Vinod Chandran, MBBS, MD, DM, PhD

Several important studies on psoriatic arthritis (PsA) were published in the month of May 2021. Although, 50% of patients with PsA are women, many of them being in the child-beaing age, few studies have investigated pregnancy outcomes in women with psoriatic disease. Xie et al, report the results of their systematic review and meta-analysis of observational studies evaluating the impact of psoriasis and PsA on pregnancy outcomes. They retrieved 16 articles that met their study criteria. They demonstrate that pregnant women with psoriatic disease have significantly higher risk of adverse maternal outcomes (caesarean delivery, preterm birth, (pre)eclampsia, gestational diabetes, or gestational hypertension) compared with general population. However, no increased risk of fetal complications was observed. The authors recommend close monitoring of the mothers’ clinical status before and during pregnancy.

Despite availability of multiple targeted therapies, only about 60% of patients achieve a meaningful response to therapy in randomized trials and only a quarter of patients achieve a state of minimal disease activity. The assessment of musculoskeletal inflammation is heavily dependent on assessment of tender and swollen joints. However, whether tender or swollen joints, especially tender joints, truly reflect joint inflammation is a matter of debate. Felbo et al investigated the association between clinical joint tenderness and intra- and periarticular inflammation as assessed by ultrasound and magnetic resonance imaging (MRI) in patients with active PsA. They found that tender joints poorly reflect intra- and periarticular inflammation assessed by imaging. The association between swollen joints and ultrasound and MRI assessed inflammation was stronger but still only low-to-moderate. The agreement between joint tenderness and imaging assessed inflammation was even weaker in patients with high overall pain scores, high disability scores, or nonerosive disease. Therefore, it is recommended that imaging be used to supplement clinical examination in patients with PsA and high overall pain, disability, and/or nonerosive disease.

With regard to PsA treatment, Rahman et al reported the pooled safety results through one year of two phase 3 trials with guselkumab in PsA. This drug inhibits IL-23, has proven efficacy in PsA and psoriasis, and was recently approved for the treatment of PsA. No active tuberculosis, opportunistic infections, or inflammatory bowel disease, and low rates of malignancy and major adverse cardiovascular events, were observed in guselkumab-treated patients. In another study, using data from 2 large US claims databases, MarketScan and Optum’s De-identified Clinformatics® Data Mart, Jin et al demonstrated that other biologics and apremilast were associated with 1.4- to 3-times higher risk of hospitalized serious infections in patients with psoriatic disease when compared with ustekinumab. Ustekinumab is a biologic agent that inhibits IL-12 and IL-23 and is approved for the treatment of psoriasis, PsA, and ulcerative colitis. The two studies speak to the safety of targeting IL-23 with biologics in psoriatic disease.

Finally, an exploratory, proof-of-concept study explored whether fecal microbiota transplantation (FMT) improves the signs and symptoms of PsA. Kragsnaes et al conducted a double-blind, parallel-group, placebo-controlled, superiority trial, randomly allocating adults with active PsA despite ongoing treatment with methotrexate to one gastroscopic-guided FMT (15 patients) or sham transplantation (16 patients) into the duodenum. Surprisingly, treatment failure occurred more frequently in the FMT group than in the sham group (9 [60%] vs 3 [19%]; risk ratio, 3.20; 95% CI 1.06 to 9.62; P = 0.018). Improvement in HAQ-DI favoured sham treatment. There was no difference in the proportion of ACR20 responders between groups. No serious adverse events were observed. This study highlights that such studies are feasible but indicates that such interventions may not provide significant benefit. Further investigations including careful selection of donors, patients and concomitant therapy is required.

Several important studies on psoriatic arthritis (PsA) were published in the month of May 2021. Although, 50% of patients with PsA are women, many of them being in the child-beaing age, few studies have investigated pregnancy outcomes in women with psoriatic disease. Xie et al, report the results of their systematic review and meta-analysis of observational studies evaluating the impact of psoriasis and PsA on pregnancy outcomes. They retrieved 16 articles that met their study criteria. They demonstrate that pregnant women with psoriatic disease have significantly higher risk of adverse maternal outcomes (caesarean delivery, preterm birth, (pre)eclampsia, gestational diabetes, or gestational hypertension) compared with general population. However, no increased risk of fetal complications was observed. The authors recommend close monitoring of the mothers’ clinical status before and during pregnancy.

Despite availability of multiple targeted therapies, only about 60% of patients achieve a meaningful response to therapy in randomized trials and only a quarter of patients achieve a state of minimal disease activity. The assessment of musculoskeletal inflammation is heavily dependent on assessment of tender and swollen joints. However, whether tender or swollen joints, especially tender joints, truly reflect joint inflammation is a matter of debate. Felbo et al investigated the association between clinical joint tenderness and intra- and periarticular inflammation as assessed by ultrasound and magnetic resonance imaging (MRI) in patients with active PsA. They found that tender joints poorly reflect intra- and periarticular inflammation assessed by imaging. The association between swollen joints and ultrasound and MRI assessed inflammation was stronger but still only low-to-moderate. The agreement between joint tenderness and imaging assessed inflammation was even weaker in patients with high overall pain scores, high disability scores, or nonerosive disease. Therefore, it is recommended that imaging be used to supplement clinical examination in patients with PsA and high overall pain, disability, and/or nonerosive disease.

With regard to PsA treatment, Rahman et al reported the pooled safety results through one year of two phase 3 trials with guselkumab in PsA. This drug inhibits IL-23, has proven efficacy in PsA and psoriasis, and was recently approved for the treatment of PsA. No active tuberculosis, opportunistic infections, or inflammatory bowel disease, and low rates of malignancy and major adverse cardiovascular events, were observed in guselkumab-treated patients. In another study, using data from 2 large US claims databases, MarketScan and Optum’s De-identified Clinformatics® Data Mart, Jin et al demonstrated that other biologics and apremilast were associated with 1.4- to 3-times higher risk of hospitalized serious infections in patients with psoriatic disease when compared with ustekinumab. Ustekinumab is a biologic agent that inhibits IL-12 and IL-23 and is approved for the treatment of psoriasis, PsA, and ulcerative colitis. The two studies speak to the safety of targeting IL-23 with biologics in psoriatic disease.

Finally, an exploratory, proof-of-concept study explored whether fecal microbiota transplantation (FMT) improves the signs and symptoms of PsA. Kragsnaes et al conducted a double-blind, parallel-group, placebo-controlled, superiority trial, randomly allocating adults with active PsA despite ongoing treatment with methotrexate to one gastroscopic-guided FMT (15 patients) or sham transplantation (16 patients) into the duodenum. Surprisingly, treatment failure occurred more frequently in the FMT group than in the sham group (9 [60%] vs 3 [19%]; risk ratio, 3.20; 95% CI 1.06 to 9.62; P = 0.018). Improvement in HAQ-DI favoured sham treatment. There was no difference in the proportion of ACR20 responders between groups. No serious adverse events were observed. This study highlights that such studies are feasible but indicates that such interventions may not provide significant benefit. Further investigations including careful selection of donors, patients and concomitant therapy is required.

Several important studies on psoriatic arthritis (PsA) were published in the month of May 2021. Although, 50% of patients with PsA are women, many of them being in the child-beaing age, few studies have investigated pregnancy outcomes in women with psoriatic disease. Xie et al, report the results of their systematic review and meta-analysis of observational studies evaluating the impact of psoriasis and PsA on pregnancy outcomes. They retrieved 16 articles that met their study criteria. They demonstrate that pregnant women with psoriatic disease have significantly higher risk of adverse maternal outcomes (caesarean delivery, preterm birth, (pre)eclampsia, gestational diabetes, or gestational hypertension) compared with general population. However, no increased risk of fetal complications was observed. The authors recommend close monitoring of the mothers’ clinical status before and during pregnancy.

Despite availability of multiple targeted therapies, only about 60% of patients achieve a meaningful response to therapy in randomized trials and only a quarter of patients achieve a state of minimal disease activity. The assessment of musculoskeletal inflammation is heavily dependent on assessment of tender and swollen joints. However, whether tender or swollen joints, especially tender joints, truly reflect joint inflammation is a matter of debate. Felbo et al investigated the association between clinical joint tenderness and intra- and periarticular inflammation as assessed by ultrasound and magnetic resonance imaging (MRI) in patients with active PsA. They found that tender joints poorly reflect intra- and periarticular inflammation assessed by imaging. The association between swollen joints and ultrasound and MRI assessed inflammation was stronger but still only low-to-moderate. The agreement between joint tenderness and imaging assessed inflammation was even weaker in patients with high overall pain scores, high disability scores, or nonerosive disease. Therefore, it is recommended that imaging be used to supplement clinical examination in patients with PsA and high overall pain, disability, and/or nonerosive disease.

With regard to PsA treatment, Rahman et al reported the pooled safety results through one year of two phase 3 trials with guselkumab in PsA. This drug inhibits IL-23, has proven efficacy in PsA and psoriasis, and was recently approved for the treatment of PsA. No active tuberculosis, opportunistic infections, or inflammatory bowel disease, and low rates of malignancy and major adverse cardiovascular events, were observed in guselkumab-treated patients. In another study, using data from 2 large US claims databases, MarketScan and Optum’s De-identified Clinformatics® Data Mart, Jin et al demonstrated that other biologics and apremilast were associated with 1.4- to 3-times higher risk of hospitalized serious infections in patients with psoriatic disease when compared with ustekinumab. Ustekinumab is a biologic agent that inhibits IL-12 and IL-23 and is approved for the treatment of psoriasis, PsA, and ulcerative colitis. The two studies speak to the safety of targeting IL-23 with biologics in psoriatic disease.

Finally, an exploratory, proof-of-concept study explored whether fecal microbiota transplantation (FMT) improves the signs and symptoms of PsA. Kragsnaes et al conducted a double-blind, parallel-group, placebo-controlled, superiority trial, randomly allocating adults with active PsA despite ongoing treatment with methotrexate to one gastroscopic-guided FMT (15 patients) or sham transplantation (16 patients) into the duodenum. Surprisingly, treatment failure occurred more frequently in the FMT group than in the sham group (9 [60%] vs 3 [19%]; risk ratio, 3.20; 95% CI 1.06 to 9.62; P = 0.018). Improvement in HAQ-DI favoured sham treatment. There was no difference in the proportion of ACR20 responders between groups. No serious adverse events were observed. This study highlights that such studies are feasible but indicates that such interventions may not provide significant benefit. Further investigations including careful selection of donors, patients and concomitant therapy is required.

Although PsA affects men and women equally, the impact of the disease is often worse in women. In a large study from the Netherlands, in which 855 patients were carefully evaluated and follow up, Mulder MLM et al show that both subjective and objective measures of disease activity is more severe in women than men. The PsA Disease Activity Score, a validated composite measure of PsA disease activity, was also higher in women than men. The impact of disease on quality of life and function was significantly more in women and they were less often meeting treatment target. Further research into the impact of sex and gender in PsA is warranted and sex/gender-specific measures for managing PsA is required.

Janus kinase inhibitors (JAKi) are important new molecules increasingly being used in the management of inflammatory diseases. Tofacitinib is already available for the treatment of PsA. McInnes IB et al published results on the efficacy of upadacitinib, a more selective JAK1i already approved for treatment of RA, in treating PsA. In this phase 3 trial involving 1,704 patients with PsA who had an inadequate response to at least 1 nonbiologic disease-modifying antirheumatic drugs, the proportion of patients achieving at least 20% improvement in American College of Rheumatology (ACR20) response was significantly higher with upadacitinib 15 mg (70.6%) and 30 mg (78.5%) than with placebo (36.2%; P less than .001). Upadacitinib 15mg was found to have comparable efficacy as adalimumab (ACR20 65.0%), a well-established anti-TNF agent. However, adverse events were more frequent with upadacitinib.

Adverse events when on treatment with JAKi have recently come into sharp focus. Reassuringly, results from the OPAL Balance study, a 36-month, long-term extension phase 3 study involving 686 adult patients with active PsA on treatment with tofacitinib confirmed the long-term safety and efficacy of tofacitinib in patients with PsA. Nash P et al reported 1 instance of mortality occurred in tofacitinib group during the risk period (incidence, 0.1 patients with events [95% confidence interval, 0.0-0.3] per 100 person-years). The incidences of adverse events for herpes zoster, serious infections, opportunistic infections, adjudicated malignancies, and major adverse cardiovascular events were consistent with previous reports. However, given the reports of higher adverse events with tofacitinib compared to anti-TNF drugs in high-risk rheumatoid arthritis patients, more data is required to fully understand the risk profile of JAKi in patients with immune-mediated inflammatory diseases, including PsA.

With several drugs currently available to treat PsA and the paucity of head-to-head trials between them, choosing the most efficacious drug for treating patients with PsA has become challenging. To address this issue a network meta-analysis of 26 phase 3, randomized controlled trials that evaluated 13 targeted therapies among adults with active PsA was conducted. In a study sponsored by Janssen, Mease PJ et al report that guselkumab 100 mg every 8 weeks and every 4 weeks were comparable to anti IL-17A and subcutaneous anti-TNF agents for achieving ACR20 response. Guselkumab showed better Psoriasis Area Severity Index 90 and 75 responses than most of the other agents. The results indicate that guselkumab is as effective as other established agents in treating PsA, but formal head-to-head clinical trials will provide better evidence of relative efficacy and safety.

Although PsA affects men and women equally, the impact of the disease is often worse in women. In a large study from the Netherlands, in which 855 patients were carefully evaluated and follow up, Mulder MLM et al show that both subjective and objective measures of disease activity is more severe in women than men. The PsA Disease Activity Score, a validated composite measure of PsA disease activity, was also higher in women than men. The impact of disease on quality of life and function was significantly more in women and they were less often meeting treatment target. Further research into the impact of sex and gender in PsA is warranted and sex/gender-specific measures for managing PsA is required.

Janus kinase inhibitors (JAKi) are important new molecules increasingly being used in the management of inflammatory diseases. Tofacitinib is already available for the treatment of PsA. McInnes IB et al published results on the efficacy of upadacitinib, a more selective JAK1i already approved for treatment of RA, in treating PsA. In this phase 3 trial involving 1,704 patients with PsA who had an inadequate response to at least 1 nonbiologic disease-modifying antirheumatic drugs, the proportion of patients achieving at least 20% improvement in American College of Rheumatology (ACR20) response was significantly higher with upadacitinib 15 mg (70.6%) and 30 mg (78.5%) than with placebo (36.2%; P less than .001). Upadacitinib 15mg was found to have comparable efficacy as adalimumab (ACR20 65.0%), a well-established anti-TNF agent. However, adverse events were more frequent with upadacitinib.

Adverse events when on treatment with JAKi have recently come into sharp focus. Reassuringly, results from the OPAL Balance study, a 36-month, long-term extension phase 3 study involving 686 adult patients with active PsA on treatment with tofacitinib confirmed the long-term safety and efficacy of tofacitinib in patients with PsA. Nash P et al reported 1 instance of mortality occurred in tofacitinib group during the risk period (incidence, 0.1 patients with events [95% confidence interval, 0.0-0.3] per 100 person-years). The incidences of adverse events for herpes zoster, serious infections, opportunistic infections, adjudicated malignancies, and major adverse cardiovascular events were consistent with previous reports. However, given the reports of higher adverse events with tofacitinib compared to anti-TNF drugs in high-risk rheumatoid arthritis patients, more data is required to fully understand the risk profile of JAKi in patients with immune-mediated inflammatory diseases, including PsA.

With several drugs currently available to treat PsA and the paucity of head-to-head trials between them, choosing the most efficacious drug for treating patients with PsA has become challenging. To address this issue a network meta-analysis of 26 phase 3, randomized controlled trials that evaluated 13 targeted therapies among adults with active PsA was conducted. In a study sponsored by Janssen, Mease PJ et al report that guselkumab 100 mg every 8 weeks and every 4 weeks were comparable to anti IL-17A and subcutaneous anti-TNF agents for achieving ACR20 response. Guselkumab showed better Psoriasis Area Severity Index 90 and 75 responses than most of the other agents. The results indicate that guselkumab is as effective as other established agents in treating PsA, but formal head-to-head clinical trials will provide better evidence of relative efficacy and safety.

Although PsA affects men and women equally, the impact of the disease is often worse in women. In a large study from the Netherlands, in which 855 patients were carefully evaluated and follow up, Mulder MLM et al show that both subjective and objective measures of disease activity is more severe in women than men. The PsA Disease Activity Score, a validated composite measure of PsA disease activity, was also higher in women than men. The impact of disease on quality of life and function was significantly more in women and they were less often meeting treatment target. Further research into the impact of sex and gender in PsA is warranted and sex/gender-specific measures for managing PsA is required.

Janus kinase inhibitors (JAKi) are important new molecules increasingly being used in the management of inflammatory diseases. Tofacitinib is already available for the treatment of PsA. McInnes IB et al published results on the efficacy of upadacitinib, a more selective JAK1i already approved for treatment of RA, in treating PsA. In this phase 3 trial involving 1,704 patients with PsA who had an inadequate response to at least 1 nonbiologic disease-modifying antirheumatic drugs, the proportion of patients achieving at least 20% improvement in American College of Rheumatology (ACR20) response was significantly higher with upadacitinib 15 mg (70.6%) and 30 mg (78.5%) than with placebo (36.2%; P less than .001). Upadacitinib 15mg was found to have comparable efficacy as adalimumab (ACR20 65.0%), a well-established anti-TNF agent. However, adverse events were more frequent with upadacitinib.

Adverse events when on treatment with JAKi have recently come into sharp focus. Reassuringly, results from the OPAL Balance study, a 36-month, long-term extension phase 3 study involving 686 adult patients with active PsA on treatment with tofacitinib confirmed the long-term safety and efficacy of tofacitinib in patients with PsA. Nash P et al reported 1 instance of mortality occurred in tofacitinib group during the risk period (incidence, 0.1 patients with events [95% confidence interval, 0.0-0.3] per 100 person-years). The incidences of adverse events for herpes zoster, serious infections, opportunistic infections, adjudicated malignancies, and major adverse cardiovascular events were consistent with previous reports. However, given the reports of higher adverse events with tofacitinib compared to anti-TNF drugs in high-risk rheumatoid arthritis patients, more data is required to fully understand the risk profile of JAKi in patients with immune-mediated inflammatory diseases, including PsA.

With several drugs currently available to treat PsA and the paucity of head-to-head trials between them, choosing the most efficacious drug for treating patients with PsA has become challenging. To address this issue a network meta-analysis of 26 phase 3, randomized controlled trials that evaluated 13 targeted therapies among adults with active PsA was conducted. In a study sponsored by Janssen, Mease PJ et al report that guselkumab 100 mg every 8 weeks and every 4 weeks were comparable to anti IL-17A and subcutaneous anti-TNF agents for achieving ACR20 response. Guselkumab showed better Psoriasis Area Severity Index 90 and 75 responses than most of the other agents. The results indicate that guselkumab is as effective as other established agents in treating PsA, but formal head-to-head clinical trials will provide better evidence of relative efficacy and safety.

Psoriatic arthritis may be associated with excess mortality risk but the current evidence to support excess mortality in psoriatic arthritis is inconclusive. Nevertheless, identifying risk factors for mortality in patients with psoriatic arthritis is important so that modifiable factors could be addressed. Vela et al investigated whether the cumulative pain experienced by psoriatic arthritis patients was associated with increased mortality. Using data from the Danish nationwide registry of biological therapies (DANBIO), the authors showed that although there was a significant association between pain intensity and mortality (odds ratio 1.06 (95%CI 1.02 to 1.10) per 5 VAS unit increase), no association was found when the analyses was adjusted for confounders including age, CRP, joint counts, HAQ score, treatment, and comorbidities. As expected, recent glucocorticoid use, chronic obstructive pulmonary disease, diabetes mellitus, cancer and cardiovascular disease were associated with excess mortality. The results indicate that mortality in psoriatic arthritis is primarily driven by associated comorbidities; holistic management of psoriatic disease should include management of associated comorbidities.

Comorbidities have a major impact on patients with psoriatic arthritis and influence a patient’s quality of life and function as well as treatment response. Neuropsychiatric comorbidities have been less studied in psoriatic arthritis. An intriguing study by Garcia et al indicate that cognitive impairment may be associated with psoriatic arthritis. In a small cross-sectional study, they demonstrated that patients with psoriatic arthritis score worse on the Montreal Cognitive Assessment (MoCA) tool compared to controls, with executive skills, naming, language, and abstraction being most affected. Further research is required to explore whether other comorbidities such as cerebrovascular disease, depression or sleep disturbances explain the cognitive impairment. Depression and anxiety are also associated with reduced likelihood of achieving remission or low disease activity state in psoriatic arthritis. In a study of 743 patients, Wong et al demonstrated that patients with depression or anxiety are less likely to achieve a state of sustained minimal disease activity. These studies once again highlight the management of comorbidities to achieve improved outcomes in patients with psoriatic arthritis.

New data also indicate efficacy of targeted therapy in psoriatic arthritis. In two phase 3 trials funded by LEO pharma, Mease et al report that brodalumab, an interleukin 17 receptor inhibitor that is already available for the treatment for psoriasis, is efficacious in the treatment of psoriatic arthritis. Although the trial was terminated early, pooled data from the two trials showed that higher proportions of patients on 140 mg and 210 mg of brodalumab achieved American College of Rheumatology (ACR)20 response at week 16 compared to placebo group (45.8% and 47.9%, respectively vs. 20.9%; P less than .0001).

There are limited data on treatment withdrawal in patients with psoriatic arthritis. Coates et al investigated whether continued treatment with ixekizumab, an interleukin 17A inhibitor was superior to withdrawing ixekizumab in maintaining minimal disease activity state in patents with psoriatic arthritis. They showed that more patients relapsed rapidly after ixekizumab was withdrawn compared to those continuing ixekizumab treatment. Importantly, >95% of patients who relapsed with treatment withdrawal re-achieved MDA on retreatment with ixekizumab within a median duration of 4.1 weeks. Thus, ixekizumab treatment is best maintained after a patient achieves a state of minimal disease activity. If the treatment needs to be interrupted (e.g., infection, surgery), most patients will re-achieve the state of minimal disease activity on retreatment.

Finally, research continues to demonstrate delayed diagnosis of psoriatic arthritis. Karmacharya et al showed that only 45% of patients receive a diagnosis of psoriatic arthritis by 2 years after symptom onset. This study from the population-based Rochester Epidemiology Project indicates that earlier age of onset of symptoms, the presence of higher body mass index and enthesitis are associated with diagnostic delay. Further education of health care providers and patients with psoriasis about psoriatic arthritis may help reduce diagnostic delay; delayed diagnosis leads to poorer long-term outcomes.

Psoriatic arthritis may be associated with excess mortality risk but the current evidence to support excess mortality in psoriatic arthritis is inconclusive. Nevertheless, identifying risk factors for mortality in patients with psoriatic arthritis is important so that modifiable factors could be addressed. Vela et al investigated whether the cumulative pain experienced by psoriatic arthritis patients was associated with increased mortality. Using data from the Danish nationwide registry of biological therapies (DANBIO), the authors showed that although there was a significant association between pain intensity and mortality (odds ratio 1.06 (95%CI 1.02 to 1.10) per 5 VAS unit increase), no association was found when the analyses was adjusted for confounders including age, CRP, joint counts, HAQ score, treatment, and comorbidities. As expected, recent glucocorticoid use, chronic obstructive pulmonary disease, diabetes mellitus, cancer and cardiovascular disease were associated with excess mortality. The results indicate that mortality in psoriatic arthritis is primarily driven by associated comorbidities; holistic management of psoriatic disease should include management of associated comorbidities.

Comorbidities have a major impact on patients with psoriatic arthritis and influence a patient’s quality of life and function as well as treatment response. Neuropsychiatric comorbidities have been less studied in psoriatic arthritis. An intriguing study by Garcia et al indicate that cognitive impairment may be associated with psoriatic arthritis. In a small cross-sectional study, they demonstrated that patients with psoriatic arthritis score worse on the Montreal Cognitive Assessment (MoCA) tool compared to controls, with executive skills, naming, language, and abstraction being most affected. Further research is required to explore whether other comorbidities such as cerebrovascular disease, depression or sleep disturbances explain the cognitive impairment. Depression and anxiety are also associated with reduced likelihood of achieving remission or low disease activity state in psoriatic arthritis. In a study of 743 patients, Wong et al demonstrated that patients with depression or anxiety are less likely to achieve a state of sustained minimal disease activity. These studies once again highlight the management of comorbidities to achieve improved outcomes in patients with psoriatic arthritis.

New data also indicate efficacy of targeted therapy in psoriatic arthritis. In two phase 3 trials funded by LEO pharma, Mease et al report that brodalumab, an interleukin 17 receptor inhibitor that is already available for the treatment for psoriasis, is efficacious in the treatment of psoriatic arthritis. Although the trial was terminated early, pooled data from the two trials showed that higher proportions of patients on 140 mg and 210 mg of brodalumab achieved American College of Rheumatology (ACR)20 response at week 16 compared to placebo group (45.8% and 47.9%, respectively vs. 20.9%; P less than .0001).

There are limited data on treatment withdrawal in patients with psoriatic arthritis. Coates et al investigated whether continued treatment with ixekizumab, an interleukin 17A inhibitor was superior to withdrawing ixekizumab in maintaining minimal disease activity state in patents with psoriatic arthritis. They showed that more patients relapsed rapidly after ixekizumab was withdrawn compared to those continuing ixekizumab treatment. Importantly, >95% of patients who relapsed with treatment withdrawal re-achieved MDA on retreatment with ixekizumab within a median duration of 4.1 weeks. Thus, ixekizumab treatment is best maintained after a patient achieves a state of minimal disease activity. If the treatment needs to be interrupted (e.g., infection, surgery), most patients will re-achieve the state of minimal disease activity on retreatment.

Finally, research continues to demonstrate delayed diagnosis of psoriatic arthritis. Karmacharya et al showed that only 45% of patients receive a diagnosis of psoriatic arthritis by 2 years after symptom onset. This study from the population-based Rochester Epidemiology Project indicates that earlier age of onset of symptoms, the presence of higher body mass index and enthesitis are associated with diagnostic delay. Further education of health care providers and patients with psoriasis about psoriatic arthritis may help reduce diagnostic delay; delayed diagnosis leads to poorer long-term outcomes.

Psoriatic arthritis may be associated with excess mortality risk but the current evidence to support excess mortality in psoriatic arthritis is inconclusive. Nevertheless, identifying risk factors for mortality in patients with psoriatic arthritis is important so that modifiable factors could be addressed. Vela et al investigated whether the cumulative pain experienced by psoriatic arthritis patients was associated with increased mortality. Using data from the Danish nationwide registry of biological therapies (DANBIO), the authors showed that although there was a significant association between pain intensity and mortality (odds ratio 1.06 (95%CI 1.02 to 1.10) per 5 VAS unit increase), no association was found when the analyses was adjusted for confounders including age, CRP, joint counts, HAQ score, treatment, and comorbidities. As expected, recent glucocorticoid use, chronic obstructive pulmonary disease, diabetes mellitus, cancer and cardiovascular disease were associated with excess mortality. The results indicate that mortality in psoriatic arthritis is primarily driven by associated comorbidities; holistic management of psoriatic disease should include management of associated comorbidities.

Comorbidities have a major impact on patients with psoriatic arthritis and influence a patient’s quality of life and function as well as treatment response. Neuropsychiatric comorbidities have been less studied in psoriatic arthritis. An intriguing study by Garcia et al indicate that cognitive impairment may be associated with psoriatic arthritis. In a small cross-sectional study, they demonstrated that patients with psoriatic arthritis score worse on the Montreal Cognitive Assessment (MoCA) tool compared to controls, with executive skills, naming, language, and abstraction being most affected. Further research is required to explore whether other comorbidities such as cerebrovascular disease, depression or sleep disturbances explain the cognitive impairment. Depression and anxiety are also associated with reduced likelihood of achieving remission or low disease activity state in psoriatic arthritis. In a study of 743 patients, Wong et al demonstrated that patients with depression or anxiety are less likely to achieve a state of sustained minimal disease activity. These studies once again highlight the management of comorbidities to achieve improved outcomes in patients with psoriatic arthritis.

New data also indicate efficacy of targeted therapy in psoriatic arthritis. In two phase 3 trials funded by LEO pharma, Mease et al report that brodalumab, an interleukin 17 receptor inhibitor that is already available for the treatment for psoriasis, is efficacious in the treatment of psoriatic arthritis. Although the trial was terminated early, pooled data from the two trials showed that higher proportions of patients on 140 mg and 210 mg of brodalumab achieved American College of Rheumatology (ACR)20 response at week 16 compared to placebo group (45.8% and 47.9%, respectively vs. 20.9%; P less than .0001).

There are limited data on treatment withdrawal in patients with psoriatic arthritis. Coates et al investigated whether continued treatment with ixekizumab, an interleukin 17A inhibitor was superior to withdrawing ixekizumab in maintaining minimal disease activity state in patents with psoriatic arthritis. They showed that more patients relapsed rapidly after ixekizumab was withdrawn compared to those continuing ixekizumab treatment. Importantly, >95% of patients who relapsed with treatment withdrawal re-achieved MDA on retreatment with ixekizumab within a median duration of 4.1 weeks. Thus, ixekizumab treatment is best maintained after a patient achieves a state of minimal disease activity. If the treatment needs to be interrupted (e.g., infection, surgery), most patients will re-achieve the state of minimal disease activity on retreatment.

Finally, research continues to demonstrate delayed diagnosis of psoriatic arthritis. Karmacharya et al showed that only 45% of patients receive a diagnosis of psoriatic arthritis by 2 years after symptom onset. This study from the population-based Rochester Epidemiology Project indicates that earlier age of onset of symptoms, the presence of higher body mass index and enthesitis are associated with diagnostic delay. Further education of health care providers and patients with psoriasis about psoriatic arthritis may help reduce diagnostic delay; delayed diagnosis leads to poorer long-term outcomes.