Stelara accounted for $9.1 billion of J&J's $52 billion in global drug sales last year.
The drug is also approved to treat Crohn's disease, the skin condition psoriasis and a related form of arthritis.
However, J&J alleges that Amgen failed to follow the legal process required by that law for the companies to litigate any patent disputes.
If Amgen launches its drug, J&J said it would infringe J&J's patent on the drug's active ingredient and on its use for treating ulcerative colitis.
J&J said in a statement that Janssen is "confident in its intellectual property and has filed suit to protect its rights."
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