The US Food and Drug Administration (FDA) has approved pregabalin (Lyrica, Pfizer Inc.) for the management of neuropathic pain associated with spinal cord injury.
The drug was given priority review by the FDA for this indication, a statement from Pfizer notes, and brings to 5 the number of approved indications for pregabalin in the United States; others include diabetic neuropathy, postherpetic neuralgia, fibromyalgia, and partial-onset seizures in adults with epilepsy who take 1 or more drugs for seizures.
More than 100,000 patients, or about 40% of patients with traumatic or nontraumatic spinal cord injury in the United States, develop neuropathic pain associated with the injury. “Neuropathic pain associated with spinal cord injury can be severely debilitating and may significantly hinder rehabilitation and the ability to regain function,” the statement said.
Neuropathic pain can be experienced above, at, or below the level of injury and is typically not confined to one area of the body, the statement notes. “Approximately one-third of spinal cord injury patients report below-level neuropathic pain that is severe or excruciating,” they write. It can be begin as soon as 2 weeks after the injury and persist up to 25 years.
The approval is based on results of 2 randomized, double-blind phase 3 trials comparing flexibly dosed pregabalin (150 to 600 mg/d) with placebo in 357 patients. Patients were allowed to continue other medications, including other pain medications, such as nonsteroidal anti-inflammatory drugs, opioids, and nonopioid medications. One study included only patients with traumatic spinal cord injury, and the other included about 5% of patients with nontraumatic injuries.
Studies showed pregabalin significantly reduced neuropathic pain between baseline and 12 and 16 weeks in each study, respectively, vs placebo. More patients taking pregabalin showed 30% and 50% reductions in pain than those taking placebo. For some patients, the reduction in pain was significant as soon as week 1 and continued throughout the trial, the statement notes.
The most common adverse events with pregabalin were somnolence, dizziness, dry mouth, fatigue, and peripheral edema. Antiepileptic drugs, including pregabalin, increased the risk for suicidal thoughts or behaviors. There have been postmarketing reports of angioedema and hypersensitivity with pregabalin, the release adds. Other reactions include blurred vision, weight gain, constipation, euphoric mood, balance disorder, increased appetite, and abnormal thinking (primarily difficulty with concentration and attention).
“This milestone represents an important opportunity for physicians to more effectively manage the debilitating neuropathic pain that often accompanies spinal cord injury,” said clinical study investigator Diana Cardenas, MD, MHA, professor and chair, department of rehabilitation medicine, University of Miami Miller School of Medicine and chief of service for rehabilitation medicine and medical director of Jackson Rehabilitation Hospital, Miami, Florida, in the Pfizer statement. “Given the clinical challenges of investigating neuropathic pain in this patient population, any advancements in treatment are welcome by physicians and patients alike.”