Answer: What to do will really depend on what is eating the leaves. I suspect it may be a caterpillar about an inch long, commonly called the Euonymus caterpillar. If so, you may also see some fine webbing on the plants near the damaged areas. If the damage is limited you can prune it out and hopefully take the caterpillars with it. Otherwise you can spray with Bt or Bacillis thuringiensis. Here is a more detailed description and photo of the pest.
If this is not it, I would suggest you work with your local county extension to determine what is bothering your plant and based on knowing that, determine how to proceed. Good luck with your shrub!
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