TNF blockers range from $740 per recommended dose of Humira to $2,315 for Cimzia. As you can see, a 20-30% co-pay for these drugs is substantial. The average cost of biologics can run from $10,000 to $30,000 per year, and sometimes even more. While insurance may cover a portion of this cost, it will depend on your specific insurance plan. Doctor visits for ankylosing spondylitis can run between $300 and $400 per visit and physical therapy from $75-$150 per session.