Colonoscopy Dye Tablets Boost Polyp Detection Rate

Ingestion of the delayed-release methylene blue dye (MMX) tablet during bowel preparation for colonoscopy increases adenoma detection rate (ADR), claims a new study.

Researchers at Humanitas University Medical School (Milan, Italy), Mayo Clinic Florida (Jacksonville, USA), and other institutions conducted a study involving 1,205 patients scheduled for colonoscopy at 20 centers worldwide, randomly assigning patients to one of three groups: Those who received a full dose of oral MMX during colonoscopy preparation; patients who received a placebo during preparation; and a group of patients who received a half dose of MMX. The third group was used to make it harder for participating physicians to know which patients were in the active group.

The results revealed that patients who received the full 200 mg dose of MMX had 56.3% detection rate of adenomas and carcinomas; in the placebo group, the detection rate was 47.8%. Flatter and smaller lesions--less than 5 millimeters in diameter--were found in patients who received the full dose of MMX. When excluding the expected effects of blue feces and urine discoloration, less than 6% of the patients experienced other mild adverse effects when taking the tablet. The study was presented at the annual Digestive Disease Week (DDW), held during June 2018 in Washington (DC, USA).

“Identification of cancerous and pre-cancerous lesions is of utmost importance to prevent colorectal cancer,” said lead author and study presenter professor of gastroenterology Alessandro Repici, MD, of Humanitas University Medical School. “Our study, which used the highest standard of care, allowed gastroenterologists to better detect and remove difficult-to-see polyps, which has great implications for further preventing this disease.”

“While utilizing blue dye to increase ADR is not a new concept, the fact that this technology now comes in tablet form is a major advance,” said senior author Professor Michael Wallace, MD, MPH, of Mayo Clinic Florida, and a primary investigator on the Phase III trial of MMX. “Our research shows the oral delayed-release methylene blue provides gastroenterologists with a new means to improve their ADR, with no additional inconvenience or safety risks to the patient and no supplemental time required to the endoscopist.”

Methylene blue is both a medication and a dye. As a medication, it is used to treat methemoglobin levels greater than 30% or in which there are symptoms despite oxygen therapy. Methylene blue is also used as a thiazine dye, which works by converting the ferric iron in hemoglobin to ferrous iron. While usually given in injected form, the tablet form, MMX, is under development by Cosmo Pharmaceuticals (Dublin, Ireland; www.cosmopharma.com). The tablets are coated with pH-resistant acrylic copolymers, which delay the release until the tablet reaches the indicated intestinal location where the programmed dissolution begins.

Related Links:
Humanitas University Medical School
Mayo Clinic Florida