A tiny tissue tear has gotten in the way of the careers of former New York Knicks point guard Jeremy Lin and English Premier League soccer star Michael Essien. The same injury also routinely ruins the fun of millions of weekend warriors. Now a new technology using pig tissue may save those careers and undo the painful damage from torn meniscus in knees.
The removal of damaged meniscus tissue is the most common orthopedic procedure in the U.S. and is a major cause of osteoarthritis. While replacing damaged meniscus with donor tissue helps reduce pain and restore normal range of motion, a shortage of donors has limited the scope of such operations. That may soon change. Tissue Regenix Group Plc of York, England, is developing a new product using material from pigs that holds the hope of producing abundant quantities of tissue.
“A product that restores normal function of the meniscus and prevents or delays development of arthritis would have huge demand,” said Marc Galloway, an orthopedist in Cincinnati and a spokesman for the American Academy of Orthopaedic Surgeons who isn’t involved in Tissue Regenix’s research.
The menisci are made of C-shaped cartilage that serve as shock absorbers for the knees. Currently, tears are treated through surgical repairs with stitches, a fifth of which fail, or partial removal of damaged portions. The market for these procedures is about $3 billion, according to Peel Hunt LLP.
Tissue Regenix’s dCELL technology involves taking animal tissue and removing cellular material from it that would cause humans to reject the implant. That allows doctors to use the stripped tissue without anti-rejection drugs to replace worn out or diseased body parts. Once implanted, the cellular scaffold is repopulated with the patient’s own stem cells.
This decellularization technology may also potentially be applied to heart valves and wound care. Tissue Regenix received European approval in August 2010 for its first product, a vascular patch, which replaces tissue removed during open-heart surgery, and the company is in the process of obtaining U.S. clearance.
Data from a pre-clinical trial for the meniscus application will be released this year, with a trial in humans to start in 2013, Chief Executive Officer Antony Odell said in a phone interview. The company may file for approval as early as 2014, he said.
A recent study at Yale University showed that Tissue Regenix’s dCELL scaffold in vascular patches led to much quicker cell re-population after one week, compared with a limited effect after one month for a competing product using cow tissue from Synovis Life Technologies Inc., which was acquired by Baxter International Inc. in February.
“This study shows that after the dCELL process, the stripped tissue is so similar to human tissue that the body accepts it more rapidly than conventional patches,” said Alan Dardik, an associate professor of surgery at Yale who led the study published in the journal PLoS One in June. “It appears to be a new breakthrough in acute healing,” added Dardik, who has no financial interest in the company. “It might be a very useful replacement in the meniscus area as well.”
Currently, no tissue engineering companies have commercialized an orthopedic product, according to Paul Cuddon, a London-based analyst at Peel Hunt LLP, Tissue Regenix’s investment banker. “It’s a totally unique product in its field,” he said.
The technique, if proven to work, could reduce demand for knee replacements by reducing cases of severe arthritis. That would threaten the growing $7 billion prosthetic knee industry, prompting device makers such as Smith & Nephew Plc or Johnson & Johnson to consider acquiring Tissue Regenix as a hedge, said Ingeborg Oie, a Jefferies International Inc. analyst in London who follows medical device makers.
The company may also attract bidders or licensing agreements for the technology’s other applications based on pending clinical study results, Cuddon said. Given the growing market for heart valves, Edwards Lifesciences Corp., Medtronic Inc., St. Jude Medical Inc. and Johnson & Johnson may take an interest, he said.
“They are all major heart-valve players that could do with better decellularization technology,” he said.
Tissue Regenix issued shares in June 2010 at 5 pence each after a reverse takeover of Oxeco. The shares traded at 9.13 pence as of 3:05 p.m. in London.
For weekend athletes with knee injuries, tissue transplant procedures can’t arrive soon enough. Erin Hallock had four stitches sewn into her meniscus to repair a tear after a fall while skiing on icy slopes in Zermatt, Switzerland in March 2010. Two years later, Hallock, 35, is able to ski and cycle, but she worries how long the repair work will last and one important challenge remains completely out of her grasp: long-distance running. “My doctor said, ‘You can’t run a marathon anymore,’” she said.
For professional athletes, of course, the consequences of such injuries can be even more devastating. A torn meniscus forced Lin into surgery in April and has taken Los Angeles Clippers forward Blake Griffin off the U.S. Olympic basketball team. Essien, the Chelsea player, injured his anterior cruciate ligament along with his meniscus last year, keeping him off the field for six months.
While calcium build-up, which hardens the donor tissue, is a drawback of decellularization technology developed by others, Tissue Regenix has found an alternative solution. Instead of using the disinfectant glutaraldehyde favored by competitors, the company has chosen to use sodium dodecyl sulphate, an approach that doesn’t lead to calcium build-up, Cuddon said.
The timeline for obtaining approval from the Food and Drug Administration is unclear. The FDA requires more clinical analysis for non-pharmaceutical medical devices than European regulators. And tissue products like those derived from dCELL’s scaffold are categorized as medical devices since they are implanted and not metabolized by the body.
Erica Jefferson, a spokeswoman for the FDA, declined to comment on the approval prospects for Tissue Regenix’s products.
Still, researchers remain hopeful. Given the acceptance of porcine tissue by the medical community, especially in heart valves, safety isn’t a concern, Yale’s Dardik said.
“It’s extremely similar to human tissue and is implanted thousands of times every day across the world,” he said. “In the future, there will probably be pig organ transplants. That’s the holy grail of transplant surgery.”