Lundbeck Inc., a wholly owned subsidiary of H. Lundbeck A/S in Denmark announced that the US Food and Drug Administration (FDA) has granted two New Drug Application (NDA) approvals for Sabril (vigabatrin) tablets and oral solution. Lundbeck plans to launch Sabril in the United States in the third quarter.
Sabril is indicated as monotherapy for paediatric patients one month to two years of age with infantile spasms (IS) for whom the potential benefits outweigh the potential risk of vision loss, and as adjunctive (add-on) therapy for adult patients with refractory complex partial seizures (CPS) who have inadequately responded to several alternative treatments and for whom the potential benefits outweigh the risk of vision loss. Sabril is not indicated as a first line agent for CPS.
Sabril causes permanent bilateral concentric visual field constriction in 30 per cent or more of patients that ranges in severity from mild to severe, including tunnel vision to within 10 degrees of visual fixation and can result in disability. In some cases, Sabril also can damage the central retina and may decrease visual acuity. Sabril causes permanent vision loss in infants, children and adults. The onset is unpredictable and can occur within weeks of starting treatment, or sooner, or at any time during treatment, even after months or years. Because of this risk of permanent vision loss, Sabril approval is accompanied by an FDA-mandated Risk Evaluation and Mitigation Strategy (REMS) and is available only through a special restricted distribution program called SHARE (Support Help and Resources for Epilepsy).
Sabril is the first therapy approved for the treatment of IS and an important new option as add-on therapy for the approximately 30 to 36 per cent of adults with CPS whose seizures remain uncontrolled in spite of having many antiepileptic therapies already available.
"The approval of Sabril is great news for patients and their families who have been waiting a long time for access to this new therapy," said Dr. W. Donald Shields, Director of the Pediatric Epilepsy Program at the University of California at Los Angeles. "Having more than a decade of experience with Sabril, I have felt this drug was important to the epilepsy community. Lundbeck shared my commitment to getting this important therapy approved and without their support, Sabril would not be available today in the US."
Commenting on the approval of the lead compound in its central nervous system (CNS) pipeline, Jeffrey S. Aronin, president and chief executive officer of Lundbeck Inc., said, "We have been working hard to address the unmet medical needs of patients faced with infantile spasms and to offer a new add-on option for treating refractory complex partial seizures. FDA approval of Sabril is an important victory for the entire epilepsy community."
In conjunction with marketing approval of Sabril, Lundbeck has developed an FDA-mandated REMS to manage the risk of permanent vision loss associated with Sabril. The Sabril REMS, a critical component in receiving FDA approval, specifies elements, such as restricted product distribution, required vision testing and mandatory benefit-risk assessments, to manage the risk of permanent vision loss associated with Sabril. The Sabril REMS is administered through Lundbeck's SHARE programme, a comprehensive patient and physician support program designed to provide tools and resources for all of Lundbeck's epilepsy products, including Sabril. Through SHARE and the recently established SHARE Call Center, patients, caregivers and physicians will have access to information and tools to help manage severe and uncontrolled epilepsy, programs to help facilitate initial and ongoing use of Sabril, and support from a team dedicated to helping people fully understand and navigate the Sabril prescribing process.
There are three million Americans affected by epilepsy and approximately 35 per cent have CPS, the single largest seizure type, which originates from a single region of the brain and can cause impaired consciousness. Despite the availability of many antiepileptic drugs, approximately 30 to 36 per cent of adults with CPS continue to have seizures. Sabril provides a new and valuable add-on treatment option for adult CPS patients who have not responded to several alternative treatments and are considered 'refractory' to treatment. Given the potential benefit compared to the risk of permanent vision loss, it is expected that only a small percentage of refractory CPS patients will initiate and maintain treatment with Sabril as add-on therapy.
Infantile spasms is a difficult-to-treat epilepsy syndrome that usually strikes infants between three to six months old. An estimated 8,500 infants in the US have been diagnosed with IS, and each year approximately 2,500 new cases of IS are reported in the US. Sabril may not be appropriate for use in all patients with IS.
Sabril is an oral antiepileptic drug developed in the United States by Lundbeck Inc. Sabril is available in two formulations-in 500 mg tablets for use as add-on therapy for adults with refractory CPS and in 500 mg packets of powder for oral solution for infants with IS. The precise mechanism of Sabril's antiseizure effect is unknown, but is believed to be the result of its action as an irreversible inhibitor of gamma-aminobutyric acid transaminase (GABA-T), the enzyme responsible for the metabolism of the inhibitory neurotransmitter GABA. This action results in increased levels of GABA in the central nervous system. No direct correlation between plasma concentration and efficacy has been established. The duration of drug effect is presumed to be dependent on the rate of enzyme re-synthesis rather than on the rate of elimination of the drug from the systemic circulation.