Anti-Inflammatory Activity in the Low Molecular Weight Fraction of Commercial Human Serum Albumin (LMWF5A)

AMP5A modulates Toll-like receptors 7 and 8 single-stranded RNA immune responses in PMA-differentiated THP-1 and PBMC

BACKGROUND

Dysregulation of antiviral immunity has been implicated in the progression of acute respiratory syndrome coronavirus 2 infection into severe cases of coronavirus disease of 2019 (COVID-19). Imbalances in the inflammatory response drive the overabundant production of pro-inflammatory cytokines and chemokines. The low molecular weight fraction of 5% human serum albumin commercial preparation (AMP5A) is a novel biologic drug currently under clinical investigation for the treatment of osteoarthritis and the hyperinflammatory response associated with COVID-19. This study aims to elucidate AMP5A effects following the activation of immune cells with agonists of Toll-like receptor (TLR) 7 and/or 8, which detect ssRNA viral sequences.

METHODS

CXCL10 ELISAs were used to evaluate the dynamics of myeloid cells activated with CL075 and CL307, agonists of TLR7/8 and TLR7, respectively. In addition, enrichment analysis of gene sets generated by ELISA arrays was utilized to gain insight into the biologic processes underlying the identified differentially expressed cytokine profiles. Finally, relative potency (REP) was employed to confirm the involvement of mechanisms of action paramount to AMP5A activity.

RESULTS

AMP5A inhibits the release of CXCL10 from both CL075- and CL307-activated PMA-differentiated THP-1 and peripheral blood mononuclear cells. Furthermore, AMP5A suppresses a distinct set of pro-inflammatory cytokines (including IL-1β, IL-6, IL-12, and CXCL10) associated with COVID-19 and pro-inflammatory NF-κB activation. REP experiments using antagonists specific for the immunomodulatory transcription factors, peroxisome proliferator-activated receptor γ, and aryl hydrocarbon receptor, also indicate that these pathways are involved in the ability of AMP5A to inhibit CXCL10 release.

CONCLUSION

Due to the biphasic course of COVID-19, therapeutic approaches that augment antiviral immunity may be more beneficial early in infection, whereas later interventions should focus on inflammation suppression. In this study, we show that AMP5A inhibits TLR 7/8 signaling in myeloid cells, resulting in a decrease in inflammatory mediators associated with hyperinflammation and autoimmunity. Furthermore, data demonstrating that AMP5A activates immunomodulatory transcription factors found to be protective in lung disease is provided. These findings suggest that the modes and mechanisms of action of AMP5A are well suited to treat conditions involving dysregulated TLR 7/8 activation.

A Randomized Controlled Trial to Evaluate the Safety and Efficacy of a Novel Inhaled Biologic Therapeutic in Adults with Respiratory Distress Secondary to COVID-19 Infection

INTRODUCTION

Inhaled therapeutics may act to directly target and attenuate lung inflammation due to COVID-19. An inhalation form of a novel biologic drug, AMP5A, is being developed as an immunomodulatory agent to treat dysregulated immune responses and is being studied in hospitalized patients to treat respiratory complications due to COVID-19.

METHODS

A randomized, controlled, phase I trial was conducted to evaluate hospitalized adults with respiratory distress secondary to COVID-19. Patients received the standard care (SOC) for COVID-19, including respiratory therapy, corticosteroids, and antiviral therapies such as remdesivir. Patients were randomized 1:1 to inhalation treatment with AMP5A as an adjunct to SOC or to SOC alone (control). AMP5A was administered via inhalation daily for 5 days via hand-held nebulizer, non-invasive ventilator, or mechanical ventilation. Safety and clinical efficacy endpoints were evaluated.

RESULTS

Forty subjects were enrolled and randomized (n = 19 AMP5A, n = 21 control). Remdesivir was used in fewer AMP5A subjects (26%) than control (52%), and dexamethasone was administered for most subjects (84% AMP5A, 71% control). The study met its primary endpoint with no AMP5A treatment-related adverse events (AEs), and the incidence and severity of AEs were comparable between groups: 18 AEs for control (8 mild, 1 moderate, 9 severe) and 19 AEs for AMP5A (7 mild, 7 moderate, 5 severe). Notably, subjects treated with AMP5A had fewer deaths (5% vs. 24%), shorter hospital stay (8 days vs. 12 days), fewer ICU admissions (21% vs. 33%), and a greater proportion with improved clinical outcomes than control.

CONCLUSION

The phase I clinical results indicate inhaled AMP5A is safe, is well tolerated, and could lead to fewer patients experiencing deterioration or death. Based on the treatment effect (i.e., reduced mortality), a phase II trial has been initiated.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT04606784.

LMWF5A suppresses cytokine release by modulating select inflammatory transcription factor activity in stimulated PBMC

Background

Dysregulation of transcription and cytokine expression has been implicated in the pathogenesis of a variety inflammatory diseases. The resulting imbalance between inflammatory and resolving transcriptional programs can cause an overabundance of pro-inflammatory, classically activated macrophage type 1 (M1) and/or helper T cell type 1 (Th1) products, such as IFNγ, TNFα, IL1-β, and IL12, that prevent immune switching to resolution and healing. The low molecular weight fraction of human serum albumin (LMWF5A) is a novel biologic drug that is currently under clinical investigation for the treatment of osteoarthritis and the hyper-inflammatory response associated with COVID-19. This study aims to elucidate transcriptional mechanisms of action involved with the ability of LMWF5A to reduce pro-inflammatory cytokine release.

Methods

ELISA arrays were used to identify cytokines and chemokines influenced by LMWF5A treatment of LPS-stimulated peripheral blood mononuclear cells (PBMC). The resulting profiles were analyzed by gene enrichment to gain mechanistic insight into the biologic processes and transcription factors (TFs) underlying the identified differentially expressed cytokines. DNA-binding ELISAs, luciferase reporter assays, and TNFα or IL-1β relative potency were then employed to confirm the involvement of enriched pathways and TFs.

Results

LMWF5A was found to significantly inhibit a distinct set of pro-inflammatory cytokines (TNFα, IL-1β, IL-12, CXCL9, CXCL10, and CXCL11) associated with pro-inflammatory M1/Th1 immune profiles. Gene enrichment analysis also suggests these cytokines are, in part, regulated by NF-κB and STAT transcription factors. Data from DNA-binding and reporter assays support this with LMWF5A inhibition of STAT1α DNA-binding activity as well as a reduction in overall NF-κB-driven luciferase expression. Experiments using antagonists specific for the immunomodulatory and NF-κB/STAT-repressing transcription factors, peroxisome proliferator-activated receptor (PPAR)γ and aryl hydrocarbon receptor (AhR), indicate these pathways are involved in the LMWF5A mechanisms of action by reducing LMWF5A drug potency as measured by TNFα and IL-1β release.

Conclusion

In this report, we provide evidence that LMWF5A reduces pro-inflammatory cytokine release by activating the immunoregulatory transcription factors PPARγ and AhR. In addition, our data indicate that LMWF5A suppresses NF-κB and STAT1α pro-inflammatory pathways. This suggests that LMWF5A acts through these mechanisms to decrease pro-inflammatory transcription factor activity and subsequent inflammatory cytokine production.

AMBAR, an Encouraging Alzheimer's Trial That Raises Questions

Grifols' recent Alzheimer Management by Albumin Replacement (“AMBAR”) study investigated the effects of plasmapheresis with albumin replacement, plus intravenous immunoglobulin (IVIG) in some subjects, in patients with mild-to-moderate Alzheimer's disease (AD). AMBAR was a phase IIb trial in the United States and a phase III trial in Europe. There were three treatment groups (plasmapheresis with albumin replacement; plasmapheresis with low dose albumin and IVIG; plasmapheresis with high dose albumin and IVIG) and sham-treated controls. Disease progression in pooled treated patients was 66% less than control subjects based on ADAS-Cog scores (p = 0.06) and 52% less based on ADCS-ADL scores (p = 0.03). Moderate AD patients had 61% less progression, based on both ADAS-Cog and ADCS-ADL scores, than their sham-treated counterparts (p-values 0.05 and 0.002), and their CDR-Sb scores declined 53% less than their sham-treated counterparts. However, ADAS-Cog and ADCS-ADL scores were not significantly different between actively-treated and sham-treated mild AD patients, although CDR-Sb scores improved vs. baseline for treated mild AD patients. Patients administered both IVIG and albumin had less reduction in brain glucose metabolism than sham-treated patients. Questions raised by these findings include: what mechanism(s) contributed to slowing of disease progression? Is this approach as effective in mild AD as in moderate AD? Must IVIG be included in the protocol? Does age, sex, or ApoE genotype influence treatment response? Does the protocol increase the risk for amyloid-related imaging abnormalities? How long does disease progression remain slowed post-treatment? A further study should allow this approach to be optimized.

The novel immunomodulatory biologic LMWF5A for pharmacological attenuation of the "cytokine storm" in COVID-19 patients: a hypothesis

BACKGROUND

A common complication of viral pulmonary infections, such as in the ongoing COVID-19 pandemic, is a phenomenon described as a "cytokine storm". While poorly defined, this hyperinflammatory response results in diffuse alveolar damage. The low molecular weight fraction of commercial human serum albumin (LMWF5A), a novel biologic in development for osteoarthritis, demonstrates beneficial in vitro immunomodulatory effects complimentary to addressing inflammation, thus, we hypothesize that LMWF5A could improve the clinical outcomes of COVID-19 by attenuating hyperinflammation and the potential development of a cytokine storm.

PRESENTATION OF THE HYPOTHESIS

A variety of human in vitro immune models indicate that LMWF5A reduces the production of pro-inflammatory cytokines implicated in cytokine storm associated with COVID-19. Furthermore, evidence suggests LMWF5A also promotes the production of mediators required for resolving inflammation and enhances the barrier function of endothelial cultures.

TESTING THE HYPOTHESIS

A randomized controlled trial, to evaluate the safety and efficacy of nebulized LMWF5A in adults with Acute Respiratory Distress Syndrome (ARDS) secondary to COVID-19 infection, was developed and is currently under review by the Food and Drug Administration.

IMPLICATIONS OF HYPOTHESIS

If successful, this therapy may attenuate the cytokine storm observed in these patients and potentially reduce mortality, increase ventilation free days, improve oxygenation parameters and consequently lessen the burden on patients and the intensive care unit.

CONCLUSIONS

In conclusion, in vitro findings suggest that the immunomodulatory effects of LMWF5A make it a viable candidate for treating cytokine storm and restoring homeostasis to the immune response in COVID-19.

The anti-inflammatory effect of LMWF5A and N-acetyl kynurenine on macrophages: Involvement of aryl hydrocarbon receptor in mechanism of action

After a traumatic insult, macrophages can become activated leading to general inflammation at the site of injury. Activated macrophages are partially regulated by the aryl hydrocarbon receptor (AhR) which when activated suppresses inflammation by limiting the secretion of pro-inflammatory cytokines and promoting the over expression of immuno-modulatory mediators. This study aims to determine whether the low molecular weight fraction of 5% human serum albumin (LMWF5A) and N-acetyl kynurenine (NAK), an N-acetyl tryptophan (NAT) breakdown product in LMWF5A, can regulate inflammation by inhibiting macrophage activation through the AhR since kynurenine is a known AhR agonist. Using LCMS, we demonstrate that NAT is non-enzymatically degraded during accelerated aging of LMWF5A with high heat accelerating degradation. More importantly, NAK is a major degradation product found in LMWF5A. THP-1 monocytes were differentiated into macrophages using phorbol 12-myristate 13-acetate (PMA) and pre-treated with 2-fold dilutions of LMWF5A or synthetic NAK with or without an AhR antagonist (CH223191) prior to overnight stimulation with lipopolysaccharide (LPS). Treatment with LMWF5A caused a 50–70% decrease in IL-6 release throughout the dilution series. A dose-response inhibition of IL-6 release was observed for NAK with maximal inhibition (50%) seen at the highest NAK concentration. Finally, an AhR antagonist partially blocked the anti-inflammatory effect of LMWF5A while completely blocking the effect of NAK. A similar inhibitory effect was observed for CXCL-10, but the AhR antagonist was not effective suggesting additional mechanisms for CXCL-10 release. These preliminary findings suggest that LMWF5A and NAK partially promote the suppression of activated macrophages via the AhR receptor. Therefore, LMWF5A, which contains NAK, is potentially a useful therapeutic in medical conditions where inflammation is prevalent such as trauma, sepsis, and wound healing.

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LMWF5A contains degradation products of N-acetyl tryptophan (NAT).

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A major degradation product of NAT in LMWF5A is N-acetyl kynurenine (NAK).

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LMWF5A and NAK decrease IL-6 and CXCL-10 release from activated macrophages.

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AhR is partially involved in the mechanism of action for LMWF5A and NAK.

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The anti-inflammatory properties of LMWF5A are also AhR-independent.

Intra-articular injection of the anti-inflammatory compound LMWF-5A in adults with severe osteoarthritis: a double-blind prospective randomized controlled multi-center safety and efficacy trial

BACKGROUND

There are limited efficacious treatment options for severe osteoarthritis of the knee (OAK). The Low Molecular Weight Fraction of 5% human serum Albumin (LMWF-5A) is in development to treat severe OAK. This study evaluated the safety and efficacy of LMWF-5A for the signs and symptoms of OAK.

METHODS

This 12-week randomized, double-blind, controlled clinical trial was conducted at thirteen sites across the United States. Patients with symptomatic, severe OAK (Kellgren-Lawrence grade 4 disease) who were fully ambulatory and had no other conditions interfering with the study knee were randomized to a single 4 ml intra-articular injection of LMWF-5A or saline, randomized 6:1. The primary endpoint was Outcome Measures in Rheumatology-Osteoarthritis Research Society International (OMERACT-OARSI) responder rate (%), examined with a one-sided exact binomial test compared to a clinically meaningful response rate of 30%. Efficacy of LMWF-5A was also evaluated as controlled responder (%), defined as 20% improvements in both pain and function, compared to historical saline control from three previous trials. Safety was examined as the incidence and severity of adverse events (AEs). This trial was registered (clinicaltrials.gov identifier: NCT03182686).

RESULTS

In total, 168 patients were randomized; 144 subjects treated with LMWF-5A were analysed. Overall, 71% (95% CI: 63.4%-78.3%) of subjects treated with LMWF-5A met the OMERACT-OARSI responder criteria, exceeding the 30% threshold (p < 0.001). There were also significantly more responders at week 12 in the LMWF-5A arm than historical saline control (65% vs. 43%, p < 0.001). There were no drug-related serious AEs reported and no deaths or withdrawals due to adverse events.

CONCLUSION

LMWF-5A provides relief for the signs and symptoms of severe osteoarthritis, and may be an alternative therapeutic treatment option for patients with severe osteoarthritis of the knee.

Incidence of total knee replacement subsequent to intra-articular injection of the anti-inflammatory compound LMWF-5A versus saline: a long-term follow-up study to a randomized controlled trial

Background

The disease modifying potential of osteoarthritis therapies are of increasing interest, including their effects on delaying total knee replacement (TKR). To date, there have been no studies to determine the effect of LMWF-5A, a novel anti-inflammatory compound derived from human serum albumin, on delaying TKR.

Methods

We evaluated time to TKR three years after patients participated in a randomized trial of three intra-articular injections of LMWF-5A or saline. Patients were contacted via last known phone number and were asked to participate in a short nine item telephone questionnaire; verbal consent was obtained. The primary endpoint was incidence of TKR (%).

Results

In total, 39 of 45 patients responded (87% response rate). The overall incidence of TKR was 38.5% (15/39). TKR rates were higher in patients with more severe osteoarthritis defined by Kellgren-Lawrence grade 4, compared to patients with moderate osteoarthritis defined by Kellgren-Lawrence grade 3 (56% vs. 26%, p = 0.06). Overall, there were no differences in TKR rates by treatment arm (39% LMWF-5A vs. 38% saline, p = 0.92). In the severe osteoarthritis subset (n = 16), treatment with LMWF-5A resulted in a lower incidence of TKR compared to saline vehicle arm (40% vs. 83%, p = 0.15). TKR rates were significantly lower with LMWF-5A in patients who responded to treatment (14% with LMWF-5A, vs. 100% with saline, p = 0.03).

Conclusion

This study demonstrates significant delays in TKR for patients with severe osteoarthritis treated with LMWF-5A, suggesting that LMWF-5A has the potential to provide structure modifying/preserving therapy in this population.

LMWF-5A for the Treatment of Severe Osteoarthritis of the Knee: Integrated Analysis of Safety and Efficacy

The low-molecular-weight fraction of 5% human serum albumin (LMWF-5A) is being developed to treat the signs and symptoms of severe osteoarthritis of the knee. This study was a post hoc pooled analysis of 3 randomized placebo-controlled trials of a single intra-articular injection of LMWF-5A, focusing on the subset of patients with severe osteoarthritis of the knee (Kellgren-Lawrence grade 4). Patients were randomized 1:1 to receive a single 4-mL intra-articular knee injection of either LMWF-5A or saline. Safety was assessed as the incidence and severity of adverse events. Efficacy was assessed as the change from baseline to week 12 on the Western Ontario and McMaster Universities Osteoarthritis Index pain (primary outcome), stiffness, and physical function subscores and on patient global assessment scores and was presented as the least squares mean difference and 95% confidence interval. The proportion of responders was defined with the Outcome Measures in Rheumatology-Osteoarthritis Research Society International criteria for scenario D and examined with Pearson's chi-square test. For 417 patients with severe osteoarthritis of the knee, treatment with LMWF-5A resulted in a significant decrease in pain at 12 weeks compared with saline (mean difference, -0.19; 95% confidence interval, -0.34 to -0.04; P=.016), with improvements in function (mean difference, -0.15; 95% confidence interval, -0.31 to 0.01) and patient global assessment (mean difference, -0.30; 95% confidence interval, -0.49 to -0.12) and higher responder rates (64.25% vs 50.90%, P=.006). No drug-related serious adverse events and no deaths occurred, and the incidence and severity of adverse events were similar across treatment groups. This pooled analysis supports the use of LMWF-5A as a safe therapeutic agent for relief of the signs and symptoms of severe osteoarthritis of the knee. [Orthopedics. 2018; 41(1):e77-e83.].

The low molecular weight fraction of human serum albumin upregulates COX2, prostaglandin E2, and prostaglandin D2 under inflammatory conditions in osteoarthritic knee synovial fibroblasts

Background

The ability to decrease inflammation and promote healing is important in the intervention and management of a variety of disease states, including osteoarthritis of the knee (OAK). Even though cyclooxygenase 2 (COX2) has an established pro-inflammatory role, evidence suggests it is also critical to the resolution that occurs after the initial activation phase of the immune response. In this study, we investigated the effects of the low molecular weight fraction of 5% human serum albumin (LMWF-5A), an agent that has proven to decrease pain and improve function in OAK patients after intra-articular injection, on the expression of COX2 and its downstream products, prostaglandins (PGs).

Methods

Fibroblast-like synoviocytes from the synovial membrane of OAK patients were treated with LMWF-5A or saline as a control with or without the addition of interleukin-1β (IL-1β) or tumor necrosis factor α (TNFα) to elicit an inflammatory response. Cells were harvested for RNA and protein at 2, 4, 8, 12, and 24 h, and media was collected at 24 h for analysis of secreted products. COX2 mRNA expression was determined by qPCR, and COX2 protein expression was determined by western blot analysis. Levels of prostaglandin E2 (PGE2) and prostaglandin D2 (PGD2) in the media were quantified by competitive ELISA.

Results

In the presence of either IL-1β or TNFα, LMWF-5A increased the expression of both COX2 mRNA and protein, and this increase was significant compared to that observed with IL-1β- or TNFα-stimulated, saline-treated cells. Downstream of COX2, the levels of PGE2 were increased only in TNFα-stimulated, LMWF-5A-treated cells; however, in both IL-1β- and TNFα-stimulated cells, LMWF-5A increased the release of the anti-inflammatory prostaglandin PGD2.

Conclusion

LMWF-5A appears to trigger increased anti-inflammatory PG signaling, and this may be a primary component of its therapeutic mode of action in the treatment of OAK.

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Proposed mechanism of action for biologic drug to treat osteoarthritis of the knee.

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LMWF-5A affects the COX2 pathway in primary synoviocytes from osteoarthritic knees.

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LMWF-5A may promote resolution of inflammation, healing, and cartilage regeneration.

The low molecular weight fraction of human serum albumin upregulates production of 15d-PGJ2 in Peripheral Blood Mononuclear Cells

Activation of the innate immune system involves a series of events designed to counteract the initial insult followed by the clearance of debris and promotion of healing. Aberrant regulation can lead to systemic inflammatory response syndrome, multiple organ failure, and chronic inflammation. A better understanding of the innate immune response may help manage complications while allowing for proper immune progression. In this study, the ability of several classes of anti-inflammatory drugs to affect LPS-induced cytokine and prostaglandin release from peripheral blood mononuclear cells (PBMC) was evaluated. PBMC were cultured in the presence of dexamethasone (DEX), ibuprofen (IBU), and the low molecular weight fraction of 5% albumin (LMWF5A) followed by stimulation with LPS. After 24 h, TNFα, PGE2, and 15d-PGJ2 release was determined by ELISA. Distinct immunomodulation patterns emerged following LPS stimulation of PBMC in the presence of said compounds. DEX, a steroid with strong immunosuppressive properties, reduced TNFα, PGE2, and 15d-PGJ2 release. IBU caused significant reduction in prostaglandin release while TNFα release was unchanged. An emerging biologic with known anti-inflammatory properties, LMWF5A, significantly reduced TNFα release while enhancing PGE2 and 15d-PGJ2 release. Incubating LMWF5A together with IBU negated this observed increased prostaglandin release without affecting the suppression of TNFα release. Additionally, LMWF5A caused an increase in COX-2 transcription and translation. LMWF5A exhibited a unique immune modulation pattern in PBMC, disparate from steroid or NSAID administration. This enhancement of prostaglandin release (specifically 15d-PGJ2), in conjunction with a decrease in TNFα release, suggests a switch that favors resolution and decreased inflammation.