A Efficacy and Safety of Duac™Compared With Clindamycin Phosphate Gel in the Treatment of Mild to Moderate Acne Vulgaris

Inclusion Criteria: 1. Male and female subjects between 12 and 45 years of age, inclusive age will be calculated by date of birth, from 0 at birth. 2. Subjects who have: i. A minimum of 17 but not more than 60 facial inflammatory lesions (papules plus pustules), and no more than 1 facial nodular lesion, with NO cystic lesions. and ii. A minimum of 20 but not more than 125 facial noninflammatory lesions (open and closed comedones). 3. Subjects who have an ISGA score of 2 or 3 at Baseline. 4. Subjects 18 years of age or older must provide written informed consent (according to any local or national authorization requirements). Subjects under the legal age of consent must provide assent and have written informed consent of both the subject and a parent or the legal guardian (according to any local or national authorization requirements). 5. Subjects who are willing and able to complete the study, to understand and comply with the requirements of the study, abide by the restrictions, apply the medication as instructed, and return for the required study visits. 6. Subjects who are in good health and free from any clinically significant disease, other than acne vulgaris, that might interfere with the study evaluations. 7. Female subjects of childbearing potential must have a negative pregnancy test at baseline. Sexually active females of childbearing potential participating in the study must use a medically acceptable method of contraception for at least 6 consecutive months prior to start of study treatment, and must use a medically acceptable method of contraception while receiving protocol-assigned product. A woman of childbearing potential is defined as one who is biologically capable of becoming pregnant; including perimenopausal women who are less than 2 years from their last menses. Medically acceptable contraceptive methods include the following: * Hormonal contraception, including oral, injectable, or implantable methods started at least 6 months prior to screening. * Reliable barrier methods include condoms and diaphragms. A cervical cap is also a reliable barrier method, provided that the female subject has never given birth naturally. The combined use of a condom and spermicide constitute 2 forms of acceptable nonhormonal contraception, provided that they are both used properly. The use of spermicide alone and the improper use of condoms are inferior methods of contraception. Subjects with surgical sterilization, including tubal ligation or partner's vasectomy, must use a form of nonhormonal contraception. A barrier method or sterilization plus spermatocide are acceptable. Females who are not currently sexually active must agree to use a medically accepted method of contraception should they become sexually active while participating in the study. Subjects who have been treated with estrogens, androgens, or anti-androgenic agents used for prevention of pregnancy (and not for control of acne) for at least 6 consecutive months prior to the first dose of investigational product may enrol as long as they do not expect to change dose, drug, or discontinue use during the study. Exclusion Criteria: 1. Female subjects who are pregnant, trying to become pregnant, or who are lactating. 2. Subjects who have cystic acne lesions, acne conglobata, acne fulminans, or secondary acne (e.g. chloracne or drug-induced acne). 3. Subjects who have any clinically relevant finding at their baseline physical examination or medical history such as severe systemic diseases or diseases of the facial skin other than acne vulgaris. 4. Subjects who have facial hair that may prevent the accurate assessment of acne vulgaris grade or lesion count. 5. Subjects who have a history or presence of regional enteritis or inflammatory bowel disease (e.g. ulcerative colitis, pseudomembranous colitis, chronic diarrhoea, or a history of antibiotic-associated colitis, bloody diarrhoea) or similar symptoms. 6. Subjects who have used a prohibited medication, or undergone a prohibited procedure or treatment within the required washout period. 7. Subjects who have a known hypersensitivity or previous allergic reaction to any of the active components, lincomycin, or excipients of the investigational product. 8. Subjects who are employees of a clinical research organization involved in the study, Stiefel, or GSK or who are an immediate family member (partner, offspring, parents, siblings, or sibling's offspring) of an employee, the investigator, or his/her study staff. 9. Subjects who have a member of the same household in this study at the same time. 10. Subjects who have used traditional remedies known to affect acne vulgaris within the last 4 weeks. 11. Subjects who have had any major illness within 30 days before study enrolment. 12. Subjects who have any other condition that in the judgement of the investigator would put the subject at unacceptable risk for participation in the study. 13. Subjects who have participated in any clinical trials or taken any investigate drugs within 4 weeks before study enrolment.