(Bloomberg) -- Early fall is when asthma flare-ups peak in the US, and a warming climate is bad news for sufferers: It means more ground-level ozone, a longer pollen season and more wildfire smoke — all triggers for people with respiratory conditions.
While people with asthma or chronic obstructive pulmonary disease (COPD) can experience worse symptoms due to climate change, many of the medications they’re prescribed also contribute to warming by emitting potent greenhouse gases. Pharmaceutical companies are looking to change that with lower-emitting inhalers that they plan to roll out by the end of the decade.
Metered-dose inhalers — pressurized devices that release a puff of medicine into the mouth — make up the majority of the inhalers used in the US, according to data from 2019. They currently rely on hydrofluorocarbon (HFC) propellants. These chemicals, which are also used in air conditioning and refrigeration, are greenhouse gases far more powerful than carbon dioxide.
Inhalers account for around 0.03% of global greenhouse gas emissions. But in the US, where metered-dose inhalers dominate, their emissions alone in 2020 were equivalent to those from driving almost 600,000 gas cars for a year or burning over 2.7 billion pounds of coal.
“We’re trying to treat conditions like asthma and COPD with these inhalers, and we’re actually making it harder to breathe,” said Jyothi Tirumalasetty, a clinical assistant professor at the Stanford University School of Medicine.
Dry-powder inhalers — which a patient uses by sucking in a powdered medicine — and soft mist inhalers, which have a cartridge that releases a mist that is inhaled, have a far lower climate toll. A study that Tirumalasetty co-authored, published in August in the Journal of the American Medical Association, found these inhalers have a carbon footprint around 30 times smaller than that of metered-dose inhalers. Dry powder inhalers can be substituted for metered-dose types by a majority of patients but can also come at a higher price, and some people may lack the lung capacity to use them, or prefer metered-dose options. Those using a rescue inhaler during an asthma attack, especially, may want a propellant to help push the medicine into their airways.
This is why GSK Plc is focusing on lowering the emissions of propellant rescue inhalers, said Laura Clow, a medicine development leader at the company. GSK’s metered-dose Ventolin inhaler, prescribed to around 35 million people globally, accounts for 49% of the company’s entire carbon footprint.
GSK has entered phase three of trials for a new propellant for Ventolin. Currently each inhaler produces the equivalent of 24 kilograms of carbon emissions, but with the new propellant that will come down to 2 kilograms, Clow said.
The dose, look and feel of the new inhalers will be the same, she said, with only the propellant changing. Right now the new inhaler propellant costs more, but European Union fluorinated-gas (f-gas) regulations on HFCs are set to make the current propellant pricier too.
“With the introduction of the f-gas tariffs, the price of the current propellant is going to go up and will become more expensive than the new ones as we move forward over the next few years,” Clow said. “We haven’t fixed our pricing strategy yet, but our intent is that all patients will continue to have full access to that salbutamol inhaler.”
GSK expects to submit regulatory filings for the updated inhaler in 2025 and to complete a full transition to the new propellant by 2030.
AstraZeneca Plc recently completed the studies and clinical program for a propellant with 99.9% lower emissions for its COPD metered-dose maintenance inhaler, Breztri. The company plans to file for regulatory approval in the UK, Europe and China by the end of 2024, and then file in other countries in 2025.
Pablo Panella, senior vice president of global respiratory at AstraZeneca, said that it took years for the company to find a replacement for the propellant that would still allow patients to use their medication in the same way.
Developing “a safe, environmentally-friendly and manufacturable propellant is not easy. There is a very substantial amount of investment that comes with this,” he said.
Panella said the company has invested over $400 million into transitioning its inhalers to be less emitting, but it does not necessarily expect this to translate into higher costs for patients. He said AstraZeneca is also looking to transition its other metered-dose inhaler propellants as it aims to cut Scope 3 emissions in half by 2030 compared to 2019.
GSK brought in £749 million ($1 billion) in revenue from Ventolin in 2023, and AstraZeneca had $677 million in revenue from Breztri last year.
Albert Rizzo, chief medical officer at the American Lung Association, said that the association is in favor of seeing the current propellants phased out but has concerns about insurance coverage and a lack of generics available during the transition process, which can impact patients’ access to care in the US.
“We don’t want them to lead to increased costs, and this is something that can occur over the course of the next several years,” Rizzo said. “It’s not going to happen tomorrow or next year, but it’s going to as these drugs are phased out.”
Another problem is the waste generated after inhalers of all types are used. Recycling them can allow for the reuse of some of the metals they contain and for the storage of their propellant gases so these are not released into the atmosphere.
But there are few options for patients to recycle inhalers. Cities typically don’t accept them in normal recycling bins because of the chemicals and pressurized gas, which can pose risks. Some pharmacies in the US and UK will take back used inhalers, but the inhalers may be disposed of rather than recycled.
GSK previously had a scheme for recycling inhalers at pharmacies in the US, UK and several other countries, but the company ended it in 2020. Clow said scaling up inhaler recycling would require an industry-wide effort.
Whatever kinds of inhalers are used, when people can keep their respiratory condition under control, it means there’s less need for emergency interventions. That’s helped by early detection, affordable drug prices and governments working to reduce air pollution and wildfires, Rizzo said.
“Those of us who have underlying lung conditions are going to have more flare-ups due to those climate change effects in the air quality,” he said. “More flare-ups means more cost to the healthcare industry, more hospitalizations and poor quality of life for these individuals.”
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