No DBM? No Allograft? No Bone Void Fill of any kind? Talk about flying without a parachute, or driving without a seat belt.
But that is precisely the conclusion that came from a short press release issued earlier this year by Salt Lake City-based Amedica Corporation. The data was from a prospective randomized study of silicon-nitride interbody spacers.
The magic, apparently, comes from silicon-nitride. The study, called CASCADE, showed that composite interbody spacers using two different formulations of silicon nitride ceramic, i.e., a solid phase cortical portion surrounding a structured cancellous ceramic core, had equivalent fusion results to a PEEK spacer with autogenous bone graft.
No DBM, allograft, synthetic fillers or biologics. Just a spacer.
The CASCADE Study
The CASCADE study, which was a blinded, randomized clinical trial that compared outcomes of spinal fusion surgery between Amedica’s composite silicon nitride spacers manufactured with a central core of cancellous structured ceramic (CsC), to PEEK (polyether ether ketone plastic) spacers filled with bone autograft.
The investigators enrolled 104 patients and the fusion scores, which were independently scored, were compiled at 12 months follow-up.
The study conclusions were: Neck Disability Index scores decreased similarly in both the treated group and the control group and was consistent with clinical improvements reported in the literature. Importantly, the incidence of cervical spine fusion was statistically identical between the treatment group and the control group—and consistent with figures reported in other studies.
The lead investigator for the study, Mark P. Arts M.D., Ph.D., Neurosurgeon at the Medical Center Haaglanden, The Hague, Netherlands said of the results; “Surgeons have long known that autograft is the holy grail of bone healing. All osteoinductive and osteoconductive formulations on the market today aspire to show healing rates that are comparable to autograft bone. Hollow-body PEEK spacers used in cervical and lumbar spinal fusion must be filled with osteoconductive materials, such as allograft, bone autograft, or synthetic biologic formulations. The CASCADE study is the first to show that a synthetic material can heal and fuse as well as the patient’s own bone. We have shown that it is no longer necessary to use hollow interbody spacers filled with bone or bone void fillers to achieve optimal fusion results.” (emphasis added)
Long and Difficult Road
The news comes at a critical time for Amedica. The company, which is public, has struggled since its IPO in 2014. Its market capitalization sits at just $11 million. And the company has struggled for visibility in the crowded U.S. interbody fusion segment.
The CASCADE study results, which were announced in January 2015, may well have put Amedica at an inflection point.
Over the years Amedica has raised and spent well over $100 million to, among other things, build a state-of-the-art ceramics manufacturing facility in Salt Lake City. Sales are starting to pick up. But, aside from one intrepid Wall Street analyst (and former orthopedic industry executive), almost no one is paying attention to Amedica’s clinical data.
In October 2014 Amedica’s board brought in Sonny Bal, M.D., J.D., M.B.A., to take on the CEO and Chairman duties.
Since arriving at the company, Dr. Bal instituted a nearly-40% headcount reduction and sharpening the company’s focus to OEM and other partnerships, which can augment its retail spine business and develop a variety of new products targeted at the sports, extremity, and total joint lines. “We are focused on leveraging our unparalleled expertise and depth of science in silicon nitride to develop products that simplify surgery, and address clinical concerns related to the limitations of legacy materials, such as metal and plastic that have been with us since the 1960’s. A new generation of patients will demand biomaterials with extreme performance, durability, and biocompatibility. We are ideally positioned to meet that need.”
Speaking From the Head and Heart
Dr. Bal is a long-time investor, board member and silicon nitride researcher and a true believer and enthusiast for the technology, so he is speaking from both the head and heart. “Silicon nitride was developed for demanding industrial applications, such as aircraft bearings, internal combustion engine and turbine components, and space technologies. Its biomedical applications are facilitated by the facile nature of the material, “he says. “’As fired’ (solid) silicon nitride facilitates bone ongrowth. Polished silicon nitride is ideal for orthopedic bearings and in fact has demonstrated less wear and better toughness than existing ceramic total joint components. Indeed, the space shuttle engines rely on similar bearings to improve their reliability. Porous silicon nitride encourages bone ingrowth without biologic additives. All formulations show anti-bacterial behavior, and these material properties reflect a ‘living’, bioactive surface that is complex and interesting from a biologic and engineering standpoint, ” said Dr. Bal.
Dr. Bal is Professor of Orthopedics at University of Missouri, a well-known and published U.S. implant surgeon, and an attorney focused on medico-legal education; positions he has put on the back burner to guide Amedica in its quest to prove silicon nitride as the optimal material for interbody spacers.
Amedica’s DNA is as a biomaterials company. And its silicon nitride spacers are arguably the best, state-of-the-art biomaterial for a variety of orthopedic implants. Enough money has been sunk into the company, they should be.
Spine and Large Joints
The FDA has allowed Amedica to use a labeling claim that its silicon nitride discourages bacterial biofilm adhesion. That was also based on an intriguing series of studies. Those were in vitro and in vivo studies that showed that silicon nitride discourages bacterial biofilm adhesion. Which have clear application for large joint implants.
Amedica sold 50% more silicon nitride in 2014 than in 2013, which off a low base, hasn’t impressed Wall Street very much. Amedica expects to have a silicon nitride product for total joints in 2015. And the exact product applications or partnerships are still being worked out.
But Amedica’s data regarding silicon nitride interbody spacers is really interesting and may signal the beginning of clear company and product differentiation. Amedica’s spacer isn’t just a silicon nitride version of the myriad of hollow core PEEK spacers already in the market…it is an integral silicon nitride porous core, which appears to eliminate the need for bone void fillers while demonstrating equivalent fusion outcomes.
This is more than interesting. It’s different.
Enter K2M and Spinal Kinetics
So what are other spinal implant companies doing? Also innovating — albeit in different ways. Most other companies are innovating PEEK spacers by, for example, bonding titanium or other materials to the periphery to overcome its well-documented aversion to bony ongrowth. But adding new materials to PEEK also adds cost, potential failure modes, and still must be filled with expensive (DBM) or very expensive (stem cell DBM or growth factor biomaterials) biologics to facilitate fusion.
Certain key spine companies have started to get involved with Amedica. Spinal Kinetics recently signed an OEM deal with the company and plans to sell silicon nitride implants into the EU. Likewise K2M has signed on and been especially helpful with the CASCADE study investigators. Some of Amedica’s composite spacers, which are already available in Europe could come to the U.S. soon. In February Amedica filed its 510(k) for CSC with the CASCADE data.
If a Study Falls in the Forest, Will Anyone Hear It?
The CASCADE study is creative and important. That study showed that a synthetic spacer material could deliver better bony ongrowth than PEEK. Can the company make a case for a simpler, faster and less expensive approach to cervical fusions? If a study is reported will the payers notice?
Sadly, it’s an uphill battle. In the fee-for-service, stack-as-many-codes-as-you-can conundrum that is our U.S. healthcare system, the geniuses at the payers might well miss such an interesting development as the CASCADE study.
In the coming pay-for-performance world a study like this could find more takers.
Amedica’s CASCADE dilemma reminds us a little bit of another study that demonstrated equivalent fusion rates to the then-gold standard, iliac crest autograft. That study showed that a new, off-the-shelf, procedure-simplifying (albeit expensive) biomaterial delivered equivalent fusion procedures as the old, tedious standard.
Remember Infuse?
