FDA's drug approvals database lists a supplement to the new drug application for tucatinib (TUKYSA, Seagen), dated 7 October 2026. The database entry does not state what the supplement changed; supplements can cover labelling, manufacturing or indication changes, and most are administrative.
For prescribers, the interaction profile is the part of tucatinib that matters day to day. It is a strong CYP3A inhibitor, so sensitive CYP3A substrates with narrow margins need dose reduction or avoidance. It is metabolised mainly by CYP2C8, so strong CYP2C8 inhibitors such as gemfibrozil raise its levels. It also raises serum creatinine by blocking tubular secretion without reducing true glomerular filtration.
Check the current label for the specific change before acting on it. No Indian regulatory action is recorded here.
- Check the current tucatinib label for what this supplement altered
- Review co-prescribed CYP3A substrates, such as some statins and immunosuppressants, when tucatinib is started
- Avoid strong CYP2C8 inhibitors such as gemfibrozil alongside tucatinib
- Interpret a modest creatinine rise on tucatinib with care; consider cystatin C before calling it kidney injury
Why it matters
Tucatinib's interactions and creatinine effect are easy to misread outside oncology.
Don't overread it
A licence supplement is not a new indication, and the database entry does not say what changed.
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