Tuesday, 14 October 2014

Omalizumab: a New Treatment Option for Allergic Bronchopulmonary Aspergillosis (ABPA)

ABPA is an allergic infection of the airways. It is not yet clear why some people get ABPA while most of us do not as the infecting mould is inhaled by nearly all of us on a daily basis. For most of us this is not a problem as our lungs are lined with protective immune cells that destroy the mould before its can establish itself, but for those rare few with ABPA this did not happen and the mould (Aspergillus) persisted and grew to block airways and cause inflammation. It rarely invades anything but the air spaces, it does not invade our lung tissues but does cause a lot of irritation and breathing problems that cannot be cured. This is a long term seriously debilitating condition.

One population we know is particularly vulnerable to ABPA is those people with cystic fibrosis (CF). Figures vary but something like 10 - 25% of people with CF get ABPA. Perhaps that is not surprising as their lungs are prone to infections as they cannot properly rid themselves of infectious particles including mould spores. Someone with CF already has severe problems breathing without suffering from contributing infections and some figures suggest 50% of all people living with CF have some form of infection by Aspergillus - not all are thought to progress to ABPA.

Treatment for ABPA is to use steroids to control inflammation and often an antifungal drug which can allow the dose of the steroid medication to be minimised, thus helping to avoid some of the many unpleasant side effects of taking high dose corticosteroids. This doesn't work for everyone and alternatives are being actively sought.

Originally developed for severe asthmatics, Omalizumab (Xolair) directly targets the parts of our immune system that leads to excessive inflammation. In asthmatics this has been demonstrated to lessen symptoms and has benefited patients. Many CF patients and those with ABPA are also asthmatic. ABPA is known to cause chronic airway inflammation and so ABPA patients are a candidate for use of this drug.

Some of the toughest patients to treat are probably those with CF and ABPA and we now have the first reports of patients from those groups who are being treated with Omalizumab. The most recent paper by Lehman et. al. looks at a small number of patients (6) with wide age range (age 4 - 33) treated over 7 years and suggested that Omalizumab was beneficial especially in those who had less progressed disease with benefits of taking lass corticosteroid also apparent.

This result offers hope for alternative treatment to ABPA patients who do not have CF,

1 comment:

Anonymous said...

This drug is very,very expensive & thus going to be out of reach for the average person. Also: 6 patients is not nearly enough of a test group to come to any significant conclusions. It does offer hope & I guess that's worth something.

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