Safety and Efficacy of Topically Applied Selected Cutibacterium acnes Strains over Five Weeks in Patients with Acne Vulgaris: An Open-label, Pilot Study

Abstract

This open-label, pilot study enrolled men and women (18years) with acne vulgaris. In 14 enrolled patients, skin microbiome composition shifted towards study formulations. No untoward tolerability, visible irritation, or significant flare-ups were observed. Non-inflamed lesions and skin pH were reduced. Modulation of Cutibacterium acnes towards the non-acne causing strains on the skin of patients with acne was safe. C. acnes was formerly thought to be the cardinal cause of acne; however, recently some, but not all, strains of C. acnes were found to be responsible. This microbiome modulation approach as therapy requires validation in future clinical studies. Imbalance in skin microflora, particularly related to certain Cutibacterium acnes strains, may trigger acne. Application of non-acne-causing strains to the skin may modulate the skin microbiome and thereby lead to a reduction in acne. This pilot study evaluates the safety and efficacy of microbiome modulation on acneprone skin. The study had 2 phases: active induction (5% benzoyl peroxide gel, 7 days) and interventional C. acnes strains treatment (5 weeks). Patients were randomized to either topical skin formulations PT1 (2 strains of C. acnes Single Locus Sequence Typing [SLST] type C3 and K8, 50% each) or PT2 (4 strains of C. acnes SLST type C3 [55%], K8 [5%], A5 [30%] and F4 [10%]). Safety and efficacy was evaluated in 14 patients (PT1=8/14, PT2=6/14). Skin microbiome composition shifted towards study formulations. No untoward adverse events, visible irritation, or significant flare-up were observed. Non-inflamed lesions and skin pH were reduced. Comedone counts improved clinically with no deterioration in inflammatory lesions.

Developments and challenges in dermatology: an update from the Interactive Derma Academy (IDeA) 2019

“…In particular, altering the composition of C. acnes strains on the skin, through topical application of strains that are capable of inhibiting pathogenic strains, could reduce inflammation. This is supported by a pilot study in which topical application of selected C. acnes strains over 5 weeks reduced non‐inflamed lesions and improved comedone counts without causing irritation, flare‐up or deterioration in inflammatory lesions 47 . Microbiome modulation also significantly reduced non‐inflamed lesion counts in patients with acne after 42 days, despite a relative increase in C. acnes bacteria 47 .…”

“…This is supported by a pilot study in which topical application of selected C. acnes strains over 5 weeks reduced non-inflamed lesions and improved comedone counts without causing irritation, flare-up or deterioration in inflammatory lesions. 47 Microbiome modulation also significantly reduced non-inflamed lesion counts in patients with acne after 42 days, despite a relative increase in C. acnes bacteria. 47 This confirms that downregulation of pathogenic C. acnes strains is possible through increasing the number of beneficial strains of C. acnes; however, it is not clear if continuous or intermittent treatment is necessary.…”

“…47 Microbiome modulation also significantly reduced non-inflamed lesion counts in patients with acne after 42 days, despite a relative increase in C. acnes bacteria. 47 This confirms that downregulation of pathogenic C. acnes strains is possible through increasing the number of beneficial strains of C. acnes; however, it is not clear if continuous or intermittent treatment is necessary.…”

“…44,45 Modulation of the microbiome therefore represents a novel treatment strategy for acne. 46,47 In particular, altering the composition of C. acnes strains on the skin, through topical application of strains that are capable of inhibiting pathogenic strains, could reduce inflammation. This is supported by a pilot study in which topical application of selected C. acnes strains over 5 weeks reduced non-inflamed lesions and improved comedone counts without causing irritation, flare-up or deterioration in inflammatory lesions.…”

“…Modulation of the microbiome therefore represents a novel treatment strategy for acne 46,47 . In particular, altering the composition of C. acnes strains on the skin, through topical application of strains that are capable of inhibiting pathogenic strains, could reduce inflammation.…”