12 September 2017 - - Vancouver, British Columbia-based multifunctional biotherapeutics developer Zymeworks Inc. (NYSE: ZYME; TSX: ZYME) has provided an expanded dataset from the dose escalation portion of its Phase 1 study of ZW25, a novel Azymetric bispecific antibody targeting two distinct domains of the HER2 receptor, including a three-month follow-up for on-study patients as well as safety data on six new patients, the company said.
The best overall response in HER2-high, heavily pretreated breast cancer patients improved from two to four partial responses, resulting in a disease control rate of 63%. This included a partial response at each weekly dosing cohort.
ZW25 continues to be well-tolerated at all doses and schedules, with the most common adverse events being Grade 1 or 2 diarrhea, infusion reactions or nausea.
The dose escalation portion of the Phase 1 trial is complete and the new expansion cohorts have begun enrolling.
A total of 22 patients have been enrolled in the study, including 11 with breast cancer, eight with gastric, gastroesophageal junction, or esophageal cancer, and three with other HER2-expressing cancers.
ZW25 is Zymeworks' lead product candidate based on its Azymetric platform. It is a bispecific antibody that can simultaneously bind two non-overlapping epitopes of HER2, known as biparatopic binding, resulting in dual HER2 signal blockade, increased binding and removal of HER2 protein from the cell surface, and potent effector function.
These combined mechanisms of action have led to significant anti-tumor activity in preclinical models of HER2-expressing cancer. Zymeworks is developing ZW25 as a best-in-class HER2-targeting antibody intended as a treatment option for patients with any solid tumor that expresses HER2.
Zymeworks is dedicated to the discovery, development and commercialization of next-generation multifunctional biotherapeutics, initially focused on the treatment of cancer.
Its suite of complementary therapeutic platforms and its fully-integrated drug development engine provide the flexibility and compatibility to precisely engineer and develop highly-differentiated product candidates.