Shire, armed with new rare disease patent, aims to block CSL's Haegarda launch

Anticipating an FDA approval later this year for a promising hereditary angioedema med from CSL, Shire has taken a preemptive strike at the Australian drugmaker. In a new lawsuit, it’s asking a court to block the launch.

Filed last week in U.S. District Court in Delaware, Shire’s lawsuit contends that CSL is gearing up to launch a drug, Haegarda, that will step on its own brand-new patent, issued just last week. Shire demands a permanent injunction that bars CSL "from making, importing, using, selling, or offering to sell in the United States" an HAE med that infringes it.

Shire's attempt to block the launch follows Amgen's successful bid for an injunction against Sanofi and Regeneron, which make Praluent, a PCSK9 cholesterol drug that rivals its own Repatha. That injunction, if upheld on appeal, would push Praluent off the market, unless the two sides agree on royalties. It would be the first such move against a rival drug in almost a decade.

Shire's lawsuit differs in that the patent it's asserting is newly minted. The company last week received a specific method patent for subcutaneous HAE treatment with a composition comprising a C1 esterase inhibitor, among other stipulations. It filed its lawsuit against CSL the same day.

Shire says CSL’s candidate, expected to be green-lighted by the FDA by August, violates that patent.

In a statement, a CSL spokesperson said the company "remains highly confident" its drug "does not infringe any valid claim of the Shire ViroPharma patent and will vigorously defend against the claims."

RELATED: Sanofi, Regeneron ask court to shield Dupixent from Amgen patent attack

Shire markets HAE meds Cinryze, Firazyr and Kalbitor already, and it's working on a subcutaneous prophylactic C1 esterase inhibitor dubbed SHP616, among other candidates.

In its lawsuit, Shire points to the extensive efforts CSL has undertaken to get ready for its Haegarda launch, expected later this year.

The Irish drugmaker says CSL has completed phase 3 trials, filed for U.S. marketing approval, announced the upcoming launch, hired personnel and started manufacturing batches in anticipation of approval. Those actions all “will imminently infringe and/or actively induce others to infringe” Shire’s patent, the suit claims.

RELATED: Sanofi, Regeneron avoid Praluent disaster as appeals court stays injunction in PCSK9 patent case

Shire’s action is the latest in a series of suits by drug companies looking to hit at competitors' launches through courtroom disputes. In addition to Amgen's move against Sanofi and Regeneron, the latter two companies sued Amgen ahead of its Dupixent approval seeking a declaration that its new atopic dermatitis med doesn't infringe Amgen's intellectual property.

After Amgen experienced initial success in getting a court to place an injunction on Sanofi and Regeneron’s PCSK9 med, a judge placed a stay on that decision, which would have required the partners to withdraw Praluent from sale in the U.S.

Meanwhile, Merck & Co. and Gilead have been locked in a fight over patents covering hepatitis C drugs. Most recently, Merck won a record $2.54 billion judgment in that case, which Gilead said it would appeal.