TNF and infection: However, during the study, infections - including herpes zoster, and cancer, excluding non-melanoma skin cancer - were increased in patients taking tofacitinib: this should be monitored closely in subsequent studies.6 In a second study, a 6-month, randomized, double-blind, placebo-controlled, phase 3 trial of patients with PsA and inadequate response to TNF inhibitors, tofacitinib was used in a 5 mg twice daily dose or 10 mg twice daily dose.