A patent which is procured through “inequitable conduct” is unenforceable. Periodically, the C.A.F.C. states that the defense of inequitable conduct is over-utilized and, therefore, it is looked upon – by the C.A.F.C. – with “disfavor.” Of course, these pronouncements do not prevent the trial courts from finding inequitable conduct, nor the C.A.F.C. from affirming these findings. Most claims of inequitable conduct arise out of allegations that the patentee has withheld prior art from the patent examiner.