Why Global Lung Metrics Aren’t Enough: The Case for Regional Imaging Biomarkers

Respiratory drug development still leans heavily on familiar measurements. FEV1, DLCO, conventional pulmonary function testing, and walking-based assessments remain deeply embedded in trial design for good reason: they are standardized, widely understood, and historically acceptable to regulators.

But the reality of lung disease is rarely global. Many pulmonary disorders evolve unevenly, and many therapies may not act in a perfectly uniform way across the lung, particularly with inhaled administration. That is where metrics measuring the sum total of the lungs begin to show their limits. They summarize, but they also smooth out. They capture broad functional change, yet they may miss where disease is concentrated, where a treatment is having a localized effect, or where early biological response is beginning to emerge. Regional imaging biomarkers have gained attention precisely because they increase the ability to provide granularity.

Why Traditional Global Lung Metrics Reach Their Limits in Clinical Trials

Traditional global lung metrics still do important work in respiratory development. Sponsors continue to rely on them because they are practical, reproducible when properly performed, and easy to place in a historical context. FEV1 remains central in many airway disease programs; DLCO is relevant in selected fibrotic and vascular indications. Pulmonary function testing (PFT) more broadly offers a language that regulators, clinicians, and statisticians all understand.

The problem is not that these tools have become useless. The problem is that they do not tell the whole story. In heterogeneous diseases such as COPD, ILD, or severe asthma, the signal of interest may appear in certain regions of the lung while others remain relatively unchanged. A whole-lung metric may record only a modest change, even when something clinically meaningful is happening regionally. That becomes especially relevant in Phase II settings, where sponsors often must decide whether a mechanism is truly active or a program deserves further investment.

In other words, total lung metrics are often directionally helpful, but they can be insensitive to spatial complexity. As respiratory R&D becomes more phenotype-driven and more mechanism-aware, that limitation starts to matter more.

What Regional Imaging Biomarkers Actually Measure

Regional imaging biomarkers are designed to capture spatial heterogeneity inside the lung rather than reducing pulmonary behavior to a single summary number. They can reveal where ventilation is impaired, where perfusion is altered, how structural damage is distributed, and whether treatment-related change occurs in these measures.

That makes them especially useful in conditions where heterogeneity is not incidental but central to the disease process. While the images may provide a lot of information by themselves, their role is not solely to generate prettier images or more data; their real value lies in making regional structural information measurable in a way that can support development decisions.

Ventilation heterogeneity

Ventilation heterogeneity refers to the uneven distribution of airflow across different lung regions. In practice, many patients do not experience pulmonary disease as a uniform decline. Certain zones may be under-ventilated while others remain relatively preserved, creating a patchwork pattern that standard spirometry cannot regionalize.

Regional imaging biomarkers make this patchiness more available. That matters when early physiological changes are subtle enough to be diluted by a global readout.

Regional perfusion and structure–function relationships

Perfusion and blood vessel volume measurements add another layer to the picture. In some diseases, changes in blood flow and vessel size volumes, parenchymal structure, and ventilation are linked in ways with classic outcome measures that are clinically meaningful and can reveal more about the disease state than total lung measures (e.g. FEV1). Imaging biomarkers can help show whether poorly ventilated regions are also poorly perfused, or whether structural abnormalities are beginning to align with measurable functional decline.

For pharmaceutical companies, this is useful, as it reveals regional flow impairments in blood vessels and airways, and can strengthen interpretation when showing relationships with classic outcomes (FEV1, FVC, DLCO). A dataset that combines regional structure and function can often say more about the mechanism than a broad functional average.

Localized treatment response

Not every respiratory therapy produces a global response. Some effects are regional by nature, especially in early development or in therapies aimed at highly localized inflammatory or structural abnormalities. In those cases, global endpoints may under-represent the benefit.

Regional biomarkers can help uncover that. They make it easier to see whether a therapy is active where it should be active, even if the whole-lung average remains relatively flat. That is often where they become strategically valuable.

Why Regional Biomarkers Matter for Endpoint Strategy

Endpoint strategy is ultimately about sensitivity, credibility, and fit. The pharmaceutical industry needs to know not only whether an endpoint is accepted, but whether it is capable of detecting the kind of change their therapy is likely to produce. In respiratory trials, that question becomes more complicated when disease expression is regionally uneven.

Regional biomarkers matter because they can sharpen the evidentiary picture. They may reveal a treatment effect earlier, clarify which patients are responding, or help show that a biological mechanism is doing what it was designed to do. That does not automatically make them primary endpoints, but it does make them increasingly relevant to endpoint architecture.

Detecting signal earlier

Earlier signal detection is one of the most compelling reasons to use regional biomarkers. In some studies, regional improvements are visible before classic measures (e.g. FEV1) move enough to be considered persuasive. That can be highly valuable in early-phase decision-making, where the goal is to understand whether the therapy is biologically active and worth developing further.

For internal teams, that kind of evidence can change the tone of a program. It gives development leaders something more concrete than a weak trend line.

Improving patient stratification

Regional biomarkers can also support better patient selection. When a disease is biologically or structurally heterogeneous, it makes sense to identify subgroups whose lung pattern is more likely to align with the treatment hypothesis. This can improve trial efficiency and reduce the risk of mixing responders and non-responders into the same analytical pool.

Better stratification rarely solves everything. But it often improves interpretability, and in respiratory development, that alone can be decisive.

Strengthening proof of mechanism

A positive primary PFT endpoint (e.g. FEV1. FVC) can suggest efficacy. A regional imaging signal can help explain why that efficacy exists. This is particularly important in mechanism-driven programs, where sponsors want evidence that a therapy is acting in the expected anatomical or physiological context.

That kind of proof does not replace hard clinical outcomes, but it often strengthens confidence in the program and helps shape later-stage design choices.

Where Regional Imaging Biomarkers Are Gaining Ground

Regional imaging biomarkers are not equally relevant across all pulmonary indications. Their value tends to rise in diseases marked by structural complexity, uneven disease burden,  treatment complexity (e.g. biologics), or treatment effects that are unlikely to be picked up uniformly across the lung. In those contexts, they are moving from exploratory tools to serious development assets.

What is striking is not just that they are being used more often. It is that they are increasingly being used with a clearer purpose: to enrich populations, refine endpoints, and give programs a better chance of detecting true treatment effects.

COPD and emphysema

COPD and emphysema are obvious candidates for regional imaging because disease burden is often patchy. Destruction, airflow limitation, air trapping, and ventilation defects do not always spread evenly across the lung. A global metric can capture overall severity, but it may miss where treatment is having a local effect—or where disease is progressing despite apparently stable whole-lung function.

That makes regional biomarkers useful for both baseline characterization and endpoint enrichment. In selected COPD programs, they can offer a more precise view of therapeutic impact than conventional functional measures alone.

Interstitial lung disease

In interstitial lung disease, progression can be subtle, uneven, and hard to capture early. A sponsor may need more than exclusion criteria to understand whether a therapy is altering the biological course of disease. Regional imaging can help describe where fibrotic burden is changing and how structural evolution relates to function over time.

This is one reason imaging-based evidence has become increasingly relevant in ILD development. It does not solve every endpoint challenge, but it can provide a more informative map of progression and how effective treatment may halt it.

Asthma and inflammatory phenotypes

Asthma is often thought of in functional or symptomatic terms, but imaging can add value in selected phenotypes, particularly when small airways dysfunction or regionally uneven ventilation is part of the disease biology. In inflammatory programs, imaging may also help distinguish which patterns of disease (e.g. mucus plugs, air trapping) are most likely to respond.

Here, the role of regional imaging biomarkers can be supportive or dominant, depending on the trial phase. They can be primary in phases 4, while in earlier phases they are more often secondary or exploratory,  

Why Global Endpoints Still Matter—But No Longer Tell the Whole Story

None of this means global endpoints (e.g. FEV1 or FVC) have lost relevance. They remain central to regulatory discussion, historical benchmarking, and broad clinical interpretation. Sponsors still need them. Investigators still trust them. They continue to anchor the evidentiary framework of many pulmonary programs.

What has changed is the assumption that they are enough on their own. Increasingly, they are being asked to coexist with more regional and more mechanistic forms of evidence. That combination is where the field seems to be heading: not toward abandonment of metrics that measure the lung in its total, but toward a more layered endpoint strategy in which total lung measures provide comparability and where regional measures provide supportive evidence.

Operational Challenges in Using Regional Imaging Biomarkers

The scientific rationale for regional imaging is often easier to articulate than the operational model required to support it. Once these biomarkers enter multicenter trials, questions of acquisition consistency, image quality, analysis methodology, and reproducibility become unavoidable. A promising biomarker can lose much of its value if site-level image acquisition is inconsistent or if interpretation drifts over time.

For the pharmaceutical industries and CROs, this is the real tension. Regional imaging biomarkers may improve sensitivity, but they also raise the bar operationally. Their success depends not only on what they measure, but on whether sufficient standardized image acquisition control measures are used across sites and patient visits.

Imaging standardization across sites

Everything starts with acquisition. If sites do not follow aligned imaging protocols, differences in timing, equipment settings, reconstruction parameters, or patient handling can create avoidable variability. Once that happens, the regional signal becomes harder to trust.

This is why imaging-focused studies often require unusually strong startup discipline. Site qualification, detailed manuals, and practical protocol training are not optional extras. They are part of the endpoint strategy itself.

Central review and quantitative consistency

Regional imaging biomarkers usually need centralized interpretation. That may take the form of central reading, quantitative analysis, or hybrid models that combine both. The point is not just oversight. It is consistency—across sites, scans, readers, and time.

Without centralization, subtle differences in interpretation can quickly erode confidence in the dataset. With it, research programs stand a better chance of turning technical complexity into credible evidence.

Regulatory readiness and validation

A regional imaging biomarker can be scientifically impressive and still not be ready for a regulatory-facing role. The pharmaceutical industry must think carefully about validation status, reproducibility, biological relevance, and how clearly the biomarker links to meaningful outcomes. The burden is different if the measure is exploratory rather than primary, but the question of defensibility never disappears.

That is why the validation strategy matters early. Waiting to generate data until late development to ask whether a biomarker is fit for purpose is usually too late.

Why Pharma Turns to Specialized Imaging Partners

Most pharmaceutical industry does not lack interest in imaging. What they often lack is the infrastructure needed to use complex imaging biomarkers consistently across real trial settings. Regional imaging requires more than scanners and data transfer. It requires acquisition discipline, central analysis capability, endpoint-specific quality control, and teams that understand both respiratory disease and imaging operations.

Specialized imaging partners become valuable at exactly that point. They help transform regional biomarkers from a technically attractive idea into something that is scalable and development teams can actually use — something reliable enough to support interpretation, influence endpoint strategy, and strengthen the overall quality of the evidence package.

Better Regional Insight Can Lead to Better Respiratory Trials

Regional imaging biomarkers are attracting attention for a simple reason: they reveal aspects of disease and treatment response that whole lung metrics can miss. In heterogeneous pulmonary disorders, added insight can improve endpoint sensitivity, sharpen patient selection, and make treatment effects easier to interpret.

Total lung endpoints remain foundational, but modern respiratory trials increasingly need more than a whole-lung average. Sponsors that combine whole lung credibility with regional insight are often better positioned to understand what their data is really saying—and to build trials that generate stronger, more decision-ready evidence.

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