Intrathecal Baclofen 'Underutilized' for MS Spasticity: Report

Megan Brooks

February 11, 2011

February 11, 2011 — In patients with severe spasticity related to multiple sclerosis (MS), intrathecal baclofen (ITB) using a programmable, subcutaneously implanted pump can be an effective alternative to oral antispasticity medications, concludes an expert panel that reviewed the literature on ITB and developed recommendations for its use in the MS population.

"ITB therapy has demonstrated benefit and should be evaluated as an option for patients with spasticity at all stages of MS who are intolerant of or unresponsive to oral therapies," the panel concludes.

"There are a lot of misconceptions about the intrathecal baclofen pump and the efficacy and safety related to it," panel member Mary Hughes, MD, of Neuroscience Associates in Greenville, South Carolina, noted in an interview with Medscape Medical News.

Dr. Mary Hughes

"This was an attempt to bring people together who are very experienced in use of the pump, review the literature, and disseminate this information," said Dr. Hughes, who is also chair of the Division of Neurology in the Greenville Hospital System.

Together, the panelists have more than 100 years of clinical experience ( > 1500 patients) in the use of ITB for MS-related spasticity.

"Rewarding" First-Hand Experience

"I see patients every day who can't tolerate the side effects of large doses of (oral) medication necessary to treat the most severe cases," Dr. Hughes said in a statement.

She said she's seen firsthand how ITB can reduce severe spasticity and improve quality of life. "As a clinician managing a disease that is chronic and progressive, to be able to say that for this specific symptom [spasticity], here is a treatment that will increase your ability to remain independent and offer that in a safe way that's going to be effective long-term, that is very rewarding," she told Medscape Medical News.

The panel's findings and recommendations were published online January 31 in the Multiple Sclerosis Journal. Their work was sponsored by Medtronic, Inc., which markets ITB using the SynchroMed II pump.

Asked for his opinion on IBT, Nicholas G. LaRocca, PhD, vice president of healthcare delivery and policy research for the National Multiple Sclerosis Society, who did not participate in the research, said, "If a treatment isn't working or the side effects are unacceptable, it certainly is important for physicians to consider an alternative and the baclofen pump certainly is an alternative."

Dr. Nicholas G. LaRocca

ITB Effective but Underutilized

"Current data," the panel writes, "indicate that ITB therapy effectively and significantly reduces severe spasticity in ambulatory and nonambulatory patients with MS." In a study of 131 patients with severe MS-related spasticity, for example, the mean Ashworth score dropped from 4.2 before implantation to 1.3 after ITB was started (P < .0005). Improvements in spasticity led to improvements in pain, sleep, and increased physical activity; 18 patients also saw improvements in gait and balance. Other studies have reported similar improvements with ITB, the panel notes.

However, nearly 2 decades after ITB therapy was first approved by the US Food and Drug Administration for severe spasticity, it remains underutilized, Dr. Hughes and colleagues report. For example, in a 2004 survey of 18,727 patients with MS, 84% reported at least some symptoms of spasticity and 30% reported moderate to severe spasticity. Of the 13% of patients who were candidates for ITB, only 1% received it.

The panel says there are a variety of reasons why ITB is underutilized. "Clinicians may be more focused on disease-modifying therapies rather than symptom control," they point out.

They may also underestimate the effect of spasticity on quality of life, be unaware of the potential benefits of ITB, or be unsure how to select appropriate patients. According to the panel, fewer than half of all MS centers have comprehensive spasticity management programs. Cost and safety concerns also probably exist.

Current guidelines for managing MS-related spasticity recommend oral baclofen or tizanidine with careful dose titration to obtain the desired effect. Patients, however, may either fail to respond adequately to oral antispasticity medications or have trouble tolerating the side effects, which include drowsiness and dizziness. "Unlike an oral therapy, with intrathecal therapy you don't get many of the systemic side effects," Dr. Hughes noted.

The most prominent side effect with ITB, the panel notes, is hypotonia, which occurs in about a third of patients and can be addressed by adjusting the rate of administration. Other common side effects include headache and nausea/vomiting.

As part of their research, the panel reviewed data collected between August 3, 2003, and October 24, 2008, via the Medtronic Implantable Systems Performance Registry. They report that roughly 70% of the more than 4000 pumps implanted were the SynchroMed II model, with most of the remainder being the earlier and now-discontinued SyncroMed EL model.

The registry contained a total of 1982 "event" reports; 38 (2%) were pump-related and 32 of these were reported with the discontinued model. Twelve percent of event reports were related to the procedure or therapy delivery, and all events were readily manageable.

Trial and Training

Before implantation of an ITB pump, a screening trial to determine whether ITB will be effective and to assess any adverse reactions is recommended, the panel notes. The trial, which can be done on an outpatient setting, involves intrathecal administration of a bolus test dose of baclofen by lumbar puncture. "A decrease in 1 to 2 points in the modified Ashworth score and/or a decrease of at least 2 points in the spasm frequency score constitutes a positive response to the screening trial," they note.

It's also important to screen patients for their willingness and ability to attend follow-up appointments to refill the pump and make adjustments. Patients who skip regular follow-up appointments are at risk for baclofen withdrawal and other complications of being unmonitored by the care team. "Abrupt cessation of ITB can result in high fever, drowsiness and/or coma, return of spasticity, muscle rigidity, and in rare cases death," the panel notes.

"There does need to be a certain amount of expertise with managing the intrathecal baclofen pump as well as choosing the right patient, but with appropriate training and experience, physicians can learn how to do this," Dr. Hughes told Medscape Medical News.

"It's not difficult to refill and maintain the pump; nurses are often trained to do this," she said. In her opinion, "it's the awareness of [ITB] and going through the process and making it available to our patients. It can be challenging to get physicians to adopt new technology, many practice medicine like they did when they were in training."

The research was supported by Medtronic, Inc., of Minneapolis, Minnesota. Several of the panel members have financial relationships with Medtronic and other companies. Dr. LaRocca has disclosed no relevant financial relationships.

Mult Scler. Published online January 31, 2011.


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