ARTICLE
Auteur(s) : Kristian Reich1, Frank O
Nestle2, Ying Wu3, Mohan Bala3,
Debra Eisenberg3, Cynthia Guzzo3, Shu
Li3, Lisa T Dooley3, Christopher EM
Griffiths4
1Department of Dermatology, Georg-August University;
Von-SieboldStrasse 3, 37075, Göttingen, Germany
2St John’s Institute of Dermatology, King’s College
London School of Medicine at Guy’s, King’s College & St Thomas’
Hospitals, Floor 8 Guy’s Tower, Guy’s Hospital, London SE1 9RT,
United Kingdom
3Centocor, Inc., 200 Great Valley Parkway, Malvern, PA
19355, United States
4The Dermatology Centre, The University of Manchester,
Hope Hospital, Stott Lane, Salford, Manchester, M6 8HD, United
Kingdom
accepté le 18 Avril 2007
Psoriasis affects approximately 2% of the population. The affected
individuals, many of who are of working age, experience severe
physical discomfort and impaired quality of life. The psychological
impact of psoriasis on patient quality of life has been well
documented [1, 2]. Patients suffer from a variety of psychosocial
burdens, including stigmatization, stress, depression, and other
psychosocial co-morbidities [3]. The severity of depression may be
significant, as highlighted by a recent study reporting that over
5% of patients had active suicidal ideation [4].As further evidence
of the profound emotional and social impact of psoriasis, the
perception of general health and social functioning was shown to be
affected to a greater degree in individuals with moderate-to-severe
psoriasis than in those with certain other chronic diseases,
including hemophilia, hypertension, back pain, and arthritis [5].
In a survey conducted by the National Psoriasis Foundation, 79% of
6,194 patients with severe psoriasis reported that psoriasis had a
negative impact on their lives [6]. Taken together, these findings
underscore the significant psychosocial burden associated with
psoriasis.The physical manifestations and psychological effects of
psoriasis can result in missed days of work and decreased
productivity at work. In a survey in the United Kingdom among
patients with severe psoriasis, Finlay et al. found that 59.3% of
those who were employed had missed an average of 26 workdays during
the preceding year due to their psoriasis. Among patients who were
not working, 33.9% attributed not working to their psoriasis [7].
An analysis of a nationwide survey in the United States (US), which
included 1,127 psoriasis patients, found that psoriasis had a
significant negative impact on work and productivity. Compared with
matched controls, psoriasis patients were more likely to report
missing more than one day of work, having impaired productivity at
work, and having more impairment of activities other than work, all
due to health reasons [8]. Other studies have also demonstrated a
reduction in work productivity and social functioning in patients
with mild, moderate, or severe psoriasis [9, 10].The clinical
effectiveness of the tumor necrosis factor alpha (TNF-α) inhibitor,
infliximab, in psoriasis has now been demonstrated [11-13].
Infliximab given at weeks 0, 2, and 6, and every 8 weeks thereafter
significantly and rapidly improved signs and symptoms of psoriasis,
as measured by the Psoriasis Area and Severity Index (PASI) [14,
15], and patient health-related quality of life (HRQoL) [16], as
assessed by the disease-specific Dermatology Life Quality Index
(DLQI) [17] and the generic 36-item Short Form Health Survey
(SF-36) [18]. Work productivity in patients with psoriasis,
however, has not been studied in a large, placebo-controlled study.
We thus analyzed data from a large, randomised, double-blind,
placebo-controlled, Phase III study (EXPRESS) to investigate the
effects of infliximab therapy on patient productivity. As reported
previously [14], data from EXPRESS showed that PASI 75 and PASI 90
responses (i.e., ≥ 75% or ≥90% improvement in PASI scores from
baseline, respectively) at week 10 were achieved by significantly
greater proportions of patients receiving infliximab compared with
those receiving placebo (80.4% vs. 2.6% for PASI 75 and 57.1% vs.
1.3% for PASI 90; both p < 0.001). DLQI scores, physical
component summary (PCS) scores, and mental component summary (MCS)
scores (mean ± SD changes from baseline) also improved
significantly at week 10 for patients receiving infliximab compared
with placebo (10.3 ± 7.1 vs. 0.4 ± 5.7 for DLQI scores; 5.0 ± 8.3
vs. – 0.4 ± 7.7 for PCS; 6.3 ± 11.0 vs. – 0.8 ± 9.7 for
MCS; p < 0.001 for all comparisons) [16]. Demonstrating improved
work productivity in patients with psoriasis would be of value,
particularly with regard to the impact of lost productivity on the
indirect costs of this chronic disease [19].
Materials and methods
Study design and patients
Study design and eligibility criteria for the Phase III,
multicentre, double-blind, placebo-controlled EXPRESS trial have
been described elsewhere [14]. The trial was conducted at 32
centres (23 in Europe and 9 in Canada), with the approval of the
Institutional Review Boards or Institutional Ethics Committees of
all sites. All patients signed an informed consent form before
undergoing any trial procedures. Briefly, the study enrolled 378
adult patients who had moderate-to-severe psoriasis and were
candidates for phototherapy or systemic therapy. All patients were
required to have a PASI score of at least 12 and at least 10%
involvement of body surface area (BSA) with psoriasis. Patients
were excluded if they had been treated previously with any TNF-α
blocking agents or had a history or risk of serious infection,
lymphoproliferative disease, or active or latent tuberculosis.
Eligible patients were randomised 4:1 at baseline to receive
infliximab or placebo. The infliximab group received intravenous
infusions of infliximab 5 mg/kg at weeks 0, 2, and 6, and then
every 8 weeks thereafter through week 46. The placebo group
received placebo infusions at weeks 0, 2, 6, 14, and 22, and then
crossed over in a double-blind fashion to receive infliximab 5
mg/kg at weeks 24, 26, and 30 followed by 5 mg/kg every 8 weeks
through week 46. In the infliximab group, placebo infusions were
given at weeks 24 and 26 to maintain the blind. PASI was used to
assess clinical response [20].
Productivity assessment
Productivity was measured based on several features, using a visual
analog scale (VAS) as well as key productivity-related questions
from the SF-36 and DLQI. Patients were asked to assess how
psoriasis affected their productivity at work, school, or home. The
VAS ranges from 0 cm, indicating that productivity was very
much impacted by their disease, to 10 cm, indicating that
their disease had no impact at all on productivity. The VAS has
been used to assess productivity in studies of infliximab in other
diseases, including ankylosing spondylitis and psoriatic arthritis
[21, 22].
Additionally, the impact of physical health and emotional
problems on work or daily activities was assessed using the
role-physical and role-emotional domains of the SF-36
questionnaire. The SF-36 is widely used to assess patient HRQoL in
several disease states. The SF-36 consists of 8 multi-item domains:
physical functioning, role-physical, bodily pain, mental health,
role-emotional, social functioning, vitality, and general health.
Two summary components of the SF-36, the PCS and the MCS, are
derived by aggregating the individual scale scores. The mean
(± SD) for the PCS and the MCS scores in the general US
population is 50 (± 10) [18]; scores in the European
population are similar [23]. Higher scores on the SF-36 summary or
domain scores represent better HRQoL.
The role-physical domain of the SF-36 assesses whether physical
health in the past 4 weeks had impacted work and other regular
daily activities, such as reducing the amount of time the patient
spent at work or on other activities, accomplishing less than
he/she would like, being limited in the kind of work or other
activities, or having difficulty performing their work or other
activities. The role-emotional domain assesses whether emotional
problems, such as feeling depressed or anxious, in the past 4 weeks
had an impact on these aspects of work or other activities.
The DLQI consists of 10 questions that assess the impact of skin
disease on six different domains, with possible responses for each
question ranging from 0 (“not at all”) to 3 (“very much”). Summing
the scores for all questions produces a total DLQI score that
ranges from 0 to 30, with lower scores indicating better HRQoL. A
DLQI score above “10” indicates a very large effect on HRQoL [24].
Two questions of the DLQI assess the impact of the condition of the
skin on working and studying. One question assesses whether the
skin condition prevented the patient from working or studying
(yes/no). If the answer is “no”, a follow-up question assesses how
much the skin condition has been a problem at work or studying (a
lot/a little/not at all). The responses to these questions were
analyzed to further evaluate the impact of infliximab therapy on
the patients’ ability to work or study.
Productivity VAS, SF-36, and DLQI scores were evaluated at
baseline and at weeks 10, 24, and 50.
Statistical analysis
The changes from baseline in productivity VAS and SF-36 scores at
week 10 and week 24 were compared between the infliximab and
placebo groups using a 2-sample t-test on the van der Waerden
normal scores. Note that for percent change from baseline in
productivity, median (rather than mean) values were deemed the most
appropriate summary statistic because the mean values were skewed
by large percent changes observed in patients with low productivity
scores at baseline. No data were imputed. All analyses were
conducted based on available data. The bias resulting from this
should be minimal, since few patients had missing data. Changes of
a half of a standard deviation were considered clinically
significant, where applicable [25]. Spearman’s correlation was used
to assess the correlations between productivity VAS and clinical
parameters in all patients. All statistical tests were two-sided at
an alpha level of 0.05. Statistical analyses were performed using
the SAS (Version 8, SAS Institute, Cary, NC).
Results
Baseline characteristics
Baseline clinical and demographic patient characteristics for the
EXPRESS study have been reported elsewhere in detail [14]. Briefly,
most study participants were male (70.9%), with a mean age of 42.8
years, mean percentage BSA involvement of 34.0%, and mean PASI
score of 22.9 at baseline (table 1). All
demographic and disease parameters were comparable between
treatment groups. At baseline, the mean DLQI score for the study
population was elevated at 12.5, and the mean SF-36 PCS and MCS
scores were decreased at 45.6 and 45.7, respectively.
The average baseline SF-36 role-physical domain score was low,
compared with the US average (65.8 versus 81.0) [26]; this was also
true for the role-emotional domain score (72.1 versus 81.0).
Baseline productivity data indicated impaired productivity (mean
VAS: 5.9 cm), indicating the average self-reported
productivity was about 40% below the maximal level of 10 cm
(table 1).
Table 1 Baseline characteristics of psoriasis patients
in the EXPRESS study
|
Characteristics
|
Placebo (n = 77)
|
Infliximab 5 mg/kg (n = 301)
|
Total (n = 378)
|
|
Age (yrs)
|
|
|
|
|
Mean ± SD
|
43.8 ± 12.6
|
42.6 ± 11.7
|
42.8 ± 11.9
|
|
Sex, n (%)
|
|
|
|
|
Male
|
61 (79.2)
|
207 (68.8)
|
268 (70.9)
|
|
Female
|
16 (20.8)
|
94 (31.2)
|
110 (29.1)
|
|
Race, n (%)
|
|
|
|
|
Caucasian
|
74 (96.1)
|
295 (98.0)
|
369 (97.6)
|
|
Black
|
1 (1.3)
|
1 (0.3)
|
2 (0.5)
|
|
Asian
|
2 (2.6)
|
2 (0.7)
|
4 (1.1)
|
|
Other
|
0 (0.0)
|
3 (1.0)
|
3 (0.8)
|
|
BSA (%)
|
|
|
|
|
Mean ± SD
|
33.5 ± 17.5
|
34.1 ± 19.0
|
34.0 ± 18.7
|
|
PASI score (0-72)
|
|
|
|
|
Mean ± SD
|
22.8 ± 8.7
|
22.9 ± 9.3
|
22.9 ± 9.2
|
|
DLQI score (0-30)
|
|
|
|
|
Mean ± SD
|
11.8 ± 7.5
|
12.7 ± 7.0
|
12.5 ± 7.1
|
|
SF-36 PCS (0-100)
|
|
|
|
|
Mean ± SD
|
47.2 ± 9.2
|
45.2 ± 11.1
|
45.6 ± 10.8
|
|
SF-36 MCS (0-100)
|
|
|
|
|
Mean ± SD
|
45.4 ± 12.5
|
45.8 ± 11.7
|
45.7 ± 11.9
|
|
SF-36 RP scores
|
|
|
|
|
Mean ± SD
|
69.8 ± 37.7
|
64.8 ± 41.1
|
65.8 ± 40.4
|
|
SF-36 RE scores
|
|
|
|
|
Mean ± SD
|
71.9 ± 38.6
|
72.1 ± 38.7
|
72.1 ± 38.7
|
|
Productivity VAS (0-10 cm)
|
|
|
|
|
Mean ± SD
|
6.3 ± 3.2
|
5.8 ± 3.4
|
5.9 ± 3.3
|
Patient disposition
Through week 24, of the 77 patients in the placebo group and 301
patients in the infliximab group, respectively, 3 (3.9%) and 20
(6.6%) discontinued the study agent due to adverse events and 5
(6.5%) and 2 (0.7%) due to unsatisfactory therapeutic effects.
Through week 50, the study agent was discontinued in 8 (10.4%) and
34 (11.3%) patients due to adverse events and in 7 (9.1%) and 14
(4.7%) patients due to unsatisfactory therapeutic effects in the
placebo crossover and infliximab groups, respectively.
Productivity
Productivity, as measured by the VAS, and the role-physical and the
role-emotional domain scores of the SF-36 improved significantly
from baseline at weeks 10 and 24 (table
2). At week 10, there was a statistically significant
difference in mean change in VAS productivity when comparing the
infliximab (2.7 cm increase) and placebo groups (0.1 cm
decrease; p < 0.001); this difference was sustained through week
24 (a mean increase of 2.5 cm for infliximab compared with a
mean decrease of 0.2 cm for placebo; p < 0.001).
The median percent increase in VAS productivity at week 10 was
22.5% for the infliximab group, as compared with a median percent
decrease of 1.1% for the placebo group (p < 0.001). At week 24,
the median percent increase was 23.6% for the infliximab group
compared with no change for the placebo group (p < 0.001, figure 1).
Similar trends were observed in the SF-36 role-physical and
role-emotional domain scores (table 2).
Mean role-physical scores in the infliximab and placebo groups,
respectively, were 64.8 and 69.8 at baseline, 85.8 and 64.6 at week
10, 83.7 and 67.2 at week 24, and 78.9 and 74.1 at week 50; mean
role-emotional scores in the respective groups were 72.1 and 71.9
at baseline, 90.6 and 69.7 at week 10, 89.6 and 70.1 at week 24,
and 83.3 and 77.1 at week 50. Detailed analysis of the
role-physical and role-emotional domains showed a substantial
impact on work or daily activities with infliximab treatment (table 3). The proportion of patients in the
infliximab group who stated that physical health had an impact on
work or daily activities (i.e., responded “yes” to at least one
question in the role-physical scale) decreased from 49.7% at
baseline to 20.6% at week 10. Similarly, the proportion of patients
who stated that emotional problems affected work or daily
activities decreased from 39.3% to 14.8% in the infliximab group
through week 10, while modest changes were observed in the placebo
group during this period.
At week 50, improvements in both productivity and role-emotional
and role-physical scores were sustained with infliximab maintenance
therapy (table 2). These changes were
consistent regardless of gender. Improvement in these parameters
for placebo patients who had crossed over to infliximab at week 24
approached that seen for those receiving infliximab maintenance
therapy from baseline.
Based on responses to the DLQI questionnaire at baseline, 12.1%
of patients in the infliximab group (n = 36) and 9.1% of those in
the placebo group (n = 7) reported that their skin condition
prevented them from working or studying at baseline. The proportion
decreased to 1.4% (n = 4) at week 10 in the infliximab group, while
a small increase (to 11.6%; n = 8) was observed in the placebo
group. Among patients who stated that their skin condition
prevented them from working at baseline, 84.9% of patients in the
infliximab group (n = 28) stated that their skin condition no
longer prevented them from working at week 10, compared with 42.9%
of those in the placebo group (n = 3; p < 0.01).
Among patients who had stated that their skin condition did not
prevent them from working or studying at baseline, 60.2% of those
in the infliximab group (n = 133) and 47.3% of those in the placebo
group (n = 26) still reported that their skin condition was a
problem while working or studying. Among the subset of patients who
had stated that their skin condition had been a problem while
working or studying at baseline, 87.7% of those in the infliximab
group (n = 107) stated that their skin condition was no longer a
problem while working or studying at week 10, compared with 17.7%
of those in the placebo group (n = 3; p < 0.001).
Table 2 Mean (± SD) improvement from baseline in
productivity and SF-36 role-physical and role-emotional domain
scores through week 50 by visit; randomised psoriasis patients in
the EXPRESS study
|
Placebo-Infliximab Crossover (n = 77)
|
Infliximab 5 mg/kg (n = 301)
|
p-value
|
|
Productivity VASa
|
|
Week 10
|
– 0.1 ± 2.9
|
2.7 ± 3.5
|
< 0.001
|
|
Week 24
|
– 0.2 ± 3.2
|
2.5 ± 3.5
|
< 0.001
|
|
Week 50
|
1.9 ± 3.6
|
2.0 ± 3.4
|
NA
|
|
SF-36 RP scoresa
|
|
Week 10
|
– 5.2 ± 35.0
|
20.6 ± 37.8
|
< 0.001
|
|
Week 24
|
– 2.6 ± 35.5
|
18.5 ± 39.8
|
< 0.001
|
|
Week 50
|
4.3 ± 36.7
|
13.5 ± 39.6
|
NA
|
|
SF-36 RE scoresa
|
|
Week 10
|
– 2.2 ± 28.3
|
18.2 ± 39.2
|
< 0.001
|
|
Week 24
|
– 1.7 ± 33.3
|
16.5 ± 38.0
|
< 0.001
|
|
Week 50
|
5.2 ± 41.9
|
10.8 ± 36.6
|
NA
|
aAt weeks 0, 10, 24, and 50, respectively,
productivity VAS scores were available for 374, 366, 352, and 352
patients and RE and RP scores were available for 375, 369, 353 and
356 patients.
Table 3 Detailed SF-36 role-physical and role-emotional
response at week 10a
|
Domain and questions
|
Placebo
|
Infliximab
|
|
Baseline
|
Week 10
|
Baseline
|
Week 10
|
|
Role-physical:
|
|
|
|
|
|
Impact of physical health on work or daily activities
|
46.8
|
45.1
|
49.7
|
20.6
|
|
Cut down time spent on work or other activities
|
20.8
|
22.5
|
29.2
|
11.3
|
|
Accomplished less than one would like
|
36.4
|
35.2
|
41.6
|
15.5
|
|
Limited in the kind of work or other activities
|
31.2
|
33.8
|
32.9
|
12.7
|
|
Had difficulty performing work or other activities
|
32.5
|
35.2
|
37.3
|
14.8
|
|
Role-emotional:
|
|
|
|
|
|
Impact of emotional problems on work or daily activities
|
40.3
|
39.4
|
39.3
|
14.8
|
|
Cut down time spent on work or other activities
|
23.4
|
26.8
|
23.5
|
8.6
|
|
Accomplished less than one would like
|
31.2
|
32.4
|
34.2
|
12.0
|
|
Didn’t do work or other activities as carefully as usual
|
29.9
|
21.1
|
25.8
|
7.2
|
aValues for specific questions are the
percentages of patients who answered “yes”. Values for impact of
physical health or emotional problems on work or daily activities
are the percentages of patients who answered “yes” to at least one
of the questions associated with that domain.
Correlation between VAS and clinical parameters
Significant correlations were observed in the change from baseline
to week 10 between productivity VAS and both PASI (r = – 0.33;
p < 0.001) and DLQI (r = –0.58; p < 0.001) scores.
Figure 2 shows
the decline in productivity with increasing PASI scores in all
patients.
Discussion
Using data from patients with moderate-to-severe psoriasis from the
large, Phase III EXPRESS study, we show that infliximab therapy is
associated with significant improvement in patient productivity as
measured by the 10-cm VAS and selected SF-36 domain scores and DLQI
responses. The strengths of our study include the large sample
size, the placebo-controlled design, and the comprehensive
measurement of productivity by analysis of key productivity-related
questions as well as productivity VAS data.
Although several biologics have been approved for treating
psoriasis, this is the first study to demonstrate an association
between reducing the signs and symptoms of moderate-to-severe
psoriasis and improving patient productivity. Data generated from
this study may have economic implications as we further investigate
the financial burden of psoriasis. Few cost-of-illness studies have
been conducted for psoriasis. Moreover, the cost estimates derived
from published studies vary from approximately $1 billion to more
than $4 billion per annum in the US. Several years ago, Krueger et
al. estimated the combined cost of hospitalization and outpatient
therapy to be approximately $1.6 billion [27]. A more recent
cost-of-illness analysis of psoriasis in the US found that the
direct medical cost of psoriasis was much lower, about $650 million
[28]. A recently reported cost-of-illness study in Germany found
that the mean total cost was euro 6,709 per patient per year; these
patients had a mean PASI score of 18.2. These costs were higher in
“high-need” patients (euro 8,831; PASI score of 22.2) [19]. The
indirect costs of psoriasis, including the economic impact of work
days lost and reduced productivity while at work, however, have not
been well studied and can be substantial. Thus, the total cost of
psoriasis to society could be much higher. In this study, we have
confirmed the negative impact of psoriasis on patients’ work and
productivity and have demonstrated that infliximab therapy
significantly improved self-reported productivity among patients
with moderate-to-severe psoriasis. Further studies are needed to
evaluate the economic value of such improvement.
The productivity VAS used in this study has already been used in
two infliximab studies in other indications. In ASSERT, a Phase
III, randomised, placebo-controlled trial assessing the efficacy
and safety of infliximab in patients with ankylosing spondylitis,
van der Heijde et al. found that the productivity VAS increased
significantly compared with placebo in patients who received
infliximab 5 mg/kg at weeks 0, 2, 6, and every 6 weeks thereafter
through week 24 [21]. Mean productivity (as measured by the VAS) in
the infliximab group increased from 4.2 at baseline to 6.4 at week
24, compared with an increase from 4.3 to 5.1 in the placebo group.
In IMPACT 2, a large clinical trial involving patients with
psoriatic arthritis, a similar improvement in productivity was
observed [22].
At week 50, improvements in productivity and role-emotional and
role-physical scores were sustained with infliximab maintenance
therapy. For placebo patients who had crossed over to infliximab at
week 24, improvements in productivity and role-emotional and
role-physical scores approached those seen in patients who had
received infliximab maintenance therapy from baseline. These scores
improved after initially worsening relative to baseline at weeks 10
and 24 but remained lower in the placebo crossover patients
compared with infliximab-randomised patients at week 50. With
continued infliximab therapy, the scores in placebo-randomised
patients would be expected to improve to levels similar to those of
infliximab-randomised patients.
The current data provide further support for the association
between disease severity and the productivity VAS. Among patients
with more severe psoriasis (PASI >15), the negative impact on
productivity was more pronounced when compared with those who had
less severe disease (figure 2). However, an
impaired productivity was also noted in patients with a PASI of 5
or less, suggesting that maximal clearance of psoriasis is an
important treatment goal. Results of this investigation and those
reported from the IMPACT 2 study [22] confirm that infliximab
therapy not only improves skin and joint symptoms, but also at
least partially normalizes productivity in patients with psoriasis
or psoriatic arthritis.
It may be regarded as a limitation of the study that
productivity was assessed using self-reported parameters such as
the VAS and role-physical and role-emotional domains of the SF-36.
However, previous studies provide support for construct validity
and sensitivity to change of the productivity VAS [21, 22]. These
studies found a strong correlation between the productivity VAS and
parameters of clinical disease severity and quality of life,
supporting the validity of this instrument in assessing
productivity. The correlation between the productivity VAS and both
PASI response and DLQI results in this study further support the
validity of the VAS. Not only did the VAS correlate with disease
severity in the current study, but the magnitude of the correlation
fell within the range of patient-reported productivity scores in
previous studies [29, 30]. Furthermore, the role-emotional and
role-physical scores of the SF-36 have been shown to correlate with
employment outcomes [31].
In examining the improvement in productivity scores observed in
this study, it is important to assess whether these changes are
clinically meaningful. The improvement in productivity VAS exceeds
half the baseline standard deviation, which has been found to
correspond to the threshold for meaningful change for patient
reported outcomes. Further, the percent improvement from baseline
of 22.5% also allows us to interpret the magnitude of benefit.
Changes in the role-emotional and role-physical scales were also
clinically meaningful based on the change of approximately 1/2 of
the baseline standard deviation [25]. Further studies that attempt
to directly observe productivity improvements will be needed to
confirm the observation of this study, although such studies are
both challenging to undertake and methodologically complex.
In summary, using data from a large clinical trial, we found
that productivity was impaired in a large sample of patients with
active moderate-to-severe plaque psoriasis and significantly
improved during treatment with infliximab, parallel to the
reduction in psoriasis signs and symptoms and the improvement of
HRQoL parameters. The beneficial effect of infliximab on patients’
productivity was observed at week 10 and largely sustained during
maintenance therapy for up to one year. Because loss of
productivity is an important contributor to the indirect costs of
psoriasis, our findings may be relevant for the pharmacoeconomic
assessment of treatments such as infliximab. However, more research
is needed to quantify the economic burden of psoriasis, including
the impact of diminished work productivity, and to more fully
understand the effect of therapeutic intervention.
Acknowledgements
Financial Support: Centocor and Schering-Plough Corp. supported
this study. Conflicts of Interest: Employment: Drs. Bala, Wu,
Guzzo, and Dooley and Ms. Li and Ms. Eisenberg (Centocor, a Johnson
& Johnson company), Dr. Guzzo (previous employee of Merck), and
Dr. Wu (previous employee of Bristol-Meyers Squibb); Consultancies:
Dr. Reich (Abbott, Biogen-Idec, Centocor, Schering-Plough, Essex,
Serono, Wyeth), Dr. Nestle (Centocor, Schering-Plough, Serono,
Biogen-Idec, Genentech, Galderma), and Dr. Griffiths (Abott,
Serono, Biogen, Novartis, Centocor, Schering-Plough, Wyeth, Novo
Nordisk, Astra-Zeneca, UCB-Celltech, Galderma); Honoraria: Dr.
Reich (Abbott, Biogen-Idec, Centocor, Schering-Plough, Essex,
Serono, Wyeth), Dr. Nestle (Centocor, Schering-Plough, Serono,
Biogen-Idec, Genentech, Galderma), and Dr. Griffiths(Schering A.G.,
Essex Pharma, Stiefel, Amgen, Serono, Wyeth, Syngento); Stock
ownership or options: Drs. Wu, Bala, Guzzo, and Dooley and Ms. Li
(Johnson & Johnson) and Dr. Guzzo (Merck); Expert testimony:
Dr. Griffiths (Serono); Grants: Dr. Reich (Biogen-Idec), Dr. Nestle
(Schering-Plough, Biogen-Idec), Dr. Griffiths (Serono, Wyeth,
Schering-Plough, Novartis, Leo, Galderma, Stiefel, Biogen, Genmab,
Syngenta); Patents: Dr. Guzzo (a method for treating pediculosis
capitis infestation); Patent applications: None; Royalties: None.
Editorial support: We are indebted to C. Arnold and
J. Barrett, of Centocor.
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