How is eosinophilic COPD different from standard COPD?

In eosinophilic COPD, airway inflammation involves elevated eosinophils — measurable from a routine full blood count — rather than the neutrophilic pattern that predominates in most COPD. Patients with blood eosinophils ≥300 cells/µL show the greatest exacerbation-reduction benefit from anti-IL-5 biologics like mepolizumab. This phenotype accounts for roughly 10–20% of people with COPD.

Can GPs prescribe mepolizumab for COPD under the PBS?

PBS initiation requires a respiratory specialist. GPs play a key role in identifying candidates — reviewing eosinophil results from existing blood tests, documenting exacerbation history, confirming triple inhaler therapy is optimised — and then writing the referral.

First COPD biologic on the PBS — what GPs need to check

What just happened

Mepolizumab (Nucala) is now listed on the Pharmaceutical Benefits Scheme for COPD — making it the first biologic therapy to reach this milestone for the condition in Australia. For decades, pharmacological management of COPD has been dominated by inhaled therapies: bronchodilators, inhaled corticosteroids, triple combinations. These have improved symptom control and reduced exacerbations. But a new class of agent targeting the underlying inflammatory biology has not been accessible outside clinical trials. That changes with this PBS listing.

Australia records over 68,000 preventable COPD hospitalisations annually, at a healthcare cost of approximately $1.8 billion. For a subset of those patients — those with elevated blood eosinophils and a pattern of ongoing exacerbations despite optimal inhaled therapy — there is now an escalation pathway supported by phase 3 trial data that did not previously exist on the PBS.

Both-and

Who actually qualifies is narrow but real

The eligibility criteria are specific. PBS coverage requires blood eosinophils ≥300 cells/µL, at least one severe or two moderate exacerbations in the previous 12 months, at least one of those exacerbations occurring on optimised triple inhaler therapy, and no current or previous asthma diagnosis.

That last criterion draws a meaningful line. Mepolizumab is already PBS-listed for severe eosinophilic asthma. The COPD indication is separate, and any asthma history excludes a patient — the PBS criteria are explicit on this. It is not an overlap use case.

The benefit scales with the burden. Professor Gregory King put it plainly: “The bigger the problem you’re treating, the more potential benefit you’re going to get.” Patients with high exacerbation frequency and confirmed eosinophilic inflammation are the target. A patient stable on triple therapy with one mild exacerbation per year is not the profile this PBS listing was designed to serve.

What the trial data actually shows

The phase 3 MATINEE trial compared mepolizumab against placebo in patients with eosinophilic COPD. The headline result: a 21% reduction in annualised moderate-to-severe exacerbations — from 1.01 events per year on placebo to 0.80 on mepolizumab. That is a meaningful reduction in a high-burden population.

It is worth naming what this is and is not. A 21% reduction in exacerbations is not symptom elimination. Patients on mepolizumab still average approximately 0.80 exacerbations per year. Lung function does not recover — COPD remains a progressive disease. The treatment reduces the inflammatory spike that drives exacerbations in the eosinophilic phenotype, and fewer exacerbations means slower cumulative lung function decline over time. That matters at a population level, and it matters to individual patients who have been cycling through hospital admissions.

Benefit also takes time to manifest. Improvements appear through reduced exacerbation frequency rather than immediate relief, and a realistic window for assessing whether an individual is responding is six to twelve months. Setting that expectation before referral avoids the common scenario where a patient stops treatment because they “don’t feel different” three months in.

The eosinophil count that is already in the file

What this PBS listing does not require is a new investigation. The eosinophil count is part of a routine full blood count — a result most patients with COPD have from recent clinical encounters. What it requires is knowing to look at it.

Many patients currently on triple inhaler therapy for COPD have never had their eosinophil result examined as treatment-relevant. That number is now a screening tool. A count ≥300 cells/µL in a patient meeting the exacerbation history criteria becomes a reason for respiratory referral. The data is already there. It costs nothing to look.

2 cents

There is a practical task sitting in this news. For GPs with a COPD patient panel: pull up any patient who has had more than one moderate exacerbation in the past twelve months on triple therapy. Check whether a recent full blood count includes an eosinophil result. If the count is ≥300 cells/µL and they have no asthma history, they are potentially eligible for mepolizumab under the PBS and a respiratory referral is warranted.

The harder conversation is for patients who have been cycling through exacerbations for years and have understandably become sceptical that anything new will change their trajectory. COPD management in Australia has had few genuinely new pharmacological options for some time. A biologic is not a cure — but a 21% reduction in exacerbations in a patient who has been hospitalised twice in the past year is not a marginal gain.

This is general information. Whether any of this applies to a specific person’s situation — and whether they meet PBS criteria — is a clinical assessment, not an article.

Verdict: yes — worth knowing about. The first COPD biologic on the PBS is a genuine clinical development. Check your COPD patients’ eosinophil counts.

Sources cited

GPs urged to check eosinophils as COPD biologic hits PBS. Medical Republic, 10 September 2026.