Topical chlormethine gel in the treatment of mycosis fungoides: A single-center real-life experience and systematic review of the literature.

Gel formulation of chlormethine (CG) has gained a preeminent role among therapies available for mycosis fungoides (MF). To evaluate the frequency of use of CG for MF treatment and to determine the limits and potentialities of CG in a real-world setting. A systematic review of articles published prior to October 2021 was performed. Articles were included in the review if a full-text English version was available. MEDLINE (PubMed), Scopus, and Web of Science were each queried from their date of inception with the following terms: "mechlorethamine gel", "chlormethine gel", and "mycosis fungoides". The reference lists of the studies retrieved were searched manually. Moreover, this study included all consecutive patients with different stages of MF (from IA to IIB) who started treatment with CG gel between July 2020 and May 2021. Data of the literature were compared to our single-center real-life experience. Of the surveyed literature, 11 publications were included in the final analysis describing a total of 548 patients with MF. Eleven patients with a median (standard deviation) age of 66 years (15.1) were enrolled and followed up, receiving CG (0.02% chlormethine HCl). Response to treatment resulted higher (90.1%) in our study population than in other real-world experiences published in literature. This systematic review supports the role of CG for MF treatment, showing its limits and potentialities. Our single-center real-life experience revealed an elevated percentage of clinical response with high safety and tolerance, demonstrating its versatile use with dose and application rate adaptability.

Biologic therapy for acrodermatitis continua of Hallopeau: Successful treatment with secukinumab and review of the literature.

Acrodermatitis continua of Hallopeau (ACH) is a rare pustular psoriasis variant refractory to many conventional treatments. We report the successful treatment with secukinumab of a patient with a long history of ACH with marked onychodystrophy with frank pustulosis on the nail bed and with accompanying arthritis. Blockade of the IL-17 receptor A has shown promise in the treatment of psoriatic erythroderma and generalized pustular psoriasis not responsive to conventional treatment. A rapid response was observed in our patient, in both skin lesions and arthritic symptoms, underlining the ability of secukinumab to improve symptoms beyond those of plaque psoriasis.

Successful treatment of psoriatic crumbly nails with ustekinumab.

Nail involvement can place a significant burden on patients as a result of functional damage and psychosocial problems, leading to major repercussions on the quality of life. There is strong evidence that nail psoriasis can often be difficult to treat. We report a 69-year-old man with severe onychodystrophy, onycholysis, and pain in the hands; he had been previously treated with topical and systemic traditional therapies without satisfactory response. The patient showed multiple severe psoriatic crumbly nails (nail psoriasis severity index [NAPSI] score of 69) and started ustekinumab treatment at standard dosage of 45 mg fl.s.c. After 24 weeks, both nail matrix and nail bed disease showed marked improvement and the patient continued therapy with ustekinumab (NAPSI 0 at week 104). At week 136 (September 2015), the patient had been complaining of hands pain (visual analogue scale pain: 80) and ultrasonographic (US) evaluations found a synovial proliferation with effusion on metacarpophalangeal joints. The patient continued therapy with ustekinumab, adding methotrexate 10 mg fl.s.c/week. In November 2016, the patient showed a remission of symptoms; clinical and US evaluations did not find signs of synovitis. Methotrexate treatment was suspended and currently the patient reached more than 4 years of ustekinumab treatment without sign and symptoms of synovitis.

Use of biological drugs in patients with psoriasis and psoriatic arthritis in Italy: Results from the PSONG survey.

This Italian multicenter retrospective study compared the drug survival and efficacy of different anti-TNF agents in psoriasis (PsO) and psoriatic arthritis (PsA) patients. A database of PsO/PsA patients treated with adalimumab, etanercept, and infliximab from May 2013 to May 2014 was analyzed. PASI 75, 90, and 100 was calculated at each time point to evaluate efficacy. Drug survival rate and probability of maintaining PASI response were evaluated. The impact of dependent variables on probability of PASI 75 loss was evaluated by logistic regression. 1,235 patients were included, 577 with PsO and 658 with PsA. Highest survival rates were observed with adalimumab followed by etanercept and infliximab in PsO and PsA patients. The probability of maintaining PASI response was significantly higher for adalimumab followed by infliximab. For PsO patients, the odds of losing PASI 75 was higher in etanercept-treated patients (OR: 8.1; 95% CI: 4.2-15.6, p < .001) or infliximab (OR: 6.6; 95% CI: 2.6-16.3, p < .001) vs. adalimumab. Likewise, for PsA patients the odds of losing PASI 75 was higher in etanercept-treated patients (OR: 2.3; 95% CI: 1.4-3.8, p = .01) or infliximab (OR: 2.2; 95% CI: 1.1-4.1, p = .018) vs. adalimumab. Adalimumab could be the best therapeutic option over other anti-TNF agents for the treatment of PsO and PsA patients.

Golimumab in patients affected by moderate to severe psoriatic arthritis: an open-label study in thirty-two patients previously treated with other biologics.

BACKGROUND: Clinical trials have demonstrated the efficacy of golimumab (GLB) in improving the signs and symptoms of psoriatic arthritis (PsA). OBJECTIVE: The aim of this study was to evaluate the efficacy of GLB in monotherapy in patients affected by PsA with cutaneous involvement unresponsive to other anti-tumor necrosis factor-α (TNF-α) agents. METHODS: This study included 32 patients treated with GLB as monotherapy, at a dosage of 50 mg, subcutaneously, every 4 weeks. Patients were divided into 3 groups (A, B, and C) according to their number of previous anti-TNF-α treatments (1, 2, or 3). Clinical and laboratory evaluations were performed at weeks 0, 12, and 24. RESULTS: All patients showed significant improvement of their clinical, inflammatory, and quality of life indexes. CONCLUSION: Data suggest that GLB can be successful and safe in patients affected by PsA with skin involvement previously treated with other anti-TNF-α agents.

Chlormethine gel in combination with other therapies for treatment of mycosis fungoides: a review with patient cases.

Topical chlormethine gel has been approved as monotherapy for treatment of adult patients with mycosis fungoides (MF), the most common form of cutaneous T-cell lymphoma. In clinical practice, chlormethine gel is often combined with other skin-directed or systemic therapies to optimize response and target recalcitrant lesions. Positive outcomes with combination regimens using chlormethine gel and topical corticosteroids, phototherapy, retinoids, methotrexate, or interferon-α have been reported in literature. However, there are no treatment guidelines on the use of combination regimens with chlormethine gel. To provide real-world evidence and guidance on the use of chlormethine gel combination regimens, several cases of patients treated with chlormethine gel combined with phototherapy (n = 5), retinoids (n = 16), or mogamulizumab (n = 3) are presented. These different combination regimens showed promising results. Most patients had a complete or partial response following treatment and the combinations were well-tolerated over extended treatment periods. Patients receiving chlormethine gel with retinoids had long-term periods of remission, even after treatment discontinuation. Durations of response of up to 3 years were observed in these patients. This long-term disease control may be the result of disease-modifying effects of chlormethine. Previous studies have shown targeted reductions in malignant T-cell clones in patients treated with chlormethine gel as well as improved post-treatment responses. Further research is needed to determine the effectiveness and safety of combination treatment regimens with chlormethine gel and to assess the impact chlormethine gel has on disease control.

Effectiveness and tolerability of chlormethine gel for the management of mycosis fungoides: a multicenter real-life evaluation.

Background: Topical chlormethine (CL) is recommended as a first-line treatment for early-stage mycosis fungoides (MF) and in 2017, the European Medicines Agency approved the CL gel formulation to treat adult patients. More recently, to increase patient compliance and adherence, clinicians have developed flexible protocols that allow the concomitant use of CL gel with topical corticosteroids in daily practice regimens. Therefore, sharing real-life data on CL gel use and side effects management may help improve the use of this agent. Objectives: To expand knowledge about the actual use of CL gel in patients with MF, the present study assessed the improvement of MF skin lesions after CL gel treatment and provided information on the management of cutaneous adverse events (AEs) in a real-life setting. Methods: This was an Italian retrospective study conducted among six dermatology referral centers. Patients ≥18 years affected by MF and in treatment with CL gel (160 µ/g), alone or in combination according to routine clinical practice, between December 2019 and December 2021 were considered. The study's primary aim was to evaluate the effectiveness of CL gel in terms of overall response rate (ORR) after 3 months of treatment. Results: A total of 79 patients (61% male) with different stages of MF (84% early stage) were included. CL gel was prescribed mainly in association with topical corticosteroids (66% of patients). ORR after 3 months of treatment was 42%, with no differences between early- and advanced-stage MF. Response rates improved over time up to 97% after 18 months of treatment. Overall, 66 AEs were reported in 67% of patients; most were hyperpigmentation (45%) and irritant contact dermatitis (37%). Six AEs led to treatment discontinuation, and five out of six (83%) patients who reported these events resumed treatment after interruption. No AEs were classified as severe. Conclusions: Our observations support the use of CL gel in patients with early- and advanced-stage MF, making it a valuable treatment option.

Autoimmune bullous dermatoses in cancer patients treated by immunotherapy: a literature review and Italian multicentric experience.

Cutaneous immune-related adverse events are frequently associated with immune checkpoint inhibitors (ICIs) administration in cancer patients. In fact, these monoclonal antibodies bind the cytotoxic T-lymphocyte antigen-4 and programmed cell death-1/ligand 1 leading to a non-specific activation of the immune system against both tumoral cells and self-antigens. The skin is the most frequently affected organ system appearing involved especially by inflammatory manifestations such as maculopapular, lichenoid, psoriatic, and eczematous eruptions. Although less common, ICI-induced autoimmune blistering diseases have also been reported, with an estimated overall incidence of less than 5%. Bullous pemphigoid-like eruption is the predominant phenotype, while lichen planus pemphigoides, pemphigus vulgaris, and mucous membrane pemphigoid have been described anecdotally. Overall, they have a wide range of clinical presentations and often overlap with each other leading to a delayed diagnosis. Achieving adequate control of skin toxicity in these cases often requires immunosuppressive systemic therapies and/or interruption of ICI treatment, presenting a therapeutic challenge in the context of cancer management. In this study, we present a case series from Italy based on a multicenter, retrospective, observational study, which included 45 patients treated with ICIs who developed ICI-induced bullous pemphigoid. In addition, we performed a comprehensive review to identify the cases reported in the literature on ICI-induced autoimmune bullous diseases. Several theories seeking their underlying pathogenesis have been reported and this work aims to better understand what is known so far on this issue.

Ustekinumab for treatment of plaque psoriasis in a patient with Down syndrome.

Down syndrome (DS) is the most common chromosomal disorder and a major cause of mental retardation. Down syndrome phenotype is complex and may present a combination of dysmorphic features, congenital heart disease and immunological deficiency. Psoriasis it has been noted to be 0.5%-8% in patients with DS and numerous factors can limit the use of therapeutic options, in particular long-term organ-specific toxicity, and the risk of opportunistic infections. It is still debated whether the use of biologics in the treatment of DS-related psoriasis is safe. We have valuated the efficacy and safety of ustekinumab treatment in-patient with DS suffering from plaque type psoriasis. A 31-year-old patient suffering from plaque type psoriasis since the age of 14, showed a PASI score of 12 after the failure of anti-TNF agents. We switched the patient to ustekinumab treatment at the standard dose of 45 mg subcutaneously initially and 4 weeks later, followed by 45 mg every 12 weeks. The patient showed a significant improvement of the PASI score already after 4 weeks of treatment and further improvements were observed throughout the treatment. We report the first case of DS-correlated psoriasis patient treated for a long-term period with various biologics, showing a satisfactory safety profile undergoing treatment. In our experience, ustekinumab has demonstrated a high efficacy, relatively rapid onset of action, favorable safety profile, and can be considered a good treatment option even after failure to respond to other biologic therapies in patient with DS.

Effects of TNF-α inhibition on pre-clinical enthesitis: observational study on 49 psoriatic patients.

BACKGROUND: Enthesitis is a hallmark of psoriatic arthritis (PsA) and echographic ultrasounds (US) represent a support for diagnosis of pre-clinical signs of enthesitis in asymptomatic patients at high risk for advanced forms. Early treatment with anti-TNFα could prevent permanent damage contrasting the degenerative course of the disease. OBJECTIVES: To evaluate the effects of adalimumab on echographic and preclinical enthesitis signs in patients affected by plaque psoriasis. METHODS: 49 psoriatic patients undergoing adalimumab treatment for plaque-type psoriasis were subjected to echographic screening for identifying pre-clinical signs of enthesitis. Patients underwent clinical and ultrasonographic examination of hands, elbows and knees before starting adalimumab and after 24 and 48 weeks of treatment. RESULTS: We observed a reduction of the total number of echographic abnormalities and a significant decrease of the thickness of quadriceps tendons at week 24 and week 48. Furthermore, there was no evidence of significant articular damage progression during the entire study duration. CONCLUSIONS: Entheseal ultrasonography may be used for preclinical diagnosis of PsA.Our study demonstrates that early detection and management with adalimumab leads to a block of articular damage progression. On quadriceps tendon, adalimumab has shown to be effective with a significant thickening reduction at week 24 and 48.

Methyl aminolaevulinate photodynamic therapy for the treatment of hidradenitis suppurativa and pilonidal cysts.

Hidradenitis suppurativa (HS) and pilonidal cysts are chronic, inflammatory skin conditions involving apocrine gland-bearing skin. Treatment is limited and unsatisfactory. Photodynamic therapy (PDT) has been reported to be safe and effective in the treatment of several off-label skin conditions. We report the case of a 29-year-old man affected by HS and pilonidal cysts since the age of 21. In the past, the patient was treated with antibiotics, corticosteroids and retinoids, without significant clinical improvement. Treatment with methyl aminolaevulinate (MAL)-PDT was started. A topical MAL cream (Metvix) was applied to the affected areas with an occlusive dressing for 3 h and irradiated with a red light source. Therapy was repeated every 15 days for a total of nine applications. The patient completed a 6-month follow-up and achieved an almost complete clinical remission of the skin lesions (80%) and complete resolution of the itching and discomfort. This is the first case of HS associated with pilonidal cysts treated with MAL-PDT. MAL-PDT was effective and well tolerated in our patient. The costs of this therapy represent an important limitation, taking into account the high number of sessions that were performed compared with non-melanoma skin cancers.

Evaluation of alexithymia in patients affected by rheumatoid arthritis and psoriatic arthritis: A cross-sectional study.

Rheumatoid arthritis (RA) and psoriatic arthritis (PsA) are chronic autoimmune diseases leading to joint damage, functional limitation, and disability and are typically associated with several comorbidities. Alexithymia is a personality trait characterized by a disregulation of emotion processing and regulation of emotions that involves a dissociation of emotional and physical responses to life events. A broad association between alexithymia and symptoms as depression, inflammation, and pain has been demonstrated. We aimed at evaluate an association among inflammatory arthritis, as RA and PsA, and alexithymia, and a possible link with clinical characteristics and disease activity.In this cross-sectional study, we enrolled, from January to December 2017, patients affected by RA or PsA referring to the outpatient's clinic of the Rheumatology Unit of the University of Rome Tor Vergata. The 20-item Toronto Alexithymia Scale (TAS-20) was used to assess alexithymia. Disease activity, function, quality of life, and clinimetric indexes were assessed.A total of 50 RA patients and 51 PsA patients were enrolled. The TAS-20 score showed 38.6% (39/101) patients had alexithymia, 26.7% (27/101) patients were in the borderline of alexithymia and 34.7% (35/101) patients did not have alexithymia. A statistical significant association was observed between alexithymia and inflammatory indices (ESR: P = .029, CRP: P = .043) and between alexithymia and clinimetric parameters (ptVAS, pVAS, GH, P < .0001 for all comparisons). A significant trend of association has been demonstrated between alexithymia and female gender and concomitant steroid therapy. No correlations among variables such as age, duration of disease, and comorbidities and alexithymia status were observed.This study suggests that alexithymia assessment should be a part of the comprehensive management of RA and PsA patients.

PsA-Disk, a novel visual instrument to evaluate psoriatic arthritis in psoriatic patients: an Italian derma-rheuma multicentre study.

BACKGROUND: Consensus among dermatologists and rheumatologists in the diagnosis and assessment of musculoskeletal diseases in psoriasis (PsO) patients is needed. This study assesses characteristics of musculoskeletal pain in patients with PsO for the presence of psoriatic arthritis (PsA) and evaluation of a novel 16-item visual instrument (PsA-Disk). METHODS: Data were collected from eight dermatological/rheumatological centres across Italy. Patients with PsO completed PEST (Psoriasis Epidemiology Screening Tool) and PsA-Disk questionnaires during the first visit. A rheumatological visit was performed to confirm the presence of PsA. Both validity and reliability of PsA-Disk were assessed. RESULTS: A total of 573 patients with PsO were examined at the first visit, and 120 (21%) were diagnosed with PsA. Patients with PsA compared with patients with PsO (n = 119) presented statistically significant differences for: nail involvement, PEST score ⩾3, higher erythrocyte sedimentation rate (ESR), Nail Psoriasis Severity Index (NAPSI)-feet, NAPSI-(hands + feet) and PsA-Disk scores (73.9 ± 32.1 versus 58.1 ± 39.8, p < 0.001). Patients with PsA with knee arthritis had higher PsA-Disk scores (98.4 ± 26 versus 71.5 ± 31.9, p = 0.006) that were also correlated with number of swollen (r = 0.2, p < 0.05) and tender joints (r = 0.24, p = 0.021), patient (r = 0.4, p < 0.001) and physician-pain-visual analogue scale (VAS; r = 0.33, p < 0.001), patient global assessment (PGA)-VAS (r = 0.23, p = 0.025), physician-health assessment questionnaire (HAQ; r = 0.38, p = 0.011), Disease Activity Score (DAS)-44 (r = 0.25, p = 0.023) and Disease Activity in Psoriatic Arthritis (DAPSA; r = 0.31, p = 0.005). The instrument had excellent reliability in terms of internal consistency (Cronbach's alpha = 0.90) and stability (intraclass correlation = 0.98). Moderate agreement between PsA-Disk and PEST (Cohen's kappa = 0.46) was observed, while construct validity appeared appropriate [PsA + patients: PsA-Disk score (interquartile range; IQR) =71 (50-96); PsA-patients: PsA-Disk score (IQR)=50 (20-90); p < 0.001]. CONCLUSION: PsA-Disk may be considered a valid novel instrument aiding both dermatologists and rheumatologists in the rapid detection and assessment of musculoskeletal disease characteristics.

Hydroxyurea associated with concomitant occurrence of diffuse longitudinal melanonychia and multiple squamous cell carcinomas in an elderly subject.

BACKGROUND: Hydroxyurea is a cytostatic agent used to treat myeloproliferative disorders and long-term treatment is associated with mucocutaneous adverse events and nail hyperpigmentation. OBJECTIVE: The purpose of this study was to report the concomitant occurrence of multiple squamous cell carcinomas and diffuse nail hyperpigmentation associated with hydroxyurea treatment, and to describe a successful therapeutic approach using imiquimod 5%. CASE SUMMARY: We report the case of an 81-year-old white man (weight, 82 kg; height, 173 cm; photodamaged type II skin) affected with cirrhosis of the liver, chronic idiopathic myelofibrosis, and a 3-year history of longitudinal melanonychia and periungual hyperpigmentation. His current medication regimen was hydroxyurea (500 mg BID), iron (525 mg QD), and folic acid (15 mg QD) for the myeloproliferative disease and the associated anemia; spironolactone (25 mg BID) and furosemide (20 mg BID) for the complications of cirrhosis; allopurinol (100 mg QD) to treat gout; and theophylline (250 mg QD) for chronic bronchitis. The patient presented with several actinic keratoses, squamous cell carcinomas, and multiple keratoacanthomas, one of which was pigmented. Both the longitudinal melanonychia and the multiple skin cancers first appeared after approximately 6 months of hydroxyurea treatment. A correlation between dose and manifestation was investigated but none was found. Based on the Naranjo algorithm, the adverse reaction observed was probably related to the hydroxyurea treatment (score = 6); however, the hydroxyurea chemotherapy could not be discontinued because of the myeloproliferative disorder. Complete remission was observed after 6 to 10 weeks of imiquimod 5% (10 mg/cm of skin cancer) treatment. The patient completed a 10-month follow-up, maintaining a complete resolution of the treated skin lesions; however, the development of a painful hand ulcer, possibly associated with the hydroxyurea, and new skin cancers were observed at the last follow-up visit. CONCLUSIONS: We report this case of the concomitant appearance of multiple skin cancers and nail changes associated with hydroxyurea use. The progressive appearance of squamous epitheliomas and other cutaneous adverse events, such as the ulcer, suggests that alternative chemotherapies should be considered for the treatment of myeloproliferative diseases.

Effectiveness and safety of ustekinumab in naïve or TNF-inhibitors failure psoriatic arthritis patients: a 24-month prospective multicentric study.

The current prospective observational study aimed to evaluate the long-term (24 months), real-life effectiveness of ustekinumab in psoriatic arthritis (PsA). Consecutive patients with moderate-severe PsA and active psoriasis who begun ustekinumab treatment were evaluated prospectively (January 2015-March 2017). Clinimetric scores and biochemical values were assessed at baseline (T0), at 6 (T6), 12 (T12), and 24 (T24) months. Friedman test and generalized linear models were used to compare variables over time. Regression analysis to identify determinants of minimal disease activity (MDA) at T6 and of treatment discontinuation was conducted. Sixty-five patients (43.1% men; age 49.4 ± 11.6 years) were enrolled; ustekinumab was prescribed as a first (20%), second (33.8%), third (26.5%), fourth (15.4%), or fifth (4.6%) line biological therapy. Significant decrease in tender/swollen joints, Visual Analogue Scale of pain (VASp) and general health (VASgh), Disease Activity in PsA (DAPSA), Psoriasis Area Severity Index (PASI), Leeds Enthesitis Index (LEI), Health Assessment Questionnaire modified for spondyloarthritis (HAQ-S), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) was achieved. MDA was reached by 30.7, 47.0, and 34.0% of patients respectively at T6, T12, and T24. In multivariable models, mono-oligoarthritis was independently associated to MDA at T6 (OR 9.02; 95% CI 1.41, 57.71), while baseline CRP (OR 1.12; 95% CI 1.00, 1.26) and LEI (OR 0.50; 95% CI 0.25, 0.97) to ustekinumab discontinuation. More patients used disease-modifying antirheumatic drugs at T0 (35.3%) than at T24 (8.5%). Only nine episodes of infection and no serious adverse events were registered. In a real-life clinical setting, ustekinumab was safe and effective in PsA. Comedication tapering was often possible.

A 2-year observational study on treatment targets in psoriatic arthritis patients treated with TNF inhibitors.

The aim of this study was to evaluate clinical remission and MDA in PsA patients who started TNF-inhibitors (TNFi) treatment with a 2-year follow-up. Concomitant therapies as well as comorbidities were assessed. Level of concordance of clinimetric indices and the potential predictive factors of remission/MDA were also evaluated. Clinical and laboratory evaluations were prospectively performed in PsA patients at baseline (T0) and after 22 (T22), 54 (T54), and 102 (T102) weeks of treatment. Disease activity and disability were assessed using DAS28, CPDAI, DAPSA, MDA, and HAQ-SpA. The Pearson correlation coefficient, univariate, and multivariate binary logistic regression were performed. A total of 221 PsA patients were included. Cardiovascular diseases and metabolic syndrome (MetS) resulted as the most frequent comorbidities. Clinical remission was achieved by over a half of the patients during the follow-up. Use of concomitant therapies, such as csDMARDs and steroids, was significantly reduced during the follow-up. Agreement among indices of treatment targets by k-statistics was excellent for CPDAI and DAPSA and good for MDA and DAS28 or DAPSA. Female sex and MetS resulted as negative prognostic factors of clinical remission and MDA at all the time points. TNFi are highly effective in achieving treatment targets in PsA patients. DAS28, CPDAI, DAPSA, and MDA show a good agreement. Female sex and MetS are associated with a lower probability to achieve remission in PsA patients.

S100A8/A9 in psoriatic plaques from patients with psoriatic arthritis.

OBJECTIVE: To evaluate levels of the calcium-binding proteins S100A8 and S100A9 in the skin of patients with psoriatic arthritis. METHODS: Skin punch biopsies were obtained from patients with psoriatic arthritis and healthy control subjects. S100A8/A9 were semiquantified via immunohistochemistry and semiquantitative polymerase chain reaction. RESULTS: The study included biopsies from nine patients with psoriatic arthritis and nine control subjects. S100A8 and S100A9 were present at visibly higher levels in psoriatic plaques compared with normal skin samples. S100A8 and S100A9 RNA levels were significantly higher in the peripheral region of plaques compared with the central region. CONCLUSION: Both S100A8 and S100A9 may represent good therapeutic targets in psoriasis and psoriatic arthritis.

Long-term treatment with adalimumab in psoriatic arthritis: serum adalimumab concentration, immunogenicity and the link with clinical response.

OBJECTIVES: An observational study to evaluate the relationship between serum concentrations of adalimumab and disease activity in patients receiving long-term adalimumab treatment for psoriatic arthritis. METHODS: Serum adalimumab and adalimumab antidrug antibodies were quantified by enzyme linked immunosorbent assay. Disease activity was assessed using Disease Activity Score (44 joint measures). Serum C-reactive protein was quantified using standard methods. RESULTS: A total of 30 patients were recruited. There were significant inverse correlations between serum adalimumab concentration and serum C-reactive protein (CRP) concentration [r = -0.43], the number of tender joints (r = -0.4), and Disease Activity Score (DAS44)-CRP (r = -0.36). Mean serum adalimumab levels were significantly higher in patients with DAS44-CRP <1.6 than in patients with DAS44-CRP ≥1.6. CONCLUSIONS: Serum adalimumab could be an important tool that may improve the management of psoriatic arthritis in patients responding to long-term treatment.