Dermal Irritation, Sensitization, and Safety of Fixed-Dose Triple-Combination Clindamycin Phosphate 1.2%/Benzoyl Peroxide 3.1%/Adapalene 0.15% Gel in Healthy Participants

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Zoe D. Draelos, MD
Emil A. Tanghetti, MD
Linda Stein Gold, MD
Leon H Kircik, MD
Neal Bhatia, MD
Joshua A. Zeichner, MD
Jeffrey L. Sugarman, MD, PhD


Tolerability, Irritation, CIPT, RIPT, Retinoid, BPO, Adapalene, Clindamycin, Antiobiotic, Combination


Introduction: IDP-126 polymeric mesh gel (clindamycin phosphate 1.2%/benzoyl peroxide [BPO] 3.1%/adapalene 0.15%) is the first triple-combination, fixed-dose topical acne product in development and it addresses major acne pathophysiological processes. IDP-126 demonstrated superior efficacy to vehicle and component dyads, with good safety/tolerability in a phase 2 study of participants with moderate-to-severe acne. The objectives of this study were to assess dermal irritation/sensitization and safety of IDP-126 gel in two phase 1 studies and to compare irritancy of IDP-126 gel and commercially available BPO 2.5%/adapalene 0.3% gel in one phase 1 study of healthy participants.

Methods: Two phase 1, randomized, evaluator-blinded, within-participant, dermal safety studies enrolled healthy participants aged ≥18 years (N=234, repeat insult patch test [RIPT]; N=45, cumulative irritation patch test [CIPT]). Patches were applied to the upper back multiple times over 6-8 weeks (RIPT) or every 24 hours for 21 days (CIPT). Patches contained: IDP-126 gel, vehicle gel, saline 0.9% (RIPT/CIPT), sodium lauryl sulfate (SLS) 0.5% (CIPT), or branded BPO 2.5%/adapalene 0.3% gel (CIPT). Participants in each study received all treatments. Endpoints comprised sensitization potential (RIPT), mean cumulative/total irritation scores, and treatment-emergent adverse events (TEAEs).

Results: Overall, irritation with IDP-126 was moderate and not clinically significant. CIPT: IDP-126 was “moderately irritating” (mean score: 1.29), which was significantly less irritating than BPO/adapalene (1.96; P<0.001), statistically similar to SLS (1.17), and more irritating than saline or vehicle (~0.30; P<0.001). RIPT: no participants had investigator-confirmed sensitization to any treatments. In both studies, no TEAEs were related to treatment.

Conclusions: In two phase 1 studies, fixed-dose, triple-combination clindamycin phosphate 1.2%/ BPO 3.1%/adapalene 0.15% polymeric mesh gel had moderate irritancy and no confirmed sensitization in healthy participants. Additionally, IDP-126 demonstrated significantly less irritation versus commercially available, branded BPO 2.5%/adapalene 0.3% gel. IDP-126 demonstrated good safety/tolerability, mirroring the phase 2 study results.


Funding: Ortho Dermatologics


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