Why next-generation biologics need format-native antibody discovery
For decades, antibody discovery was optimized around one extraordinarily successful output: the conventional full-length IgG.
The classic four-chain antibody — two heavy chains and two light chains — remains one of the most validated molecular formats in biotech. It has produced some of the most important therapeutics in modern medicine, such as Keytruda and Rituxan for cancer treatment and Humira and Dupixent for chronic inflammation. And it continues to be the right format for many programs.
But the antibody field is no longer a one-format field.
Today’s therapeutic frontier includes bispecifics, multispecifics, ADCs, T-cell engagers, CAR architectures, encoded antibodies, targeted delivery systems, and other complex biologic modalities. In these settings, the antibody is not always the final therapeutic format by itself. Increasingly, it functions as a modular component inside a larger design.
It may serve as a targeting domain.
It may serve as a payload carrier.
It may define the recognition domain of an engineered cell therapy.
It may be genetically encoded.
It may need to be fused, conjugated, multimerized, paired, reformatted, or combined with another binding specificity.
That shift changes what antibody discovery needs to deliver.
The problem is not that conventional antibodies have failed. They have transformed medicine. The problem is that many discovery systems were built for an era in which the default output was a full-length IgG, while many of today’s modalities require antibody building blocks with different architectural constraints.
The discovery engine has not fully kept up with the medicine.
The bottleneck: discovery format versus final modality
In many antibody programs, discovery begins in one format and development ends in another.
A team may identify a promising binder as a conventional heavy-chain/light-chain antibody, then later reformat it into a bispecific, multispecific, ADC component, CAR recognition domain, encoded biologic, or delivery module. That approach can work, and the field has developed many sophisticated engineering strategies to support it.
However, it also creates a recurring bottleneck: the molecule is often discovered before the final format has been fully imposed on it.
As a result, format liabilities can appear late.
A binder that looks promising in one architecture may behave differently after reformatting. It may lose functional geometry. It may express poorly. It may aggregate. It may create purification challenges. It may introduce manufacturability concerns. It may require extensive engineering before it becomes compatible with the modality the program actually needs.
In other words, the issue is not only binding. It is also whether the binder was discovered in an architecture aligned with its eventual use.
Chain pairing is one visible example
Bispecific antibodies make this problem especially clear.
In a conventional antibody, biological function depends on precise pairing between heavy and light chains. In a bispecific or multispecific setting, multiple chains may need to be expressed together and assembled correctly. Without the correct architecture or engineering strategy, the desired molecule can become only one species among several possible pairing outcomes.
The consequences are familiar to anyone working in the field: reduced yield of the intended molecule, additional purification burden, product heterogeneity, stability concerns, and time spent managing molecular assembly rather than advancing biology.
The industry has developed many ways to address this problem downstream. Those strategies have enabled important progress and will continue to matter.
But the deeper question is strategic:
Should format compatibility always be solved after discovery?
Or should discovery systems be designed to generate antibody building blocks closer to the format the modality actually requires?
At Leveragen, our answer is clear:
The modality should help determine the discovery format from the start.
Toward format-native antibody discovery
Leveragen’s models have been built around the idea that antibody discovery should not be limited to a single default output.
Instead of discovering conventional antibodies first and asking downstream teams to convert them later, Leveragen develops in vivo platforms designed to generate different antibody architectures natively.
We call this approach format-native in vivo antibody discovery.
The premise is simple: if the final modality requires a single-domain binder, discover single-domain antibodies from the beginning. If the final modality requires bispecific compatibility, discover binders in a common light-chain context from the beginning. If the biology calls for a conventional full-length IgG, preserve that proven format and discover accordingly.
The goal is not to declare one antibody format superior to all others. Rather, the goal is to match the discovery system to the modality.
That is why Leveragen has built three complementary in vivo antibody discovery platforms: Singularity, Universality, and Infinity.
Singularity: single-domain antibodies for modular biologics
The most direct way to remove heavy-light chain pairing dependency is to remove the light chain entirely.
Leveragen’s Singularity Suite is designed for the discovery of single-domain antibodies: compact, single-chain binders that can serve as modular components across multiple biologic formats.
Single-domain antibodies are attractive because their architecture is simple. They do not require heavy-light chain pairing. Their compact size can make them well suited for multivalent and multispecific formatting, genetic fusion, payload-conjugation designs, CAR recognition domains, encoded antibody approaches, and targeted delivery applications.
For many next-generation modalities, that compact architecture is not just convenient; it can be central to the design.
A single-domain binder can be used as a module. It can be combined with other domains. It can be encoded as a single genetic unit. It can access epitopes that may be difficult for larger antibody formats to reach. It can support formats where size, geometry, and modularity are critical.
Leveragen’s Singularity platform is designed to generate these binders in vivo rather than forcing conventional antibodies into single-domain-like applications after discovery.
That distinction matters.
A binder discovered in the intended architecture has already been shaped by the constraints of that architecture. The starting point is closer to the final modality. That can reduce the need for late-stage reformatting or rescue engineering and give development teams a cleaner path from discovery to design.
Universality: common light-chain antibodies for bispecific development
Not every program needs a single-domain antibody.
Many programs still benefit from an antibody architecture closer to a conventional IgG, but they also need compatibility with bispecific development and scalable manufacturing.
This is where Leveragen’s Universality Suite comes in.
The common light-chain strategy addresses one of the central challenges in bispecific development: light-chain mispairing. In a conventional bispecific setting, two different heavy chains may each require their own light-chain partner. When these chains are expressed together, multiple assembly products can result.
A common light-chain approach reduces that complexity by placing diverse heavy-chain binders into a shared light-chain context.
This does not mean every downstream engineering challenge disappears. Heavy-chain heterodimerization, manufacturability, developability, stability, and format-specific design still matter. But by reducing light-chain combinatorial complexity, common light-chain discovery can create a more direct path toward bispecific assembly.
The key is to solve part of the format problem upstream.
Instead of discovering two antibodies and later asking whether their light chains can be made compatible, Universality is designed to discover heavy-chain diversity in a common light-chain framework from the beginning.
That makes the resulting binders more naturally aligned with bispecific development.
For teams building bispecifics, this can shift the starting point. The question becomes less about whether two independently discovered antibodies can be forced into a compatible architecture, and more about how to select the best heavy-chain binders within a format already designed for bispecific assembly.
Infinity: full-length antibodies when the proven format is right
The rise of new modalities does not diminish the importance of conventional antibodies.
In many programs, the full-length IgG remains exactly the right answer.
Some therapeutic mechanisms benefit from the pharmacokinetics, effector functions, valency, stability, and established developability profile of a conventional antibody. Many diagnostic and veterinary applications also continue to rely on full-length antibody formats. The decades of biological, regulatory, and manufacturing experience behind conventional antibodies remain highly valuable.
That is the role of Leveragen’s Infinity Suite.
Infinity is designed for discovery of conventional full-length antibodies when the biology and application call for the classic format. It preserves the value of intact heavy- and light-chain antibody discovery while supporting broad applications across therapeutics and diagnostics.
This is important to the overall Leveragen thesis.
The future is not single-domain antibodies instead of conventional antibodies.
It is not common light-chain bispecifics instead of full-length IgGs.
It is not one platform replacing every other platform.
The future is format choice.
Different modalities require different antibody architectures. A discovery engine should be able to produce the right one.
The shift: from target-first to target-plus-format discovery
Historically, antibody discovery has often been framed as a target-first process: identify the antigen, generate binders, then engineer the molecule into the therapeutic format needed later.
That model will remain useful in many cases. But as biologics become more architecturally complex, discovery needs to become more format-aware from the beginning.
For next-generation modalities, the key question is not only:
Does this antibody bind the target?
It is also:
Does this antibody work in the format the modality requires?
That second question is increasingly decisive.
A binder for a CAR recognition domain may need different properties from a binder intended to become a full-length IgG. A binder for an ADC may need different internalization behavior and conjugation compatibility. A binder for a bispecific may need pairing compatibility and functional geometry. A binder for encoded delivery may need compact genetic architecture. A binder for a multispecific may need to behave well as one domain inside a larger molecule.
These are not downstream details; they are discovery-relevant constraints.
That is why Leveragen’s platform strategy is built around matching antibody architecture to modality requirements earlier in the process.
A discovery engine for a multi-format field
The antibody field has expanded beyond a single dominant molecular output.
That expansion is a sign of progress. Biologics are becoming more programmable, more modular, and more capable of addressing complex disease biology. But the discovery infrastructure must evolve with that progress.
If the medicine becomes multi-format, discovery must become multi-format too.
Leveragen’s approach is built around three complementary outputs:
Singularity for single-domain antibodies when the modality benefits from compact, single-chain, modular binders.
Universality for common light-chain antibodies when bispecific development requires reduced light-chain pairing complexity.
Infinity for conventional full-length antibodies when the proven IgG architecture remains the right format.
Together, these platforms reflect a simple proposition:
The right antibody building block should be discovered in the right format, in vivo, from the start.
This is the gap Leveragen is built to close.
The next generation of biologics will not be built from one antibody format alone. It will require single-domain antibodies, common light-chain antibodies, conventional full-length antibodies, and other architectures matched to specific therapeutic needs.
The modality should determine the format. And the discovery engine should be able to keep up.
What this series will cover
This essay introduces the central idea: next-generation biologics need format-native antibody discovery.
In the coming posts, we will examine each part of this platform strategy in more detail:
Why single-domain antibodies are becoming increasingly important as modular biologic building blocks.
Why common light-chain discovery can change the starting point for bispecific development.
Why conventional full-length antibodies remain essential when the biology calls for the classic IgG format.
And why in vivo discovery continues to matter in an era increasingly shaped by display technologies, synthetic libraries, computational design, and AI.
The future of antibody therapeutics is not one format; it is the right format for the right modality.
