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Psoriasis: What is new in nonbiologic systemic therapy in the era of biologics?
Amrinder J Kanwar
Department of Dermatology, Venereology and Leprology, Postgraduate Institute of Medical Education & Research, Chandigarh, 160012
|How to cite this article:
Kanwar AJ, Yadav S, Dogra S. Psoriasis: What is new in nonbiologic systemic therapy in the era of biologics?. Indian J Dermatol Venereol Leprol 2010;76:622-633
AbstractPsoriasis is a common debilitating disease significantly affecting the quality of life of the patients. Majority of the psoriasis patients have mild disease which can be managed by topical therapies. Around 30% of the psoriasis patients require systemic therapy during the course of their disease. There is a vast array of drugs for the treatment. Methotrexate, cyclosporine and retinoids are the most commonly used conventional systemic drugs. Newer studies provide insight into their more effective and safer use and as combination therapy with biologics. In recent times, many new drugs with novel mechanisms of action other than biologics have been tried in psoriasis. In this article, we have reviewed the current developments and new found role of the conventional drugs as well as the newer nonbiologic systemic drugs in the treatment of psoriasis.
Psoriasis is a chronic, inflammatory, multisystem disease which chiefly affects the skin and joints. It is a common disorder affecting approximately 2-3% of the world population.  Exact etiopathogenesis of the disease has not been clearly understood despite immense research in this field. However, the common consensus among the researchers is that it is predominantly a T cell mediated disorder occurring in genetically susceptible individuals, influenced by environmental factors. 
Parallel to the fresh insight into the etiopathogenesis, there has been a vast expansion in the treatment armamentarium for psoriasis. Various modalities of treatment comprise of topical or systemic medications, photo (chemo) therapy, and an array of biologic agents. Systemic therapies are generally used in patients with severe plaque type disease (>10% body surface area [BSA] or > 10 psoriasis area and severity index [PASI]), generalized pustular psoriasis, psoriatic erythroderma, severe psoriatic arthritis (PsA) and in those who are refractory to topical therapy and phototherapy. Patients with limited disease but having significant physical or psychosocial disability can also be considered for systemic therapy. It is estimated that about 30% of the patients have moderate to severe disease necessitating systemic therapy.  Many patients with psoriasis are not satisfied with the treatment results, feel that they are undertreated and desire a more complete control of the disease.  Hence, the quest for effective and adequate systemic therapy for psoriasis continues.
In recent years, there has been an increasing trend for use of biologic agents in the treatment of psoriasis. Biologics constitute targeted molecules specifically meant to modulate the chronic inflammation in psoriasis. Five biologic agents including infliximab, etanercept, adalimumab, alefacept and efalizumab have been approved by the Food and Drug Administration (FDA) for use in psoriasis. Efalizumab has been withdrawn from the US market w.e.f 8 th June 2009 following reports of four cases of progressive multifocal leucoencephalopathy (PML) (three of whom died) in patients on long-term therapy with this drug. Many new biologics are in various phases of clinical trials. But these drugs have their own limitations like high cost, potential serious side effects, indicated in selected individuals, and more importantly, lack of long-term safety data.
Conventional systemic therapy and newer analogues continue to find use in majority of psoriasis patients because of the ease of administration, low cost and vast experience in their use. In this article, we will be reviewing various new developments in the use of conventional systemic therapies (excluding photochemotherapy) as well as the newer nonbiologic systemic drugs for the management of psoriasis.
Methotrexate (MTX) is a gold standard systemic drug even today.  Despite the insurgence of various biologic therapies, MTX still is the main stay of treatment either as monotherapy or in combination with other drugs. Traditionally, it was widely believed that its antiproliferative action (folate metabolism antagonism) is primarily helpful in psoriasis. However, results of recent in vitro studies suggest that MTX causes inhibition of 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) transformylase leading to accumulation of AICAR, which in turn causes increased tissue concentration of adenosine. Primarily, this increased tissue concentration of adenosine accounts for its anti-inflammatory properties leading to symptom alleviation in psoriasis. 
Although there are no established maximum or minimum dosages of MTX, weekly dosages usually range from 7.5 to 25 mg given orally or parenterally.  Most of the studies reported in literature have used MTX starting at lower doses (7.5 mg/week) and gradually escalating the dose according to the response. 
However, at some centers, it has been used at higher doses (0.4-0.5 mg/kg once weekly) to start, with excellent clinical efficacy and good safety profile.  Though there are no randomized studies comparing the two dosage schedules, starting with higher dose leads to faster control of the disease activity and shorter duration of therapy which may result in lesser cumulative dose of MTX. It is important to minimize the total cumulative dose of MTX while maintaining disease control and medication tolerance.
Intramuscular administration is helpful when there is gastrointestinal intolerance to oral dosing or if there are concerns regarding patient compliance. Subcutaneous injection is equally effective and can be self-administered at home. Braun et al. found that injectable MTX has higher efficacy and equal tolerability compared to oral route in rheumatoid arthritis patients. Similar study needs to be done in psoriasis patients also. There is a controversy regarding the utility of giving a test dose of MTX. American Academy of Dermatologists recommends a test dose in patients with decreased calculated glomerular filtration rate and those at risk of hematologic toxicity with MTX.  Repeat laboratory tests for hematologic effects should be done at approximately 7 days.
Utility of folic acid (FA) supplementation is also debatable. Its use is advocated to limit the toxicity of MTX on liver, blood cells and gastrointestinal tract but there is a concern that it might reduce the efficacy of MTX. Two recent studies by Salim et al. and Chladek et al. have reported significant reduction in the efficacy of MTX with FA supplementation. Prey et al. conducted a systematic review to find out the effect of FA and folinic acid supplementation on MTX associated toxicity and efficacy in inflammatory diseases. They concluded that the FA supplementation is an effective measure to reduce the hepatic adverse effects. Gastrointestinal side effects were also lesser in those who received FA but the difference from the control group was not statistically significant. Effect on the hematologic side effects could not be assessed due to the low incidence of these events. Also, the effect of FA supplementation on the effectiveness of MTX could not be analyzed as markers of activity used in each study were different.
In recent comparative efficacy studies, MTX was found to have slightly lower efficacy compared to cyclosporine A (CSA). , The drug has also been reported to be safe and effective in childhood psoriasis.  Recently, the efficacy of MTX has been compared with biologics in the treatment of psoriasis  In a double-blind, placebo-controlled study of MTX versus adalimumab, 250 patients were randomized into three subgroups receiving MTX or adalimumab or placebo. MTX was given in doses of 7.5 mg weekly, increased as needed to 25 mg per week. At week 16, PASI 75 was achieved by 19% in the placebo arm, 36% in the MTX group, and 80% in the adalimumab group. In addition, MTX has been used as a combination therapy with many biologic agents approved by FDA. The combination therapy increases the efficacy and decreases the dose of individual drug, thereby decreasing the side effects. Specific advantage of combining tumor necrosis factor inhibitors (infliximab) with MTX has been the suppression of neutralizing auto-antibodies formation. , The drug has been combined with etanercept, when the efficacy of etanercept monotherapy is insufficient.  Alefacept has been used with MTX for PsA patients mostly with good results. 
Recent reports suggest that the interplay of several factors leads to an increased risk of cardiovascular disease in psoriasis patients and is a leading cause of mortality in this group of patients.  Long-term MTX therapy promotes hyperhomocysteinemia and therefore may potentially aggravate the cardiovascular diseases.  But a recent study found MTX to have cardio protective effects and it is speculated that probably inflammation, which has a central role in atherogenesis, plaque instability, and thrombosis, is inhibited by MTX.  The study also concluded that low to moderate cumulative dose of MTX was more beneficial than the higher dose and concomitant use of FA had an added advantage in the prevention of cardiovascular disease.
Non-alcoholic steatohepatitis (NASH) has been reported more commonly in psoriasis patients.  This group of patients are at a higher risk of development of cirrhosis if treated with MTX. Updated guidelines on liver biopsy to assess MTX induced toxicity recommend that psoriasis patients should be divided into two groups based on the presence of risk factors for liver injury.  Low risk psoriasis patients need not undergo baseline biopsy and liver function tests should be done at regular intervals. Liver biopsy is done at a cumulative dose of 3.5-4 g or earlier if there are more than five persistent elevations in five of nine aspartate aminotransferase (AST) levels over a 12-month period or if there is a decline in serum albumin below the normal range with normal nutritional status in the setting of well-controlled disease.  In the high risk patients, baseline liver biopsy is done after giving MTX for 2-6 months and repeat biopsy is done after every 1-1.5 g of cumulative dose. 
There is a continued search for laboratory tests which could replace liver biopsy for detection of liver fibrosis. Two recent studies have found estimation of pro-collagen 3 N-terminal peptide (PIIINP) as a useful marker of liver damage and that liver biopsies could be entirely avoided if PIIINP levels remained stable. , PIIINP assay has a limitation that it is not organ specific and measures ongoing fibrogenesis only. There are various other direct and indirect markers of ongoing liver fibrosis, which have been investigated and found to have 90% sensitivity in chronic liver disease patients.  Different markers have been combined to calculate indices which have been applied for the detection of liver fibrosis with varying degrees of success. , Indirect markers of liver fibrosis include a2-macroglobulin, a2-globulin, g-globulin, apolipoprotein A1, g-glutamyltransferase and total bilirubin.  Direct markers of fibrosis in addition to PIIINP, include procollagen I, type IV collagen, laminin, hyaluronic acid (HA), tissue metalloproteinases and their inhibitors.  These markers need to be tested in large number of psoriasis patients to find their utility in the detection of MTX-induced liver fibrosis.
Recent (2009) American Academy of Dermatologists recommendations have modified the list of absolute and relative contraindications to be observed when prescribing MTX.  Besides pregnancy and lactation, alcoholic liver disease or other chronic liver disease, immunodeficiency syndromes, bone-marrow hypoplasia (leukopenia, thrombocytopenia, or significant anemia) and hypersensitivity to MTX are now considered as absolute contraindications for MTX. While relative contraindications include abnormalities in renal and liver functions, active infection, obesity, diabetes mellitus, concomitant use of hepatotoxic drugs, recent vaccination with a live vaccine, and unreliable patient. Recommendations in relation to pretreatment testing and tests for monitoring during MTX therapy continue to be the same.
Comparing MTX vis a vis biologics, it has main advantages of low cost, oral administration, established safety data and proven efficacy over more than last five decades.
CSA has the highest efficacy among all the nonbiologic systemic therapies. It is called the crisis drug as it is effective in cases resistant to other modalities and brings rapid control even in very severe cases. CSA is given in doses of 2.5-5 mg/kg/day. Many studies have shown that CSA, when used for 12-16 weeks, leads to a significant improvement in psoriasis in up to 80-90% of patients. ,, This drug has been found to be useful in the management of childhood psoriasis also. , A recent review of its use in children has suggested that the side effect profile is similar to that of adults. 
Main problems with CSA are drug-induced hypertension, renal side effects, increased incidence of malignancy and rebound flare after stopping the drug. Long-term therapy results in permanent renal scarring and loss of function. Patients who are treated with CSA for more than 2 years continuously have especially high risk of developing irreversible renal damage. To avoid this dreaded complication, CSA should be given in intermittent courses of maximum 12 weeks duration. ,, Another concern with CSA is the increased incidence of cutaneous squamous cell carcinomas (SCC) especially in patients who have previously received PUVA (psoralen + UV A) therapy. In a large (5-year follow up) cohort study evaluating more than 1200 subjects on long-term CSA, there was a sixfold increased risk of nonmelanoma skin cancers, especially SCC, in patients who had received additional PUVA therapy, whereas the incidence of internal malignancy was not found to be high as compared to the general population. 
After an initial observation of the improvement of psoriasis in one heart and three liver transplant recipients on tacrolimus, the drug was tested in severe recalcitrant psoriasis patients with good response. 
Subsequently, a double-blind, placebo-controlled study conducted by European FK 506 multicenter psoriasis study group reported 83% PASI reduction in 27 psoriasis patients at the end of 9 weeks. 
Newer calcineurin inhibitors including pimecrolimus and voclosporine, with higher efficacy and better side effect profile are increasingly being tried in psoriasis. Oral pimecrolimus was initially used by Rappersberger et al. with high clinical efficacy and good tolerability. Subsequently, in a large, double-blind, dose-finding study, pimecrolimus given in doses of 20 and 30 mg twice daily in psoriasis patients, caused a mean percentage reduction in PASI by 51.3% and 54% respectively at week 7 from the baseline.  The drug was well tolerated and there were no clinically relevant abnormalities in the laboratory parameters.
Voclosporine is a novel calcineurin inhibitor having higher affinity for calcineurin and faster clearance of its metabolites from the body, as compared to CSA. The drug has been found to be effective in psoriasis in phase II and III studies. , In phase II studies, PASI 75 response was achieved in 67% of cases receiving 1.5 mg/kg/day of voclosporine without much change in blood pressure or concentrations of lipids or triglycerides. In phase III dose-finding study, 451 plaque psoriasis patients received either voclosporine or placebo. At the end of 12 weeks, PASI 75 response was achieved in the voclosporine 0.2, 0.3, and 0.4 mg/kg groups by 16, 25, and 47% of patients, respectively, and in the placebo group by 4% of patients. Voclosporine with high efficacy comparable to CSA and better safety profile is a promising future therapy for psoriasis.
Retinoids are vitamin A derivatives, which modulate epidermal proliferation and differentiation, have immunomodulatory as well as anti-inflammatory properties. Acitretin, the active metabolite of etretinate, is the most commonly used oral retinoid for psoriasis. It is less effective compared to MTX and CSA as monotherapy and requires 3-6 months to achieve maximal response. It has been used in different doses in clinical trials and the results are largely dose dependent. 
Acitretin as monotherapy is particularly considered to be effective in exfoliative erythrodermic psoriasis and pustular psoriasis.  It has been extensively used in combination with ultraviolet B (UVB) or PUVA therapy for chronic plaque type psoriasis with enhanced efficacy, reduced treatment frequency, duration, and cumulative UV doses, resulting in a more effective, convenient, and safer treatment. 
Important advantages with this drug are chemoprevention against malignancy and that it is not immunosuppressive. Therefore, it is the drug of choice in human immunodeficiency virus (HIV) positive patients with psoriasis and is also used as combination therapy with biologics. 
Acitretin has significant adverse effects like teratogenic potential, hyperlipidemia, mucocutaneous side effects, diffuse idiopathic hyperostosis, liver toxicity, and pseudotumor cerebri-like symptoms. Women of childbearing age should use adequate contraception for at least 3 years after discontinuing the use of acitretin. Isotretinoin is an option in women of child bearing age as its elimination half life is short and adequate contraception should be maintained for at least 1 month after stopping the drug.
Newer generation retinoids (tazarotene) are increasingly being used for psoriasis because of their better pharmacokinetic properties and selectivity for the beta and gamma subtypes of retinoic acid receptors (RARs), resulting in targeted action on psoriatic keratinocytes, thereby minimizing the risk of adverse effects. The wash out period of tazarotene is short due to shorter half-life of 7-12 hours of its active metabolite, tazarotenic acid. Therefore, the contraception may only be necessary for a few days after the last dose. Tazarotene has been found to be an effective, safer and better tolerated oral retinoid for psoriasis patients in phase III studies.  Unlike other retinoids, it does not significantly increase the prevalence of hypertriglyceridemia, hypercholesterolemia, abnormal liver function test results, desquamation, eye dryness, or alopecia. This drug has been safely used for up to 52 weeks. 
Bexarotene is a synthetic retinoid X receptor (RXR)-selective retinoid. In phase II multicentric study, >50% improvement in modified PASI, plaque elevation, and physician′s global assessment was seen in 22, 52, and 36% of patients, respectively. 
Retinoids have several advantages over conventional systemic drugs like they are not immunosuppressive, there is no limitation of cumulative dose, and they cause no significant hepatic or renal toxicity. Therefore, these are good candidates for combination and maintenance therapy both with conventional systemic anti-psoriatic drugs as well as with the biologic agents.
Fumaric Acid Esters
Fumaric acid esters (FAE) are a mixture of dimethylfumarate (DMF) and monoethylfumarate salts commonly used in Northern Europe, particularly in Germany and the Netherlands, as the first line systemic treatment for chronic plaque psoriasis, with proven efficacy and low toxicity. It is given in doses of 120-720 mg (DMF) daily.
The mechanism of action of the drug is only partially understood. Lehmann et al. in an in vitro assay found that DMF and diethylfumarate are the active compounds and FAE mediates its immunomodulatory activity by the induction of the anti-inflammatory stress protein, heme oxygenase 1.
Balasubramaniam et al.  from United Kingdom reported good efficacy and safety of FAE, both as monotherapy and in combination therapy with CSA, acitretin, hydroxyurea and MTX. In another nonrandomized prospective cohort study, 80 patients with severe, recalcitrant, chronic plaque psoriasis received FAEs.  Of the total patients, 59% were on other concomitant oral anti-psoriatic agent. At 3 months, PASI 90 was achieved in 4%, PASI 75 in 8% and PASI 50 in 20% of cases. Side effects were reported by 74% of patients, resulting in cessation of FAE in 36% of cases. Most common side effects were diarrhea, abdominal pain and flushing, whereas lymphopenia occurred in 33% of patients.
Reich et al. analyzed the data of 984 patients who were treated with FAE for at least 24 months (mean duration 44 months). There was marked improvement in 67% after 6 months, 78% after 24 months, and 82% of patients after 36 months of therapy. Changes of laboratory parameters were usually insignificant.
Recent studies suggest that FAEs are effective as monotherapy and can be used in combination with other oral anti-psoriatic agents. Subjective side effects are mainly gastrointestinal and flushing. The drug does not affect the liver and renal functions significantly but lymphopenia is a common adverse effect which needs close monitoring.
Hydroxyurea is an antimetabolite which works by inhibiting DNA replication. Its efficacy in psoriasis is known for 30 years.  The drug has not been extensively used in psoriasis. There is a renewed interest in its use from India. Kumar et al. treated 31 patients of chronic plaque type disease with 1-1.5 g daily doses of hydroxyurea. Over half of the patients showed more than 70% reduction in PASI score. Sharma et al. used it in 34 psoriasis patients with similar results. Their three patients developed leukopenia requiring discontinuation of the drug.
In a recent comparative study of MTX and hydroxyurea, there was 77% and 49% reduction in the mean PASI score, respectively, at 12 weeks.  Gach et al. used hydroxyurea in combination with infliximab to treat a recalcitrant case of psoriasis.
Major adverse effect of hydroxyurea is bone marrow toxicity, whereas liver and renal toxicity are rare. It provides a useful cheap alternative for systemic treatment of psoriasis.
Mycophenolate mofetil (MMF) is a prodrug of mycophenolic acid. It is a lymphocyte selective immunosuppressive agent which acts by non-competitive inhibition of de novo purine synthesis due to inhibition of inosine monophosphate dehydrogenase enzyme. MMF was first used for psoriasis in 1998.  Subsequently, there are many reports suggesting the efficacy of MMF in psoriasis. ,
Beissert et al. carried out a prospective, multicenter, randomized trial comparing the efficacy of MMF with that of CSA for the treatment of chronic plaque-type psoriasis. After 12 weeks, CSA demonstrated a significantly superior efficacy compared to MMF but there was no difference in time to disease relapse, side effects, and psoriasis disability index.
Retinoic Acid Metabolism Blocking Agents:Liarozole,Talarozole(Rambazole)
The novel systemic all-trans retinoic acid metabolism blocking agents (RAMBA) act by blocking cytochrome P-450 dependent 4-hydroxylation of all-trans-retinoic acid (ATRA), modulating the intracellular levels of endogenous retinoids, leading to normalization of aberrant epithelial growth and differentiation. The plasma ATRA levels do not rise beyond physiologic levels.
RAMBA are retinoid mimetic drugs with a side effect profile similar to that of retinoids but of lower incidence. These drugs can be given more readily to women and children than retinoids as there is rapid clearance of the RAMBA unlike the available synthetic retinoids which may stay in the body for a long time.
Subsequently, talarozole has been used for psoriasis patients as this drug is a more selective inhibitor of the enzyme retinoic acid 4-hydroxylase, necessitating reduced dose and hence fewer side effects. Verfaille et al.  treated 19 patients of psoriasis with 1 mg talarozole, resulting in significant reduction in PASI in 8 weeks. Talarozole is in the phase II clinical trial stage. 
Leflunomide acts by inhibiting de novo pyrimidine synthesis. It is a disease-modifying antirheumatic drug which can be particularly beneficial for psoriasis patients with concurrent PsA. In a double blind, randomized, placebo-controlled trial of 182 patients of psoriasis and PsA, a PASI 75 response was achieved in 17% among leflunomide group versus 8% in the placebo group at 24 weeks.  PsA responded in 59% in leflunomide group versus 30% in placebo group. Patients were allowed concurrent use of low-dose systemic corticosteroids for the treatment of their PsA.
Adverse effects caused by leflunomide are gastrointestinal irritation, elevated liver enzymes, leukopenia, drug eruption, headache, increased risk of infections, and teratogenicity.  Adequate contraception should be maintained during therapy with leflunomide and additionally for 3 months in males and 2 years in females after stopping the drug.
Rapamycin inhibitors:Sirolimus and Everolimus
Sirolimus is similar in structure to CSA and tacrolimus but it is not a calcineurin inhibitor. Sirolimus binds to FK506 binding protein12 (FKBP12) and interrupts the cell cycle progression from G1 to the S phase, leading to the suppression of T-lymphocyte activation and proliferation. 
In a large multicenter study of 150 patients with severe chronic plaque psoriasis, oral sirolimus, CSA, and a combination of the two were assessed.  Comparable results were obtained in patients treated with CSA alone (5.0 mg/kg/day) and in those treated with subtherapeutic CSA (1.25 mg/kg/day) combined with sirolimus (3.0 mg/m 2 ). Sirolimus monotherapy was found to be ineffective. Sirolimus and CSA can be used as combination therapy limiting their cumulative toxicity. Sirolimus causes less nephrotoxicity, neurotoxicity, and hypertension compared to CSA or tacrolimus.
Everolimus is a semisynthetic, immunosuppressive and antiproliferative macrolide derived from sirolimus, with better pharmacokinetic properties. It has successfully been used in combination with subtherapeutic doses of CSA to treat a woman with severe psoriasis refractory to traditional therapies. 
Thiazolidinediones (TZD) are used as insulin sensitizers in type 2 diabetes mellitus. These drugs lower insulin resistance in peripheral tissues and reduce hepatic glucose output by binding to peroxisome proliferator-activated receptors (PPAR) gamma. Shafiq et al. undertook a double-blind, randomized, placebo-controlled study to test the efficacy of pioglitazone as monotherapy in psoriasis patients. Seventy patients with moderate to severe psoriasis received either pioglitazone 15 mg or pioglitazone 30 mg or placebo for 10 weeks. The percentage reduction in mean PASI scores was 21.6, 41.1 and 47.5% in the placebo, pioglitazone 15 mg, and 30 mg groups, respectively. There were no serious adverse events noted except for a fall in hemoglobin in one patient and elevation of liver enzymes in two patients.
Recently, pioglitazone and acitretin have been used in combination with higher efficacy compared to control group receiving acitretin alone.  Bongartz et al. used pioglitazone in 10 patients of PsA with a good response. Troglitazone efficacy in psoriasis has also been reported. , A recent study demonstrated that rosiglitazone is not more effective than placebo. 
In the recent times, there has been growing literature on the association between psoriasis and metabolic dysfunction, including insulin resistance, obesity, dyslipidemia, and cardiovascular diseases. TZD would help psoriasis patients additionally in fighting against these metabolic dysfunctions as they are insulin sensitizers and possess an array of beneficial effects including normalizing blood pressure, increasing high-density lipoprotein, and improving fibrinolysis. 
Azathioprine is an immunosuppressant used in the treatment of blistering disorders, atopic dermatitis and various inflammatory dermatoses. There are no randomized trials but few open label studies suggest its efficacy in psoriasis. ,
Azathioprine acts slowly requiring at least 6-8 weeks for the onset of action. Important adverse effects include myelosuppression, liver toxicity and gastrointestinal side effects. Thiopurine methyltransferase (TPMT) levels should be measured to guide dosing. 
Paclitaxel is a chemotherapeutic agent having antiproliferative, antiangiogenic, and anti-inflammatory properties. In a phase II pilot study involving 12 severe psoriasis patients, there was a dose-dependent response with decrease in PASI scores varying from 15% to 80% in different patients.  Two patients had hypersensitivity reactions, whereas none developed myelosuppression.
Nanoemulsion formulation of paclitaxel enhanced the peroral bioavailability of the drug in rats.  However, these newer formulations need evaluation in psoriasis patients to establish their efficacy as well as the safety.
Neovastat is extracted from shark cartilage by homogenization and ultrafiltration. It is vascular endothelial growth factor (VEGF) antagonist and has been shown to have anti-angiogenic and anti-inflammatory properties in an in vitro assay. 
Sauder et al.,  in a randomized phase I/II dose-comparison clinical trial involving 49 psoriasis patients, showed that patients receiving 60, 120, or 240 ml/day of neovastat showed statistically significant decrease in PASI score in 30.8, 41.7 and 50% of the patients, respectively. Nonserious drug-related adverse events affected the gastrointestinal system in 12 of 49 patients (primarily nausea, diarrhea, vomiting, flatulence, and constipation) and the skin and appendages in 4 of 49 patients (primarily acne and rash).
The antiangiogenic agent neovastat is a new therapeutic approach in the management of psoriasis but more extensive studies need to be done before the drug is approved for the treatment of psoriasis.
Most of the treatment modalities provide symptomatic relief and do not lead to permanent cure or long-term remission. Immunotherapy is under evaluation so as to produce immunomodulation and long-term remission. Immunotherapy probably works by inducing a transient Th1 response with compensatory Th2 response. After preliminary investigations, two intradermal injections of heat-killed suspension of Mycobacterium vaccae (M. vaccae) were given at 3 weeks interval to chronic plaque psoriasis patients.  Improvement in PASI score was seen in 19 of 21 patients and the improvement persisted for 6 months. A subsequent study supported its efficacy. 
Balagon et al. tested psoriasis vaccine (PVAC) which is a more potent derivative of M. vaccae. It contains heat-killed, delipidated, deglycolipidated M. vaccae. In an open trial, 65% patients showed more than 50% reduction in the PASI score at 12 weeks after the injections. In two subsequent studies investigating PVAC in psoriasis and PsA patients, it was found to be ineffective. ,
Mw (Mycobacterium w) vaccine has been tried in psoriasis patients in small studies. Rath et al. conducted a pilot study in which 24 patients received two injections of Mw vaccine at 3 weeks interval. In 4 months, 16.6% had marked improvement (>50% reduction), 62.5% had moderate improvement (25-50% reduction), and 16.6% showed no change (<25% reduction).
Subsequently, this vaccine was tested in 45 patients with mild to moderate plaque-type psoriasis.  In this study, results were not encouraging, with less than 40% patients showing mild to moderate improvement.
Another vaccine, psoraxine, which was originally developed to induce resistance against leishmaniasis, is still in experimental stages for psoriasis. 
Peptide-T is a synthetic octapeptide that shares a segment of the envelope glycoprotein (gp 120) of the HIV. Its use in a HIV negative patient of psoriasis with PsA was reported for the first time in 1989.  It is speculated that peptide-T acts by inhibition of interferon (IFN)-gamma production and induction of interleukin (IL)-10.  Marcusson et al. treated nine patients of recalcitrant and long-standing psoriasis with 2 mg peptide-T intravenous daily injections given for 28 days. Eight of them showed less than 50% improvement by day 28 and five patients had more than 50% improvement at 3 months. Limitations with peptides are that they exhibit poor absorption, get easily metabolized and are immunogenic.
Recently, synthetic analogues of natural product, amygdalin, were tested on human keratinocyte cultures and found to have effects similar to that of peptide-T.  These synthetic analogues need further exploration in psoriasis patients.
Tyrosine kinase inhibitors
There are individual reports of clinical improvement in psoriasis with tyrosine kinase inhibitors (TKI) when given to cancer patients.  SU-011248 is a VEGF receptor-tyrosine kinase inhibitor which has been tried in psoriasis.  Further prospective randomized control studies need to be done to prove their efficacy.
p38 Mitogen activated protein kinase inhibitor
Intracellular protein cascades such as mitogen activated protein kinases (MAPK) are involved in cell cycle kinetics. Novel p38 MAPK inhibitor, BMS-582949, is in phase II studies for inflammatory diseases including rheumatoid arthritis, psoriasis and atherosclerosis. 
Protein kinase C inhibitors
Protein kinase C (PKC) inhibitors block early T cell activation. AEB071 strongly and selectively inhibits the classical (a, b) and the novel theta (q)-PKC isoforms. In a recently published study, AEB071 was given orally to 32 patients with severe plaque psoriasis for 2 weeks.  There was a dose-dependent response, with PASI 75 achieved in 69% of the treatment group receiving 300 mg twice daily. Larger patient cohorts and longer treatment periods are required to establish its safety and efficacy in psoriasis.
The phosphodiesterases (PDE) are the enzymes which degrade second messenger molecules cAMP and cGMP. They have broad anti-inflammatory effects and therefore have been tried in psoriasis and atopic dermatitis. Dose-limiting side effects of PDE are nausea, diarrhea, vomiting and abdominal pain. In a pilot study, oral apremilast, a PDE-4 inhibitor, was given to 19 psoriasis patients. There was improvement in 73% of cases with mild adverse effects.  Further studies are warranted.
Nerve growth factor receptor blocker
Recent research supports the role of nerve growth factors (NGFs) and neurogenic inflammation in the pathogenesis of psoriasis.  Novel therapeutic agent K252a is a high-affinity NGF receptor blocker. It improved psoriatic plaques in severe combined immunodeficient mouse-human skin model of psoriasis. 
Treatment of psoriasis is still evolving. MTX, CSA and retinoids are well-established and time-tested drugs. In recent times, there has been vast expansion in the armamentarium of therapeutic agents for psoriasis as we have entered the exciting new era of biologic therapy. Long-term experience with biologics is still limited, both with regard to efficacy and, more importantly, safety. Although preliminary results are encouraging, these drugs are also not curative, need parenteral administration, have significant adverse effects, and additionally, loss of efficacy on long-term therapy as well as disease unresponsiveness have been observed. Therefore, the search for safer, orally administered newer and cheaper drugs is imperative.
Griffiths CE, Barker JN. Pathogenesis and clinical features of psoriasis. Lancet 2007;370:263-71.[Google Scholar]
Liem WH, Mccullough JL, Weinstein GD. Effectiveness of topical therapy for psoriasis: Results of a national survey. Cutis 1995;55:306-10.[Google Scholar]
Stern RS, Nijsten T, Feldman SR, Margolis DJ, Rolstad T. Psoriasis is common, carries a substantial burden even when not extensive, and is associated with widespread treatment dissatisfaction. J Investig Dermatol Symp Proc 2004;9:136-9.[Google Scholar]
Roenigk HH, Auerbach R, Maibach HI, Weinstein G, Lebwohl M. Methotrexate in psoriasis: Consensus conference. J Am Acad Dermatol 1998;38:478-85.[Google Scholar]
Johnston A, Gudjonsson JE, Sigmundsdottir H, Ludviksson BR, Valdimarsson H. The anti-inflammatory action of methotrexate is not mediated by lymphocyte apoptosis, but by the suppression of activation and adhesion molecules. Clin Immunol 2005;114:154-63.[Google Scholar]
Menter A, Korman NJ, Elmets CA, Feldman SR, Gelfand JM, Gordon KB, et al. Guidelines of care for the management of psoriasis and psoriatic arthritis: Section 4. Guidelines of care for the management and treatment of psoriasis with traditional systemic agents. J Am Acad Dermatol 2009;61:451-85.[Google Scholar]
Saurat JH, Stingl G, Dubertret L, Papp K, Langley RG, Ortonne JP, et al. Efficacy and safety results from the randomized controlled comparative study of adalimumab vs. methotrexate vs. placebo in patients with psoriasis (CHAMPION). Br J Dermatol 2008;158:558-66.[Google Scholar]
Kumar B, Saraswat A, Kaur I. Short-term methotrexate therapy in psoriasis: A study of 197 patients. Int J Dermatol 2002;41:444-8.[Google Scholar]
Braun J, Kastner P, Flaxenberg P, Wahrisch J, Hanke P, Demary W, et al. Comparison of the clinical efficacy and safety of subcutaneous versus oral administration of methotrexate in patients with rheumatoid arthritis. Arthritis Rheum 2008;58:73-81.[Google Scholar]
Salim A, Tan E, Ilchyshyn A, Berth-Jones J. Folic acid supplementation during treatment of psoriasis with methotrexate: A randomized, double-blind, placebo-controlled trial. Br J Dermatol 2006;154:1169-74.[Google Scholar]
Chlαdek J, Simkovα M, Vaneckovα J, Hroch M, Chlαdkova J, Martνnkovα J, et al. The effect of folic acid supplementation on the pharmacokinetics and pharmacodynamics of oral methotrexate during the remission-induction period of treatment for moderate-to-severe plaque psoriasis. Eur J Clin Pharmacol 2008;64:347-55.[Google Scholar]
Prey S, Paul C. Effect of folic or folinic acid supplementation on methotrexate-associated safety and efficacy in inflammatory disease: a systematic review. Br J Dermatol 2009;160:622-8.[Google Scholar]
Heydendael VM, Spuls PI, Opmeer BC, de Borgie CA, Reitsma JB, Goldschmidt WF, et al. Methotrexate versus cyclosporine in moderate-to-severe chronic plaque psoriasis. N Engl J Med 2003;349:658-65.[Google Scholar]
Flytstrom I, Stenberg B, Svensson A. Methotrexate vs. ciclosporin in psoriasis: Effectiveness, quality of life and safety. A randomized controlled trial. Br J Dermatol 2008;158:116-21.[Google Scholar]
Kaur I, Dogra S, De D, Kanwar AJ. Systemic methotrexate treatment in childhood psoriasis: Further experience in 24 children from India. Pediatr Dermatol 2008;25:184-8.[Google Scholar]
Warren RB, Brown BC, Carmichael AJ, Griffiths CE. Long-term control of recalcitrant psoriasis with combination infliximab and methotrexate. Clin Exp Dermatol 2009;34:415-6.[Google Scholar]
Heikkilδ H, Ranki A, Cajanus S, Karvonen SL. Infliximab combined with methotrexate as long-term treatment for erythrodermic psoriasis. Arch Dermatol 2005;141:1607-10.[Google Scholar]
Driessen RJ, van de Kerkhof PC, de Jong EM. Etanercept combined with methotrexate for high-need psoriasis. Br J Dermatol 2008;159:460-3.[Google Scholar]
Mease PJ, Gladman DD, Keystone EC. Alefacept in Psoriatic Arthritis Study Group. Alefacept in combination with methotrexate for the treatment of psoriatic arthritis: Results of a randomized, double-blind, placebo-controlled study. Arthritis Rheum 2006;54:1638-45.[Google Scholar]
Prodanovich S, Kirsner RS, Kravetz JD, Ma F, Martinez L, Federman DG. Association of psoriasis with coronary artery, cerebrovascular, and peripheral vascular diseases and mortality. Arch Dermatol 2009;145:700-3.[Google Scholar]
Dierkes J, Westphal S. Effect of drugs on homocysteine concentrations. Semin Vasc Med 2005;5:124-39.[Google Scholar]
Prodanovich S, Ma F, Taylor JR, Pezon C, Fasihi T, Kirsner RS. Methotrexate reduces incidence of vascular diseases in veterans with psoriasis or rheumatoid arthritis. J Am Acad Dermatol 2005;52:262-7.[Google Scholar]
Gisondi P, Targher G, Zoppini G, Girolomoni G. Non-alcoholic fatty liver disease in patients with chronic plaque psoriasis. J Hepatol 2009;51:758-64.[Google Scholar]
Chalmers RJ, Kirby B, Smith A, Burrows P, Little R, Horan M, et al. Replacement of routine liver biopsy by procollagen III aminopeptide for monitoring patients with psoriasis receiving long-term methotrexate: A multicentre audit and health economic analysis. Br J Dermatol 2005;152:444-50.[Google Scholar]
Maurice PD, Maddox AJ, Green CA, Tatnall F, Schofield JK, Stott DJ. Monitoring patients on methotrexate: Hepatic fibrosis not seen in patients with normal serum assays of aminoterminal peptide of type III procollagen. Br J Dermatol 2005;152:451-8.[Google Scholar]
Rosenberg WM, Voelker M, Thiel R, Becka M, Burt A, Schuppan D, et al. Serum markers detect the presence of liver fibrosis: A cohort study. Gastroenterology 2004;127:1704-13.[Google Scholar]
Myers RP, Tainturier MH, Ratziu V, Piton A, Thibault V, Imbert-Bismut F, et al. Prediction of liver histological lesions with biochemical markers in patients with chronic hepatitis B. J Hepatol 2003;39:222-30.[Google Scholar]
Rossi E, Adams L, Prins A, Bulsara M, de Boer B, Garas G, et al. Validation of the FibroTest biochemical markers score in assessing liver fibrosis in hepatitis C patients. Clin Chem 2003;49:450-4.[Google Scholar]
Afdhal NH, Nunes D. Evaluation of liver fibrosis: A concise review. Am J Gastroenterol 2004;99:1160-74.[Google Scholar]
Faerber L, Braeutigam M, Weidinger G, Mrowietz U, Christophers E, Schulze HJ, et al. Cyclosporine in severe psoriasis: Results of a meta-analysis in 579 patients. Am J Clin Dermatol 2001;2:41-7.[Google Scholar]
Ho VC, Griffiths CE, Berth-Jones J, Papp KA, Vanaclocha F, Dauden E, et al. Intermittent short courses of cyclosporine microemulsion for the long-term management of psoriasis: A 2-year cohort study. J Am Acad Dermatol 2001;44:643-51.[Google Scholar]
Berth-Jones J, Henderson CA, Munro CS, Rogers S, Chalmers RJ, Boffa MJ, et al. Treatment of psoriasis with intermittent short course cyclosporin (Neoral): A multicenter study. Br J Dermatol 1997;136:527-30.[Google Scholar]
Mahe E, Bodemer C, Pruszkowski A, Teillac-Hamel D, de Prost Y. Cyclosporine in childhood psoriasis. Arch Dermatol 2001;137:1532-3.[Google Scholar]
Perrett CM, Ilchyshyn A, Berth-Jones J. Cyclosporin in childhood psoriasis. J Dermatolog Treat 2003;14:113-8.[Google Scholar]
Dadlani C, Orlow SJ. Treatment of children and adolescents with methotrexate, cyclosporine, and etanercept: Review of the dermatologic and rheumatologic literature. J Am Acad Dermatol 2005;52:316-40.[Google Scholar]
Markham T, Watson A, Rogers S. Adverse effects with long term cyclosporin for severe psoriasis. Clin Exp Dermatol 2002;27:111-4.[Google Scholar]
Powles AV, Hardman CM, Porter WM, Cook T, Hulme B, Fry L. Renal function after 10 years′ treatment with cyclosporin for psoriasis. Br J Dermatol 1998;138:443-9.[Google Scholar]
Lowe NJ, Wieder JM, Rosenbach A, Johnson K, Kunkel R, Bainbridge C, et al. Long-term low-dose cyclosporine therapy for severe psoriasis: Effects on renal function and structure. J Am Acad Dermatol 1996;35:710-9.[Google Scholar]
Paul CF, Ho VC, McGeown C, Christophers E, Schmidtmann B, Guillaume JC, et al. Risk of malignancies in psoriasis patients treated with cyclosporine: A 5 year cohort study. J Invest Dermatol 2003;120:211-6.[Google Scholar]
Jegasothy BV, Ackerman CD, Todo S, Fung JJ, Abu-Elmagd K, Starzl TE. Tacrolimus (FK 506) - a new therapeutic agent for severe recalcitrant psoriasis. Arch Dermatol 1992;128:781-5.[Google Scholar]
Bos JD, Witkamp L, Zonnevald IM, Ruzicka T, Szarmach H, Szczerkowska-Dobosz A. Systemic tacrolimus (FK 506) is effective for the treatment of psoriasis in a double-blind, placebo-controlled study: The European FK 506 multicenter psoriasis study group. Arch Dermatol 1996;132:419-23.[Google Scholar]
Rappersberger K, Komar M, Ebelin ME, Scott G, Burtin P, Greig G, et al. Pimecrolimus identifies common genomic anti-inflammatory profile, is clinically highly effective in psoriasis and is well tolerated. J Invest Dermatol 2002;119:876-87.[Google Scholar]
Gottlieb AB, Griffiths CE, Ho VC, Lahfa M, Mrowietz U, Murrell DF, et al; Multi-Centre Investigator Group. Oral pimecrolimus in the treatment of moderate to severe chronic plaque-type psoriasis: A double-blind, multicentre, randomized, dose-finding trial. Br J Dermatol 2005;152:1219-27.[Google Scholar]
Bissonnette R, Papp K, Poulin Y, Lauzon G, Aspeslet L, Huizinga R, et al; ISA247 Psoriasis Study Group. A randomized, multicenter, double-blind, placebo-controlled phase 2 trial of ISA247 in patients with chronic plaque psoriasis. J Am Acad Dermatol 2006;54:472-8.[Google Scholar]
Papp K, Bissonnette R, Rosoph L, Wasel N, Lynde CW, Searles G, et al. Efficacy of ISA247 in plaque psoriasis: A randomised, multicentre, double-blind, placebo-controlled phase III study. Lancet 2008;371:1337-42.[Google Scholar]
Goldfarb MT, Ellis CN, Gupta AK, Tincoff T, Hamilton TA, Voorhees JJ. Acitretin improves psoriasis in a dose-dependent fashion. J Am Acad Dermatol 1988;18:655-62.[Google Scholar]
Van de Kerkhof PC. Update on retinoid therapy of psoriasis in: An update on the use of retinoids in dermatology. Dermatol Ther 2006;9:252-63.[Google Scholar]
Lebwohl M, Drake L, Menter A, Koo J, Gottlieb AB, Zanolli M, et al. Consensus conference: acitretin in combination with UVB or PUVA in the treatment of psoriasis. J Am Acad Dermatol 2001;45:544-53.[Google Scholar]
Gisondi P, Del Giglio M, Cotena C, Girolomoni G. Combining etanercept and acitretin in the therapy of chronic plaque psoriasis: A 24-week, randomized, controlled, investigator-blinded pilot trial. Br J Dermatol 2008;158:1345-9.[Google Scholar]
Allergan, Inc. Tazoral for the treatment of moderate to very severe plaque psoriasis: briefing document prepared by Allergan for the Dermatologic and Ophthalmic Drugs Advisory Committee and Drug Safety and Risk Management Advisory Committee meeting [online]. Available from URL: www.fda.gov/ohrms/dockets/ac/04/briefing/2004-4062B1_01_Allergan-Back ground.pdf[Google Scholar]
Smit JV, Franssen ME, de Jong EM, Lambert J, Roseeuw DI, De Weert J, et al. A phase II multicenter clinical trial of systemic bexarotene in psoriasis. J Am Acad Dermatol 2004;51:249-56.[Google Scholar]
Lehmann JC, Listopad JJ, Rentzsch CU, Igney FH, von Bonin A, Hennekes HH, et al. Dimethylfumarate induces immunosuppression via glutathione depletion and subsequent induction of heme oxygenase 1. J Invest Dermatol 2007;127:835-45.[Google Scholar]
Balasubramaniam P, Stevenson O, Berth-Jones J. Fumaric acid esters in severe psoriasis, including experience of use in combination with other systemic modalities. Br J Dermatol 2004;150:741-6.[Google Scholar]
Wain EM, Darling MI, Pleass RD, Barker JN, Smith CH. Treatment of severe, recalcitrant, chronic plaque psoriasis with fumaric acid esters: A prospective study. Br J Dermatol 2010;162:427-34.[Google Scholar]
Reich K, Thaci D, Mrowietz U, Kamps A, Neureither M, Luger T. Efficacy and safety of fumaric acid esters in the long-term treatment of psoriasis--a retrospective study (FUTURE) J Dtsch Dermatol Ges 2009;7:603-11.[Google Scholar]
Layton AM, Sheehan-Dare RA, Goodfield MJ, Cotterill JA. Hydroxyurea in the management of therapy resistant psoriasis. Br J Dermatol 1989;121:647-53.[Google Scholar]
Kumar B, Saraswat A, Kaur I. Rediscovering hydroxyurea: its role in recalcitrant psoriasis. Int J Dermatol 2001;40:530-4.[Google Scholar]
Sharma VK, Dutta B, Ramam M. Hydroxyurea as an alternative therapy for psoriasis. Indian J Dermatol Venereol Leprol 2004;70:13-7.[Google Scholar]
Ranjan N, Sharma NL, Shanker V, Mahajan VK, Tegta GR. Methotrexate versus hydroxycarbamide (hydroxyurea) as a weekly dose to treat moderate-to-severe chronic plaque psoriasis: A comparative study. J Dermatolog Treat 2007;18:295-300.[Google Scholar]
Gach JE, Berth-Jones J. Successful treatment of recalcitrant psoriasis with a combination of infliximab and hydroxyurea. J Dermatolog Treat 2003;14:226-8.[Google Scholar]
Haufs MG, Beissert S, Grabbe S, Schutte B, Luger TA. Psoriasis vulgaris treated successfully with mycophenolate mofetil. Br J Dermatol 1998;138:179-81.[Google Scholar]
Zhou Y, Rosenthal D, Dutz F, Ho V. Mycophenolate mofetil (CellCept) for psoriasis: A two-center prospective open-label clinical trial. J Cutan Med Surg 2003;7:193-7.[Google Scholar]
Geilen CC, Arnold M, Orfanos CE. Mycophenolate mofetil as a systemic antipsoriatic agent: Positive experience in 11 patients. Br J Dermatol 2001;144:583-6.[Google Scholar]
Beissert S, Pauser S, Sticherling M, Frieling U, Loske KD, Frosch PJ, et al. A Comparison of Mycophenolate Mofetil with Ciclosporine for the Treatment of Chronic Plaque-Type Psoriasis. Dermatology 2009;219:126-32.[Google Scholar]
Forman SB, Higginson R, Garrett AB. Psoriasis and psoriatic arthritis in a patient with HIV: Response to mycophenolate mofetil treatment. J Drugs Dermatol 2008;7:972-3.[Google Scholar]
Rallis E, Anyfantakis V. Coexistent psoriasis and bullous pemphigoid responding to mycophenolate mofetil monotherapy. Skinmed 2008;7:101-2.[Google Scholar]
Berth-Jones J, Todd G, Hutchinson PE, Thestrup-Pedersen K, Vanhoutte FP. Treatment of psoriasis with oral liarozole: a dose-ranging study. Br J Dermatol 2000;143:1170-6.[Google Scholar]
Bhushan M, Burden AD, McElhone K, James R, Vanhoutte FP, Griffiths CE. Oral liarozole in the treatment of palmoplantar pustular psoriasis: A randomized, double-blind, placebo-controlled study. Br J Dermatol 2001;145:546-53.[Google Scholar]
Verfaille CJ, Thissen CA, Bovenschen HJ, Mertens J, Steijlen PM, van de Kerkhof PC. Oral R115866 in the treatment of moderate to severe plaque-type psoriasis. J Eur Acad Dermatol Venereol 2007;21:1038-46.[Google Scholar]
Geria AN, Scheinfeld NS. Talarozole, a selective inhibitor of P450-mediated all-trans retinoic acid for the treatment of psoriasis and acne. Curr Opin Investig Drugs 2008;9:1228-37.[Google Scholar]
Kaltwasser JP, Nash P, Gladman D, Rosen CF, Behrens F, Jones P, et al. Efficacy and safety of leflunomide in the treatment of psoriatic arthritis and psoriasis: A multinational, double-blind, randomized, placebo-controlled clinical trial. Arthritis Rheum 2004;50:1939-50.[Google Scholar]
Prakash A, Jarvis B. Leflunomide: A review of its use in active rheumatoid arthritis. Drugs 1999;58:1137-64.[Google Scholar]
Rapamune [package insert]. Philadelphia: Wyeth Pharmaceuticals; 2006.[Google Scholar]
Reitamo S, Spuls P, Sassolas B, Lahfa M, Claudy A, Griffiths CE. Sirolimus European Psoriasis Study Group. Efficacy of sirolimus (rapamycin) administered concomitantly with a subtherapeutic dose of cyclosporin in the treatment of severe psoriasis: A randomized controlled trial. Br J Dermatol 2001;145:438-45.[Google Scholar]
Frigerio E, Colombo MD, Franchi C, Altomare A, Garutti C, Altomare GF. Severe psoriasis treated with a new macrolide: Everolimus. Br J Dermatol 2007;156:372-4.[Google Scholar]
Shafiq N, Malhotra S, Pandhi P, Gupta M, Kumar B, Sandhu K. Pilot trial: Pioglitazone versus placebo in patients with plaque psoriasis (the P6). Int J Dermatol 2005;44:328-33.[Google Scholar]
Mittal R, Malhotra S, Pandhi P, Kaur I, Dogra S. Efficacy and safety of combination Acitretin and Pioglitazone therapy in patients with moderate to severe chronic plaque-type psoriasis: A randomized, double-blind, placebo-controlled clinical trial. Arch Dermatol 2009;145:387-93.[Google Scholar]
Bongartz T, Coras B, Vogt T, Schφlmerich J, Mόller-Ladner U. Treatment of active psoriatic arthritis with the PPARgamma ligand pioglitazone: An open-label pilot study. Rheumatology (Oxford) 2005;44:126-9.[Google Scholar]
Pershadsingh HA, Sproul JA, Benjamin E, Finnegan J, Amin NM. Treatment of psoriasis with troglitazone therapy. Arch Dermatol 1998;134:1304-5.[Google Scholar]
Ellis CN, Varani J, Fisher GJ, Zeigler ME, Pershadsingh HA, Benson SC, et al. Troglitazone improves psoriasis and normalizes models of proliferative skin disease. Arch Dermatol 2000;136:609-16.[Google Scholar]
Ellis CN, Barker JN, Haig AE, Parker CA, Daly S, Jayawardene DA. Avandia Psoriasis Study Group. Placebo response in two long-term randomized psoriasis studies that were negative for rosiglitazone. Am J Clin Dermatol 2007;8:93-102.[Google Scholar]
Parulkar AA, Pendergrass ML, Granda-Ayala R, Lee TR, Fonseca VN. Nonhypoglycemic effects of thiazolidinediones. Ann Intern Med 2001;134:61-71.[Google Scholar]
Du Vivier A, Munro DD, Verbov J. Treatment of psoriasis with azathioprine. Br Med J 1974;1:49-51.[Google Scholar]
Greaves MW, Dawber R. Azathioprine in psoriasis. Br Med J 1970;2:237-8.[Google Scholar]
Burnett PE. Bullous pemphigoid and psoriasis vulgaris. Dermatol Online J 2003;9:19.[Google Scholar]
Roeder C, Driesch PV. Psoriatic erythroderma and bullous pemphigoid treated successfully with acitretin and azathioprine. Eur J Dermatol 1999;9:537-9.[Google Scholar]
Snow JL, Gibson LE. The role of genetic variation in thiopurine methyltransferase activity and the efficacy and/or side effects of azathioprine therapy in dermatologic patients. Arch Dermatol 1995;131:193-7.[Google Scholar]
Ehrlich A, Booher S, Becerra Y, Borris DL, Figg WD, Turner ML, et al. Micellar paclitaxel improves severe psoriasis in a prospective phase II pilot study. J Am Acad Dermatol 2004;50:533-40.[Google Scholar]
Khandavilli S, Panchagnula R. Nanoemulsions as versatile formulations for paclitaxel delivery: peroral and dermal delivery studies in rats. J Invest Dermatol 2007;127:154-62.[Google Scholar]
Dupont E, Savard PE, Jourdain C, Juneau C, Thibodeau A, Ross N, et al. Antiangiogenic properties of a novel shark cartilage extract: potential role in the treatment of psoriasis. J Cutan Med Surg 1998;2:146-52.[Google Scholar]
Sauder DN, Dekoven J, Champagne P, Croteau D, Dupont E. Neovastat (AE-941), an inhibitor of angiogenesis: Randomized phase I/II clinical trial results in patients with plaque psoriasis. J Am Acad Dermatol 2002;47:535-41.[Google Scholar]
Lehrer A, Bressanelli A, Wachsmann V, Bottasso O, Bay ML, Singh M, et al. Immunotherapy with Mycobacterium vaccae in the treatment of psoriasis. FEMS Immunol Med Microbiol 1998;21:71-7.[Google Scholar]
Balagon MV, Walsh DS, Tan PL, Cellona RV, Abalos RM, Tan EV, et al. Improvement in psoriasis after intradermal administration of heat-killed Mycobacterium vaccae. Int J Dermatol 2000;39:51-8.[Google Scholar]
Balagon MV, Tan PL, Prestidge R, Cellona RV, Abalos RM, Tan EV, et al. Improvement in psoriasis after intradermal administration of delipidated, deglycolipidated Mycobacterium vaccae (PVAC): Results of an open-label trial. Clin Exp Dermatol 2001;26:233-41.[Google Scholar]
Dalbeth N, Yeoman S, Dockerty JL, Highton J, Robinson E, Tan PL, et al. A randomised placebo controlled trial of delipidated, deglycolipidated Mycobacterium vaccae as immunotherapy for psoriatic arthritis. Ann Rheum Dis 2004;63:718-22.[Google Scholar]
Netto EM, Takahashi D, de Fαtima Paim de Oliveira M, Barbosa P, Ferraz N, Paixγo A, et al. Phase II randomized, placebo-controlled trial of M. vaccae-derived protein (PVAC) for the treatment of psoriasis. Vaccine 2006;24:5056-63.[Google Scholar]
Rath N, Kar HK. Efficacy of intradermal heat-killed Mycobacterium w in psoriasis: a pilot study. Int J Dermatol 2003;42:756-7.[Google Scholar]
Kumar B, Sandhu K, Kaur I. Role of Mycobacterium w vaccine in the management of psoriasis. Br J Dermatol 2005;152:380-2.[Google Scholar]
Cather JC, Cather JC, Abramovits W. Investigational therapies for psoriasis. J Am Acad Dermatol 2003;49:S133-8.[Google Scholar]
Marcusson JA, Wetterberg L. Peptide-T in the treatment of psoriasis and psoriatic arthritis. A case report. Acta Derm Venereol 1989;69:86-8.[Google Scholar]
Raychaudhuri SP, Farber EM, Raychaudhuri SK. Immunomodulatory effects of peptide T on Th 1/Th 2 cytokines. Int J Immunopharmacol 1999;21:609-15.[Google Scholar]
Marcusson JA, Talme T, Wetterberg L, Johansson O. Peptide T a new treatment for psoriasis? A study of nine patients. Acta Derm Venereol 1991;71:479-83.[Google Scholar]
Baroni A, Paoletti I, Greco R, Satriano RA, Ruocco E, Tufano MA, et al. Immunomodulatory effects of a set of amygdalin analogues on human keratinocyte cells. Exp Dermatol 2005;14:854-9.[Google Scholar]
Wierzbicka E, Tourani JM, Guillet G. Improvement of psoriasis and cutaneous side-effects during tyrosine kinase inhibitor therapy for renal metastatic adenocarcinoma. A role for epidermal growth factor receptor (EGFR) inhibitors in psoriasis? Br J Dermatol 2006;155:213-4.[Google Scholar]
Keshtgarpour M, Dudek. AZ SU-011248, a vascular endothelial growth factor receptor-tyrosine kinase inhibitor, controls chronic psoriasis. Transl Res 2007;149:103-6.[Google Scholar]
Norman P. BMS-582949: crystalline form of a p38alpha inhibitor? WO2008079857. Expert Opin Ther Pat 2009;19:1165-8.[Google Scholar]
Skvara H, Dawid M, Kleyn E, Wolff B, Meingassner JG, Knight H, et al. The PKC inhibitor AEB071 may be a therapeutic option for psoriasis. J Clin Invest 2008;118:3151-9.[Google Scholar]
Gottlieb AB, Strober B, Krueger JG, Rohane P, Zeldis JB, Hu CC, et al. An open-label, single-arm pilot study in patients with severe plaque-type psoriasis treated with an oral anti-inflammatory agent, apremilast. Curr Med Res Opin 2008;24:1529-38.[Google Scholar]
Raychaudhuri SP, Raychaudhuri SK. Role of NGF and neurogenic inflammation in the pathogenesis of psoriasis. Prog Brain Res 2004;146:433-7.[Google Scholar]
Raychaudhuri SP, Sanyal M, Weltman H, Kundu-Raychaudhuri S. K252a, a high-affinity nerve growth factor receptor blocker, improves psoriasis: An in vivo study using the severe combined immunodeficient mouse-human skin model. J Invest Dermatol 2004;122:812-9.[Google Scholar]