Objectives: Everolimus, a proliferation signal inhibitor with disease-modifying properties, may be useful in treating rheumatoid arthritis (RA). This proof-of-concept study assessed efficacy and safety of everolimus in combination with methotrexate (MTX) in patients with refractory RA.
Methods: A multi-centre, randomised, double-blind, placebo-controlled trial was performed in 121 patients with active RA receiving MTX. Patients were randomised to receive everolimus (6 mg/day) or placebo. The primary endpoint was the American College of Rheumatology criteria for a 20% improvement in measures of disease activity (ACR20) at 12 weeks.
Results: There was a rapid onset of action and at 12 weeks the ACR20 response rate was significantly higher in the everolimus group (36.1%) than in the placebo group (16.7%; p = 0.022). Improvements from baseline in tender and swollen joint counts, patient’s assessment of pain, and patient’s and physician’s global assessment of disease activity were significantly greater after treatment with everolimus. The most common adverse events (AEs) in the everolimus group were gastrointestinal (52.5% vs 31.7% in the placebo group), skin (29.5% vs 8.3%), and nervous system disorders (21.3% vs 10.0%); AEs leading to treatment discontinuation were reported for 16.4% and 10.0% of patients, respectively. Changes in haematological parameters, liver function tests, and lipid levels occurred more frequently with everolimus compared to placebo, but were mild and reversible.
Conclusions: The study indicates that everolimus plus MTX provides clinical benefit with an acceptable safety and tolerability profile. It may offer a new treatment option in RA patients with inadequate response to MTX.
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Rheumatoid arthritis (RA) is a chronic inflammatory disease that causes progressive joint damage leading to functional disability and decreased life expectancy.1 Autoimmune responses drive local inflammation, culminating in erosion of cartilage and bone. Although understanding of the aetiology remains incomplete, it is known T cell-dependent and -independent pathways contribute to articular destruction.2–6
Methotrexate (MTX), demonstrates rapid onset of action, superior efficacy and tolerability, yet response may be limited by disease unresponsiveness or toxicity.7–9 Addition of other disease-modifying antirheumatic drug TX, yet safety and efficacy issues currently limit the use of oral DMARDS in patients with an inadequate response to MTX.12
Everolimus (Certican, Novartis Pharma AG, Switzerland) is a proliferation signal inhibitor (PSI) with a potential influence on immunological and non-immunological components of RA. By blocking FKBP12–rapamycin-associated protein (FRAP) kinase activity following interleukin (IL)-2 stimulation of T cells, everolimus prevents the clonal expansion of activated T cells, and also inhibits vascular smooth muscle cell proliferation.13 Recent data suggest that up-regulation of the FRAP signalling pathway may contribute to the invasive behaviour of synovial fibroblasts.14 This pathway may therefore be an important therapeutic target in RA, since preliminary studies have demonstrated in vitro inhibition of synovial cell proliferation by everolimus. In addition, everolimus also suppresses osteoclast activity and thus has the potential to influence bone erosion in RA (data not shown).
Because of its multiple and novel actions in RA, we performed an exploratory study to determine whether the combination of everolimus and MTX could provide additional benefit in patients suffering from active RA despite treatment with MTX. Based on trials in transplantation, an oral dose of 6 mg once daily was selected.15
A 12-week multi-centre, randomised, double-blind, placebo-controlled, parallel-group, proof-of-concept study that compared the use of everolimus or placebo in combination with MTX in patients with active RA, partially responsive to MTX.
The study was performed at 16 centres (in Europe and America) between March 2002 and July 2003. The primary objective was to demonstrate the efficacy of everolimus in combination with MTX versus MTX alone in patients with active RA lacking adequate response to MTX. Furthermore, the safety and tolerability of everolimus in combination with MTX were assessed, and time to onset of clinical response and disease flare after discontinuation of the study drug were determined. Finally, pharmacokinetics of everolimus and exposure–response relationships were analysed.
Eligible patients at each centre were randomly assigned to receive everolimus (6 mg orally once daily) or placebo for 12 weeks. The dose of everolimus was reduced in patients with a platelet count of <100×109/litre or a neutrophil count of <1.5×109/litre. MTX and folic acid (5–10 mg/week) continued. A reduction in the dose of MTX to ⩽7.5 mg/week was allowed for patients with an increase in transaminase level of >3 times the upper limit of the normal range (ULN). Non-steroidal anti-inflammatory drugs (NSAIDs) or prednisone could be used if the dose was stable. The use of intra-articular corticosteroids or potent opioids was prohibited during the treatment period, and analgesics were not allowed during the 12 h preceding efficacy assessment.
The study consisted of a screening, baseline, 12-week treatment, and a 12-week follow-up period. Clinical, laboratory, and safety assessments were conducted at screening, baseline, weeks 1, 2, 4, 8, and 12 of treatment, and every 4 weeks during follow-up. Patients who discontinued study medication before week 12 were followed up at scheduled visits.
The study was approved by local Institutional Review Boards or Ethics Committees and was conducted in accordance with guidelines established by the US Code of Federal Regulations and the Declaration of Helsinki. All patients gave written informed consent.
Patients were at least 18 years old, and had had active RA for at least 6 months before study entry with inadequate response to MTX. Active RA was defined as at least 6 swollen and 9 tender joints (evaluating 58 joints for swelling and 60 joints for pain); in addition, one of the following conditions had to be present: erythrocyte sedimentation rate (ESR) >28 mm/h, C-reactive protein (CRP) level >15 mg/litre, or morning stiffness with a duration of > 45 min. All patients had received MTX for at least 16 weeks and were on a stable dose (⩾7.5 mg/week) for at least 8 weeks before study start. Patients on NSAIDs or prednisone (not exceeding 10 mg/day) were eligible if the doses had been stable in the 4 weeks preceding the study period.
Patients were excluded if they had an American College of Rheumatism (ACR) functional classification of IV, had used infliximab in the preceding 3 months or other DMARDs within 4 weeks, or had abnormal laboratory parameters.
Disease activity was assessed according to the ACR criteria and based upon: swollen joint count (58 joints), tender joint count (60 joints), patient’s assessment of pain (on a 100-mm visual analogue scale (VAS)), patient’s global assessment of disease activity (VAS), physician’s global assessment of disease activity (VAS), patient’s assessment of disability according to the Health Assessment Questionnaire (HAQ), and the acute phase reactant (ESR or CRP) level.
The primary efficacy variable was the proportion of patients in each group who met the ACR criteria for a 20% improvement in measures of disease activity (ACR20) for improvement at week 12. The ACR20 criteria define clinical improvement as 20% improvement in tender and swollen joint counts, as well as a 20% improvement in at least three of the other five variables. Other assessments included the individual components of the ACR criteria, ACR50 and ACR70 response rates, and time to disease flare (defined as return of the total swollen and tender joint count to baseline values). Clinical response was also assessed using the modified 28-joint Disease Activity Score (DAS28).16–18
Safety assessments included adverse event (AE) reports, laboratory assays and physical examination.
Blood samples for determination of trough everolimus levels were collected at baseline and before dosing at weeks 2, 4, 8, and 12. Concentration–time profiles of everolimus were obtained at either week 2 or week 4 for 30 patients at selected centres to calculate the peak concentration (Cmax) and area under the concentration–time curve over a 24-h dosing interval (AUCτ).
The intent to treat population was used for the efficacy and the safety analyses, and consisted of all randomised patients who received at least one dose of study drug and had at least one post-baseline efficacy or safety evaluation, respectively. All statistical tests were two-sided and used the p = 0.05 significance level.
Sample size calculations were based on the assumption of a 20% to 40% response rate for the placebo group and a 30% higher response rate with everolimus treatment. A sample size of 50 evaluable patients per treatment group was considered adequate to yield 81% power to detect a difference between groups assuming the use of two-sided tests on a binomial distribution.
The primary efficacy analysis assessed whether the proportion of clinical responders in the everolimus group was higher than in the placebo group and was performed with the Fisher exact test. Patients who discontinued the study before week 12 or who received steroid injections were considered to be non-responders. A separate last observation carried forward (LOCF) analysis was not performed. Secondary efficacy outcomes (ACR50 and ACR70 response rates, DAS28, components of the ACR criterion, and time to relapse), the ACR 20 rates for patient subgroups, and changes in laboratory parameters were analysed with the Fisher exact test, the Wilcoxon rank sum test, or the χ2 test, as appropriate.
Of the 121 enrolled patients, 61 were randomised to the everolimus group and 60 to the placebo group (fig 1). In all, 91.7% of the patients completed the study; 8 patients (13.1%) in the everolimus group and 2 patients (3.3%) in the placebo group discontinued before 24 weeks. A total of 45 patients (73.8%) in the everolimus group and 50 patients (83.3%) in the placebo group received study medication for 12 weeks. The frequency of AEs (14.8% in the everolimus group vs 8.3% in the placebo group) accounted for the increase in treatment discontinuation in the everolimus group.
Both groups were comparable. The mean age of patients was 54.5 years, and a majority were female (76.0%) and Caucasian (88.4%). The mean (SD) duration of RA was 9.1 (6.4) years, and the mean tender joint count and swollen joint count were 24.6 (12.5) and 17.0 (9.4), respectively, at baseline. A total of 34 everolimus patients and 30 placebo patients were treated with ⩾15 mg MTX. In addition, 10 everolimus patients and 15 placebo patients had ‘aggressive’ disease at baseline (C-reactive protein (CRP )>20 mg/litre and swollen joint count >10 and rheumatoid factor >40 kIU/litre). DMARDs other than MTX had been used previously by 19% of the patients. Four and five patients in the everolimus and placebo group, respectively, previously used a biologic agent. Previous use of NSAIDs and steroids was comparable between groups.
The mean (SD) daily dose of everolimus over 12 weeks of treatment was 4.6 (1.5) mg (range 0.47–6.0 mg). The mean MTX dose at baseline was 17.5 (14.0) mg/week and 14.1 (5.1) mg/week in the everolimus and placebo groups, respectively. Systemic steroids were used concomitantly by 57% of everolimus treated patients and 55% of placebo patients, with an average dose of 5.11 (3.1) mg/day and 5.15 (3.0) mg/day over the 12-week treatment period in each group, respectively.
The outcome for the primary efficacy endpoint (ACR20 response rate at week 12) was significantly superior in the everolimus+MTX group (36.1%) compared with the placebo+MTX group (16.7%, p = 0.022, table 1). The responder rate increased in the everolimus group between weeks 4 and 8, and differences attained statistical significance at week 12 (fig 2). Response rates in the everolimus-treated group declined gradually after completion of the 12-week treatment. Disease flare-up occurred in two patients per group with a similar time to recurrence (everolimus 6.6 weeks; placebo 6.0 weeks). For all ACR20 components other than the ESR, more everolimus treated patients showed an improvement of at least 20%, compared with the placebo group: swollen joints, 63.9% vs 50.0%; tender joints, 62.3% vs 46.7%; pain, 42.6% vs 30.0%, patient’s assessment of disease activity, 45.9% vs 20.0% (p = 0.004); physician’s assessment of disease activity, 52.5% vs 46.7%; HAQ score, 32.8% vs 30.0%; ESR, 14.8% vs 18.3%; and CRP, 36.1% vs 26.7%.
At week 12, patients receiving everolimus+MTX had significantly improved in most individual components of disease activity, compared with patients receiving placebo+MTX (table 1). No effect on either ESR or CRP was seen with everolimus. Although more patients treated with everolimus+MTX met ACR50 and ACR70, the numbers were too small for valid conclusions to be drawn.
When the clinical response was measured with the DAS28 using the CRP level in the calculations, disease activity improved significantly at 12 weeks in the everolimus group (baseline: 4.62 to 3.45 at 12 weeks) than in the placebo group (baseline: 4.59 to 4.09 at 12 weeks; p = 0.024). The 28-joint count assessment of the DAS28 decreased significantly in the everolimus group for the tender joint count (mean change of –5.5 vs –3.1; p = 0.012) and the swollen joint count (mean change of –5.4 vs –1.9; p = 0.002).
AEs were reported by 88.5% of patients treated with everolimus and 70.0% of patients treated with placebo (table 2). The most common AEs related to everolimus were gastrointestinal disorders, rashes and infections. Most AEs were mild or moderate and resolved during the follow-up period.
The overall frequency of SAEs was low, with two occurring in patients treated with everolimus; one patient with epiglottitis and obstructive airway disorder and one cardiac failure. The incidence of AEs leading to withdrawal of study medication was slightly higher in the everolimus than the placebo group. The difference was mainly due to skin disorders such as acne, rash, and exanthema. There was one death (due to myocardial infarction) in the everolimus group 2 months after treatment.
A significant decrease in leukocyte and neutrophil counts from baseline was noted in the everolimus group at 12 weeks, but values returned to baseline by 24 weeks. Platelet counts also decreased during treatment, but the difference was not significant. None of the patients were leukopenic (⩽2.0×109/litre), yet one patient in each group exhibited neutropenia (⩽1.5×109/litre).
At 12 weeks, values for liver function (alanine aminotransferase (ALT), aspartate transaminase (AST), and alkaline phosphatase) were significantly higher than baseline levels in patients treated with everolimus, but mean values were within the normal range. These increases were reversible, with levels returning to baseline at 24 weeks. Renal function (as measured by serum creatinine) remained stable after treatment with everolimus.
Levels of cholesterol, low-density lipoprotein (LDL) cholesterol, and triglycerides showed a statistically significant but modest increase by 12 weeks in patients receiving everolimus. These values returned to baseline levels after the end of the 12-week treatment. More everolimus-treated patients had lipid elevations exceeding the ULN (cholesterol: 39.3% vs 11.7%; LDL-cholesterol: 19.7% vs 1.7%; triglycerides 44.3% vs 11.7%).
Exposure–activity relationships for everolimus
Pharmacokinetic data for everolimus were collected from 50 of the 61 everolimus-treated patients. Everolimus trough levels remained stable, with a mean (SD) of 7.7 (3.9) ng/mL, and 10th and 90th percentile values of 3.4 ng/mL and 12.3 ng/mL, respectively. Steady state AUC profiles obtained from 18 patients demonstrated a peak concentration of 43 (25) ng/mL at a median of 1 h (range, 1–5 h) after dosing. The AUC over the 24-h dosing interval was 367 (177) ng/h/mL.
ACR20 efficacy responses at week 12 were independent of everolimus trough concentrations over the exposure range achieved in this study.
This study showed that the combination of everolimus and MTX was superior to MTX alone in alleviating signs and symptoms of RA in patients partially responsive to MTX. The ACR20 response rate was significantly higher and the improvement from baseline in several clinical parameters significantly greater in patients receiving everolimus vs placebo.
MTX has emerged as the treatment of choice for RA, but since many patients do not achieve satisfactory disease control, combination therapy with other DMARDs has been investigated.19–23 As a PSI, everolimus prevents cell proliferation by a mechanism distinct from that of MTX, thereby providing a rationale for use of this agent in combination.
In our study, after 12 weeks of treatment, patients receiving everolimus+MTX had an ACR20 response rate of 36.1% vs 16.7% in patients on placebo. This improvement of 19.4% compares favourably to the reported 24% to 33% enhancement, noted in trials of MTX in combination with etanercept23 and leflunomide.19 Furthermore, everolimus demonstrated clinical improvements (eg, patient’s assessment of disease activity and pain), as early as 2–4 weeks after start of treatment. The clinical significance of the elevated ESR and the slight decrease of the CRP levels noted at 12 weeks in the everolimus-treated group need to be elucidated further.
The combination of everolimus and MTX showed an acceptable tolerability. Everolimus-treated patients experienced a higher incidence of AEs, but SAEs or infections were infrequent and comparable between groups. Ten patients in the everolimus arm and six in the placebo group discontinued treatment due to AEs, with an increased frequency of skin disorders in the everolimus group accounting for this difference. One patient in the everolimus group died 2 months after treatment of a myocardial infarction, unrelated to the treatment, according to the investigator.
A decrease in neutrophil, leukocyte, and platelet counts at 12 weeks was noted more frequently in everolimus patients, values started to return to baseline levels during the treatment phase, indicating that myelosuppression was transient which is consistent with previous experience.25 Elevated levels of serum lipids in the everolimus group returned to baseline, and no patient in this study required initiation of cholesterol-lowering medication. No increased cardiovascular morbidity or mortality have been reported in transplant patients receiving everolimus.25 It is possible that the antiproliferative effect of everolimus on vascular smooth muscle cells may counteract any enhanced cardiovascular risk posed by elevated lipid levels.26
Elevations of ALT, AST, and alkaline phosphatase levels were noted by 12 weeks in patients receiving everolimus+MTX. However, mean values remained within the normal range, and all parameters returned to baseline levels by 24 weeks. Abnormalities in liver function tests were more frequent in everolimus patients, but not considered clinically meaningful. The everolimus–MTX combination had no effect on renal function, as creatinine levels remained stable. This confirms the lack of nephrotoxicity specifically related to everolimus.
The pharmacokinetic data demonstrated stable everolimus trough levels during treatment (mean (SD): 7.7 (3.9) ng/mL), well within the therapeutic window of immunosuppression.24 The exposure–efficacy relationship between trough levels and ACR response was flat over the exposure range achieved in this study. This suggests that the contribution of everolimus to the efficacy of an MTX-based regimen in RA may be near maximal in this population. Exposure-safety evaluations indicated that myelosuppression and hyperlipidemia may increase in frequency at everolimus trough levels higher than 6 ng/mL.
In summary, this proof-of-concept study demonstrates that a combination of everolimus and MTX may be useful for the treatment of RA in patients who have an inadequate response to MTX monotherapy. The treatment was generally well tolerated and no excess safety risk could be detected. These results underscore the potential of everolimus in the management of RA, yet long-term studies of everolimus in combination with MTX are warranted.
Novartis Pharma AG, Basel Switzerland, provided the study medication.
Other members of the RADD2201 study group: Professor P Geusens, Limburgs Universitair Centrum, Diepenbeek, Belgium; Dr W Bensen, Charlton Medical Center, Hamilton, Canada; Dr L Martin, Heritage Medical Building, Calgary, Canada; Dr M A F J van der Laar, Medisch Spectrum Twente, Enschede, The Netherlands; Dr H R van den Brink, Medisch Centrum Alkmaar, Alkmaar, The Netherlands; and Dr K Vos, Academic Medical Center, Amsterdam, The Netherlands.
Funding: Novartis Pharma AG, Basel, Switzerland, funded this study.
Competing interests: KHA and PB are Novartis employees.
Ethics approval: The study was approved by local Institutional Review Boards or Ethics Committees and was conducted in accordance with guidelines established by the US Code of Federal Regulations and the Declaration of Helsinki. All patients gave written informed consent.
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