Eli Lilly Terminates Three Drug Programs Over Efficacy Concerns

Eli Lilly has confirmed it is discontinuing the development of three investigational therapies after they failed to meet efficacy expectations. The terminated assets include LY3884963, a gene therapy acquired through Lilly’s $1bn acquisition of Prevail Therapeutics in 2022. The therapy was being evaluated in a Phase I/II trial in frontotemporal dementia with progranulin mutations (FTD-GRN). Lilly said the decision was based on a lack of compelling efficacy, not safety concerns.

Lilly is also ending development of LY3541860, an anti-CD19 antibody studied in multiple sclerosis and rheumatoid arthritis, as well as AC-225-PSMA-62, a radioligand therapy for prostate cancer. Both programs were halted due to insufficient efficacy.

All three assets were excluded from Lilly’s Q4 2025 pipeline update. Despite the cuts, Lilly continues to invest heavily in gene therapy, with recent deals involving Seamless Therapeutics, Rznomics, and Verve Therapeutics, while projecting 2026 revenues of up to $83bn.

08-02-2026