Seo Jung-jin: Making Biologic Medicines More Accessible

When Seo Jung-jin entered the biotechnology industry, he had no formal medical or pharmaceutical training and limited experience in the science behind modern medicines. What he did have was a business background, a willingness to learn, and a conviction that South Korea could compete in a global industry dominated by established pharmaceutical companies.

Through Celltrion, the company he founded in 2002, Seo helped turn that conviction into a major biopharmaceutical business built around biosimilars, complex manufacturing, and global commercialization. His story illustrates how innovation can come not only from discovering a new drug, but also from finding a better way to develop, manufacture, and distribute medicines that already exist.

Table of Contents

Key Takeaways

Seo Jung-jin founded Celltrion to compete in the global biopharmaceutical industry by developing and commercializing biosimilars of established biologic medicines.
Celltrion’s Remsima, a biosimilar of infliximab, helped demonstrate that a South Korean biotechnology company could compete in major international pharmaceutical markets.
Seo’s business strategy combined self-education, scientific expertise, large-scale manufacturing, and global commercialization to build a competitive biopharmaceutical platform.
Celltrion is expanding beyond biosimilars into novel therapies, differentiated drug formulations, and additional manufacturing capabilities to support its long-term growth.
Seo’s journey shows that sustainable innovation requires more than an initial breakthrough; it also depends on regulatory compliance, operational execution, transparent governance, and continued investment.

Changing the Economics of Biologic Medicines

Some medicines are relatively simple chemical compounds. Others are biologics: complex medicines produced using living cells or biological systems. Biologics have transformed treatment for many conditions, including autoimmune diseases and cancer, but their development and manufacturing can be expensive.

When the patents on a biologic expire, another company may develop a biosimilar. A biosimilar is highly similar to an already approved reference medicine, with no clinically meaningful differences in safety, purity, and potency. It is not simply a conventional generic drug because biological medicines are more complex to reproduce and require specialized analytical, manufacturing, and regulatory work.

Seo Jung-jin recognized an opportunity in this distinction.

Rather than attempting to discover an entirely new medicine from the outset, Celltrion could focus on developing biosimilars of established biologic treatments and manufacturing them at a scale that supported international competition.

The potential benefits extend beyond the company. Additional suppliers can create more competition, potentially lower treatment costs, and give healthcare systems more options when purchasing medicines.

The business model also requires substantial investment. Biosimilars need sophisticated production facilities, extensive testing, regulatory approvals, and reliable distribution. Commercial success depends on earning the confidence of physicians, patients, regulators, and healthcare purchasers.

Seo’s central innovation was to recognize that these challenges could become the foundation of a competitive business rather than reasons to avoid the industry.

From an Uncertain Career to a Biotech Opportunity

Born in Cheongju, South Korea, in 1957, Seo studied industrial engineering at Konkuk University. Accounts of his early years describe him working as a taxi driver to support himself while pursuing his education.

His professional career began at Samsung Electro-Mechanics before he moved into consulting and a strategic role at Daewoo Motors.

The Asian financial crisis of the late 1990s changed his trajectory. Daewoo’s collapse left Seo without a stable corporate career and forced him to reconsider what he would do next.

For someone with an engineering and business background but no formal training in medicine, entering biotechnology was a substantial departure.

Yet the experience also gave Seo a different perspective on industrial opportunity. He understood corporate strategy, operations, and manufacturing, and he had seen how quickly an established business could be disrupted by economic forces.

He began examining opportunities in biopharmaceutical manufacturing, where scientific complexity created barriers to entry but also left room for ambitious new competitors.

In 1999, Seo and former colleagues established Nexol, an early predecessor to Celltrion. Celltrion itself was formally established in February 2002.

The early business operated with limited capital and had to build credibility in an industry where expertise, facilities, and regulatory compliance mattered enormously. It was a long way from the established automotive and electronics companies Seo had previously encountered.

His response was to learn the industry, recruit technical expertise, develop partnerships, and commit to building the infrastructure required to compete internationally.

Building a Manufacturing Foundation Before Global Recognition

Celltrion’s early strategy was not based solely on developing a promising molecule. It also required the company to build the physical and operational capacity to produce biologic medicines consistently.

That meant investing in specialized facilities, establishing quality-control systems, and meeting demanding manufacturing standards.

Celltrion completed its first manufacturing plant in 2005. The facility subsequently received U.S. Food and Drug Administration current Good Manufacturing Practice approval in 2007, while the company completed its initial public offering on South Korea’s KOSDAQ market in 2008.

A second plant followed in 2011, expanding the company’s manufacturing base.

These milestones were important because biopharmaceutical manufacturing cannot be scaled in the same way as an ordinary consumer product. Living-cell processes require close control, validated production methods, contamination prevention, and consistent quality across batches.

A company may have a promising drug candidate, but without dependable manufacturing, it cannot reliably serve international markets.

Celltrion’s investment in production capacity therefore became part of its innovation strategy. The company was building not just a product pipeline but a platform for developing and supplying complex medicines.

This approach also helped create a foundation for future products. Once manufacturing expertise, quality systems, and regulatory capabilities are established, they can support additional medicines and reduce the need to build every capability from scratch.

Remsima: The Breakthrough That Established Celltrion

Celltrion’s defining early achievement was Remsima, a biosimilar of infliximab, originally marketed as Remicade.

Infliximab is used to treat several inflammatory and autoimmune conditions, including rheumatoid arthritis and inflammatory bowel disease.

Developing a biosimilar to such a medicine required Celltrion to demonstrate that its product was highly similar to the reference biologic and could meet the necessary regulatory standards.

Remsima received approval in South Korea in 2012 and authorization in Europe in 2013. The U.S. FDA approved infliximab biosimilar Inflectra in April 2016, with Pfizer involved in its U.S. commercialization.

Celltrion describes Remsima as the world’s first monoclonal antibody biosimilar. The product helped establish the company as an early international competitor in a field that had previously been dominated by large pharmaceutical businesses.

Its importance went beyond a single medicine.

Remsima demonstrated that a South Korean company could develop a complex biologic biosimilar, satisfy major regulators, and compete in established pharmaceutical markets.

It also created a commercial foundation for Celltrion’s broader portfolio. Experience gained through the development and launch of Remsima could inform subsequent biosimilars, manufacturing investments, and relationships with healthcare purchasers.

For Seo, the achievement validated the business premise that innovation in biotechnology could involve making established therapies more accessible through scientific equivalence, production expertise, and competition.

Turning One Breakthrough Into a Broader Portfolio

Celltrion did not stop with Remsima.

The company expanded into additional biosimilars targeting conditions ranging from autoimmune diseases to cancer. Its portfolio has included Truxima, a rituximab biosimilar; Herzuma, a trastuzumab biosimilar; and Yuflyma, an adalimumab biosimilar.

These medicines illustrate the breadth of the opportunity. Biosimilars can address different disease areas, reference different biologic medicines, and compete in markets with distinct clinical, commercial, and regulatory requirements.

Celltrion also developed a subcutaneous formulation of infliximab. The product, marketed as Remsima SC in Europe and Zymfentra in the United States, represents a different type of innovation: modifying how an established therapy is delivered rather than simply reproducing its original formulation.

Zymfentra received U.S. FDA approval in 2023 through the regulatory pathway for a new drug. This milestone illustrates how a biosimilar-focused company can pursue product differentiation alongside its core business.

The broader strategy is important for the economics of pharmaceutical innovation.

A portfolio spreads development risk across multiple products, provides more opportunities to use manufacturing infrastructure, and can create recurring revenue to support future research. It also requires ongoing investment, as every candidate must satisfy the relevant scientific and regulatory requirements.

Celltrion’s evolution therefore demonstrates how an initial breakthrough can become the starting point for a wider innovation system.

COVID-19 and the Limits of Speed

The COVID-19 pandemic created an urgent demand for treatments and exposed the importance of having established biopharmaceutical research and manufacturing capabilities.

Celltrion developed Regkirona, an antibody treatment targeting SARS-CoV-2. The medicine received authorization in South Korea and conditional marketing authorization in the European Union in 2021.

Regkirona was designed to help treat COVID-19 in selected patients, particularly those at risk of progressing to severe disease. However, the clinical usefulness of antibody treatments depends on factors including the virus variant, the patient’s risk profile, and the timing of treatment.

As the virus evolved, some antibody therapies lost effectiveness against newer variants. This highlighted a fundamental limitation of targeted biological treatments: speed matters, but so does the ability to respond to a changing pathogen.

Celltrion’s pandemic work nevertheless demonstrated that its established research and manufacturing platform could be directed toward an urgent public-health need.

The wider lesson is that biotechnology innovation requires both preparedness and adaptability. Facilities, technical expertise, and regulatory experience can accelerate a response, but they cannot eliminate scientific uncertainty.

The Next Stage: Beyond Biosimilars

Celltrion’s current strategy aims to expand its biosimilar business while developing more differentiated medicines.

In March 2026, the company said it planned to grow its biosimilar portfolio to 41 products by 2038. Its pipeline includes candidates targeting autoimmune diseases and cancer, while its broader research programs include antibody-drug conjugates and multispecific antibodies.

Antibody-drug conjugates combine an antibody that recognizes a biological target with a linked therapeutic payload. Multispecific antibodies are designed to bind more than one target. Both approaches can be technically demanding, and their clinical value must be established through development and testing.

Celltrion has also pursued obesity and metabolic-disease research, while expanding its manufacturing infrastructure and exploring contract manufacturing opportunities.

This is a strategic transition. Biosimilars can provide a commercial base built around established medicines, while novel therapeutics offer opportunities for differentiation but carry greater scientific and development risk.

The company’s ability to balance these priorities will be central to its future. Research spending must generate a credible pipeline, manufacturing expansion must match demand, and new medicines must demonstrate advantages that justify their development costs.

Seo’s longer-term ambition is therefore not simply to increase the number of biosimilars Celltrion sells. It is to build a broader biopharmaceutical business with the capabilities to develop, manufacture, and commercialize multiple classes of medicine.

A More Integrated Global Business

Developing a medicine is only part of the challenge. Companies must also secure market access, establish distribution, negotiate with healthcare purchasers, and maintain reliable supply.

Celltrion has increasingly pursued an integrated model spanning research and development, manufacturing, and direct sales in major markets.

The merger of Celltrion and Celltrion Healthcare was completed in December 2023, bringing key parts of the group’s business structure together. The strategy was intended to improve coordination between product development, production, and commercialization.

In 2026, Celltrion also announced major manufacturing expansion plans in South Korea and the United States. The company said its new facilities and expansion projects were intended to support growing demand, improve cost competitiveness, and strengthen supply-chain resilience.

This matters in a market where production scale, supply reliability, and access to major healthcare systems can influence commercial performance.

A more integrated structure can give the company greater control over its products and customer relationships. But it also requires substantial capital, operational discipline, and the ability to manage a complex international business.

The lesson is that pharmaceutical innovation does not end when regulators approve a medicine. To reach patients at scale, the company must build the commercial and operational systems around it.

Growth, Governance, and the Cost of Ambition

Celltrion’s expansion has brought recognition as well as scrutiny.

Seo received the 2021 EY World Entrepreneur of the Year award, reflecting his role in building a South Korean biotechnology company with an international presence.

However, the group’s corporate history also includes governance issues that deserve attention. In December 2024, South Korea’s Fair Trade Commission fined Celltrion 435 million won over transactions that it concluded had provided unfair benefits to affiliates, including favorable terms involving inventory-storage fees and trademark rights. The regulator did not refer Seo to prosecutors in connection with the case.

The episode highlights the importance of transparent related-party transactions, particularly in business groups where ownership and commercial relationships overlap.

Family succession has also drawn public attention as Seo’s sons have held senior roles within the group. Such appointments can raise questions about the balance between family ownership, professional management, and independent oversight.

These issues do not erase Celltrion’s scientific or commercial achievements, but they form part of a fair assessment of its leadership and future development.

For a company operating in a highly regulated industry, governance is not separate from innovation. Trust among regulators, patients, investors, and business partners is an essential part of sustaining long-term growth.

What Business Leaders Can Learn From Seo Jung-jin

Seo’s journey offers several lessons for entrepreneurs building businesses in technically complex industries.

First, look for opportunities where established industries have overlooked a new business model. Biosimilars offered a way to compete in biopharmaceuticals without relying exclusively on discovering entirely new medicines.

Second, learn enough to recognize expertise, then build a team capable of delivering it. Seo’s business background did not replace scientific knowledge. Celltrion’s progress depended on technical specialists, regulatory capabilities, manufacturing expertise, and partnerships.

Third, invest in the infrastructure required to scale. Manufacturing facilities, quality systems, and distribution networks may be expensive, but they can become competitive advantages when they support multiple products.

Fourth, turn an initial breakthrough into a repeatable platform. Remsima was important not only as a product but also as proof that Celltrion could develop and commercialize complex biosimilars. The broader portfolio built on that foundation.

Finally, treat governance and credibility as part of the business model. Long-term success in healthcare requires more than commercial growth. Companies must demonstrate product quality, regulatory compliance, responsible management, and reliable supply.

Seo’s career illustrates the power of combining ambition with execution. It also shows why sustained innovation depends on more than an entrepreneurial origin story: the systems built after the initial breakthrough matter just as much.

Conclusion

Seo Jung-jin helped establish Celltrion as a global biopharmaceutical competitor by pursuing a different route into an industry defined by scientific complexity and high barriers to entry.

The company’s work on Remsima showed that a South Korean business could bring a monoclonal antibody biosimilar to major international markets. Its subsequent portfolio, manufacturing investments, and research programs have expanded that original ambition.

Celltrion’s future will depend on whether it can keep growing its biosimilar business while developing differentiated medicines, controlling costs, and maintaining strong governance.

Seo’s innovation story is ultimately about making a complex industry more accessible through a combination of scientific capability, industrial scale, and commercial strategy. The breakthrough was not a single invention, but a business model designed to make advanced medicines available to more patients.

FAQs

Who is Seo Jung-jin?

Seo Jung-jin is a South Korean entrepreneur and the founder and chairman of Celltrion Group. He helped build the company into a global biopharmaceutical business specializing in biosimilars and expanding into novel drug development.

What is Celltrion best known for?

Celltrion is known for developing and commercializing biosimilars, including Remsima, a biosimilar of infliximab. The company has expanded into treatments for autoimmune diseases and cancer, as well as differentiated formulations and novel therapeutic research.

What makes biosimilars different from generic drugs?

Generic drugs generally reproduce relatively simple chemical medicines, while biosimilars are highly similar versions of complex biological medicines made using living systems. Biosimilars require specialized analytical and regulatory evidence to establish that they have no clinically meaningful differences from their reference products.

How did Seo Jung-jin build Celltrion without a medical background?

Seo brought business and industrial experience rather than formal medical training. He pursued the opportunity by learning about the industry, working with technical experts, investing in manufacturing infrastructure, and building the capabilities needed to develop and commercialize biopharmaceutical products.

What is Celltrion focusing on next?

Celltrion aims to expand its biosimilar portfolio while developing novel therapies, including antibody-drug conjugates and multispecific antibodies. Its plans also emphasize manufacturing capacity, global commercialization, and stronger integration across research, production, and sales.

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