Nail psoriasis was present in the majority (92 percent) of the 373 patients enrolled in an international, phase 3, randomized, placebo-controlled study investigating infliximab for the treatment of moderate-to-severe chronic plaque psoriasis. Infliximab was significantly superior to placebo for improving Nail Psoriasis Severity Index scores. Approximately one-fourth of infliximab-treated patients achieved clearing of nail psoriasis by week 24, and that proportion nearly doubled by week 50.
Phoebe Rich, M.D., reports the findings on the effects of infliximab on nail psoriasis. EXPRESS randomized 373 patients 4:1 to treatment with infliximab 5 mg/kg (induction at weeks zero, two and six, followed by maintenance every eight weeks) or placebo. At week 24, patients in the placebo group were crossed over to receive infliximab induction and maintenance, and treatment continued in both study groups through week 46.
Of the patients who entered the study, 305 (92 percent) had nail psoriasis. Each patient had an average of approximately 7.5 affected nails. Nail disease response was assessed using the Nail Psoriasis Severity Index (NAPSI) to rate the worst nail at baseline. Possible NAPSI scores range from 0 (clear) to 8.
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The improvement in NAPSI score persisted in the infliximab group through week 50, while the control patients who were crossed over to infliximab at week 24 demonstrated an approximate 80 percent improvement in NAPSI score by the end of the study.
"A benefit of infliximab for improving nail psoriasis has been previously reported. These data from EXPRESS corroborate those findings in a large population of patients and demonstrate that the clearing is sustained with ongoing treatment," says Dr. Rich, a recognized expert on nail disease and clinical associate professor of dermatology, Oregon Health Sciences University, Portland.
Infliximab was associated with significant improvements in NAPSI scores for the nail matrix and nail bed compared with placebo. At week 24, the nail matrix NAPSI score had improved by 52.9 percent in the infliximab group and worsened by 1.9 percent in the placebo-treated patients. Nail bed scores improved in the infliximab and placebo patients at week 24, 69.2 percent and 18.4 percent, respectively.
"Lunular red spots were the nail matrix feature that improved most rapidly with infliximab treatment, and regarding nail bed features, the fastest improvement was seen in splinter hemorrhages. Both of those disease signs had cleared in about two-thirds of infliximab patients by the time they were receiving the last of the three induction doses," Dr. Rich says.
By week 10, nearly 7 percent of infliximab patients achieved clearance of all signs of psoriasis in the target nail. The proportion achieving clearing rose to 26.2 percent at 24 weeks and increased to 44.7 percent at week 50.
"Resolution of pitting and other signs of nail psoriasis requires that the diseased nail be replaced with new healthy nail, and so clearance of nail psoriasis is limited by nail growth. The progression in nail improvement observed with infliximab treatment parallels the normal nail growth rate," Dr. Rich says.
Dr. Rich notes that treatment of nail psoriasis is an important concern because of the psychosocial impact of the condition.
"Nail psoriasis is very distressing to affected individuals who may be embarrassed by the appearance of their nails or find their efforts to shake hands are rejected by people who are afraid the psoriasis patient has some contagious disease. The emotional burden of nail psoriasis can be just as great as that associated with skin disease, and so it is important that clinicians take treatment of nail psoriasis seriously," Dr. Rich says.
Historically, however, treatment of nail psoriasis has presented a challenge. Since efficacy requires penetration into the nail matrix, topical treatments do not work well. Direct injection of corticosteroids into the nailfold can be effective. However, that approach is less than satisfactory because of low patient acceptance, the need for multiple monthly injections and the risk of disease flares after the treatment stops, Dr. Rich says.
"Conventional systemic therapies, including acitretin, methotrexate and cyclosporine A are also effective in clearing nail disease, but can cause significant toxicity. The biologics have been very helpful for treating nail disease, as well as skin psoriasis," she says.
DISCLOSURES: Dr. Rich has been an investigator for Centocor and other companies that market biologic treatments for psoriasis. She is also a consultant to Centocor.