Don’t hold your breath

The story at the Herald (from the Telegraph) starts off dramatically, then walks its claims back, but not back far enough.

First off, the dramatic claim:

Asthma could be cured within five years after scientists discovered what causes the condition and how to switch it off.

Then the description of what the researchers actually did: ‘identified which cells cause the airways to narrow when triggered by irritants like pollution.’ That’s less dramatic; it’s also not true. The researchers looked at the same cells everyone else looks at. What they did was show that a molecule on the surface of these cells (“calcium-sensing receptor”) appears to be central to the triggering.

The other main selling point:

Crucially, drugs already exist which can deactivate the cells. They are known as calcilytics and are used to treat people with osteoporosis.

In fact, they aren’t used to treat people with osteoporosis. As the research paper says, they “were initially developed as anti-osteoporotic drugs and reached phase 2 clinical trials for this purpose”. That is, they didn’t work. They might work for asthma, but it’s not like finding a new use for an actually-marketed drug — especially as the drugs would have to be inhaled, something that hasn’t been studied in humans at all. If everything goes right, it might be possible to get the safety and effectiveness studies done and the drug approved in five years, but that’s pretty optimistic.

Also, the drugs are promising, but not as promising as the story says:

But when calcilytic drugs are inhaled, it deactivates the cells and stops all symptoms.

Most of the research was either in isolated cells (which don’t have symptoms) or in non-asthmatic mice. One experiment, in asthmatic mice, showed a reduction in airway resistance with the drugs, but not down to the level in non-asthmatic mice.  And airway resistance isn’t the same as symptoms. And these are mice.

A comment from Asthma UK raises another point that hasn’t appeared so far

“Five per cent of people with asthma don’t respond to current treatments so research breakthroughs could be life changing for hundreds of thousands of people. If this research proves successful we may be just a few years away from a new treatment for asthma”

Inhaled steroids for asthma are already pretty effective. While they aren’t enough for everyone, a more common problem is the hassle of using the inhaler twice a day every day when you’re healthy, to prevent relatively rare asthma attacks.  The new drugs will likely have the same problem  — it’s a treatment, not a cure — and their real potential isn’t for everyone with asthma, but for the relatively small subset where current treatments don’t work.