Xichang Bio Files for IPO: Building a Trillion-Scale Fully Human Fab Phage Display Library to Empower Diagnostics and Biopharma with Cost-Efficient Solutions

According to data from the China Commercial Industry Research Institute, China's biopharmaceutical market size reached RMB 1.868 trillion in 2022, a year-on-year increase of 8.30% compared with 2021. Forecasts indicate that the market size will grow to RMB 1.9755 trillion in 2023 and is expected to exceed RMB 2 trillion in 2024.

The prosperity and expansion of the pharmaceutical industry are inseparable from the support of upstream raw materials and equipment.Taking biological reagent raw materials as an example, according to data from Frost & Sullivan, the market size in China grew from RMB 7.2 billion in 2015 to RMB 13.6 billion in 2019, and is projected to reach RMB 24.6 billion by 2024, with a compound annual growth rate (CAGR) of 13.8% between 2019 and 2024.

Among these, antibodies represent the largest segment of China’s protein reagent market, accounting for 67.0% of the total market size in 2019. The recombinant protein market has also experienced rapid growth, with its domestic market size increasing from RMB 400 million in 2015 to RMB 900 million in 2019, at a compound annual growth rate (CAGR) of 20%. This upward trend is expected to continue in the coming years.

Despite strong demand for upstream raw materials such as antibodies, recombinant proteins, and protein chips, imported products still dominate the majority of pharmaceutical and diagnostic upstream supplies in China, leaving substantial room for domestic substitution. The localization—and even global expansion—of upstream biopharmaceutical materials and equipment holds significant value for the Chinese pharmaceutical industry in achieving cost reduction and efficiency improvement. Recognizing this market gap, Shanghai Constreambio Co., Ltd. (hereinafter referred to as “Constreambio”) has rapidly built a one-stop service platform for antibodies and recombinant proteins, positioning itself to achieve rapid advancement and overtake competitors in the emerging CXO sector.

Constreambio was established in July 2023, with its core team hailing from prestigious institutions such as Shanghai Jiao Tong University and Fudan University. The core members have known each other for over a decade and possess more than 15 years of end-to-end industry experience in biopharmaceuticals. They have mature R&D and process development capabilities across various drug modalities, including antibodies, antibody-drug conjugates (ADCs), and CAR-T therapies.

Dr. Tao Weihong, Co-founder and CEO of Constreambio, with many years of industry experience in the field of biopharmaceuticals. Previously served as the person in charge of cell line construction and CMC for multiple biological drugs, including monoclonal antibodies and fusion proteins, and developed several serum-free culture medium formulations; also led or participated in IND and BLA filings for multiple antibody or fusion protein drug projects.

Wang Peng, Chief Operating Officer, also brings many years of experience in the biopharmaceutical industry, with extensive expertise in antibody discovery and engineering. He has led or participated in multiple Investigational New Drug (IND) and Biologics License Application (BLA) submissions for antibodies and CAR-T therapies. Previously, he held long-term positions at Roche and CARsgen Therapeutics, where he spearheaded the discovery of the single-chain antibody used in CARsgen’s marketed product, zevor-cel. The Chief Technology Officer possesses extensive experience in large-molecule pharmaceutical development, molecular evaluation, and engineering optimization. He previously served as the overall project leader and CMC head for multiple monospecific and bispecific antibody projects, as well as Antibody-Drug Conjugate (ADC) programs, and has led or contributed to IND and BLA filings for several large-molecule projects.

In addition to its strong technical talent pool, Constreambio also boasts two industry veterans with extensive experience in business development and market operations. Chief Business Officer Cao Gui has over 10 years of experience in business development and marketing within the biopharmaceutical industry, having achieved cumulative sales amounting to hundreds of millions of yuan. He excels in integrating and coordinating resources across the upstream and downstream segments of the industry, as well as establishing strategic partnerships and alliances. Marketing Director Min Qiang also brings more than 10 years of sales and management experience in the fields of antibody and cell quality. He offers unique insights into manufacturing processes, particularly in providing comprehensive upstream solutions and technical consulting services.

In today’s sluggish economic climate, the formation of this entrepreneurial team—composed of individuals with extensive industry experience and complementary strengths—stems from a common pain point encountered by Dr. Tao and his partners at Constreambio during their previous research and pharmaceutical careers: “In the R&D and production of biopharmaceuticals, most instruments and reagents are sourced from overseas. These imported products are not only expensive but also have long lead times, significantly hindering the progress of pharmaceutical R&D and industrialization.”

In China’s antibody reagent market, the low market share held by domestic manufacturers has long been a persistent pain point. According to data from Dongguan Securities, imported brands dominate the industry in terms of market concentration, accounting for nearly 90% of the market share. Among them, Abcam, Merck, CST (Cell Signaling Technology), and Thermo Fisher hold market shares of 8.4%, 7.3%, 6.6%, and 5.7%, respectively. Most domestic manufacturers are small in scale, offer a limited product portfolio, and primarily compete in the mid-to-low-end segment.

Among these, the domestic recombinant protein reagent market is also predominantly occupied by foreign products. According to data from Frost & Sullivan, in 2019, the combined market share of the top five companies (CR5) in China’s recombinant protein reagent market was approximately 47%. Foreign manufacturers R&D Systems and PeproTech ranked first and second, with market shares of 20% and 16%, respectively. Domestic enterprises Sino Biological, ACROBiosystems, and Nearshore Protein held market shares of only 5%, 4%, and 2%, ranking third, fourth, and fifth, respectively.

Recognizing these industry pain points and the vast potential for domestic substitution, Constreambio was rapidly established to serve clients in biopharmaceuticals, biological reagents, and in vitro diagnostic (IVD) reagents. The company provides third-party professional technical services, antibody and antigen raw materials, and custom reagent development, with a commitment to helping the pharmaceutical industry reduce costs and enhance efficiency.

Currently, in addition to the founding team’s extensive and interdisciplinary backgrounds in scientific research and industrialization, Constreambio as a whole is also a multidisciplinary team driven by R&D and industrialization. Through the interdisciplinary integration with the biopharmaceutical industry and technological innovation, Constreambio has initially established a series of proprietary core technologies and related process development platforms.

An outstanding industrial team naturally deserves to be matched with an equally exceptional capital team. Early this year, Constreambio completed an angel financing round in the tens of millions of RMB, with most of the lead and follow-on investors being long-time friends and former research collaborators of Dr. Tao.

Dr. Tao recalled, “We knew each other inside out and had clear goals,"So we met with the investors twice, and they decided to invest.""The company also minimized many unnecessary teething problems in its early stages, enabling faster overall operations."

It is worth noting that, in the public perception, the CXO (Contract Research/Development/Manufacturing Organization) sector is typically considered capital-intensive, with high upfront costs for facilities and equipment. However, Constreambio faces no such concerns. By fully leveraging its partners’ industrial resources and the research commercialization capabilities of universities supported by national policies, the company has made virtually zero investment in facilities and equipment. Dr. Tao remarked with a smile, “Even if we were not profitable, our angel-round funding would be sufficient to sustain Constreambio’s operations for three years. But profitability is inevitable—we have already secured cumulative orders worth several million yuan.”

Driven by the combined strength of its team and capital support, Constreambio currently operates six major technical service platforms: hybridoma screening, phage display, alpaca nanobody development, transient and stable cell line construction, process development and quality analysis, and large-scale production. Its portfolio includes IVD Constreambio.^®(Xili Diagnostics), Constreambio^®(Xidi Pharma) These two major service brands can provide customers with protein raw materials and early-stage technical services for pharmaceutical R&D.

Among them, Xili Diagnostics leverages its technology platforms in protein design and genetic engineering, transient and stable expression systems, purification and quality control, as well as activity assay and screening, to provide core raw material formulation development and long-term supply for customers in the diagnostic and biological reagent sectors.

Xidi Pharma, leveraging its new drug discovery platforms (phage display platform, hybridoma screening platform, and alpaca nanobody platform), drug development platforms (druggability assessment, transient/stable/electroporation-based protein expression platforms, and upstream/downstream process development platforms), and multi-scale manufacturing capabilities (10 L, 50 L, 200 L, and 500 L), provides end-to-end support for the early-stage R&D of biopharmaceutical clients, helping them reduce costs and enhance efficiency.

Leveraging the aforementioned technology platforms and brand, Constreambio has established unique, technologically leading advantages in its one-stop service platform for antibodies and recombinant proteins.

Specifically, in the field of antibody humanization services, Constreambio can complete antibody humanization design within 24 hours. In terms of antibody engineering, Constreambio possesses mature technologies for affinity maturation, deimmunization, and aggregation reduction. For gram-scale protein antibody production, Constreambio can produce 1 g of protein in as little as 3 weeks and 10 g in as little as 6 weeks.

Notably, in the antibody engineering phase, Constreambio currently possesses fully synthetic Fab libraries and single-domain antibody libraries, and is continuously expanding the diversity and capacity of these libraries.Phage display libraries can be broadly categorized into naïve, immune, semi-synthetic, and fully synthetic libraries. Compared with naïve libraries, antibodies selected from synthetic libraries generally exhibit superior developability and higher affinity. Representative examples of synthetic libraries include the HuCAL-GOLD, HuCAL-PLATINUM, and Ylanthia libraries developed by MorphoSys AG in Germany. These libraries employ representative germline sequences as framework regions, selected based on natural germline sequence abundance and combinatorial diversity, antibody expression and stability, and phage display levels. The complementarity-determining regions (CDRs) are randomized via primers to generate a series of diverse libraries.

Phage display technology is a critical screening platform for antibody drug development, and multiple antibodies developed using this technology have already been marketed. The key to phage display technology lies in the quality of the library. Generally, a phage display antibody library must have a diversity of over one billion clones to increase the likelihood of identifying superior antibodies. Currently, Constreambio’s fully human Fab synthetic library has a diversity of 10¹⁰(billion), which can be used for the screening of the vast majority of targets. The company plans to complete the establishment of a hundred-billion-scale fully human Fab synthetic library by 2026, so as to develop high-affinity and high-specificity candidate antibodies for pharmaceutical companies and diagnostic reagent companies, thereby generating sales revenue in the tens of millions.

In addition, Constreambio has innovatively expanded into popular niche sectors such as antibody-drug conjugates (ADCs) around its core antibody raw materials. The company offers services including ADC payload monoclonal antibody preparation, customized development of CHO cell host cell proteins (HCP), and customized development of anti-drug antibodies (ADA). Furthermore, in response to dynamic market demands, Constreambio is gradually laying out a portfolio of single-product antibody raw materials with significant potential for market substitution.

Regarding the company’s future development, Dr. Tao remarked with a smile, “In the current macroeconomic environment, our short-term goal is naturally to achieve self-sustainability as soon as possible. Our longer-term vision is for Constreambio to evolve into a ‘small but beautiful’ enterprise distinguished by its phage display technology, providing high-value, cost-effective antibody raw materials to the pharmaceutical and diagnostics industries.” We look forward to Constreambio supporting domestic diagnostics and pharmaceutical companies in accelerating import substitution, delivering high-quality, affordable services and antibody raw materials to customers, and ultimately making products more accessible to patients.