental arm in 3 patients (2.4%) and 2 patients (1.6%), respectively, and none in the placebo arm. Rates of poststudy treatments were comparable in both arms (57 patients [45.6%] with pegargiminase vs 58 patients [46.8%] with placebo). Conclusions and Relevance: In this randomized clinical trial of arginine depletion with pegargiminase plus chemotherapy, survival was extended beyond standard chemotherapy with a favorable safety profile in patients with nonepithelioid pleural mesothelioma. Pegargiminase-based chemotherapy as a novel antimetabolite strategy for mesothelioma validates wider clinical testing in oncology. Trial Registration: ClinicalTrials.gov Identifier: NCT02709512.

Purine nucleoside phosphorylase inhibition is an effective approach for the treatment of chemical hemorrhagic cystitis.

Hemorrhagic cystitis may be induced by infection, radiation therapy, or medications or may be idiopathic. Along with hemorrhagic features, symptoms include urinary urgency and frequency, dysuria (painful urination), and visceral pain. Cystitis-induced visceral pain is one of the most challenging types of pain to treat, and an effective treatment would address a major unmet medical need. We assessed the efficacy of a purine nucleoside phosphorylase inhibitor, 8-aminoguanine (8-AG), for the treatment of hemorrhagic/ulcerative cystitis. Lower urinary tract (LUT) function and structure were assessed in adult Sprague-Dawley rats, treated chronically with cyclophosphamide (CYP; sacrificed day 8) and randomized to daily oral treatment with 8-AG (begun 14 days prior to CYP induction) or its vehicle. CYP-treated rats exhibited multiple abnormalities, including increased urinary frequency and neural mechanosensitivity, reduced bladder levels of inosine, urothelial inflammation/damage, and activation of spinal cord microglia, which is associated with pain hypersensitivity. 8-AG treatment of CYP-treated rats normalized all observed histological, structural, biochemical, and physiological abnormalities. In cystitis 8-AG improved function and reduced both pain and inflammation likely by increasing inosine, a tissue-protective purine metabolite. These findings demonstrate that 8-AG has translational potential for reducing pain and preventing bladder damage in cystitis-associated LUT dysfunctions.

Hypoxanthine Induces Signs of Bladder Aging with Voiding dysfunction and Lower Urinary Tract Remodeling.

BACKGROUND: Lower urinary tract syndrome (LUTS) is a group of urinary tract symptoms and signs which can include urinary incontinence. Advancing age is a major risk factors for LUTS; however the underlying biochemical mechanisms of age-related LUTS remain unknown. HX (hypoxanthine) is a purine metabolite associated with generation of tissue damaging reactive oxygen species (ROS). This study tested the hypothesis that exposure of the adult bladder to HX-ROS over time damages key LUT elements, mimicking qualitatively some of the changes observed with aging. METHODS: Adult 3-month-old female Fischer 344 (F344) rats were treated with vehicle or HX (10 mg/kg/day; 3 weeks) administered in drinking water. Targeted purine metabolomics and molecular approaches were used to assess purine metabolites and biomarkers for oxidative stress and cellular damage. Biomechanical approaches assessed LUT structure and measurements of LUT function (using custom-metabolic cages and cystometry) were also employed. RESULTS: HX exposure increased biomarkers indicative of oxidative stress, pathophysiological ROS production and depletion of cellular energy with declines in NAD + levels. Moreover, HX treatment caused bladder remodeling and decreased the intercontraction interval and leak point pressure (surrogate measure to assess stress urinary incontinence). CONCLUSIONS: These studies provide evidence that in adult rats chronic exposure to HX causes changes in voiding behavior and in bladder structure resembling alterations observed with aging. These results suggest that increased levels of uro-damaging HX were associated with ROS/oxidative stress-associated cellular damage which may be central to age-associated development of LUTS, opening up potential opportunities for geroscience-guided interventions.

Proactive Recruitment Strategy for Patient Identification for Lung Cancer Screening.

PURPOSE: We assessed low-dose computed tomography (LDCT) screening for lung cancer using a proactive patient education/recruitment program. METHODS: We identified patients aged 55-80 years from a family medicine group. In the retrospective phase (March-August, 2019), patients were categorized as current/former/never smokers, and screening eligibility was determined. Patients who underwent LDCT in the past year, along with outcomes, were documented. In the prospective phase (2020), patients in the same cohort who did not undergo LDCT were proactively contacted by a nurse navigator to discuss eligibility and prescreening. Eligible and willing patients were referred to their primary care physician. RESULTS: In the retrospective phase, of 451 current/former smokers, 184 (40.8%) were eligible for LDCT, 104 (23.1%) were ineligible, and 163 (36.1%) had an incomplete smoking history. Of those eligible, 34 (18.5%) had LDCT ordered. In the prospective phase, 189 (41.9%) were eligible for LDCT (150 [79.4%] of whom had no prior LDCT or diagnostic CT), 106 (23.5%) were ineligible, and 156 (34.6%) had an incomplete smoking history. The nurse navigator identified an additional 56/451 (12.4%) patients as eligible after contacting patients with incomplete smoking history. In total, 206 patients (45.7%) were eligible, an increase of 37.3% compared with the retrospective phase (150). Of these, 122 (59.2%) verbally agreed to screening, 94 (45.6%) met with their physician, and 42 (20.4%) were prescribed LDCT. CONCLUSIONS: A proactive education/recruitment model increased eligible patients for LDCT by 37.3%. Proactive identification/education of patients desiring to pursue LDCT was 59.2%. It is essential to identify strategies that will increase and deliver LDCT screening among eligible and willing patients.

Aging-Associated Changes in Oxidative Stress Negatively Impacts the Urinary Bladder Urothelium.

PURPOSE: Lower urinary tract symptoms are known to significantly increase with age, negatively impacting quality of life and self-reliance. The urothelium fulfills crucial tasks, serving as a barrier protecting the underlying bladder tissue from the harsh chemical composition of urine, and exhibits signaling properties via the release of mediators within the bladder wall that affect bladder functioning. Aging is associated with detrimental changes in cellular health, in part by increasing oxidative stress in the bladder mucosa, and more specifically the urothelium. This, in turn, may impact urothelial mitochondrial health and bioenergetics. METHODS: We collected mucosal tissue samples from both young (3-4 months old) and aged (25-30 months old) rats. Tissue was evaluated for p21-Arc, nitrotyrosine, and cytochrome C expression by western immunoblotting. Urothelial cells were cultured for single-cell imaging to analyze basal levels of reactive oxygen species and the mitochondrial membrane potential. Mitochondrial bioenergetics and cellular respiration were investigated by the Seahorse assay, and measurements of adenosine triphosphate release were made using the luciferin-luciferase assay. RESULTS: Aging was associated with a significant increase in biomarkers of cellular senescence, oxidative stress, and basal levels of reactive oxygen species. The mitochondrial membrane potential was significantly lower in urothelial cell cultures from aged animals, and cultures from aged animals showed a significant decrease in mitochondrial bioenergetics. CONCLUSION: Aging-related increases in oxidative stress and excessive reactive oxygen species may be contributing factors underlying lower urinary tract symptoms in older adults. The mechanisms outlined in this study could be utilized to identify novel pharmaceutical targets to improve aging-associated bladder dysfunction.

Effects of vasopressin receptor agonists on detrusor smooth muscle tone in young and aged bladders: Implications for nocturia treatment.

Purpose: The main goal of this study was to determine the effects of arginine vasopressin (AVP) and desmopressin on bladder contractility and to examine whether the effects of these vasopressin receptor (VR) agonists differ in young versus aged animals. These aims were addressed using urinary bladders from young (3 months) and aged (24 month) female Fischer 344 rats that were isolated and dissected into strips for isometric tension recordings. Bladder strips were exposed to AVP and desmopressin through the perfusate, and tension changes recorded. Results: In young rat bladders, AVP, an agonist at both vasopressin-1 receptors (V1Rs) and vasopressin-2 receptor (V2Rs), concentration-dependently caused contraction of bladder strips with a sensitivity that was greater in young versus aged bladder strips. Removal of the mucosa did not alter the sensitivity of young bladder strips to AVP yet enhanced the AVP sensitivity of aged bladder strips. The differential sensitivity to AVP between young denuded and aged denuded bladder strips was similar. In contrast to AVP, desmopressin (V2R selective agonist) relaxed bladder strips. This response was reduced by removal of the mucosa in young, but not aged, bladder strips. Conclusion: These findings support a direct role for VRs in regulating detrusor tone with V1Rs causing contraction and V2Rs relaxation. In aged bladders, the contractile response to V1R activation is attenuated due to release of a mucosal factor that attenuates V1R-induced contractions. Also in aged bladders, the relaxation response to V2R activation is attenuated by lack of release of a mucosal factor that contributes to V2R-induced relaxation. Thus age-associated changes in the bladder mucosa impair the effects of VRs on bladder tone. Because the V2R signaling system is impaired in the older bladder, administering an exogenous V2R agonist (e.g., desmopressin) could counteract this defect. Thus, desmopressin could potentially increase nighttime bladder capacity through detrusor relaxation in concert with decreased urine production, reducing nocturnal voiding frequency.

Pilot Trial of Arginine Deprivation Plus Nivolumab and Ipilimumab in Patients with Metastatic Uveal Melanoma.

Metastatic uveal melanoma (UM) remains challenging to treat, with objective response rates to immune checkpoint blockade (ICB) being much lower than in primary cutaneous melanoma (CM). Besides a lower mutational burden, the overall immune-excluded tumor microenvironment of UM might contribute to the poor response rate. We therefore aimed at targeting deficiency in argininosuccinate synthase 1, which is a key metabolic feature of UM. This study aims at investigating the safety and tolerability of a triple combination consisting of ipilimumab and nivolumab immunotherapy and the metabolic therapy, ADI-PEG 20. Nine patients were enrolled in this pilot study. The combination therapy was safe and tolerable with an absence of immune-related adverse events (irAE) of special interest, but with four of nine patients experiencing a CTCAE grade 3 AE. No objective responses were observed. All except one patient developed anti-drug antibodies (ADA) within a month of the treatment initiation and therefore did not maintain arginine depletion. Further, an IFNg-dependent inflammatory signature was observed in metastatic lesions in patients pre-treated with ICB compared with patients with no pretreatment. Multiplex immunohistochemistry demonstrated variable presence of tumor infiltrating CD8 lymphocytes and PD-L1 expression at the baseline in metastases.

Aberrant neural activity in prefrontal pyramidal neurons lacking TDP-43 precedes neuron loss.

Mislocalization of TAR DNA binding protein 43 kDa (TARDBP, or TDP-43) is a principal pathological hallmark identified in cases of neurodegenerative disorders such as amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). As an RNA binding protein, TDP-43 serves in the nuclear compartment to repress non-conserved cryptic exons to ensure the normal transcriptome. Multiple lines of evidence from animal models and human studies support the view that loss of TDP-43 leads to neuron loss, independent of its cytosolic aggregation. However, the underlying pathogenic pathways driven by the loss-of-function mechanism are still poorly defined. We employed a genetic approach to determine the impact of TDP-43 loss in pyramidal neurons of the prefrontal cortex (PFC). Using a custom-built miniscope imaging system, we performed repetitive in vivo calcium imaging from freely behaving mice for up to 7 months. By comparing calcium activity in PFC pyramidal neurons between TDP-43 depleted and TDP-43 intact mice, we demonstrated remarkably increased numbers of pyramidal neurons exhibiting hyperactive calcium activity after short-term TDP-43 depletion, followed by rapid activity declines prior to neuron loss. Our results suggest aberrant neural activity driven by loss of TDP-43 as the pathogenic pathway at early stage in ALS and FTD.

A Phase 1 study of ADI-PEG20 (pegargiminase) combined with cisplatin and pemetrexed in ASS1-negative metastatic uveal melanoma.

Metastatic uveal melanoma (UM) is a devastating disease with few treatment options. We evaluated the safety, tolerability and preliminary activity of arginine depletion using pegylated arginine deiminase (ADI-PEG20; pegargiminase) combined with pemetrexed (Pem) and cisplatin (Cis) chemotherapy in a phase 1 dose-expansion study of patients with argininosuccinate synthetase (ASS1)-deficient metastatic UM. Eligible patients received up to six cycles of Pem (500 mg/m2 ) and Cis (75 mg/m2 ) every 3 weeks plus weekly intramuscular ADI (36 mg/m2 ), followed by maintenance ADI until progression (NCT02029690). Ten of fourteen ASS1-deficient patients with UM liver metastases and a median of one line of prior immunotherapy received ADIPemCis. Only one ≥ grade 3 adverse event of febrile neutropenia was reported. Seven patients had stable disease with a median progression-free survival of 3.0 months (range, 1.3-8.1) and a median overall survival of 11.5 months (range, 3.2-36.9). Despite anti-ADI-PEG20 antibody emergence, plasma arginine concentrations remained suppressed by 18 weeks with a reciprocal increase in plasma citrulline. Tumour rebiopsies at progression revealed ASS1 re-expression as an escape mechanism. ADIPemCis was well tolerated with modest disease stabilisation in metastatic UM. Further investigation of arginine deprivation is indicated in UM including combinations with immune checkpoint blockade and additional anti-metabolite strategies.

Targeting neurotrophin and nitric oxide signaling to treat spinal cord injury and associated neurogenic bladder overactivity.

Purpose or the research: Nearly 300,000 people are affected by spinal cord injury (SCI) with approximately 18,000 new cases annually, according to the National SCI Statistics Center. SCI affects physical mobility and impairs the function of multiple internal organs to cause lower urinary tract (LUT) dysfunctions manifesting as detrusor sphincter dyssynergia (DSD) and neurogenic detrusor overactivity (NDO) with detrimental consequences to the quality of life and increased morbidity. Multiple lines of evidence now support time dependent evolution of the complex SCI pathology which requires a multipronged treatment approach of immediate, specialized care after spinal cord trauma bookended by physical rehabilitation to improve the clinical outcomes. Instead of one size fits all treatment approach, we propose adaptive drug treatment to counter the time dependent evolution of SCI pathology, with three small molecule drugs with distinctive sites of action for the recovery of multiple functions. Principal results: Our findings demonstrate the improvement in the recovery of hindlimb mobility and bladder function of spinal cord contused mice following administration of small molecules targeting neurotrophin receptors, LM11A-31 and LM22B-10. While LM11A-31 reduced the cell death in the spinal cord, LM22B-10 promoted cell survival and axonal growth. Moreover, the soluble guanylate cyclase (sGC) activator, cinaciguat, enhanced the revascularization of the SCI injury site to promote vessel formation, dilation, and increased perfusion. Major conclusions: Our adaptive three drug cocktail targets different stages of SCI and LUTD pathology: neuroprotective effect of LM11A-31 retards the cell death that occurs in the early stages of SCI; and LM22B-10 and cinaciguat promote neural remodeling and reperfusion at later stages to repair spinal cord scarring, DSD and NDO. LM11A-31 and cinaciguat have passed phase I and IIa clinical trials and possess significant potential for accelerated clinical testing in SCI/LUTD patients.

Phase 1 trial of ADI-PEG 20 and liposomal doxorubicin in patients with metastatic solid tumors.

BACKGROUND: Arginine depletion interferes with pyrimidine metabolism and DNA damage repair pathways. Preclinical data demonstrated that depletion of arginine by PEGylated arginine deiminase (ADI-PEG 20) enhanced liposomal doxorubicin (PLD) cytotoxicity in cancer cells with argininosuccinate synthase 1 (ASS1) deficiency. The objective of this study was to assess safety and tolerability of ADI-PEG 20 and PLD in patients with metastatic solid tumors. METHODS: Patients with advanced ASS1-deficient solid tumors were enrolled in this phase 1 trial of ADI-PEG 20 and PLD following a 3 + 3 design. Eligible patients were given intravenous PLD biweekly and intramuscular (IM) ADI-PEG 20 weekly. Toxicity and efficacy were evaluated according to the Common Terminology Criteria for Adverse Events (version 4.0) and Response Evaluation Criteria in Solid Tumors (version 1.1), respectively. RESULTS: Of 15 enrolled patients, 9 had metastatic HER2-negative breast carcinoma. We observed no dose-limiting toxicities or treatment-related deaths. One patient safely received 880 mg/m2 PLD in this study and 240 mg/m2 doxorubicin previously. Treatment led to stable disease in 9 patients and was associated with a median progression-free survival time of 3.95 months in 15 patients. Throughout the duration of treatment, decreased arginine and increased citrulline levels in peripheral blood remained significant in a majority of patients. We detected no induction of anti-ADI-PEG 20 antibodies by week 8 in one third of patients. CONCLUSION: Concurrent IM injection of ADI-PEG 20 at 36 mg/m2 weekly and intravenous infusion of PLD at 20 mg/m2 biweekly had an acceptable safety profile in patients with advanced ASS1-deficient solid tumors. Further evaluation of this combination is under discussion.

Stress-Induced Changes in Trophic Factor Expression in the Rodent Urinary Bladder: Possible Links With Angiogenesis.

PURPOSE: Substantive evidence supports a role of chronic stress in the development, maintenance, and even enhancement of functional bladder disorders such as interstitial cystitis/bladder pain syndrome (IC/BPS). Increased urinary frequency and bladder hyperalgesia have been reported in rodents exposed to a chronic stress paradigm. Here, we utilized a water avoidance stress (WAS) model in rodents to investigate the effect of chronic stress on vascular perfusion and angiogenesis. METHODS: Female Wistar-Kyoto rats were exposed to WAS for 10 consecutive days. Bladder neck tissues were analyzed by western immunoblot for vascular endothelial growth factor (VEGF) and nerve growth factor precursor (proNGF). Vascular perfusion was assessed by fluorescent microangiography followed by Hypoxyprobe testing to identify regions of tissue hypoxia. RESULTS: The expression of VEGF and proNGF in the bladder neck mucosa was significantly higher in the WAS rats than in the controls. There was a trend toward increased vascular perfusion, but without a statistically significant difference from the control group. The WAS rats displayed a 1.6-fold increase in perfusion. Additionally, a greater abundance of vessels was observed in the WAS rats, most notably in the microvasculature. CONCLUSION: These findings show that chronic psychological stress induces factors that can lead to increased microvasculature formation, especially around the bladder neck, the region that contains most nociceptive bladder afferents. These findings may indicate a link between angiogenesis and other inflammatory factors that contribute to structural changes and pain in IC/BPS.

Assessment of pegylated arginine deiminase and modified FOLFOX6 in patients with advanced hepatocellular carcinoma: Results of an international, single-arm, phase 2 study.

BACKGROUND: Arginine starvation depletes the micronutrients required for DNA synthesis and interferes with both thymidylate synthetase activity and DNA repair pathways in preclinical models of hepatocellular carcinoma (HCC). Pegylated arginine deiminase (ADI-PEG 20), an arginine degrader, potentiates the cytotoxic activity of platinum and pyrimidine antimetabolites in HCC cellular and murine models. METHODS: This was a global, multicenter, open-label, single-arm, phase 2 trial of ADI-PEG 20 and modified 5-fluorouracil, leucovorin, and oxaliplatin (mFOLFOX6) in patients who had HCC with Child-Pugh A cirrhosis and disease progression on ≥2 prior lines of treatment. The primary objective was the objective response rate assessed according to Response Evaluation Criteria in Solid Tumors, version 1.1. Secondary objectives were to estimate progression-free survival, overall survival, safety, and tolerability. Eligible patients were treated with mFOLFOX6 intravenously biweekly at standard doses and ADI-PEG-20 intramuscularly weekly at 36 mg/m2 . RESULTS: In total, 140 patients with advanced HCC were enrolled. The median patient age was 62 years (range, 30-85 years), 83% of patients were male, 76% were of Asian race, 56% had hepatitis B viremia, 10% had hepatitis C viremia, 100% had received ≥2 prior lines of systemic therapy, and 39% had received ≥3 prior lines of systemic therapy. The objective response rate was 9.3% (95% confidence interval [CI], 5.0%-15.4%), with a median response duration of 10.2 months (95% CI, 5.8 months to not reached). The median progression-free survival was 3.8 months (95% CI, 1.8-6.3 months), and the median overall survival was 14.5 months (95% CI, 13.6-20.9 months). The most common grade ≥3 treatment-related events were neutropenia (32.9%), white blood cell count decrease (20%), platelet count decrease (19.3%), and anemia (9.3%). CONCLUSIONS: Concurrent mFOLFOX6 plus ADI-PEG 20 exhibited limited antitumor activity in patients with treatment-refractory HCC. The study was terminated early, and no further evaluation of the combination will be pursued. LAY SUMMARY: Arginine is an important nutrient for hepatocellular carcinoma (HCC). The depletion of arginine with pegylated arginine deiminase (ADI-PEG 20), an arginine degrader, appeared to make chemotherapy (FOLFOX) work better in animal models of HCC and in patients with HCC on an early phase clinical trial. To formally test this hypothesis in the clinical setting, a large, global, phase 2 clinical trial was conducted of ADI-PEG 20 and FOLFOX in the treatment of patients with refractory HCC. The study showed limited activity of ADI-PEG 20 and FOLFOX in advanced HCC and was stopped early.

Phase 1, pharmacogenomic, dose-expansion study of pegargiminase plus pemetrexed and cisplatin in patients with ASS1-deficient non-squamous non-small cell lung cancer.

INTRODUCTION: We evaluated the arginine-depleting enzyme pegargiminase (ADI-PEG20; ADI) with pemetrexed (Pem) and cisplatin (Cis) (ADIPemCis) in ASS1-deficient non-squamous non-small cell lung cancer (NSCLC) via a phase 1 dose-expansion trial with exploratory biomarker analysis. METHODS: Sixty-seven chemonaïve patients with advanced non-squamous NSCLC were screened, enrolling 21 ASS1-deficient subjects from March 2015 to July 2017 onto weekly pegargiminase (36 mg/m2 ) with Pem (500 mg/m2 ) and Cis (75 mg/m2 ), every 3 weeks (four cycles maximum), with maintenance Pem or pegargiminase. Safety, pharmacodynamics, immunogenicity, and efficacy were determined; molecular biomarkers were annotated by next-generation sequencing and PD-L1 immunohistochemistry. RESULTS: ADIPemCis was well-tolerated. Plasma arginine and citrulline were differentially modulated; pegargiminase antibodies plateaued by week 10. The disease control rate was 85.7% (n = 18/21; 95% CI 63.7%-97%), with a partial response rate of 47.6% (n = 10/21; 95% CI 25.7%-70.2%). The median progression-free and overall survivals were 4.2 (95% CI 2.9-4.8) and 7.2 (95% CI 5.1-18.4) months, respectively. Two PD-L1-expressing (≥1%) patients are alive following subsequent pembrolizumab immunotherapy (9.5%). Tumoral ASS1 deficiency enriched for p53 (64.7%) mutations, and numerically worse median overall survival as compared to ASS1-proficient disease (10.2 months; n = 29). There was no apparent increase in KRAS mutations (35.3%) and PD-L1 (<1%) expression (55.6%). Re-expression of tumoral ASS1 was detected in one patient at progression (n = 1/3). CONCLUSIONS: ADIPemCis was safe and highly active in patients with ASS1-deficient non-squamous NSCLC, however, survival was poor overall. ASS1 loss was co-associated with p53 mutations. Therapies incorporating pegargiminase merit further evaluation in ASS1-deficient and treatment-refractory NSCLC.

Phase 1b study of pegylated arginine deiminase (ADI-PEG 20) plus Pembrolizumab in advanced solid cancers.

Background: Pegylated arginine deiminase (ADI-PEG 20) is a metabolism-based strategy that depletes arginine, resulting in tumoral stress and cytotoxicity. Preclinically, ADI-PEG 20 modulates T-cell activity and enhances the therapeutic efficacy of programmed death-1 (PD-1) inhibition. Methods: A phase 1b study, including a dose-escalation cohort and an expansion cohort, was undertaken to explore the effects of ADI-PEG 20 in combination with pembrolizumab, an anti-PD-1 antibody, for safety, pharmacodynamics, and response. CD3 levels and programmed death-ligand 1 (PD-L1) expression were assessed in paired biopsies collected prior to and after ADI-PEG 20 treatment but before pembrolizumab. Results: Twenty-five patients, nine in the dose-escalation cohort and sixteen in the expansion cohort, were recruited. Treatment was feasible with adverse events consistent with those known for each agent, except for Grade 3/4 neutropenia which was higher than expected, occurring in 10/25 (40%) patients. Mean arginine levels were suppressed for 1-3 weeks, but increased gradually. CD3+ T cells increased in 10/12 (83.3%) subjects following ADI-PEG 20 treatment, including in three partial responders (p = .02). PD-L1 expression was low and increased in 3/10 (30%) of subjects. Partial responses occurred in 6/25 (24%) heavily pretreated patients, in both argininosuccinate synthetase 1 proficient and deficient subjects. Conclusions: The immunometabolic combination was safe with the caveat that the incidence of neutropenia might be increased compared with either agent alone. ADI-PEG 20 treatment increased T cell infiltration in the low PD-L1 tumor microenvironment. The recommended phase 2 doses are 36 mg/m2 weekly for ADI-PEG 20 and 200 mg every 3 weeks for pembrolizumab.

Phase I study of ADI-PEG20 plus low-dose cytarabine for the treatment of acute myeloid leukemia.

Most acute myeloid leukemia (AML) cells are argininosuccinate synthetase-deficient. Pegylated arginine deiminase (ADI-PEG20) monotherapy depletes circulating arginine, thereby selectively inducing tumor cell death. ADI-PEG20 was shown to induce complete responses in ~10% of relapsed/refractory or poor-risk AML patients. We conducted a phase I, dose-escalation study combining ADI-PEG20 and low-dose cytarabine (LDC) in AML patients. Patients received 20 mg LDC subcutaneously twice daily for 10 days every 28 days and ADI-PEG20 at 18 or 36 mg/m2 (dose levels 1 and 2) intramuscularly weekly. An expansion cohort for the maximal tolerated dose of ADI-PEG20 was planned to further estimate the toxicity and preliminary response of this regimen. The primary endpoints were safety and tolerability. The secondary endpoints were time on treatment, overall survival (OS), overall response rate (ORR), and biomarkers (pharmacodynamics and immunogenicity detection). Twenty-three patients were included in the study, and seventeen patients were in the expansion cohort (dose level 2). No patients developed dose-limiting toxicities. The most common grade III/IV toxicities were thrombocytopenia (61%), anemia (52%), and neutropenia (30%). One had an allergic reaction to ADI-PEG20. The ORR in 18 evaluable patients was 44.4%, with a median OS of 8.0 (4.5-not reached) months. In seven treatment-naïve patients, the ORR was 71.4% and the complete remission rate was 57.1%. The ADI-PEG20 and LDC combination was well-tolerated and resulted in an encouraging ORR. Further combination studies are warranted. (This trial was registered in ClinicalTrials.gov as a Ph1 Study of ADI-PEG20 Plus Low-Dose Cytarabine in Older Patients With AML, NCT02875093).