Tempest Therapeutics, a clinical-stage biotechnology company based in Brisbane, California, has announced positive interim results from its ongoing REDEEM-1 trial of TPST-2003, a novel CD19/BCMA dual-targeting CAR-T therapy for patients with relapsed or refractory multiple myeloma (rrMM). As of January 31, 2026, a total of 36 patients had received one infusion of TPST-2003, with 24 patients enrolled in a prior Phase 1/2 investigator-initiated trial (IIT) and 12 patients in the ongoing REDEEM-1 trial. These findings represent one of the largest datasets evaluating a dual-targeting CAR-T therapy for rrMM.

Strong Efficacy Across All Dose Levels

All six patients currently evaluable for efficacy in the REDEEM-1 trial—three at dose level 1 (1 x 106 cells/kg) and three at dose level 2 (2 x 106 cells/kg)—achieved a complete response (CR) according to the International Myeloma Working Group (IMWG) uniform response criteria. Among 25 evaluable patients with measurable disease at baseline across both the IIT and REDEEM-1 trials, the overall response rate (ORR) was 100% (25/25).

Tempest emphasized that clinical responses were consistent across all dose levels and study settings, supporting the reproducibility of TPST-2003’s parallel dual-targeting CAR architecture. The company plans to present the results of the REDEEM-1 trial and updated results from the IIT at a scientific meeting later this year.

Favorable Safety Profile Across Dose Levels

As of January 15, 2026, TPST-2003 demonstrated a favorable safety profile across all dose levels evaluated in the REDEEM-1 trial. No patients experienced Grade 3 or higher cytokine release syndrome (CRS), and only one patient treated at the highest dose level (3 x 106 cells/kg) experienced low-grade immune effector cell-associated neurotoxicity syndrome (ICANS). No Grade 3 or higher ICANS was reported.

The observed safety profile, combined with the consistent responses in the trial, supports Tempest’s plan to accelerate its development timeline and meet with the U.S. Food and Drug Administration (FDA) to discuss initiating a U.S. registrational study later this year.

Deep Responses and Durable Disease Control

Tempest stated that the results of the ongoing REDEEM-1 study are consistent with prior clinical results from the 24-patient Phase 1/2 IIT. In the IIT, among 19 evaluable patients with measurable disease at baseline, the ORR was 100% (19/19), with a CR rate of 89.5% (17/19). At the highest dose level, CR was achieved in all five patients (100%).

The IIT also demonstrated durable disease control, with a median progression-free survival (PFS) of 23.1 months across all patients and 23.1 months in patients with extramedullary disease (EMD). All five evaluable patients remained minimal residual disease (MRD)-negative at month 12, according to the company.

Patients with EMD are often associated with worse outcomes and shorter disease control in rrMM. Tempest believes these findings support continued evaluation of TPST-2003 for its potential to deliver both deep and durable responses in advanced disease.

TPST-2003 incorporates a proprietary parallel dual-targeting CAR architecture designed by Tempest’s partner, Novatim Immune Therapeutics. This structure is intended to address tumor heterogeneity and antigen escape, mechanisms believed to contribute to disease progression following currently available therapies.

Tempest’s parallel CAR architecture is also being applied to other programs, including TPST-3003, an allogeneic CD19/BCMA dual-targeting CAR-T therapy under development for rrMM, and TPST-4003, an in vivo CD19/BCMA dual-targeting CAR-T therapy under development for systemic lupus erythematosus (SLE) and other immunology disorders. The company expects initial clinical data from both programs later this year.

Tempest plans to present the complete results from the ongoing Phase 1/2a REDEEM-1 study, as well as updated data from the Phase 1/2 IIT, in 2026. Based on data generated to date, the company intends to submit a U.S. Investigational New Drug (IND) application and, subject to clearance, initiate a U.S. registrational study of TPST-2003 in 2026.

According to the company, approved CAR-T therapies have demonstrated meaningful clinical benefit in patients with rrMM and represent an important treatment option in later lines of therapy. However, relapse remains common, and treatment can be associated with toxicity management challenges and manufacturing constraints.

Tempest’s approach with TPST-2003 is designed to address these limitations by targeting two antigens simultaneously—CD19 and BCMA—potentially reducing the risk of resistance mechanisms and improving treatment outcomes.