Vaccine to treat celiac disease clears first stages of clinical trials



immusant-logoFor a number of years, an American company called ImmusanT has been working on a potential vaccine to protect celiac sufferers from the effects of exposure to gluten and the gastrointestinal symptoms that can result such as diarrhea, abdominal pain and bloating.

The Massachusetts biotech firm says it has completed its first phase 1b trial of Nexvax2.

As many of us are aware, celiac disease is remarkable among chronic diseases in that it is very common but has no proven, approved treatment beyond dietary restriction. It affects around 1% of people – though an estimated 90% remain undiagnosed. In most celiac cases, the disease is thought to be caused by a mutation in the HLA-DQ2 gene, which is involved in immune regulation.

Developing effective treatments is important as, despite being on the gluten-free diet, around a third of people with celiac disease still suffer from symptoms as well as damage to the cells lining the intestines – often without even realizing it.

This is rather complex, but ImmusanT’s big idea is to use three “peptides” (an amino acid-containing compound within our bodies) as an immunotherapy that it hopes will encourage the T cells involved in the inflammatory reaction in celiac disease to become tolerant to gluten. After a first course of the vaccine, to induce tolerance, the company hopes that this tolerance can be maintained by periodic re-injection with the vaccine.

It’s a case of “so far, so good”, with the phase 1b trial in 38 patients revealing no concerns about safety or tolerability and showing that the immunotherapy seemed to have the desired effects on the immune system.

The study also allowed ImmusanT to select a dosing regimen for planned phase 2 trials that will see if Nexvax2 can be used alongside a gluten-free diet to protect patients when they are accidentally exposed to gluten, which ImmusanT sees as the quickest route to approval in the United States.

Depending on the results, a follow-up program is planned that will focus on an immunotherapy that could do away with the need for the gluten-free diet entirely. The company is also developing a companion diagnostic for the vaccine which could guide its use and help improve diagnosis rates.


Treatments Under Development For Celiac Disease

L.A. Times reporter Cathryn Delude has written a great summary article of the efforts underway to develop treatments for Celiac Disease. You can find the full article in the December 21st edition called “New hope for Celiac Disease“.

She writes that there are two categories of treatments being developed:

1. Enzyme therapy, that would supplement a gluten-free diet and protect patients from occasional gluten exposure, and;

2. Immunotherapy, that would train the immune system to tolerate gluten and allow one to eat a regular diet.

Here’s a quick summary of the article.

Enzyme therapy uses oral enzymes that target gluten. Humans cannot completely digest gluten as we lack the digestive enzymes to break it down. Stanford researchers are combining enzymes from bacteria and barley to finish this digestion. Tests in rats proved to be promising. Alvine Pharmaceuticals is now recruiting patients for a Phase II clinical trial. Phase II trial testing of a different enzyme therapy drug, Larazotide, by Alba Therapeutics, is almost complete.

Immunotherapy is proported to allow Celiacs to eat a regular diet by quelling T-cell immune response. A company, Nexpep, is packaging the gluten peptides that trigger the immune response in a vaccine delivered under the skin to desensitize the immune reaction. Testing is said to have worked well in animals. Phase I safety trials of the vaccine, Nexvax2, will be completed in mid-2010.

Some of you may have also heard of the hook worm approach. This is where a hookworm is put in the gut to relieve asthma. Researchers have now tested it on 20 patients with celiac disease to see if they have benefits from it as a low-tech immunotherapy. The results haven’t been published but all the patients in the trial refused medication that would kill the parasites after the trial was complete.