Nektar’s next cytokine hope follows bempe towards the bin

After the abandonment of bempegaldesleukin last year, Nektar really needed rezpegaldesleukin to work, if only to justify the group’s ongoing work with cytokines. But the project’s failure in a phase 2 systemic lupus erythematosus trial suggests that the follow-on IL-2 asset, which had been engineered to stimulate regulatory T cells, is similarly ill-fated. None of the doses tested in the Island-SLE study met the primary endpoint, and neither was there a dose-response with the middle dose performing best, though still missing significance. True, lupus’s reputation as a tough disease to treat is justified, but Lilly, Nektar's partner on rezpegaldesleukin, has already decided to walk away from the indication; last year, it dropped the asset in ulcerative colitis. The partners are to discuss rezpegaldesleukin’s future but without Lilly’s commitment Nektar said it would not push on alone in lupus; the biotech is sitting on around $500m in cash but is already supporting other projects. Analysts from both SVB and Mizuho state that Lilly might hand back rights completely. Nektar’s shares dropped 46% at the open, leaving it with a market cap of less than $300m.

The development of rezpegaldesleukin (NKTR-358, LY3471851), past and future
Status Lilly's involvement Nektar's plans
Systemic lupus erythematosus
Ph2 trial failed Feb 2023 Abandoned Cannot afford to conduct Ph3 trials in-house; might seek partner 
Ulcerative colitis Ph2 trial terminated Aug 2022 Abandoned No plans for further development
Atopic dermatitis Ph1b trial data reported Dec 2021; Ph2 trial planned Still partnered Further steps to be discussed with Lilly
Unknown autoimmune indication Ph2 trial planned Still partnered Further steps to be discussed with Lilly
Ph1 trial data reported Sep 2022  Still partnered No explicit plans 
Source: Evaluate Pharma, clinicaltrialsgov, company communications.
Source: company presentation.

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