In mid-May, pharma giant Pfizer agreed to buy Anacor Pharmaceuticals for a total transaction value, net of cash, of $5.2 billion. Anacor is a biopharmaceutical company concentrated on discovering, developing and commercializing novel small-molecule therapeutics derived from its boron chemistry platform. The company’s first approved product, Kerydin (tavaborole) topical solution 5%, is an oxaborole antifungal that was FDA-approved during July 2014 for treating toenail onychomycosis.

Anacor’s flagship asset crisaborole is a differentiated non-steroidal topical PDE4 inhibitor with anti-inflammatory properties. The new drug candidate is undergoing FDA review for treating mild-to-moderate atopic dermatitis, commonly known as eczema.

With approval of crisaborole, Pfizer is expected to become a market leader in the field of eczema. The steroid-free topical ointment is the first of a new wave of atopic dermatitis treatments to be reviewed by the Food and Drug Administration. The closest rival appears to be the injectable therapy dupilumab from Regeneron Pharmaceuticals in collaboration with Sanofi. Dupilumab is an antibody against the interleukin-4 receptor, through which both interleukin-4 and interleukin-13 signal.

In late-stage studies, crisaborole and dupilumab greatly reduced eczema symptoms without side effects evident in already-marketed eczema products. According to analysts, the two drugs could generate combined yearly worldwide revenue of more than $9 billion and face no significant competition for years. The worldwide eczema drug market is estimated at about $4 billion in sales, consisting primarily of topical steroids.

Gil Yosipovitch, chairman of dermatology at Temple University School of Medicine, suggested to Reuters that about 60 to 80 percent of patients would be candidates for Anacor’s product, and dupilumab would be more likely appropriate for patients with a more severe form of the disease.