T cell engagers have helped reshape treatment in some blood cancers, but translating that success into solid tumors remains one of oncology’s more difficult challenges.
Solid tumors represent roughly 90% of adult human cancers. Yet the biology of solid tumors, including antigen heterogeneity, antigen loss, on-target/off-tumor toxicity risks and an immunosuppressive tumor microenvironment, continues to limit the broader impact of T cell-engaging therapies in this setting.
Chief Scientific Officer
Deck Bio
Xtalks spoke with Johanna Kaufmann, PhD, Chief Scientific Officer of Deck Bio, about the company’s scientific strategy, its focus on tumor heterogeneity and resistance and why Cambridge, Massachusetts, was chosen as the launchpad for the company. The discussion explored how Cambridge’s ecosystem supports complex immuno-oncology innovation and the challenges that remain, even in one of biotech’s most established hubs.
Deck Bio is a pre-seed biotechnology company developing multi-target T cell engagers for solid tumors. It is working to address some of the challenges around T cell-engaging therapies through its multi-target T cell engager platform designed for solid tumors.
The company launched its Multi-Target T Cell Engager Platform for solid tumors in April 2026 with a focus on multi-peptide-major histocompatibility complex (multi-pMHC) targeted T cell engagers. Its lead program, DBXO-1, is advancing through preclinical development for major solid tumor indications, including non-small cell lung cancer (NSCLC) and gastroesophageal cancer.
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A Multi-Target Approach to a Heterogeneous Disease
T cell engagers are bispecific antibody-like molecules designed to bring T cells into close contact with cancer cells. One arm recognizes a cancer-associated target, while the other binds to a marker on T cells, helping cytotoxic T cells kill tumor cells.
As Kaufmann explained, the approach is already well-established in hematologic malignancies, where multiple FDA-approved therapies have demonstrated the clinical and commercial potential of the modality.
However, solid tumors present a different set of problems. “There are fewer good targets out there for solid tumors,” Kaufmann said. She pointed to intratumoral heterogeneity, resistance mechanisms and manufacturing complexity as key reasons why T cell engagers have so far been limited to more niche solid tumor applications.
Deck Bio’s platform is designed to address these issues by targeting peptide-MHC complexes, which are generated through the body’s natural immune surveillance mechanisms. Rather than relying on a single cell-surface antigen, Deck Bio’s approach is intended to recognize multiple tumor-exclusive intracellular targets displayed as peptide-MHC complexes.
According to Kaufmann, this could help increase both the number of eligible patients and the likelihood of response. By recognizing multiple peptide-MHC targets with a single drug, the company aims to capture tumors that express one, two or several relevant target proteins, creating what Kaufmann described as a “stacking effect” of target expression.
This strategy is aligned with next-generation engineering approaches in the T cell engager field that improve target selection, expand the therapeutic window and reduce toxicity. Recent solid tumor advances, including tebentafusp in metastatic uveal melanoma and tarlatamab in small-cell lung cancer, have helped validate the approach, but the field continues to face challenges around antigen density, off-tumor effects and resistance.
Target Specificity as a Safety Imperative
Specificity is central to the development strategy for Deck Bio. T cell engagers are potent because they can repeatedly recruit T cells to kill multiple cancer cells. But that same potency means even low-level target expression in healthy tissues can create safety concerns.
“You need a very clean expression profile of the targets you go after because even some low-level expression in healthy tissues can lead to unwanted toxicities,” Kaufmann said.
Deck Bio is pairing its multi-target approach with dbSCOPE, a specificity profiling platform designed to help evaluate off-target interactions. The company is also using dbTv, a proprietary stabilized binder technology that can be formatted into different therapeutic molecules, beginning with T cell engagers.
At the AACR Annual Meeting 2026, Deck Bio presented preclinical data for DBXO-1 showing multi-target engagement, deep specificity profiling against 13,849 HLA-A*02:01-presented peptides from healthy tissues, more than 1,000-fold EC50 selectivity for target versus off-target peptides and an estimated elimination half-life exceeding 7.5 days in human FcRn transgenic mice. The company said it is continuing preclinical development of DBXO-1, including additional safety and efficacy studies.
Expanding Patient Access Through HLA Strategy
Because pMHC-targeted T cell engagers are HLA-restricted, patient eligibility depends in part on the prevalence of specific HLA alleles across populations. Kaufmann said Deck Bio’s first program is directed at the most prevalent HLA allele in the US and Western geographies, while a second program is intended to expand the concept to HLA types more common among people of Asian descent.
That geographic and population-level strategy could become important as the company considers additional pipeline opportunities and potential partnerships. It also reflects the development challenge of building highly targeted therapies without limiting access to very narrow patient populations.
Why Cambridge?
Cambridge, Massachusetts, has long been one of the world’s most concentrated biotech hubs, bringing together scientific talent, venture capital, pharma partnerships and startup infrastructure within a dense life sciences ecosystem. For early-stage companies, that proximity can shape everything from hiring and fundraising to scientific strategy and translational development.
Deck Bio’s decision to launch in Cambridge was not incidental. The company was founded by Jack Silberstein, PhD, a Stanford-trained protein engineer who chose the Greater Boston area for its combination of talent, scientific density and startup infrastructure.
“The talent pool in a hub like Cambridge or Boston is just immense,” Kaufmann said.
For a company working on complex T cell engager design, that talent pool matters. Kaufmann said Deck Bio needs both deep technical expertise in areas such as protein engineering and broader R&D experience from individuals who understand how to move an early idea toward the clinic.
The Cambridge ecosystem also provides access to pharma companies, strategic venture arms, investors, peer mentors and incubator infrastructure. Deck Bio is located at LabCentral, a Cambridge-based nonprofit biotech incubator that provides shared lab space, startup support, industry and investor connections and programming for early-stage life science companies.
Massachusetts remains one of the most active life sciences markets in the US. According to MassBio’s 2025 Biopharma Funding & Pipeline Report, Massachusetts-headquartered companies raised $6.85 billion across 197 venture capital rounds in 2025, while drug candidates in the state’s pipeline increased by nearly 14% year over year.
For early-stage biotechs, Kaufmann said the value of the ecosystem often comes through informal connections as much as formal meetings. “Networking isn’t just about free food and drinks,” she said, noting that unplanned conversations can lead to insights on fundraising, scientific strategy, partnerships and hiring.
“This is obviously an attractive place for large pharma to have a presence. And the flip side for us on the small company side is that we have access to many of those pharma companies, which allows us to explore partnership opportunities. Some of these companies have strategic venture capital arms that might be potential investors for us.”
The Constraints of a Dense Biotech Hub
Even in a leading hub like Cambridge, there are trade-offs. Kaufmann pointed to cost, real estate constraints, commuting patterns and neighborhood-specific talent dynamics as challenges companies must consider when deciding where to build.
Cambridge carries reputational value, especially in and around Kendall Square, but that also makes it expensive and competitive. Companies may save money by moving farther into the Greater Boston suburbs, but that can affect recruitment depending on the type of talent they need.
“The Cambridge name counts,” Kaufmann said, but she added that finding the right space and retaining the right talent is not as simple as having a Cambridge address.
A company relying heavily on senior management and outsourced R&D, for example, may thrive in a suburban location, while a lab-intensive startup recruiting recent graduates may benefit more from proximity to Cambridge’s dense scientific community.
A Platform Bet on Solid Tumor Immunotherapy
Deck Bio’s early strategy reflects several major questions shaping the next generation of cancer immunotherapy, which include how to safely access intracellular targets, how to address heterogeneity before resistance emerges, how to expand eligibility across patient populations and how to design potent molecules that can still be manufactured at scale.
For now, the company’s immediate priority is advancing its lead asset toward development candidate nomination and then toward the clinic, where its multi-pMHC targeting approach can be tested more directly.
Most therapies for solid tumors eventually encounter resistance, Kaufmann said. Deck Bio’s goal is to get ahead of that biology through multi-targeting, specificity engineering and a platform approach designed to make T cell engagers more broadly applicable in solid tumors.
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