Lyell(LYEL) - 2024 Q2 - Quarterly Results

Exhibit 99.1 Lyell Immunopharma Reports Business Highlights and Financial Results for the Second Quarter 2024 6 • Reported dose-dependent antitumor clinical activity in patients with relapsed/refractory triple-negative breast cancer from the Phase 1 trial of LYL797, a ROR1-targeted Chimeric Antigen Receptor (CAR) T‑cell product candidate enhanced with proprietary anti-exhaustion technology; 40% objective response rate and 60% clinical benefit rate at the highest dose cleared at the time of the initial data ...