Heron Therapeutics (HRTX) said Tuesday that the US District Court for the District of Delaware has ruled that claims in two of its Cinvanti injectable emulsion patents are invalid.

The ruling stems from litigation with Azurity Pharmaceuticals and does not affect prior settlements involving Cinvanti or Aponvie, the company said.

Heron said it plans to appeal the decision to the US Court of Appeals for the Federal Circuit and continue defending its intellectual property rights.

Shares of Heron Therapeutics were down more than 15% in premarket activity Tuesday.