Comparison of clindamycin/benzoyl peroxide, tretinoin plus clindamycin, and the combination of clindamycin/benzoyl peroxide and tretinoin plus clindamycin in the treatment of acne vulgaris: a randomized, blinded study

Journal of Drugs in Dermatology, Sept-Oct, 2005 by Steven Bowman, Michael Gold, Adnan Nasir, George Vamvakias

Demographic and baseline characteristics of the ITT population are presented in Table 2. At baseline, patients in the 3 groups had similar numbers of papules, although patients in Group 2 (tretinoin clindamycin) had significantly higher numbers of comedones compared with Groups 1 and 3 and patients in Group 1 (clindamycin/benzoyl peroxide) had significantly lower numbers of pustules compared with Groups 2 and 3. The mean Investigator's Global Acne Severity score was 2.1 to 2.2 in all groups.

Lesion Counts

The overall number of inflammatory lesions was considerably reduced during the 10-week study period. The mean percent reduction from baseline in inflammatory lesions was 65.7% for Group 1 (clindamycin/benzoyl peroxide), 52.5% for Group 2 (tretinoin clindamycin), and 69.3% for Group 3 (clindamycin/benzoyl peroxide tretinoin clindamycin) (Figure 1). At Week 10, the mean percent reduction was significantly greater for Group 1 compared with Group 2 (P = .05) and for Group 3 compared with Group 2 (P = .02). There was no significant difference between Group 1 and Group 3 (P = .69). At Week 2, the percent reduction for Group 1 was significantly greater than both Group 2 (P = .01) and Group 3 (P = .02), highlighting the rapid onset of action of clindamycin/benzoyl peroxide.

The number of non-inflammatory lesions was also reduced during the study. At Week 10, numerically greater mean percent reductions were seen in the 2 groups that included clindamycin/benzoyl peroxide compared with the tretinoin clindamycin group (Group 1 = 57.2%, Group 3 = 61.0% vs. Group 2 = 46.2%) (Figure 2). Reductions in total lesion counts at Week 10 followed the same pattern (Group 1 = 61.4%, Group 3 = 62.6% vs. Group 2 = 49.6%) (Figure 3).

Investigator's Global Acne Severity Score

At Week 10, significantly more patients in Group 3 achieved an Investigator's Global Acne Severity score of 0 to 0.5 compared with patients in Group 2 (50% vs. 14%, P = .01). There was no statistical difference between the numbers of patients achieving an Investigator's Global Acne Severity score of 0 to 0.5 between Group 1 and Group 3. Patients in Group 1 had a success rate of 29%, approximately twice as high as Group 2, but this difference did not reach statistical significance.

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Tolerability

All treatment regimens were safe and generally well tolerated. Substantially more adverse events were reported for the combination regimen of clindamycin/benzoyl peroxide tretinoin clindamycin than for either regimen alone. Overall, more application site reactions occurred with tretinoin clindamycin than with clindamycin/benzoyl peroxide. The most common adverse events were application site irritation and application site dryness (Table 3). Adverse events were primarily mild to moderate in severity. During the study, the 4 severe adverse events which were reported included application site dryness (1 patient each in Groups 1 and 2), application site irritation (1 patient in Group 2), and facial peeling (1 patient in Group 2). All patients recovered without sequelae. Two patients (in Group 3) discontinued due to facial burning of moderate severity, with discontinuations occurring within the first week of study drug administration. There were no serious adverse events reported during the trial.