Protalix BioTherapeutics’ ulcerative colitis therapy OPRX-106 eradicated the disease in a third of the first 14 patients participating in a Phase 2 clinical trial.
Fifty-seven percent of the patients responded to the treatment in some way, Protalix added.
Although scientists have made major advances in ulcerative colitis treatment, there is no cure for the inflammatory bowel disease.
Ulcerative colitis is an autoimmune disease, or one in which the immune system attacks healthy tissue. A cell signaling protein called tumor necrosis factor, which regulates immune cells, plays a key role in the inflammation involved in the disease.
OPRX-106 targets tumor necrosis factor, or TNF. It is a fusion protein, or one made up of parts of two proteins fused together. In this case, the components are TNF receptor II and IgG1 Fc.
An unusual feature of OPRX-106 is that it is delivered to the gut in a plant cell. The cell’s cellulose wall prevents the treatment from disintegrating in the digestive tract.
OPRX-106 is an oral alternative to injected therapies that target TNF. Injected versions can have non-gut-related side effects and generate antibodies that reduce the drug’s punch.
By delivering a treatment directly to the gut, an oral version avoids these problems. In addition, it is more convenient for patients than injections.
Studies in mice indicating that OPRX-106 could alleviate bowel disease led to a Phase 1 clinical trial of the therapy in healthy volunteers (NCT02107833).
The goals of the Phase 2 trial (NCT02768974) were to evaluate OPRX-106’s safety and effectiveness in people with mild to moderate ulcerative colitis. The 24 patients received one of two doses for eight weeks.
Fifity-seven percent of the first 14 patients to complete the study responded to the treatment, and 36 percent achieved remission.
Seventy-nine percent had far less rectal bleeding than before their treatment, and 86 achieved a reduction in a biomarker of intestinal inflammation known as fecal calprotectin.
Another good sign was that 64 percent of the patients had better Geboes scores after treatment. The Geboes index assesses ulcerative colitis activity in the gut.
An important safety finding was that patients tolerated OPRX-106 well. Most adverse events were mild to moderate, with the most common problem being headaches.
“Orally administered OPRX-106 is a tremendous step forward,” Dr. Yaron Ilan, a professor at Hadassah Hebrew University Medical Center in Jerusalem, said in a press release. It has the potential to “significantly lower side effects as it does not suppress the immune system while redirecting it in an anti-inflammatory direction.”
This makes it different from “the currently approved anti-TNF treatments, all of which are administered via injection or infusion, and carry potential short and long term side effects,” added Ilan, the lead investigator of the trial.
“We are very excited by these first-in-patient results, which demonstrate that novel, orally administered OPRX-106 treatment is biologically active in the gut with clear clinical effect,” said Moshe Manor, Protalix’s President and CEO.
Results of the full study are expected by the end of the first quarter of 2018.