Novo Nordisk A/S (NVO) shares plummeted 15.89% during Monday's trading session, following a significant pre-market decline. The sharp drop came after the Danish pharmaceutical giant announced disappointing results from a key clinical trial for its next-generation weight-loss drug.

The company reported that its experimental obesity drug, CagriSema, failed to achieve the primary endpoint in the REDEFINE 4 phase 3 trial. The study was designed to demonstrate that CagriSema was non-inferior to Eli Lilly's rival drug tirzepatide in reducing body weight. Patients treated with CagriSema achieved a 23% reduction in body weight over 84 weeks, compared to 25.5% for those taking tirzepatide.

This trial setback represents a significant blow to Novo Nordisk's efforts to maintain competitiveness in the lucrative obesity treatment market, where Eli Lilly's Zepbound (tirzepatide) has been gaining market share. Analysts noted that the inferior performance against the established competitor could limit CagriSema's commercial potential and make it difficult for Novo Nordisk to regain market leadership in obesity treatments.