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Biologic
Drugs for the Treatment of Psoriasis 
For
specific drug information please click on relevant drug: -
Adalimumab
- Humira
Etanercept - Enbrel
Infliximab - Remicade
Ustekinumab
- Stelara
Efalizumab - Raptiva - this
product no longer has a license
What are biologics?
Most medications are created by combining chemicals. In contrast ‘biologic
drugs’ are made from living human or animal proteins. The medications
made from these proteins are specifically designed to act in certain
ways in the body to correct something going wrong that leads to disease.
Biologics
are not new medications- they have been in use for more than 100 years.
Vaccines and insulin are considered biologics because they are derived
from living sources. It is only recently however that biologics that
are specifically targeted toward psoriasis and psoriatic arthritis have
begun to emerge as potentially promising new treatment options.
Why
are they different?
Biologics are different from other medications for psoriasis and psoriatic
arthritis because they are designed to block both diseases early in
their development - in the immune system.
Psoriasis
and psoriatic arthritis begin in the immune system when certain immune
system cells are triggered and become overactive. These overactive cells
set off a series of events in the body, eventually causing psoriasis
to develop on the skin and arthritis symptoms to develop in the joints.
Biologics work for psoriasis and psoriatic arthritis by blocking the
action of certain immune cells that play a role in the diseases. In
some cases biologics reduce the number of these cells in the skin and
blood . In other cases they block the activation of the immune cells
or block the psoriasis causing chemicals released by them.
Almost
all treatments that work for psoriasis and psoriatic arthritis impact
or target the immune system in some way. This is true for Ultra violet
treatment and systemic medications such as methotrexate and ciclosporin
The difference is that their impact on the immune system and body is
broad, including the risk of potentially serious side effects on other
organs. Biologics are more targeted and should spare the body these
broad side effects and they have the potential to be a safer option.
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How
do they work?
Biologics are designed to treat psoriasis and psoriatic arthritis by
targeting overactive cells in the body. Some biologics target a type
of immune cell called T cells while others target the chemical messengers
released by activated T cells.
T cells normally recognise bacteria and viruses and coordinate the immune
response to eliminate these foreign invaders.
In psoriasis
certain T cells are mistakenly activated and migrate to the skin. Once
in the skin they begin to act as if they are fighting an infection or
healing a wound and this sets off a chain of events that leads to the
rapid growth of skin cells. In psoriasis skin cells grow much faster
than normal and this over production causes cells to pile up at the
skins surface. Certain biologic medications treat the psoriasis by preventing
the activation and/or migration of T cells, by reducing the number of
psoriasis involved T cells in the body, or both.
TNF -alpha
(tumour necrosis factor alpha) also helps fight infections and it communicates
messages between cells. In people with psoriasis and psoriatic arthritis
TNF alpha is produced in excess amounts by activated T cells. The messages
communicated by TNF alpha lead to the rapid growth of skin cells found
in psoriasis or to the joint pain and stiffness associated with psoriatic
arthritis.
Several
biologic medications were developed to treat rheumatoid arthritis and
other diseases by binding to TNF alpha and preventing it from communicating
with cells. It has been found that these TNF alpha agents are also effective
to different degrees in treating psoriatic arthritis and psoriasis.
In addition to agents
that target TNF-alpha, there are biologic agents that target interleukin-12
(IL-12) and interleukin-23 (IL-23). IL-12 and IL-23 help to coordinate
cells of the immune system to fight infections. However, levels of IL-12
and IL-23 have been found to be higher than expected in patients with
psoriasis, and biologic agents that block the activity of IL-12 and
Il-23 have been shown to be effective treatments for patients with moderate
to severe psoriasis.
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Who
can take biologics?
The biologic medications have been investigated by the National Institute
for Health and Clinical Evidence (NICE) who have issued guidelines on
when they can be prescribed. NICE have issued guidelines for five of
the biologics used to treat psoriasis, Etanercept (Enbrel), Efalizumab
(Raptiva), Infliximab (Remicade) and Adalimumab (Humira) and Ustekinumab
(Stelara). However, since issuing the guidance, Raptiva has had its
marketing authorisation suspended and so will not be prescribed.
NICE recommends that Enbrel, Humira and Ustekinumab can be prescribed
for people with severe psoriasis who have not responded to other systemic
treatments such as PUVA, Methotrexate, Ciclosporin and Acitretin. Or
if these treatments cause a reaction which means the person should not
take them, or if the person has another condition or medication which
means that they should not take the other systemic treatments. Should
the psoriasis not show a measured response after 12 weeks (in the case
of Enbrel and Humira) NICE recommends that the treatment be stopped.
Should the psoriasis not show a measured response (in the case of Stelara)
after 16 weeks of starting treatment, NICE recommends that the treatment
be stopped. Remicade can be offered for the treatment of very severe
plaque psoriasis if the psoriasis has not responded to other systemic
treatments such as PUVA, Methotrexate or Ciclosporin. If the psoriasis
has not shown a measured response after 10 weeks then treatment should
be stopped.
NICE have issued guidelines for three of the biologics used to treat
severe Psoriatic Arthritis, Enbrel, Remicade and Humira. NICE recommends
that Enbrel and Humira can be prescribed for people with severe psoriatic
arthritis when the person has three or more tender joints and three
or more swollen joints and at least two other Disease Modifying Anti-Rheumatic
Drugs (DMARDs) given on their own, or together, have not worked. If
the psoriatic arthritis has not shown a measured response at 12 weeks,
NICE recommends that the treatment be stopped. Remicade can then be
offered to people with psoriatic arthritis, or if the person has a condition
or takes another medicine that means they should not take Enbrel or
Humira, also if the person has major difficulty injecting themselves.
As with Enbrel and Humira, if the person’s psoriatic arthritis
has not shown a measured response at 12 weeks, their treatment with
Remicade should be stopped.
Key
features of the biologic drugs
• Taken by injection ( either in a surgery or at home depending
on the specific medication)
• Treatment schedule and frequency vary
• Will improve psoriasis and psoriatic arthritis for some people
but not all
• Short term side effects are generally minor although an allergic
reaction to the injection can occur
• Long term safety is still being evaluated.
• They are expensive - between £8000 and £10,000 per
annum.
• They must be taken continuously to maintain improvement.
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