Jill Wechsler

A House Energy and Commerce subcommittee held hearings in April 2011 and again in March 2012 to examine how DEA is tracking and preventing inappropriate prescription-drug use, the effectiveness of state prescription drug monitoring programs, and how well manufacturers, distributors and pharmacists prevent illegal diversion. Subcommittee Chair Rep. Mary Bono Mack (R–CA), has pressed for policies to aggressively curb access to painkillers and anxiety drugs more severely since the suicide of her son related to oxycontin abuse.

Of the thousands of pharmaceuticals approved by FDA for US marketing, about 250 are regulated by the the Controlled Substances Act of 1970 (CSA). Some 80 drugs with high abuse potential but important medical uses fall under schedule II, including sleep aides, diet pills, antidepressants, psychiatric drugs and antihyperactive therapies, as well as painkillers. Another 150 drugs have relatively low abuse potential and are in schedules III–V with minimal restrictions, while more than 130 schedule I drugs are dangerous and not approved for any uses.

Recent legislation also authorizes more aggressive efforts to remove leftover prescription drugs from family medicine cabinets, and DEA is holding another national "take-back" initiative this month, aiming to collect tons of expired or unwanted medicines for proper incineration. Brand and generic-drug manufacturers support these efforts, but are wary of proposals from the state of Washington and a California county that call for manufacturers to foot the bill for more extensive collection of leftover prescriptions.

Seeking DEA approval

Another concern for industry is that added requirements for bringing Schedule II therapies to market can delay patient access to new drugs by six months or more. DEA also sets annual quotas on production of controlled drug substances, a factor that may aggravate shortages of certain widely used drugs.

FDA assesses about one-third of new drug applications (NDAs) to see whether they warrant additional scheduling review by the DEA, noted Douglas Throckmorton, deputy director of the Center for Drug Evaluation and Research (CDER), at a February 2012 seminar on controlled substance regulation sponsored by the Food and Drug Law Institute (FDLI). CDER's Controlled Substance Staff (CSS) determines whether DEA should evaluate the product further, which can lead to a complex scheduling process after FDA approves the NDA.

This DEA review, for example, delayed marketing 11 months after FDA approval in 2008 of Esai's sedation medication Lusedra (fospropofol). GlaxoSmithKline had to wait nearly six months to market its new epilepsy drug Potiga (ezogabine), despite early communication with DEA on the product's unique features. DEA scheduling "is a big black box for industry," observed Esai regulatory policy executive Ginny Beakes-Read, with no timelines for its actions and recommendations.

FDA officials advise manufacturers to address scheduling issues early in drug development to facilitate the review process. Sponsors need to characterize whether a drug produces positive psychoactive effects, such as sedation, euphoria and cognitive distortion, explained CSS pharmacology team leader Silvia Calderon-Gutkind. NDA's should clearly identify abuse liability—or its absence—through evaluation of chemical properties, pharmacological and pharmacokinetic characteristics and clinical data relevant to abuse.

CDER is working to improve its internal assessment process for controlled substances and to negotiate a memorandum of understanding with DEA to facilitate exchange of confidential information on new drugs earlier in the review process. FDA issued draft guidance last year on how manufacturers should assess the abuse potential of new drugs, and advice on developing abuse-deterrent formulations is expected this year.

Although there's great interest in abuse-resistant patches or capsules, so far none have emerged that are "truly effective," said Gary Boggs, executive assistant in DEA's Office of Diversion Control, at the FDLI meeting. Manufacturers look to add antagonists or change formulations to improve resistance, but DEA wants data to show that it works and warrants "down-scheduling" to a DEA category that carries less regulation of production quantities, physical security, prescribing, and distribution.

Ultimately, better science may establish a clearer roadmap for assessing drug pharmacology and clinical studies related to abuse issues, particularly for new drugs with novel mechanisms of action. Criteria for identifying and reporting adverse events related to prescription-drug abuse also could provide safety data that supports changes in controls, as would efforts to increase prescriber and patient education on the appropriate use of opioids and abused drugs.