I think it depends on why Asacol didn't work. If you think that the Asacol wasn't breaking down properly, and therefore, not releasing the mesalamine (the active ingredient), then yes, there's probably a good chance Apriso would work. Apriso starts dissolving at a lower pH than Asacol, and there is some evidence suggesting that people with UC have a lower gut pH. However, if Asacol didn't work because your UC doesn't respond to mesalamine, then there's not much chance Apriso would work. I'd for sure talk it over with your doc.
Status: Remission since May 2009!
Symptoms began in November 2008, ~4 weeks after giving birth to my son
Diagnosed with pancolitis on 1/30/09
Meds: Apriso (4 0.375g pills ONCE!! daily), mesalamine enema twice weekly, Natural Factors Ultimate probiotic 12/12 Formula, multivitamin. Used prednisone (starting dose 40 mg) to get into remission.