Development of a topical bacteriophage gel targeting Cutibacterium acnes for acne prone skin and results of a phase 1 cosmetic randomized clinical trial

Background

Topical antibiotics are frequently used to treat acne vulgaris. Their prolonged use, often for longer durations than recommended, has led to antibiotic resistance in Cutibacterium acnes (C. acnes), a bacterium implicated in acne pathophysiology. Bacteriophage (phage), which specifically target C. acnes by a different mechanism of action and do not harm potentially beneficial bacteria, may offer an alternative approach for improvement of the appearance of acne prone skin.

Objectives

To identify and characterize C. acnes targeting phage, carry out a comprehensive preclinical safety evaluation of phages selected for further development and examine their safety, tolerability and ability to target facial C. acnes when applied topically in a cosmetic clinical study including participants with mild‐to‐moderate acne.

Methods

Phages were isolated by conventional microbiological methods also used to examine their breadth of host range on different C. acnes strains and specificity to this bacterial species. Safety assessment of three selected phages was carried out by complete genomic analysis to assure the absence of undesired sequences and by ex vivo models employed to evaluate the safety, irritability and potential systemic bioavailability of phage applied topically. A randomized, controlled clinical study assessed safety, tolerability and efficacy in targeting facial C. acnes.

Results

Wide host range phages that also target antibiotic resistant C. acnes were identified. Their genomes were shown to be free of undesired genes. The three‐phage cocktail, BX001, was not irritant to human skin or ocular tissues in ex vivo models and did not permeate through human epidermis. In a cosmetic clinical study, topically applied BX001 was safe and well tolerated and reduced the facial burden of C. acnes.

Conclusions

Combined in silico and ex vivo approaches successfully predicted the observed safety and efficacy of C. acnes targeting phage when these were topically administered in a well‐controlled cosmetic clinical study.

Conditions determining the local stability of populations

The conditions that determine the local stability classification of an equilibrium population configuration are analyzed. The population investigated is age-structured and density-dependent, where density is determined by an age-weighted population size. 2 demographic parameters are introduced: the marginal birth rate and the marginal death rate, which describe the marginal density-dependence of the birth and death rates of the equilibrium population. Certain necessary and/or sufficient conditions determining stability are developed, most of them involving the net reproduction rate of the population, and examples illustrating these conditions are presented.

Effects of induced total-body hyperthermia on phosphorus metabolism in humans

The effects of total-body hyperthermia on phosphorus homeostasis are controversial. To evaluate the problem, 10 clearance studies were performed in seven patients undergoing total-body hyperthermia as an adjunct to the treatment of solid malignant tumors. Total-body hyperthermia was associated with significant reduction in plasma phosphorus concentration from a baseline value of 3.51 +/- 0.18 to 0.6 +/- 0.1 mg/dl (p less than 0.001), returning to baseline following cessation of total-body hyperthermia. The clearance of phosphorus increased from 15.2 +/- 2.5 to 26.1 +/- 3.1 ml per minute (p less than 0.01), and the fractional excretion of phosphorus increased from 11.37 +/- 2.2 to 47.68 +/- 9.7 percent (p less than 0.01). The reduction in plasma phosphorus during total-body hyperthermia was also associated with a significant reduction in the renal threshold phosphorus concentration from 3.17 +/- 0.16 to 0.38 +/- 0.08 (p less than 0.001). The changes in phosphorus homeostasis during total-body hyperthermia were independent of changes in circulating parathyroid hormone level, urinary cyclic AMP excretion, and arterial carbon dioxide tension.

Abortion need and services in the United States, 1974-1975

More than one million legal abortions were performed in the United States last year--but one-half to three-quarters of a million women in need of abortion services were still unable to obtain them. Ninety percent of all abortions are now performed in the woman's home state, but services are still highly concentrated within states--typically in one or two metropolitan centers where most services are provided by nonhospital clinics. Only one-fourth of hospitals-and fewer than one-fifth of public hospitals-provide any abortion services. Many poor, rural and teenage women who can least afford to travel to obtain legal abortions will continue to be denied access to the services they want and need.