Zactima
Meaning of Zactima: A brand name that never launched: the drug behind it survived, changed disease, and reached the market under another name.
Definition of Zactima
Zactima was the proposed brand name for vandetanib during the trials that tested it against lung cancer. Vandetanib is a tyrosine kinase inhibitor, a targeted drug that blocks several enzymes tumors depend on for growth and for building new blood vessels. The lung cancer program did not lead to approval, and the drug reached the market later under a different name for a different disease.
What does vandetanib block?
| Target | What it normally does | Effect of blocking it |
|---|---|---|
| VEGF receptor | Signals the growth of new blood vessels | Starves a tumor of the supply it needs to enlarge |
| EGF receptor | Drives cell growth and division | Slows proliferation in tumors that depend on that signal |
| RET | A growth switch, faulty in certain thyroid cancers | Removes the signal driving those tumors |
Blocking the first of these makes the drug a form of antiangiogenesis treatment, and blocking the other two makes it a growth-signal blocker, so it works on two fronts at once. That combination is what separates it from conventional chemotherapy, which damages any rapidly dividing cell without regard to which signal is driving it.
Why did the lung cancer program stop?
Vandetanib was tested in advanced non-small cell lung cancer, alone and alongside chemotherapy. Some measures moved, including the time before the disease grew again, but overall survival did not improve enough to support approval, and the marketing applications for lung cancer were withdrawn. That ending is common for a targeted drug given to an unselected group. A molecularly targeted therapy can only help when the target it blocks is the fault actually driving the tumor, and lung cancers as a class are driven by many different faults, most of which vandetanib does not touch. Later drugs in the same field were tested only in people whose tumors carried the matching fault, and fared very differently.
What is it approved for now?
Vandetanib is approved as Caprelsa for advanced medullary thyroid cancer, an uncommon cancer arising not from the hormone-producing follicles of the thyroid but from the cells that make calcitonin. A large share of these tumors are driven by a faulty RET gene, which is precisely one of the targets vandetanib blocks, so the drug found its use in the disease that matched its mechanism. Its label carries a prominent warning about lengthening the electrical recovery time of the heart, which can trigger a dangerous rhythm, and access is managed through a restricted program for that reason. The name Zactima now appears mainly in older trial reports.
Also known as
Used in a sentence
Vandetanib, studied under the name Zactima, was evaluated in clinical trials for advanced lung cancer.
Good to know
Zactima names vandetanib's lung cancer development program, which did not result in approval for that disease, whereas the same drug is approved under the name Caprelsa for advanced medullary thyroid cancer.