A New Breakthrough in ADC Therapeutics? Orum Therapeutics’ Next-Generation Platform Technology

The ADC (Antibody-Drug Conjugate) therapeutic market is heating up. As of November 26, 2025, the global ADC market size reaches approximately $12 billion, growing rapidly at a compound annual growth rate of 13.2%. In this context, the domestic biotech company Orum Therapeutics, headquartered in Seoul, is making ambitious strides to overcome the limitations of existing ADC technologies. Particularly intriguing is their pursuit of fundamental technological innovation rather than mere ‘me-too’ development, as evidenced by the differentiated approaches in their ongoing development of ORM-1153 and ORM-1023.

According to reports, Orum Therapeutics has established a proprietary platform to address the core limitations of existing ADC technologies. Current market leaders like Roche’s Kadcyla and Pfizer’s Besponsa face issues such as difficulty in controlling the drug-to-antibody ratio (DAR), linker stability problems, and most notably, side effects due to lack of tumor specificity. Orum’s efforts seem to be fundamentally improving these issues.

What personally stands out is that Orum Therapeutics is not merely refining existing ADC structures but has developed an entirely new conjugation method and payload delivery system. Their technical approach utilizes site-specific conjugation technology instead of the traditional non-specific conjugation methods, setting them apart from current market leaders like Seattle Genetics.

Market data shows that there are only about 15 approved ADC therapeutics worldwide, but over 500 are in clinical trials. Only a few of these will likely succeed in the market, so Orum Therapeutics will need clear differentiation points to survive this fierce competition. The development status of ORM-1153 and ORM-1023, targeting different indications, suggests a strategic approach to portfolio diversification.

Competitive Landscape and Technological Challenges in the Global ADC Market

Currently, Roche leads the global ADC market with about a 35% market share, while Daiichi Sankyo is rapidly growing with Enhertu, capturing around 25% of the market. Daiichi Sankyo has emerged as a game-changer in the ADC market, with an annual sales growth rate exceeding 150% since the launch of Enhertu in 2019. Their success factors include a significantly improved therapeutic index and expanded indications compared to existing ADCs.

However, existing ADC technologies still face many challenges. The most significant issue is the narrow therapeutic window, meaning the gap between the effective dose and the toxic dose is very small. Clinical data shows that current ADCs have a severe side effect rate of grade 3 or higher at 30-50%. Resistance development is also a major problem, as most ADCs show good initial response rates but experience resistance within 6-12 months, leading to a rapid decline in efficacy.

While specific data on how Orum Therapeutics plans to overcome these existing limitations is still limited, their emphasis on a ‘next-generation ADC platform’ suggests they are attempting a paradigm shift rather than mere improvements. Particularly, ORM-1153 is targeting HER2-positive solid tumors, a field with strong competitors like trastuzumab deruxtecan (Enhertu) and trastuzumab emtansine (Kadcyla). Achieving differentiation in this context will require a highly innovative approach.

Looking at the ADC development status of domestic biotechs, companies like Apta Bio and LegoChem Biosciences are also developing their proprietary ADC technologies. LegoChem, in particular, has signed technology transfer agreements with several global pharmaceutical companies through its ConjuAll platform, announcing cumulative technology transfer fees exceeding $1 billion as of 2024. These success stories indicate that domestic biotechs can indeed achieve global competitiveness.

Clinical Strategy and Market Entry Potential of ORM-1153 and ORM-1023

Examining the development status of Orum Therapeutics’ two main pipelines, ORM-1153 and ORM-1023, they seem to be taking different strategic approaches. According to reports, both products are currently in the preclinical stage, preparing to enter Phase 1 clinical trials. In ADC development, determining the optimal dose in Phase 1 is a critical step, given the complex toxicity profiles of ADCs compared to traditional chemotherapies or targeted therapies. Early clinical safety data will significantly influence the success of future development.

One of the most notable trends in ADC development is the creation of ‘next-generation payloads.’ To overcome the limitations of toxins like maytansinoids or calicheamicins, new payloads with novel mechanisms of action are emerging. For example, Daiichi Sankyo’s DXd (deruxtecan) used in Enhertu is over ten times more potent in cytotoxicity than existing payloads and can eliminate surrounding cancer cells through the bystander effect.

While the specific payload used by Orum Therapeutics has not been disclosed, their emphasis on ‘overcoming limitations’ suggests they may be attempting a new approach. In the ADC industry, there is active development of ‘non-cytotoxic ADCs’ using immunomodulators or epigenetic regulators as payloads, which could fundamentally solve the toxicity issues of existing ADCs.

From a market entry perspective, the ADC field is an area with very high patent barriers. Core patents held by Seattle Genetics (now Seagen, acquired by Pfizer) are valid until 2030, and Daiichi Sankyo’s DXd-related patents are extensively protected, making it challenging for new entrants to develop bypass technologies. However, this also means that companies with proprietary technology platforms have significant entry barriers. If Orum Therapeutics truly possesses differentiated technology, it could be a substantial competitive advantage.

From an investment perspective, the ADC field is currently attracting significant interest from venture capital and pharmaceutical companies. As of 2024, ADC-related investment has increased by over 40% year-on-year, with a surge in investments particularly in the Asia region. Domestically, several ADC development companies, including Orum Therapeutics, have successfully secured large-scale investments, indicating that global investors are starting to recognize the technological capabilities of Asian biotechs. However, given the high-risk nature of ADC development, a cautious approach is necessary until actual clinical data is available.

Ultimately, the success of Orum Therapeutics will depend on whether they truly possess an innovative platform capable of overcoming the limitations of existing ADC technologies. If they are merely improving existing technologies, it will be difficult to survive in the already saturated ADC market. However, if they indeed have game-changing technology, they could create significant market value. It will be interesting to see how their clinical data and technological differentiation points materialize. There is considerable anticipation for the achievements domestic biotechs can attain in the global ADC market.

This article was written by adding personal opinions and analysis after reading the Orum Therapeutics, “Overcoming ADC Limitations”… Accelerating Development of ‘ORM-1153·1023’ article.

Disclaimer: This blog is not a news outlet, and the content written reflects the author’s personal views. The responsibility for investment decisions lies with the investor, and no responsibility is taken for investment losses based on the content of this article.