Legal Opinion: Fresh Attack on Enbrel Patents Is Likely

Following a court decision earlier this month, it’s very possible that Amgen will continue to enjoy exclusivity for its etanercept originator product until 2029. That would be a very lucrative outcome for the company, which pulled in $5 billion in sales for the rheumatology drug last year.

Meanwhile, 2 would-be competitors sit on the sidelines: Sandoz, which owns the etanercept biosimilar Erelzi, approved in 2016, and Samsung Bioepis, which has the drug Eticovo, approved by the FDA in 2019.

Enbrel is listed as one of the most expensive drugs in the United States, at $67,000 for a year’s supply, according to the blog SingleCare, and the drug has had the etanercept market to itself since it was launched in 1998.

To Kashyap Patel, MD, vice president of the Community Oncology Alliance and president of Carolina Blood and Cancer Care Associates in Rock Hill, South Carolina, Sandoz’s latest failed bid to crack open the market for a biosimilar etanercept is “a huge blow to the perceived success for biosimilars as a class and their promise to address drug prices in the United States.”

“Even in developed, high-income countries, the costs of delivering care—especially in chronic diseases like autoimmune disorders and cancer care—are becoming an increasing burden on national budgets, and the ability to maintain this level of spending on health care is a growing concern. Biosimilars offer the promise of addressing costs of care, improving access, and providing affordability,” Patel said.

“Even though biologics account for approximately 2% of all US prescriptions, they represent almost 40% ($120 billion) of prescription drug spending in the United States and are responsible for increasing drug spending by 70% from 2010 to 2015,” he said.

Court Rulings Are a Setback for Sandoz

In August of 2019, a District Court of New Jersey judge rejected Sandoz’s attempts to invalidate patents related to Enbrel’s manufacture and active ingredient, and on July 1, a Federal Circuit panel upheld that ruling, although with some dissent.

The main argument was whether Sandoz had demonstrated the existence of obviousness-type double patenting (OTDP). OTDP was developed as a legal means to prohibit a company from inappropriately extending patent protection by patenting the same invention twice.

In the case of Enbrel, Sandoz was unable to convince the court that this was the case. However, a dissenting judge argued against the majority that owing to subtle language in a contract between Roche and Immunex, which Amgen acquired, Sandoz did have a valid claim for OTDP.

In a public statement that expressed its frustration with the outcome, Sandoz said it was reviewing its options, including a possible appeal to the Supreme Court.

By this time, Sandoz is in deep in terms of investment in development and its legal defense of Erelzi, and the market for etanercept is large and remains tempting. Ha Kung Wong, an intellectual property law attorney with Venable of New York, said a Supreme Court appeal is likely, although he said it’s also possible that Sandoz will try for an en banc rehearing involving Federal Circuit judges. En banc rehearings are generally granted only to exceptionally weighty issues.

“The fact that there was a dissent could lead to further discussion over what the right [OTDP] analysis should be,” Wong said. This is where Sandoz appears to have the most likely grounds for appeal, he said. The drug maker also argued “written description,” meaning the claimed invention was not properly described in the patent application, and “obviousness,” essentially meaning that there was lack of true innovation in the product; however, these issues were more fact dependent in the case and are thus less likely to interest the Supreme Court, Wong said.

It’s also possible that Samsung Bioepis may invlaidate certain related patents, he noted. “There is an ongoing case on the same patents between Amgen and Samsung Bioepis. It's possible that Samsung could try to invalidate the patents. It's a little unclear what the status of this case is because it's administratively stayed based on a confidential stipulation, so we don't really know what the stay is for or what would lift it. The stay does allow for discovery to proceed, though.”

A 2017 report by the Rand Corporation predicted the potential for $54 billion in biosimilar savings over 10 years, but actual utilization doesn’t appear to be keeping up, largely because of patent walls that keep biosimilars out of the market, Patel said.

“Despite the efficacy and safety of biosimilars, the level of utilization is still less than expected in the United States due to multiple factors, including discounts and rebates to pharmacy benefits managers, patent litigation, physician and patient concerns of comparable efficacy and safety to the reference product. These prevent optimum utilization of biosimilars and the latest ruling by the US court has not helped at all,” he said.