Zymeworks Presents New Preclinical Data on Antibody-Drug Conjugate Programs at EORTC-NCI-AACR Conference
ZYME 10.25.2024

About Gravity Analytica
Recent News
- 01.16.2025 - 43rd Annual J.P. Morgan Healthcare Conference
- 01.08.2025 - Zymeworks Outlines Strategic Priorities and Outlook for 2025 and 2026
- 12.12.2024 - Zymeworks Hosts R&D Day Highlighting Continued Clinical Progress in Oncology Programs and Expansion into Autoimmune and Inflammatory Diseases
Recent Filings
- Presentations highlight key preclinical data that support investigational new drug application (IND) submissions for ZW220 in 1H and ZW251 in 2H in 2025
"We are thrilled to present preclinical data for ZW220 and ZW251 at the
Oral Presentation Details
An oral presentation titled “ZW220, a NaPi2b-directed topoisomerase I inhibitor Antibody-Drug Conjugate, demonstrates compelling preclinical activity in NSCLC, ovarian and uterine cancer models, with a favorable toxicology profile in non-human primate” highlights preclinical data that continue to support an IND submission in the first half of 2025.
Results demonstrate that ZW220 has the potential for improvement over previous NaPi2b ADCs and on the basis of efficacy, tolerability and payload mechanism. ZW220 features a novel, moderate potency TOPO1i payload with strong bystander activity, beneficial for tumors with low and heterogeneous NaPi2b expression. We believe it offers a differentiated safety profile compared to other ADCs currently in the clinic, demonstrating high tolerability in animal studies with MTD ≥90 mg/kg in non-human primates (NHP) and ≥200 mg/kg in rats, suggesting potential for high doses in humans. The low drug-antibody ratio (DAR) and moderate stability of the antibody-linker provide a good balance of stability, tolerability, and anti-tumor activity, while potentially minimizing antibody-driven toxicities. ZW220's strong internalizing antibody enables efficient cellular trafficking and tissue penetration, potentially improving anti-tumor activity even at lower NaPi2b levels.
Poster Presentation Details
A poster titled “ZW251, a novel glypican-3-targeting antibody-drug conjugate bearing a topoisomerase I inhibitor payload,demonstrates compelling preclinical activity in hepatocellular carcinoma models” highlights preclinical data that continue to support an IND submission in the second half of 2025.
Results demonstrate that ZW251 shows promise as a new treatment option for patients, potentially improving upon the current standard of care (SOC). Demonstrating strong anti-tumor activity across a wide range of hepatocellular carcinoma (HCC) models, including those with lower and heterogenous GPC3 expression, ZW251 was designed with a DAR of four, striking a balance between tolerability and broad anti-tumor effectiveness. In NHP studies, ZW251 displayed significant tolerability at doses up to 120 mg/kg. As an ADC, ZW251 offers flexibility in treatment strategies, potentially serving as either a standalone therapy or in combination with existing SOC treatments.
About ZW220
ZW220 is an ADC that targets NaPi2b-expressing NSCLC and ovarian cancers, and is built, like ZW191, using our proprietary TOPO1i- payload technology. The NaPi2b-targeting monospecific antibody incorporated in ZW220 was developed in-house and selected based on a favorable binding profile and enhanced internalization properties to enable targeting of both high- and low- NaPi2b-expressing tumors. The antibody in ZW220 is Fc-silenced, containing mutations in its Fc region which abolish FcγR (Fc gamma receptor) binding in normal cells, with the goal of minimizing potential off-target toxicities. A DAR of four and a moderate stability antibody-linker were selected to balance tolerability and efficacy. NaPi2b is reported to be expressed in approximately 96% of ovarian serous adenocarcinoma and 87% of non-small cell lung cancer (NSCLC) adenocarcinoma1, and ZW220 has demonstrated anti-tumor activity in patient-derived xenograft models and robust growth inhibition in 3D spheroid models of these cancers. The bystander effect of the TOPO1i payload may help address NaPi2b heterogeneity across these cancers. ZW220 is well-tolerated in non-human primates (NHP) and rats, reaching maximum tolerated doses (MTDs) of ≥ 90 mg/kg and ≥ 200 mg/kg, respectively. We expect to submit an investigational new drug application (IND) and non-
About ZW251
ZW251, a potential first-in-class ADC molecule designed for the treatment of glypican 3 (GPC3)-expressing HCC, incorporates the same
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Forward Looking Statements
This press release includes “forward-looking statements” or information within the meaning of the applicable securities legislation, including Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. Forward-looking statements in this press release include, but are not limited to, statements that relate to anticipated preclinical data presentations; the timing and status of ongoing and future studies and the release of data; expectations regarding future regulatory filings and approvals and the timing thereof; the timing of and results of interactions with regulators; Zymeworks’ preclinical pipeline; the anticipated benefits of the collaboration agreements with Jazz and BeiGene; the commercial potential of technology platforms and product candidates; Zymeworks’ clinical development of its product candidates and enrollment in its clinical trials; the potential addressable market of zanidatamab; potential safety profile and therapeutic effects of zanidatamab and Zymeworks’ other product candidates; the ability to advance product candidates into later stages of development; and other information that is not historical information. When used herein, words such as “plan”, “believe”, “expect”, “may”, “anticipate”, “potential”, “will”, “continues”, and similar expressions are intended to identify forward-looking statements. In addition, any statements or information that refer to expectations, beliefs, plans, projections, objectives, performance or other characterizations of future events or circumstances, including any underlying assumptions, are forward-looking. All forward-looking statements are based upon Zymeworks’ current expectations and various assumptions.
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1Linet al. 2015.
2Wang HL et al., Arch Pathol Lab Med 2008

Source: Zymeworks Inc.