asthmatx-logo.jpgAsthmatx, a Mountain View, Calif., developer of a bronchial device for asthma treatment, raised $50 million by selling a 15% stake to Olympus Medical Systems, a unit of Japan’s camera and precision-device maker Olympus.

Last October, Asthmatx withdrew an IPO at the last minute, citing a desire to pursue “alternative strategic options” — that is, better offers. And it seems to have found one; Dan Primack at PE Wire figures that Asthmatx’s current $280 million pre-money valuation is close to twice what it would have been in the planned IPO.

Asthmatx makes an experimental device that uses heat to thin smooth-muscle tissue in the airways of asthmatic patients, with the aim of inhibiting the muscular contractions typical of an asthma attack. (The company gently refers to this process as “delivering controlled thermal energy” to the airway’s smooth muscle.) Known formally as bronchial thermoplasty, the technique involves a catheter and a small heatable wire “basket” that a physician can extend into the airways of the lungs. Patients are sedated during the procedure, but don’t have to be hospitalized.

In March, a team of doctors funded by Asthmatx reported in the New England Journal of Medicine that bronchial thermoplasty with the company’s Alair device appeared to reduce the frequency of asthmatic attacks compared to a control group. That study, however, is difficult to interpret, as a significant number of patients dropped out during a “washout” period in which they had to give up their asthma medications for two weeks prior to the onset of treatment. The researchers also cautioned that thermoplasty “may increase the potential for a strong placebo effect,” which of course would make it difficult to know how much the treatment actually helped patients.

Asthmatx had previously raised $42.5 million in venture funding from a number of backers, including Polaris Venture Partners, Menlo Ventures, Vanguard Ventures, HBM BioCapital, MedVenture Associates, Boston Scientific and Montreux Equity Partners. A release of sorts on the funding is here; VentureWire has more here (subscription required).