Will we see gene therapy for eczema?

The European Commission is close to approving the first gene therapy in the Western world, according to the New York Times.

The treatment, called Glybera and developed by the Dutch company uniQure, treats a rare condition in which people are unable to break down fat-carrying molecules.

Gene therapy is one way that I imagine patients of the future might be cured of eczema. Glybera gives us a peek into how that might happen.

In gene therapy, doctors replace a patient’s faulty gene with a good one. The large protein filaggrin is currently the best candidate for eczema gene therapy. Several studies have linked filaggrin mutations to a higher risk of developing eczema.

Filaggrin gene therapy would have to be applied early in life. This is because in our current understanding, eczema is caused by a skin barrier defect that allows allergies to develop after a critical time window. Filaggrin mutations cause a faulty skin barrier. So you’d have to fix filaggrin early, because waiting too long would allow allergies to develop, after which fixing filaggrin solves only half the problem.

Glybera is a biotherapeutic, a gene (length of DNA) that is attached to a well-characterized and benign virus. Doctors will inject Glybera into leg muscles, where the virus infects cells and incorporates itself and the therapeutic gene into the patient's DNA—but only in leg muscle cells, presumably because Glybera gets absorbed locally. Then the patients will be able to break down the fat-carrying molecules, and their blood will no longer be overloaded with fat.

A biotherapeutic for eczema would likely be an intact filaggrin gene incorporated into a similar virus.

Gene therapy for the skin would have to be restricted to skin cells. You could accomplish this with a topical cream or ointment applied in the clinic. I'm guessing you would want to treat your whole skin, not just spots that were flaring up at the time.

How long will it last? The effects of Glybera apparently last for years, probably because muscle cells live a long time. Skin cells are a different matter—they are turning over continually. This could turn out to make gene therapy for skin conditions near-impossible.

But perhaps you could take regular doses—pills or injections—of a gene therapy that includes a genetic switch that turns on only in skin cells.

The critical early window for developing allergies in eczema patients could turn out to be a bonus in disguise. Maybe filaggrin gene therapy would only be required during a window of a few years, after which it could be discontinued and allergies would never develop.

Obviously extensive clinical trials for safety would be necessary. I could imagine this type of therapy becoming available within two decades. My grandchildren could be among the first to benefit.