The Food and Drug Administration (FDA) has approved etanercept-szzs (brand name: Erelzi), a biosimilar form of etanercept (Enbrel), to treat rheumatoid arthritis (RA), psoriatic arthritis, ankylosing spondylitis, polyarticular juvenile idiopathic arthritis as well as plaque psoriasis. Earlier this year, infliximab-dyyb (Inflectra), a biosimilar version of infliximab (Remicade), became the first FDA-approved biosimilar for inflammatory types of arthritis in the U.S.
Although biosimilars for arthritis and other conditions have been approved in other countries, only one other biosimilar – a drug used during cancer treatment – has been granted FDA approval in the U.S.
Similar but not Identical
Biosimilars are expected, once they get to market, to be lower-cost versions of the existing FDA-approved biologic therapies – a bit like generic drugs, but with one notable difference: Generics are exact copies of chemically synthesized medicines, such as antacids or blood pressure drugs. Biosimilars are “highly similar” copies of biologics – drugs made from living cells that are impossible to replicate exactly.
To receive FDA approval, a biosimilar must demonstrate in rigorous comparative testing to show that, among other things, it is as safe and effective as the original drug (called reference product). It also must work the same way, come in the same form and have the same dosage options. Consequently, the side effect risks are also the same. Etanercept-szzs comes with a boxed, or prominent, warning on the prescription insert about an increased risk of serious infections and cancer – the same warnings carried by etanercept.
In early August, Johns Hopkins researchers published an analysis of 19 studies comparing branded anti-TNF biologic drugs – including etanercept – and their biosimilars in patients with RA, psoriasis or inflammatory bowel disease. The analysis, published online in Annals of Internal Medicine, showed that biosimilars were just as effective and safe as the originals. It also found that patients who switch to a biosimilar did just as well as they had on the reference drug.
In accordance with FDA guidance, the name of a biosimilar needs to be unique for ordering, prescribing and record-keeping purposes. Erelzi is known as etanercept-szzs – the core name plus a unique four letter suffix – to differentiate it from the reference product etanercept (Enbrel).
Biosimilars were developed in part to help lower drug costs. Branded biologics, which can run thousands of dollars a month – often with high co-pays – are among the most expensive drugs in the country. Biosimilars are expected to cost about 20 to 30 percent less, but prices may decrease further as more of them enter the market. According to information technology company IMS Health, at the end of 2015, there were at least 40 different biosimilars for arthritis in development. A biosimilar version of the drug adalimumab (Humira) has been submitted to the FDA for approval.
Rheumatologist Eric Matteson, M.D., professor of medicine at Mayo Clinic in Rochester, Minn., says that once the drug does come to market, its lower cost may mean that more patients will be able to use it.
“It will add to the medications available for treating rheumatoid arthritis and other approved indications, and hopefully will contribute to improved access to these medications for patients suffering from these diseases,” he says.
That doesn’t mean patients will be seeing etanercept-szzs or infliximab-dyyb any time soon, however. Even with FDA approval, each faces uphill battles. Patent disputes may keep them tied up in court for years. Patents protecting some of the ingredients in etanercept won’t expire in the U.S. for more than a decade. Earlier this year, Amgen, which manufactures Enbrel, filed a patent infringement suit against Sandoz, the maker of etanercept-szzs. The case is expected to go to trial in April 2017.
Author: Linda Rath for the Arthritis Foundation