Pfizer's launch of Lyrica will be delayed while pregabalin undergoes controlled substance scheduling at the Drug Enforcement Administration.

"Lyrica is expected to be classified as a controlled substance," Pfizer acknowledged Dec. 31.

FDA approved Lyrica Dec. 30 for the management of postherpetic neuralgia and neuropathic pain associated with diabetic peripheral neuropathy.

Pfizer expects to launch the Neurontin (gabapentin) follow-on compound before the end of 2005. Controlled substance scheduling can take anywhere from weeks to months, DEA said.

FDA forwarded the Lyrica application to DEA for scheduling following approval.

"Lyrica is expected to be classified as a controlled substance in a category with lower potential for misuse or abuse relative to controlled substances in other categories," Pfizer said.

Neurontin, which is indicated as an adjunctive therapy for partial seizures in adults with epilepsy and management of postherpetic neuralgia, is not regulated as a controlled substance. FDA indicated that it has no plans to recommend controlled substance scheduling for gabapentin.

Controlled substance scheduling could be a barrier to Lyrica commercialization. In many states, controlled substance regulations prohibit physician sampling and require patients to pick-up prescriptions at their doctor's office, preventing phone-in refills and using mail-order pharmacies.

A number of products have been successfully marketed despite controlled substance classification, including Purdue's opioid analgesic OxyContin (oxycodone) and Sanofi-Aventis' insomnia therapy Ambien (zolpidem).

However, both of these products are in markets in which all players are classified as controlled substances. Lyrica's closest competitors are not controlled agents, and may use pregabalin's controlled substance status as a marketing advantage.

Lilly's non-scheduled serotonin-norepinephrine reuptake inhibitor Cymbalta recently entered the neuropathic pain market.

FDA approved duloxetine for the diabetes-related neuropathic pain indication in September (¹ Also see "Lilly Cymbalta Diabetic Pain Launch To Piggyback On Depression Roll-Out" - Pink Sheet, 13 September, 2004., p. 11).

Lilly's Strattera (atomoxetine) has a unique status in the attention deficit hyperactivity disorder class as a non-controlled agent, which the firm uses as a key component of its promotional campaign (² Also see "Lilly Strattera Is First ADHD Agent With Adult Indication, Full-Scale Launch" - Pink Sheet, 2 December, 2002., p. 5).

In the postherpetic neuralgia market, Lyrica will face competition from gabapentin generics. Alpharma and Teva, as well as Pfizer's in-house generics division Greenstone launched generics of Neurontin in October (³ Also see "Pfizer’s “Swift Response” To Neurontin Generics Gives Greenstone 23% Share" - Pink Sheet, 25 October, 2004., p. 16).

Johnson & Johnson's Topamax (topiramate) and Cephalon's Gabitril (tiagabine) are commonly used off-label to treat neurologic maladies and are not classified as controlled agents.

Approval for Lyrica was based on six placebo controlled trials in 9,000 patients.

"Lyrica provided rapid and clinically meaningful pain reduction in a significant portion of patients, with pain relief beginning as early as the first week of treatment in some patients," Pfizer said. "Pain relief was sustained in studies of up to 12-weeks duration."

Adverse events associated with Lyrica include dizziness, somnolence, dry mouth, peripheral edema, blurred vision, weight gain and difficulty with attention/concentration. "The discontinuation rate due to side effects was low," Pfizer said.

Lyrica is "approvable" for the adjunctive treatment of partial seizures in adults with epilepsy (⁴ Also see "Pfizer’s Lyrica: “Approvable” For Three Indications, Not Generalized Anxiety" - Pink Sheet, 6 September, 2004. p. 8). Pfizer said that it is working with FDA on finalizing labeling for the epilepsy indication. Pfizer received a "non approvable" letter for pregabalin for the treatment of generalized anxiety disorder.

The unforeseen controlled substance scheduling of Lyrica foreshadows another slow launch for Pfizer. The company has recently seen disappointing launches for several new products, including the antipsychotic Geodon , the migraine therapy Relpax and the congestive heart failure agent Inspra (⁵ Also see "Pfizer Caduet Launch Set For May; Inspra Starts Slow" - Pink Sheet, 26 April, 2004., p. 6).

Pfizer Lyrica Launch Awaits Controlled Substance Scheduling

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