Mechlorethamine Hydrochloride

VALCHLOR is indicated for the topical treatment of Stage IA and IB mycosis fungoides-type cutaneous T-cell lymphoma in patients who have received prior skin-directed therapy. VALCHLOR is an alkylating drug indicated for the topical treatment of Stage IA and IB mycosis fungoides-type cutaneous T-cell lymphoma in patients who have received prior skin-directed therapy ( 1 ).

The active ingredient in VALCHLOR is mechlorethamine. Each tube of VALCHLOR contains 60g of 0.016% w/w mechlorethamine clear gel (equivalent to 0.02% mechlorethamine HCl). Gel: 0.016% w/w of mechlorethamine (equivalent to 0.02% mechlorethamine HCl) in 60g tubes ( 3 )

The use of VALCHLOR is contraindicated in patients with known severe hypersensitivity to mechlorethamine. Hypersensitivity reactions, including anaphylaxis, have occurred with topical formulations of mechlorethamine. Severe hypersensitivity to mechlorethamine ( 4 )

Mucosal or eye injury: VALCHLOR exposure to mucous membranes, especially of the eyes, can cause mucosal injury which may be severe. Eye injury may lead to blindness. Immediately irrigate for at least 15 minutes followed by immediate medical consultation ( 5.1 ). Secondary exposure to VALCHLOR: individuals other than the patient must avoid skin contact with VALCHLOR ( 2.2 , 5.2 ). Dermatitis: Monitor patients for redness, swelling, inflammation, itchiness, blisters, ulceration, and secondary skin infections. Stop treatment or reduce dose frequency ( 2.1 , 5.3 ). Non-melanoma skin cancer: Monitor patients during and after treatment ( 5.4 ). Embryo-fetal toxicity: May cause fetal harm ( 5.5 ). Flammable gel: VALCHLOR is an alcohol-based gel. Avoid fire, flame, and smoking until the gel has dried ( 2.2 , 5.6 ).

5.1 Mucosal or Eye Injury Exposure of the eyes to mechlorethamine causes pain, burns, inflammation, photophobia, and blurred vision. Blindness and severe irreversible anterior eye injury may occur. Advise patients that if eye exposure occurs, (1) immediately irrigate for at least 15 minutes with copious amounts of water, normal saline, or a balanced salt ophthalmic irrigating solution and (2) obtain immediate medical care (including ophthalmologic consultation). Exposure of mucous membranes such as the oral mucosa or nasal mucosa causes pain, redness, and ulceration, which may be severe. Should mucosal contact occur, immediately irrigate for at least 15 minutes with copious amounts of water, followed by immediate medical consultation.

5.2 Secondary Exposure to VALCHLOR Avoid direct skin contact with VALCHLOR in individuals other than the patient. Risks of secondary exposure include dermatitis, mucosal injury, and secondary cancers. Follow recommended application instructions to prevent secondary exposure [ see Dosage and Administration ( 2.2 ) ].

5.3 Dermatitis The most common adverse reaction was dermatitis, which occurred in 56% of the patients [ see Adverse Reactions ( 6.1 ) ]. Dermatitis was moderately severe or severe in 23% of patients. Monitor patients for redness, swelling, inflammation, itchiness, blisters, ulceration, and secondary skin infections. The face, genitalia, anus, and intertriginous skin are at increased risk of dermatitis. Follow dose modification instructions for dermatitis [ see Dosage and Administration ( 2.1 ) ].

5.4 Non-Melanoma Skin Cancer Four percent (4%, 11/255) of patients developed a non-melanoma skin cancer during the clinical trial or during one year of post-treatment follow-up: 2% (3/128) of patients receiving VALCHLOR, and 6% (8/127) of patients receiving the mechlorethamine ointment comparator. Some of these non-melanoma skin cancers occurred in patients who had received prior therapies known to cause non-melanoma skin cancer. Monitor patients for non-melanoma skin cancers during and after treatment with VALCHLOR. Non-melanoma skin cancer may occur on any area of the skin, including untreated areas.

5.5 Embryo-fetal Toxicity Based on case reports in humans, findings in animal reproduction studies, its mechanism of action, and genotoxicity findings, mechlorethamine may cause fetal harm. There are case reports of children born with malformations in pregnant women systemically administered mechlorethamine. Mechlorethamine was teratogenic and embryo-lethal after a single subcutaneous administration to animals. Advise women to avoid becoming pregnant while using VALCHLOR. If this drug is used during pregnancy or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to a fetus [ see Use in Specific Populations ( 8.1 ) ].

5.6 Flammable Gel Alcohol-based products, including VALCHLOR, are flammable. Follow recommended application instructions [ see Dosage and Administration ( 2.2 ) ].

The following clinically significant adverse reactions are discussed in greater detail in other sections of the prescribing information: Mucosal or eye injury [ see Warnings and Precautions ( 5.1 ) ] Secondary exposure to VALCHLOR [ see Warnings and Precautions ( 5.2 ) ] Dermatitis [ see Warnings and Precautions ( 5.3 ) ] Non-melanoma skin cancer [ see Warnings and Precautions ( 5.4 ) ] The most common adverse reactions (≥5%) are dermatitis, pruritus, bacterial skin infection, skin ulceration or blistering, and hyperpigmentation ( 6.1 ). To report SUSPECTED ADVERSE REACTIONS, contact Helsinn Therapeutics (U.S.), Inc., at 1-855-482-5245 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch .

6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared with rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. In a randomized, observer-blinded, controlled trial, VALCHLOR 0.016% (equivalent to 0.02% mechlorethamine HCl) was compared to an Aquaphor ® -based mechlorethamine HCl 0.02% ointment (Comparator) [ see Clinical Studies ( 14 ) ]. The maximum duration of treatment was 12 months. Sixty-three percent (63%) of patients in the VALCHLOR arm and 67% in the comparator arm completed 12 months of treatment. The body system associated with the most frequent adverse reactions was skin and subcutaneous tissue disorders. The most common adverse reactions (occurring in at least 5% of the patients) are shown in Table 1 . Table 1. Most Commonly Reported (≥5%) Cutaneous Adverse Reactions VALCHLOR N=128 % of patients Comparator N=127 % of patients Any Grade Moderately-Severe or Severe Any Grade Moderately-Severe or Severe Dermatitis 56 23 58 17 Pruritus 20 4 16 2 Bacterial skin infection 11 2 9 2 Skin ulceration or blistering 6 3 5 2 Skin hyperpigmentation 5 0 7 0 In the clinical trial, moderately-severe to severe skin-related adverse events were managed with treatment reduction, suspension, or discontinuation. Discontinuations due to adverse reactions occurred in 22% of patients treated with VALCHLOR and 18% of patients treated with the comparator. Sixty-seven percent (67%) of the discontinuations for adverse reactions occurred within the first 90 days of treatment. Temporary treatment suspension occurred in 34% of patients treated with VALCHLOR and 20% of patients treated with the comparator. Reductions in dosing frequency occurred in 23% of patients treated with VALCHLOR and 12% of patients treated with the comparator. Reductions in hemoglobin, neutrophil count, or platelet count occurred in 13% of patients treated with VALCHLOR and 17% treated with Comparator.

No drug interaction studies have been performed with VALCHLOR. Systemic exposure has not been observed with topical administration of VALCHLOR; therefore, systemic drug interactions are not likely.

Lactation: Advise not to breastfeed ( 8.2 ).

8.1 Pregnancy Risk Summary Based on case reports in humans, findings in animal reproduction studies, its mechanism of action, and genotoxicity findings, mechlorethamine may cause fetal harm. Available published case reports in pregnant women receiving intravenous mechlorethamine demonstrate that mechlorethamine can cause major birth defects when a pregnant woman is systemically exposed. In animal reproduction studies, subcutaneous administration of mechlorethamine to pregnant rats and ferrets during organogenesis resulted in embryo‐fetal mortality, alterations to growth, and structural abnormalities. Based on limited available data with VALCHLOR use in pregnant women, if VALCHLOR is used during pregnancy or if the patient becomes pregnant while taking this drug, patient should be advised of the potential risk to the fetus. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. 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 Human Data The limited available data with VALCHLOR use in pregnant women does not show evidence of congenital malformation in newborns. Cases of newborns with congenital malformations have been reported in women who received systemic mechlorethamine during pregnancy. Animal Data Mechlorethamine caused fetal malformations in the rat and ferret when given as single subcutaneous injections of 1 mg/kg. Other findings in animals included embryo lethality and growth retardation when administered as a single subcutaneous injection.

8.2 Lactation Risk Summary There are no data on the presence of mechlorethamine or its metabolites in human milk, the effects of the drug on the breastfed child, or the effects of the drug on milk production. Because of the potential for topical or systemic exposure to VALCHLOR through exposure to the mother's skin and the potential for serious adverse reactions in the breastfed child from mechlorethamine, advise patients not to breastfeed during treatment with VALCHLOR.

8.3 Females and Males of Reproductive Potential Contraception Females Advise female patients of reproductive potential to use effective contraception during treatment with VALCHLOR. A barrier method of contraception should be used to avoid direct exposure of reproductive organs to VALCHLOR. Males Based on genotoxicity findings, advise males with female partners of reproductive potential to use effective contraception during treatment with VALCHLOR [ see Nonclinical Toxicology ( 13.1 ) ]. A barrier method of contraception should be used to avoid direct exposure of reproductive organs to VALCHLOR. Infertility Based on animal data, mechlorethamine may impair fertility in males and females [ see Nonclinical Toxicology ( 13.1 ) ]. The reversibility of the effect on fertility is unknown.

8.4 Pediatric Use Safety and effectiveness in pediatric patients have not been established.

8.5 Geriatric Use A total of 79 patients age 65 and older (31% of the clinical trial population) were treated with either VALCHLOR or the comparator in the clinical trial. Forty-four percent (44%) of patients age 65 or older treated with VALCHLOR achieved a CAILS response compared to 66% of patients below the age of 65. Seventy percent (70%) of patients age 65 and older experienced cutaneous adverse reactions and 38% discontinued treatment due to adverse reactions, compared to 58% and 14% in patients below the age of 65, respectively. Similar differences in discontinuation rates between age subgroups were observed in the comparator group.

Mechlorethamine, also known as nitrogen mustard, is an alkylating agent which inhibits rapidly proliferating cells.