Patent Publication Number: US-2020297684-A1

Title: Topical compositions and methods for treating acne vulgaris

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to topical compositions and methods for treating acne vulgaris. In particular, this invention relates to topical pharmaceutical compositions comprising a combination of active ingredients, and methods using the same, for treating acne vulgaris. More particularly, this invention relates to topical pharmaceutical compositions comprising a combination of an anti-bacterial agent and a retinoid, and methods using the same, for treating acne vulgaris. 
     Acne vulgaris (or commonly referred to as acne) is a skin disease affecting more than ninety percent of the population world-wide. Up to fifty million people between the ages of 12 and 24 in the United States experience at least minor acne annually. Acne vulgaris is characterized by skin with scaly red skin (seborrhea), blackheads and whiteheads (open and closed comedones, respectively), pinheads (papules), large papules (nodules), and pustules, which can lead to scarring. The pathogenesis of acne is multifactored, involving seborrhea, microbial proliferation, inflammation, and abnormal desquamation of follicular epithelium. Excessive sebum production, brought about by hormonal changes (in particular, an increase in the production of androgens associated with the onset of puberty) is followed by abnormal desquamation of follicular corneocytes. The mixture of cells and sebum creates an environment for the proliferation of  Propionibacterium acnes . Chemotactic factors released by  P. acnes  attract lymphocytes and neutrophils, as well as producing other pro-inflammatory molecules that lead to inflammation. 
     Acne is not life threatening but severe acne can affect psychological status and social activities. 
     Common current treatments for acne include oral antibiotics for inflammatory acne, oral retinoids for severe acne, topical antibiotics and topical medications with bacteriostatic, anti-inflammatory, or keratolytic properties for mild-to-moderate inflammatory acne. 
     These treatments have been known to produce side effects. For example, side effects of oral antibiotics include nausea, vomiting, diarrhea, abdominal pain and cramps, pruritus, rash, stomatitis, and dizziness. Common side effects of oral retinoids include cheilitis, dry skin and mucous membranes, pruritus, epistasis, and photosensitivity. Side effects of topical antibiotics include local irritation. Side effects of topical retinoids include dryness, scaling, erythema, burning, irritation, and photosensitivity. See; e.g., S. Feldman et al.,  Am. Fam. Physician  (2004), 69(9): 2123-30. The severity of side effects can vary with the retinoids, formulations, and dosages. 
     The need still exists for more effective and safer topical medicaments with reduced adverse effects for the management of acne vulgaris. 
     SUMMARY OF THE INVENTION 
     In general, the present invention provides topical compositions and methods for treating acne vulgaris. 
     In one aspect, the present invention provides topical pharmaceutical compositions comprising a combination of an anti-bacterial agent and a retinoid, and methods using the same, for treating acne vulgaris. 
     In another aspect, the present invention provides topical pharmaceutical compositions comprising a combination of: (a) tretinoin or a pharmaceutically acceptable salt or ester thereof; and (b) benzoyl peroxide. The present invention also provides methods using the compositions, for treating acne vulgaris. 
     In still another aspect, the present invention relates to topical pharmaceutical compositions comprising a combination that is an admixture of a first composition (“Component 1”) comprising tretinoin or a pharmaceutically acceptable salt or ester thereof, and a second composition (“Component 2”) comprising benzoyl peroxide. In yet another aspect, the admixture is formed or prepared substantially immediately prior to the admixture being applied to a subject in need of treatment. 
     In still another aspect of the present invention, the admixture comprises, or is formed or prepared from, substantially equal amounts of the first composition (Component 1) and the second composition (Component 2) substantially immediately prior to the admixture being applied to a subject in need of treatment. 
     In yet another aspect, the admixture comprises tretinoin at about 0.01-0.1 weight percent of the total admixture and benzoyl peroxide at about 1-10 weight percent of the total admixture. 
     In still another aspect of the present invention, the first composition (Component 1) and the second composition (Component 2) comprise aqueous gels. 
     In one embodiment, the aqueous gels comprise a gelling agent that comprises a carboxyvinyl polymer, such as poly(acrylic acid) or a derivative thereof. In another embodiment, such gelling agent comprises a cross-linked poly(acrylic acid). 
     In still another aspect, the present invention provides a method of treating or ameliorating acne vulgaris in a subject. The method comprises topically administering to an affected area of the subject&#39;s body a composition comprising a combination of (a) and tretinoin at about 0.1-0.1 weight percent of the combination; and (b) benzoyl peroxide at about 1-10 weight percent of the combination; in an amount and for a time sufficient to treat or ameliorate such acne vulgaris. 
     Other features and advantages of the present invention will become apparent from the following detailed description and claims. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In general, the present invention provides topical compositions and methods for treating acne vulgaris. 
     Throughout this disclosure, unless otherwise indicated, the concentration of an ingredient of a composition indicated as a percentage is in percent by weight of the total composition. 
     In one aspect, the present invention provides topical pharmaceutical compositions comprising a combination of an anti-bacterial agent and a retinoid, and methods using the same, for treating acne vulgaris. Non-limiting examples of retinoids are tretinoin, isotretinoin, tazarotene, bexarotene, adapalene, etretinate and acitretin. The preferred retinoid is tretinoin. 
     In another aspect, the present invention provides topical pharmaceutical compositions comprising a combination of: (a) tretinoin or a pharmaceutically acceptable salt or ester thereof; and (b) benzoyl peroxide. The present invention also provides methods using such compositions, for treating acne vulgaris. 
     In still another aspect, the present invention relates to topical pharmaceutical compositions comprising a combination that is an admixture of a first composition (Component 1) comprising tretinoin or a pharmaceutically acceptable salt or ester thereof, and a second composition (Component 2) comprising benzoyl peroxide. In yet another aspect, the admixture is formed or prepared substantially immediately prior to the admixture being applied to a subject in need of treatment. In other words, an amount of Component 1 and another amount of component 2 are mixed together to form the admixture substantially immediately prior to applying the admixture to the subject. 
     Since it has been known that tretinoin can be inactivated by ultraviolet (UV) light and is susceptible to oxidization by a strong oxidizing agent such as benzoyl peroxide, the prior art has recommended that, if they are to be used in the same regimen to treat acne vulgaris, they should be applied at different times. For example, tretinoin should be applied at night and never together with benzoyl peroxide. See; e.g., S. Feldman et al.,  Am. Fam. Physician  (2004), 69(9):2123-30. 
     Although Del Rosso et al. ( J. Clin. Aesthet. Dermatol.  (2010), 3(10):26-28) found that tretinoin in a mixture of equal parts of a 0.05% tretinoin gel and a gel containing 5% BPO and clindamycin phosphate was stable at 32° C. for 7 hours, the stability of tretinoin beyond 7 hours or in a mixture without clindamycin phosphate was not known. The present inventors surprisingly discovered that treinoin in an admixture of tretinoin and benzoyl peroxide compositions of the present invention is chemically stable for at least 24 hours, even at 32° C. under room light condition, such that tretinoin and benzoyl peroxide can be administered together in the same composition to treat acne vulgaris. Such stability discovered by the present inventors allows for once-a-day treatment using tretinoin and benzoyl peroxide together in the same composition that has been taught away by Feldman et al. The method of the present invention provides synergistically enhanced efficacy in the treatment of acne vulgaris over the use of each of tretinoin and benzoyl peroxide alone. In other words, the present inventors surprisingly discovered that tretinoin and benzoyl peroxide could be applied together, such as in an admixture of the present invention, not only without evidence of loss of efficacy of either active ingredient, but moreover with enhanced efficacy. 
     The chemical stability of tretinoin in an admixture with benzoyl peroxide of the present invention at room temperature and 32 degrees C., under room light condition is shown in Table 1. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Stability of Tretinoin at Room Condition 
               
               
                 and at 32° C., Under Room Light 
               
            
           
           
               
               
               
               
            
               
                   
                 Time 
                   
                 Assay (% label claim) 
               
            
           
           
               
               
               
               
               
            
               
                   
                 (hr) 
                 Replicate 
                 Room Condition 
                 32° C., Room Light 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 0 
                 top 
                 98.8 
                 98.8 
               
               
                   
                   
                 middle 
                 97.1 
                 97.1 
               
               
                   
                   
                 bottom 
                 98.3 
                 98.3 
               
               
                   
                 1 
                 1 
                 96.8 
                 98.5 
               
               
                   
                   
                 2 
                 97.2 
                 97.1 
               
               
                   
                 3 
                 1 
                 97.8 
                 no data 
               
               
                   
                   
                 2 
                 97.5 
                 no data 
               
               
                   
                 4 
                 1 
                 no data 
                 98.6 
               
               
                   
                   
                 2 
                 no data 
                 98.2 
               
               
                   
                 5 
                 1 
                 97.0 
                 no data 
               
               
                   
                   
                 2 
                 97.3 
                 no data 
               
               
                   
                 8 
                 1 
                 99.5 
                 no data 
               
               
                   
                   
                 2 
                 99.5 
                 no data 
               
               
                   
                 12 
                 1 
                 97.3 
                 98.9 
               
               
                   
                   
                 2 
                 97.8 
                 97.0 
               
               
                   
                 24 
                 1 
                 98.1 
                 96.6 
               
               
                   
                   
                 2 
                 97.4 
                 97.8 
               
               
                   
                   
               
            
           
         
       
     
     More than 97 and 96 percent of treinoin in the original admixture of the present invention remains after 24 hours at room condition and 32° C., under room light, respectively. Such stability ensures that the therapeutic efficacy of tretinoin is not diminished between once-a-day applications. 
     In another aspect, a topical pharmaceutical admixture of the present invention is used to treat or ameliorate signs and symptoms of acne vulgaris in patients suffering from moderate to severe acne vulgaris. 
     In one aspect, the present invention relates to topical pharmaceutical compositions comprising a combination that is an admixture of a first composition (Component 1) comprising tretinoin or a pharmaceutically acceptable salt or ester thereof and a second composition (Component 2) comprising benzoyl peroxide. In yet another aspect, the admixture is formed or prepared substantially immediately prior to the admixture being applied to a subject in need of treatment. 
     In still another aspect of the present invention, the admixture comprises, or is formed or prepared from, Component A and Component B at a volume ratio of about 1:5 to about 5:1. In one embodiment the admixture comprises substantially equal volume amounts of Component 1 and Component 2. The admixture composition of the invention is prepared or formed substantially immediately prior to the admixture being applied to a subject in need of treatment. Regardless of what volume ratio of Component A and Component B is used, the desired amounts of active ingredients may be achieved, for example, in one embodiment wherein tretinoin is present in the admixture at a concentration of about 0.05 weight percent of the total admixture and benzoyl peroxide is present in the admixture at about 2.5 weight percent of the total admixture. 
     In one aspect, an amount of the admixture comprises amounts (by weight) of Component 1 and Component 2 such that, after mixing, tretinoin is present at a concentration of about 0.01-0.1 weight percent of the total admixture and benzoyl peroxide is present at about 1-10 weight percent of the total admixture. In some embodiments, after mixing, tretinoin is present at a concentration of about 0.03-0.08 (or 0.04-0.07, or 0.04-0.06) weight percent of the total admixture and benzoyl peroxide is present at about 1-10 (or 1.5-5, or 2-3) weight percent of the total admixture. In a preferred embodiment, after mixing, tretinoin is present at a concentration of about 0.05 weight percent of the total admixture and benzoyl peroxide is present at about 2.5 weight percent of the total admixture. 
     For example, separately, Component 1 comprises tretinoin at a concentration of 0.02-3 weight percent (or 0.02-2, or 0.02-1, or 0.02-0.5 weight percent), and Component 2 comprises benzoyl peroxide at a concentration of 2-20 weight percent (or 2-15, or 2-10, or 2-6 weight percent). 
     In one aspect, compositions of the present invention are in the dosage form of gel, emulsion (including lotion, cream, and milk), foam, suspension, liquid, spray, paste, or ointment. In certain preferred embodiments, compositions of the present invention comprise aqueous gels. 
     In addition to the active ingredients as disclosed above, compositions of the present invention comprise one or more dermatologically acceptable excipients, such as liquid oils, viscosity-modifying agents, thickening agents, gelling agents, alcohols, surfactants, chelating agents, buffers, preservatives, humectants, emollients, stabilizers, diluents, dispersing agents, emulsifiers, wetting agents, stabilizers, pH adjusters, solvents, or cosolvents. The choice of excipients depends on the desired dosage form. 
     Compositions of the invention may desirably comprise a gelling agent to provide viscosity so that the compositions may be provided in the form of a gel. Preferably, but not necessarily, the gelling agent is miscible or soluble in an aqueous medium. Non-limiting examples of suitable gelling agents are carbomers (also known as carboxy vinyl polymers, which are cross-linked polyacrylic acid), such as Carbopol® and polycarbophil (The Lubrizol Corporation, Wickliffe, Ohio). Carbopol® homopolymers are polymers of acrylic acid crosslinked with allyl sucrose or allylpentaerythritol. Carbopol® copolymers are polymers of acrylic acid and C 10 -C 30  alkyl acrylate crosslinked with allylpentaerythritol. Carbopol® interpolymers are carbomer homopolymers or copolymers that contain a block copolymer of polyethylene glycol and a long chain alkyl acid ester. Noveon® polycarbophil is a polymer of acrylic acid crosslinked with divinyl glycol. 
     In addition, compositions of the invention may desirably comprise one or more thickening agents. Non-limiting examples of such thickening agents include acacia, alginic acid and its salts, hyaluronic acid and its salts, carboxymethylcellulose, ethylcellulose, gelatin, collagen, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropylmethyl cellulose, methylcellulose, poloxamers, polyvinylpyrrolidone, polyvinyl alcohol, tragacanth, xanthan gum, magnesium aluminum silicate, and bentonite. 
     A surfactant or emulsifier is included, if desired or required. Pharmaceutically acceptable anionic, cationic, or non-ionic surfactants may be included in a composition of the present invention. Non-ionic surfactants are preferred. Non-limiting examples of non-ionic surfactants are Octoxynol (also known as Macrogol tetramethylbutylphenyl ether, octylphenoxy polyethoxyethanol, or polyoxyethylene octylphenyl ether), such as Octoxynol 1, 3, 5, 8, 9, 10, 12, 13, 16, 30, 40, 70 (wherein the number indicates the number of repeating oxyethylene units), or other Octoxynols that comprise different numbers of repeating units of oxyethylene in the side chain, sorbitan esters (such as sorbitan monooleate and sorbitan monostearate, commonly known by their trade names Span 80 and Span 60), polysorbates (such as polysorbate 80 (polyoxyethylene sorbitan monooleate), polysorbate 60 (polyoxyethylene sorbitan monostearate), polysorbate 20 (polyoxyethylene sorbitan monolaurate), commonly known by their trade names of Tween® 80, Tween® 60, Tween® 20), poloxamers (synthetic block polymers of ethylene oxide and propylene oxide, such as those commonly known by their trade names of Pluronic®; e.g., Pluronic® F127 or Pluronic® F108), or poloxamines (synthetic block polymers of ethylene oxide and propylene oxide attached to ethylene diamine, such as those commonly known by their trade names of Tetronic®; e.g., Tetronic® 1508 or Tetronic® 908, etc.), other nonionic surfactants such as Brij® (polyoxyethylene alkyl ether having a formula of CH 3 —(CH 2 ) 10-16 —(O—C 2 H 4 ) 1-25 —OH), Myrj® (stearic acid esterified with polyoxyethylene having 40-100 repeating oxyethylene units), and long chain fatty alcohols (e.g., oleyl alcohol, stearyl alcohol, myristyl alcohol, docosahexaenoyl alcohol, etc.) with carbon chains having about 12 or more carbon atoms (e.g., such as from about 12 to about 24 carbon atoms). 
     In addition, polymeric emulsifiers such as those known under the trade name Pemulen™ (The Lubrizol Corporation, Wickliffe, Ohio) may be used. These are polymers of acrylic acid, modified by long chain (C 10 -C 30 ) alkyl acrylates, and crosslinked with allylpentaerythritol. 
     An anionic emulsifier may be used, such as sodium or potassium oleate, triethanolamine stearate, sodium lauryl sulfate, sodium dioctyl sulfosuccinate, and sodium docusate. Less preferred are cationic emulsifiers such as quaternary ammonium salts. Still other emulsifiers include glyceryl monostearate, polyoxyethylene monooleate, polyoxyethylene monostearate, polyoxyethylene monolaurate, potassium oleate, sodium lauryl sulfate, sodium oleate, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan tristearate, sorbitan monooleate, sorbitan trioleate, triethanolamine oleate, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan monooleate, and polyoxyethylene sorbitan trioleate. 
     Compositions of the present invention desirably contain a dermatologically acceptable humectant such as glycerin, sorbitol, hexylene glycol, propylene glycol, or urea. Chelating agents (such as EDTA and its salts), and antioxidants (such as butylated hydroxytoluene (BHT) butylated hydroxyanisole (BHA), sodium metabisulfite, propyl gallate, or cysteine) may be included in a composition of the present invention. 
     In one aspect, separately, Component 1 of the present invention comprises the ingredients at the concentrations shown in Table 2. 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Separate Component 1 of the Present Invention  
               
               
                 for Treating Acne vulgaris 
               
            
           
           
               
               
            
               
                   
                 Concentration (weight percent) 
               
            
           
           
               
               
               
               
            
               
                 Ingredient 
                 Range 1 
                 Range 2 
                 Range 3 
               
               
                   
               
               
                 Retinoid 
                 0.02-2 
                 0.02-1 
                 0.02-0.5 
               
               
                 Humectant 
                   5-20 
                    5-15 
                    7-12 
               
               
                 Gelling/Thickening Agent 
                  0.2-5 
                  0.3-3 
                  0.5-2 
               
               
                 Surfactant/Emulsifier 
                 0.02-2 
                 0.02-1 
                 0.05-0.5 
               
               
                 Moisturizer 
                  0.1-20 
                  0.1-15 
                  0.1-12 
               
               
                 Anti-oxidant 
                 0.01-1 
                 0.01-0.7 
                 0.01-0.5 
               
               
                 Neutralizing Agent 
                 q.s. to adjust 
                 q.s. to adjust 
                 q.s. to adjust 
               
               
                   
                 pH to 4-7 
                 pH to 4-7 
                 pH to 4-7 
               
               
                 Purified water 
                 q.s. to 100 
                 q.s. to 100 
                 q.s. to 100 
               
               
                   
               
            
           
         
       
     
     A non-limiting example of a Component 1 of the present invention comprises a gel comprising tretinoin at a concentration of 0.1 weight percent and a carboxyvinyl polymer gelling agent. 
     In one aspect, separately, Component 2 of the present invention comprises the ingredients at the concentrations shown in Table 3. 
     
       
         
           
               
             
               
                 TABLE 3 
               
             
            
               
                   
               
               
                 Separate Component 2 of the Present Invention  
               
               
                 for Treating Acne vulgaris 
               
            
           
           
               
               
            
               
                   
                 Concentration (weight percent) 
               
            
           
           
               
               
               
               
            
               
                 Ingredient 
                 Range 1 
                 Range 2 
                 Range 3 
               
               
                   
               
            
           
           
               
               
               
               
            
               
                 Antibacterial Agent 
                   2-15 
                   2-10 
                   2-6 
               
               
                 Humectant 
                   5-20 
                   5-15 
                   5-12 
               
               
                 Gelling/Thickening Agent 
                 0.2-5 
                 0.3-3 
                 0.5-2 
               
               
                 Neutralizing Agent 
                 q.s. to adjust 
                 q.s. to adjust 
                 q.s. to adjust 
               
               
                   
                 pH to 4-7 
                 pH to 4-7 
                 pH to 4-7 
               
               
                 Purified water 
                 q.s. to 100 
                 q.s. to 100 
                 q.s. to 100 
               
               
                   
               
            
           
         
       
     
     A non-limiting example of Component 2 of the present invention comprises benzoyl peroxide at a concentration of 5 weight percent in a carboxyvinyl polymer gel. 
     In one aspect the invention comprises a pre-filled dual chambered delivery device wherein one chamber contains Component 1 and the second chamber contains Component 2. The dual chambered delivery device separates Component 1 and Component 2 until each Component is dispensed from the delivery device substantially at the same time to allow for admixing to form the composition of the invention. The dispensing can be achieved via a pump, either metered or non-metered. In one embodiment the delivery system comprises a top part that includes the pump assembly and actuators, and optionally an overcap; and a bottom part that includes the individual chambers enclosed in an outer casing/housing; the top part can snap on the bottom part. In a further embodiment a one-piece dispensing button works cooperatively with the actuators to allow the user to press at any spot on this button to allow the pump to dispense Component 1 and Component 2 at the same time. When the center of the button is pressed, the two gel components are dispensed at a desired volume ratio such as an approximate 1:1 ratio. This spot is optionally marked so that actuation is effected substantially consistently at the same place by end users. 
     A separate Component 1 of a composition of the present invention was prepared as follows. 
     A predetermined amount of a gelling/thickening agent was dissolved completely in a predetermined amount of purified water under agitation. This solution was combined with another solution containing predetermined amounts of tretinoin, moisturizer, humectant, antioxidant, and other optional excipients. The pH was adjusted to a range of desired values. 
     A separate Component 2 of a composition of the present invention was prepared as follows. 
     A predetermined amount of a gelling/thickening agent was dissolved completely in a predetermined amount of water under agitation. This solution was combined with another solution containing predetermined amounts of micronized penzoyl peroxide, humectant and other optional excipients. The pH was adjusted to a range of desired values. 
     In one embodiment, each of Components 1 and 2 is contained in a separate chamber of a two-chamber delivery system, which is a commercially available non-metered dual airless pump. The delivery system comprises a top part that includes the pump assembly, actuators, and an overcap; and a bottom part that includes the individual chambers enclosed in an outer casing/housing. The top part snaps on the bottom part. 
     A one-piece dispensing button works cooperatively with the actuators to allow the user to press at any spot on this button to allow the pump to dispense Component 1 and Component 2 at the same time. When the center of the button is pressed, the two gel components are dispensed at an approximate 1:1 ratio. This spot is marked so that actuation is effected substantially consistently at the same place by end users. The dispensing mechanism may be designed to dispense the two components at other ratios, if desired. 
     A clinical study in acne vulgaris patients was conducted to assess the safety, tolerability, and efficacy of a composition of the present invention (also referred to as “IDP-120” below) in comparison with a composition comprising only tretinoin active ingredient (at effective concentration of 0.05% tretinoin, referred to as “Component A” below), a composition comprising only benzoyl peroxide active ingredient (at effective concentration of 2.5% benzoyl peroxide, referred to as “Component B” below), and the vehicle of said composition of the present invention at weeks 2, 4, 8, and 12. Component A is an admixture of approximately equal weights of Component A 1  and Component A 2 , as shown in Table 4. Component B is an admixture of approximately equal weights of Component B 1  and Component B 2 , as shown in Table 5. IDP-120 is an admixture of approximately equal weights of Component A 1  and Component B 1 . 
     
       
         
           
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                 Component A Composition for Clinical Study 
               
            
           
           
               
               
            
               
                   
                 Concentration 
               
               
                   
                 (weight percent) 
               
            
           
           
               
               
               
            
               
                 Ingredient 
                 Component A 1   
                 Component A 2   
               
               
                   
               
            
           
           
               
               
               
            
               
                 Tretinoin 
                 0.1 
                 0 
               
               
                 Glycerin 
                 9.63 
                 0 
               
               
                 Carbopol 980 
                 0.9 
                 1.75 
               
               
                 Octoxynol-9 
                 0.12 
                 0 
               
               
                 sodium hyaluronate 
                 0.011 
                 0 
               
               
                 soluble collagen 
                 8 
                 0 
               
               
                 BHT 
                 0.021 
                 0 
               
               
                 Methylparaben 
                 0.2 
                 0.17 
               
               
                 benzyl alcohol 
                 0.5 
                 0 
               
               
                 Propylparaben 
                 0 
                 0.03 
               
               
                 propylene glycol 
                   
                 7.5 
               
               
                 titanium dioxide 
                   
                 0.25 
               
               
                 pH adjuster 
                 q.s. to adjust pH to 
                 q.s. to adjust pH to 
               
               
                   
                 5.4-5.5 
                 5.4-5.5 
               
               
                 purified water 
                 q.s. to 100 
                 q.s. to 100 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 5 
               
             
            
               
                   
               
               
                 Component B Composition for Clinical Study 
               
            
           
           
               
               
            
               
                   
                 Concentration 
               
               
                   
                 (weight percent) 
               
            
           
           
               
               
               
            
               
                 Ingredient 
                 Component B 1   
                 Component B 2   
               
               
                   
               
            
           
           
               
               
               
            
               
                 benzoyl peroxide 
                 5 
                 0 
               
               
                 propylene glycol 
                 7.5 
                 0 
               
               
                 Carbopol 980 
                 1.75 
                 0.9 
               
               
                 Methylparaben 
                 0 
                 0.2 
               
               
                 benzyl alcohol 
                 0 
                 0.5 
               
               
                 Propylparaben 
                 0 
                 0.03 
               
               
                 Glycerin 
                 0 
                 9.63 
               
               
                 Octoxynol-9 
                 0 
                 0.9 
               
               
                 sodium hyaluronate 
                 0 
                 0.11 
               
               
                 soluble collagen 
                 0 
                 8 
               
               
                 BHT 
                 0 
                 0.021 
               
               
                 FD&amp;C yellow No.5 
                 0 
                 0.015 
               
               
                 pH adjuster 
                 q.s. to adjust pH 
                 q.s. to adjust pH 
               
               
                   
                 to 5.4-5.5 
                 to 5.4-5.5 
               
               
                 purified water 
                 q.s. to 100 
                 q.s. to 100 
               
               
                   
               
            
           
         
       
     
     This was a multi-center, randomized, double-blind, vehicle-controlled, 12-week study. To be eligible for the study subjects must be at least 9 years of age and have a clinical diagnosis of moderate to severe acne (defined as an Evaluator&#39;s Global Severity Score (“EGSS”) of 3 or 4), presenting with 20-40 inflammatory facial lesions (papules, pustules, and nodules), 20-100 non-inflammatory facial lesions (open and closed comedones), and &lt;2 facial nodules. 
     
       
         
           
               
             
               
                 TABLE 6 
               
             
            
               
                   
               
               
                 Evaluator&#39;s Global Severity Score 
               
            
           
           
               
               
               
            
               
                 Score 
                 Grade 
                 Description 
               
               
                   
               
               
                 0 
                 Clear 
                 Normal, clear skin with no  
               
               
                   
                   
                 evidence of acne vulgaris 
               
               
                 1 
                 Almost  
                 Rare non-inflammatory lesions  
               
               
                   
                 Clear 
                 present, with rare non-inflamed  
               
               
                   
                   
                 papules (papules must be resolving  
               
               
                   
                   
                 and may be hyperpigmented,  
               
               
                   
                   
                 though not pink-red) 
               
               
                 2 
                 Mild 
                 Some non-inflammatory lesions  
               
               
                   
                   
                 are present, with few inflammatory  
               
               
                   
                   
                 lesions (papules/pustules only; no 
               
               
                   
                   
                 nodulocystic lesions) 
               
               
                 3 
                 Moderate 
                 Non-inflammatory lesions  
               
               
                   
                   
                 predominate, with multiple 
               
               
                   
                   
                 inflammatory lesions evident:  
               
               
                   
                   
                 several to many comedones and  
               
               
                   
                   
                 papules/pustules, and there may or 
               
               
                   
                   
                 may not be one 
               
               
                   
                   
                 nodulocystic lesion 
               
               
                 4 
                 Severe 
                 Inflammatory lesions are more  
               
               
                   
                   
                 apparent, many comedones and  
               
               
                   
                   
                 papules/pustules, there may or  
               
               
                   
                   
                 may not be up to 2 nodulocystic lesions 
               
               
                   
               
            
           
         
       
     
     The subjects were randomized in a 2:2:2:1 ratio to the following treatment groups:
         Group 1: 109 Subjects to IDP-120 Gel (tretinoin and benzoyl peroxide BPO gel, 0.05%/2.5%);   Group 2: 98 Subjects to IDP-120 Component A (tretinoin gel, 0.05%);   Group 3: 108 Subjects to IDP-120 Component B (benzoyl peroxide, 2.5%); and   Group 4: 49 Subjects to IDP-120 vehicle gel.       

     The Group-1 subjects receive pumps that contain Component A 1  in the first chamber and Component B 1  in the second chamber. The Group-2 subjects received pumps that contain Component A 1  in the first chamber and Component A 2  in the second chamber. The Group-3 subjects receive pumps that contain Component B 1  in the second chamber and Component B 2  in the first chamber. The Group-4 subjects receive pumps that contain Component B 2  in the first chamber and Component A 2  vehicle in the second chamber. 
     All subjects received once daily, topically-applied treatment to the face for 12 weeks. Subject visits include Screening, Baseline, Week 2, Week 4, Week 8, and Week 12, at which safety and efficacy assessments were conducted. Subjects were evaluated for drug usage compliance at each post-baseline study visit (Weeks 2, 4, 8, and 12). Subjects applied their treatments at home, once daily, as instructed by the study coordinator or designee at each investigational center. 
     The investigator assessed the subject&#39;s face at each study visit. Information on reported and observed adverse events (“AEs”) was obtained at each visit. 
     Efficacy analyses were conducted on the Intent-to-Treat (“ITT”) (primary) and Per-Protocol (“PP”) (supportive) populations. 
     Primary Efficacy 
     The primary efficacy endpoints are intended to compare once daily application of IDP-120 Gel with IDP-120 Vehicle Gel and each of the individual gel components. Specifically, the primary efficacy endpoints include:
         Absolute change in inflammatory lesion count from baseline to Week 12, as summarized using descriptive and inferential statistics;   Absolute change in non-inflammatory lesion count from baseline to Week 12, as summarized using descriptive and inferential statistics;   Proportion of subjects who have a least a 2 grade reduction at Week 12 from baseline in the Evaluator&#39;s Global Severity Score and were Clear or Almost Clear, as summarized using descriptive and inferential statistics.       

     Assessment of Safety 
     Safety was evaluated by tabulations of adverse events (“AEs”), Cutaneous Safety Evaluation, and Tolerability Evaluations. Cutaneous Safety Evaluation scores (scaling and erythema) and Tolerability (itching, burning, and stinging) are presented with descriptive statistics at Baseline and at Weeks 2, 4, 8, and 12 for each treatment group. 
     Scaling: 
     0—None: No scaling 
     1—Mild: Barely perceptible, fine scales present on limited areas of the face 
     2—Moderate: Fine scale generalized to all areas of the face 
     3—Severe: Scaling and peeling of skin over all areas of the face 
     Erythema: 
     0—None: No evidence of erythema present 
     1—Mild: Slight pink coloration 
     2—Moderate: Definite redness 
     3—Severe: Marked erythema, bright red to dusky dark red in color 
     Itching: 
     0—None: No itching 
     1—Mild: Slight itching, not really bothersome 
     2—Moderate: Definite itching that is somewhat bothersome 
     3—Severe: Intense itching that may interrupt daily activities and/or sleep 
     Burning: 
     0—None: No burning 
     1—Mild: Slight burning sensation; not really bothersome 
     2—Moderate: Definite warm, burning sensation that is somewhat bothersome 
     3—Severe: Hot burning sensation that causes definite discomfort and may interrupt daily activities and/or sleep 
     Stinging: 
     0—None: No stinging 
     1—Mild: Slight stinging sensation, not really bothersome 
     2—Moderate: Definite stinging sensation that is somewhat bothersome 
     3—Severe: Stinging sensation that causes definite discomfort and may interrupt daily activities and/or sleep 
     Clinical Efficacy was determined based on the percentage of subjects who achieved treatment successes at Week-12 visit. 
     The IDP-120 group was compared to each of the other treatment groups: (1) Component-A group, (2) Component-B group, and (3) Vehicle group. 
     To be judged as a treatment success, subjects had to show two-grade improvement in EGSS from the baseline, and to have an EGSS score of “clear,” or “almost clear” at the evaluation time. Subjects not achieving treatment success by this standard were considered treatment failures, even though such subjects may have experienced some degree of improvement in their acne vulgaris. 
     Results 
     The efficacy of IDP-120 comprising tretinoin 0.05 weight percent and benzoyl peroxide 2.5 weight percent is now shown and discussed. 
     Subject baseline characteristics for per-protocol population are shown in Table 7. Inflammatory and Non-Inflammatory lesion counts at Week 12 are shown in Tables 8 and 9. Evaluator&#39;s Global Severity Scores at Week 12 are shown in Table 10. 
     
       
         
           
               
             
               
                 TABLE 7 
               
             
            
               
                   
               
               
                 Analysis of Subject Baseline Characteristics 
               
               
                 (Per-Protocol Population) 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                   
                 IDP-120 
                 IDP-120 
                   
                   
               
               
                   
                   
                 Com-  
                 Com-  
                 IDP-120 
                   
               
               
                   
                 IDP-120  
                 ponent 
                 ponent 
                 Vehicle 
                   
               
               
                   
                 Gel 
                 A 
                 B 
                 Gel 
                 P- 
               
               
                   
                 (N = 90) 
                 (N = 72) 
                 (N = 87) 
                 (N = 40) 
                 value 
               
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 Inflammatory  
                   
                   
                   
                   
                   
               
               
                 Lesion Count 
                   
                   
                   
                   
                   
               
               
                 N 
                 90 
                 72 
                 87 
                 40 
                 0.035 a   
               
               
                 Mean 
                 26.3 
                 25.6 
                 27.3 
                 24.5 
                   
               
               
                 SD 
                 5.76 
                 4.46 
                 6.42 
                 4.16 
                   
               
               
                 Median 
                 25.0 
                 24.0 
                 25.0 
                 23.5 
                   
               
               
                 Min. to Max. 
                 20 to 40 
                 20 to 40 
                 20 to 40 
                 20 to 38 
                   
               
               
                 Non-  
                   
                   
                   
                   
                   
               
               
                 Inflammatory 
                   
                   
                   
                   
                   
               
               
                 Lesion Count 
                   
                   
                   
                   
                   
               
               
                 N 
                 90 
                 72 
                 87 
                 40 
                 0.584 a   
               
               
                 Mean 
                 40.3 
                 37.8 
                 38.7 
                 35.8 
                   
               
               
                 SD 
                 19.26 
                 15.78 
                 20.25 
                 13.93 
                   
               
               
                 Median 
                 35.0 
                 35.0 
                 30.0 
                 33.0 
                   
               
               
                 Min. to Max. 
                 20 to 99 
                 20 to 88 
                 20 to 100 
                 20 to 83 
                   
               
               
                 Evaluator&#39;s  
                   
                   
                   
                   
                   
               
               
                 Global 
                   
                   
                   
                   
                   
               
               
                 Severity Score 
                   
                   
                   
                   
                   
               
               
                 N 
                 90 
                 72 
                 87 
                 40 
                 0.333 b   
               
               
                 0-Clear 
                 0 (0.0%) 
                 0 (0.0%) 
                 0 (0.0%) 
                 0 (0.0%) 
                   
               
               
                 1-Almost Clear 
                 0 (0.0%) 
                 0 (0.0%) 
                 0 (0.0%) 
                 0 (0.0%) 
                   
               
               
                 2-Mild 
                 0 (0.0%) 
                 0 (0.0%) 
                 0 (0.0%) 
                 0 (0.0%) 
                   
               
               
                 3-Moderate 
                 79 (87.8%) 
                 66 (91.7%) 
                 80 (92.0%) 
                 39 (97.5%) 
                   
               
               
                 4-Severe 
                 11 (12.2%) 
                 6 (8.3%) 
                 7 (8.0%) 
                 1 (2.5%) 
               
               
                   
               
               
                   a P-value from a one-way analysis of variance with factor of treatment group. 
               
               
                   b P-value from a Cochran-Mantel-Haenszel general association test. 
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 8 
               
             
            
               
                   
               
               
                 Summary of Inflammatory Lesion Counts at Each Evaluation 
               
               
                 (Per-Protocol Population) 
               
            
           
           
               
               
               
               
               
            
               
                   
                   
                 IDP-120 
                 IDP-120 
                 IDP-120 
               
               
                   
                 IDP-120  
                 Component  
                 Component  
                 Vehicle  
               
               
                   
                 Gel 
                 A 
                 B 
                 Gel 
               
               
                   
                 (N = 90) 
                 (N = 72) 
                 (N = 87) 
                 (N = 40) 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 Inflammatory  
                   
                   
                   
                   
               
               
                 Lesion Count 
                   
                   
                   
                   
               
               
                 Week 12 
                   
                   
                   
                   
               
               
                 N 
                 90 
                 72 
                 87 
                 40 
               
               
                 Mean 
                 12.1 
                 14.0 
                 14.0 
                 14.8 
               
               
                 SD 
                 11.20 
                 10.90 
                 10.49 
                 9.66 
               
               
                 Median 
                 8.0 
                 11.5 
                 12.0 
                 12.0 
               
               
                 Min. to Max. 
                 0 to 49 
                 0 to 48 
                 0 to 58 
                 0 to 37 
               
               
                 Absolute Change 
                   
                   
                   
                   
               
               
                 from Baseline 
                   
                   
                   
                   
               
               
                 N 
                 90 
                 72 
                 87 
                 40 
               
               
                 Mean 
                 −14.2 
                 −11.6 
                 −13.4 
                 −9.7 
               
               
                 SD 
                 10.28 
                 10.03 
                 9.29 
                 10.08 
               
               
                 Median 
                 −16.5 
                 −14.0 
                 −14.0 
                 −9.5 
               
               
                 Min. to Max. 
                 −31 to 17 
                 −29 to 23 
                 −32 to 20 
                 −27 to 14 
               
               
                 Percent Change 
                   
                   
                   
                   
               
               
                 from Baseline 
                   
                   
                   
                   
               
               
                 N 
                 90 
                 72 
                 87 
                 40 
               
               
                 Mean 
                 −55.29 
                 −46.55 
                 −50.20 
                 −38.76 
               
               
                 SD 
                 38.547 
                 41.262 
                 33.415 
                 40.406 
               
               
                 Median 
                 −68.78 
                 −59.10 
                 −52.38 
                 −41.43 
               
               
                 Min. to Max. 
                 −100.0 to  
                 −100.0 to  
                 −100.0 to  
                 −100.0 to  
               
               
                   
                 68.0 
                 104.5 
                 52.6 
                 63.6 
               
               
                   
               
               
                 Note: 
               
               
                 Last observation carried forward used to impute missing values. 
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 9 
               
             
            
               
                   
               
               
                 Summary of Non-Inflammatory Lesion Counts at Each Evaluation 
               
               
                 (Per-Protocol Population) 
               
            
           
           
               
               
               
               
               
            
               
                   
                   
                 IDP-120 
                 IDP-120 
                 IDP-120 
               
               
                   
                 IDP-120  
                 Component  
                 Component  
                 Vehicle  
               
               
                   
                 Gel 
                 A 
                 B 
                 Gel 
               
               
                   
                 (N = 90) 
                 (N = 72) 
                 (N = 87) 
                 (N = 40) 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 Non-Inflammatory  
                   
                   
                   
                   
               
               
                 Lesion Count 
                   
                   
                   
                   
               
               
                 Week 12 
                   
                   
                   
                   
               
               
                 N 
                 90 
                 72 
                 87 
                 40 
               
               
                 Mean 
                 19.7 
                 21.4 
                 28.4 
                 28.6 
               
               
                 SD 
                 16.12 
                 17.05 
                 26.51 
                 22.42 
               
               
                 Median 
                 15.0 
                 18.0 
                 22.0 
                 22.0 
               
               
                 Min. to Max. 
                 0 to 90 
                 1 to 91 
                 0 to 111 
                 1 to 97 
               
               
                 Absolute Change 
                   
                   
                   
                   
               
               
                 from Baseline 
                   
                   
                   
                   
               
               
                 N 
                 90 
                 72 
                 87 
                 40 
               
               
                 Mean 
                 −20.6 
                 −16.3 
                 −10.3 
                 −7.2 
               
               
                 SD 
                 15.27 
                 14.94 
                 19.90 
                 16.98 
               
               
                 Median 
                 −20.0 
                 −16.0 
                 −13.0 
                 −8.5 
               
               
                 Min. to Max. 
                 −68 to 9 
                 −79 to 23 
                 −89 to 41 
                 −34 to 55 
               
               
                 Percent Change 
                   
                   
                   
                   
               
               
                 from Baseline 
                   
                   
                   
                   
               
               
                 N 
                 90 
                 72 
                 87 
                 40 
               
               
                 Mean 
                 −51.62 
                 −44.12 
                 −30.15 
                 −23.57 
               
               
                 SD 
                 29.969 
                 31.315 
                 49.317 
                 46.410 
               
               
                 Median 
                 −55.53 
                 −47.30 
                 −45.45 
                 −20.24 
               
               
                 Min. to Max. 
                 −100.0 to  
                 −98.8 to  
                 −100.0 to  
                 −95.7 to  
               
               
                   
                 24.3 
                 52.3 
                 145.0 
                 148.6 
               
               
                   
               
               
                 Note: 
               
               
                 Last observation carried forward used to impute missing values. 
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 10 
               
             
            
               
                   
               
               
                 Summary of Evaluator&#39;s Global Severity Score at Each Evaluation 
               
               
                 (Per-Protocol Population) 
               
            
           
           
               
               
               
               
               
            
               
                   
                   
                 IDP-120 
                 IDP-120 
                 IDP-120 
               
               
                   
                 IDP-120  
                 Component  
                 Component  
                 Vehicle  
               
               
                   
                 Gel 
                 A 
                 B 
                 Gel 
               
               
                   
                 (N = 90) 
                 (N = 72) 
                 (N = 87) 
                 (N = 40) 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 Evaluator&#39;s Global  
                   
                   
                   
                   
               
               
                 Severity Score 
                   
                   
                   
                   
               
               
                 Week 12 
                   
                   
                   
                   
               
               
                 N 
                 90 
                 72 
                 87 
                 40 
               
               
                 0-Clear 
                 5 (5.6%) 
                 1 (1.4%) 
                 3 (3.4%) 
                 0 (0.0%) 
               
               
                 1-Almost Clear 
                 20 (22.2%) 
                 10 (13.9%) 
                 16 (18.4%) 
                 6 (15.0%) 
               
               
                 2-Mild 
                 41 (45.6%) 
                 35 (48.6%) 
                 33 (37.9%) 
                 16 (40.0%) 
               
               
                 3-Moderate 
                 19 (21.1%) 
                 25 (34.7%) 
                 32 (36.8%) 
                 18 (45.0%) 
               
               
                 4-Severe 
                 5 (5.6%) 
                 1 (1.4%) 
                 3 (3.4%) 
                 0 (0.0%) 
               
               
                 At Least Two Grade 
                   
                   
                   
                   
               
               
                 Reduction  
                   
                   
                   
                   
               
               
                 from Baseline and  
                   
                   
                   
                   
               
               
                 Achieving Clear 
                   
                   
                   
                   
               
               
                 or Almost Clear 
                   
                   
                   
                   
               
               
                 N 
                 90 
                 72 
                 87 
                 40 
               
               
                 Success 
                 25 (27.8%) 
                 11 (15.3%) 
                 19 (21.8%) 
                 6 (15.0%) 
               
               
                 Failure 
                 65 (72.2%) 
                 61 (84.7%) 
                 68 (78.2%) 
                 34 (85.0%) 
               
               
                   
               
               
                 Note: 
               
               
                 Last observation carried forward used to impute missing values. 
               
            
           
         
       
     
     Treatment success was defined as at least a two-grade improvement from Baseline in the EGSS score and an EGSS score equating to “Clear” or “Almost Clear” at Week 12, and is shown in Table 11. 
     
       
         
           
               
             
               
                 TABLE 11 
               
             
            
               
                   
               
               
                 Percentage of Subjects Achieving Treatment Success at Week 12 
               
               
                 (Per-Protocol Population) 
               
            
           
           
               
               
               
               
            
               
                 IDP-120 
                 Component A 
                 Component B 
                 Vehicle 
               
               
                   
               
               
                 27.8% 
                 15.3% 
                 21.8% 
                 15.0% 
               
               
                   
               
            
           
         
       
     
     Actual Clinical Efficacy compared to Predicted Additive Clinical Efficacy (as a percentage of subjects achieving “Treatment Success”) is shown in Table 12. The “Treatment Success” percentages for the active treatment groups (IDP-120, Component A, and Component B) were corrected for vehicle effect by subtracting the actual Vehicle group results from each to determine the net Treatment Success are shown as a percentage of the number of subjects treated. 
     
       
         
           
               
             
               
                 TABLE 12 
               
             
            
               
                   
               
               
                 Comparative Treatment Success Rates for IDP-120, Component A, 
               
               
                 and Component B (Corrected for Vehicle Effect) 
               
            
           
           
               
               
               
            
               
                 IDP-120 
                 Component A 
                 Component B 
               
               
                   
               
               
                 12.8% 
                 0.3% 
                 6.8% 
               
               
                   
               
            
           
         
       
     
     The synergistic effect of IDP-120 is illustrated by comparing the clinical efficacy from IDP-120 to the predicted efficacy from combining Component A and Component B. The vehicle-adjusted percentage of patients who were successfully treated with IDP-120 was 12.8%, which is greater than the sum of vehicle-adjusted percentages of patients who were successfully treated singly with Component A and Component B (0.3%+6.8% or 7.1%). 
     The mean scores of itching, burning, and stinging, as reported by the subjects at Week-12 evaluation are shown in Table 13. 
     
       
         
           
               
             
               
                 TABLE 13 
               
             
            
               
                   
               
               
                 Mean Scores of Itching, Burning, and Stinging for IDP-120,  
               
               
                 Component A, Component B, and Vehicle 
               
            
           
           
               
               
               
               
               
            
               
                 Adverse  
                   
                 Component 
                 Component 
                   
               
               
                 Event 
                 IDP-120 
                 A 
                 B 
                 Vehicle 
               
               
                   
               
               
                 Itching 
                 0.06 
                 0.16 
                 0.09 
                 0.05 
               
               
                 Burning 
                 0.18 
                 0.11 
                 0.05 
                 0.00 
               
               
                 Stinging 
                 0.12 
                 0.05 
                 0.03 
                 0.00 
               
               
                   
               
            
           
         
       
     
     The mean scores of itching, burning, and stinging for IDP-120, Component A, and Component B, corrected for the effect of vehicle are shown in Table 14. 
     
       
         
           
               
             
               
                 TABLE 14 
               
             
            
               
                   
               
               
                 Mean Scores of Itching, Burning, and Stinging for IDP-120,  
               
               
                 Component A, and Component B, Corrected for the Effect of Vehicle 
               
            
           
           
               
               
               
               
               
            
               
                 Adverse  
                   
                   
                   
                 Component A + 
               
               
                 Event 
                 IDP-120 
                 Component A 
                 Component B 
                 Component B 
               
               
                   
               
               
                 Itching 
                 0.01 
                 0.11 
                 0.04 
                 0.15 
               
               
                 Burning 
                 0.18 
                 0.11 
                 0.05 
                 0.16 
               
               
                 Stinging 
                 0.12 
                 0.05 
                 0.03 
                 0.08 
               
               
                   
               
            
           
         
       
     
     The mean scores of scaling, erythema, hypopigmentation, and hyperpigmentation, at Week-12 evaluation for IDP-120, Component-A, Component-B, and Vehicle groups are shown in Table 15. 
     
       
         
           
               
             
               
                 TABLE 15 
               
             
            
               
                   
               
               
                 Mean Scores of Scaling, Erythrema, Hypopigmentation,  
               
               
                 and Hyperpigmentation 
               
            
           
           
               
               
               
               
               
            
               
                 Adverse Reaction 
                 IDP-120 
                 Component A 
                 Component B 
                 Vehicle 
               
               
                   
               
               
                 Scaling 
                 0.15 
                 0.13 
                 0.10 
                 0.07 
               
               
                 Erythema 
                 0.23 
                 0.19 
                 0.15 
                 0.16 
               
               
                 Hypopigmentation 
                 0.02 
                 0.06 
                 0.03 
                 0.00 
               
               
                 Hyperpigmentation 
                 0.17 
                 0.17 
                 0.19 
                 0.16 
               
               
                   
               
            
           
         
       
     
     The mean scores of scaling, erythrema, hypopgmentation, and hyperpigmentation for IDP-120, Component A, and Component B corrected for the effect of the vehicle are shown in Table 16. 
     
       
         
           
               
             
               
                 TABLE 16 
               
             
            
               
                   
               
               
                 Mean Scores of Scaling, Erythrema, Hypopigmentation, and  
               
               
                 Hyperpigmentation, Corrected for the Effect of the Vehicle 
               
            
           
           
               
               
               
               
               
            
               
                   
                   
                 Com-  
                 Com-  
                 Component  
               
               
                 Adverse  
                   
                 ponent 
                 ponent 
                 A + 
               
               
                 Reaction 
                 IDP-120 
                 A 
                 B 
                 Component B 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 Scaling 
                 0.08 
                 0.06 
                 0.03 
                 0.09 
               
               
                 Erythema 
                 0.07 
                 0.03 
                 −0.01 (a)   
                 0.03 
               
               
                 Hypopigmentation 
                 0.02 
                 0.06 
                 0.03 
                 0.09 
               
               
                 Hyperpigmentation 
                 0.01 
                 0.01 
                 0.03 
                 0.04 
               
               
                   
               
               
                 Notes: 
               
               
                   (a) negative values are taken to be zero for the purposes of comparison. 
               
            
           
         
       
     
     Surprisingly, the corrected mean scores for itching, scaling, hypopigmentation, and hyperpigmentation for IDP-120 are lower than those predicted for the combination of Component A and Component B. Thus, IDP-120 is synergistically beneficial with respect to these adverse reactions. 
     In another aspect, the present invention provides a method for treating acne vulgaris. The method comprises topically applying to an affected area of the body of a subject suffering from acne vulgaris any one of the compositions of the present invention, as disclosed herein, one or more times per day for a period of time sufficient to treat such acne vulgaris. For example, such a period of time may be 1 to 12 weeks, or 1 to 24 weeks, or longer as needed. For example, such a period of time may be one week, two weeks, four weeks, eight weeks, twelve weeks, eighteen weeks, twenty-four weeks, or longer as needed. For example, a composition of the present invention is applied topically to affected areas of the body once per day for 12 weeks. Alternatively, it may be applied two or three times per day for 1-12 weeks. Alternatively, it may be applied once per day for one week to six months. For example, it may be applied once per day for two weeks, four weeks, eight weeks, twelve weeks, eighteen weeks, or twenty-four weeks. 
     In yet another aspect, the present invention provides a method of treating acne vulgaris topically with pharmaceutical composition comprising a combination of: (a) tretinoin at a concentration of about 0.01-0.1 weight percent of the composition; and (b) benzoyl peroxide at a concentration of about 1-10 weight percent of the composition; wherein the composition is administered topically to an affected area of a subject in an amount, at a frequency, and for a period of time sufficient to treat said acne vulgaris; and wherein the combination provides synergistic clinical efficacy, as measured by treatment success. 
     In yet another aspect, the present invention provides a method of treating acne vulgaris topically with pharmaceutical composition comprising a combination of: (a) tretinoin at a concentration of about 0.01-0.1 weight percent of the composition; and (b) benzoyl peroxide at a concentration of about 1-10 weight percent of the composition; wherein the composition is administered topically to an affected area of a subject in an amount, at a frequency, and for a period of time sufficient to treat said acne vulgaris; and wherein the clinical success rate of the combination is synergistic compared to the clinical success rate of the tretinoin component at the same concentration used alone plus the clinical success rate of the benzoyl peroxide component used alone at the same concentration. 
     In yet another aspect, the present invention provides a method of treating acne vulgaris topically with pharmaceutical composition comprising a combination of: (a) tretinoin at a concentration of about 0.03-0.08 (or 0.04-0.07, or 0.01-0.06) weight percent of the composition; and (b) benzoyl peroxide at a concentration of about 1-5 (or 1.5-4, or 2-3) weight percent of the composition; wherein the composition is administered topically to an affected area of a subject in an amount, at a frequency, and for a period of time sufficient to treat said acne vulgaris; and wherein the clinical success rate of the combination is synergistic compared to the clinical success rate of the tretinoin component at the same concentration used alone plus the clinical success rate of the benzoyl peroxide component used alone at the same concentration. 
     In yet another aspect, the present invention provides a method of treating acne vulgaris topically with pharmaceutical composition comprising a combination of: (a) tretinoin at a concentration of about 0.03-0.08 (or 0.04-0.07, or 0.01-0.06) weight percent of the composition; and (b) benzoyl peroxide at a concentration of about 1-5 (or 1.5-4, or 2-3) weight percent of the composition; wherein the composition is administered topically to an affected area of a subject one or more times per day for 1-24 weeks, in an amount sufficient to treat said acne vulgaris; and wherein the clinical success rate of the combination is synergistic compared to the clinical success rate of the tretinoin component at the same concentration used alone plus the clinical success rate of the benzoyl peroxide component used alone at the same concentration. 
     In yet another aspect, the present invention provides a method of treating acne vulgaris topically with pharmaceutical composition comprising a combination of: (a) tretinoin at a concentration of about 0.05 weight percent of the composition; and (b) benzoyl peroxide at a concentration of about 2.5 weight percent of the composition; wherein the composition is administered topically to an affected area of a subject 1-4 times per day for 1-24 weeks, in an amount sufficient to treat said acne vulgaris sufficient to treat said acne vulgaris; and wherein the clinical success rate of the combination is synergistic compared to the clinical success rate of the tretinoin component at the same concentration used alone plus the clinical success rate of the benzoyl peroxide component used alone at the same concentration. 
     In yet another aspect, the present invention provides a method of treating acne vulgaris topically with pharmaceutical composition comprising a combination of: (a) tretinoin at a concentration of about 0.05 weight percent of the composition; and (b) benzoyl peroxide at a concentration of about 2.5 weight percent of the composition; wherein the composition is administered topically to an affected area of a subject one or two times per day for 2, 4, 6, 8, 10, or 12 weeks, in an amount sufficient to treat said acne vulgaris; and wherein the clinical success rate of the combination is synergistic compared to the clinical success rate of the tretinoin component at the same concentration used alone plus the clinical success rate of the benzoyl peroxide component used alone at the same concentration. 
     In yet another aspect, the present invention provides a method of treating acne vulgaris topically with pharmaceutical composition comprising a combination of: (a) tretinoin at a concentration of about 0.05 weight percent of the composition; and (b) benzoyl peroxide at a concentration of about 2.5 weight percent of the composition; wherein the composition is administered topically to an affected area of a subject once per day for 12 weeks, in an amount sufficient to treat said acne vulgaris; and wherein the clinical success rate of the combination is synergistic compared to the clinical success rate of the tretinoin component at the same concentration used alone plus the clinical success rate of the benzoyl peroxide component used alone at the same concentration. 
     In yet another aspect, the present invention provides a method of treating acne vulgaris topically with pharmaceutical composition comprising a combination of: (a) tretinoin at a concentration of about 0.05 weight percent of the composition; and (b) benzoyl peroxide at a concentration of about 2.5 weight percent of the composition; wherein the composition is administered topically to an affected area of a subject once per day for 12 weeks, in an amount sufficient to treat said acne vulgaris; wherein the clinical success rate of the combination is synergistic compared to the clinical success rate of the tretinoin component at the same concentration used alone plus the clinical success rate of the benzoyl peroxide component used alone at the same concentration; and wherein the method provides a synergistically beneficial effect with respect to at least one adverse reaction. In one embodiment, such adverse reaction is selected from the group consisting of itching, scaling, hypopigmentation, and hyperpigmentation. 
     It is also contemplated that in certain circumstances, a period of non-treatment may be allowed between two periods of treatment with a composition of the present invention. 
     In still another aspect, such amount sufficient to treat acne vulgaris is about 0.5-2 gram per application. In one embodiment, such amount sufficient to treat acne vulgaris is about 0.7 gram per application. 
     In still another aspect, a composition of the present invention may be used in conjunction with another method of treatment of acne vulgaris, such as a topical antibiotic drug (e.g., clindamycin), an oral antibiotic drug, or a topical or oral anti-inflammatory drug. 
     While the present disclosure shows and describes a number of exemplary embodiments, it will be manifest to those skilled in the art that various further modifications may be made without departing from the spirit and scope of the underlying inventive concept and that the same is not limited to particular compositions, processes, methods, or structures herein shown and described.