Are grants from a 501c charity for medical expenses taxable income?

I have leukemia and the drug I take costs many thousands of dollars each month. My Medicare Advantage insurance takes care of most of it.  However, the copay is over $500/month.  There is no way I can afford that.  I received a grant from Healthwell to cover the copay for 2015. They did no issue any kind of 1099, so is this medical assistance taxable?  Thanks for your help.