U.K. team sheds light on how AnaptysBio's anti-IL-33 eczema drug tamps down inflammation

In a small trial, 83% of patients with eczema taking AnaptysBio's drug (Shutterstock) reported a reduction in symptoms.

In 2017, AnaptysBio raised $80 million in an initial public offering, then another $99 million in a private placement, in hopes of accelerating the development of its lead drug to treat eczema, the anti-interleukin-33 antibody ANB020, which had turned in promising data from a phase 2a trial.

Now a team of researchers in the U.K. has released more information from that trial—data the scientists gleaned from skin samples they collected so they could see exactly how targeting IL-33 relieves inflammation.

ANB020, now called etokimab, is currently in phase 2a testing in eczema, which is also known as atopic dermatitis. Scientists from the Medical Research Council Human Immunology Unit at the University of Oxford released data from 12 patients showing that 83% who were treated with etokimab reported a reduction in disease severity after 29 days.

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The patients also showed a 40% drop in immune cells called eosinophils, which are involved in allergic reactions. The research was published in the journal Science Translational Medicine.

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To examine exactly how etokimab works in the skin, the researchers first gave the 12 patients an injection of a placebo, followed by injections of dust mites. The next day, they collected fluid and cells at the injection site. A week later, they repeated the same experiment with AnaptysBio’s drug.

The team wanted to determine whether blocking IL-33, which is released by damaged skin cells, would change how immune cells that cause inflammation respond to allergens. After administering etokimab, the researchers observed that there were fewer of those cells, called neutrophils, moving towards the sites where the dust mites were injected.

It was “initially surprising to us that the dominant effect of etokimab was reducing neutrophil migration into the skin," said Graham Ogg, professor of dermatology, in a statement. "New antibody therapies, like etokimab, are exquisitely specific in what they target and they have the potential to help patients and to help us better understand disease."

The phase 2 trial of etokimab enrolled 300 patients with moderate to severe atopic dermatitis and was scheduled to be completed in September. The company has also launched a trial of the drug in chronic sinusitis.

Last September, AnaptysBio announced positive results from a phase 2a trial of etokimab in patients with severe eosinophilic asthma. In June of this year, the company followed up that data with additional results showing that a single dose of the drug produced improvements in lung functioning for 64 days or more. AnaptysBio plans to start a phase 2b trial in that indication this year.

AnaptysBio has long claimed to be the frontrunner in a race to get anti-IL-33 antibodies to market, but it does have some competition. Sanofi and Regeneron’s REGN3500 is also in phase 2 trials, and the companies recently announced the drug met its primary endpoint in a trial in asthma.

Still, all anti-IL-33 drugs will face tough competition in Dupixent, Sanofi and Regeneron’s IL-4 and IL-13-targeted hit drug to treat atopic dermatitis, asthma and sinusitis. In the recent trial of REGN3500, the drug appeared to be less effective than Dupixent, and there was no clear benefit in combining the two treatments.

As for the data from AnaptysBio, it has mostly come from small patient populations, and from trials that don’t pit etokimab against rivals like Dupixent. The company expects to release top-line data from the 300-patient trial of the drug this quarter.