Introduction
For patients with chronic diseases such as axial spondyloarthritis (axSpA), psoriatic arthritis (PsA), and plaque psoriasis (PsO), treatment goals usually include attaining remission preferably within the first 12 weeks of treatment [
1‐
3]. In instances where disease remission is unlikely, current recommendations state that achieving low disease activity (LDA) can be an acceptable alternative. If remission or LDA has not been reached after 12 weeks, current treatment should be adjusted [
4‐
9]. Patients showing some improvement in disease activity in this time period, but who have not yet achieved the treatment target, may continue with current treatment if they are expected to reach their goal by 24 weeks [
10,
11]. Patients with chronic diseases can experience pain, fatigue, low or depressed mood, and adverse effects of concomitant glucocorticoid use; therefore, another treatment target should be improvement in patient quality of life [
3,
11].
Previous studies in rheumatic diseases and PsO have demonstrated the benefits, with regards to disease remission rates, of treating beyond 12 weeks [
12,
13]. The primary aim of this prospective, non-interventional study was to evaluate the proportion of patients with rheumatoid arthritis (RA), axSpA, PsA, or PsO who, in routine clinical practice, benefit from the continuation of treatment with etanercept (ETN) beyond 12 weeks, even in cases where the defined treatment goal has not been formally attained by week 12. Patient-reported outcomes were also recorded. Results for patients with RA have been published previously [
14]. This article presents data from patients with axSpA, PsA, or PsO. As a result of the small number of patients with PsO, those data are only described briefly, with further details and figures provided as supplementary material.
Methods
Study Design
ADEQUATE was a prospective, multicenter, non-interventional study conducted in Germany. It was designed to evaluate the effectiveness of ETN in patients with RA, PsA, axSpA, or PsO after 12, 24, 36, and 52 weeks of routine treatment. The study design has been described in detail previously [
14].
ETN was prescribed in accordance with the Summary of Product Characteristics (SmPC). The specified contraindications, warnings and precautions for use, undesirable effects, interactions, and posology and method of administration were followed at each investigator’s discretion. After regular initiation of treatment with ETN, patient information was documented for up to 52 weeks. Initial treatment decisions were taken prior to enrollment into the study, and documentation was performed at five regular 12-weekly study visits over the course of the 52-week observation period. Written informed consent was obtained by the treating physician or a designated person prior to patients entering the study. This non-interventional study was conducted in accordance with the Declaration of Helsinki and is registered with the Federal Institute for Drugs and Medical Devices, the Federal Association of Statutory Health Insurance Physicians, and the Head Association of Health Insurers. It is also registered on ClinicalTrials.gov (NCT02486302). The final protocol and subject information and informed consent documentation were reviewed and approved by the Ethics Committee of the Faculty of Medicine of the Goethe University of Frankfurt am Main, Germany (432/14).
Inclusion and Exclusion Criteria
Inclusion criteria were a confirmed diagnosis of RA, axSpA, PsA, or PsO, no prior treatment with ETN (prior treatment with other biologics was permitted), treatment according to the ETN SmPC, and age ≥ 18 years. Exclusion criteria were the contraindications and the special warnings and precautions in the SmPC.
Primary and Secondary Endpoints
The primary endpoints for this study were the proportion of patients achieving remission at week 12 and week 24 of treatment, and the proportion of patients achieving LDA at week 12 and week 24. The criteria for remission and LDA used in this study are listed in Supplementary Table
S1 [
1,
15,
16]. Secondary endpoints were the proportion of patients continuing treatment with ETN despite not achieving remission at week 12, overall incidence of adverse events (AEs), and PROs, e.g., patient global assessment, depression (evaluated using the Patient Health Questionnaire-2 [PHQ-2]), and fatigue and pain (measured by the visual analog scale [VAS]).
Data Collection and Statistical Analyses
Treating physicians collected data at each visit using a case report form. Categorical data were presented as relative frequencies (absolute and adjusted) and numerical data were presented as mean (± standard deviation) or median (range, 25% and 75% quartiles). Missing values were not imputed unless otherwise stated.
Analysis sets were defined as “all documented” (all documented patients), “treated set” (all patients with ≥ 1 post-baseline value including documentation of an AE), and “per protocol set” (all patients without major protocol deviations).
Discussion
In this non-interventional study of patients with axSpA, PsA, or PsO treated with ETN in routine clinical practice, a considerable proportion of patients reached the treatment goal of remission or LDA after 12 weeks of treatment, and this was maintained for up to 52 weeks of treatment. In addition, improvements in PROs such as pain and fatigue were observed across all indications.
These findings are generally in agreement with results for patients with RA from the same study [
14] and are in line with previous real-world observations for TNF inhibitors and other biologics. In a prospective observational study of golimumab as a second-line TNF inhibitor, 33% of patients with axSpA and 59% with PsA achieved ASDAS and DAS28 remission, respectively, at 6 months [
17]. Data from an observational study of patients with PsA showed that a significantly greater proportion of patients receiving ETN monotherapy versus ETN plus cDMARD achieved LDA based on DAS28 < 2.6 (21.1% vs. 24.4%;
p < 0.05) at 52 weeks [
18]. Overall, for patients receiving monotherapy or combination therapy, DAS28 remission criteria were attained after 12 weeks and remained stable through to week 52 in this patient population. In a post hoc analysis of the non-interventional, prospective GO-NICE study of golimumab as first-, second-, or third-line treatment, 50–76% of patients with PsA were in Psoriatic Arthritis Response Criteria remission [
19]. In another study that pooled data from patients with PsA enrolled in 12 European registries and receiving TNF inhibitors, the remission (DAS28 < 2.6) rate at 6 months was 56% [
20]. In the real-world PsABio study, the interleukin-12/23 inhibitor ustekinumab was compared to TNF inhibitors. After 1 year’s treatment, 22% of patients receiving ustekinumab were in clinical Disease Activity Index for Psoriatic Arthritis remission, compared with 31% of patients receiving TNF inhibitors [
21]; LDA rates were 56% and 67%, respectively.
Similarly, the PRISTINE study showed that 37.2% of patients with PsO treated once weekly with 50 mg of ETN achieved a Psoriasis Area and Severity Index (PASI) 75 (PASI75) response after 12 weeks (62.4% achieved PASI75 when ETN 50 mg was administered twice weekly). The proportion of patients attaining a PASI75 response increased to 59.9% after 24 weeks (78.2% when treated with 50 mg ETN twice weekly) [
7]. In a Spanish study of patients with PsO treated with ETN, an increase in the proportion of patients reaching PASI75 was observed, from 59.0% at 12 weeks to 66.3% at 24 weeks [
22]. In addition, a comparison of infliximab, adalimumab, and ETN in Greek patients with RA showed an increase in DAS28 response beyond 24 weeks and up to 8 years of treatment [
23].
While there were numerical increases in the proportion of patients achieving remission or LDA throughout the course of the current study, 15% of patients discontinued treatment because of insufficient response. This observation, along with the high proportion of patients subsequently receiving another bDMARD, suggests that investigators based their treatment decisions on the treatment goals detailed in the relevant guidelines [
3,
15,
24]. Nevertheless, a sizable proportion of patients received ETN until the end of the study despite not reaching their treatment target. These patients were seen to have improvements in PROs such as depression, fatigue, and pain. This indicates that for some patients, objective assessment of disease activity may not be the only reason for treatment continuation in clinical practice; patients may benefit from staying on a particular treatment simply because of substantial improvements in PROs. Although switching treatment when treatment goals have not been reached after 12–24 weeks has been shown to be a beneficial approach [
25‐
29], switching is not always possible because of patient comorbidities or contraindications.
The current study demonstrates that extending treatment with ETN beyond 12 weeks has the potential to expand the proportion of patients achieving the treatment goal of remission or LDA. Indeed, for some patients, this did not happen until after 24 weeks of treatment. These findings, together with the improvements in PROs seen in patients who reached treatment goal at a later point in the study, indicate that continuing treatment with ETN can be of benefit to patients with a range of rheumatic diseases and PsO, even for those who do not reach treatment goals after 12 or 24 weeks.
Notable AEs related to glucocorticoid treatment include decreased quality of life and cardiovascular effects, which are generally dose-dependent [
30]. In the current study, while there was a decrease in concomitant glucocorticoid use across all patient populations, half of those with axSpA and PsA remained on long-term, low-dose glucocorticoid treatment throughout the study. This highlights the need for improved disease management in accordance with new treatment guidelines. Systemic glucocorticoid treatment should be used with caution and at the lowest effective dose in patients with PsA [
24]. Long-term treatment with systemic glucocorticoids is not recommended in patients with axSpA [
1].
Numerically, rates of remission and LDA were higher in patients with axSpA who had not received any prior or concomitant glucocorticoids compared with patients who had received at least one dose. This indicates that responses in patients with axSpA may be mostly due to the effect of ETN. While we cannot explain the numerically lower rates in patients who received prior or concomitant glucocorticoids, it is important to note the low number of patients in this group preventing definite conclusions based on these results alone. In patients with PsA who had not received any prior or concomitant glucocorticoids, rates of remission were numerically lower at week 12 but similar at week 24. Rates of LDA were similar in both groups at week 12 and week 24. This indicates that glucocorticoids may have had a small add-on effect on response and LDA rates in patients with PsA. However, without a comparator group receiving glucocorticoids alone and studies designed to detect glucocorticoid treatment effects, the exact effects of glucocorticoids are difficult to determine. Response rates observed at 12 weeks of treatment with ETN were highest in patients with PsA, followed by those with axSpA. This observation may have been an artifact of the chosen disease activity score. DAS28 was used for PsA, in line with guidelines at the time of study conception [
15,
24]; however, the American College of Rheumatology/European League Against Rheumatism guidelines now recommend using the Simplified Disease Activity Index and the Clinical Disease Activity Index scores to measure remission and LDA [
11]. However, these scores tend to yield lower rates of remission than DAS28, as observed in this study. Similarly, the Disease Activity in PsA score, which is now recommended for assessing responses in patients with PsA [
3], may yield different rates of remission or LDA compared with DAS28.
In this study, the proportion of patients with PsO who achieved remission at 12 or 24 weeks was markedly lower than that observed in previous studies with ETN or other TNF inhibitors [
31]; this is likely due to the definition of remission used here (PASI75 and Dermatology Life Quality Index [DLQI] ≤ 1; Supplementary Table
S1). DLQI ≤ 1 is more likely to be achieved by patients with PASI90, suggesting that the definition used for remission in PsO is important when interpreting results. Absolute PASI score ≤ 2 (corresponding with PASI90 and representing Physician’s Global Assessment clear/almost clear) is now frequently used to inform treatment decisions for PsO in the clinical setting [
27]. In the current study, a sizable proportion of patients with PsO achieved PASI75 at week 12 and week 24 (34% and 57%, respectively; Supplementary Fig.
S4), indicating good responses to ETN in this patient population.
Study Limitations
Inherent limitations of non-interventional, observational studies are the risk of selection/ascertainment bias and the inability to attribute causation. As a result of the current study’s duration of 52 weeks, no conclusions on long-term outcomes can be drawn. A further limitation is the decreasing number of observations over time. Reasons for discontinuation included switching to a different treatment because of AEs or insufficient effectiveness; in addition, some patients were lost to follow-up. This leads to a potential risk of bias due to missing data. However, randomized controlled trials usually have much stricter inclusion and exclusion criteria, and are therefore not representative of the general population of patients eligible for a certain medication. Data from the German biologics registry RABBIT showed that only 21–33% of patients included in the registry would have been eligible for a randomized controlled trial [
32]. Remission and LDA criteria were defined on the basis of guidelines available at the time of study conception. Since then, updated guidelines for axSpA [
5,
6], PsA [
4,
7‐
9], and PsO [
7,
8] have been published. A decrease in the number of patients over time (due to discontinuation of treatment or lost to follow-up) is common in non-interventional studies [
22,
23]. Finally, documentation may be incomplete as only routine clinical investigations are included because of the non-interventional nature of the study, which may vary from practice to practice.
Declarations
Conflict of Interest
Eugen Feist received consulting/speaker fees from AbbVie, BMS, Celgene, Galapagos, Lilly, Medac, Novartis, Pfizer, Roche, Sanofi, Sobi, and UCB. Xenofon Baraliakos received honoraria or grants from AbbVie, Amgen, Biocad, BMS, Celltrion, Chugai, Gilead, Janssen, Lilly, Novartis, Pfizer, Roche, Sandoz, and UCB. Frank Behrens received research grants from Bionorica, Celgene, Chugai, Janssen, Pfizer, and Roche; and consulting/speaker fees from AbbVie, Amgen, Boehringer Ingelheim, Celgene, Chugai, Janssen, Genzyme, Gilead, Lilly, MSD, Novartis, Pfizer, Roche, Sandoz, Sanofi, and UCB. Diamant Thaçi was consultant, investigator, and speaker, and has participated in advisory boards for AbbVie, Almirall, Amgen, Biogen Idec, BMS, Celgene, Janssen-Cilag, LEO Pharma, Lilly, MSD, Novartis, Pfizer, Regeneron, Sanofi, and UCB; and has received research/educational grants from AbbVie, Leo-Pharma Celgene Corp, and Novartis. Anja Plenske, Pascal Klaus, and Thomas Meng are employees and shareholders of Pfizer.