Is there a cure for overactive bladder?

Treatable. Overactive bladder cannot usually be cured but the symptoms can often be controlled by medication and other methods. Dietary measures such as decreasing acid and caffeine sometimes helps. There can be underlying causes which if addressed can help. A visit to a urologist will be helpful.
No. There are treatments but not really a cure. It is a condition that comes and goes and many treatments are available such as medications, injections, feedback therapy, and infusions.