Interstitial lung diseases (ILDs), commonly referred to as pulmonary fibrosis (PF) comprise a heterogeneous group of more than 200 disorders characterised by inflammation and/or fibrosis of the lung parenchyma, resulting in impaired gas exchange, declining lung function, and, in many cases, progressive respiratory failure. 

Previously considered rare disease, ILDs are now recognised as a major global health burden, affecting an estimated 4.7 million people worldwide and this burden is expected to increase further with the expansion of lung cancer screening programs, which identify interstitial lung abnormalities (ILAs) in approximately 2-17% of screened individuals, of whom up to 50% progress to clinically significant ILD within five years.

In Australia, ILDs are increasingly recognised as an important contributor to the burden of chronic respiratory disease, with idiopathic pulmonary fibrosis (IPF) being the most common and progressive subtype. Recent Australian studies have shown that both the incidence and prevalence of IPF have increased and almost doubled over the past decades, likely due to an ageing population, greater disease awareness, and improved diagnostic capabilities. Data from the Australasian Interstitial Lung Disease Registry (AILDR) demonstrate that, beyond IPF, conditions such as connective tissue disease-associated ILD, sarcoidosis, and hypersensitivity pneumonitis also contribute substantially to the burden of ILDs in Australia. 

The impact of ILDs is considerable for both affected individuals and the healthcare system. Patients experience substantial impairments in quality of life, functional capacity, and daily activities. In parallel, ILDs place considerable demands on healthcare resources with IPF alone estimated to cost approximately AU$299 million annually in Australia.

Despite the increasing burden of ILDs, advances in disease recognition, diagnosis, and treatment are reshaping the clinical landscape. Australia has established a strong foundation to support this shift through collaborative research networks, specialist multidisciplinary ILD services, the Centre of Research Excellence in Pulmonary Fibrosis (CRE-PF), the Pulmonary Fibrosis Australasian Clinical Trials (PACT) network, the Australasian Interstitial Lung Disease Registry (AILDR) and the Lung Foundation of Australia (LFA). Together, these initiatives have enhanced understanding of disease epidemiology, improved diagnostic pathways and earlier diagnosis and facilitated access to evidence-based therapies and clinical trials, transforming conditions that were once considered largely untreatable to ones that increasingly managed as chronic diseases. 

Perhaps most importantly, these advances have driven a paradigm shift in ILD care, evolving from a model centred primarily on supportive management to one that integrates supportive care with proactive strategies focused on earlier diagnosis, timely intervention, and personalised care, helping to preserve lung function, reduce symptoms, improve quality of life, and ultimately improve patient outcomes.

ILDs are becoming treatable

There have been significant developments in treatments for pulmonary fibrosis, particularly Idiopathic Pulmonary Fibrosis (IPF), the most common fibrotic lung disease in Australia which historically carried an expected median survival of only 2-3 years following diagnosis. Two antifibrotic medications, nintedanib and pirfenidone, are currently available through the Pharmaceutical Benefits Scheme for patients with IPF. Landmark phase III clinical trials published in 2014 demonstrated that both agents reduced the rate of lung function decline by approximately 50%, establishing for the first time that the natural history of IPF could be modified. 

Following this in 2019, the INBUILD trial demonstrated a similarly meaningful reduction in disease progression in a broader patient population, including fibrotic lung diseases arising from other causes such as connective tissue disease and hypersensitivity pneumonitis which demonstrated a Progressive Pulmonary Fibrosis (PPF) phenotype. This paved the way for nintedanib to receive PBS listing for this indication in 2022. 

Of note, the treatment landscape continues to evolve rapidly with unprecedented expansion in pulmonary fibrosis drug development. Over the two years numerous novel therapies have progressed through clinical trials. Nerandomilast, a phosphodiesterase 4B inhibitor with both antifibrotic and immunomodulatory properties, has demonstrated additional benefits in the FIBRONEER phase III studies involving patients with both IPF and PPF and has recently been approved for use in the United States and China. Rate of FVC decline was significant reduced, including for patients on background antifibrotics for IPF or PPF. Diarrhoea was the main adverse treatment effect leading to discontinuation of therapy in only a small percentage of patients. 

More recently, in the phase III TETON-1 and TETON-2 trials, Treprostinil, an inhaled compound that acts on prostacyclin pathways with anti-inflammatory, vasodilatory and antifibrotic effects, has been shown to reduce FVC decline and reduce risk of clinical worsening events for patients with IPF. Despite treatment discontinuation in nearly a third of subjects due to treatment related adverse events (mostly cough), Treprostinil nonetheless remains another treatment on the horizon to further slow the progression of IPF. These developments reinforce a growing optimism that further pharmacological interventions will be available for Australian patients with pulmonary fibrosis in the years ahead.

Non-pharmacological interventions and the management of treatable traits are now considered integral components of comprehensive care. This approach recognises that while fibrosis itself may not be reversible, many of its consequences and contributors are potentially modifiable. Addressing treatable traits, including chronic aspiration, infection prevention, anxiety and depression, sleep apnoea, oxygen therapy, poor diet and ongoing environmental or occupational exposures, may also reduce the risk of disease progression and optimise overall health status.

In addition, early palliative care input is encouraged particularly for pulmonary fibrosis patients with difficult to control symptoms. Physical deconditioning is increasingly recognised as a predictor of poorer outcomes in PF. Pulmonary rehabilitation, typically delivered over eight weeks either in person or via telehealth, has a strong evidence base demonstrating improvements in exercise capacity, symptom burden, and quality of life in patients with ILD. Systematically identifying and targeting these traits allows clinicians to deliver more personalised care and improve outcomes beyond what can be achieved with pharmacotherapy alone. 

Equally important is patient empowerment. Living with pulmonary fibrosis often requires long-term engagement with healthcare providers and sustained self-management. To support patients and their families, LFA and the CRE-PF have developed a range of educational and self-management resources that provide practical information across the spectrum of PF care, such as the RE-BUILD patient facing mobile phone app.

Looking ahead for pulmonary fibrosis

The recognition that pulmonary fibrosis is increasingly treatable has important implications for clinical practice. Timely intervention offers the best opportunity to preserve lung function, improve quality of life, and potentially alter disease trajectory. Looking forward, the future of pulmonary fibrosis management is likely to be increasingly personalised. Advances in biomarker discovery, genetic testing, quantitative imaging, and artificial intelligence may improve risk stratification, enable earlier detection, and support treatment decisions tailored to the individual patient. In parallel, the expanding range of therapeutic options is expected to shift management beyond a one-size-fits-all approach towards combination therapies and precision medicine strategies that target multiple disease pathways simultaneously.

For general practitioners, the evolving ILD landscape underscores the importance of early recognition, risk assessment, screening, monitoring, and timely referral, with particular attention to older adults with unexplained breathlessness, persistent dry cough, a family history of PF, or relevant occupational and environmental exposures. The increasing recognition of the genetic contribution to PF, including familial disease, should also prompt consideration of screening and ongoing surveillance in at-risk family members. Early specialist referral enables prompt diagnosis and access to evidence-based therapies and clinical trials, improving patient outcomes.

What was once considered an untreatable disease is increasingly becoming one in which timely diagnosis and targeted interventions can meaningfully change the patient journey and improve long-term outcomes.

Dr Ingrid Cox is a Senior Research Fellow at the Menzies Institute for Medical Research, University of Tasmania. Her research focuses on the quality of life, epidemiology, and economic burden of interstitial lung diseases (ILDs), with a particular interest in developing disease models to predict patient outcomes and evaluate the cost-effectiveness of diagnostics, interventions, and treatments. Ingrid is a physician by training and holds a Master’s degree in Health Economics and Policy from the University of Adelaide and a PhD from the University of Tasmania. She has experience spanning clinical practice, public health, health policy, and health service planning.

Dr Rob Sheehy is a Consultant Respiratory & Sleep Physician with an interest in interstitial lung disease. He is a Staff Specialist at the Princess Alexandra Hospital in Brisbane and is a Senior Lecturer for the University of Queensland. He is a CREATE research fellow with the Centre of Research Excellence in Pulmonary Fibrosis (CRE-PF) and the University of Sydney and is also a member of the CRE-PF Translation, Education and Support Subcommittee.