| In
2000, according to IMS HEALTH's MIDAS
system, the world psoriasis therapy market (class
D5) was worth $500.2 million, up 10.4% from 1999.
80.1% of sales were of topical products (D5A) and
19.9% of sales were made up by oral products (D5B).
Over 1996-1999, the proportion of the market taken
by oral products has been slowly increasing (they
represented only 16.9% of sales in 1996).
| Psoriasis
therapy world market: leading companies
12 months to December 2000
| Company
|
Main
Products |
Market Share % |
| Bristol-Myers
Squibb |
Daivonex
(calcipotriol)/Sebutone/Balnetar |
22.7
|
| Roche
|
Neotigason
(acetretin)/Tigason (etretinate) |
15.7
|
| Leo
|
Daivonex
(calcipotriol) |
13.9
|
| Allergan
|
Zorac
(tazarotene) |
6.1
|
| Teijin
|
Bonalfa
(tacalcitol) |
5.3
|
| Fujisawa
|
Prograf
(tacrolimus)/Dovonex (calcipotriol) |
4.3
|
| Stiefel
Labs |
Polytar/Tersa-Tar/Tarmed
(coal tar) |
3.5
|
| Boots
|
Fumaderm
(monethylfumarate)/Curatoderm (talcalcitol)
|
3.4
|
| Schering
AG |
Psorcutan
(calcipotriol) |
3.2
|
| American
Home Products |
Denorex
(coal tar solution) |
1.5 |
|
Source:
MIDAS
The
market is currently dominated by Leo's calcipotriol,
which has been licensed out to Bristol-Myers Squibb,
Fujisawa and Schering AG. Also important are Roche
and Allergan with the retinoids Tigason/Neotigason
and Zorac. Another major vitamin D derivative
is Teijin's Bonalfa (tacalcitol), which is
marketed by licensee Boots as Curatoderm. Stiefel
is the leader in the coal tar product sector.
No cure, many treatments unsatisfactory
There is currently no cure for psoriasis. Mild-to-moderate
psoriasis can be treated by various topical products,
such as steroids, coal tar or vitamin A and D derivatives.
One vitamin D derivative that has made a major impact
on the market is Leo's Daivonex/Dovonex (calcipotriol),
first launched in 1991. In 2000, Galderma launched
a new topical vitamin D derivative, Silkis (calcitriol).
In moderate-to-severe cases, phototherapy may be recommended,
and in very severe cases, systemic medications such
as cyclosporin, methotrexate and oral retinoids may
be used.
Unfortunately, many of these treatments have problems.
Some treatments for severe psoriasis have serious
side-effects:
-
Coal tar is messy and can make the skin sensitive
to ultraviolet light
-
Use of steroids may cause thinning of the skin
-
Topical vitamin A and D derivatives may cause skin
irritation
-
Oral retinoids can cause birth defects
New therapies in development
Despite the number of products on the market, there
is still a significant need for long-lasting and safe
treatments for psoriasis. The meeting of the American
Academy of Dermatology in Washington DC, March 2001,
saw a number of biotech companies reporting on new
recombinant treatments in development for psoriasis.
The most advanced are:
- Xanelim
(efalizumab), an anti-CD11a monoclonal antibody,
in development with Genentech and Xoma
-
Biogen's fusion protein Amevive (alefacept)
Both
are now in Phase III. Based on Phase II data presented
at the AAD meeting, Xanelim administered subcutaneously
is well-tolerated, effective and reasonably safe.
However, psoriasis recurred in a matter of weeks once
treatment was interrupted, so chronic administration
is required.
Amevive showed good results and an excellent duration
of response when given intravenously. But, there were
concerns about toxicity and the fact that clinical
benefit was achieved at the expense of a significant
decline in memory T cells. The effects on T cells
were only slowly reversible. This is potentially dangerous,
as T cell depletion could lead to a risk of infection.
Earlier stage products
At the AAD meeting, IDEC presented encouraging results
from a multiple-dose Phase I/II trial of IDEC-114,
an anti-CD80 antibody. The trial involved 35 patients
with moderate-to-severe psoriasis, with 57% of the
patients rated as having a good response to the treatment.
In addition, the effects of IDEC-114 lasted beyond
the final day of the trial. Side-effects were mild
and included colds, chills and tiredness. IDEC began
a Phase II, multiple-dose study with IDEC-114 in January
2001.
ABX-IL8 is an anti-interleukin-8 antibody from
Abgenix in Phase IIb studies. Results from a Phase
IIa trial in 94 patients with moderate-to-severe psoriasis
were reported. Statistically significant improvements
in PASI (Psoriasis Area and Severity Index) score
were reported for the 3mg/kg patient group, although
patients receiving 6mg/kg did not experience statistically
significant decreases in their PASI scores.
Johnson & Johnson subsidiary Centocor's anti-TNF antibody
Remicade (infliximab), for Crohn's disease
and rheumatoid arthritis, may also have potential
in psoriasis. Results from a 33-patient Phase II study
found that 80% of patients achieved a good, excellent
or clear rating, as opposed to 18% of those on placebo.
Remicade rapidly cleared psoriasis in a high proportion
of patients after three injections, and J&J is reported
to be planning additional trials in psoriasis.
Ligand presented data from a Phase II trial with its
fusion protein Ontak (denileukin difitox),
but there were concerns about the level of adverse
reactions, which included fever, pain and dizziness.
Fujisawa's Protopic, a topical version of its
immunomodulator Prograf (tacrolimus), which
is used to treat eczema, also has potential for psoriasis,
as does the Novartis eczema drug Elidel (pimecrolimus),
which has been filed with the FDA. Meanwhile, Immunex's
RA treatment, Enbrel (etanercept) is also in
clinical trials for psoriasis, and should be filed
for psoriatic arthritis in mid-2001. |
