Asthma Trials

Asthma - current research

Several research studies are currently underway to find out if omalizumab (oma-liz-oo-mab; Xolair™) is safe and effective in asthmatics. Omalizumab is a manufactured antibody that inactivates one of the key players in the the inflammatory process: a protein called IgE.(1) Although the animal studies suggest that this drug should be effective in asthma, relatively little is currently known about its effect on asthma in humans.

An interesting new idea in the treatment of asthma is to eradicate any low-grade infections in the lungs that may be causing the asthma symptoms. The researchers behind this study state that around half of all cases of asthma in adults may be caused by persistent, long-term infections. They have designed a trial of a commonly-used antibiotic, azithromycin, given in a once-weekly dose for 12 weeks. They anticipate that some patients may continue to benefit for up to a year after this treatment. Another trial of a different antibiotic, clarithromycin, is also underway.

A well-established treatment for chronic bronchitis, tiotropium (Spiriva™) is being tried in asthmatics in the hope that it will reduce their symptoms and prevent them from needing steroids.

One trial aims to prevent asthma from ever developing in a group of children by giving their mothers a probiotic, like the yoghurts that are currently a diet fad in much of the western world. The pregnant mothers will consume the probiotic (a lactobacillus) during the second trimester of pregnancy, and then the infants will be given the treatment for six months after birth. The plan is to follow the infants for many years to find out how many of them develop asthma, hay fever and eczema.

Asthma - future treatments

A cocktail of Chinese herbal remedies has been suggested to have a range of anti-inflammatory effects and is currently under trial. The initial trials are designed to show that the herbs are safe in humans, before a larger trial is carried out to determine if the cocktail really is an effective treatment for asthma. The team behind the trial report that the herbs, Ling Zhi, Ku SHen and Gan Cao, have been shown in preliminary studies in China to be an effective alternative to prednisone (prednisolone; a steroid tablet) for treating asthma.

Another trial proposes to use lovastatin, a widely-used cholesterol-lowering drug, to treat asthma. This doesn’t initially seem to make much sense, but when you consider that this group of drugs (the statins) has a broad anti-inflammatory effect,(2) it is easier to imagine how they might help treat asthma. The trial is expected to take several years to determine if lovastatin can in fact improve symptoms of asthma: the expected completion date is 2012.

A clinical trial of the combination of two therapies, montelukast and fish oil, aims to find out if the addition of fish oil supplements to montelukast (already a standard treatment for asthma) has an additional effect in suppressing inflammation in the airways. Previous work has claimed that fish oil supplementation reduces the wheeze that some asthmatics experience when they exercise.

One of the more unusual treatments currently proposed is cockroach extract, administered under the tongue. The study is recruiting people who are known to have allergies to cockroaches. The idea is that the immune system can be re-trained not to respond to the cockroach with an allergic reaction – a principle called immunotherapy. Another trial is investigating whether a treatment that mimics the allergy-causing substance released by cats can be used in a similar way. Using this new treatment, asthma sufferers will be “vaccinated” against cats.

References

(1) Hanania NA. Targeting airway inflammation in asthma: current and future therapies. Chest 2008; 133(4):989-998.

(2) Schonbeck U, Libby P. Inflammation, immunity, and HMG-CoA reductase inhibitors: statins as antiinflammatory agents? Circulation 2004; 109(21 Suppl 1):II18-II26.

Author: Kenneth Baillie

Reviewers: Roger Thompson, Paul Brennan

Updated: January 09 2009.