A Malvern biotechnology company, Aclaris Therapeutics, said Tuesday that it has acquired a St. Louis drug-discovery start-up for $10 million in cash and about 350,000 shares of common stock valued at about $10 million.

The acquisition of Confluence Life Sciences will expand Aclaris' pipeline to treat inflammatory and autoimmune skin disorders and "relevant adjacent therapeutic areas," the company said.

Confluence develops kinase inhibitors to treat inflammatory and immunological disorders and cancer. Its leadership team includes several former Pfizer Inc. kinase program officials.

"This transaction expands an existing collaboration between two companies with a striking degree of complementarity," said Confluence CEO Walter Smith, former vice president and global head of Pfizer Inflammation Research.

Aclaris on Tuesday reported a loss of $14.8 million, or 56 cents a share, in the second quarter ended June 30. Wall Street analysts expected a loss of 68 cents a share.

Aclaris, founded in 2012 to develop medicines for dermatologic conditions, filed a new-drug application with the Food and Drug Administration in February to approve its hydrogen peroxide-formulated topical treatment for noncancerous skin growths in the United States. The skin condition, seborrheic keratosis, affects more than 83 million Americans.

If approved, the topical solution, administered in a physician's office, would be the first FDA-approved topical treatment. Existing treatments include freezing the growth, using liquid nitrogen, or scraping it off, which can cause scarring and changes in skin color, the company said. The growths often appear on the face, chest, shoulders, or back and have a waxy, scaly, slightly elevated appearance that can vary in color from light tan to dark brown or black. Aclaris is pursuing additional dermatological uses for the investigational drug, referred to as A-101, such as treatment of common warts.

Aclaris shares were down $0.05, or 0.19 percent, to $26.95 in early trading.