TPST

EX-99.1

2 tpst-ex99_1.htm

EX-99.1

EX-99.1

Exhibit 99.1

Tempest Reports Second Quarter 2026 Financial Results and

Provides Business Update

Executed a development collaboration with Senlang Biotechnology to advance certain in vivo CAR-T product candidates, including TPST-4003, a CD7-targeted next-generation in vivo CAR-T, with first patient dosing anticipated in the fourth quarter of 2026 and initial clinical data expected in the first half of 2027

Unveiled pipeline of next-generation in vivo CAR-T product candidates for oncology and immunology applications differentiated by CD-7 targeted mRNA/LNP delivery approach

Appointed Drake Richey and John Yee, MD, MPH, to Board of Directors

Brisbane, CA, August 13, 2026 – Tempest Therapeutics, Inc. (Nasdaq: TPST) (“Tempest”), a clinical-stage biotechnology company developing a pipeline of advanced chimeric antigen receptor T-cell (“CAR-T”) product candidates, today reported financial results for the quarter ended June 30, 2026, and provided a business update.

“We continue to execute against our strategy by advancing our next-generation in vivo CAR-T platform, expanding our expertise with the appointment of two new board members and strengthening our development capabilities through a new collaboration focused on our next-generation in vivo CAR-T candidate, TPST-4003,” said Matt Angel, Ph.D., President and Chief Executive Officer of Tempest. “These milestones reflect the momentum we are building across the business and reinforce our commitment to developing innovative therapies aiming to transform patient care. We are particularly excited to advance TPST-4003 toward an investigator-initiated clinical trial planned for the fourth quarter of 2026, an important step as we work to bring transformative options to patients.”

Recent Highlights

•

TPST-4003

• Unveiled next-generation in vivo CAR-T pipeline, including lead product candidate TPST-4003, a dual-targeting CD19/BCMA CAR-T that combines the company’s proprietary CD7-targeted mRNA/LNP delivery with its clinically validated dual-target CAR architecture for broad B-cell lineage depletion and reset.

• Executed a strategic partnership with Hebei Senlang Biotechnology to collaborate on the development of Tempest’s certain proprietary in vivo CAR-T product candidates, including its CD7-targeted next-generation in vivo CAR-T product candidate, TPST-4003, beginning with an investigator-initiated trial

in China evaluating TPST-4003 in approximately 10 patients with myasthenia gravis or multiple sclerosis. The company expects first patient enrollment and dosing to occur in the fourth quarter of 2026.

•

TPST-2003

• Reported positive interim results across two ongoing clinical trials (REDEEM-1 Phase 1/2a trial of TPST-2003 in patients with relapsed/refractory multiple myeloma (“rrMM”), and POEMS-1 Phase 1 trial evaluating TPST-2003 in the rare disease, POEMS syndrome), both of which are being sponsored and conducted by Tempest’s partner, Novatim Immune Therapeutics:

• 100% complete response rate among all 15 CAR-T-naïve efficacy evaluable patients treated with TPST-2003 across REDEEM-1 and POEMS-1 trials.

• Favorable safety profile with no Grade ≥3 cytokine release syndrome or immune effector cell-associated neurotoxicity syndrome in REDEEM-1 trial appears to be emerging as a potentially differentiating attribute in its class.

• Prior investigator-initiated trial reached median progression free survival of 23.1 months, including in patients with extramedullary disease.

• 44 patients with rrMM treated to date across three studies.

• Announced the selection of Cincinnati Children’s AGCTC as the lead contract development and manufacturing partner to conduct the formal technology transfer of TPST-2003, Tempest’s dual-targeting CD19/BCMA CAR-T therapy under development for the treatment of relapsed/refractory multiple myeloma (rrMM). Further to the selection of AGCTC as lead partner, AGCTC took delivery of the TPST-2003 lentiviral vector, a critical component used in the manufacturing of TPST-2003, supporting plans to initiate the first potentially registrational study to evaluate a dual-targeting CAR-T therapy in patients with rrMM, including patients who are experiencing extramedullary disease (EMD), later this year.

• Corporate:

• Entered into a definitive agreement for the inducement of exercise of certain outstanding warrants (“Warrant Inducement”) for approximately $2 million in gross proceeds.

• Appointed two independent directors, Drake Richey and John Yee, MD, MPH, collectively bringing decades of experience in corporate finance and therapeutic product development to Tempest’s Board of Directors.

• Announced the appointment of Andrew Fang, Ph.D., as Head of Business Development. In his role, Dr. Fang will lead Tempest’s global business development efforts, including strategic partnerships, cross-border licensing and corporate transactions, with a particular focus on expanding Tempest’s outreach and par

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