From the formal initiation of discussions to the signing of the final agreement, the entire process took only about four months. Reflecting on the business development collaboration between Biocytogen Pharmaceuticals (Beijing) Co.,Ltd. and the Nasdaq-listed company Whitehawk Therapeutics, the project's progression was significantly faster than typical for similar deals in the industry.

Dr. Yuelei Shen, Chairman and CEO of Biocytogen, noted in an interview that the successful partnership was not only due to a meeting at the American Association for Cancer Research (AACR) Annual Meeting but, more importantly, stemmed from trust built on long-term mutual interest, thorough communication, and a high degree of alignment in needs.

He added that during the process, communication between the two parties faced almost no obstacles. Whitehawk's technical and legal teams responded extremely quickly, and Biocytogen's internal team maintained the same pace. There were no back-and-forth delays; everyone was focused on getting things done swiftly.

It is understood that Biocytogen and Whitehawk Therapeutics, Inc. recently announced the signing of a global strategic collaboration agreement covering multiple bispecific antibody-drug conjugate (BsADC) research and development projects. The two companies will jointly advance a diversified pipeline of next-generation therapeutic products.

The efficient progress of this collaboration was not accidental. It was underpinned by a precise match of needs. Furthermore, this deal signifies not just the formal landing of a BD project but also reflects a shift in the trend of Chinese innovative drug out-licensing: an increasing number of overseas companies are focusing not merely on a single mature candidate molecule but on R&D platforms capable of consistently generating high-quality molecules.

The Four-Month Deal

Dr. Shen revealed that as early as the beginning of 2026, Whitehawk had already taken notice of Biocytogen and its related bispecific ADC research achievements, gaining a preliminary understanding of the company's platform capabilities.

As exchanges deepened, in March 2026, Whitehawk and Biocytogen formally signed a Confidential Disclosure Agreement (CDA) to initiate technical and commercial discussions regarding bispecific antibody collaboration.

It is understood that during the evaluation phase for BD or project collaborations, both parties need to exchange a lot of sensitive information, such as molecular structures, platform technical details, and experimental data. A CDA ensures this information is not leaked or used for purposes outside the agreement.

Signing a CDA before collaboration can be seen as a prerequisite for initiating substantive technical and commercial discussions, allowing both parties to assess collaboration potential in a secure environment. It is often considered the first formal step before a partnership.

In April 2026, at the bustling AACR Annual Meeting in San Diego, USA, posters displaying data on bispecific ADCs at Biocytogen's booth attracted the attention of passing researchers. This also served as a crucial opportunity for the first in-depth, face-to-face exchange between Biocytogen and Whitehawk.

During the AACR meeting, the two sides held systematic discussions on Biocytogen's RenLite® common light chain platform, bispecific antibody development strategy, and future collaboration models, further accelerating the partnership's progress.

Dr. Shen stated that this collaboration came at an opportune time. Whitehawk was actively seeking a platform capable of continuously producing high-quality bispecific antibodies. Biocytogen's RenLite® common light chain platform and several already clinically validated collaborative projects provided ample confidence. The high degree of alignment in collaboration philosophy, R&D approach, and project execution methods made the entire process remarkably smooth.

After several months of continuous technical evaluation, commercial discussions, and agreement negotiations, the two parties finally signed the collaboration agreement on June 30, 2026.

According to public information, Whitehawk completed a strategic restructuring in March 2025 and subsequently focused on the R&D of next-generation ADC drugs. Currently, Whitehawk has three ADC pipelines (HWK-007, HWK-016, HWK-206), with the first two already in Phase I clinical trials. As of March 31, 2026, Whitehawk held approximately $123 million in cash and equivalents, expected to fund operations until 2028.

It is understood that Whitehawk's three pipelines were all in-licensed from WuXi Biologics. In December 2024, WuXi Biologics announced agreements with Aadi Bioscience (Whitehawk's predecessor) and others to empower Aadi to develop three next-generation ADC drugs in the preclinical stage, with an upfront payment of $44 million and a total potential deal value of up to $849 million.

Under the new agreement with Biocytogen, Biocytogen will provide up to five fully human bispecific antibodies via its RenLite® platform. Whitehawk will evaluate these using its ADC linker-payload platform technology and has the option to select resulting BsADC candidate molecules for pipeline development.

Regarding the number "five," Dr. Shen disclosed that this is just the scale for the first phase of collaboration, starting with five. If the collaboration proceeds smoothly, the number may increase in the future.

Unlike Biocytogen's past collaboration models, which primarily involved licensing out PCC (Preclinical Candidate) molecules, this deal leans more towards platform-driven early-stage joint development. What Whitehawk values is not a single ready-made candidate molecule, but Biocytogen's ability to consistently generate high-quality bispecific antibodies and the proven reliability of the RenLite® platform through multiple collaborative projects.

Why Are Bispecific ADCs Gaining Favor?

This collaboration focuses on bispecific ADCs. A look at global ADC pipeline data reveals a striking figure: according to Beacon statistics from late 2025, there are over 3,800 ADC candidate drugs globally.

Behind this surge in numbers lies a high degree of target repetition, with popular targets like HER2, TROP2, and B7-H3 already crowded with numerous products under development.

Moreover, amid this boom, of the thousands of ADC molecules in development worldwide, only about 1% have currently achieved commercial success. ADC drugs are highly complex, requiring a simultaneous balance of efficacy and safety. Target selection, antibody performance, linker stability, payload toxicity—every detail is critical.

An increasing number of R&D teams are realizing that, beyond changing the payload or optimizing the linker, the antibody itself is a key factor determining the upper limit of an ADC drug's potential.

This trend is particularly evident in the field of bispecific ADCs. A bispecific design can recognize two antigens simultaneously, potentially enhancing internalization efficiency and effectively preventing resistance caused by the loss of a single target. In the cutting-edge global bispecific ADC field, China's share of projects had surged to 59% by 2025.

In Dr. Shen's view, the rising interest in bispecific ADCs stems from the industry's pursuit of durable efficacy. Single-target therapies often face issues like target loss or activation of compensatory pathways. A dual-target design can enable more comprehensive blockade from multiple angles, including compensatory signaling pathways.

Dr. Shen believes the long-term potential of bispecific ADCs may be higher than that of monospecific ADCs, precisely due to the potential for more durable efficacy. Even if a monospecific ADC shows tumor shrinkage, the extension of progression-free survival (PFS) and overall survival (OS) is often limited. Bispecific ADCs hold the promise of bringing a qualitative change.

However, compared to traditional monospecific antibodies, antibody engineering is one of the biggest challenges in bispecific development. Issues like heavy and light chain mispairing, molecular stability, and developability have long constrained R&D efficiency.

Therefore, technology platforms that can reduce molecular engineering complexity from the source during the antibody discovery stage, improve natural pairing rates, and enhance developability are attracting increasing attention.

This is precisely the core value of Biocytogen's RenLite® common light chain platform. Dr. Shen explained that the platform employs a fixed light chain design—the light chain is fixed, with all antibodies produced using the same light chain. When creating bispecifics, one only needs to focus on the heavy chains, eliminating the issue of heavy-light chain mispairing. By creating a knob-into-hole structure between the heavy chains, a very complete and stable common light chain bispecific antibody can be produced.

In fact, Biocytogen began laying the groundwork for bispecific ADCs as early as 2021, when industry focus on this direction was not high. However, the Biocytogen team found in preclinical studies that bispecific ADCs showed significantly better efficacy and safety in PDX models compared to their corresponding parental monospecific ADCs.

Dr. Shen recalled that when discussing this with the industry at the time, many were skeptical about bispecific ADCs, and even his team had some doubts about whether they were looking in the wrong direction. They decided to push forward into clinical development with partners, and now, bispecific ADCs are a widely recognized industry trend.

For bispecific ADCs, the difficulty in creating a good antibody lies in screening. Dr. Shen used a vivid analogy to explain this logic: It's like searching for the most robust sapling in a nursery. If you only planted 50 trees, you might not find a single one suitable for a pillar. But if you planted 500,000 saplings, the probability of finding a straight, sturdy, and disease-resistant sapling increases greatly.

The same applies to antibodies. They must not have glycosylation sites, deamidation sites, easily oxidized sites, should not aggregate easily, need good hydrophilicity, and for ADC drugs, they require high internalization efficiency. To meet all these criteria, a sufficiently large library is needed to screen for that 'best of the best' molecule.

This is precisely the core logic behind Biocytogen's launch of the "Thousand Mice Ten Thousand Antibodies" plan—using a scaled-up antibody library to increase the probability of finding good antibodies, thereby providing the industry with truly differentiated "weapons" in the latter half of ADC competition.

Seven Years in the Making: The "Mouse"

The reason Biocytogen could launch the Thousand Mice Ten Thousand Antibodies plan traces back to the "mouse."

In 2013, Dr. Shen decided to undertake a difficult and long-term task: developing a fully human antibody mouse.

The difficulty lay not in modifying a few thousand base pairs in mice, but over a million. It required replacing the variable regions of the mouse's antibody heavy chain genes and kappa light chain genes with the corresponding human genes.

At that time, only Regeneron and the UK's Kymab possessed fully human antibody mouse platforms globally. Regeneron spent nearly 20 years, replacing mouse antibody gene segments piece by piece, to finally construct its fully human antibody mouse.

What Dr. Shen aimed to do was not only to create the mouse but, more importantly, to explore a proprietary technological path. He emphasized the need to avoid infringing on others' patents and develop one's own methods, necessitating a different path.

One night in late 2019, past midnight, Dr. Shen and the fully human antibody mouse team were still in the lab, awaiting the results of mouse B-cell sequencing to verify whether the antibody sequences were truly human.

Those hours of waiting were the most tense moments. The entire team had been exploring this for seven years. Starting from the project's launch in 2013, this core team of seven or eight people had dedicated their efforts, but no one knew when they would succeed.

The results finally came out, confirming the antibody sequences were indeed human. The young scientist leading the project was in tears all day. Dr. Shen recalled it as tears of joy, the hardships behind it indescribable.

This sentiment was not an exaggeration. At the time, Biocytogen chose a technological path completely different from Regeneron's—chromosome engineering technology, attempting to replace over a million base pairs in one go. While Regeneron used a segment-by-segment replacement method over nearly two decades, Dr. Shen's team, with only seven or eight people, spent the initial years developing this technology platform, not even certain of eventual success.

It was this prolonged wait with an unknown endpoint that made the verification results that night particularly precious.

Subsequently, Biocytogen built the RenMab® fully human antibody mouse platform. Building on this, the company successively developed the RenLite® common light chain platform for bispecifics and bispecific ADCs, the RenNano® platform for nanobodies, and others, constructing the RenMice® fully human antibody platform family.

In 2020, Biocytogen formally launched the "Thousand Mice Ten Thousand Antibodies" plan. Targeting over 1,000 potentially druggable targets, the plan conducts scaled antibody development on the RenMice series platforms, aiming to build a fully human antibody molecule library covering a wide range of targets.

It is worth noting that the industry often attributes the competitiveness of Thousand Mice Ten Thousand Antibodies to the antibody molecules themselves, but this is not entirely accurate.

Dr. Shen explained that the true competitive barrier of Thousand Mice Ten Thousand Antibodies lies in the target humanized mice, which are core tools for efficacy evaluation. Biocytogen is already one of the world's largest suppliers of target humanized mice. If a pharmaceutical company is already using Biocytogen's mice for drug evaluation, it naturally tends to obtain corresponding antibodies within the same system—akin to buying a specific brand of phone and then choosing the same brand's charger.

The "Target Humanized Mouse Bank" is another core preclinical product for Biocytogen. The aforementioned fully human antibody mice are primarily for antibody R&D, while target humanized mice involve replacing specific drug target genes in mice with human genes for efficacy evaluation.

The establishment of the target humanized mouse bank was also hard-won.

In 2014, when Dr. Shen decided to build the target humanized mouse bank, opposition from the team was intense. At the time, the company's annual revenue was only 10-20 million RMB, but building the animal facility would require an investment of 50-60 million RMB, with monthly maintenance costs in the millions. If no one purchased the mice, the company could face a survival crisis.

Dr. Shen decided to proceed, believing otherwise the company would remain perpetually small. He envisioned that when nearly all companies in the industry engaged in antibody R&D came to collaborate and use their mouse models, Biocytogen would truly gain influence.

The subsequent story proved this decision correct. Today, Biocytogen's target humanized mice exceed 2,000 types, covering most antibody drug companies. The "Thousand Mice Ten Thousand Antibodies" plan is built precisely upon this vast customer ecosystem—when Biocytogen is already the preferred supplier of target humanized mice for global pharmaceutical companies for efficacy evaluation, providing antibodies becomes the most natural extension of demand.

Today, "Thousand Mice Ten Thousand Antibodies" has built a library of over 1 million real fully human antibody molecule sequences. It has advanced to an AI and automation-enabled version 2.0, covering various formats including monospecific antibodies, bispecific antibodies, and nanobodies, and continues to expand rapidly.

"In Fact, We Haven't Undergone Any Transformation"

Reviewing Biocytogen's 17-year development journey, outsiders often describe it as a transformation from gene editing services to model animal products, then to fully human antibody platforms and Thousand Mice Ten Thousand Antibodies. However, Dr. Shen does not see it that way.

He pointed out that the company's founding purpose was to develop antibody humanized mice, and achieving this goal relied on gene editing technology. Similarly, antibody drug R&D necessarily requires target humanized mice as evaluation tools. Therefore, from antibody humanized mice to target humanized mice, all work is based on gene editing technology, following the same core technological logic.

In Dr. Shen's view, Biocytogen's positioning has never changed: to provide foundational tool support for drug R&D, to be the most fundamental technology platform, and to supply antibody molecules and evaluation models to global pharmaceutical companies.

The ultimate vision of this positioning is to become the "Global Source of New Drugs." Dr. Shen used an example to explain this vision: Merck's PD-1 antibody Keytruda originally came from the Dutch company Organon, which was later acquired by Schering-Plough, which in turn was acquired by Merck. Tracing back, almost the entire industry knows where this molecule originated.

Dr. Shen's vision is that in the future, the initial molecules for the vast majority of antibody drugs can be traced back to Biocytogen. Perhaps one day, a drug may pass through the hands of several companies, but when the industry traces its origin, they will still find Biocytogen's involvement at its birth. This is the true meaning of the "Global Source of New Drugs" vision.

By the end of 2025, Biocytogen had cumulatively signed over 350 drug co-development, licensing, or transfer agreements, establishing collaborations with several of the world's top 10 pharmaceutical companies, with overseas revenue accounting for over 70% of the total. Through these numbers, Biocytogen may be getting closer and closer to this vision.