8-K: Zymeworks' Ziihera Receives FDA Accelerated Approval for HER2-Positive Biliary Tract Cancer

Zymeworks and Jazz Pharmaceuticals announce FDA accelerated approval of Ziihera for previously-treated, unresectable or metastatic HER2-positive biliary tract cancer.

Summary

• Zymeworks' drug Ziihera (zanidatamab-hrii) has received accelerated approval from the FDA for treating adults with previously-treated, unresectable or metastatic HER2-positive biliary tract cancer (BTC).
• The approval is based on a 52% objective response rate and a median duration of response of 14.9 months observed in the HERIZON-BTC-01 trial.
• This is the first FDA-approved therapy in Zymeworks' pipeline and the first dual HER2-targeted bispecific antibody approved for this indication.
• Zymeworks will receive a $25 million milestone payment from Jazz Pharmaceuticals due to the approval.
• The company is also eligible for up to $500 million in regulatory milestone payments and $862.5 million in commercial milestone payments, plus tiered royalties of 10% to 20% on net sales by Jazz.
• Continued approval may depend on verification of clinical benefit in the ongoing Phase 3 HERIZON-BTC-302 confirmatory trial.
• Zanidatamab is also being investigated in other tumor types, including Phase 3 trials for gastroesophageal adenocarcinomas and metastatic breast cancer.

Sentiment

Score: 8

Explanation: The document is highly positive due to the FDA approval, significant milestone payments, and promising clinical data. However, the risks associated with the confirmatory trial and potential side effects temper the overall sentiment slightly.

Positives

• Ziihera's accelerated FDA approval marks a significant milestone for Zymeworks, being their first FDA-approved therapy.
• The 52% objective response rate and 14.9-month median duration of response are promising results for patients with limited treatment options.
• The potential for up to $1.3625 billion in milestone payments and tiered royalties provides a strong revenue stream for Zymeworks.
• The approval validates Zymeworks' Azymetric bispecific platform technology.
• Zymeworks has a strong balance sheet and anticipates revenue from zanidatamab, which will allow them to accelerate their wholly-owned R&D programs.
• The company's cash runway is projected into the second half of 2027.

Negatives

• Continued approval for Ziihera is contingent upon verification of clinical benefit in the ongoing Phase 3 confirmatory trial.
• Ziihera carries warnings for embryo-fetal toxicity, left ventricular dysfunction, infusion-related reactions, and diarrhea.
• Serious adverse reactions occurred in 53% of patients, including biliary obstruction, biliary tract infection, and sepsis.
• A fatal adverse reaction of hepatic failure occurred in one patient.

Risks

• The ongoing Phase 3 confirmatory trial may not verify the clinical benefit of Ziihera, potentially impacting its continued approval.
• Ziihera has several potential side effects, including embryo-fetal toxicity, left ventricular dysfunction, infusion-related reactions, and severe diarrhea.
• The company's financial projections and cash runway are based on assumptions that may not be accurate.
• The company may not achieve all milestone payments or receive the full potential royalties.
• Regulatory agencies may impose additional requirements or delay the initiation of clinical trials.
• The commercialization of zanidatamab may not be successful.

Future Outlook

Zymeworks anticipates continued revenue from its collaboration with Jazz Pharmaceuticals and plans to use these funds to accelerate the development of its wholly-owned R&D programs. The company expects to have a cash runway into the second half of 2027. They also plan to submit investigational new drug applications for multiple new product candidates in 2025, 2026 and beyond.

Management Comments

• Paul Moore, Ph.D., Chief Scientific Officer at Zymeworks, stated that the approval exemplifies the team's exceptional scientific capabilities and offers new hope for patients with unresectable or metastatic HER2-positive BTC.
• Kenneth Galbraith, Chair and Chief Executive Officer of Zymeworks, noted that the collaboration with Jazz provided the optimal partner to continue the rapid advancement of zanidatamab and that the company is encouraged by Jazz's continued investment in the therapy.
• Kenneth Galbraith also stated that the combination of a strong balance sheet and anticipated revenue stream associated with zanidatamab positions the company to accelerate the development of its wholly-owned R&D programs.

Industry Context

This announcement is significant as it marks the first FDA approval for a dual HER2-targeted bispecific antibody for biliary tract cancer, a disease with limited treatment options. It highlights the growing importance of bispecific antibodies in oncology and the potential of Zymeworks' Azymetric technology. The approval also underscores the value of strategic collaborations in bringing novel therapies to market.

Comparison to Industry Standards

• The 52% objective response rate for Ziihera is notable compared to historical outcomes for previously treated HER2-positive biliary tract cancer, where response rates to chemotherapy are typically much lower.
• While direct comparisons are difficult due to varying trial designs, the 14.9-month median duration of response is encouraging, suggesting a meaningful clinical benefit for patients.
• Other companies like Roche with Herceptin and Perjeta have targeted HER2 in other cancers, but Ziihera is the first bispecific antibody approved for HER2-positive BTC, representing a novel approach.
• The ongoing Phase 3 trial will be crucial in confirming these results and establishing Ziihera as a standard of care in the first-line setting, potentially competing with existing chemotherapy regimens.

Stakeholder Impact

• Shareholders will benefit from the potential revenue stream and validation of Zymeworks' technology.
• Patients with HER2-positive biliary tract cancer will have a new treatment option.
• Employees of Zymeworks will be involved in the continued development and commercialization of Ziihera.
• Jazz Pharmaceuticals will benefit from the exclusive rights to commercialize zanidatamab in their territories.

Next Steps

• Zymeworks will continue the Phase 3 HERIZON-BTC-302 confirmatory trial to evaluate zanidatamab in combination with standard-of-care therapy.
• The company will advance zanidatamab in other tumor types, including Phase 3 trials for gastroesophageal adenocarcinomas and metastatic breast cancer.
• Zymeworks will host an in-person and virtual R&D day on December 12, 2024, to provide updates on its portfolio.
• The company plans to submit investigational new drug applications for multiple new product candidates in 2025, 2026 and beyond.

Key Dates

Keywords

Ziihera, zanidatamab, HER2-positive, biliary tract cancer, FDA approval, bispecific antibody, oncology, milestone payments, Jazz Pharmaceuticals, Azymetric technology