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Background/Objectives: Interstitial lung disease (ILD) is one of the most severe complications of rheumatoid arthritis (RA). Real-world data on antifibrotic treatment are needed. Our objective was to evaluate the real-world effectiveness and tolerability of antifibrotic agents in patients with progressive fibrosing RA-ILD. Methods: A longitudinal, retrospective, observational study was conducted on a cohort of RA-ILD patients treated with either nintedanib or pirfenidone. The data collected included pulmonary function test (PFT) results, adverse events (AEs), tolerability, and drug retention. Results: Twenty-seven patients were included; 25 (92.5%) initiated nintedanib, while two initiated pirfenidone. The median follow-up duration was 25 months (IQR 7–27). The mean decline in %pFVC and %pDLCO from ILD diagnosis to the initiation of antifibrotic therapy were −8.9% and −14.8%, respectively. After 6 months of treatment, most patients achieved stabilization in PFT: a ∆%pFVC of +1.2% (p = 0.611 compared with baseline) and a ∆%pDLCO of +3.9% (p = 0.400). Eighteen patients completed one year of therapy, with a modest improvement in %pFVC (+4.7%; p = 0.023) and stabilization in %pDLCO (−3.8%; p = 0.175). This trend persisted among the nine patients who completed 2 years of treatment (%pFVC +7.7%; p = 0.037 and %pDLCO −2.2%; p = 0.621). During the follow-up period, 15% of patients died, and 4% underwent lung transplantation. Adverse events occurred in 81% of patients, leading to discontinuation in 18.5% of cases. The most frequent adverse events were gastrointestinal events and hepatitis, leading to a permanent dose reduction of 40% for nintedanib and 14% for pirfenidone. A second antifibrotic agent was prescribed for 18.5% of the patients. At the end of the follow-up period, 63% of the total cohort remained on antifibrotic therapy. Conclusions: According to our results, antifibrotic initiation was associated with a modest improvement in the trajectory of %pFVC and stabilization in %pDLCO. The discontinuation rate in our cohort (37%) was higher than that reported in clinical trials but similar to that reported in previously published real-world studies. [ABSTRACT FROM AUTHOR]

The article outlines updated S2k guidelines from the German Respiratory Society on the pharmacological treatment of idiopathic pulmonary fibrosis (IPF) and progressive pulmonary fibroses (PPF). Topics discussed include the use of antifibrotic drugs like nintedanib and pirfenidone, the progression of fibrotic interstitial lung diseases, and considerations for initiating, discontinuing, or switching therapies in IPF and PPF management.

A severe and progressive interstitial lung disease (ILD) known as idiopathic pulmonary fibrosis (IPF) has an unknown etiology with poorly defined mechanisms of development. Among the currently prescribed pharmacological interventions for IPF, nintedanib demonstrates the ability to decelerate the deterioration of lung function and yield positive clinical outcomes. Multiple randomized placebo-controlled trials have confirmed the efficacy and acceptable safety profile of nintedanib. Real-world evidence studies also support the use of nintedanib in IPF, being an efficient and well-tolerated treatment option. It has the potential to stabilize the disease progression in patients with ILD. Patients with IPF frequently have comorbidities like diabetes and hypertension, which can exacerbate the course of disease, reduce quality of life, and decrease treatment adherence. For well-informed decision-making, it is important for healthcare professionals to recognize the position of nintedanib therapy in IPF with comorbidities. The gastrointestinal adverse effects, notably diarrhea, dominate the nintedanib safety profile. These can be effectively controlled by closely monitoring side effects, administering anti-diarrheal and anti-emetic drugs, reducing the nintedanib dose, and discontinuing it in case of severe symptoms with an option to reintroduce the treatment after side effects subside. Symptomatic interventions and monitoring of liver enzymes may reduce the occurrence of permanent treatment discontinuations. [ABSTRACT FROM AUTHOR]

Background: Idiopathic Pulmonary Fibrosis (IPF), prevalently affecting individuals over 60 years of age, has been mainly studied in young mouse models. The limited efficacy of current treatments underscores the need for animal models that better mimic an aged patient population. We addressed this by inducing pulmonary fibrosis in aged mice, using longitudinal micro-CT imaging as primary readout, with special attention to animal welfare. Methods: A double bleomycin dose was administered to 18–24 months-old male C57Bl/6j mice to induce pulmonary fibrosis. Bleomycin dosage was reduced to as low as 75% compared to that commonly administered to young (8–12 weeks-old) mice, resulting in long-term lung fibrosis without mortality, complying with animal welfare guidelines. After fibrosis induction, animals received Nintedanib once-daily for two weeks and longitudinally monitored by micro-CT, which provided structural and functional biomarkers, followed by post-mortem histological analysis as terminal endpoint. Results: Compared to young mice, aged animals displayed increased volume, reduced tissue density and function, and marked inflammation. This increased vulnerability imposed a bleomycin dosage reduction to the lowest tested level (2.5 µg/mouse), inducing a milder, yet persistent, fibrosis, while preserving animal welfare. Nintedanib treatment reduced fibrotic lesions and improved pulmonary function. Conclusions: Our data identify a downsized bleomycin treatment that allows to achieve the best trade-off between fibrosis induction and animal welfare, a requirement for antifibrotic drug testing in aged lungs. Nintedanib displayed significant efficacy in this lower-severity disease model, suggesting potential patient stratification strategies. Lung pathology was quantitatively assessed by micro-CT, pointing to the value of longitudinal endpoints in clinical trials. [ABSTRACT FROM AUTHOR]

Background and Purpose Experimental Approach Key Results Conclusion and Implications Pneumoconiosis, especially silicosis, is a prevalent occupational disease with substantial global economic implications and lacks a definitive cure. Both pneumoconiosis and idiopathic pulmonary fibrosis (IPF) are interstitial lung diseases, which share many common physiological characteristics. Because pirfenidone and nintedanib are approved to treat IPF, their potential efficacy as antifibrotic agents in advanced silicosis deserves further exploration. Thus, we aimed to evaluate the individual and combined effects of pirfenidone and nintedanib in treating advanced silicosis mice and elucidate the underlying mechanisms of their therapeutic actions via multiomics.We administered monotherapy or combined therapy of pirfenidone and nintedanib, with low and high doses, in silicosis established after 6 weeks and evaluated lung function, inflammatory responses and fibrotic status. Additionally, we employed transcriptomic and metabolomic analyses to uncover the mechanisms underlying different therapeutic strategies.Both pirfenidone and nintedanib were effective in treating advanced silicosis, with superior outcomes observed in combination therapy. Transcriptomic and metabolomic analyses revealed that pirfenidone and nintedanib primarily exerted their therapeutic effects by modulating immune responses, signalling cascades and metabolic processes involving lipids, nucleotides and carbohydrates. Furthermore, we experimentally validated both monotherapy and combined therapy yielded therapeutic benefits through two common signalling pathways: steroid biosynthesis and purine metabolism.In conclusion, pirfenidone and nintedanib, either individually or in combination, demonstrate substantial potential in advanced silicosis. Furthermore, combined therapy outperformed monotherapy, even at low doses. These therapeutic benefits are attributed to their influence on diverse signalling pathways and metabolic processes. [ABSTRACT FROM AUTHOR]

Objective: Rheumatoid arthritis-associated interstitial lung disease (RA-ILD) is a significant pulmonary complication of RA. This study tried to elucidate the mechanisms enhancing inflammation and causing lung injury in RA-ILD, focusing on the role of neutrophil extracellular traps (NETs). The study also investigated the potential benefits of nintedanib in advanced disease. Methods: Nine RA-ILD patients and nine healthy controls were included in the study. Inflammatory markers in patients' circulation were evaluated with immunoassays. The formation of NETs was examined using a citrullinated histone H3 (CitH3) ELISA and cell immunofluorescence. Inflammatory proteins expressed in neutrophils/NETs were studied with real-time qPCR and NET ELISA. To assess the effect of nintedanib, an intracellular tyrosine kinase inhibitor with antifibrotic properties, in RA-ILD a paired study was conducted in five patients before treatment administration and 16 weeks later. Results: The soluble terminal complement complex sC5b-9 and the levels of CitH3 were significantly elevated in patients with RA-ILD, compared to healthy controls. In addition, neutrophils isolated from RA-ILD patients released NETs enriched with tissue factor and interleukin-17A. Inflammatory NETs had a dynamic role, increasing the fibrotic potential of human pulmonary fibroblasts (HPFs). On the other hand, nintedanib treatment decreased NETs and sC5b-9 levels in RA-ILD patients. Conclusion: The findings propose an interplay between circulating NETs and HPFs, establishing the immunofibrotic aspects of RA-ILD. They also support the effectiveness of nintedanib in reducing key pathological processes of the disease. Further research is needed to fully understand these mechanisms and optimize treatment strategies for RA-ILD. [ABSTRACT FROM AUTHOR]

Background: The surgical treatment of concomitant lung cancer in patients with idiopathic pulmonary fibrosis is challenging due to the risk of life-threatening complications such as acute exacerbation development in the perioperative period. Few studies have investigated the role of anti-fibrotic drugs in this setting. The aim of this multicenter retrospective study was to evaluate the incidence of acute exacerbation, according to Collard, after lung resection in patients affected by concomitant idiopathic pulmonary fibrosis and lung cancer who were or were not on antifibrotic treatment. Secondary outcomes included: 30 and 90-day mortality and an estimation of overall and disease-free survival. Material and Methods: The study population consisted of patients affected by idiopathic pulmonary fibrosis who received curative-intent lung surgery in three Italian academic centers between 2015 and 2022. Patients were divided into two groups based on whether they were on perioperative treatment with anti-fibrotic drugs (chronical or prophylactic use) or not. To define predictors of acute exacerbation, univariate and multivariable exact logistic regression analysis were performed. The Kaplan–Meier method with log-rank test was used to estimate survival. Results: During the study period, n = 55 patients underwent lung resection for lung cancer, including 29 patients who were treated with antifibrotic agents. Although the sample size was small and few events were studied, the incidence of acute exacerbation was significantly lower among patient on anti-fibrotic therapy (3.4% vs. 23.1%, p = 0.044); in addition, anti-fibrotic treatment was the strong factor preventing acute exacerbation at the multivariable analysis (OR 0.089, p = 0.038). Post-operative 30- and 90-day mortality rates were not significantly lower in the anti-fibrotic treatment group (0% and 0% vs. 7.7% and 11.5%, p = 0.21 and p = 0.099, respectively). Overall and disease-free survival rates were similar. Conclusions: Considering the limitations of this retrospective study with a small sample size, anti-fibrotic perioperative treatment was associated with reduced incidence of acute exacerbation. Based on these real-world data, this pathway could be proposed as a prophylactic treatment in patients with concomitant idiopathic pulmonary fibrosis and cancer undergoing lung resection. [ABSTRACT FROM AUTHOR]

Objectives Lung ultrasound (LUS) and high-resolution CT (HRCT) are commonly used for the evaluation of interstitial lung disease (ILD). Nintedanib (NIN) is an antifibrotic therapy approved for systemic sclerosis-associated ILD (SSc-ILD). We assessed LUS and quantitative HRCT changes in SSc-ILD patients treated with NIN during a 1 year follow-up, evaluating relationships between imaging variations and functional or quality-of-life outcomes. Methods SSc-ILD patients who started NIN were enrolled and followed for 12 months. Pulmonary function tests and patient-reported outcome measures (PROMs) were assessed half-yearly and quarterly, respectively. LUS was performed quarterly evaluating the presence of B-lines (BL) and pleural line irregularities (PLI). HRCT was repeated after 1 year and quantitatively analysed with CALIPER software. Results Ten patients (70% female, mean age 62 years) were enrolled. The mean total number of both BL and PLI was constantly decreased during NIN treatment, being significantly reduced after 12 months (from 175.1 [66.7] to 120.8 [70.3] for BL, P  = 0.005; and from 50.6 [32.5] to 37.2 [22.4] for PLI, P  = 0.05). Male gender, smoking habit and baseline forced vital capacity <70% predicted were associated with worse LUS outcomes. A greater reduction in both BL and PLI was observed in those who improved in PROMs, especially modified Medical Research Council dyspnoea scale (P  = 0.016 and P  = 0.04, respectively) and Saint George's Respiratory Questionnaire (P  = 0.006 and P  = 0.026, respectively). No significant changes in the CALIPER percentages of normal parenchyma or ILD elements were observed after 12 months of NIN, thus paralleling the stabilization obtained at pulmonary function tests. Conclusion We present preliminary results on NIN effects on SSc-ILD as assessed by LUS, a useful method for frequently repeated monitoring, and CALIPER, a valid implementation whenever a HRCT is performed. [ABSTRACT FROM AUTHOR]

• Anti-fibrotic therapy of pirfenidone and nintedanib can limit the decline in lung function based on FVC in non-IPF PF-ILD patients. • However, overall improvements in 6MWD, all-cause mortality, or hospitalization were not noted between the group of patients receiving anti-fibrotic versus those receiving placebo. • The clinical benefits of anti-fibrotic therapy need to be weighed against the adverse risks of nausea/vomiting, diarrhea, anorexia/weight loss, and neurological disorders. Anti-fibrotics can reduce restrictive impairment in idiopathic pulmonary fibrosis (IPF). However, its effectiveness in non-IPF progressive fibrosing interstitial lung disease (non-IPF PF-ILD) remains uncertain. We assess the efficacy and safety of anti-fibrotics pirfenidone and nintedanib versus placebo among non-IPF PF-ILD adult patients. Meta-analysis was performed using PubMed, SCOPUS, and Cochrane databases to identify randomized controlled trials (RCTs). At respective centers, non-IPF PF-ILD was defined as clinical and radiological findings inconsistent with IPF and greater than 5 % forced vital capacity (FVC) decline, worsening radiological fibrosis or respiratory symptoms. Among seven RCTs involving 1,816 non-IPF PF-ILD patients, anti-fibrotics significantly reduced decline in FVC from baseline in milliliters (MD -66.80milliliters; P < 0.01) and percent predicted (MD -1.80 %; P < 0.01) compared to placebo. However, severity of FVC decline was less than 10 % (P = 0.33) in both groups. No significant difference in the decline of 6MWD from baseline in meters (P = 0.19) while on anti-fibrotics, although those on pirfenidone had less decline in 6MWD (MD -25.12 m; P < 0.01) versus placebo. The rates of all-cause mortality (P = 0.34), all-cause hospitalization (P = 0.44), and hospitalization for respiratory etiology (P = 0.06) were comparable in both groups. Adverse events of nausea/vomiting (54.2 % vs. 20.3 %; P < 0.01), diarrhea (65.2 % vs. 27.6 %; P = 0.02), anorexia/weight loss (23.0 % vs. 7.7 %; P < 0.01), neurological disorders (20.8 % vs. 12.6 %; P < 0.01), and events requiring therapy discontinuation were higher (18.4 % vs. 9.9 %; P < 0.01) in the anti-fibrotic group. Other adverse events of skin (P = 0.18) and respiratory disorders (P = 0.20) were equal. The advent of anti-fibrotics offers alternative treatment to reduce lung function decline. [ABSTRACT FROM AUTHOR]

Proliferative vitreoretinopathy (PVR) is a pathological process characterized by the formation of fibrotic membranes that contract and lead to recurrent retinal detachment. Pars plana vitrectomy (PPV) is the primary treatment, but recurrence rates remain high, as surgery does not address the underlying molecular mechanisms driving fibrosis. Despite several proposed pharmacological interventions, no approved therapies exist, partly due to challenges in conducting preclinical and in vivo studies for ethical and safety reasons. This review explores the potential of computational models and Digital Twins, which are increasingly gaining attention in medicine. These tools could enable the development of progressively complex PVR models, from basic simulations to patient-specific Digital Twins. Nintedanib, a tyrosine kinase inhibitor targeting PDGFR, VEGFR, and FGFR, is presented as a prototype for computational models to simulate its effects on fibrotic pathways in virtual patient cohorts. Although still in its early stages, the integration of computational models and Digital Twins offers promising avenues for improving PVR management through more personalized therapeutic strategies. [ABSTRACT FROM AUTHOR]

Purpose: In this study, we evaluated 66 patients diagnosed with adenoid cystic carcinoma (ACC) enrolled in two Korean Cancer Study Group trials to investigate the response and progression patterns in recurrent and/or metastatic ACC treated with vascular endothelial growth factor receptor tyrosine kinase inhibitors (VEGFR-TKIs). Materials and Methods: We evaluated 66 patients diagnosed with ACC who were enrolled in the Korean Cancer Study Group trials. The tumor measurements, clinical data, treatment outcomes, and progression patterns of therapy were analyzed. Results: In the 66 patients (53 receiving axitinib and 13 receiving nintedanib), the disease control rate was 61%, and three patients achieved partial response. The median follow-up, median progression-free survival (PFS), overall survival, and 6-month PFS rate were 27.6%, 12.4%, and 18.1% months and 62.1%, respectively. Among 42 patients who experienced progression, 27 (64.3%) showed target lesion progression. Bone metastasis was an independent poor prognostic factor. Conclusion: Overall, most patients demonstrated stable disease with prolonged PFS; however, prominent target lesion progression occurred in some patients. Thus, PFS may capture VEGFR-TKI efficacy better than the objective response rate. [ABSTRACT FROM AUTHOR]

Background/Objectives: Nintedanib (NTD), a triple tyrosine kinase receptor inhibitor, is the recommended first-line tackling option for idiopathic pulmonary fibrosis (IPF). Nevertheless, the adequacy of NTD is curtailed by issues associated with its low solubility, first-pass effect, poor bioavailability, and liver toxicity. The objective of our work was to develop a non-invasive intratracheal (i.t.) nanoparadigm based on NTD-loaded polymeric mixed micelles (NTD-PMMs) that can effectively treat IPF by sustaining the release of NTD, and snowballing its bioavailability, solubility, and efficacy. Methods: Design-Expert® software was used to optimize various NTD-PMMs formulations via Box–Behnken design adopting the thin-film hydration technique. The optimum formulation was chosen and in vivo tested in a rat model to explore its comparative bioavailability and toxicity. Results: The formulation composition with 309.217 mg of Soluplus, 150 mg of Tween 80, and 40 mg of sodium deoxycholate was found to fulfill the requisites of an optimum NTD-PMMs formulation. The optimum NTD-PMMs formulation divulged 90.26% entrapment efficiency with a surface charge of −14.72 mV and a nanoscale diameter of 61.36 nm. Also, it substantially sustained the release of NTD by 66.84% after 24 h and manifested a pronounced stability. In vivo histopathology investigations verified the safety of NTD-PMMs delivered intratracheally. Moreover, pharmacokinetic analyses disclosed accentuated relative bioavailability of the optimized NTD-PMMs by 2.4- and 3.82-fold as compared with both the i.t. and oral crude NTD suspensions, respectively. Conclusions: Overall, the current results elicited the potential of PMMs to serve as a promising pulmonary nanovector for the targeted delivery of NTD. [ABSTRACT FROM AUTHOR]

Randomized controlled trials have recently shown that both the IL-6 inhibitor Tocilizumab and the antifibrotic Nintedanib are efficacious for Systemic Sclerosis (SSc)-associated progressive interstitial lung disease (ILD). Since real-world clinical data on Tocilizumab/Nintedanib combination are lacking, we report on their long-term safety and efficacy. Consecutive patients who received off-label Tocilizumab for SSc plus Nintedanib for progressive ILD were retrospectively studied. Adverse events, and changes in Forced Vital Capacity (FVC), Diffucing Capacity for Carbon Monoxide (DLCO) and high resolution chest tomography (HRCT) between baseline and 6 and 12 months were assessed. Tocilizumab/Nintedanib combination was well tolerated by all 20 patients [aged 52 ± 13 years (mean ± SD), 14 women, 15 diffuse SSc, disease duration of 5.7 ± 4.9 years]; 7 of 20 patients received concomitant mycophenolate mofetil safely. No serious adverse events or laboratory abnormalities were noted. Five patients developed persistent diarrhea and 2 of them reduced dosage of Nintedanib. Baseline FVC (74%±12%) and DLCO (45%±10%) remained overall stable both at 6 months (73.5%±13% and 46%±11%, respectively) and 12 months (73%±14% and 45%±11%, respectively), regardless of disease duration. The extent of fibrotic reticular pattern in available pairs of HRCTs (n = 12) remained also stable at 12 months, whereas proportion (%) of ground glass opacities decreased from 29%±16 to 21%±14% (p = 0.048); improvement in HRCTs by almost 75% was noted in 2 of these12 patients. Tocilizumab/Nintedanib combination for one year was safe and stabilized lung function in real-world SSc patients with progressive ILD. Additional studies of this combination treatment in SSc-ILD are warranted. [ABSTRACT FROM AUTHOR]

Background and objective: Multiple randomized controlled studies have shown that pirfenidone and nintedanib are effective and safe for treating idiopathic pulmonary fibrosis. This study aimed to evaluate their efficacy, safety, and tolerability in a real-world setting. Methods: We searched PubMed, Embase, Cochrane Library, and ClinicalTrials.gov databases for real-world studies published up to March 3, 2023, on pirfenidone and nintedanib for idiopathic pulmonary fibrosis. Results: A total of 74 studies with 23,119 participants were included. After 12 months of treatment, the change from baseline in percent predicted FVC (%FVC) was − 0.75% for pirfenidone and − 1.43% for nintedanib. The change from baseline in percent predicted DLCO (%DCLO) was − 2.32% for pirfenidone and − 3.95% for nintedanib. The incidence of acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF) was 12.5% for pirfenidone and 14.4% for nintedanib. The IPF-related mortality rates of pirfenidone and nintedanib were 13.4% and 7.2%, respectively. The all-cause mortality was 20.1% for pirfenidone and 16.6% for nintedanib. In the pirfenidone group, 16.6% of patients discontinued treatment because of adverse events, and in the nintedanib group, 16.2% of patients discontinued treatment because of adverse events. The incidence of adverse events was 56.4% and 69.7% for pirfenidone and nintedanib, respectively. Conclusion: The results of this study indicate that pirfenidone and nintedanib are both effective in slowing down the decline of lung function in IPF patients in real-world settings. The incidence of adverse events with pirfenidone is lower than that with nintedanib, but both are below the clinical trial data, and no new major adverse events have been observed. The discontinuation rates due to adverse reactions of the two drugs are consistent with clinical trial data, indicating good tolerability. However, the mortality rates and AE-IPF incidence rates of these two drugs in real-world settings are higher than those in previous clinical trials, with pirfenidone patients showing a higher mortality rate. Further large-sample studies are needed to investigate the risks of these drugs in these aspects. Additionally, we recommend that future real-world studies pay more attention to patients' subjective symptoms and conduct stratified analyses of the efficacy and safety of pirfenidone and nintedanib based on factors such as patients' baseline lung function, comorbidities, and age, in order to provide more personalized medication advice for IPF patients in clinical practice. [ABSTRACT FROM AUTHOR]

Summary: Background and Aims: Nintedanib is currently a therapeutic option for idiopathic pulmonary fibrosis (IPF). Weight loss is a common complication of IPF and a side effect of nintedanib, inducing loss of skeletal muscle mass and musculoskeletal dysfunction. Thus far, few clinical studies have investigated the relationship between skeletal muscle mass and bodyweight in patients with IPF receiving nintedanib. Methods: In this analysis, we evaluated pooled data obtained from a retrospective investigation of treatment with nintedanib for >6 months in patients with IPF. We assessed changes in bodyweight and skeletal muscle mass by determining the pectoralis major and minor muscle cross-sectional areas (PMcsa) by chest computed tomography before and after nintedanib therapy. Results: In the cross-sectional study (n=55), PMcsa at baseline was 13.0±3.0 cm2 and significantly correlated with age (r=−0.31, P=0.023), bodyweight (r=0.63, P

Abstract Background Idiopathic Pulmonary Fibrosis (IPF), prevalently affecting individuals over 60 years of age, has been mainly studied in young mouse models. The limited efficacy of current treatments underscores the need for animal models that better mimic an aged patient population. We addressed this by inducing pulmonary fibrosis in aged mice, using longitudinal micro-CT imaging as primary readout, with special attention to animal welfare. Methods A double bleomycin dose was administered to 18–24 months-old male C57Bl/6j mice to induce pulmonary fibrosis. Bleomycin dosage was reduced to as low as 75% compared to that commonly administered to young (8–12 weeks-old) mice, resulting in long-term lung fibrosis without mortality, complying with animal welfare guidelines. After fibrosis induction, animals received Nintedanib once-daily for two weeks and longitudinally monitored by micro-CT, which provided structural and functional biomarkers, followed by post-mortem histological analysis as terminal endpoint. Results Compared to young mice, aged animals displayed increased volume, reduced tissue density and function, and marked inflammation. This increased vulnerability imposed a bleomycin dosage reduction to the lowest tested level (2.5 µg/mouse), inducing a milder, yet persistent, fibrosis, while preserving animal welfare. Nintedanib treatment reduced fibrotic lesions and improved pulmonary function. Conclusions Our data identify a downsized bleomycin treatment that allows to achieve the best trade-off between fibrosis induction and animal welfare, a requirement for antifibrotic drug testing in aged lungs. Nintedanib displayed significant efficacy in this lower-severity disease model, suggesting potential patient stratification strategies. Lung pathology was quantitatively assessed by micro-CT, pointing to the value of longitudinal endpoints in clinical trials.