With one drugmaker already trying to pry patent protection off of Novo Nordisk’s blockbuster Victoza before its 2022 expiration, the insulin specialist has taken new steps to deter copies. The Danish drugmaker has filed a citizen petition arguing the manufacturing process for its drug is so complex that equivalence of a copy couldn’t be certain without clinical trials.

Actually, the petition, which Novo filed last week, asks the FDA to refrain from approving ANDAs that reference any of its liraglutide-containing drugs, which include Saxenda and Xultophy in addition to Victoza, the dominant GLP-1 in the market with $2.1 billion in U.S. sales last year.

RELATED: Top 10 diabetes drugs by 2016 sales – 3. Victoza

While FDA guidance already holds biosimilar manufacturers to a higher manufacturing standard than originators, Novo argues that the "complexity of the recombinant-derived liraglutide product and its efficacy and safety is specifically tied to the manufacturing process."

It says there are no analytical tools currently available that can establish "sameness" of a synthetic generic or recombinant generic produced from a different cell line or through different manufacturing processes than Novo uses.

It points out that it is not unprecedented for the FDA to determine that a different manufacturing process might lead to a different result. Novo claims the FDA did that with nasal spray Fortical, deciding that the abbreviated path to approval wasn’t appropriate for copies of that drug.  

Teva earlier this year announced it had filed an ANDA with the FDA to produce a Victoza copy and believes it is the "first filer," which would set it up for 180 days of exclusivity if it gets a copy approved. The generic drugmaker today had little to say in response to news of Novo’s effort.

A Teva spokesperson in an email said: "We stand behind our filed ANDA for the generic version of Victoza and look forward to supporting these patients with generic medicines when otherwise able to."

RELATED: FDA's new citizen petition rules remove speed bumps for generic, biosim approvals

Whether or not the FDA eventually agrees with Novo and requires extra effort from Teva or others, the citizen petition no longer is a surefire way to delay a generic or biosimilar approval. The FDA implemented new rules this year around citizen petitions to ensure that a generic or biosim isn’t delayed by petitions that "do not raise valid scientific and/or legal issues," the FDA said.

A study last year found that 92% of citizen petitions were filed by brand-name drugmakers and that the FDA dismissed 92% of petitions filed.