TAZAROTENE

Tazarotene gel, 0.05% is indicated for the topical treatment of patients with plaque psoriasis of up to 20% body surface area involvement.

The safety of tazarotene gel use on more than 20% body surface area has not been established in psoriasis  [see Warnings and Precautions ( 5.1) and Use in Specific Populations ( 8.1)].

It is recommended that treatment starts with tazarotene gel, 0.05%, with strength increased to 0.1% if tolerated and medically indicated. Apply a thin film (2 mg/cm ²) of tazarotene gel once per day, in the evening, to cover only the psoriatic lesions on no more than 20% of body surface area. If a bath or shower is taken prior to application, the skin should be dry before applying the gel. If emollients are used, they should be applied at least an hour before application of tazarotene gel. Because unaffected skin may be more susceptible to irritation, application of tazarotene to these areas should be carefully avoided. Tazarotene gel was investigated for up to 12 months during clinical trials for psoriasis.

Based on data from animal reproduction studies, retinoid pharmacology and the potential for systemic absorption, tazarotene gel may cause fetal harm when administered to a pregnant female and is contraindicated during pregnancy. Tazarotene elicits malformations and developmental effects associated with retinoids after topical and oral administration to pregnant rats and rabbits during organogenesis.

Systemic exposure to tazarotenic acid is dependent upon the extent of the body surface area treated. In patients treated topically over sufficient body surface area, exposure could be in the same order of magnitude as in orally treated animals.

Tazarotene is a teratogenic substance and causes fetal malformations in animals, and it is not known what level of exposure is required for teratogenicity in humans [see Clinical Pharmacology ( 12.3)].

There were thirteen reported pregnancies in subjects who participated in the clinical trials for topical tazarotene. Nine of the subjects had been treated with topical tazarotene, and the other four had been treated with vehicle. One of the subjects who was treated with tazarotene cream elected to terminate the pregnancy for non-medical reasons unrelated to treatment. The other eight pregnant women who were inadvertently exposed to topical tazarotene during the clinical trials subsequently delivered apparently healthy babies. As the exact timing and extent of exposure in relation to the gestation times are not certain, the significance of these findings is unknown.

Females of Child-bearing Potential

Females of child-bearing potential should be warned of the potential risk and use adequate birth-control measures when tazarotene gel is used. The possibility that a female of child-bearing potential is pregnant at the time of institution of therapy should be considered.

A negative result for pregnancy test should be obtained within 2 weeks prior to tazarotene gel therapy. Tazarotene gel therapy should begin during a normal menstrual period [see Use in Specific Populations ( 8.1)].

Application of tazarotene gel may cause excessive irritation in the skin of certain sensitive individuals. Local reactions (including blistering and skin desquamation, pruritus, burning, erythema) and hypersensitivity adverse reactions (including urticaria) have been observed with topical tazarotene.

If these adverse reactions occur, consider discontinuing the medication or reducing the dosing frequency, as appropriate, until the integrity of the skin is restored. Alternatively, patients with psoriasis who are being treated with the 0.1% concentration can be switched to the lower concentration. Frequency of application should be closely monitored by careful observation of the clinical therapeutic response and skin tolerance. Therapy can be resumed, or the drug concentration or frequency of application can be increased as the patient becomes able to tolerate treatment.

Concomitant topical medications and cosmetics that have a strong drying effect should be avoided. It is also advisable to "rest" a patient's skin until the effects of such preparations subside before treatment with tazarotene gel is initiated.

Tazarotene gel, should not be used on eczematous skin, as it may cause severe irritation. Weather extremes, such as wind or cold, may be more irritating to patients using tazarotene gel.

Because of heightened burning susceptibility, exposure to sunlight (including sunlamps) should be avoided unless deemed medically necessary, and in such cases, exposure should be minimized during the use of tazarotene gel. Patients must be warned to use sunscreens and protective clothing when using tazarotene gel. Patients with sunburn should be advised not to use tazarotene gel until fully recovered. Patients who may have considerable sun exposure due to their occupation and those patients with inherent sensitivity to sunlight should exercise particular caution when using tazarotene gel.

Tazarotene gel should be administered with caution if the patient is also taking drugs known to be photosensitizers (e.g., thiazides, tetracyclines, fluoroquinolones, phenothiazines, sulfonamides) because of the increased possibility of augmented photosensitivity.

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.

Psoriasis

A total of 439 subjects 14 to 87 years of age were treated with tazarotene gel, 0.05% and 0.1% in two controlled clinical trials. The most frequent adverse events reported with tazarotene gel, 0.05% and 0.1% occurring in 10 to 30% of subjects, in descending order, included pruritus, burning/stinging, erythema, worsening of psoriasis, irritation, and skin pain. Reactions occurring in 1 to 10% of subjects included rash, desquamation, irritant contact dermatitis, skin inflammation, fissuring, bleeding, and dry skin. Increases in “psoriasis worsening” and “sun-induced erythema” were noted in some subjects over the 4th to 12th months of treatment as compared to the first three months of a 1 year study. In general, the incidence of adverse events with tazarotene gel 0.05% was 2 to 5% lower than that seen with tazarotene gel 0.1%.

Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. The following adverse reactions have been identified during postapproval use of tazarotene.

Skin and subcutaneous tissue disorders: blister, dermatitis, urticaria, skin exfoliation, skin discoloration (including skin hyperpigmentation or skin hypopigmentation), swelling at or near application sites, and pain.

Risk Summary

Based on data from animal reproduction studies, retinoid pharmacology, and the potential for systemic absorption, tazarotene gel may cause fetal harm when administered to a pregnant female and is contraindicated during pregnancy. Safety in pregnant females has not been established. The potential risk to the fetus outweighs the potential benefit to the mother from tazarotene gel during pregnancy; therefore, tazarotene gel should be discontinued as soon as pregnancy is recognized [see Contraindications ( 4), Warnings and Precautions ( 5.1), Clinical Pharmacology ( 12.3)] . Limited case reports of pregnancy in females enrolled in clinical trials for tazarotene gel have not established a clear association with tazarotene and major birth defects or miscarriage risk. Because the exact timing and extent of exposure in relation to the gestational age are not certain, the significance of these findings is unknown.

In animal reproduction studies with pregnant rats, tazarotene dosed topically during organogenesis at 0.5 times the maximum systemic exposure in subjects treated with the maximum recommended human dose (MRHD) of tazarotene gel, 0.1% resulted in reduced fetal body weights and reduced skeletal ossification. In animal reproduction studies with pregnant rabbits dosed topically with tazarotene gel at 7 times the maximum systemic exposure in subjects treated with the MRHD of tazarotene gel, 0.1%, there were single incidences of known retinoid malformations, including spina bifida, hydrocephaly, and heart anomalies.

In animal reproduction studies with pregnant rats and rabbits, tazarotene dosed orally during organogenesis at 0.5 and 13 times, respectively, the maximum systemic exposure in subjects treated with the MRHD of tazarotene gel, 0.1% resulted in malformations, fetal toxicity, developmental delays, and/or behavioral delays. In pregnant rats, tazarotene dosed orally prior to mating through early gestation resulted in decreased litter size, decreased numbers of live fetuses, decreased fetal body weights, and increased malformations at doses approximately 2 times higher than the maximum systemic exposure in subjects treated with the MRHD of tazarotene gel, 0.1% [see Data].

The background risk of major birth defects and miscarriage for the indicated population is unknown. Adverse outcomes in pregnancy occur regardless of the health of the mother or the use of medications. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively.

Data

Animal Data

In rats, a tazarotene gel, 0.05% formulation dosed topically during gestation days 6 through 17 at 0.25 mg/kg/day, which represented 0.5 times the maximum systemic exposure in subjects treated with the MRHD of tazarotene gel, 0.1% (i.e., 2 mg/cm ²over a 20% body surface area), resulted in reduced fetal body weights and reduced skeletal ossification. Rabbits dosed topically with 0.25 mg/kg/day tazarotene gel, which represented 7 times the maximum systemic exposure in subjects treated with the MRHD of tazarotene gel, 0.1%, during gestation days 6 through 18 were noted with single incidences of known retinoid malformations, including spina bifida, hydrocephaly, and heart anomalies.

When tazarotene was given orally to animals, developmental delays were seen in rats, and malformations and post-implantation loss were observed in rats and rabbits at doses producing 0.5 and 13 times, respectively, the maximum systemic exposure in subjects treated with the MRHD of tazarotene gel, 0.1%.

In female rats orally administered 2 mg/kg/day of tazarotene from 15 days before mating through gestation day 7, which represented 2 times the maximum systemic exposure in subjects treated with the MRHD of tazarotene gel, 0.1%, classic developmental effects of retinoids were observed including decreased number of implantation sites, decreased litter size, decreased numbers of live fetuses, and decreased fetal body weights. A low incidence of retinoid-related malformations was observed at that dose.

In a pre- and postnatal development toxicity study, topical administration of tazarotene gel (0.125 mg/kg/day) to pregnant female rats from gestation day 16 through lactation day 20 reduced pup survival, but did not affect the reproductive capacity of the offspring. Based on data from another study, the maximum systemic exposure in the rat would be 0.3 times the maximum systemic exposure in subjects treated with the MRHD of tazarotene gel, 0.1%.

Risk Summary

There is no information regarding the presence of tazarotene in human milk, the effects on the breastfed infant, or the effects on milk production. After single topical doses of ¹⁴C-tazarotene gel to the skin of lactating rats, radioactivity was detected in rat milk. The lack of clinical data during lactation precludes a clear determination of the risk of tazarotene gel to an infant during lactation; therefore, the developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for tazarotene gel and any potential adverse effects on the breastfed child from tazarotene gel or from the underlying maternal condition.

Pregnancy Testing

Pregnancy testing is recommended for females of reproductive potential within 2 weeks prior to initiating tazarotene gel therapy which should begin during a menstrual period.

Contraception

Females

Based on animal studies, tazarotene gel may cause fetal harm when administered to a pregnant woman [see Use in Specific Populations ( 8.1)] . Advise females of reproductive potential to use effective contraception during treatment with tazarotene gel.

The safety and efficacy of tazarotene gel have not been established in pediatric patients with psoriasis under the age of 12 years.

Of the total number of subjects in clinical trials of tazarotene gel for plaque psoriasis, 163 were over the age of 65. Subjects over 65 years of age experienced more adverse events and lower treatment success rates after 12 weeks of use of tazarotene gel compared with those 65 years of age and younger. Currently there is no other clinical experience on the differences in responses between the elderly and younger subjects, but greater sensitivity of some older individuals cannot be ruled out.

Tazarotene is a retinoid prodrug which is converted to its active form, the carboxylic acid of tazarotene, by deesterification. Tazarotenic acid binds to all three members of the retinoic acid receptor (RAR) family: RARα, RARβ, and RARγ, but shows relative selectivity for RARβ, and RARγ and may modify gene expression. The clinical significance of these findings for the treatment of plaque psoriasis is unknown.

The pharmacodynamics of tazarotene gel in the treatment of plaque psoriasis are unknown.

Following topical application, tazarotene undergoes esterase hydrolysis to form its active metabolite, tazarotenic acid. Little parent compound could be detected in the plasma. Tazarotenic acid was highly bound to plasma proteins (greater than 99%).

Tazarotene and tazarotenic acid were metabolized to sulfoxides, sulfones and other polar metabolites which were eliminated through urinary and fecal pathways. The half-life of tazarotenic acid was approximately 18 hours, following topical application of tazarotene to normal or psoriatic skin.

The human in vivostudies described below were conducted with tazarotene gel applied topically at approximately 2 mg/cm ²and left on the skin for 10 to 12 hours. Both the peak plasma concentration (C _max) and area under the plasma concentration time curve (AUC) refer to the active metabolite only.

Two single, topical dose studies were conducted using ¹⁴C-tazarotene gel. Systemic absorption, as determined from radioactivity in the excreta, was less than 1% of the applied dose (without occlusion) in six subjects with psoriasis and approximately 5% of the applied dose (under occlusion) in six healthy subjects. One non-radiolabeled single-dose study comparing the 0.05% gel to the 0.1% gel in healthy subjects indicated that the C _maxand AUC were 40% higher for the 0.1% gel.

After 7 days of topical dosing with measured doses of tazarotene 0.1% gel on 20% of the total body surface without occlusion in 24 healthy subjects, the C _maxfor tazarotenic acid was 0.72 ± 0.58 ng/mL (mean ± SD) occurring 9 hours after the last dose, and the AUC _0-24hrfor tazarotenic acid was 10.1 ± 7.2 ng·hr/mL. Systemic absorption was 0.91 ± 0.67% of the applied dose.

In a 14-day study in five subjects with psoriasis, measured doses of tazarotene 0.1% gel were applied daily by nursing staff to involved skin without occlusion (8 to 18% of total body surface area; mean ± SD: 13 ± 5%). The C _maxfor tazarotenic acid was 12.0 ± 7.6 ng/mL occurring 6 hours after the final dose, and the AUC _0-24hrfor tazarotenic acid was 105 ± 55 ng·hr/mL. Systemic absorption was 14.8 ± 7.6% of the applied dose. Extrapolation of these results to represent dosing on 20% of total body surface yielded estimates for tazarotenic acid with C _maxof 18.9 ± 10.6 ng/mL and AUC _0-24hrof 172 ± 88 ng·hr/mL.

An in vitropercutaneous absorption study, using radiolabeled drug and freshly excised human skin or human cadaver skin, indicated that approximately 4 to 5% of the applied dose was in the stratum corneum (tazarotene: tazarotenic acid = 5:1) and 2 to 4% was in the viable epidermis-dermis layer (tazarotene: tazarotenic acid = 2:1) 24 hours after topical application of the gel.

A long-term study of tazarotene following oral administration of 0.025, 0.050, and 0.125 mg/kg/day to rats showed no indications of increased carcinogenic risks. Based on pharmacokinetic data from a shorter-term study in rats, the highest dose of 0.125 mg/kg/day was anticipated to give systemic exposure in the rat 0.3 times that seen in subjects treated with the MRHD of tazarotene gel, 0.1%.

A long-term study with topical administration of up to 0.1% tazarotene in a gel formulation in mice terminated at 88 weeks showed that dose levels of 0.05, 0.125, 0.25, and 1 mg/kg/day (reduced to 0.5 mg/kg/day for males after 41 weeks due to severe dermal irritation) revealed no apparent carcinogenic effects when compared to vehicle control animals. Systemic exposure at the highest dose was 2 times that seen in subjects treated with the MRHD of tazarotene gel, 0.1%.

Tazarotene was non-mutagenic in the Ames assay and did not produce structural chromosomal aberrations in a human lymphocyte assay. Tazarotene was non-mutagenic in the CHO/HGPRT mammalian cell forward gene mutation assay and was non-clastogenic in the in vivo mouse micronucleus test.

No impairment of fertility occurred in rats when male animals were treated for 70 days prior to mating and female animals were treated for 14 days prior to mating and continuing through gestation and lactation with topical doses of tazarotene gel up to 0.125 mg/kg/day. Based on data from another study, the systemic drug exposure in the rat at the highest dose was 0.3 times that observed in subjects treated with the MRHD of tazarotene gel, 0.1%.

No impairment of mating performance or fertility was observed in male rats treated for 70 days prior to mating with oral doses of up to 1 mg/kg/day tazarotene, which produced systemic exposure that was approximately equivalent to that observed in subjects treated with the MRHD of tazarotene gel, 0.1%.

No impairment of mating performance or fertility was observed in female rats treated for 15 days prior to mating and continuing through gestation day 7 with oral doses of tazarotene up to 2 mg/kg/day. However, there was a significant decrease in the number of estrous stages and an increase in developmental effects at that dose, which produced systemic exposure 2 times that observed in subjects treated with the MRHD of tazarotene gel, 0.1% [see Use in Specific Populations ( 8.1)] .