By Amy Ratner, Beyond Celiac Medical and Science News Analyst

Researchers working on a vaccine to protect celiac disease patients from gluten exposure got a better idea in a recent clinical trial of the doses that will be needed, clearing the way for the drug to move to the next stage of study.

ImmusanT, a Massachusetts biotechnology company developing Nexvax2®, reported that a just-concluded Phase 1b trial tested the safety and tolerability of the therapeutic vaccine at various doses, from an initial injection through a series of booster shots.

Nexvax2 is a form of immunotherapy, a promising approach to celiac disease that uses the body’s own immune system to treat or prevent disease.

Building resistance

The premise behind Nexvax2 is that if a small amount of the vaccine is given at first and the amount gradually increased, the immune system of those who have celiac disease and the gene most commonly associated with it, HLA-DQ2.5, will build up resistance to the harmful protein in gluten without any negative effects.

In the recent clinical trial, 38 patients in three groups were given gradually escalating doses of the vaccine or a placebo, followed by maintenance doses that were higher than those tested in earlier studies. Results are being used to create a dosing regimen for a planned Phase 2 study this year.

A Phase 2 study is an important next step that will involve more participants and be designed to determine how well the vaccine works at protecting against gluten exposure and whether the benefits outweigh any risks. ImmusanT will begin recruiting patients later in 2017. Sixty three percent of drugs make it to Phase 2 trials, according the Biotechnology Innovation Organization, a trade association.

Initially, the vaccine would be used to protect against gluten exposure while patients continue a gluten-free diet. But as a second step, ImmusanT is looking to launch a vaccine that would eliminate the need for the diet.

New class of drug

Nexvax2 contains three peptides, the small segments of the larger gluten protein. These peptides cause the T-cell reaction in celiac disease that results in symptoms and intestinal damage. T-cells are white blood cells that function as the body’s disease fighting soldiers. In the case of celiac disease, they are incorrectly turned on to attack when the gluten peptides are detected.

Results of this fourth clinical study of the vaccine “provide important insights into the optimization of dosing and immune monitoring for this new class of drug,” the company said in a press release announcing its conclusion.

“Nexvax2 has the potential to protect against the effects of gluten exposure in patients with celiac disease and improve their quality of life,” said Leslie Williams, ImmusanT president and chief executive officer.

Previous studies have shown that the first dose of the vaccine prompted the immune reaction to gluten, with patients who received Nexvax2 showing activation of T-cells as well as typical celiac disease symptoms. But when the treatment ended after twice weekly doses of Nexvax2 for eight weeks, the T-cells were no longer active. Additionally, when patients who had received Nexvax2 ate gluten for three days, the immune reaction was not triggered.

Nexvax2 is one of several celiac disease drugs being studied in light of evidence that patients on the gluten-free diet continue to have symptoms, intestinal damage or both, and other ongoing research that highlights the significant burden of the diet in general.

Read more about Nexvax2 here.

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