Targeting T-cell subsets to achieve remission

Biologic Therapeutics in the Treatment of Psoriasis. Part 1: Review

Background:

Psoriasis is a chronic inflammatory skin disease principally mediated by activated T cells, which release proinflammatory cytokines with reactive epidermal changes in the skin, producing the characteristic lesions of psoriasis. New research into possible treatment options has been inspired by increased understanding of the pathophysiology of psoriasis and advances in immunology and molecular biology permitting the development of targeted, highly active biologic agents.

Objective:

The aim of this article is to review the efficacy and safety of five biologic therapeutics in the treatment of moderate to severe psoriasis and to provide practical guidelines for integration of these agents in the management of psoriasis.

Methods:

We searched MEDLINE (1966–2005) for articles containing the key words: alefacept, efalizumab, etanercept, infliximab, and adalimumab and searched recent conference abstracts.

Results:

Emerging immunotherapeutic agents (fusion proteins, recombinant cytokines, fusion toxins, or antibodies) target T cells or cytokines responsible for plaque formation that is characteristic of psoriasis. Alefacept is the first biologic to be approved in both the United States and Canada. More recently, efalizumab and etanercept and infliximab have been approved in the United States and Canada for plaque-type psoriasis. Adalimumab is currently in phase III clinical trials.

Conclusion:

These novel biologics offer an intriguing and effective treatment option for patients with moderate to severe psoriasis.

Safety and efficacy of alefacept, efalizumab, etanercept and infliximab in treating moderate to severe plaque psoriasis: a meta-analysis of randomized controlled trials

BACKGROUND

The relatively recent introduction of biological agents to treat psoriasis presents clinicians with the need to objectively compare and contrast these agents to allow more effective treatment of their patients.

OBJECTIVES

To evaluate and compare the efficacy and safety of biological agents in the treatment of plaque psoriasis.

METHODS

(i)

DATA SOURCES

Four parallel systematic reviews conducted through July 2006, including peer-reviewed data and U.S. Food and Drug Administration (FDA) reports. (ii)

STUDY SELECTION

Randomized, controlled, double-blind, monotherapy trials of alefacept (n = 3), efalizumab (n = 5), etanercept (n = 4) and infliximab (n = 4); 16 studies comprising 7931 patients met inclusion criteria. (iii)

DATA EXTRACTION

Efficacy was measured by Psoriasis Area and Severity Index (PASI) 75 achievement after 10-14 weeks of treatment, using intention-to-treat analysis. Safety was evaluated by the incidence of one or more adverse event(s) (AEs) and serious adverse event(s) (SAEs) during 10-30 weeks of treatment.

RESULTS

Pooled relative risk (RR) and number needed to treat (NNT) of PASI 75 achievement compared with placebo was computed using Mantel-Haenszel methods and the random effects model. All biological agents for psoriasis were efficacious (P < 0.001); however, there was a graded response for achievement of PASI 75: infliximab (RR = 17.40, NNT = 2), etanercept (RR = 11.73, NNT = 3), efalizumab (RR = 7.34, NNT = 4) and alefacept (RR = 3.70, NNT = 8). The risk of one or more AEs was evaluated by RR and number needed to harm (NNH). This was increased in the alefacept (RR = 1.09, P = 0.03, NNH = 15), efalizumab (RR = 1.15, P < 0.001, NNH = 9) and infliximab (RR = 1.18, P < 0.001, NNH = 9) groups compared with placebo. SAEs were increased in a sensitivity analysis of four efalizumab trials (n = 2443, RR = 1.92, P = 0.03, NNH = 60).

CONCLUSIONS

The decreasing rank order for pooled efficacy was infliximab, etanercept, efalizumab and alefacept when compared with placebo. Pooling safety data revealed a previously unreported increased risk of AEs for alefacept, efalizumab and infliximab.

A reappraisal of the concept of suppressive versus remittive psoriasis treatments

Among the ways to characterize the many treatments for psoriasis is to distinguish suppressive from remittive therapies. Remittive therapies are thought to be treatments that result in a prolonged period of disease remission even after stopping the drug, while suppressive treatments are thought to work only during the treatment period. However, apparent differences in remittive and suppressive properties may be due to the remitting and relapsing nature of psoriasis and the order in which treatments are used in patients. Few clinical trials have compared the suppressive versus remittive properties of different treatments. Given the adverse events and expense associated with many psoriasis therapies, a major implication is that psoriasis patients who have cleared on therapy should probably be tested at intervals to see if they can be tapered off their medication without loss of control of their disease.