Jazz Pharmaceuticals announced Friday that its cancer treatment Zepzelca did not achieve its primary objective of extending patient survival in a comprehensive late-stage clinical trial, putting its existing regulatory approval at potential risk.
The pharmaceutical company’s stock price dropped almost 2% during pre-market trading following the announcement.
Jazz Pharmaceuticals reported that it has provided the study findings to the U.S. Food and Drug Administration and plans to engage in discussions about future requirements related to the medication’s second-line treatment designation.
The drug currently maintains accelerated FDA approval for treating patients with advanced small cell lung cancer (SCLC) when used as a second-line therapy, meaning it’s given after initial treatments have proven unsuccessful.
Small cell lung cancer represents an particularly aggressive cancer type that has the ability to metastasize throughout the body, including to bone marrow tissue.
The comprehensive confirmatory study evaluated Zepzelca’s effectiveness both when administered alone and when combined with traditional chemotherapy treatments.
Study results showed that patients receiving Zepzelca as a standalone treatment survived for a median duration of 8.7 months, while those receiving the combination approach lived for 10.9 months, compared to 10.7 months for participants in the control group.
Additionally, federal regulators had granted Zepzelca approval in 2025 for use alongside Roche’s immunotherapy medication Tecentriq as a maintenance treatment for adult patients with extensive-stage SCLC whose condition remained stable following initial chemotherapy.
