8-K: Tempest's TPST-2003 Achieves 100% CR in Myeloma Trial

Tempest Therapeutics announced compelling interim results from its REDEEM-1 trial for TPST-2003, a dual-targeting CAR-T therapy, showing a 100% complete response rate in evaluable patients with relapsed/refractory multiple myeloma.

Summary

• Interim results from the REDEEM-1 Phase 1/2a trial evaluating TPST-2003, a CD19/BCMA dual-targeting CAR-T therapy for relapsed/refractory multiple myeloma (rrMM), were announced.
• All six efficacy-evaluable patients in the REDEEM-1 trial achieved a 100% complete response (CR) rate according to IMWG criteria.
• Across both the REDEEM-1 trial and a prior 24-patient Phase 1/2 investigator-initiated trial (IIT), the overall response rate (ORR) was 100% (25/25) among evaluable patients with measurable disease at baseline.
• TPST-2003 demonstrated a favorable safety profile in REDEEM-1 with no Grade >3 cytokine release syndrome (CRS) and no Grade >3 immune effector cell-associated neurotoxicity syndrome (ICANS).
• The prior IIT showed durable disease control with a median progression-free survival (PFS) of 23.1 months across all patients, including those with extramedullary disease (EMD), and all evaluable patients remained MRD-negative at month 12 (5/5).
• Tempest plans to submit a U.S. IND application and, subject to clearance, initiate a U.S. registrational study for TPST-2003 in 2026.
• The company is exploring potential development of TPST-2003 to include patients with large B-cell lymphoma (LBCL) and other related indications.
• Tempest also has TPST-3003 (allogeneic CD19/BCMA CAR-T for rrMM) and TPST-4003 (in vivo CD19/BCMA CAR-T for systemic lupus erythematosus and other immunology disorders) in its pipeline, with initial clinical data expected later in 2026.

Sentiment

Score: 9

Explanation: StockSavvy.ai views this as a highly positive announcement due to the exceptional clinical efficacy data (100% CR, 100% ORR, durable PFS) and favorable safety profile of TPST-2003, which positions it as a potential class-leading therapy in a challenging disease area.

Positives

• 100% complete response (CR) rate among all six efficacy evaluable patients in the REDEEM-1 trial.
• Overall response rate (ORR) of 100% (25/25) across both studies for evaluable patients with measurable disease at baseline.
• Favorable safety profile observed across all dose levels in REDEEM-1, with no Grade >3 CRS or ICANS.
• Prior IIT demonstrated durable disease control with a median progression-free survival (PFS) of 23.1 months, including in patients with extramedullary disease (EMD), which is often associated with worse outcomes.
• All evaluable patients in the IIT remained MRD-negative at month 12 (5/5).
• The parallel dual-targeting CAR structure is designed to address tumor heterogeneity and antigen escape, mechanisms believed to contribute to disease progression following currently available therapies.
• Decision to accelerate the development timeline for TPST-2003, with plans for a U.S. registrational study in 2026.
• Exploration of TPST-2003 for additional indications like large B-cell lymphoma (LBCL) and other related indications.

Negatives

• One patient treated at the highest dose level (3 x 10^6 cells/kg) in REDEEM-1 experienced low-grade immune effector cell-associated neurotoxicity syndrome (ICANS).
• Approved CAR-T therapies, while beneficial, still face challenges with relapse, toxicity management, and manufacturing constraints, indicating that TPST-2003 aims to overcome these but is not without its own development hurdles.

Risks

• Need for additional capital to fund planned programs and operations and to continue to operate as a going concern.
• Unexpected safety or efficacy data observed during preclinical or clinical trials.
• Possibility that results from prior clinical trials and preclinical studies may not necessarily be predictive of future results.
• Past results may not be indicative of future results.
• Clinical trial site activation or enrollment rates that are lower than expected.
• Loss of key personnel.
• Changes in expected or existing competition.
• Changes in the regulatory environment.
• Risks relating to volatility and uncertainty in the capital markets for biotechnology companies.
• Unexpected litigation or other disputes.

Future Outlook

Tempest Therapeutics plans to submit a U.S. IND application and, subject to clearance, initiate a U.S. registrational study for TPST-2003 in 2026. The company is also exploring the development of TPST-2003 for large B-cell lymphoma and other related indications. Initial clinical data for TPST-3003 and TPST-4003, other CAR-T programs, are expected later in 2026.

Management Comments

• "These results have the potential to raise the bar for clinical effect in relapsed/refractory multiple myeloma (rrMM)." Dr. Matt Angel, President and Chief Executive Officer of Tempest.
• "The data from the ongoing REDEEM-1 trial suggest a favorable safety and efficacy profile that could set TPST-2003 apart from currently approved CAR-T therapies and offer a safe, effective option for patients with rrMM." Dr. Matt Angel.
• "We believe that replicating these results in the remainder of the REDEEM-1 trial and also in a registrational trial would position TPST-2003 as a class-leading therapy for rrMM, and we have therefore made the decision to accelerate our development of TPST-2003." Dr. Matt Angel.
• "The differentiated parallel structure of TPST-2003s dual-targeting CAR is designed to address the challenges of relapse and suboptimal efficacy of other approaches." Guoxiang Wu, M.D., Chairman and General Manager of Novatim.
• "TPST-2003 has shown compelling efficacy results in rrMM and POEMS syndrome. In particular, we believe the favorable safety profile of TPST-2003 supports its potential in additional indications including autoimmune diseases and may provide broader clinical benefits for patients worldwide." Guoxiang Wu, M.D.

Industry Context

StockSavvy.ai notes that the CAR-T therapy landscape for relapsed/refractory multiple myeloma is competitive, with several approved therapies demonstrating significant benefit but also facing challenges related to relapse, toxicity, and manufacturing. TPST-2003's dual-targeting CAR structure aims to address tumor heterogeneity and antigen escape, which are key mechanisms of resistance to existing single-target CAR-T therapies. The favorable safety profile and high complete response rates, if sustained, could position TPST-2003 as a differentiated and potentially class-leading option, especially given the exploration into broader indications like large B-cell lymphoma and autoimmune diseases.

Comparison to Industry Standards

• Approved CAR-T therapies for rrMM, such as Abecma (idecabtagene vicleucel) and Carvykti (ciltacabtagene autoleucel), have demonstrated high response rates but often face issues with durability, antigen escape, and toxicity (e.g., higher grades of CRS and ICANS).
• TPST-2003's 100% CR rate in evaluable patients and median PFS of 23.1 months in the IIT, including EMD patients, appear highly competitive. For instance, Carvykti's CARTITUDE-1 trial showed a 98% ORR and 83% sCR rate, with a median PFS of 33.9 months. Abecma's KarMMa trial showed a 73% ORR and 33% CR rate, with a median PFS of 8.8 months. TPST-2003's safety profile, with no Grade >3 CRS or ICANS, could represent an improvement over some existing therapies which can have significant toxicity profiles.
• The dual-targeting approach of TPST-2003 (CD19/BCMA) directly addresses tumor heterogeneity and antigen escape, which are known limitations of single-target CAR-T therapies like those targeting only BCMA.

Stakeholder Impact

• Shareholders: Positive impact due to strong clinical data, potential for accelerated development, and expansion into new indications, which could increase company valuation.
• Patients with rrMM: Significant positive impact, as TPST-2003 offers a potentially highly effective and safer treatment option for a severe, relapsed/refractory condition.
• Employees: Positive impact from successful clinical progress and accelerated development, potentially leading to increased job security and growth opportunities.
• Regulatory Authorities: Will be closely monitoring the registrational study given the promising interim data.

Next Steps

• Present complete results from the ongoing Phase 1/2a REDEEM-1 study and updated data from the Phase 1/2 IIT at a scientific meeting in 2026.
• Submit a U.S. IND application for TPST-2003.
• Initiate a U.S. registrational study of TPST-2003 in 2026, subject to IND clearance.
• Explore potential development of TPST-2003 for large B-cell lymphoma (LBCL) and other related indications.
• Expect initial clinical data from TPST-3003 (allogeneic CD19/BCMA CAR-T) and TPST-4003 (in vivo CD19/BCMA CAR-T) later in 2026.

Key Dates

Recommendation

The interim clinical data for TPST-2003 is exceptionally strong, demonstrating a 100% complete response rate and a favorable safety profile in a difficult-to-treat patient population (relapsed/refractory multiple myeloma). The decision to accelerate development and pursue a U.S. registrational study in 2026, coupled with exploration into additional indications, signals high confidence from management and significant market potential. While risks inherent to clinical development and the need for future capital exist, the current data suggests a potentially transformative therapy that could significantly enhance the company's value.

Keywords

Tempest Therapeutics, TPST, CAR-T therapy, multiple myeloma, relapsed/refractory multiple myeloma, rrMM, CD19/BCMA, REDEEM-1, clinical trial, complete response, progression-free survival, biotechnology, oncology, cell therapy, IND application, registrational study, Novatim Immune Therapeutics