Key messages

• It is not clear whether biological therapy has a role in the treatment of nail psoriasis because the certainty of the evidence is very low

What is the evidence.
See evidence matrix  in Epistemonikos later

We found two systematic reviews [1],[2] that include five primary studies reported in 10 references [3],[4],[5],[6],[7],[8],[9],[10],[11],[12], of which three (eight references [3],[4],[5],[6],[7],[8],[9],[10]) correspond to randomized controlled trials.

This table and the overall summary are based on the latter.

What types of patients were included

All studies included adult patients, over 18 years old, of both sexes, with nail psoriasis and no other nail disease.

Two studies included patients with moderate to severe psoriasis with at least 6 months from diagnosis and Psoriasis Area and Severity Index (PASI) > 12 [5],[6].

One study included patients with active psoriatic arthritis [4]. Studies of patients with pustular psoriasis of the nails, acropustulosis keratotica and acrodermatitis continua of Hallopeau were excluded. 

What types of interventions were included

One study evaluated subcutaneous golimumab 50 or 100 mg at weeks 0, 4, 8, 12, 16 and 20 [4]; patients that at week 16 had less than 10% improvement had an escalation of therapy (placebo to golimumab 50 mg or golimumab 50 mg to 100 mg). It was compared with placebo at week 24 and then a crossing over was done to complete 24 more weeks.

One study used subcutaneous ustekinumab 45 mg or 90 mg at weeks 0 and 4 and then every 12 weeks until week 52 [5]. Patients with improvement <50% in PASI at 28 weeks discontinued the intervention. This was compared to placebo at weeks 0 and 4, and then a crossover to ustekinumab 45 or 90 mg at week 12 was performed, administering treatment at week 16, 28, 40 and 52.

One study used intravenous infliximab 5mg/kg at week 0, 2 and 6 and every 8 weeks up to week 46 [6]: This was compared against placebo until week 24 and then crossing over to infliximab 5 mg/kg on week 24, 26 and 30 and then every 8 weeks to complete.

What types of outcomes
were measured

Nail psoriasis was measured in all studies with Nail Psoriasis Severity Index (NAPSI) in the most affected nail. Overall improvement in nail psoriasis by clinical assessment and the degree of improvement according to patient’s opinion were also assessed.

Other outcomes were: adverse effects, quality of life and improvement on nail features (pain, thickness, hyperkeratosis, number of affected nails and growth).

We found three systematic reviews [5], [6], [7], including 14 studies   reported in 21 references [8], [9], [10], [11], [12], [13], [14], [15], [16],   [17], [18], [19], [20], [21], [22], [23], [24], [25], [26], [27], [28]. Eight   studies correspond to randomized controlled trials (15 references [9], [10],   [11], [12], [13], [14], [16], [17], [19], [21], [22], [23], [24], [26], [27]).   This table and the summary in general are based on the latter. One study [15]   did not contribute data to any of the outcomes of interest.

To whom this evidence does and does not apply

• The evidence presented in this summary is generally applicable to all adult patients with nail psoriasis.
• Does not apply to patients with other nail diseases or with pustular psoriasis of the nails, acropustulosis keratotica or acrodermatitis continua of Hallopeau.

• Nail Psoriasis Severity Index (NAPSI) measured in the most affected nail was the outcome selected because it was the only outcome measured in all three studies to determine the severity of nail psoriasis, and corresponds to a critical outcome for decision making.

• In general, the certainty of the available evidence is very low so it is not possible to make an adequate risk/benefit balance.
• Adverse effects are more common in biological therapies compared to placebo, although these are not serious.

• Due to the existence of other effective therapeutic measures in this condition it is likely that most patients would not be inclined to use an intervention of high cost and adverse effects associated with an uncertain benefit. 

• There were no costs reported in the studies included in our summary, but these are generally high cost drugs. The uncertainty regarding the possible benefits makes impossible to estimate the cost/benefit relation.

Differences between this summary and other sources

• The findings of our summary are consistent with those of the systematic reviews identified.
• The conclusions of this summary are in partial agreement with the British Association of Dermatologists' guideline for biologic interventions for psoriasis [13], which refers infliximab as an intervention for nail psoriasis. However, the criteria for the use of this type of treatment does not include nail psoriasis and would be indicated for patients with severe disease (PASI score ≥ 10 or DLQI > 10) plus one of the following characteristics: phototherapy or systemic therapy are contraindicated, not tolerated, or disease is refractory to such treatments. It would also be indicated for patients with joint involvement that have been refractory or have contraindications to standard systemic therapy. 

• The probability that the main findings of this summary change with future evidence are very high due to the very low certainty of the evidence so far.
• Unfortunately we did not identify ongoing studies evaluating this intervention against placebo, but new studies focusing on the comparison of one biologic to another.