A comparison of the safety and efficacy of tapinarof and roflumilast topical therapies in the management of mild-to-moderate plaque psoriasis.

INTRODUCTION: Psoriasis is an immune-mediated inflammatory skin disease. First-line topical treatments include steroids, calcineurin inhibitors, vitamin D analogs, and anthralin. Recently, novel topical therapeutics like tapinarof and roflumilast have emerged with unique anti-inflammatory mechanisms and promising efficacy profiles. MATERIALS AND METHODS: This review utilized PubMed, SCOPUS, and Web of Science databases to identify recent studies on tapinarof and roflumilast. Criteria focused on efficacy, safety profiles, and therapeutic roles in psoriasis treatment. RESULTS: Four primary literature articles were identified for tapinarof and five for roflumilast. Both drugs demonstrated strong efficacy with minimal adverse events in treating mild-to-moderate plaque psoriasis. Tapinarof showed more frequent but mild adverse effects, while roflumilast had less frequent but more severe side effects. DISCUSSION: Tapinarof and roflumilast offer once-daily dosing and successful treatment in restricted areas, potentially enhancing patient adherence. Cost remains a limiting factor, necessitating future comparative studies to evaluate the efficacy, safety, and cost-effectiveness between the two drugs. CONCLUSION: Tapinarof and roflumilast present promising topical treatments for psoriasis, showing efficacy and manageable safety profiles. Further research is crucial to fully elucidate their comparative benefits and drawbacks in clinical practice.

Early Inhibition of Phosphodiesterase 4B (PDE4B) Instills Cognitive Resilience in APPswe/PS1dE9 Mice.

Microglia activity can drive excessive synaptic loss during the prodromal phase of Alzheimer's disease (AD) and is associated with lowered cyclic adenosine monophosphate (cAMP) due to cAMP phosphodiesterase 4B (PDE4B). This study aimed to investigate whether long-term inhibition of PDE4B by A33 (3 mg/kg/day) can prevent synapse loss and its associated cognitive decline in APPswe/PS1dE9 mice. This model is characterized by a chimeric mouse/human APP with the Swedish mutation and human PSEN1 lacking exon 9 (dE9), both under the control of the mouse prion protein promoter. The effects on cognitive function of prolonged A33 treatment from 20 days to 4 months of age, was assessed at 7-8 months. PDE4B inhibition significantly improved both the working and spatial memory of APPswe/PSdE9 mice after treatment ended. At the cellular level, in vitro inhibition of PDE4B induced microglial filopodia formation, suggesting that regulation of PDE4B activity can counteract microglia activation. Further research is needed to investigate if this could prevent microglia from adopting their 'disease-associated microglia (DAM)' phenotype in vivo. These findings support the possibility that PDE4B is a potential target in combating AD pathology and that early intervention using A33 may be a promising treatment strategy for AD.

Crisaborole-Enthused Glycerosomal Gel for an Augmented Skin Permeation.

BACKGROUND: Crisaborole (CB), a boron-based compound, is the first topical PDE4 inhibitor to be approved by the US Food and Drug Administration (2016) for the treatment of Atopic Dermatitis. It is marketed as a 2% ointment (Eucrisa, Pfizer). However, CB is insoluble in water; therfore, CB glycersomes were formulated to enhance its permeation flux across the skin. OBJECTIVE: We developed a glycerosomal gel of CB and compared its in vitro release and permeation flux with the 2% conventional ointment. METHODS: Glycerosomes were prepared using thin film hydration method employing CB, soya phosphatidylcholine, and cholesterol. The formed film was further hydrated employing a mixture of phosphate buffer pH 7.4 /glycerin solution containing varying percentages (20,30, 40, and 50 %) of glycerol. The glycerosomes obtained were characterized by their size, polydispersity index (PDI), and Zeta potential. The entrapment efficiency of the optimized formulation (F1) was determined. The in vitro release of F1 was compared with its 2% conventional ointment. F1 was further incorporated into carbopol 934 P gel. The gel was characterized by pH, viscosity, spreadability, and drug content. The permeability flux of the glycerosomal gel was compared with its 2% conventional ointment. RESULTS: The optimized CB glycerosomes had a vesicle size of 137.5 ± 50.58 nm, PDI 0.342, and zeta potential -65.4 ± 6.75 mV. CB glycerosomal gel demonstrated a 2.13-fold enhancement in the permeation flux. CONCLUSION: It can thereby be concluded that glycerosomes can be an effective delivery system to enhance the penetration of CB across the skin.

An update on topical therapies for psoriasis.

PURPOSE OF REVIEW: Topical therapies are a mainstay of treatment for mild psoriasis and may be a useful adjunct in treatment of moderate-to-severe psoriasis. This review summarizes recent advances in topical therapies for psoriasis and currently available treatments. RECENT FINDINGS: Topical aryl hydrocarbon receptor modulators (tapinarof) and topical phosphodiesterase-4 inhibitors (roflumilast) have been proven effective in randomized controlled trials for psoriasis. Although topical JAK inhibitors have also been studied, none are currently licensed for treatment of psoriasis. Topical corticosteroids and vitamin D analogues remain the most commonly used and widely available topical treatments for psoriasis. Cost may limit use of novel topical agents. SUMMARY: Although the novel topical agents tapinarof and roflumilast are licensed for treatment of psoriasis by the FDA in the United States, they have not yet been licensed in Europe, and it remains to be seen whether they will be limited by cost.

Effects of oral roflumilast therapy on body weight and cardiometabolic parameters in patients with psoriasis - results from a randomized controlled trial (PSORRO).

BACKGROUND: Weight loss is reported with oral roflumilast, which is approved for chronic obstructive pulmonary disease (COPD). Recently, the drug has shown efficacy in psoriasis, a disease strongly linked to overweight/obesity. OBJECTIVE: To describe the effects of oral roflumilast on body weight and cardio-metabolic parameters in patients with psoriasis. METHODS: Posthoc analyses from the PSORRO study, where patients with moderate-to-severe plaque psoriasis were randomized 1:1 to oral roflumilast 500 µg once-daily or placebo for 12 weeks, followed by active, open-label treatment through week 24 in both groups. Changes in body weight, blood pressure, gastrointestinal symptoms, and laboratory tests were registered. No lifestyle or dietary interventions were applied. RESULTS: Forty-six patients were randomized. Baseline characteristics across groups were comparable; mean weight was 103.6 kg. In patients receiving roflumilast, median weight change was -2.6% and -4% at week 12 and 24, respectively. Corresponding numbers were 0.0% and 1.3% in patients initially allocated to placebo. Reduced appetite was more frequent with active therapy. No changes in blood pressure or laboratory tests were observed. LIMITATIONS: Posthoc analyses and low numbers. CONCLUSION: Oral roflumilast induced weight loss and reduced appetite, which support the growing evidence of roflumilast as an attractive treatment alternative for patients with psoriasis.

Long-term safety and effectiveness of roflumilast cream 0.3% in adults with chronic plaque psoriasis: A 52-week, phase 2, open-label trial.

BACKGROUND: Efficacy and/or safety profiles limit topical psoriasis treatments. OBJECTIVE: Evaluate long-term effects of once-daily roflumilast cream 0.3% in patients with psoriasis. METHODS: In this open-label phase 2 trial, adult patients (N = 332) with psoriasis who completed the phase 2b parent trial or were newly enrolled applied roflumilast once-daily for 52 weeks. Safety and effectiveness were assessed. RESULTS: Overall, 244 patients (73.5%) completed the trial; 13 patients (3.9%) discontinued due to adverse events (AEs) and 3 (0.9%) due to lack of efficacy. Twelve patients (3.6%) reported treatment-related AEs; none were serious. ≥97% of patients had no irritation. No tachyphylaxis was observed with 44.8% of the patients achieving Investigator Global Assessment (IGA) Clear or Almost Clear at Week 52. LIMITATIONS: Intertriginous-IGA and Psoriasis Area and Severity Index (PASI) were not evaluated in all patients. CONCLUSIONS: In this long-term trial, once-daily roflumilast cream was well-tolerated and efficacious up to 64 weeks in patients in the earlier trial, suggesting it is suitable for chronic treatment, including the face and intertriginous areas.

The Dosing Strategy to Improve Adherence to Roflumilast in Treatment for Chronic Obstructive Lung Disease: A Systemic Review and Meta-Analysis.

Background: The clinical efficacy of roflumilast, an oral phosphodiesterase-4 inhibitor, has been demonstrated in patients with severe chronic obstructive pulmonary disease (COPD). However, roflumilast has shown frequent adverse drug reactions (ADRs). This study was performed to investigate the dosing strategy that will improve adherence to roflumilast in COPD. Methods: We conducted a systematic review and meta-analysis using PubMed, Embase, and Cochrane Central Register. The dosing strategy for roflumilast was classified into a dose-escalation group and a low-dose group. We investigated clinical outcomes according to dosing strategy. Results: Five clinical trials involving 2424 patients were included. Both the dose-escalation and the low-dose groups showed a decrease in discontinuation rate compared to the standard dosing group for roflumilast (risk ratio [RR], 0.81; 95% confidence interval [CI], 0.67-0.97; P = 0.02 and RR, 0.62; 95% CI, 0.48-0.80; P < 0.01, respectively). In the two strategies, the pooled proportions of discontinuation were 27.9% and 11.7%, respectively. Although the pooled proportion of any ADR was not statistically decreased in the two strategies, diarrhea was significantly reduced in the low-dose group compared to the standard group (RR, 0.58; 95% CI, 0.42-0.82; P < 0.01). The pooled incidence of acute exacerbations was similar between the low-dose and the standard groups (22.9% and 20.1%, respectively; P = 0.27). Conclusion: Our findings show that the two alternative dosing strategies might have the benefit of improving adherence to roflumilast in COPD. Further large-scale trials are required to support our findings.

Efficacy and safety of apremilast in pediatric patients with moderate-to-severe plaque psoriasis: 16-week results from SPROUT, a randomized controlled trial.

BACKGROUND: Approved systemic treatment options are limited for pediatric patients with moderate to severe plaque psoriasis. OBJECTIVE: To assess the efficacy and safety of apremilast over 16 weeks in pediatric patients with plaque psoriasis. METHODS: SPROUT (NCT03701763) was a phase 3, multicenter, randomized, double-blind, placebo-controlled study of apremilast in patients aged 6-17 years with moderate-to-severe psoriasis (Psoriasis Area and Severity Index [PASI] ≥12, body surface area ≥10%, static Physician Global Assessment [sPGA] ≥3) inadequately controlled by/inappropriate for topical therapy. Patients were stratified by age group and randomized (2:1) to apremilast (20 or 30 mg BID based on weight) or placebo for 16 weeks, followed by apremilast extension to 52 weeks. RESULTS: Of 245 patients randomized (apremilast: 163; placebo: 82), 221 (90%) completed the double-blind phase (apremilast: 149; placebo: 72). Significantly more patients achieved sPGA response and ≥75% reduction in PASI with apremilast than placebo, regardless of baseline age, weight, or disease severity. No new safety signals were observed. LIMITATIONS: Sample size of subgroup analyses. CONCLUSIONS: Improvements in global disease activity and skin involvement were significantly greater in pediatric patients treated with apremilast versus placebo. Adverse events were consistent with the known apremilast safety profile.

Orismilast for the treatment of mild to severe hidradenitis suppurativa: Week 16 data from OSIRIS, a Phase 2a, open-label, single-centre, single-arm, dose-finding clinical trial.

BACKGROUND: Hidradenitis suppurativa (HS) is a disease with an unmet need for treatment. OBJECTIVE: To examine tolerability, safety and efficacy of oral phosphodiesterase-4 (PDE4) inhibitior orismilast 10-40 mg twice daily (BID) in HS. METHODS: A Phase 2a, single-arm, single-centre, open-label, 16-week trial in HS patients. Adjustments in maximal dose and titration were allowed, to improve tolerability, dividing the study population in two groups who completed and discontinued 16 weeks of treatment. Descriptive statistics were applied to efficacy data from patients who completed treatment and patients who discontinued treatment prematurely. A last-observation-carried-forward (LOCF) approach was used for patients who discontinued treatment. The primary endpoint was percent change in the total number of abscesses and nodules (AN-count) at Week 16, with the HS Clinical Response with a 50% reduction in the AN-count (HiSCR50) as key secondary endpoint. RESULTS: Of the 20 patients included, 9 completed 16 weeks of treatment and 11 discontinued treatment prematurely. The mean AN-count was reduced with 33.1% in patients who completed treatment and with 12.0% in patients who discontinued. HiSCR50 was achieved by 67.0% and 27.0% of patients who completed and discontinued treatment, respectively. Most adverse events were mild to moderate. CONCLUSIONS: Oral orismilast demonstrated a dose-dependent tolerability, with mild to moderate adverse effects. Further, the results of this exploratory trial indicate that orismilast may lead to clinical improvements in HS. However, larger trials with tolerable dose ranges are warranted. The Trial is registered at Clinicaltrials.gov (UNI50007201) and EudraCT.ema.europa.eu (2021-000049-42).

Efficacy and safety of crisaborole ointment in Chinese and Japanese patients aged ≥2 years with mild-to-moderate atopic dermatitis.

Atopic dermatitis is a chronic inflammatory skin disease with a significant impact on the overall wellbeing of patients and their families. Crisaborole ointment, 2%, is a nonsteroidal phosphodiesterase 4 inhibitor approved for the treatment of mild-to-moderate atopic dermatitis in multiple countries. However, in the key pivotal trials, a low proportion of the overall patient population was Asian, therefore the safety and efficacy of crisaborole in the Asian population with atopic dermatitis remains unclear. CrisADe CLEAR was a multicenter, randomized, double-blind, vehicle-controlled, phase 3 study (NCT04360187) to assess the efficacy and safety of crisaborole ointment in Chinese and Japanese patients aged ≥2 years with mild-to-moderate atopic dermatitis involving ≥5% treatable body surface area. Patients were randomly assigned 2:1 to receive crisaborole or vehicle twice daily for 28 days. The primary endpoint was percentage change from baseline in the Eczema Area and Severity Index total score at day 29. Additional endpoints were improvement and success per Investigator's Static Global Assessment score at day 29 and change from baseline on the Peak Pruritus Numerical Rating Scale at week 4. Safety was assessed using rates of treatment emergent adverse events, serious adverse events, and clinically significant changes in vital signs and clinical laboratory parameters. Crisaborole-treated patients showed a significantly greater reduction versus vehicle in percentage change from baseline in Eczema Area and Severity Index total score at day 29 (P = 0.0002). Response rates for achievement of Investigator's Static Global Assessment improvement and success at day 29 were significantly higher for patients treated with crisaborole versus vehicle (P = 0.0124 and P = 0.0078, respectively). Crisaborole-treated patients showed a significantly greater reduction versus vehicle in change from baseline on the Peak Pruritus Numerical Rating Scale at week 4 (P = 0.0009). No new safety signals were identified. Treatment with crisaborole was effective and well tolerated in Chinese and Japanese patients with mild-to-moderate atopic dermatitis.

Effect of Roflumilast Cream vs Vehicle Cream on Chronic Plaque Psoriasis: The DERMIS-1 and DERMIS-2 Randomized Clinical Trials.

Importance: Once-daily roflumilast cream, 0.3%, a potent phosphodiesterase 4 inhibitor, demonstrated efficacy and was well tolerated in a phase 2b trial of patients with psoriasis. Objective: To evaluate the efficacy of roflumilast cream, 0.3%, applied once daily for 8 weeks in 2 trials of patients with plaque psoriasis. Design, Setting, and Participants: Two phase 3, randomized, double-blind, controlled, multicenter trials (DERMIS-1 [trial 1; n = 439] and DERMIS-2 [trial 2; n = 442]) were conducted at 40 centers (trial 1) and 39 centers (trial 2) in the US and Canada between December 9, 2019, and November 16, 2020, and between December 9, 2019, and November 23, 2020, respectively. Patients aged 2 years or older with plaque psoriasis involving 2% to 20% of body surface area were enrolled. The dates of final follow-up were November 20, 2020, and November 23, 2020, for trial 1 and trial 2, respectively. Interventions: Patients were randomized 2:1 to receive roflumilast cream, 0.3% (trial 1: n = 286; trial 2: n = 290), or vehicle cream (trial 1: n = 153; trial 2: n = 152) once daily for 8 weeks. Main Outcomes and Measures: The primary efficacy end point was Investigator Global Assessment (IGA) success (clear or almost clear status plus ≥2-grade improvement from baseline [score range, 0-4]) at week 8, analyzed using a Cochran-Mantel-Haenszel test stratified by site, baseline IGA score, and intertriginous involvement. There were 9 secondary outcomes, including intertriginous IGA success, 75% reduction in Psoriasis Area and Severity Index (PASI) score, and Worst Itch Numeric Rating Scale score of 4 or higher at baseline achieving 4-point reduction (WI-NRS success) at week 8 (scale: 0 [no itch] to 10 [worst imaginable itch]; minimum clinically important difference, 4 points). Results: Among 881 participants (mean age, 47.5 years; 320 [36.3%] female), mean IGA scores in trial 1 were 2.9 [SD, 0.52] for roflumilast and 2.9 [SD, 0.45] for vehicle and in trial 2 were 2.9 [SD, 0.48] for roflumilast and 2.9 [SD, 0.47]) for vehicle. Statistically significantly greater percentages of roflumilast-treated patients than vehicle-treated patients had IGA success at week 8 (trial 1: 42.4% vs 6.1%; difference, 39.6% [95% CI, 32.3%-46.9%]; trial 2: 37.5% vs 6.9%; difference, 28.9% [95% CI, 20.8%-36.9%]; P < .001 for both). Of 9 secondary end points, statistically significant differences favoring roflumilast vs vehicle were observed for 8 in trial 1 and 9 in trial 2, including intertriginous IGA success (71.2% vs 13.8%; difference, 66.5% [95% CI, 47.1%-85.8%] and 68.1% vs 18.5%; difference, 51.6% [95% CI, 29.3%-73.8%]; P < .001 for both), 75% reduction in PASI score (41.6% vs 7.6%; difference, 36.1% [95% CI, 28.5%-43.8%] and 39.0% vs 5.3%; difference, 32.4% [95% CI, 24.9%-39.8%]; P < .001 for both), WI-NRS success (67.5% vs 26.8%; difference, 42.6% [95% CI, 31.3%-53.8%] and 69.4% vs 35.6%; difference, 30.2% [95% CI, 18.2%-42.2%]; P < .001 for both). The incidence of treatment-emergent adverse events was 25.2% with roflumilast vs 23.5% with vehicle in trial 1 and 25.9% with roflumilast vs 18.4% with vehicle in trial 2. The incidence of serious adverse events was 0.7% with roflumilast vs 0.7% with vehicle in trial 1 and 0% with roflumilast vs 0.7% with vehicle in trial 2. Conclusions and Relevance: Among patients with chronic plaque psoriasis, treatment with roflumilast cream, 0.3%, compared with vehicle cream resulted in better clinical status at 8 weeks. Further research is needed to assess efficacy compared with other active treatments and to assess longer-term efficacy and safety. Trial Registration: ClinicalTrials.gov Identifiers: NCT04211363, NCT04211389.

Role of Roflumilast Combined with ESHAP Chemotherapy in Relapsed/Refractory Patients with Diffuse Large B-Cell Lymphoma.

PURPOSE: There are unmet needs associated with the current treatment strategies for relapsed/refractory diffuse large B-cell lymphoma (DLBCL) due to the poor treatment outcomes of these strategies. Roflumilast, a selective phosphodiesterase-4 inhibitor used for treating chronic obstructive pulmonary disease, is effective against B-cell malignancy via phosphoinositide 3-kinase (PI3K)-activity suppression. We analyzed the effects of roflumilast combined with ESHAP (etoposide, cisplatin, methylprednisolone, and cytarabine) chemotherapy in experimental and clinical settings. MATERIALS AND METHODS: An in vitro study using lymphoma cell lines and a pilot study on relapsed/refractory DLBCL patients were conducted to investigate the effects and mechanism of the combination of roflumilast and chemotherapy. The complete response (CR), overall response rate (ORR), and 1-year progression-free survival (PFS) were analyzed. RESULTS: We found that roflumilast is efficient when combined with other chemotherapy drugs, especially cytarabine. Synergistic effects between these two drugs influence the translation of mammalian target of rapamycin and myeloid cell leukemia 1, resulting in apoptosis and inhibition of B-cell lymphoma proliferation. In clinical setting, the roflumilast group showed better rates of CR (46.2% vs. 34.6%), ORR (76.9% vs. 53.8%), and 1-year PFS (50.0% vs. 25.9%) compared with the control group, though not statistically significant. The roflumilast group showed a higher incidence of asthenia and gastrointestinal adverse events. However, grade 3 or 4 adverse events were similar in both groups. CONCLUSION: We found that roflumilast, when combined with ESHAP chemotherapy, for relapsed/refractory DLBCL was clinically active and well tolerated. This combined treatment was able to suppress PI3K activity, which is correlated with the degree of clinical response.

Inhaled Phosphodiesterase Inhibitors for the Treatment of Chronic Obstructive Pulmonary Disease.

Phosphodiesterase (PDE) 4 inhibitors prevent the metabolism of cyclic adenosine monophosphate, thereby reducing inflammation. Inhaled PDE4 inhibitors aim to restrict systemic drug exposure to enhance the potential for clinical benefits (in the lungs) versus adverse events (systemically). The orally administered PDE4 inhibitor roflumilast reduces exacerbation rates in the subgroup of chronic obstructive pulmonary disease patients with a history of exacerbations and the presence of chronic bronchitis, but can cause PDE4 related adverse effects due to systemic exposure. CHF6001 is an inhaled PDE4 inhibitor, while inhaled ensifentrine is an inhibitor of both PDE3 and PDE4; antagonism of PDE3 facilitates smooth muscle relaxation and hence bronchodilation. These inhaled PDE inhibitors have both reported positive findings from early phase clinical trials, and have been well tolerated. Longer term trials are needed to firmly establish the clinical benefits of these drugs.

Pharmacokinetics and tolerability of apremilast in healthy Korean adult men.

We performed a two-part study to evaluate the pharmacokinetics, safety, and tolerability of oral apremilast, a phosphodiesterase 4 inhibitor indicated for the treatment of psoriasis, in healthy Korean adult men. In part 1, there were 12 subjects who randomly received a single oral dose of apremilast at 20, 30, or 40 mg in each of 3 periods in a crossover fashion. In part 2, there were 16 subjects who randomly received 30 mg of apremilast or its matching placebo in a ratio of 3:1 twice daily for 14 days. Apremilast was rapidly absorbed (maximum concentration: ~2-3 h postdose), and eliminated according to a monoexponential pattern with a terminal-phase elimination half-life of 8-9 h. The exposure to apremilast increased in a dose-proportional manner and accumulation was 1.6-fold at steady-state. Apremilast was well-tolerated after a single oral administration and multiple oral administrations in Korean adult men; all of the treatment-emergent adverse events were mild and recovered without sequelae. In conclusion, apremilast was safe and well-tolerated in healthy Korean adult men when administered single oral doses of 20, 30, or 40 mg or when administered multiple oral doses of 30 mg b.i.d. for 14 days. Overall exposures increased in an approximate dose proportional manner in healthy Korean adult men.

Preliminary evidence for the phosphodiesterase type-4 inhibitor, roflumilast, in ameliorating cognitive flexibility deficits in patients with schizophrenia.

BACKGROUND: Cognitive flexibility deficits are present in patients with schizophrenia and are strong predictors of functional outcome but, as yet, have no pharmacological treatments. AIMS: The purpose of this study was to investigate whether the phosphodiesterase type-4 inhibitor, roflumilast, can improve cognitive flexibility performance and functional brain activity in patients with schizophrenia. METHODS: This was a within-subject, randomised, double-blind, placebo-controlled, three-period crossover study using a version of the Intradimensional/Extradimensional (ID/ED) task, optimised for functional magnetic resonance imaging (fMRI), in 10 patients with schizophrenia who were scanned after receiving placebo, 100 µg or 250 µg roflumilast for 8 consecutive days. Data from an additional fMRI ID/ED study of 18 healthy participants on placebo was included to contextualise the schizophrenia-related performance and activations. The fMRI analyses included a priori driven region of interest (ROI) analysis of the dorsal frontoparietal attention network. RESULTS: Patients on placebo demonstrated broad deficits in task performance compared to the healthy comparison group, accompanied by preserved network activity for solution search, but reduced activity in left ventrolateral prefrontal cortex (VLPFC) and posterior parietal cortex for attentional set-shifting and reduced activity in left dorsolateral prefrontal cortex (DLPFC) for reversal learning. These ROI deficits were ameliorated by 250 µg roflumilast, whereas during solution search 100 µg roflumilast reduced activity in the left orbitofrontal cortex, right DLPFC and bilateral PPC, which was associated with an improvement in formation of attentional sets. CONCLUSIONS: The results suggest roflumilast has dose-dependent cognitive enhancing effects on the ID/ED task in patients with schizophrenia, and provides sufficient support for larger studies to test roflumilast's role in improving cognitive flexibility deficits in this clinical population.