- Results show overall confirmed objective response rate (cORR) of 33%, disease control rate (DCR) of 92%, and median progression-free survival (mPFS) of 9.6 months
- Data support further investigation of zanidatamab in combination with palbociclib and fulvestrant as a potential chemotherapy-free therapeutic option for patients with HER2-positive metastatic breast cancer and the trial is ongoing
Zymeworks Inc. (NYSE: ZYME), a clinical-stage biopharmaceutical company developing multifunctional biotherapeutics, today presented new clinical data for zanidatamab, the company’s investigational HER2-targeted bispecific antibody, in combination with palbociclib, a CDK4/6 inhibitor, and fulvestrant, a selective estrogen receptor degrader, in patients with heavily pretreated HER2-positive hormone-receptor positive metastatic breast cancer. The data were presented today in a spotlight poster session entitled Treatment of HER2-positive (HER2+) hormone-receptor positive (HR+) metastatic breast cancer (mBC) with the novel combination of zanidatamab, palbociclib, and fulvestrant during the San Antonio Breast Cancer Symposium (SABCS) taking place in San Antonio, Texas and virtually.
Clinical Data Highlights
The data presented at SABCS are from a clinical study of 45 patients with heavily pretreated HER2-positive HR-positive metastatic breast cancer who received zanidatamab in combination with palbociclib and fulvestrant. Patients had received prior regimens containing HER2-targeted agents including trastuzumab (100%), pertuzumab (80%), T-DM1 (98%), and other available options.
In 36 efficacy-evaluable patients, treatment with zanidatamab in combination with palbociclib and fulvestrant resulted in a cORR of 33% and DCR of 92%, and the majority of patients experienced a decrease in tumor size. The mPFS was 9.6 months with seven patients still on study at the time of data cutoff (August 31, 2022). The regimen was generally well-tolerated, with the majority of treatment-related adverse events considered mild to moderate in severity (Grade 1 or 2).
“Zanidatamab together with palbociclib and fulvestrant shows encouraging antitumor activity and a manageable tolerability profile in patients with HER2‑positive hormone-receptor positive breast cancer that has progressed after treatment with multiple HER2-targeted agents,” said Neil Josephson, M.D., Chief Medical Officer at Zymeworks. “We are encouraged by the durability of disease control and median progression-free survival in this heavily pretreated patient population indicating that this regimen has the potential to be developed as a chemotherapy-free treatment option for these patients.”
The presentation is available to conference registrants on the SABCS conference website and is also available on the publications page of the Zymeworks website at https://www.zymeworks.com/publications.
Title: Treatment of HER2-positive (HER2+) hormone-receptor positive (HR+) metastatic breast cancer (mBC) with the novel combination of zanidatamab, palbociclib, and fulvestrant
Lead Author: Santiago Escrivá-de-Romani, MD, Vall d’Hebron Institute of Oncology (VHIO), Vall d’Hebron University Hospital; Barcelona, Spain
Program Number: PD18-10
Zanidatamab is a bispecific antibody, based on Zymeworks' Azymetric™ platform, that can simultaneously bind two non-overlapping epitopes of HER2, known as biparatopic binding. This unique design results in multiple mechanisms of action including dual HER2 signal blockade, increased binding and removal of HER2 protein from the cell surface, and potent effector function leading to encouraging antitumor activity in patients. Zymeworks is developing zanidatamab in multiple Phase 1, Phase 2 and pivotal clinical trials globally as a targeted treatment option for patients with solid tumors that express HER2. Zymeworks has entered into separate agreements with each of BeiGene, Ltd. (BeiGene) and Jazz Pharmaceuticals Ireland Limited (Jazz), granting each of BeiGene and Jazz with exclusive rights to develop and commercialize zanidatamab throughout various counties around world.
About Zymeworks Inc.
Zymeworks is a clinical-stage biopharmaceutical company dedicated to the discovery, development and commercialization of next-generation multifunctional biotherapeutics. Zymeworks’ suite of therapeutic platforms and its fully integrated drug development engine enable precise engineering of highly differentiated product candidates. Zymeworks’ lead clinical candidate, zanidatamab, is a novel Azymetric™ HER2-targeted bispecific antibody currently being evaluated in multiple Phase 1, Phase 2, and pivotal clinical trials globally as a targeted treatment option for patients with solid tumors that express HER2. Zymeworks’ second clinical candidate, zanidatamab zovodotin (ZW49), is a novel bispecific HER2 ‑targeted antibody-drug conjugate currently in Phase 1 clinical development and combines the unique design and antibody framework of zanidatamab with Zymeworks’ proprietary ZymeLink™ linker and cytotoxin. Zymeworks is also advancing a deep preclinical pipeline in oncology (including immuno-oncology agents) and other therapeutic areas. In addition, its therapeutic platforms are being leveraged through strategic partnerships with global biopharmaceutical companies. For more information on our ongoing clinical trials visit www.zymeworksclinicaltrials.com. For additional information about Zymeworks, visit www.zymeworks.com and follow @ZymeworksInc on Twitter.
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