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Exhibit 99.1 Lyell® Lyell Immunopharma Reports Business Highlights and Financial Results for the Second Quarter 2026 • • . • PINACLE pivotal clinical trial evaluating ronde - cel in 3L + patients with LBCL on track to report additional data in second half of 2026 , with pivotal data expected mid - 2027 and BLA submission expected to follow in the second half of 2027 Presented updated ronde - cel data in more than 100 patients with relapsed / refractory LBCL at the EHA 2026 Congress , with Phase 1/2 safety data showing no Grade ≥ 3 CRS and low rates of Grade ≥ 3 ICANS supporting potential outpatient administration Reported updated LYL273 safety data in relapsed / refractory mCRC , with gastrointestinal prophylaxis regimen and standardized safety management plan reducing Grade ≥ 2 diarrhea or colitis from 55 % to 10 % ; amended ongoing U.S. Phase 1 trial to a Phase 1/2 design to enable seamless expansion into a potential pivotal single - arm Phase 2 trial pending regulatory alignment Additional data from the U.S. Phase 1 trial of LYL273 in 3L + patients with relapsed / refractory mCRC and End - of - Phase 1 FDA meeting are expected in the second half of 2026 Approximately $ 228.0 million in cash , cash equivalents and marketable securities as of June 30 , 2026 , expected to provide runway into Q3 2027 SOUTH SAN FRANCISCO , Calif . , August 6 , 2026 -- Lyell Immunopharma , Inc. ( Nasdaq : LYEL ) , a late - stage clinical company advancing a pipeline of next - generation chimeric antigen receptor ( CAR ) T - cell therapies for patients with cancer , today reported financial results and business highlights for the second quarter ended June 30 , 2026 . Second Quarter Updates and Recent Business Highlights Rondecabtagene Autoleucel ( Ronde - cel ) : A next - generation dual - targeting CD19 / CD20 CAR T - cell product candidate designed to increase complete response rates and prolong the duration of response as compared to approved CD19 - targeted CAR T - cell therapies for the treatment of large B - cell lymphoma ( LBCL ) Ronde - cel is an autologous CAR T - cell product candidate under evaluation in two pivotal trials in patients with relapsed / refractory ( R / R ) LBCL in the third- or later - line ( 3L + ) setting ( PiNACLE ) and the second - line ( 2L ) setting ( PiNACLE - H2H ) . Ronde - cel targets B cells that express either CD19 or CD20 with a true ' OR ' logic gate to achieve full potency at either target and is manufactured with a process that enriches for CD62L - positive cells to generate more naïve and central memory CAR T cells with enhanced stemlike features and antitumor activity . The U.S. Food and Drug Administration ( FDA ) has granted ronde - cel Regenerative Medicine Advanced Therapy ( RMAT ) and Fast Track designations for the treatment of adults with R / R diffuse large B - cell lymphoma ( DLBCL ) in the 3L + setting and also RMAT designation for the treatment of large B - cell lymphoma ( LBCL ) in the 2L setting . The FDA has also granted ronde - cel Orphan Drug Designation for the treatment of DLBCL / HGBCL with MYC and BCL2 rearrangements . • In June 2026 , Lyell presented updated safety data and translational insights for ronde - cel in two presentations at the European Hematology Association ( EHA ) 2026 Congress in Stockholm , Sweden . ° ° Safety data from more than 100 patients with R / R LBCL treated with ronde - cel ( 65 in the 3L + setting and 43 in the 2L setting ) were presented . There were no Grade ≥ 3 CRS events and low rates of Grade ≥ 3 ICANS reported in the Phase 1/2 trial as of the data cutoff date of May 5 , 2026 , supporting the potential for outpatient administration . The manufacturing success rate was 97 % . Translational analyses were presented providing a biological basis for ronde - cel's durable responses , including enhanced memory potential of cytotoxic effector cells from CD62L + enrichment and CD19 / CD20 dual - targeting to overcome low antigen expression . The PINACLE pivotal single - arm trial , a seamless expansion of the 3L + cohort in the Phase 1/2 multi - cohort trial , is ongoing . Additional data from this trial are expected in the second half of 2026 , and pivotal data are expected in mid - 2027 with submission of a Biologics License Application ( BLA ) to the FDA expected to follow in the second