Two Experimental Drugs Could Improve Psoriasis
WEDNESDAY, March 28 (HealthDay News) -- A new type of treatment
may be on the horizon for people with moderate to severe cases of
the chronic skin condition known as psoriasis.
Two studies, published in the March 29 issue of the
New England Journal of Medicine, found that drugs that interfere with an immune system molecule called interleukin-17 (IL-17) led to significant improvements in skin lesions for more than 75 percent of patients over a 12-week period.
Both studies were phase 2 clinical trials, which researchers
conduct to determine the safest and most effective dose. The drugs
next have to be tested in more people over a longer period of
Although the effectiveness of IL-17 inhibitors seems similar to
that of other biologic drugs for psoriasis that are already on the
market, such as Enbrel and Stelara, these drugs could offer
patients more and possibly safer options, said Dr. Craig Leonardi,
a clinical professor of dermatology at Saint Louis University who
was involved in both IL-17 studies.
"Not every drug works in every patient, but there is also a phenomenon with these biologic drugs, some call it 'biologic fatigue,' where these drugs seem to lose efficacy over time," Leonardi said. IL-17 inhibitors could be new options for these patients.
Psoriasis is an autoimmune disease that affects up to 7.5
million people in the United States, according to the National
Psoriasis Foundation. People with moderate psoriasis have red,
inflamed lesions covering between 3 percent and 10 percent of their
body. For these patients, doctors generally prescribe biologics,
including TNF inhibitors like Enbrel, Humira, Remicade or
The current studies tested a drug that directly blocks IL-17 and
a drug that blocks an IL-17 receptor, which IL-17 has to bind to in
order to exert its effects on the immune system. The studies
divided patients into several groups receiving different doses of
either drug or an inactive placebo, and injected patients every
one, two or four weeks, depending on the drug and dose.
Both studies were funded by pharmaceutical companies. Eli Lilly
supported the study of the direct IL-17 inhibitor. Amgen supported
the trial of the inhibitor of the IL-17 receptor.
Researchers found that the drug that directly blocks IL-17,
called ixekizumab, improved psoriasis plaques by 75 percent for
about 77 percent of patients at the lowest effective dose and for
82 percent patients at the highest dose after 12 weeks. Between
about 38 percent and 39 percent of patients had a 100 percent
improvement in lesions in that time period.
With the other drug, brodalumab, researchers saw an improvement
of at least 75 percent after 12 weeks in 77 and 82 percent of
patients at the middle doses. On average, patients' lesions
improved by 45 percent, 76 percent and 86 percent at the different
The two drugs were similar in their effectiveness, according to
Leonardi, who was the lead author on the ixekizumab trial and a
co-author on the brodalumab trial.
The most common side effects of the drugs were infections and
inflammation in the upper respiratory tract and injection site
The researchers did not see any serious side effects with
ixekizumab. Serious side effects were rare in the brodalumab trial,
but they included a drop in the number of immune cells, severe
kidney pain and ectopic pregnancy.
Leonardi said that the lack of side effects was impressive.
"These two IL-17 drugs were some of the quietest trials I've ever
participated in." However, "the qualifier is we've got to go
through phase 3," he added.
So far, the IL-17 inhibitors have also not been associated with
an increased risk of heart attack or stroke. This is notable,
Leonardi said, because there is some concern after previous
research suggesting that Stelara could increase the risk of these
diseases. (Leonardi was also involved in studies of Stelara.)
In theory, inhibiting IL-17 could be a safer treatment option
than other biologics because IL-17 is considered to be the molecule
that is largely responsible for psoriasis. In fact, researchers
learned about the importance of IL-17 after realizing that one of
the interleukins that Stelara suppresses actually leads to the
inhibition of IL-17, Leonardi explained.
"If you are more specific at targeting what's abnormal with psoriasis, you could lead to a lower risk of side effects," said Dr. Lawrence Green, a dermatologist in the Washington, D.C. area who was not involved in the latest research.
Green has received research and speaking fees from Amgen as well
as other companies that make psoriasis drugs, including
However, IL-17 inhibitors will suppress the immune system, just
like other psoriasis drugs, so there is always the possibility of
an increased risk of infection, Green said.
"The most important reason it is nice to have different medications out there is that some patients don't respond to TNF inhibitors or Stelara," he added.
"For those people already doing well on TNF inhibitors, there's no reason to change, but it's fantastic for those people who can't take them anymore. Now you have an alternative and you can feel better about controlling the condition for the rest of your life," Green explained.
If the IL-17 inhibitors are effective and safe in patients in
phase 3 clinical trials, these drugs could be available for
patients in two to three years, Leonardi said.
Researchers are also studying IL-17 inhibitors as possible
treatments for rheumatoid arthritis.
To learn more about psoriasis, visit the
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