Acitretin. A review of its pharmacology and therapeutic use

Successful treatment with retinoids in patients with lupus nephritis

Lupus nephritis is a major manifestation of systemic lupus erythematosus. Treatment with such immunosuppressive agents as corticosteroids or cyclophosphamide can decrease the progression of lupus nephritis; however, these agents have potentially severe adverse reactions. Therefore, the development of new drugs with fewer side effects is needed. Here, we report 2 patients with lupus that were treated successfully with retinoids. Initially, both patients were treated with 60 mg/d of prednisolone. However, nephrotic syndrome was not improved. Subsequently, treatment with 10 mg/d of all-trans-retinoic acid was started orally and elicited a good response, showing a decrease in proteinuria. Although additional controlled clinical studies are needed to confirm these findings, we suggest that therapy using retinoids may represent a novel approach to the treatment of patients with lupus nephritis.

Oral liarozole vs. acitretin in the treatment of ichthyosis: a phase II/III multicentre, double-blind, randomized, active-controlled study

BACKGROUND

Liarozole, a retinoic acid metabolism blocking agent, has been granted orphan drug status for congenital ichthyosis by the European Commission and the U.S. Food and Drug Administration.

OBJECTIVES

The purpose of this trial was to investigate the efficacy, tolerability and safety of oral liarozole vs. acitretin in patients with ichthyosis.

METHODS

In this double-blind comparative trial of liarozole vs. acitretin, 32 patients with ichthyosis were randomized to be treated with either oral liarozole 75 mg in the morning and 75 mg in the evening or with acitretin 10 mg in the morning and 25 mg in the evening for 12 weeks. Clinical efficacy, tolerability and safety were monitored.

RESULTS

Between-group comparisons for efficacy and tolerability revealed no statistically significant differences except for scaling on the trunk at baseline which was significantly worse in the liarozole group (P = 0.024) and showed a more pronounced improvement in this group than in the acitretin-treated patients (P = 0.047). Based on the overall evaluation of the response to treatment at endpoint, 10 of 15 patients in the liarozole group and 13 of 16 patients in the acitretin group were considered by the investigator to be at least markedly improved. The expected retinoic acid-related adverse events were mostly mild to moderate and tended to occur less frequently in the liarozole group. No serious adverse events related to the drugs occurred.

CONCLUSIONS

The present study indicates that liarozole at a daily dose of 150 mg is equally effective as a treatment for ichthyosis as acitretin but shows a trend towards a more favourable tolerability profile. The results of this trial warrant further clinical trials to confirm efficacy and safety of liarozole as an orphan drug in ichthyosis.

A review of acitretin, a systemic retinoid for the treatment of psoriasis

Acitretin is a second-generation, systemic retinoid that has been approved for the treatment of psoriasis since 1997. It can be considered one of the treatments of choice for pustular and erythrodermic psoriasis. However, the efficacy of acitretin as a monotherapy for plaque psoriasis is less, although it is often used in combination therapy with other systemic psoriasis therapies, especially ultraviolet B or psoralen plus ultraviolet A phototherapy, to increase efficacy. Such combination treatments may potentially minimise toxicity by using lower doses of each of the two agents. All systemic retinoids are potent teratogens. The most common side effects are mucocutanous effects such as cheilitis and hair loss, which are dose-dependent. Acitretin is not immunosuppressive, is generally safe for long-term use and has no time limit restrictions, which makes it useful in combination therapy and for maintenance therapy.

Blastomycosis-like pyoderma: Successful treatment with low-dose acitretin

Blastomycosis-like pyoderma typically presents as verrucous plaque(s) with a purulent discharge through multiple sinuses. Two patients with blastomycosis-like pyoderma developing on significantly sun-damaged skin are presented: an 84-year-old man with multiple painful nodules and plaques, and a 92-year-old woman with a solitary plaque on the left calf. Histopathology showed pseudoepitheliomatous hyperplasia with dermal foci of suppuration. Staphylococcus aureus was isolated from a biopsy specimen in the first patient, whereas the latter patient had Prevotella and Corynebacterium species. Investigations for fungi and mycobacteria yielded negative results. These microbiological findings further supported the clinicopathological diagnosis. Both patients failed to respond to oral doxycycline despite the in vitro susceptibility of the organisms. Treatment with low-dose oral acitretin was successful in both patients after 3-4 months.

Tazarotene does not affect the pharmacokinetics and efficacy of a norethindrone/ethinylestradiol oral contraceptive

OBJECTIVE

To determine the pharmacokinetic and pharmacodynamic interaction between oral tazarotene and an oral contraceptive containing norethindrone 1mg and ethinylestradiol 0.035 mg (Ortho-Novum 1/35).

DESIGN

Two separate open-label, parallel-group, single-centre, pharmacokinetic and pharmacodynamic interaction studies.

PARTICIPANTS AND METHODS

Twenty-seven healthy women (age 20-55 years) completed Study I, with a duration of 64 days during three consecutive menstrual cycles. Ortho-Novum 1/35 was taken once daily from study day 0 (first cycle day 1) to day 61 (third cycle day 6), and oral tazarotene 1.1 mg was coadministered daily from study day 34 (second cycle day 7) to day 61. Twenty-nine healthy women (age 20-44 years) completed Study II, with a duration of 75 days during three consecutive menstrual cycles. Ortho-Novum 1/35 was taken once daily from study day 0 (first cycle day 1) to day 74 (third cycle day 19), and oral tazarotene 6 mg was coadministered daily from study day 48 (second cycle day 21) to day 74. In both studies, the pharmacokinetics of tazarotenic acid on study day 61 (third cycle day 6) were evaluated from plasma tazarotenic acid concentrations. Pharmacokinetic parameters of plasma norethindrone and ethinylestradiol were compared before and after tazarotene administration (cycle day 6 of the second and third cycles, respectively). Serum luteinising hormone (LH) and follicle-stimulating hormone (FSH) concentrations were compared before and after tazarotene administration (cycle days 2, 4 and 6 of the second and third cycles, respectively). In Study II, serum progesterone concentrations were also determined on cycle days 18 and 20 of the second and third cycles. Tazarotenic acid was determined by liquid chromatography-tandem mass spectrometry. Ethinylestradiol and norethindrone were determined by gas chromatography-mass spectrometry. LH and FSH were assayed by microparticle enzyme immunoassay in Study I and by double-antibody radioimmunoassay in Study II. Progesterone was determined by solid-phase radioimmunoassay.

RESULTS

In Study I (tazarotene 1.1 mg), the area under the plasma concentration-time curve from zero to 24 hours (AUC24) and the peak concentration in plasma (Cmax) for tazarotenic acid were 121 +/- 27 microg. h/L and 28.9 +/- 9.4 microg/L (mean +/- SD), respectively. In Study II (tazarotene 6 mg), AUC24 and Cmax for tazarotenic acid were 379 +/- 78 microg. h/L and 111 +/- 37 microg/L (mean +/- SD), respectively. In both studies, for both norethindrone and ethinylestradiol, the 90% CIs of AUC24 and Cmax on cycle day 6 before and after tazarotene administration were within the 80-125% boundary. In Study I, the 90% CIs of serum FSH and LH concentrations on cycle day 4 were within the 80-125% boundary. FSH and LH concentrations on cycle day 6 were marginally/partially outside the 80-125% boundary as a result of high variability. However, the mean FSH and LH serum concentrations on cycle day 6 of the third cycle were lower than those of the second cycle. In Study II, the 90% CIs of serum FSH, LH and progesterone concentrations were all within the 80-125% boundary, except for LH on cycle day 2. LH concentrations on cycle day 2 were marginally/partially outside the 80-125% boundary as a result of high variability. However, the mean serum LH concentration on cycle day 2 of the third cycle was lower than that of the second cycle.

CONCLUSIONS

Oral tazarotene up to 6 mg once daily does not affect the pharmacokinetics and efficacy of Ortho-Novum 1/35.

Biopharmaceutics of β-cyclodextrin derivative-based formulations of acitretin in sprague-dawley rats

Acitretin, an active metabolite of etretinate, is as effective as etretinate in the treatment of psoriasis. Recently, we developed some water-soluble formulations of acitretin with 2-hydroxypropyl-beta-cyclodextrin (HPBCD)/randomly substituted methyl-beta-cyclodextrin (RMBCD). In this study, the biopharmaceutic properties of these formulations were tested in Sprague-Dawley rats. After single intravenous dosing (2.5, 5, or 10 mg/kg) with the HPBCD-based formulation, the area under the plasma concentration-time curve of acitretin increased proportionally with the dose and its clearance remained unchanged within the tested dose range. We also found that the RMBCD-based formulation of acitretin improved its bioavailability and decreased the variations in various pharmacokinetic parameters. The improved biopharmaceutic properties of RMBCD-based acitretin might be attributed to its enhanced aqueous solubility. The elimination of acitretin through bile excretion was also studied. Our results indicated that the major fraction of acitretin (approximately 40%) was excreted in the bile as beta-glucuronide conjugate and only trace amounts were excreted as unconjugated acitretin (approximately 0.5%). This finding further confirmed the importance of conjugated metabolism and biliary excretion in the elimination of this drug.

Inclusion of Acitretin into Cyclodextrins: Phase Solubility, Photostability, and Physicochemical Characterization

Acitretin, a retinoid for the treatment of severe psoriasis, exhibits extremely low aqueous solubility and high photosensitivity. This study investigated the effects of the complexation of acitretin with the respective hydroxypropyl-beta-cyclodextrin (HPBCD) and randomly substituted methyl-beta-cyclodextrin (RMBCD) on the aqueous solubility and photostability of the drug. Phase-Solubility studies indicated that the solubility of acitretin was dramatically improved by formation of complexes and further increased by pH adjustment. Stability constants were much higher for acitretin complexed with RMBCD than with HPBCD. Both cyclodextrins acted to decrease degradation of acitretin in solution. The physicochemical properties of solid inclusion complexes were characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, and X-ray diffractometry. Molecular modeling with MMFF94s force field (SYBYL V6.6) was utilized to predict the preferred orientation of acitretin in the cyclodextrin cavity and the main structural features responsible for the enhancement of its solubility and photostability.

Current concepts in psoriasis and its treatment

Many advances have been made in our understanding of the biology of psoriasis over the past 20 years. We are close to knowing the genetic determinants of psoriasis. There is now greater insight into the immunological mechanisms that produce the phenotype, and the possibility of intervening selectively to antagonise some of these mechanisms is becoming a reality. Nevertheless, psoriasis remains an enigmatic disease, and much of the suffering it produces is not adequately addressed. The sheer number of treatments that are used therapeutically suggests a lack of efficacy and/or toxicity of many of these approaches. In this review, we aim to briefly describe the biology of psoriasis, document the key features of treatments that are available or under development, and explain how these treatments can be used effectively to manage this chronic relapsing disease.

Acitretin-associated thrombotic stroke

OBJECTIVE

To report a case of thrombotic stroke. The etiology was difficult to identify, but was finally ascribed to psoriatic treatment with acitretin.

CASE SUMMARY

Treatment with acitretin was prescribed for a 52-year-old white woman for long-standing psoriasis. Thirty-four days later, she developed nausea, vomiting, vertigo, and headaches, followed by left lateropulsion, which impeded standing and lying. Both neurologic examination and magnetic nuclear imaging indicated a rectangular infarct in the vermis cerebelli and a small bulbar infarct. Time-of-flight magnetic resonance angiography confirmed the presence of a thrombus at the beginning of the left vertebral artery. After heparin-based treatment and physiotherapy, the evolution was favorable.

DISCUSSION

Etiology identification of the stroke included cardiogenic pathology and coagulopathy, but acitretin treatment was considered the likeliest explanation. On review of the literature, this seems to be the first case of a thrombotic event associated with acitretin.

CONCLUSIONS

Acitretin should be considered as a possible cause of thrombotic stroke; this possibility should be kept in mind when patients taking acitretin develop an unexplained thrombotic event.

Tazarotene plus UVB phototherapy in the treatment of psoriasis

BACKGROUND

The addition of oral retinoids to phototherapy may accelerate and enhance antipsoriatic efficacy, but can result in systemic adverse events and additional laboratory monitoring costs.

OBJECTIVE

Our purpose was to determine whether the topical addition of tazarotene to UVB phototherapy improves efficacy without problems related to photosensitivity.

METHODS

Bilateral target plaques were randomized to receive two of the following, one on each plaque once daily for 14 days: tazarotene 0.1% gel, vehicle gel, or no treatment. Thereafter, the same treatments were continued 3 times per week, plus UVB phototherapy 3 times per week, for an additional 67 days.

RESULTS

Tazarotene plus UVB phototherapy achieved faster and significantly greater reductions in plaque elevation and scaling throughout treatment and achieved at least 50% improvement from the pretreatment baseline with a significantly lower median cumulative UVB exposure than vehicle gel plus UVB light or UVB phototherapy alone. No case of unusual photosensitivity was noted in the tazarotene plus UVB treatment group.

CONCLUSION

The addition of tazarotene to UVB phototherapy improves and accelerates efficacy and maintains acceptable safety and tolerability.

Acitretin in psoriasis: an overview of adverse effects

Oral retinoids are among the drugs of choice for pustular and erythrodermic psoriasis. In addition, retinoids are effective in combination with other topical and systemic agents for the treatment of plaque-type psoriasis. Acitretin, the active retinoid metabolite, has replaced etretinate in retinoid therapy of psoriasis because of its more favorable pharmacokinetic profile, including a significantly shorter half-life. Retinoids, including acitretin, are potent teratogens, leading to strict requirements for pregnancy prevention during and after their use. Other retinoid side effects are generally preventable or manageable through proper patient selection, dose adjustments, and routine monitoring. Mucocutaneous side effects such as cheilitis and hair loss are the most common dose-dependent side effects, requiring dose reduction in some patients. Less common effects such as hepatotoxicity, serum lipid alterations, pancreatitis, and possible skeletal effects are also discussed.

High dose etretinate and interferon-alpha--a phase I study in squamous cell carcinomas and transitional cell carcinomas

Simultaneous exposure to retinoids and interferons can result in enhanced antiproliferative and differentiating effects on malignant lesions. We studied the toxicity and the potential efficacy of an association of high dose etretinate and Interferon-alpha (IFN-alpha) in squamous cell carcinomas of the lung, head and neck, the esophagus, cervix and the penis, as well as in transitional carcinomas of the bladder. The treatment consisted of etretinate (Tigason) 4 mg/kg/d on 2, 3, 4 and finally 5 consecutive days every other week and IFN-alpha (Roferon) 6 Mio IU sc. q.d. for 5 days every week. Of 24 patients enrolled, 23 were assessable for toxicity and 20 for response. With two occurrences of grade 3 cutaneous toxicity, the administration of etretinate (Tigason) 4 mg/kg/d on 5 consecutive days every other week and IFN-alpha (Roferon) 6 Mio IU sc. q.d. for 5 days every week was considered to be the MTD. Toxicity was mild otherwise, mostly at grades 1 and 2 level, causing fatigue, skin peeling and erythema, mucositis and cheilitis; 3 PR (partial response) and 8 SD (stable disease) were recorded. Of the responders, one patient had become resistant to cisplatin-based chemotherapy and the other two had at no time ever received systemic therapy. We conclude that the association of high doses of etretinate and IFN-alpha has moderate activity in squamous cell carcinomas, is well tolerated, and that IFN-alpha plays a role in the improved tolerance of the retinoid.

N-linked glycoside and glucuronide conjugates of the retinoid, acitretin, are biologically active in cornea and conjunctiva

The purpose of this study was to test two water-soluble, synthetic retinoids, glucoseamido acitretin and glucuronamido acitretin, for biological activity in cells of the cornea and conjunctiva. Vitamin A-deficient, xerophthalmic rats were treated topically with these retinoids, and corneas were examined histologically for effects on epithelial keratinization. The effect of these retinoids on the proliferation of rabbit conjunctival fibroblasts in culture was also investigated. Glucoseamido acitretin treatment restored a normal cornea after eight to nine days of treatment, while no improvement was observed in the vehicle-treated corneas. Likewise, glucuronamido acitretin application restored a normal corneal surface and reversed keratinization after eight to ten days of treatment. These retinoids caused no irritation of the eye or ocular adnexa. In culture, exposure of conjunctival fibroblasts to glucoseamide acitretin inhibited cell proliferation. Cultures exposed to glucoseamido acitretin at 10(-8) M or 10(-6) M had cell densities 77.3% and 51.9% of control, respectively, after seven days. Glucuronamido acitretin also inhibited cell proliferation. Cultures exposed to glucuronamido acitretin at 10(-8) M had a cell density of 69.2% of control at day seven, while at 10(-6) M this retinoid completely inhibited cell proliferation. These results show that glucoseamide acitretin and glucuronamido acitretin are biologically active in the cornea and conjunctiva, and may be considered for ophthalmic use in diseases involving abnormalities of ocular surface cell differentiation or hyperproliferation of fibroblasts.

The use of retinoids in the pediatric patient

Oral retinoids are molecules derived from vitamin A that represent one of the most important steps forward in dermatologic therapeutics in the present century. The treatment of acne, severe psoriasis, and severe disorders of keratinization, prevalent diseases in children and adolescents, have radically changed since the advent of oral retinoids. Like most highly-effective medications, oral retinoids also have important untoward effects. Specialists, and in particular, dermatologists and pediatricians should be prepared to maneuver the delicate balance between therapeutic efficacy and side effects in order to give the pediatric patient the maximum benefit with the lowest possible risk.

Autoinduction of retinoic acid metabolism to polar derivatives with decreased biological activity in retinoic acid-sensitive, but not in retinoic acid-resistant human breast cancer cells

Previous studies have shown that all-trans-retinoic acid (RA) inhibits in vitro proliferation of hormone-dependent human breast cancer cells but not the growth of hormone-independent cells. Here we report on RA metabolism in breast cancer cells as examined by high performance liquid chromatography analysis and found a correlation with sensitivity to growth inhibition by RA. RA-sensitive T-47D and MCF-7 cells exhibited high rate metabolism to polar metabolites, whereas RA-resistant MDA-MB-231 and MDA-MB-468 cells metabolized RA to a much lesser extent, and almost no polar metabolites could be detected. The high metabolic rate in RA-sensitive cells appears to be the result of autoinduction of RA metabolism, whereas RA-resistant cells showed no such induction of metabolism. We observed furthermore that transfection with retinoic acid receptor-alpha expression vectors in RA-resistant MDA-MB-231 cells resulted in increased RA metabolism and inhibition of cell proliferation. Metabolism of RA, however, seems not to be required to confer growth inhibition of human breast cancer cells. The biological activity of the polar metabolites formed in RA-sensitive cells was found to be equal or lower than that of RA, indicating that RA itself is the most active retinoid in these cells. Together our data suggest that RA-sensitive cells contain mechanisms to activate strongly the catabolism of RA probably to protect them from the continuous exposure to this active retinoid.

Recent advances in the treatment of psoriasis

We have seen great progress in the past decade in our understanding of the pathogenesis of psoriasis. The fruits of this knowledge are being realized in many of the exciting immunologic therapies currently in development. The potential for astute clinical observation to produce effective therapies and to change the direction of research has been proven in the past and still remains as an avenue for the future. Although individual treatments were discussed in this article, combination therapy is likely to continue to play a major role. Additionally, because future therapeutic developments are not likely to be free of toxicity, rotational therapy may still be necessary. Many questions remain unanswered. Substantial progress is just beginning into the.

Oral retinoids--efficacy and toxicity in psoriasis

Psoriasis is a disease of unknown aetiology, affecting approximately 1-3% of the population. In most cases involving relatively localized disease, patients are best managed with either topical therapy alone or topical therapy in combination with UV-phototherapy. However, approximately 35% of patients do not respond well to these conventional treatments or have moderate-to-severe disease requiring more aggressive forms of therapy. The second-generation retinoids, etretinate and its metabolite acitretin, are important additions to the armamentarium of agents used to treat these recalcitrant or severe forms of the disease. Generalized pustular psoriasis generally responds well to high-dose (0.7-1 mg/kg/day) oral retinoid monotherapy. In contrast, increasing small doses of the retinoid are recommended initially in erythrodermic psoriasis in order not to provoke the disease. Long-term clinical experience favours a combination treatment of the retinoid with either topical and/or UV irradiation in chronic plaque-like psoriasis. Both oral retinoids have comparable efficacy and tolerability profiles, and the relapse rates for both drugs are similar. The toxicities associated with both short- and long-term treatment with oral retinoids are significant and include mucocutaneous effects, adverse modulation of serum lipid chemistries, elevation of liver enzymes, and after long-term chronic dosing, skeletal and ligamentous calcification, and hyperostosis. Both etretinate and acitretin, like all retinoids, are known teratogens in animal models, and documented evidence exists for teratogenic activity in humans as well. Consequently, women of childbearing age are strongly advised to avoid pregnancy during treatment and up to 5 years following cessation of therapy with both etretinate and the carboxylic acid metabolite acitretin.

Determination of acitretin in the skin, in the suction blister, and in plasma of human volunteers after multiple oral dosing

Several HPLC methods for quantification of acitretin and its 13-cis isomer in biological fluids have been described. Only limited data are available on determination of this drug in skin samples. Our objective was to improve the sensitivity and selectivity of existing methods to measure drug in small skin samples from humans treated with acitretin. With a new optimized mobile phase [methanol: acetonitrile (7:3, v/v), purified water with 1.5% (v/v) acetic acid, mixed in a 85:15 ratio (v/v)] and a new internal standard (arotinoid ethyl sulfone), a limit of quantification of 1 ng/g tissue was reached. Nine male volunteers were given an oral daily dose of 50 mg acitretin for up to 28 days. Blood and skin samples (punch and shave biopsies, suction blister skin, and fluid) were taken at various time points during and after treatment. Drug concentration and metabolism in plasma and skin samples appeared to be linked in that the trans-isomer concentration was always higher than the cis-isomer concentration during dosing and 3 h after the last dose. However, 7 and 14 days after the last dose in plasma and in all tissue samples (except the shave biopsy), the all-trans-acitretin concentration rapidly decreased and approached the detection limit. In the shave biopsy, the all-trans-acitretin concentration remained higher than the 13-cis-acitretin concentration. Furthermore, the elimination of two isomers from the shave biopsy was delayed.(ABSTRACT TRUNCATED AT 250 WORDS)