Eli Lilly sued by Nektar Therapeutics over autoimmune disease treatment

Lilly did not immediately respond to Reuters' request for comment.

Nektar, which regained all rights to the drug earlier this year after the deal was terminated, separately said on Monday Lilly had incorrectly reported data from two early-stage studies testing rezpegaldesleukin to treat eczema and psoriasis.

Nektar said new data showed that 12 weeks of treatment with the drug at the highest dose reduced severity of eczema, also known as atopic dermatitis, by 83%, compared to 66% reported previously.

The new data also indicated that the treatment at the highest dose reduced severity of psoriasis by 44%, compared to 40% reported previously.

Nektar also said Lilly had purchased another company with a competing drug candidate that was under development.

Lilly in 2020 bought Dermira Inc, which was developing a competing atopic dermatitis drug, for about $1.1 billion in cash.

With the improved efficacy data, rezpegaldesleukin shows similar efficacy as that of Regeneron Pharmaceuticals' Dupixent, Jefferies analyst Roger Song said in a note, adding that the terminated collaboration with Lilly may turn out to be a windfall for Nektar.

Nektar said it plans to begin a mid-stage study for the drug in eczema by October.