A2 Biotherapeutics, Inc. (A2 Bio), a clinical-stage immunotherapy company developing first-in-class logic-gated therapies for solid tumors, today announced the presentation of safety and efficacy data from the ongoing EVEREST-2 clinical study (NCT06051695). The findings, which are being presented in poster presentations during the 2026 Annual Meeting of the American Society of Clinical Oncology (ASCO) taking place May 29 – June 2, 2026, in Chicago, include updates on the first reported complete response (CR) in a patient with non-small cell lung cancer (NSCLC) following treatment with A2B694, a logic-gated mesothelin (MSLN)-targeted TmodTM chimeric antigen receptor T-cell (CAR T-cell) therapy.
Complete responses have rarely been observed in studies of CAR T-cell therapies for the treatment of solid tumors, and to date none has been reported in patients with lung cancer.1
“We are encouraged by the EVEREST-2 study data being presented during ASCO 2026, including updated results for the first reported complete response to CAR T-cell therapy in a patient with a hard-to-treat case of non-small cell lung cancer. These findings support the potential for logic-gated therapies, such as A2B694, to treat solid tumors. We eagerly await the results from A2B543, the armored version of A2B694, which has the potential for greater potency without compromising safety,” said Salman R. Punekar, M.D., assistant professor of medicine, NYU Langone Health, Perlmutter Cancer Center and treating physician of the patient.
EVEREST-2 Study Arm 1: Efficacy and Safety Update for A2B694
As of January 5, 2026, 13 patients were enrolled in phase 1: eight women and five men, with a median age of 59 years; 11 were non-Hispanic White and two were Hispanic/unknown race. Tumor types included ovarian (n = 3), pancreatic (n = 3), NSCLC (n = 1), colorectal (n = 4), gastro-esophageal (n = 1), and mesothelioma (n = 1). A2B694 dose groups were 1×108 (n = 3), 2×108 (n = 4), 4×108 (n = 5), and 6×108 plus low-dose IL-2 (n = 1) cells.
Lymphodepletion prior to administration of A2B694 was well-tolerated by all patients, with expected transient cytopenias. All patients had at least one adverse event; all adverse event terms were reported in one patient each, except for grade 3 neutropenia, which was reported in two patients. One patient had grade 3 ICANS managed with corticosteroids and one patient had grade 1 CRS confounded by IL-2 administration. There were no dose-limiting toxicities or new safety signals after up to 17 months of follow-up. No deaths were attributed to A2B694, and no patient has discontinued the study due to adverse events.
One patient with co-mutated (KRAS G12V/STK11) NSCLC, a subtype associated with resistance to chemoimmunotherapy and poor prognosis, had progressed on standard-of-care first-line treatment of carboplatin, pemetrexed, and pembrolizumab before enrolling in EVEREST-2. At month 3 post-infusion of A2B694, the patient achieved a complete response (CR) per RECIST 1.1 and had a confirmed CR by central review at month 6 as well as a PET-CT scan which showed no evidence of disease. At month 8, the patient had an isolated CNS relapse, with an ongoing non-CNS CR per Response Assessment in Neuro-Oncology Brain Metastases (RANO-BM) at month 9. At 15 months, the patient’s CT showed no new findings, and persistence of A2B694 in the blood was confirmed by ddPCR.
EVEREST-2 Study Arm 2: Enrollment Update on A2B543
An additional presentation from the EVEREST-2 study is a trials-in-progress poster about A2B543, a CAR T-cell therapy which uses the same logic-gated construct as A2B694, armored with the addition of a membrane-tethered IL-12 (mem-IL-12) booster.
IL-12 is a potent, pro-inflammatory cytokine that plays a crucial role in inducing antitumor immune responses; however, systemic IL-12 can be prohibitively toxic. In A2B543, expression of the mem-IL-12 cassette is under the control of an NFAT promoter and is induced during antigen engagement or T cell activation. This inducible mem-IL-12 is designed to reduce the toxicity associated with systemic IL-12 while enhancing the long-term potency and persistence of TmodTM. The first A2B543 patient was enrolled to dose level 1 in January 2026, and dose escalation continues. A2B543 has received Fast Track Designation from the FDA.
A third A2 Bio poster presentation during ASCO 2026 describes modules based on IL-12 and other molecules that boost potency and preserve selectivity of TmodTM-based precision cell therapies.
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Poster Presentation Details |
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Abstract Title |
Presenting Author |
Abstract Number |
Poster Board Number |
Poster Presentation Date/Time |
Poster Session |
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Initial safety and efficacy of A2B694, a logic-gated mesothelin (MSLN)-targeted Tmod chimeric antigen receptor T-cell (CAR T) therapy in patients with advanced solid tumors with HLA-A*02 loss of heterozygosity (LOH) |
Mayo Clinic |
8579 |
369 |
Sunday, May 31, 2026
9:00 AM-12:00 PM CDT |
Lung Cancer—Non- Small Cell Metastatic |
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A logic-gated chimeric antigen receptor T-cell (CAR T) therapy with an armored, membrane-tethered IL-12 booster in patients with advanced solid tumors with HLA-A*02 loss of heterozygosity (LOH): EVEREST-2, a Phase 1/2 study |
NYU Langone Health |
TPS2673 |
459a |
Saturday, May 30, 2026
1:30 PM-4:30 PM CDT |
Developmental Therapeutics— Immunotherapy |
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Influence of onboard, tethered IL-12 on potency of the Tmod NOT gate and selectivity |
Jushen Liang
A2 Biotherapeutics |
2562 |
352 |
Saturday, May 30, 2026
1:30 PM-4:30 PM CDT |
Developmental Therapeutics— Immunotherapy |
Full abstracts are available online on the ASCO website.
About EVEREST-2
The EVEREST-2 master protocol (NCT06051695) is a seamless Phase 1/2 study evaluating the safety and efficacy of A2B694 (Arm 1) and A2B543 (Arm 2), autologous logic-gated investigational cell therapies developed from the A2 Bio proprietary Tmod™ platform. The Tmod™ platform provides selective killing of tumor cells and protection of normal cells via a dual-receptor design consisting of an activator that targets tumor cells and a blocker that protects normal cells. A2B694 consists of an activator that targets MSLN and a blocker that targets HLA-A*02. HLA-A*02 is lost in tumor cells and present in normal cells in the eligible patient population. A2B543 contains the same Tmod™ construct as A2B694 with an added mem-IL-12 booster. The EVEREST-2 study is recruiting patients with colorectal cancer, pancreatic cancer, non-small cell lung cancer, ovarian cancer, mesothelioma, and other solid tumors that express MSLN and have lost HLA-A*02 expression.
About the Tmod™ Platform
Invented at A2 Bio, the TmodTM platform is a precision-targeting cellular system, designed with logic-gate technology to enable immune cells to unequivocally differentiate tumors from normal tissues. The system consists of activator and blocker receptors. The activator recognizes antigens on tumor cells and triggers their destruction, while the blocker recognizes antigens on normal cells and protects them. This novel blocker technology enables precise, personalized, and effective T-cell targeting specifically against tumors.
For more information about A2 Bio clinical studies and how to enroll, visit www.a2bioclinicaltrials.com.
About A2 Bio
A2 Biotherapeutics, Inc. (A2 Bio) is a clinical-stage biotech company developing first-in-class logic-gated cell therapies to address the high unmet need in cancers. A2 Bio invented the proprietary Tmod™ cell therapy platform to tackle the fundamental challenge in cancer treatment—the ability of cancer medicines to distinguish between tumor and normal cells. For more information, visit the company’s website at www.a2bio.com.
Reference
1 Escobar G, Berger TR, Maus MV. CAR-T cells in solid tumors: Challenges and breakthroughs. Cell Rep Med. 2025;102353.
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