Zymeworks plans to take second drug into trials in HER2-expressing cancers

ZW49 was developed by leveraging ZymeLink in combination with Zymeworks’ flagship Azymetric bispecific platform. The Company expects to file an Investigational New Drug (IND) application this year in order to begin clinical trials with ZW49 for patients with HER2-expressing cancers.

ZW49 is a novel bispecific ADC targeting two distinct domains of the HER2 receptor resulting in enhanced internalization and delivery of its proprietary ZymeLink cytotoxic payload. ADCs incorporating ZymeLink have demonstrated a greater therapeutic window (range of doses that are both efficacious and tolerable) in preclinical testing than those incorporating the commonly used ADC payloads DM1 or MMAE.

As a result, ZW49 exhibited superior activity when assessed against other approved HER2-targeted therapies and Zymeworks’ previous internal ADC candidate, ZW33. Consequently, the Company will advance ZW49 in lieu of ZW33. Preclinical data on ZW49 and more generally on the ZymeLink ADC platform will be presented at the annual meeting of the American Association for Cancer Research to be held April 2018 in Chicago. Abstracts for these preclinical data were published today.

Zymeworks president and CEO Ali Tehrani said: “The data generated by ZW49 clearly supported its designation as our second product candidate for clinical evaluation.

“With the addition of the complementary ZymeLink technology, including proprietary linkers and payloads, we have been able to further leverage the power of our Azymetric platform to create a differentiated molecule that we believe has the potential for best-in-class activity and tolerability.”

Zymeworks, whose protein engineering expertise and resulting therapeutic platforms have resulted in a network of global biopharmaceutical partners, is keenly focused on developing its own portfolio of product candidates. Its lead compound, ZW25, is currently being assessed in an adaptive Phase 1 clinical trial and has shown promising single-agent anti-tumor activity in patients with heavily pretreated HER2-expressing cancers that have progressed after standard of care.

Zymeworks continues to accelerate the development of ZW25 and is opening several new clinical sites across North America in 2018.

Zymeworks chief medical officer Diana Hausman said: “With the advancement of ZW49, we now have a portfolio of agents with the potential to address the full spectrum of patients with HER2-expressing cancers.

“This includes those underserved patients whose tumors express lower levels of HER2 and are ineligible for treatment with HER2-targeted therapies, such as trastuzumab, pertuzumab, and T-DM1.”