Arcutis Biotherapeutics saw a 15 percent rise in its share price after it said Sept. 29 that it will offer 4 million shares to the public and sell another $35 million in stock to an affiliate of one of its directors.

Arcutis closed at $31.04, a gain of $4.28 after it announced the dual track equity offering. The Westlake Village-based company is in late-stage trials on several drugs aimed at treating dermatological inflammation and related symptoms.

OrbiMed Advisors LLC will make the $35 million private placement investment, which is not contingent on the follow-on stock offering, an Arcutis news release said. Jonathan Silverstein, a member of the Arcutis board, is a managing partner at OrbiMed.

At closing prices the total investment would exceed $150 million, significantly bolstering the $223 million the company had on hand in cash.

Leading the underwriting are Goldman Sachs, Cowen & Co. and Guggenheim Securities.