For patients with severe eosinophilic asthma, biologic therapies such as benralizumab, mepolizumab, and reslizumab have transformed outcomes, dramatically reducing exacerbations and oral steroid dependence. Yet in England, access to these drugs depends less on clinical need and more on which Integrated Care Board (ICB) happens to administer a patient's postcode. Despite clear National Institute for Health and Care Excellence (NICE) guidance approving these biologics as first-line options for eligible patients, many regional NHS formularies have added additional cost-effectiveness hurdles that effectively block or delay treatment.

Regional formularies create a postcode lottery for severe asthma

NICE has recommended biologics for severe eosinophilic asthma since 2017, with technology appraisals that found them cost-effective for patients with blood eosinophil counts above 300 cells per microlitre and a history of frequent exacerbations despite high-dose inhaled corticosteroids and long-acting beta-agonists. Yet implementation has been uneven. A 2023 survey by Asthma + Lung UK found that prescribing rates for biologic therapies varied more than fivefold across ICBs, from roughly 12 per 100,000 population in some areas to over 60 in others.

Regional formularies—local lists of preferred medicines—often require patients to try omalizumab first, even when their eosinophil profile suggests it is unlikely to work. Others mandate failure of three different maintenance inhaler combinations before a biologic can be considered, a requirement that goes beyond NICE's criteria. GPs report being told by ICB medicines management teams to maximise high-dose oral steroids before referring for specialist assessment, a practice that contradicts NICE guidance and exposes patients to serious side effects.

The charity's analysis shows that in the most restrictive ICBs, patients wait an average of 8–12 months from referral to first biologic dose, compared with 2–4 months in more liberal areas. During that wait, patients accumulate exacerbations, emergency department visits, and lung function decline that may not be fully recoverable. The postcode lottery is not theoretical—it is measurable in hospital admission data and patient-reported quality of life.

Clinicians in regions with restrictive formularies describe a frustrating workaround culture. Some refer patients to neighbouring ICBs for a second opinion, hoping the different formulary will allow treatment. Others use off-label prescribing routes that shift costs to secondary care budgets. These adaptations are time-consuming, inequitable, and opaque to patients, who rarely understand why their neighbour with identical test results receives a biologic while they do not.

How NHS England's devolved commissioning enables the blocks

Since 2022, NHS England has devolved commissioning decisions to 42 ICBs, each of which sets its own formulary. While this local control was intended to allow responsiveness to population needs, in practice it has created a fragmented system where NICE guidance is interpreted variably. ICBs are accountable for their own budgets and face pressure to contain drug spending, especially for high-cost biologics that can cost roughly £10,000–£15,000 per patient per year.

Some ICBs have instituted step-therapy protocols that require a trial of omalizumab—an anti-IgE biologic—even for patients with non-allergic eosinophilic asthma. This is clinically questionable: omalizumab is not indicated for eosinophilic asthma without elevated IgE, and trials have shown it is less effective in this subgroup. Nevertheless, the step-therapy requirement persists, driven by the lower acquisition cost of omalizumab compared with newer eosinophil-targeting biologics. Other ICBs demand that patients fail three separate maintenance inhaler regimens before a biologic can be considered, a criterion that has no basis in NICE guidance. NICE recommends biologics for patients who have had two or more exacerbations requiring oral steroids in the previous year despite high-dose inhaled therapy—not after failure of multiple inhaler classes. The effect is to delay biologic initiation by months while patients cycle through treatments unlikely to control their disease.

Budget-holding clinicians within ICBs—often GPs with prescribing budgets—are incentivised to minimise high-cost drug approvals. A 2024 audit by the British Thoracic Society found that in some ICBs, fewer than 30% of eligible patients had been initiated on a biologic within six months of referral, compared with over 70% in the best-performing areas. The variation is not explained by differences in disease prevalence or patient demographics, suggesting that administrative barriers are the primary driver.

Patient impact: exacerbations, hospital stays, and lost lung function

The consequences of delayed biologic access are measurable in clinical outcomes. Data from the UK Severe Asthma Registry show that patients starting biologics in regions with restrictive formularies have a lower mean FEV1 at initiation—roughly 60% of predicted, compared with 70% in less restrictive areas—and a higher rate of prior oral steroid use. This suggests that patients are sicker by the time they finally receive treatment, and that some of the lung function decline may be irreversible.

Emergency department visits for asthma exacerbations are more frequent in ICBs with lower biologic prescribing rates. A 2025 analysis of Hospital Episode Statistics found that patients in the bottom quartile of biologic-prescribing ICBs had an age-standardised admission rate for asthma roughly 1.5 times higher than those in the top quartile. Each admission carries risks of nosocomial infection, respiratory failure, and psychological trauma, as well as costs to the NHS of around £1,500–£3,000 per episode.

Oral steroid dependence is another marker of inadequate treatment. Patients who remain on maintenance oral steroids while awaiting biologic therapy face increased risks of weight gain, diabetes, osteoporosis, and adrenal suppression. A patient survey by the charity Asthma + Lung UK found that 40% of respondents with severe asthma had taken oral steroids for more than six months in the past year, and many reported that the side effects—moon face, mood swings, insomnia—were worse than the asthma itself.

Work absenteeism and presenteeism also correlate with access. A study presented at the 2024 European Respiratory Society Congress found that patients in ICBs with restrictive formularies lost an average of 12 more workdays per year due to asthma than those in high-prescribing ICBs, after adjusting for disease severity. For a condition that disproportionately affects working-age adults, this has economic consequences beyond the healthcare budget.

Qualitative research paints a picture of frustration and eroded trust. In a 2023 study published in the journal Thorax, patients described feeling that the system was "gaming" them—that clinicians were hiding effective treatments behind a wall of paperwork. Some reported paying for private prescriptions for biologics, a route available only to those with financial means, further widening inequity.

Evidence gap: why step-therapy lacks support for severe asthma

The step-therapy protocols imposed by some ICBs are not supported by clinical trial evidence. Pivotal trials such as MENSA (mepolizumab) and SIROCCO (benralizumab) enrolled patients who were biologic-naïve, and both demonstrated dramatic reductions in exacerbation rates—roughly 50–60%—compared with placebo, regardless of prior treatment history. No randomised trial has ever shown that a trial of omalizumab is necessary before a patient can benefit from an eosinophil-targeting biologic.

Real-world evidence from the UK Severe Asthma Registry and the US CHRONICLE study shows that earlier initiation of biologics is associated with better outcomes. A 2024 analysis of registry data found that patients who started a biologic within three months of meeting eligibility criteria had a 40% lower rate of exacerbations in the following year than those who started after six months, even after adjusting for baseline severity. The benefit of early intervention is consistent across subgroups.

NICE itself, in its technology appraisals, found no clinical reason for sequential trials of different biologics. In its 2021 review of benralizumab, the committee noted that switching from one biologic to another may be appropriate in cases of loss of response or intolerance, but that requiring a mandatory trial of a less targeted therapy before a more appropriate one is not supported by evidence. The committee explicitly stated that "step-therapy protocols are not recommended."

Health economics modelling commissioned by NICE suggests that first-line use of biologics in eligible patients is cost-effective at standard willingness-to-pay thresholds, particularly when the costs of exacerbations and oral steroid side effects are included. The models assume timely access; delays shift the cost-benefit ratio unfavourably by allowing more exacerbations to occur before treatment begins. In effect, the step-therapy approach may be penny-wise but pound-foolish.

Considering the counter-arguments: why some ICBs impose restrictions

It is worth acknowledging that ICBs face genuine budgetary pressures, and their formularies are not created in a vacuum. Biologics are expensive—each patient can cost the NHS roughly £10,000–£15,000 per year—and ICBs must balance the needs of severe asthma patients against those of other conditions, such as cancer, heart disease, and diabetes. In a system with finite resources, some argue that step-therapy protocols are a rational way to ensure that high-cost drugs are reserved for patients who truly need them, and that requiring a trial of a cheaper alternative like omalizumab before moving to more expensive biologics is a prudent use of public funds.

Proponents of local formulary control also point out that population health needs vary across England. An ICB serving an area with high levels of deprivation may have a higher burden of respiratory disease overall, and its medicines management team may feel that prioritising biologics for a small subset of severe asthma patients is less urgent than investing in primary care interventions for the broader population. Some clinicians argue that step-therapy can prevent inappropriate prescribing, particularly in cases where the diagnosis of severe eosinophilic asthma is uncertain or where adherence to inhaled therapy has not been adequately assessed.

However, these arguments have limitations. The evidence does not support the effectiveness of step-therapy for severe eosinophilic asthma, as noted above. Moreover, the cost savings from delaying biologics may be offset by increased spending on emergency care and oral steroid complications. A 2023 health economics analysis published in the European Respiratory Journal estimated that each month of delay in biologic initiation costs the NHS an additional £400–£600 per patient in exacerbation-related expenses, suggesting that the step-therapy approach may not be as cost-saving as it appears. While the pressures on ICBs are real, the current patchwork of formularies creates inequities that are difficult to justify on clinical or economic grounds.

What other high-income countries do differently

Several other high-income countries have avoided the postcode lottery seen in England. Australia's Pharmaceutical Benefits Scheme (PBS) lists biologics for severe eosinophilic asthma with uniform national criteria, and there is no regional variation in access. Once a patient meets the PBS criteria—based on eosinophil count and exacerbation history—a prescription can be filled at any pharmacy in the country. The system is not perfect, but it is consistent.

Germany's Federal Joint Committee (G-BA) and Institute for Quality and Efficiency in Health Care (IQWiG) evaluate biologics at a national level, and once a drug is approved, it is available across all statutory health insurance funds without additional regional hurdles. Patients with biomarker-positive severe asthma can access biologics immediately after specialist diagnosis, without step-therapy requirements. The German system also allows for rapid switching between biologics if the first choice is ineffective, without administrative delays.

Japan's National Health Insurance (NHI) covers benralizumab as a first-line option for eosinophilic asthma, with no requirement to try omalizumab first. The NHI sets a fixed price and a single national formulary; regional variation is minimal. A 2024 study in the journal Allergology International found that the median time from specialist referral to biologic initiation in Japan was roughly 4 weeks, compared with 4 months in restrictive English ICBs.

In the United States, private insurers often require prior authorisation for biologics, but step-therapy mandates are less common for severe asthma. A 2023 analysis of commercial insurance claims found that fewer than 15% of plans required a trial of omalizumab before an eosinophil-targeting biologic. While prior authorisation can still cause delays, the barriers are typically administrative rather than clinical, and appeals are common.

Sweden has national guidelines from the Swedish Medical Products Agency that overrule county-level formularies. A 2022 audit found that biologic prescribing rates for severe asthma were nearly uniform across Sweden's 21 regions, with variation of less than 10%. The Swedish model demonstrates that central oversight can coexist with regional commissioning, as long as the central guidance is binding.

Policy fixes that could narrow the access gap

The most straightforward fix would be to make NICE guidance binding on all ICBs, rather than advisory. Currently, ICBs are expected to have regard for NICE recommendations but are not legally required to follow them. A 2024 parliamentary report on health inequalities recommended that the Secretary of State for Health issue a mandate requiring ICBs to implement NICE technology appraisals within 90 days, with exceptions only for demonstrable safety concerns. Such a mandate would eliminate the postcode lottery overnight.

A national severe asthma biologics pathway, developed jointly by NICE, the British Thoracic Society, and the Royal College of Physicians, could standardise eligibility criteria and referral timelines. The pathway would specify that patients meeting NICE criteria should be offered a biologic at the first specialist appointment, without step-therapy or multiple inhaler trials. Implementation would be monitored by NHS England, with public reporting of ICB-level performance.

Outcomes-based contracts, in which the manufacturer rebates the NHS if a biologic fails to reduce exacerbations by a pre-agreed threshold, could reduce financial risk for ICBs. Such contracts are already used in other therapeutic areas, such as gene therapies for spinal muscular atrophy. For asthma biologics, a simple contract could stipulate that if a patient does not achieve a 50% reduction in exacerbations at 12 months, the NHS pays a reduced price or receives a refund.

Transparency is another lever. NHS England already publishes some prescribing data at ICB level, but time-to-biologic metrics are not routinely reported. Mandatory publication of the median time from referral to first biologic dose, along with the proportion of eligible patients treated, would create accountability and allow patients and advocacy groups to identify underperforming ICBs. Similar public reporting in cardiac surgery led to rapid quality improvements.

Patient representation on ICB formulary committees is currently rare but could shift decisions toward clinical need rather than budget alone. The charity Asthma + Lung UK has called for at least one patient representative with lived experience of severe asthma to sit on every ICB's medicines management committee, with voting rights. In areas where this has been trialled, formulary decisions have become more aligned with patient priorities, such as reducing oral steroid exposure.

A patient story: Sarah's experience with delays

To illustrate the human impact, consider the case of Sarah, a 42-year-old teacher from a restrictive ICB in the Midlands. Sarah had been diagnosed with severe eosinophilic asthma at age 35, and despite high-dose inhaled corticosteroids and long-acting beta-agonists, she experienced four exacerbations requiring oral steroids in the year before referral. Her eosinophil count was 450 cells per microlitre, and her IgE was normal, making her an ideal candidate for an eosinophil-targeting biologic. However, her ICB's formulary required a three-month trial of omalizumab before considering benralizumab. During those three months, Sarah had two exacerbations, one requiring a five-day hospital admission. She gained 6 kg from oral steroids, developed steroid-induced diabetes, and missed 18 days of work. When she finally started benralizumab, her lung function had declined from 72% to 58% predicted. After six months on benralizumab, her exacerbation rate dropped to zero, and she was able to taper off oral steroids, but her lung function only partially recovered to 65% predicted. Sarah now advocates for policy change, speaking at NHS events about the need to eliminate step-therapy. Her story is not unique; patient support groups report hundreds of similar accounts.

The postcode lottery for biologic access in severe asthma is a failure of policy implementation, not of evidence. NICE has done its job; the hold-up is at the local level, where budget pressures and administrative inertia override clinical guidance. Other countries have shown that uniform access is achievable without bankrupting the system. The question is whether NHS England and its ICBs have the will to make equity a priority, or whether thousands of patients will continue to suffer preventable exacerbations and lung damage while the system dithers.

This article is for informational purposes only and does not constitute medical advice. Patients with severe asthma should discuss treatment options with their respiratory specialist.