What SillaJen does

SillaJen Co., Ltd. (KOSDAQ: 215600) is a clinical-stage biopharmaceutical company developing engineered oncolytic immunotherapies for solid tumors. Its core technology is a vaccinia virus backbone modified to selectively infect and replicate in cancer cells — exploiting tumor-specific genetic changes to cause tumor debulking, vascular shutdown, and systemic anti-tumor immune activation — supported by proprietary SOLVE and GEEV platforms. The lead asset, Pexa-Vec (JX-594), is in a Phase 3 trial in China for hepatocellular carcinoma (via Lee's Pharmaceutical) and in a Phase 2 combination trial with Regeneron's Libtayo for renal cell carcinoma, with a CSR submitted to the U.S. FDA for the REN026 RCC study in March 2026. The pipeline extends to BAL0891, a first-in-class dual TTK/PLK1 inhibitor in Phase 1, the next-generation SJ-600 series (Wyeth strain, including SJ-650) engineered for systemic IV delivery with complement-evasion proteins, and the JX-900 series led by JX-970 in preclinical development.

The company is headquartered in Seoul with a research center in Yongin (Gwanggyo) and a wholly-owned U.S. subsidiary, SillaJen Biotherapeutics, in San Francisco handling clinical operations, regulatory affairs, R&D, manufacturing, and alliance management. With 51–100 employees and no commercial product, SillaJen operates a licensing- and partnership-led business model: revenue is generated through milestone and collaboration payments from a small set of partners rather than product sales. 2021 revenue was KRW 254 million (a steep decline from KRW 9,068 million in 2019), but the company reported KRW 20.35 billion of operating profit and KRW 16 billion of net profit that year, reflecting non-operating items rather than commercial scaling. Co-CEOs Han Sang-gyu and Park Sang-geun currently lead the company, which faces KOSDAQ delisting-rule pressure that has driven inbound interest — including non-binding 2026 discussions with OSR Holdings / Vaximm AG over a Pexa-Vec license and a potential ~16% equity stake.

Name

SillaJen

Legal name

SillaJen Co., Ltd.

Website

https://sillajen.com

Company type

Public

Founded year

2016

Operating status

Operating

Headcount range

51–100 employees

Short description

SillaJen is a clinical-stage South Korean biopharmaceutical company (KOSDAQ: 215600) developing engineered oncolytic immunotherapies — including lead asset Pexa-Vec (JX-594) — for solid tumors, generating revenue through licensing and partnership deals with pharmaceutical companies rather than product sales.

Ownership category

akta.pro rank

Product category

Oncolytic Immunotherapy

NAICS

Research and Development in Biotechnology (except Nanobiotechnology) (541714), Biological Product (except Diagnostic) Manufacturing (325414)

SIC

Biological Products, (No Disgnostic Substances) (2836), Pharmaceutical Preparations (2834)

akta.pro primary industry

Therapeutic Vaccines (cancer, chronic infection immunotherapy) (HLAAAEAB)

akta.pro secondary industries

Oncology Gene Therapies (incl. oncolytic vectors & gene-modified approaches) (HLAAACAF), Vaccine Technology Platforms (mRNA, viral vector, protein subunit, inactivated/live-attenuated, VLP, DNA) (HLAAAEAD)

Keywords

• Oncolytic immunotherapy
• Cancer therapeutics
• Biopharmaceutical development
• Oncolytic virus platform
• Immuno-oncology drugs

Headquarters

HQ city

San Francisco

HQ country

United States

HQ region

North America

Offices3 records

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Personnel, Technology or R&D, Operations

Revenue model

1. Licensing and Partnership Revenue: SillaJen generates revenue through licensing agreements and partnerships with pharmaceutical companies for its clinical-stage oncolytic immunotherapy candidates including Pexa-Vec, BAL0891, and the SJ-600 series.
2. Revenue Growth Post-Acquisition: The company achieved significant revenue growth following acquisitions as part of defensive M&A strategy to meet KOSDAQ listing requirements.

Go-to-market motion1 record

Distribution channels1 record

Marketing channels4 records

Core offering

SillaJen is a clinical-stage biopharmaceutical company developing engineered oncolytic immunotherapies that selectively infect, replicate in, and destroy cancer cells while stimulating anti-tumor immune response. Core assets include Pexa-Vec (JX-594) in Phase 3 (PHOCUS) for liver cancer and Phase 2 for renal cell carcinoma, BAL0891 (a first-in-class dual TTK/PLK1 inhibitor) in Phase 1, and the SJ-600 series of next-generation oncolytic vaccinia viruses engineered for systemic intravenous delivery with complement evasion capability. The company operates through licensing and co-development partnerships with pharmaceutical companies rather than direct product sales.

Product overview

SillaJen is a South Korean biopharmaceutical company developing a portfolio of oncolytic immunotherapies for cancer treatment. The core product is Pexa-Vec (JX-594), a clinical-stage oncolytic virus engineered to selectively infect and replicate in cancer cells. The pipeline includes BAL0891, a dual TTK/PLK inhibitor for solid tumors in Phase 1 trials; the SJ-600 series (Wyeth Strain Backbone), a next-generation platform for improved intravenous delivery of oncolytic viruses including SJ-650; and the JX-900 series (including JX-970), representing next-generation candidates. The company operates through its Seoul headquarters, Gwanggyo research center, and San Francisco subsidiary SillaJen Biotherapeutics, which handles clinical operations, regulatory affairs, R&D, manufacturing, and alliance management for clinical trials.

Differentiator

Problem solved

Functional benefit

Products and services

• Pexa-Vec (JX-594) An engineered oncolytic immunotherapy designed to selectively infect and replicate in cancer cells, causing vascular shutdown in tumor blood vessels and stimulating immune response against cancer cells. Licensed to partners such as Regeneron (for combination with Libtayo in RCC) and Lee's Pharmaceutical (for liver cancer in China).
• BAL0891 A dual TTK/PLK inhibitor targeting two key phosphorylating enzymes involved in mitotic checkpoint; induces mitotic override and mitotic block to disrupt cancer cell cycle and trigger apoptosis. The only molecule in development simultaneously inhibiting both TTK and PLK1.
• SJ-600 Series Next-generation platform of oncolytic vaccinia viruses engineered for systemic (intravenous) delivery, expressing proteins on the viral envelope that inhibit antiviral substances (including complement activation) to improve ability to reach tumors and enable repeat dosing.
• SJ-650 An oncolytic vaccinia virus engineered for systemic (intravenous) delivery, expressing a protein on the viral envelope that inhibits complement activation to improve tumor targeting and enable repeat dosing.
• JX-970 (JX-900 Series) Next-generation oncolytic virus pipeline candidate (JX-900 series) that demonstrated tumor debulking effect and selective preference for tumor tissues in preclinical studies.

Quantifiable outcome

• Significant revenue growth following acquisitions

Named customers1 record

Segments1 record

Ideal customer profiles2 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature6 records

Partnerships

Three partnerships are on record, tiered potential and core.

• OSR Holdings / Vaximm AGpotentialStrategic or Co-development Partner · 16 March 2026Ongoing but non-binding discussions regarding potential licensing arrangement for Pexa-Vec (clinical-stage oncolytic immunotherapy for renal cell carcinoma) and preliminary discussions about acquiring approximately 16% of SillaJen's outstanding common shares. No agreement on deal structure, terms, or financing has been reached.
• RegeneroncoreStrategic or Co-development PartnerClinical trial collaboration for Pexa-Vec in combination with Regeneron's Libtayo (cemiplimab-rwlc) for renal cell carcinoma treatment. First patient enrolled in Part 2 of the renal cell carcinoma trial evaluating the combination therapy.
• Lee's PharmaceuticalcoreStrategic or Co-development PartnerPartnership for PHOCUS trial - Phase 3 clinical trial for Pexa-Vec in liver cancer in China. Lee's Pharmaceutical is responsible for clinical development and commercialization in China.

Scale indicators6 records

Recent moves6 records

Expansion highlights5 records

Direct peers

• Replimune: Clinical-stage biotech developing engineered oncolytic viruses (RP1, RP2, RP3) for solid tumors. Most direct comparable to SillaJen in oncolytic immunotherapy modality, clinical stage, and pipeline breadth.
• Transgene: French clinical-stage biotech developing oncolytic viruses (TG6002, TG4050) and listed as a SillaJen partnership contact. Comparable virus-based immunotherapy platform and clinical-stage strategy.
• Oncolytics Biotech: Develops pelareorep, a systemically delivered oncolytic virus for multiple solid tumor indications. Comparable clinical-stage oncolytic virus modality, though focused on a different virus class.
• Genelux Corporation: Clinical-stage developer of proprietary oncolytic virus platforms (Olvi-Vec and others) for cancer immunotherapy. Directly comparable in modality, clinical-stage positioning, and focus on next-generation viral delivery.

Broad incumbents

• Merck & Co. Leading IO incumbent with Keytruda (pembrolizumab) and extensive combination trials in oncology. Comparable as the dominant combination-IO partner for next-generation oncolytic virus developers.
• Bristol-Myers Squibb: Major oncology incumbent with leading checkpoint inhibitor franchises (Opdivo, Yervoy) frequently evaluated in combination with oncolytic viruses. Sets the competitive standard for combination-IO treatment paradigms.
• Amgen: Approved the first oncolytic immunotherapy (Imlygic/T-VEC) and is a major oncology player. Comparable as the established benchmark for oncolytic virus commercialization and combination-IO strategies.

Emerging players

• Lokon Pharma: Emerging biotech developing oncolytic adenoviruses engineered for tumor-selective replication and immune stimulation. Comparable smaller-scale peer in engineered oncolytic virus immunotherapy.
• Theriva Biologics: Clinical-stage developer of VCN-01 and other oncolytic adenoviruses for solid tumors. Emerging comparable in the oncolytic virus space with a similar combinatorial IO strategy.

Others

• Regeneron Pharmaceuticals: Direct partner of SillaJen on the Pexa-Vec + Libtayo RCC combination trial. Relevant as the incumbent checkpoint inhibitor partner validating SillaJen's combination strategy and a potential acquirer/co-developer.

Market position

Strengths5 records

Weaknesses4 records

Competitive moat2 records

Key risks7 records

Key highlights7 records

Customer concentration

Compliance1 record

Revenue estimate

Valuation estimate

Number of profiles

Profiles7 records

Subsidiaries1 record

Funding overview

Funding rounds1 record

Investors1 record

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A1 record

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about SillaJen