European stocks were steady on Tuesday, with heavyweight Novartis AG weighing on the market after suffering its third clinical-trial setback in a week. The Stoxx 600 fell 0.1% at the close in London, with the healthcare sector down 2.3%. Novartis shares fell as much as 11% in its worst day on record after it said del-desiran, a treatment for a rare muscle-wasting disease, failed a late-stage study.

The repeated setbacks have raised concerns about the company's drug pipeline and near-term growth prospects. Investors remained cautious as other major pharmaceutical companies also reported mixed results, contributing to a muted session across the region.