Nintedanib as an Antifibrotic in Post Covid Lung Fibrosis: Are we Really Overestimating?

Abstract

Antifibrotics were exuberantly used to treat post covid lung complications. Lung is the primary target organ in COVID-19 disease with diverse clinical and radiological presentations and outcome. It has caused minimal to moderate lung disease in some patients and in some cases caused deadly acute respiratory distress syndrome (ARDS). COVID-19 disease caused lung damage by direct virus induced alveolar damage, cytokine induced alveolar and vascular damage and microvascular thrombosis resulting into acute hypoxic respiratory failure. COVID-19 pneumonia evolved over period of three weeks in cases with ARDS as natural course of illness. Usually, ARDS resolves by fibrosis or resolution as final outcome. Similarly, in COVID-19 recovered cases of advanced disease or those suffering from ARDS are having post covid lung disease. Lung fibrosis is final radiological outcome of COVID-19 pneumonia documented in proportionately majority of cases. Post COVID lung fibrosis is considered as worrisome radiological complication observed during early phase of pandemic. Antifibrotics such as Nintedanib and Pirfenidone were used to treat post covid lung complications such as fibrosis. Both drugs were shown good antifibrotic property in clinical trials for fibrotic lung disease and observed positive outcome in restoring lung parenchyma. Time trends of final radiological outcome has evolved over months with or without treatment with antifibrotics and steroids. Importantly, Post covid lung fibrosis resolved more than fifty percent cases in six months and nearly in all cases after one year. Thus, antifibrotics were used irrationally in fibrosing lung condition of reversible type. Actually, we have overestimated post covid lung fibrosis and overtreated with antifibrotics.