• Biological therapies using specific antibodies are being evaluated, with several protocols under investigation
  especially using interferon just before 5-FU + leucovorin . Injections of 5 to 10 million units of interferon three
  times a week in conjunction with 5-FU by infusion and direct injection has shown a high response rate (greater
  than 50 percent). This therapy may not be effective if it is used after the disease has progressed on 5-FU.
• Trials are comparing 5-FU + PALA versus 5-FU + interferon-alpha versus 5-FU + leucovorin. PALA + 5-FU
  has been reported to have responses better than 5-FU alone.