Zymeworks' Zanidatamab (Ziihera) Receives FDA Approval for HER2-Positive Biliary Tract Cancer
Key Insights
Zymeworks' partnered drug, zanidatamab (now Ziihera), has gained FDA approval for treating HER2 (search)-positive metastatic biliary tract cancer (BTC).
This marks the first bispecific antibody and chemotherapy-free option for this rare and aggressive cancer, affecting approximately 16,000 new patients annually in the US.
The approval triggers a $25 million milestone payment to Zymeworks from Jazz Pharmaceuticals, with potential for further payments based on regulatory and commercial success.
Jazz Pharmaceuticals' Ziihera (zanidatamab), developed in partnership with Zymeworks, has received FDA approval for the treatment of HER2 (search)-positive metastatic biliary tract cancer (BTC) in adults. This approval marks a significant milestone for Zymeworks, a Canadian biotech company, and provides a new treatment option for patients with this rare and aggressive cancer.
First Bispecific Antibody for BTC
Ziihera is the first bispecific antibody approved for BTC and offers a chemotherapy-free regimen for patients with HER2 (search)-positive tumors. Biliary tract cancer affects approximately 16,000 new patients annually in the US and is often diagnosed at a late stage, resulting in poor prognosis. The approval addresses a critical unmet need for effective therapies in this patient population.
"Words can’t describe how happy and humbled I feel," said Zymeworks co-founder and ex-chief executive officer Ali Tehrani in a LinkedIn post. FDA approval "was the dream that many said was not possible" when the company started in 2003. "Today it became reality – most importantly for patients who will benefit from it."
Financial Implications for Zymeworks
The FDA approval triggers a $25 million milestone payment to Zymeworks from Jazz Pharmaceuticals, as part of a licensing deal struck in 2022. The agreement also includes potential for up to $500 million in additional payments for regulatory milestones and $862.5 million for commercial milestones. Furthermore, Zymeworks is eligible to receive royalties of 10% to 20% of net sales from related products.
Zanidatamab's Potential Beyond Biliary Tract Cancer
Zanidatamab is currently undergoing advanced human trials to evaluate its efficacy in treating gastric cancer (search) and other subsets of biliary cancer. David Martin, an analyst with Bloom Burton & Co., estimates that these additional indications could expand the drug's global peak sales to $750 million. Jazz Pharmaceuticals anticipates that peak sales for zanidatamab-based treatments, including potential applications in breast cancer (search), could reach $2 billion.
"The fact the drug has been approved for this first indication gives increased confidence for other indications," Mr. Martin said. "It’s proof of concept that their antibody generating platform technologies can be successful" in generating marketable drugs.
Zymeworks' Strategic Shift
Following a period of financial instability and leadership changes, Zymeworks has refocused its strategy on developing a pipeline of cancer drugs. Kenneth Galbraith, the current CEO, aims to bring five new medicines to the clinic within five years, with a focus on antibody-drug conjugates and T-cell engager molecules targeting solid tumors. The FDA has already cleared two of Zymeworks' drugs for clinical trials, and the company plans to unveil its fifth candidate next month.