Abpro and Celltrion reveal promising preclinical results for ABP-102/CT-P72 at AACR 2025

Abpro Holdings, Inc. and Celltrion Inc. jointly presented new preclinical findings for their investigational HER2 x CD3 bispecific T-cell engager, ABP-102/CT-P72, during the American Association for Cancer Research (AACR) Annual Meeting 2025. The data revealed a strong therapeutic potential, highlighting the candidate’s ability to selectively target HER2-overexpressing tumors while reducing on-target, off-tumor toxicity — a limitation that has historically constrained the development of earlier HER2-targeted therapies.

This announcement from Woburn, Massachusetts-based Abpro Holdings, listed on Nasdaq as Abpro Holdings Inc., and South Korea’s Celltrion Inc., marks an important milestone. Their collaboration aims to advance next-generation antibody treatments for cancers with high HER2 expression, a condition accounting for up to 30 percent of cases in breast, gastric, pancreatic, and colorectal cancers.

What Makes ABP-102/CT-P72 a Potential Best-in-Class Candidate?

According to the preclinical data unveiled at the AACR 2025, ABP-102/CT-P72 demonstrated highly selective tumor-killing capabilities. In breast and gastric cancer models characterized by high HER2 expression, the drug achieved potent cytotoxic effects while showing significantly reduced activity against HER2-low cells. This level of selectivity addresses one of the critical failings of previous HER2-targeted T-cell engagers, which struggled with unintended damage to normal tissues.

Robert J. Markelewicz, Jr., Chief Medical Officer at Abpro Holdings Inc., noted that the preclinical evidence supports ABP-102/CT-P72 as a potential best-in-class therapy, given its ability to drive tumor-specific cytotoxicity while mitigating toxicity risks previously encountered with similar drug candidates.

How Does ABP-102/CT-P72 Improve Upon Previous HER2-Targeted Therapies?

The engineered structure of ABP-102/CT-P72 offers significant advances in both efficacy and safety. The molecule is designed using a tetravalent IgG1-[L]-scFv format, providing bivalent HER2 binding and functionally monovalent CD3 engagement. This configuration optimizes tumor targeting while minimizing unwanted activation of T-cells in healthy tissues.

Preclinical in vivo studies revealed that ABP-102/CT-P72 achieved up to a twofold increase in tumor suppression compared to a biosimilar of runimotamab, a benchmark HER2 x CD3 bispecific antibody. Importantly, dose escalation studies conducted in cynomolgus monkeys indicated a favorable safety profile, with ABP-102/CT-P72 being well tolerated at doses exceeding 180 times the maximum tolerated dose observed with the parental antibody.

Soo Young Lee, Senior Vice President and Head of the New Drug Division at Celltrion Inc., stated that ABP-102/CT-P72 represents a significant advancement in bispecific antibody technology, potentially overcoming the toxicity challenges that have historically limited HER2-targeted T-cell engager therapies.

Why Is Reduced Cytokine Release Important in Cancer Immunotherapy?

One of the longstanding challenges in T-cell engager therapies has been managing cytokine release syndrome, a potentially life-threatening side effect caused by excessive immune system activation. ABP-102/CT-P72 addresses this issue with a functionally monovalent CD3 binding design that significantly reduces cytokine release in HER2-low environments while maintaining potent cytotoxicity in HER2-high environments.

This attribute could be a decisive advantage in clinical trials, broadening the therapeutic window and enhancing tolerability for patients. By reducing cytokine-related toxicities without compromising antitumor efficacy, ABP-102/CT-P72 sets a new benchmark for the safety profiles expected from future HER2 x CD3 bispecific T-cell engagers.

When Will Clinical Trials for ABP-102/CT-P72 Begin?

Abpro Holdings Inc. and Celltrion Inc. plan to initiate clinical trials for ABP-102/CT-P72 in the first half of 2026. Given the strong preclinical data, expectations within the industry are high that the candidate could progress efficiently into human studies. The companies are targeting HER2-positive breast, gastric, pancreatic, colorectal, and potentially other tumor types that exhibit high HER2 expression levels.

How Does the ABP-102/CT-P72 Collaboration Fit Into Broader Oncology Trends?

The collaboration between Abpro Holdings Inc. and Celltrion Inc. reflects the accelerating pace of innovation in the bispecific T-cell engager space, particularly for HER2-positive cancers. Bispecific antibodies that can precisely direct T-cells to tumors while minimizing off-target effects are increasingly viewed as next-generation immunotherapy solutions.

Both companies have strategically aligned their development and commercialization efforts worldwide to maximize the potential reach of ABP-102/CT-P72. With Celltrion’s extensive manufacturing and global distribution network, and Abpro’s DiversImmune® platform for antibody development, the partnership positions itself strongly against existing and emerging competitors in the field of oncology therapeutics.

What Is the Current Sentiment Around Abpro and Celltrion Stocks?

Following the AACR 2025 announcement, Abpro Holdings Inc. experienced a modest share price increase of approximately 4.7% over the past five trading sessions, outperforming the Nasdaq Biotechnology Index. Analysts observe cautious optimism, recognizing the potential of ABP-102/CT-P72 while awaiting validation through clinical trial results. Short interest in Abpro remains moderately elevated at around 8.3%, highlighting a still-speculative outlook among traders.

Recent SEC filings indicate a slight net inflow into Abpro Holdings Inc. from small-cap focused biotech funds, signaling early-stage institutional accumulation. Long-term investors such as RA Capital Management and Perceptive Advisors have maintained or marginally increased their positions, reflecting guarded confidence in Abpro’s development pipeline. Current analyst consensus rates Abpro as a “Hold,” emphasizing the need for patience until Phase 1 clinical data become available.

Celltrion Inc., listed on the Korea Exchange under the symbol 068270, also saw a mild positive share price movement of approximately 1.2% over the past three sessions. Analysts maintain a “Moderate Buy” rating on Celltrion, citing its diversification beyond biosimilars into innovative therapeutics as a key long-term growth catalyst. Institutional flows into Celltrion remain strong, driven by domestic Korean pension funds and foreign institutional investors such as BlackRock and Vanguard Asia-Pacific funds.

FII activity around Celltrion remains robust, while DII flows are also supportive, with increased allocations from major Korean asset managers like Mirae Asset Global Investments and Samsung Asset Management. Given Celltrion’s expanding innovation pipeline, including ABP-102/CT-P72, it continues to strengthen its positioning within global healthcare investment portfolios.

For investors considering exposure, Abpro Holdings Inc. is positioned as a high-risk, high-reward opportunity suited for speculative biotech portfolios, while Celltrion Inc. offers a more balanced innovation-driven growth strategy with reduced downside risks. Analysts suggest a “Hold” on Abpro until clinical trial readouts and a “Moderate Buy” on Celltrion for medium to long-term investors seeking participation in next-generation oncology therapeutics.