Back pain is traditionally treated first with non-surgical management — physical therapy, pain medications and injections — before the patient potentially becomes a surgical candidate. However, many of these non-operative treatments are for pain relief and may not actually heal a chronic issue.
The next option would be lumbar spinal fusion or total disc replacement. "There hasn't been the ability to repair a disc in the past," says Domagoj Coric, MD, of Carolina Neurosurgery & Spine Associates in Charlotte, N.C., and Chief of Neurosurgery at Carolinas HealthCare System’s Carolinas Medical Center. "However, if you look at biologics and disc repair, there are cell-based therapies that show promise for the future."
From a basic science perspective, the disc's nucleus includes native cells — disc cells — that produce an extracellular matrix to keep the disc healthy. When the disc cells don't produce enough, the disc dehydrates and that can cause pain.
"At the end of the day, these biologics are focused on replenishing the cells and extracellular matrix," says Dr. Coric. "There are three basic types of cells that can be utilized for disc repair: (1) stem cells (2) cartilage cells and (3) disc cells. And there are three separate investigational efforts to evaluate these distinct cell types for the treatment of low back pain."
Stem cells — Mesoblast's stem cell therapy involves extracting allogeneic mesenchymal stem cells and expanding them in cell culture. These stem cells are then combined with a hyaluronic acid carrier and injected into the disc space. Dr. Coric's investigational site at Carolina Neurosurgery and Spine Associates was one of the leading enrollers in Mesoblast's 100-patient Phase 2 clinical trial which has recently released positive 12-month outcome results.
"Patients were randomized to receive a placebo injection of saline alone or carrier alone with others receiving 6 million stem cells or 18 million stem cells," says Dr. Coric. "The patients who received the cells reported more sustained improvement. We're hoping to conduct a larger pivotal trial in the future."
Chondrocyte cells — ISTO Technologies' NuQu procedure utilizes donor juvenile chondrocyte cells which are expanded out in cell culture to hundreds of millions of cells which are separated into 5 million to 10 million cell batches and combined with a fibrin carrier. NuQu has published positive results from their Phase 1 pilot study and completed enrollment in a 46 patient Phase 2 study.
Disc cells — A third company — DiscGenics — is looking to begin a Phase 1 trial this year with actual disc cells. For this treatment, disc cells are extracted from a donor tissue source and then the DiscGenics technology isolates the disc cells to produce bioactive Discopheres that are combined with a scaffold and injected into the degenerated disc. The therapy is designed for the cells to excrete new proteins and sugars to regenerate the disc.
"The advantage to disc repair injections are that they are outpatient procedures," says Dr. Coric. "They aren't major procedures like fusions. You don't have to put instrumentation in the spine. Here the concept is to get the disc to repair itself. The injections are percutaneous and can take anywhere from 10 to 15 minutes. It's what patients are looking for in terms of minimally invasive surgery while not burning any bridges for other procedures. In a lot of ways, it's a cutting-edge therapy to repair the disc instead of removing the disc."
If proven effective, these types of biologic injections would fill the gap currently between non-operative treatment and surgery for patients who don't respond to non-operative treatment.
"There are some people who have back pain that are recalcitrant to the current non-surgical measures, and those people only have the options of chronic pain management or having a substantial spinal operation," says Dr. Coric. "There is a whole area here where there isn't an effective treatment modality."
These biologic injections could have a huge impact on the economics of back pain if they are able to improve patients who would otherwise become chronic users of long-acting narcotics or multiple epidural steroid injections, which can become expensive if they are used regularly over several years.
"The Mesoblast and NuQu studies have shown positive results after a single injection for one to two years," says Dr. Coric. "That changes the financial impact of back pain. You don't have to get multiple injections or be subjected to chronic narcotic therapy. While the jury is still out on the clinical trials, I think this could change the paradigm because there isn't anything between non-surgical management and major operations."
The FDA hasn't granted approval for any biologics yet, as they are still in investigational trials; however, Dr. Coric speculates there will be further trials later this year or next year and if all goes well, FDA approval could follow. "There is really good basic science behind cell therapy and I think the real potential exists that we are going to continue to see positive results in the trials," he says.
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