INDIANAPOLIS (AP) — Eli Lilly and Co. will cease work on a treatment for lupus after research showed that its drug didn’t lead to significant improvement in patients when compared with standard treatments for the debilitating immune system disorder.

The Indianapolis drugmaker said Thursday that combined results from two, late-stage studies fell short of statistical significance, and the decision to stop studying tabalumab was not based on safety concerns. Late-stage studies are generally the last and most expensive phase of testing before the developer asks regulators to approve a drug.