NxThera Inc., a St. Paul-based medical device company, announced on Wednesday it raised $12.6 million in Series B equity financing.

The company said it will use the money to launch a clinical study and toward gaining regulatory approval for its product in Europe. NxThera is developing therapy to treat an enlarged prostate condition known as benign prostatic hyperplasia (BPH). The company said its treatment uses vapor on the prostate, decreasing the size of the tissue and making it easier for the patient to urinate.

The financing round was led by Minnetonka-based American Medical Systems Inc., a supplier of pelvic devices and therapies. Arboretum Ventures, Aberdare Ventures and GDN Holdings also participated in the round.

NxThera also announced Dr. Glen Nelson, chairman of GDN Holdings, has joined its board.