Effect of Pirfenidone on Risk of Pulmonary Fibrosis in COVID-19 Patients Experiencing Cytokine Storm

Impact of anti-fibrotic medications on post-COVID-19 pulmonary fibrosis: A systematic review and meta-analysis

OBJECTIVES

The impact of anti-fibrotic medications on pulmonary fibrosis caused by COVID-19 remains inconclusive and lacks systematic investigation. This study assessed the efficacy of anti-fibrotic drugs in addressing post-COVID-19 lung fibrosis.

METHODS

We searched PubMed, Web of Science, Embase, and the Cochrane Library until June 15, 2024. The meta-analysis was performed using Review Manager. Heterogeneity was evaluated utilizing I2 statistic, and publication bias was assessed via funnel plots.

RESULTS

The study (CRD42024552847) included 7 trials with 496 participants. No significant differences were observed in chest CT score (SMD = -0.60, 95% CI: -1.33 to 0.12, P = 0.10), length of hospital stay (MD = -1.34, 95% CI: -4.39 to 1.70, P = 0.39), and mortality (OR = 0.91, 95% CI: 0.50 to 1.64, P = 0.75) between anti-fibrosis and standard treatment groups. Notable improvements in pulmonary function were observed with anti-fibrotic drugs, as indicated by FEV1%pred (MD = 23.95, 95% CI: 12.24 to 35.67, P < 0.0001) and FEV1/FVC (MD = 18.17, 95% CI: 11.96 to 24.38, P < 0.00001).

CONCLUSIONS

Anti-fibrotic medications may help reduce fibrotic lesions and improve pulmonary function in post-COVID-19 pulmonary fibrosis, but their practical use is currently based more on theory than on solid medical evidence. Currently, in clinical practice, the use of anti-fibrotic drugs in these patients primarily relies on empirical treatment. Further clinical studies are imperative to bolster its credibility for future applications.

Pirfenidone as a Cornerstone in the Management of Fibrotic Interstitial Lung Diseases and Its Emerging Applications: A Comprehensive Review

Pirfenidone is a groundbreaking antifibrotic agent that has become a cornerstone in managing fibrotic interstitial lung diseases (ILDs), particularly idiopathic pulmonary fibrosis (IPF). This review comprehensively analyzes pirfenidone's mechanisms of action, clinical efficacy, safety profile, and emerging applications beyond IPF. Pirfenidone exerts its therapeutic effects by inhibiting key pathways involved in fibrosis, including transforming growth factor-beta (TGF-β) and other pro-fibrotic cytokines. It also reduces oxidative stress and inflammation. Clinical trials have consistently demonstrated pirfenidone's ability to slow the decline in lung function, reduce disease progression, and improve survival rates in IPF patients. Furthermore, emerging evidence supports its potential use in other fibrotic ILDs and non-pulmonary fibrotic conditions, such as liver and kidney fibrosis. Despite its proven benefits, pirfenidone's safety and tolerability profiles require careful monitoring, with gastrointestinal and photosensitivity reactions being the most common adverse effects. Future research is poised to explore combination therapies, personalized treatment approaches, and novel applications of pirfenidone in a broader range of fibrotic disorders. As the field of antifibrotic therapy advances, pirfenidone remains a pivotal agent with the potential to significantly impact the management of fibrotic diseases across multiple organ systems. This review aims to provide clinicians and researchers with a detailed understanding of pirfenidone's current role and prospects in treating fibrosis.

Use of pirfenidone in fibrotic interstitial lung diseases and beyond: a review

The pathophysiological mechanisms involved in fibrotic interstitial lung diseases (FILDs) are akin to those observed in idiopathic pulmonary fibrosis (IPF), implying the potential for shared therapeutic approaches. Pirfenidone exhibits antifibrotic and anti-inflammatory properties, making it the first small-molecule drug approved for treating IPF. Pirfenidone has been utilized in IPF treatment for more than one decade. However, guidelines for progressive pulmonary fibrosis (PPF) treatment suggest that further research and evidence are needed to fully comprehend its efficacy and safety across various PPF subtypes. In recent years, numerous studies have explored the use of pirfenidone in treating non-IPF FILD. Herein, we provide an overview of the latest research data on application of pirfenidone in occupational-related ILD, connective tissue disease-associated ILD, post-coronavirus disease-2019 pulmonary fibrosis, and other conditions. We summarize the level of evidence and highlight challenges associated with using pirfenidone in different FILDs to offer clinical guidance.

SARS-CoV-2 Spike Protein Induces Oxidative Stress and Senescence in Mouse and Human Lung

BACKGROUND/AIM

There is concern that people who had COVID-19 will develop pulmonary fibrosis. Using mouse models, we compared pulmonary inflammation following injection of the spike protein of SARS-CoV-2 (COVID-19) to radiation-induced inflammation to demonstrate similarities between the two models. SARS-CoV-2 (COVID-19) induces inflammatory cytokines and stress responses, which are also common to ionizing irradiation-induced acute pulmonary damage. Cellular senescence, which is a late effect following exposure to SARS-CoV-2 as well as radiation, was investigated.

MATERIALS AND METHODS

We evaluated the effect of SARS-CoV-2 spike protein compared to ionizing irradiation in K18-hACE2 mouse lung, human lung cell lines, and in freshly explanted human lung. We measured reactive oxygen species, DNA double-strand breaks, stimulation of transforming growth factor-beta pathways, and cellular senescence following exposure to SARS-CoV-2 spike protein, irradiation or SARS-COV-2 and irradiation. We also measured the effects of the antioxidant radiation mitigator MMS350 following irradiation or exposure to SARS-CoV-2.

RESULTS

SARS-CoV-2 spike protein induced reactive oxygen species, DNA double-strand breaks, transforming growth factor-β signaling pathways, and senescence, which were exacerbated by prior or subsequent ionizing irradiation. The water-soluble radiation countermeasure, MMS350, reduced spike protein-induced changes.

CONCLUSION

In both the SARS-Co-2 and the irradiation mouse models, similar responses were seen indicating that irradiation or exposure to SARS-CoV-2 virus may lead to similar lung diseases such as pulmonary fibrosis. Combination of irradiation and SARS-CoV-2 may result in a more severe case of pulmonary fibrosis. Cellular senescence may explain some of the late effects of exposure to SARS-CoV-2 spike protein and to ionizing irradiation.

CTHRC1: An Emerging Hallmark of Pathogenic Fibroblasts in Lung Fibrosis

Pulmonary fibrosis is a chronic, progressive, irreversible lung disease characterized by fibrotic scarring in the lung parenchyma. This condition involves the excessive accumulation of extracellular matrix (ECM) due to the aberrant activation of myofibroblasts in the alveolar environment. Transforming growth factor beta (TGF-β) signaling is a crucial driver of fibrogenesis because it promotes excessive ECM deposition, thereby leading to scar formation and lung damage. A primary target of TGF-β signaling in fibrosis is Collagen Triple Helix Repeat Containing 1 (CTHRC1), a secreted glycoprotein that plays a pivotal role in ECM deposition and wound repair. TGF-β transcriptionally regulates CTHRC1 in response to tissue injury and controls the wound healing response through functional activity. CTHRC1 may also play an essential role in re-establishing and maintaining tissue homeostasis after wound closure by modulating both the TGF-β and canonical Wnt signaling pathways. This dual function suggests that CTHRC1 regulates tissue remodeling and homeostasis. However, deregulated CTHRC1 expression in pathogenic fibroblasts has recently emerged as a hallmark of fibrosis in multiple organs and tissues. This review highlights recent studies suggesting that CTHRC1 can serve as a diagnostic and prognostic biomarker for fibrosis in idiopathic pulmonary fibrosis, systemic sclerosis, and post-COVID-19 lung fibrosis. Notably, CTHRC1 expression is responsive to antifibrotic drugs that target the TGF-β pathway, such as pirfenidone and bexotegrast, indicating its potential as a biomarker of treatment success. These findings suggest that CTHRC1 may present new opportunities for diagnosing and treating patients with lung fibrosis.

Investigational pharmacological agents for the treatment of ARDS

INTRODUCTION

Acute Respiratory Distress Syndrome (ARDS) is a heterogeneous form of lung injury with severe hypoxemia and bilateral infiltrates after an inciting event that results in diffuse lung inflammation with a high mortality rate. While research in COVID-related ARDS has resulted in several pharmacotherapeutic agents that have undergone successful investigation, non-COVID ARDS studies have not resulted in many widely accepted pharmacotherapeutic agents despite exhaustive research.

AREAS COVERED

The aim of this review is to discuss adjuvant pharmacotherapies targeting non-COVID Acute Lung Injury (ALI)/ARDS and novel therapeutics in COVID associated ALI/ARDS. In ARDS, variable data may support selective use of neuromuscular blocking agents, corticosteroids and neutrophil elastase inhibitors, but are not yet universally used. COVID-ALI/ARDS has data supporting the use of IL-6 monoclonal antibodies, corticosteroids, and JAK inhibitor therapy.

EXPERT OPINION

Although ALI/ARDS modifying pharmacological agents have been identified in COVID-related disease, the data in non-COVID ALI/ARDS has been less compelling. The increased use of more specific molecular phenotyping based on physiologic parameters and biomarkers, will ensure equipoise between groups, and will likely allow more precision in confirming pharmacological agent efficacy in future studies.

Experimental drugs in randomized controlled trials for long-COVID: what's in the pipeline? A systematic and critical review

INTRODUCTION

Over three years have passed since the emergence of coronavirus disease 2019 (COVID-19), and yet the treatment for long-COVID, a post-COVID-19 syndrome, remains long overdue. Currently, there is no standardized treatment available for long-COVID, primarily due to the lack of funding for post-acute infection syndromes (PAIS). Nevertheless, the past few years have seen a renewed interest in long-COVID research, with billions of dollars allocated for this purpose. As a result, multiple randomized controlled trials (RCTs) have been funded in the quest to find an effective treatment for long-COVID.

AREAS COVERED

This systematic review identified and evaluated the potential of current drug treatments for long-COVID, examining both completed and ongoing RCTs.

EXPERT OPINION

We identified four completed and 22 ongoing RCTs, investigating 22 unique drugs. However, most drugs were deemed to not have high potential for treating long-COVID, according to three pre-specified domains, a testament to the ordeal of treating long-COVID. Given that long-COVID is highly multifaceted with several proposed subtypes, treatments likely need to be tailored accordingly. Currently, rintatolimod appears to have modest to high potential for treating the myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) subtype, LTY-100 and Treamid for pulmonary fibrosis subtype, and metformin for general long-COVID prevention.