OBI Pharma Announces Ten Poster Presentations at the AACR 2026 Annual Meeting for GlycOBI(R) Glycan-based Site-Specific Antibody-Drug Conjugates (ADCs): Mono and Bi-Specific (inc. Dual payload) and Obrion(TM) ADC enabling technologies

Poster Presentations featuring the latest advancements on anti-TROP2 (OBI 902) and Nectin-4 (OBI 904) ADCs, anti-TROP2/HER2 BsADC (OBI 201), anti-cMET/HER3Bs-Dual Payload ADC (OBI 221),and OBI's novel Obrion ^™ ADC enabling technologies(GlycOBI ^® and GlycOBI DUO ^®).

TAIPEI, TW / ACCESS Newswire / April 15, 2026 / OBI Pharma, Inc. (TPEx:4174.TWO) today announced its presence at AACR 2026, highlighted by ten poster presentations, showcasing the transformative potential of the GlycOBI^® platform. Conventional ADCs often face limitations due to random conjugation, resulting in heterogeneous Drug-to-Antibody Ratios (DAR), suboptimal stability, and narrow therapeutic windows. In contrast, the OBI site-specific glycan-based technology enables a highly homogeneous DAR, translating into improved PK/PD profiles, and reduced off-target toxicity, as demonstrated by OBI's lead programs, OBI-902 and OBI-904.

We are further advancing precision oncology through our next-generation bispecific (OBI-201) and bispecific, dual-payload (OBI-221) ADCs. These "biology - driven" molecules are designed to overcome tumor heterogeneity and multi-drug resistance-key challenges in current cancer treatment. By incorporating both the GlycOBI^® and GlycOBI DUO^® platforms, OBI is developing novel and differentiated therapeutics addressing the unmet medical need for patients with difficult-to-treat solid tumors. Additionally, OBI's robust ADC conjugation platform has proven to consistently deliver product quality and scalability, while enabling expansion into next-generation modalities, including degrader-antibody conjugates (DACs).

These data will be presented at the American Association of Cancer Research (AACR) Annual Meeting from April 17 to 22, 2026 in San Diego, CA. (USA).

"At OBI, we make better ADCs," said Dr. Ya-Chi Chen, Chief Scientific Officer OBI Pharma. "Our goal is to deliver therapies that not only target tumors more effectively and precisely, but also reduce side effects, giving patients potentially life-changing treatment options."

Monday, April 20, 2026 (9:00 AM - 12:00 PM)

Title: Overcoming Resistance with OBI-902: Preclinical Evaluation of a Next-Generation TROP2 ADC1

Authors: Ren-Yu Hsu, Chi-Huan Lu, Chi-Sheng Shia, Jing-Rong Huang, Hsin-Shan Wu, Lu-Tzu Chen, Jhih-Jie Yang, Tzu-Min Yen, Jyy-Shiuan Tu, Yu-Hsuan Tsao, Ya-Chi Chen. OBI Pharma, Inc, Taipei, Taiwan

Session Title: PO. ET07.01 - Quantitative Pharmacology and Translational Modeling
Location: Poster Section 17
Poster Board Number: 6
Abstract Presentation Number: 1818

Title:OBI-904, a Next-Generation Nectin-4-Targeting Exatecan ADC, Demonstrates Enhanced Cytotoxicity and Overcomes Enfortumab Vedotin Resistance2

Authors :Yuan-Liang Wang, Chi-Huan Lu, Woan-Eng Chan, Shin-Jin Lin, Ting-Yu Chang, Hong-Syuan Lin, Wei-Jhen Huang, Ya-Chi Chen. OBI Pharma, Inc, Taipei, Taiwan

Session Title: PO.ET02.02 - Antibody-Drug Conjugates and Linker Engineering 2
Location: Poster Section 13
Poster Board Number: 26
Abstract Presentation Number: 1729

Title: OBI-904, a Glycan-based Site specific Nectin-4-Targeted ADC, Demonstrates Potent and Durable Antitumor Activity with an Improved PK Profile and Overcoming EV-Resistance in Non-Clinical Studies3

Authors: Chi-Huan Lu, Ren-Yu Hsu, Jing-Jie Ciou, Tzu Min Yen, Jyy-Shiuan Tu, Yu-Hsuan Tsao, Jing-Rong Huang, Ya-Chi Chen. OBI Pharma, Inc., Taipei, Taiwan

Session Title: PO.ET07.01 - Quantitative Pharmacology and Translational Modeling
Location: Poster Section 17
Poster Board Number: 7
Abstract Presentation Number: 1819

Title: The MET/HER3 Antibody-Drug Conjugate with Dual Payload: A Dual-Target Approach to Eliminate Tumor Escape Mechanisms5

Authors: Yuan-Liang Wang, Chi-Huan Lu, Woan-Eng Chan, Ting-Yu Chang, Hong-Syuan Lin, Cheng-Yen Wei, Shin-Jin Lin, Lu-Tzu Lu, Meng-Hsin Liu, Wei-Jhen Huang, Ya-Chi Chen. OBI Pharma, Inc., Taipei, Taiwan

Session Title: PO.CL.0705 - Targeted Antigen Therapies and Immunity
Location: Poster Section 49
Poster Board Number: 17
Abstract Presentation Number: 2665

Title: Guide-effector bsADCs: Driving co-endocytosis for enhanced payload delivery6

Authors: Wei-Jhen Huang, Woan Eng Chan, Meng-Hsin Liu, Yueh Chin Wu, Ya-Chi Chen .OBI Pharma, Inc., Taipei, Taiwan

Session Title: PO.ET02.02 - Antibody-Drug Conjugates and Linker Engineering 2
Location: Poster Section 13
Poster Board Number : 27
Abstract Presentation Number: 1730

Title: Hydrophilicity-Enhanced Linker Technology Enables Site-Specific Degrader-Antibody Conjugates with Improved Stability and Enhanced Activity7

Authors: Yu-Hung Chen, Wei-Chien Tang, Chi-Dian Lu, Hung-Yi Lin, Wei-Jhen Huang, Nan-Hsuan Wang, Ya-Chi Chen, Teng-Yi Huang. OBI Pharma, Inc., Taipei, Taiwan

Session Title: PO.ET02.02 - Antibody-Drug Conjugates and Linker Engineering 2
Location: Poster Section 13
Poster Board Number: 28
Abstract Presentation Number: 1731

Title: Cell-based payload release highlights design, site, and cell-dependent ratio shifts in dual-payload ADCs8

Authors: Nan-Hsuan Wang, Wei-Han Lee, Evelyn He, Li Chuan Huang, Yu-Chao Huang, David Teng-Yi Huang, Ya-Chi Chen. OBI Pharma, Inc, Taipei, Taiwan

Session Title: PO.CH01.06 - Antibodies, Antibody-Drug Conjugates, and Nucleic Acids
Location: Poster Section 38
Poster Board Number: 5
Abstract Presentation Number: 2397

Monday, April 20, 2026 (2:00 PM - 5:00 PM)

Title:TROP2 Upregulation and Interaction with HER2 Mediate Trastuzumab Resistance4

Authors: Yuan-Liang Wang, Chi-Huan Lu, Cheng-Yen Wei, Jye-Yu Huang, Woan-Eng Chan, Lu-Tzu Chen, Ya-Chi Chen. OBI Pharma, Inc., Taipei, Taiwan

Session Title: PO.ET03.06 Drug Resistance 1: Antibodies and ADCs
Location: Poster Section 12
Poster Board Number: 18
Abstract Presentation Number: 2972

Tuesday, April 21, 2026 (9:00 AM - 12:00 PM)

Title: Glycan-based site specific ADC Achieves Sustained Tumor Control through Improved Payload Delivery and Immune Activation9

Authors: Liu Chih-Chun, Tsai Yi-Chien, Huang Jing-Rong, Lo Fei-Yun, Pei Yu, Hsu Ren-Yu, Tu Tzu-Hsuan, Chen Ya-Chi. OBI Pharma, Inc, Taipei, Taiwan

Session Title: PO.IM02.04 - Adaptive Immunity in Cancer
Location: Poster Section 6
Poster Board Number: 2
Abstract Presentation Number: 4234

Title: Advancing ADC therapeutics with next-generation site-specific glycan conjugation and dual-payload flexibility10

Authors: Wei-Chien Tang, Yu-Hung Chen, Chih-Kang Chang, Ting-Wei Liu, Hung-Yi Lin, Wei-Jhen Huang, Chi-Huan Lu, Ren-Yu Hsu, Nan-Hsuan Wang, Ya-Chi Chen,Teng-Yi Huang. OBI Pharma, Inc, Taipei, Taiwan

Session Title: PO.ET02.03 - Antibody-Drug Conjugates and Linker Engineering 3
Location: Poster Section 12
Poster Board Number: 1
Abstract Presentation Number: 4423

The e-posters will be available for browsing at the AACR virtual meeting platform beginning at 12:00 PM PT on April 17, as well as on the OBI Pharma website (www.obipharma.com) beginning on April 18.

^{1 AACR Annual Meeting 2026 Abstracts online} https://www.abstractsonline.com/pp8/#!/21436/presentation/4583

^{2 AACR Annual Meeting 2026 Abstracts online} https://www.abstractsonline.com/pp8/#!/21436/presentation/5385

^{3 AACR Annual Meeting 2026 Abstracts online} https://www.abstractsonline.com/pp8/#!/21436/presentation/4588

^{4 AACR Annual Meeting 2026 Abstracts online} https://www.abstractsonline.com/pp8/#!/21436/presentation/5030

^{5 AACR Annual Meeting 2026 Abstracts online} https://www.abstractsonline.com/pp8/#!/21436/presentation/4051

^{6 AACR Annual Meeting 2026 Abstracts online} https://www.abstractsonline.com/pp8/#!/21436/presentation/5400

^{7 AACR Annual Meeting 2026 Abstracts online} https://www.abstractsonline.com/pp8/#!/21436/presentation/5401

^{8 AACR Annual Meeting 2026 Abstracts online} https://www.abstractsonline.com/pp8/#!/21436/presentation/6474

^{9 AACR Annual Meeting 2026 Abstracts online} https://www.abstractsonline.com/pp8/#!/21436/presentation/1311

^{10 AACR Annual Meeting 2026 Abstracts online} https://www.abstractsonline.com/pp8/#!/21436/presentation/5403

About OBI Pharma

OBI Pharma is a clinical-stage global oncology company established in 2002 and headquartered in Taiwan. Together with its subsidiary OBI Pharma USA, Inc., the company is dedicated to developing innovative cancer therapeutics to provide new treatment options for patients with urgent medical needs.

OBI's research efforts center on novel antibody-drug conjugates (ADC). Through its patented next-generation conjugation technology platform, Obrion™, OBI has established diverse ADC design modalities. The platform integrates proprietary conjugation and linker technologies, including GlycOBI^®, GlycOBI DUO^®, EndoSymeOBI^®, HYPrOBI^®, and the novel irreversible cysteine-conjugation technology ThiOBI^® , to advance next-generation ADC solutions. OBI has developed a next-generation suite of ADC programs. These include monospecific ADCs such as OBI-902 (TROP2), which is under Ph1 clinical evaluation, and OBI-904 (Nectin-4); a bispecific single-payload ADC, OBI-201 (HER2 x TROP2); and a bispecific dual-payload ADC, OBI-221 (cMET x HER3). To broaden the applicability of the HYPrOBI^® linker technology, OBI has further developed the ThiOBI^® technology to enable irreversible cysteine-based conjugation. In addition to its ADC programs, OBI's assets include OBI-3424, a first-in-class AKR1C3-targeted small-molecule prodrug that selectively releases a potent DNA-alkylating agent in the presence of the aldo-keto reductase 1C3 enzyme, which is highly expressed in certain tumors. Additional information can be found at www.obipharma.com.

About OBI-902 and OBI-992

OBI-902 is a TROP2-targeted antibody-drug conjugate (ADC) that carries a potent topoisomerase I inhibitor payload to kill tumor cells with a drug-antibody ratio (DAR) of 4. TROP2 is highly expressed in a variety of solid tumors such as breast, lung, biliary, bile duct (cholangiocarcinoma), ovarian, gastric, and many other cancer types, rendering it an ideal target for cancer therapy.

OBI-902 is a novel site-specific glycan-conjugated ADC using OBI's proprietary GlycOBI^® platform, which provides improved stability and enhanced hydrophilicity. OBI-902 demonstrated remarkable antitumor efficacy across multiple tumors, including NSCLC, triple-negative breast cancer (TNBC), and gastric cancer, improved pharmacokinetic characteristics, and a favorable safety profile in various animal models. The IND of OBI-902 was cleared by the United States Food and Drug Administration (US FDA) on April 30, 2025, received Orphan Drug Designation (ODD) from the US FDA for cholangiocarcinoma on Nov. 16, 2025, and gastric cancer (GC), including gastroesophageal junction cancer (GEJC) on December 5, 2025.The Phase 1/2 Study (NCT07124117) is ongoing, with completion of the Phase 1a portion targeted for 1H 2027.

OBI-992 is a TROP2-targeted antibody-drug conjugate (ADC) that carries a potent topoisomerase I inhibitor payload with drug-to-antibody ratio of 4 (DAR 4) via a cysteine conjugated, hydrophilic and enzyme-cleavable linker. OBI-992 remains stable in circulation and delivers this cytotoxic payload to TROP2-expressing tumor cells, leading to tumor cell death while avoiding off-target toxicities.

The US FDA cleared the IND application for OBI-992 in Jan 2024 and subsequently granted Orphan Drug Designation for the treatment of gastric cancer, including GEJC in Aug 2024. The Phase 1/2 Study (NCT06480240) has reached the putative Recommended Phase 2 Dose (pRP2D) and Phase I completion is targeted for 1H 2027.

Since December 2021, OBI has been granted by Biosion, Inc. (www.biosion.com) an exclusive license to a TROP2 targeting antibody amino acid sequence in all jurisdictions except Mainland China, Hong Kong and Macau. Biosion holds exclusive rights to that antibody sequence in Mainland China, Hong Kong and Macau. OBI holds commercial rights to OBI-992 and OBI-902 in all jurisdictions except Mainland China, Hong Kong and Macau, while Biosion holds commercial rights to OBI-992 and OBI-902 in Mainland China, Hong Kong and Macau.

About OBI-904

OBI-904 is an antibody-drug conjugate (ADC) comprised of a monoclonal antibody specifically targeting Nectin-4 (Nectin cell adhesion molecule 4), linked to a potent topoisomerase I inhibitor payload with Drug-to-Antibody Ratio of 8 (DAR8) through OBI's proprietary GlycOBI^® ADC enabling technologies, powered by a dual-function enzyme, EndoSymeOBI^®, and a novel linker, HYPrOBI^®. It is a potentially first-in-class and best-in-class glycan-based ADC designed to target multiple cancer types that express Nectin-4. Antitumor activity has been shown across several animal disease models, including HNSCC, CRC, TNBC, cervical and sarcoma cancers; OBI-904 has demonstrated a favorable safety profile in a repeat dose toxicity study in monkeys, and is now in the pre-IND stage of development.

About OBI-201

OBI-201 is a TROP2 x HER2 bispecific ADC generated by OBI GlycOBI^® ADC enabling technologies conjugated with a topoisomerase I inhibitor. Notably, OBI is the first to demonstrate that HER2 and TROP2 can interact and form a protein complex on the cell surface-a groundbreaking discovery facilitated through collaboration with a specialized AI drug discovery partner. OBI-201 offers several advantages over mono-specific TROP2 or HER2 ADCs. By targeting both antigens, it broadens tumor coverage, especially in cancers with heterogeneous or low expression of either target. Dual targeting can enhance tumor selectivity, binding avidity, and internalization, improving payload delivery to cancer cells while potentially reducing toxicity to normal cells. OBI-201 may overcome resistance associated with downregulation of targets after treatment by certain monospecific ADCs.

Animal studies revealed that OBI-201 demonstrated significantly superior anti-tumor activity compared to single-target ADCs in drug-resistant breast cancer models with extremely low HER2 expression. OBI-201 was able to sustain tumor growth suppression, indicating its potential to overcome multiple drug-resistance mechanisms. OBI-201 is a next-generation bispecific ADC poised to break through the limitations of single-target ADCs, potentially offering patients a more comprehensive and durable treatment option.

About OBI-221

OBI-221 is a Bispecific-Dual Payload ADC (BsDpADC), generated by OBI GlycOBI DUO^® technologies, targeting cMET and HER3, conjugated with dual payload of MMAE and topoisomerase I inhibitor.

In clinical practice, EGFR-targeted therapies have become a key strategy for treating non-small cell lung cancer (NSCLC) and colorectal cancer (CRC) patients. However, tumors often rapidly develop resistance by upregulating cMET and HER3 that, in turn, sustain tumor growth. Moreover, high expressions of cMET and HER3 have been observed in gastric cancer, head and neck cancer, and various other solid tumors, further underscoring the unmet medical needs.

To address this challenge, OBI Pharma leverages its proprietary GlycOBI DUO^® platform and HYPrOBI^® linker to develop a novel bispecific dual-payload antibody-drug conjugate (BsDpADC)-OBI-221. This therapeutic agent simultaneously targets cMET and HER3 while delivering synergistic cytotoxic agents, effectively combating tumor resistance and heterogeneity. This breakthrough design not only addresses an unmet medical need but also represents a forward-looking strategy for next-generation ADC development.

OBI-221 holds meaningful potential to overcome resistance to existing EGFR-targeted therapies, potentially offering patients more targeted treatment options while delivering substantial clinical value.

About GlycOBI^®
OBI has developed a unique glycan-based, site-specific ADC technology (GlycOBI^®), designed in a Plug and Play format that is compatible with any antibodies, linkers, and payloads, and supports various drug-antibody ratios (DAR)(up to 16). Powered by OBI's proprietary dual-function enzymatic technology EndoSymeOBI^® and its hydrophilic linker technology HYPrOBI^®, GlycOBI^®, a core component of OBI's Obrion^™ ADC technology family, enables the generation of site-specific and homogeneous ADCs through an efficient, scalable and streamlined two-step, one-pot conjugation process under GMP conditions.
During the conjugation process, GlycOBI^® avoids disrupting the antibody structure and ensures that the resulting ADC retains biophysical characteristics comparable to the native antibody. In addition, OBI's linker technology improves payload conjugation efficiency and reduces the propensity for aggregation or degradation, further supporting a stable and well-controlled ADC manufacturing process. GlycOBI^® has overcome limitations commonly associated with traditional ADC approaches and has demonstrated improved antitumor activity and stability in various in vivo studies. Notably, the platform supports the conjugation of both cytotoxic small-molecule inhibitors and highly hydrophobic degraders, expanding its applicability to next-generation modalities such as DACs.

About GlycOBI DUO^®

GlycOBI DUO^® is a next-generation dual-payload antibody-drug conjugate (ADC) technology built on the GlycOBI^® site-specific conjugation platform and its proprietary enzymatic conjugation strategy. It enables the precise and programmable attachment of two distinct payloads to a single antibody with tunable ratios and supports high DAR ratios, including up to DAR24. By combining complementary mechanisms of action, GlycOBI DUO^® is designed to enhance antitumor efficacy, address tumor heterogeneity, and improve the overall therapeutic index, with the potential to overcome resistance mechanisms associated with conventional ADCs-representing a promising advancement in next-generation ADC development.

About ThiOBI^®

OBI has developed a novel irreversible, cysteine conjugation ADC platform (ThiOBI^®) with improved stability, which can apply to any antibodies, linkers, and payloads. OBI's proprietary ThiOBI^® platform including linker technologies (HYPrOBI^®) can generate ADCs in different biomolecular formats, including antibody fragments, nanobodies, peptides, and proteins. Furthermore, OBI's HYPrOBI^® linker technology has improved conjugation efficiency of the payload and reduced aggregation propensity and also expanded the half-life of the ADC products. ThiOBI has overcome the limitations of traditional cysteine ADCs and achieved better antitumor activity and stability in various in vivo tests.

GlycOBI^®, EndoSymeOBI^®, ThiOBI^®, HYPrOBI^®, and GlycOBI DUO^® are registered trademarks of OBI. Obrion^™ is a trademark under registration.

Forward-Looking Statements

Statements included in this press release that are not a description of historical facts are forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Such forward-looking statements include, but are not limited to, statements about future clinical trials, results and the timing of such trials and results. Such risk factors are identified and discussed from time to time in OBI Pharma's reports and presentations, including OBI Pharma's filings with the Taiwan Securities and Futures Bureau.

COMPANY CONTACT:

Jukka Muhonen
Executive Director, Business Development
OBI Pharma USA, Inc.
1.617.821.0292
jukkamuhonen@obipharma.com

SOURCE: OBI Pharma USA, Inc.

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