FDA has deemed UCB's anti-seizure medicine Vimpat "not approvable" for diabetic neuropathy pain, an outcome the firm says could reflect the "mixed data" supporting the application and the challenges of conducting pain studies generally.

UCB submitted the NDA for Vimpat (lacosamide) for approval in diabetic neuropathy pain and partial onset seizures last September (¹ Also see "UCB’s Vimpat NDA Seeks Indications For Epileptic Seizures, Diabetic Pain" - Pink Sheet, 29 November, 2007.). FDA's review of the seizure indication, which is being conducted by a separate FDA division, is ongoing, and the company says it is confident of its prospects.

FDA's communication was very brief and did not elaborate on the reasons behind the rejection, the firm said in an interview July 29, the day it disclosed the rejection.

The Belgian biopharma speculates that its submission could have been turned down due to "mixed data" and the use of an unconventional study technique. Nevertheless, UCB says it remains fully committed to the indication and reaffirms Vimpat's potential value in treating diabetic neuropathy pain.

In one trial, Vimpat achieved statistical significance in relieving pain. In another, it missed its primary endpoint but achieved secondary endpoints by improving quality of life and positively affecting other pain indicators.

The third study showed Vimpat was effective, but a non-conventional "withdrawal" study design was used, whereby participants started on lacosomide and then half were switched to placebo.

Defending the study design and the mixed data, UCB pointed out that the experience of pain is very subjective and that there is a need for new ways to measure improvements. Diabetic neuropathic pain is particularly difficult to treat, the firm added.

Vimpat seemed to have been following in the footsteps of Pfizer's Lyrica (pregabalin), which was reviewed by several FDA divisions before winning approval in 2004 for diabetic peripheral neuropathy and partial onset seizures associated with epilepsy.

UCB acquired Vimpat through the 2006 purchase of Schwarz Pharma of Germany, which conducted the three studies supporting the NDA for the diabetic pain indication (² Also see "May The Schwarz Be With You: UCB Proposes $5.6 Bil. Acquisition" - Pink Sheet, 25 September, 2006.). Dual-action Vimpat is designed for selective enhancement of slow inactivation of sodium channels and modulation of collapsin-response mediator protein-2.

Patients are commonly given tricyclic antidepressants or antiepileptic medications for diabetic pain, but side effects can be problematic. Eli Lilly's Cymbalta (duloxetine) is another option for the condition.

Writing in a May 19 research note, London-based JP Morgan analyst Annie Cheng had expressed doubts that Vimpat would prove viable.

"We believe the efficacy of this drug is marginal, and compared to standard of care, not as well tolerated," Cheng wrote in May. "There is a real chance that the FDA will not approve the drug on the action date. Even if Vimpat is approved, we believe it would have limited uptake."

-Emily Hayes (e.hayes@elsevier.com)

UCB’s Vimpat Falters In Diabetic Pain

More from Archive

More from Pink Sheet