Sunnybrook’s Dr. Bradley Strauss is about to launch the world’s first large-scale clinical trial for a revolutionary investigational drug. Collagenase, or MZ-004, promises to soften complete arterial blockages so that angioplasty procedures can be used to successfully restore blood flow, eliminating the need for bypass operations.
“This is pure pioneering work. We are excited about the success of our first group of patients in the proof-of-concept study. They experienced an almost immediate relief of symptoms and a significant improvement in their quality of life,” says Dr. Strauss, chief of the Schulich Heart Program. The study was published in the journal Circulation and was funded by the Canadian Institutes of Health Research and the Heart and Stroke Foundation of Canada.
An angioplasty procedure involves advancing a small guide wire, less than a hair’s width in diameter, through the narrowed space in an artery. A small balloon is inflated to restore blood flow and a stent put in place to hold the artery open.
But angioplasty doesn’t work for all patients: About 20 per cent of patients having an angiogram are diagnosed with chronic total occlusions, blockages made of hardened collagen that are impossible to thread past. For those who have chest pain and difficulty breathing, their only other options are bypass operations or medications.
To solve the problem, Dr. Strauss developed collagenase over a period of 10 years. Drip by drip, the innovative agent is injected into the hard blockage to soften it so that an angioplasty can be successfully performed 24 hours later. Findings from the proof-of-concept study found that 15 of 20 patients with chronic total occlusions, or 75 per cent, had successful angioplasties after collagenase treatment, despite previous failed attempts.
“For patients, this treatment makes a huge difference. For example, one patient in his early 50s had already had multiple bypasses and suffered from angina or chest pain for a year. They tried to do angioplasties in London but failed because he was a very challenging case. We were able to treat him with collagenase. The next morning, he told me it was the first night he’d slept in a year. It’s humbling and very gratifying to see that something you worked on makes such a difference in someone’s life,” says Dr. Strauss.
Led by Dr. Strauss and his team at Sunnybrook, the large-scale clinical trial will start this fall, pending final acceptance by Health Canada and the FDA. The study will test the effectiveness of collagenase compared to a placebo among 450 patients, with half of the major test sites in Canada and half in the United States.