FRIDAY, April 18 (HealthDay News) -- A new drug for patients with moderate to severe psoriasis appears to be safe and effective, a Canadian trial shows.

The results indicate higher doses of ISA247, which is a calcineurin inhibitor, significantly improve symptoms of psoriasis. Calcineurin is a protein that helps regulate inflammation.

"This is the first oral medication in 20 years to show promise for the treatment of moderate to severe plaque psoriasis," said lead researcher Dr. Kim Papp, from Probity Medical Research in Waterloo, Ontario.

The new drug is safer and easier to use than current treatments for psoriasis, the researchers said.

Psoriasis is an autoimmune skin disease. The most common form, plaque psoriasis, appears as raised, red patches or lesions covered with a silvery white buildup of dead skin cells. As many as 7.5 million Americans have psoriasis, according to the U.S. National Institutes of Health.

Currently, one of the most effective treatments for psoriasis is the calcineurin inhibitor drug ciclosporin. However, the drug's toxic effects on the kidneys prevent it from being used for long-term treatment, which is often needed because psoriasis tends to reappear once treatment is stopped.

Other drugs such as infliximab (Remicade) are safe and effective but are expensive and inconvenient to use. In addition, the long-term safety of the drug isn't known.

The report is published in the April 19 issue of The Lancet.

In the study, Papp's team randomly selected 451 patients with plaque psoriasis that affected at least 10 percent of the body, to receive the new drug or placebo. There were three groups of patients who received ISA247, but at different doses.

The researchers looked for a 75 percent reduction in what is called the psoriasis area and severity index score (PASI 75).

Papp's group found that after 12 weeks of treatment, 47 percent of patients who received the highest dose of ISA247 achieved PASI 75. Patients receiving lower doses achieved a 25 percent or a 16 percent improvement in their PASI score. Among patients in the placebo group, only four of 115 achieved PASI 75, the researchers reported.

"ISA247 is a reasonable oral medication for the treatment of psoriasis," Papp said. "It is reasonable because of reasonable efficacy, high tolerability and minimal metabolic effects."

In addition, because the effect of the drug correlates with its dose, it "can be titrated to suit patients response and tolerance without undue risk of adverse effects," Papp said.

One expert thinks the result of this trial needs to be duplicated in longer-term studies, and it needs to put in a head-to-head comparison with other psoriasis drugs.

"ISA247 may offer advantages compared with ciclosporin," said Dr. Luigi Naldi, from the Unit of Dermatology and GISED Study Centre at Ospedali Riuniti di Bergamo, Italy, and author of an accompanying editorial. "However, its efficacy and safety profile needs to be further evaluated in the context of longer-term comparative studies."

Naldi noted that these trials need to be done in real-life situations. In addition, the trial done by Papp is too short to really tell whether or not the drug is safe, since most patients taking the drug would have to use it for a long time to control their psoriasis, he said.

"The risk of chronic kidney toxicity induced by calcineurin inhibitors increases with treatment duration and cannot be reliably predicted with short-term data," Naldi said." An obvious comparator in the ISA247 trial would have been ciclosporin. Without such an internal comparison, the claim that ISA247 is safer than ciclosporin should be viewed cautiously, because it is based on external comparisons," he said.

More information

For more on psoriasis, visit the U.S. National Library of Medicine.

SOURCES: Kim Papp, M.D., Ph.D., Probity Medical Research, Waterloo, Ontario, Canada; Luigi Naldi, M.D., Unit of Dermatology and GISED Study Centre, Ospedali Riuniti di Bergamo, Italy; April 19, 2008, The Lancet

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