Some pharmacy companies think biosimilars could fit into the existing system for tracking prescription drugs and tracing adverse events, but FDA could be leaning toward an alternative system.

During the first day of a two-day hearing on application of the biosimilar and interchangeable products pathway, representatives of CVS Caremark Corp. and Express Scripts Inc. tried to convince FDA officials the existing system of manufacturers and lot numbers is the best way to track adverse events with biosimilars and that they should not be given a new unique name.

The companies argued tracking can be improved by requiring more specific information in the adverse event reports.

But John Jenkins, director of the CDER Office of New Drugs, seemed to disagree and continually asked questions probing how FDA could track spontaneous adverse events with biosimilars given the same name as the reference product.

Jenkins said the make-up of biologics will not translate as easily into the current pharmacovigilance system as generic drugs because the agency cannot be as confident active ingredients are always the same and manufacturing processes will not cause changes to the safety profile.

"We can't assume even the innovator or the biosimilar stay the same all the time," he said. "There's always a possibility something will get approved that does in fact have a clinical consequence that we didn't detect or weren't aware of. I'm still wondering about for spontaneously reported adverse events where I think it's extremely rare for the NDC code to be on the report, how do you think we would be tracking back to the appropriate product?"

Lot Number Tracking Has Been The Best Protection

The agency is seeking comments on whether biosimilars should be given a new unique name, such as a distinguishing prefix or suffix, to identify products that are interchangeable, biosimilar and not biosimilar. FDA already has said it "must" be able to tell the difference between products for pharmacovigilance purposes (Also see "Biosimilars: FDA's Meeting Notice Upgrades Safety To "Paramount"" - Pink Sheet, 4 October, 2010.).

The generic industry believes the existing safety system is well-tested and the manufacturer and lot number system has been proven to be effective in tracking and tracing adverse events. Brand companies disagreed, saying traceability should not be sacrificed in the name of cost savings (Also see "Biosimilars On The Horizon: How Much Will FDA Look To The East?" - Pink Sheet, 1 November, 2010.).

The pharmacy companies also did not appear supportive of further complicating the system already in place or adding another layer of pharmacovigilance specifically for biosimilars.

Steven Russek, who represented Medco Health Solutions, said adding a prefix or suffix makes sense for products that are not considered interchangeable, otherwise the names should be the same.

Scott Reid, CVS Caremark senior vice president of specialty pharmacy operations, said pharmacy management systems have been built to accept additional information about certain drugs' reimbursement codes, including whether some biosimilars have been approved as interchangeable with the reference product.

Reid said some biosimilars could require a unique name in specific cases, such as encouraging utilization in Medicare Part B, but overall a single identifier was sufficient.

Steve Miller, Express Scripts senior vice president and chief medical officer, research and clinical sciences, said the existing safety system will prevent confusion and FDA still will be able to identify problematic lots of a drug if adverse events are reported.

Miller also said there may be a time where a biosimilar may need a unique name, but it still may not solve some problems. He said the current system works because of its simplicity and introducing separate biosimilar naming could open the door to more problems.

"Having that data down to the individual lot number and NDC is actually been what's held us in the best sted," Miller said. "The solution actually ... even amongst lots now is adhering to actually entering the NDC. It's not asking to add now two different unique things. So you really want the system to be as simplistic as possible."

Biosimilar Naming and Missing Adverse Events

FDA appeared to be concerned about confusing or missing adverse events occurring in patients taking biosimilars because of the naming issue. The agency also has concerns about ensuring prescribing and dispensing are safe when biosimilars come to the market, including preventing unsafe product substitution.

It already has been suggested the agency could boost the post-marketing requirements for biosimilars. Jenkins said it is rare to get detailed information from spontaneous adverse event reports, although he acknowledged that many injectable biosimilars come in vials that contain lot numbers that would help with tracking.

Jenkins also asked how under the current system FDA could distinguish rare adverse events among biosimilars if the problems did not occur frequently enough during FDA's review.

"With the biosimilars ... there's always going to be some level of residual, I think, uncertainly that the active ingredient is in fact the same...," he said. "There are ... structural differences that could trigger a different profile of rare adverse events. You're right the current system isn't perfect, but I'm just concerned that we're adding another factor with the biosimilars, that being the inability to be as confident about the active ingredient being the same as we can for small molecules."

-Derrick Gingery (d.gingery@elsevier.com)

FDA Signals Interest In Requiring Unique Biosimilar Names

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