An advisory committee to the Food and Drug Administration last week recommended the approval of generic versions of two expensive arthritis drugs, which if approved by the agency could be good news for health care spending and patients burdened by high drug prices.
But the action served as a reminder that the agency still must issue key guidelines on how to evaluate whether generic drugs in this class are fully interchangeable with their original products.
And these two new generics could be delayed because of questions over the patents for the original products.
The original drugs, Humira and Enbrel, are biologics, treatments derived from cells and living cultures, instead of small chemical molecules common in most drugs. Biologics are difficult to develop and as a result are very expensive. Doses of each drug can cost thousands of dollars a month, and Humira, which has more than $12 billion in annual sales around the globe, is the best-selling drug in the world.
The drugs are important because they treat a variety of conditions including rheumatoid arthritis, an immune disorder that causes joint damage, and plaque psoriasis, a skin condition.
For Medicare, which spent $1.2 billion on 50,000 patients using Humira in 2014, a generic version could mean some relief. Jeremy Schafer, a vice president at healthcare economics consultancy Precision for Value, said that these kinds of drugs will continue to be a big part of health care spending.
“They are very meaningful because this is a category that’s been growing year over year not only in price but in utilization as well. More patients have been using them and the price of many of the products has been going up,” he said.
Because of their complexity, the generic versions of biologics are known as biosimilars, a name meant to emphasize that even slight changes in their production could result in a product that’s similar, but not exactly the same.
The advisory committees last week recommended that the FDA approve both biosimilars for use on the same conditions that the original drugs are used to treat. It might seem obvious to state that a generic drug can be used for the same conditions as the original, but for biosimilars, the FDA has still not put out guidelines for determining whether the drugs are indeed fully interchangeable with the original product.
There are so far only two biosimilars approved by the FDA, and the arthritis drugs considered this week would represent the third and fourth. Even though the market is still very small, the lack of guidance on interchangeability could have a real impact.
Seth Ginsburg, co-founder of an arthritis support organization called CreakyJoints, said that patients will likely be reluctant to switch to a generic treatment if they are already using the original product.
“Patients are indeed concerned about switching because there has not been substantial or sufficient studies or evidence about what happens when you switch,” he said in a phone interview.
The uncertainty around biosimilars has also concerned lawmakers. After establishing the FDA’s authority to approve biosimilars in 2010 in the health law, lawmakers are frustrated that so few have hit the market.
“Numerous products are waiting to proceed through the approval process and many physicians, patients and concerned individuals like myself are concerned with the lack of progress,” Texas Republican Rep. Joe L. Barton, who was heavily involved with giving the FDA the authority, said at a hearing in February.
In recent years, Congress tried to prod the FDA into action through report language accompanying the measure that funds the FDA. This year, committee reports from both chambers request that the agency work to educate patients and doctors about biosimilars. Senate appropriators also requested that FDA provide timelines for publishing the outstanding draft guidances.
FDA officials have said they want to publish the draft guidance on interchangeability this year. Regarding the guidance on naming, Sandy Walsh, an FDA spokesperson, said “the FDA continues to review comments and work on a final version of the guidance.”
David Rosen, a former FDA official who is now at the law firm Foley and Lardner, said in an interview that it’s important for the FDA to use the applications it's currently considering as a model to ultimately get the guidance right. He said that the quality of the data that the companies have provided should still give doctors and patients confidence that the products work, even if they aren’t yet considered interchangeable.
“The companies are finding that they can still have a market for biosimilars without having an interchangeability rating,” he said.
Even if the drugs are approved by the FDA in coming months, it still might be years before the generic versions come to market, because of the threat of lawsuits from makers of the original drugs. The patent life of biologic drugs is 12 years, but there are outstanding legal questions about whether the patents can be extended based on the approval of the drug for new uses.
For instance, Humira’s patent is set to expire this year, but it was approved to treat Crohn’s disease in 2007, making some observers wonder whether Amgen, maker of the proposed generic version, will wait several years to put its drug on sale and avoid the threat of a lawsuit. Executives from AbbVie, the company behind Humira, have said they think that biosimilar versions shouldn’t come to market before 2022.