CHICAGO –
There are a number of clinical trials underway, including one for the investigational drug TPM502, which carries three gluten-specific antigenic peptides with overlapping T-cell epitopes for the HLA-DQ2.5 gene. And, research is underway for the novel KAN-101, which aims to restore the immune tolerance of gluten by targeting receptors on the liver. It received Fast Track designation by the Food and Drug Administration in 2022.
During the annual Digestive Disease Week® (DDW), researchers shared the results from a new proof-of-concept study for DONQ52, a bispecific antibody that targets HLA-DQ2.5. DONQ52 was found to be highly effective in blocking gluten-specific T cells, said investigator Jason A. Tye-Din, PhD, a researcher with The Walter and Eliza Hall Institute of Medical Research, Melbourne, and an investigator with Chugai Pharmaceutical, which is funding the DONQ52 research which has since advanced to a phase 1 study of 56 patients.
There are no existing drug therapies for celiac disease, which leaves patients with a lifelong, and strict, gluten-free diet as treatment. This strategy, however, often fails to induce mucosal healing or symptom control, and has stimulated a search for novel therapies, said Melinda Y. Hardy, PhD, a postdoctoral researcher with the University of Melbourne, and the first author of the DONQ52 study. While targeting the gluten-specific immune response is highly attractive, it presents safety and pharmacokinetic challenges, so a better alternative would be to develop antibodies that selectively bind to HLA-DQ2.5, which is found in 80%-90% of celiac disease patients, she said. DONQ52 blocks at least 25 gluten peptides, and binds specifically to complexes of HLA-DQ2.5 and a range of immunogenic gluten peptides.
The study included 20 patients who consumed wheat bread for 3 days. Blood samples were taken 1 day before the start of the trial and 6 days after it concluded. Twenty patients were found to be wheat challenged, 10 were barley challenged, and 14 were rye challenged.
All were tested for gluten-specific T-cell responses in the presence or absence of DONQ52, which was designed to reduce the wheat-specific T-cell response because 90% of gluten intake is from wheat. “If you have celiac disease, you have a reservoir of these gluten-specific T cells. When you eat gluten, they’ll be activated and switched on and that’s what we want to block,” Dr. Tye-Din said.
The main assessment – a day 6 wheat challenge among 15 responders – revealed a more than 80% reduction in T-cell responses to a peptide cocktail. DONQ52 also reduced barley and rye T cell responses in a day 6 challenge, although to a lesser degree (40%/80%).
“DONQ52 is designed to target individual peptides that trigger the disease, and we showed that it did it very well to the wheat peptides, well over 80%. That’s a very impressive reduction in responses,” he said. A further test among 20 samples showed that DONQ52 did not activate T-cells nonspecifically. “You don’t want to trigger an unnecessary response,” Dr. Tye-Din added.
“DONQ52 effectively reduces activation of wheat gluten-specific T cells. It also has broad reactivity extending to barley and rye T-cell epitopes,” said Dr. Hardy.
The study was funded by Chugai Pharmaceutical. Dr. Hardy is a coinventor on a provisional patent describing oats peptides in celiac disease therapeutics and diagnostics. Dr. Tye-Din disclosed associations with Chugai, Genentech, Janssen, and Takeda, among others.
DDW is sponsored by the American Association for the Study of Liver Diseases, the American Gastroenterological Association, the American Society for Gastrointestinal Endoscopy, and The Society for Surgery of the Alimentary Tract.