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EX-99.1

2 lyel-20260506x8kexx991.htm

EX-99.1

Document

Exhibit 99.1

Lyell Immunopharma Reports Business Highlights and Financial Results for the First Quarter 2026

•PiNACLE pivotal clinical trial evaluating ronde-cel in patients with LBCL in third- or later-line setting on track to report additional data in second half of 2026, with pivotal data expected mid-2027 and BLA submission expected to follow in 2027

•PiNACLE-H2H, a first of its kind Phase 3 clinical trial evaluating ronde-cel head-to-head against standard-of-care CD19 CAR T-cell therapies in the LBCL second-line setting, commenced patient dosing

•Phase 1 clinical trial of LYL273 continues to enroll patients with metastatic colorectal cancer, with commencement of patient dosing at Dose Level 3

•Closed second $50 million tranche of $100 million private placement at $25.61 per share, with approximately $261 million in cash as of March 31, 2026, expected to provide runway into Q3 2027

SOUTH SAN FRANCISCO, Calif., May 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 first quarter ended March 31, 2026.

First Quarter Updates and Recent Business Highlights

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 with a true ‘OR’ logic gate to target B cells that express either CD19 or CD20 with full potency 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) designation in the third- and later-line (3L+) and second-line (2L) settings, as well as Fast Track designation for the treatment of adults with relapsed/refractory large B-cell lymphoma (R/R LBCL). Two pivotal trials for ronde-cel in LBCL are underway.

•The ongoing 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 2027. The primary endpoint of the trial is the overall response rate, including an evaluation of duration of response.

•In February 2026, patient dosing commenced in PiNACLE-H2H, the first-of-its-kind Phase 3 randomized controlled trial evaluating ronde-cel versus investigator’s choice of axicabtagene ciloleucel or lisocabtagene maraleucel in patients with R/R LBCL in the 2L setting. The trial’s primary endpoint is event-free survival.

LYL273: A next-generation guanylyl cyclase C (GCC)-targeted CAR T-cell product candidate for the treatment of metastatic colorectal cancer (mCRC) and other GCC-expressing cancers

LYL273 is a GCC-targeted CAR T-cell product candidate enhanced with CD19 CAR expression and controlled cytokine release, designed to improve CAR T-cell expansion, immune cell infiltration and cancer cell killing in the hostile solid tumor microenvironment. In November 2025, Lyell acquired global rights (excluding mainland China, Hong Kong, Macau and Taiwan) to LYL273, which has shown promising dose-dependent clinical activity in patients with advanced mCRC in a Phase 1 trial conducted in the U.S. following proof of concept in 15 patients in China. The FDA granted LYL273 Fast Track designation for the treatment of mCRC.

•The U.S. Phase 1 clinical trial is continuing to enroll patients to determine the recommended Phase 2 dose. In March 2026, dosing commenced at Dose Level 3 (3 x 106 CAR T cells/kg). A data update focused on safety from this trial is expected in the first half of 2026, with a second data update including clinical outcomes expected in the second half of 2026.

Additional Business Highlights

•In March 2026, Lyell closed the second $50 million tranche of its July 2025 equity private placement, following the successful achievement of a clinical milestone in PiNACLE. In the second tranche of the financing, which completed the total $100 million private placement, shares of common stock were sold at a purchase price of $25.61 per share.

•In March 2026, Smital Shah was appointed Chief Financial and Business Officer.

First Quarter 2026 Financial Results

Lyell reported a net loss of $24.2 million for the first quarter ended March 31, 2026, compared to a net loss of $52.2 million for the same period in 2025. The $28.0 million decrease in net loss was primarily due to a $17.

lyel-202603120001806952false00018069522026-03-122026-03-12

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): March 12, 2026

Lyell Immunopharma, Inc. (Exact name of Registrant as Specified in Its Charter)

Delaware001-4050283-1300510 (State or Other Jurisdiction of Incorporation)(Commission File Number)(IRS Employer Identification No.)

201 Haskins Way South San Francisco, California 94080 (Address of Principal Executive Offices)(Zip Code)

Registrant’s Telephone Number, Including Area Code: 650 695-0677 (Former Name or Former Address, if Changed Since Last Report) Not Applicable

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

oWritten communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

oSoliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

oPre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

oPre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each classTrading Symbol(s)Name of each exchange on which registered Common Stock, $0.0001 par value per shareLYELNASDAQ Global Select Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter). Emerging growth company o If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. o

Item 2.02 Results of Operations and Financial Condition. On March 12, 2026, Lyell Immunopharma, Inc. (the “Company”) issued a press release announcing its financial results for the quarter and full year ended December 31, 2025. A copy of the press release is attached hereto as Exhibit 99.1. The information in this Item 2.02, including the attached Exhibit 99.1, is being furnished and shall not be deemed “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference into any filing made by the Company under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such a filing.

Item 9.01 Financial Statements and Exhibits. (d) Exhibits

Exhibit NumberDescription

99.1Press Release Dated March 12, 2026

104Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

Lyell Immunopharma, Inc.

Date:March 12, 2026By:/s/ MARK MELTZ Mark Meltz General Counsel and Corporate Secretary