TNF and rheumatoid arthritis: Cases of RA and Crohn's disease that become refractory to infliximab over time often respond well to adalimumab.26,29–32 In fact, the level of therapeutic efficacy achieved with adalimumab in infliximab-resistant patients is comparable to the improvement achieved when adalimumab is used in TNF-α-inhibitor–naïve patients.29,31 Thus, adalimumab may be a valuable treatment for PG patients who fail to respond to infliximab and other conventional immunosuppressive regimens.