DISP-10 Phase I Dosing: Novel Virus-CAR-T Mechanism Meets Maximum Development Uncertainty in Solid Tumors

Dispatch Bio Doses First Patient in Phase I GI Cancer Trial

Dispatch Bio has initiated a Phase I clinical trial, dosing the first patient with its investigational immunotherapy, DISP-10, for advanced gastrointestinal (GI) cancers. The multi-component therapy, which includes an engineered virus (DV-10) and Bristol Myers Squibb’s ide-cel, aims to address the limitations of current immunotherapies for solid tumors. DISP-10 has received Fast Track designation from the US FDA, underscoring its potential to meet an urgent medical need in indications like colorectal cancer.

• The ongoing Phase I, multicentre, open-label study is evaluating the safety, tolerability, and preliminary efficacy of DISP-10 in adults with advanced GI cancers, specifically colorectal, gastric, oesophageal, and gastroesophageal adenocarcinomas. The first participant has successfully completed the dose-limiting toxicity assessment according to the study’s protocol.
• DISP-10 is a novel immunotherapy comprising two main parts: DV-10, a virus engineered to deliver a modified B cell maturation antigen (BCMA), Interleukin-18 (IL-18), and C-X-C motif chemokine ligand 9 (CXCL9) to alter tumor cells and enhance T cell activity; and ide-cel, a chimeric antigen receptor (CAR) T cell therapy from Bristol Myers Squibb, though ide-cel is not approved for solid tumors independently.
• The US FDA has granted Fast Track designation to DISP-10 for advanced GI cancers, highlighting the urgent need for new treatments. Dispatch Bio aims to overcome longstanding challenges in solid tumor immunotherapy, such as the lack of safe and homogeneously expressed target antigens, narrow therapeutic windows, and inhibitory tumor microenvironments, particularly in conditions like colorectal cancer, a primary cause of death in individuals aged under 50 years.

Defining Success: Key Endpoints in Advanced GI Cancer Trials

Clinical trials in advanced gastrointestinal (GI) cancers utilize a hierarchy of endpoints to capture both survival benefit and treatment activity, with endpoint selection varying by disease stage, treatment setting, and therapeutic modality. The field continues to debate the surrogacy relationships between these measures, particularly as the correlation between progression-free and overall survival has proven inconsistent across tumor types and lines of therapy.

• Overall Survival (OS): Defined as the time from randomization to death from any cause, OS is consistently regarded as the gold-standard primary endpoint for treatment effect assessment in gastric cancer and other advanced GI malignancies, given its clinical interpretability and freedom from measurement bias.

• Progression-Free Survival (PFS): PFS remains the endpoint of choice in most first-line metastatic colorectal cancer trials; however, analyses have demonstrated that it is no longer a validated surrogate for OS in this setting, raising questions about its use as a standalone primary endpoint in first-line colorectal cancer studies.

• Event-Free Survival (EFS): In neoadjuvant trials of gastric and gastroesophageal junction adenocarcinoma, EFS has shown strong trial-level correlation with OS (R² = 0.826), supporting its potential utility as a surrogate primary endpoint in neoadjuvant randomized controlled trial designs.

• Disease-Free Survival (DFS): Applied predominantly in adjuvant chemotherapy settings for gastric cancer, 3-year DFS is a commonly reported primary efficacy parameter and an accepted surrogate endpoint for OS in adjuvant randomized controlled trials.

• Objective Response Rate (ORR) and Disease Control Rate (DCR): ORR — the proportion of patients achieving complete or partial response per RECIST 1.1 — is frequently employed as a primary or co-primary endpoint in targeted therapy trials (e.g., 38% ORR reported in the MOUNTAINEER trial for HER2-positive colorectal cancer). DCR, which additionally captures stable disease, provides a broader measure of disease containment.

• Duration of Response (DOR), Time to Treatment Failure (TTF), and Time to Treatment Discontinuation (TTD): These secondary endpoints collectively characterize the durability and tolerability of treatment benefit, with TTF and TTD offering particular relevance for real-world effectiveness assessments. Notably, only substantial PFS effects are considered likely to translate into clinically meaningful outcomes in advanced GI cancers.

Overcoming Treatment Hurdles in Advanced GI Cancers

Advanced gastrointestinal (GI) cancers present a formidable therapeutic landscape, where late-stage diagnosis, tumor biology complexity, and systemic treatment limitations converge to constrain clinical outcomes. Despite advances in targeted therapy and immunotherapy, durable responses remain elusive for the majority of patients, underscoring the need to critically understand the barriers inherent to current treatment paradigms.

• Diagnostic and biomarker deficiencies: Most GI cancers are diagnosed at advanced metastatic stages due to the absence of reliable early-detection biomarkers. Existing diagnostic biomarkers demonstrate inadequate specificity and sensitivity, directly limiting opportunities for timely therapeutic intervention.

• De novo and acquired treatment resistance: Both primary and acquired resistance to targeted therapies are driven by intratumor heterogeneity and clonal evolution. Resistance mechanisms frequently involve mutation of the drug target itself or aberrant activation of pathways upstream, downstream, or parallel to the targeted node. For systemic chemotherapies, the identification of discrete, recurrent resistance-conferring genetic aberrations remains elusive, partly due to the broad mutagenic effects of these agents.

• Compensatory signaling and intrinsic resistance: The full therapeutic potential of molecularly targeted agents is undermined by compensatory signaling pathways that confer intrinsic resistance, as well as by acquired resistance emerging through clonal selection under treatment pressure.

• Immunotherapy efficacy limitations: Despite notable advances in cancer immunotherapy, objective responses occur in only approximately 20% of patients. The immunosuppressive tumor microenvironment — particularly in pancreatic ductal adenocarcinoma (PDAC), where regulatory T cells (Tregs), tumor-associated macrophages (TAMs), and myeloid-derived suppressor cells (MDSCs) collectively suppress CD8⁺ T-cell–mediated tumor recognition — represents a primary driver of resistance to checkpoint inhibitors and cancer vaccines.

• Desmoplasia and impaired drug delivery in PDAC: The dense desmoplastic stroma characteristic of pancreatic ductal adenocarcinoma physically isolates tumor cells within an extensive fibrotic reaction, severely impairing drug delivery. This stromal compartment also serves as the primary source of cytokines and chemokines that facilitate rapid, occult tumor progression.

• Treatment toxicity and dosing constraints: Treatment-induced toxicity frequently precludes the use of continuous, pharmacodynamically effective dosing, necessitating intermittent scheduling strategies. Distinct safety profiles across regimens — such as hepatic arterial infusion chemotherapy combinations — further require individualized toxicity management.

• Patient stratification complexity: The lack of robust prognostic and predictive biomarkers hampers risk-adapted treatment selection. Integration of multiomic datasets for patient stratification remains a significant challenge, with machine-learning–based data integration tools still in development and not yet broadly implemented in clinical practice.

DISP-10's Place in the Combination Therapy Landscape for GI Cancers

Recent clinical trials have explored a broad spectrum of combination strategies in advanced gastrointestinal cancers, spanning immune checkpoint inhibition, targeted molecular therapy, anti-angiogenic agents, and dual-pathway blockade. These approaches are being evaluated across gastric/gastroesophageal junction (GEJ), pancreatic, and colorectal cancers, with efficacy signals emerging across multiple biomarker-selected and unselected populations.

Pioneering a New Frontier for CAR-T in Solid Tumors

The initiation of a Phase I trial for DISP-10 in advanced gastrointestinal cancers signals an ambitious push to extend the transformative power of CAR-T cell therapy beyond hematologic malignancies. While CAR-T cells have delivered remarkable outcomes in diseases like multiple myeloma, as seen with ide-cel's approval for relapsed/refractory patients, their journey into solid tumors has been fraught with challenges. The dense, immunosuppressive tumor microenvironment, poor T-cell trafficking, and heterogeneous antigen expression in solid tumors have historically blunted CAR-T efficacy.

Dispatch Bio's strategy with DISP-10 is to tackle these barriers head-on by combining an engineered oncolytic virus (OV) with ide-cel. Research indicates that OVs can act as multi-faceted agents: directly lysing tumor cells, releasing tumor antigens, and crucially, reprogramming the tumor microenvironment to be more permissive for CAR-T infiltration and survival. Some studies even explore OVs as vectors to deliver novel CAR targets to tumor cells, effectively 'painting' the tumor for CAR-T recognition. This innovative approach, bolstered by a Fast Track designation, highlights the urgent unmet medical need in GI cancers like colorectal cancer, where conventional therapies have reached a plateau.

However, the path forward is not without its complexities. CAR-T therapies carry a known safety profile, including risks of cytokine release syndrome, neurotoxicity, and prolonged cytopenias, as evidenced by real-world data for ide-cel. Combining this with an oncolytic virus introduces new variables, and careful monitoring for altered or exacerbated toxicities will be paramount. Furthermore, ensuring effective delivery and replication of the oncolytic virus within the challenging gastrointestinal environment, where degradation and immune neutralization are concerns, remains a critical hurdle. Despite these challenges, this trial represents a significant step towards a new era of precision immunotherapy for solid tumors, potentially paving the way for more effective treatments by synergistically leveraging the strengths of both oncolytic viruses and CAR-T cells.